1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Shared application/kernel submission and completion ring pairs, for
4  * supporting fast/efficient IO.
5  *
6  * A note on the read/write ordering memory barriers that are matched between
7  * the application and kernel side.
8  *
9  * After the application reads the CQ ring tail, it must use an
10  * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
11  * before writing the tail (using smp_load_acquire to read the tail will
12  * do). It also needs a smp_mb() before updating CQ head (ordering the
13  * entry load(s) with the head store), pairing with an implicit barrier
14  * through a control-dependency in io_get_cqring (smp_store_release to
15  * store head will do). Failure to do so could lead to reading invalid
16  * CQ entries.
17  *
18  * Likewise, the application must use an appropriate smp_wmb() before
19  * writing the SQ tail (ordering SQ entry stores with the tail store),
20  * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
21  * to store the tail will do). And it needs a barrier ordering the SQ
22  * head load before writing new SQ entries (smp_load_acquire to read
23  * head will do).
24  *
25  * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
26  * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
27  * updating the SQ tail; a full memory barrier smp_mb() is needed
28  * between.
29  *
30  * Also see the examples in the liburing library:
31  *
32  *	git://git.kernel.dk/liburing
33  *
34  * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
35  * from data shared between the kernel and application. This is done both
36  * for ordering purposes, but also to ensure that once a value is loaded from
37  * data that the application could potentially modify, it remains stable.
38  *
39  * Copyright (C) 2018-2019 Jens Axboe
40  * Copyright (c) 2018-2019 Christoph Hellwig
41  */
42 #include <linux/kernel.h>
43 #include <linux/init.h>
44 #include <linux/errno.h>
45 #include <linux/syscalls.h>
46 #include <linux/compat.h>
47 #include <net/compat.h>
48 #include <linux/refcount.h>
49 #include <linux/uio.h>
50 #include <linux/bits.h>
51 
52 #include <linux/sched/signal.h>
53 #include <linux/fs.h>
54 #include <linux/file.h>
55 #include <linux/fdtable.h>
56 #include <linux/mm.h>
57 #include <linux/mman.h>
58 #include <linux/percpu.h>
59 #include <linux/slab.h>
60 #include <linux/blkdev.h>
61 #include <linux/bvec.h>
62 #include <linux/net.h>
63 #include <net/sock.h>
64 #include <net/af_unix.h>
65 #include <net/scm.h>
66 #include <linux/anon_inodes.h>
67 #include <linux/sched/mm.h>
68 #include <linux/uaccess.h>
69 #include <linux/nospec.h>
70 #include <linux/sizes.h>
71 #include <linux/hugetlb.h>
72 #include <linux/highmem.h>
73 #include <linux/namei.h>
74 #include <linux/fsnotify.h>
75 #include <linux/fadvise.h>
76 #include <linux/eventpoll.h>
77 #include <linux/splice.h>
78 #include <linux/task_work.h>
79 #include <linux/pagemap.h>
80 #include <linux/io_uring.h>
81 
82 #define CREATE_TRACE_POINTS
83 #include <trace/events/io_uring.h>
84 
85 #include <uapi/linux/io_uring.h>
86 
87 #include "internal.h"
88 #include "io-wq.h"
89 
90 #define IORING_MAX_ENTRIES	32768
91 #define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
92 
93 /*
94  * Shift of 9 is 512 entries, or exactly one page on 64-bit archs
95  */
96 #define IORING_FILE_TABLE_SHIFT	9
97 #define IORING_MAX_FILES_TABLE	(1U << IORING_FILE_TABLE_SHIFT)
98 #define IORING_FILE_TABLE_MASK	(IORING_MAX_FILES_TABLE - 1)
99 #define IORING_MAX_FIXED_FILES	(64 * IORING_MAX_FILES_TABLE)
100 #define IORING_MAX_RESTRICTIONS	(IORING_RESTRICTION_LAST + \
101 				 IORING_REGISTER_LAST + IORING_OP_LAST)
102 
103 #define IORING_MAX_REG_BUFFERS	(1U << 14)
104 
105 #define SQE_VALID_FLAGS	(IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK|	\
106 				IOSQE_IO_HARDLINK | IOSQE_ASYNC | \
107 				IOSQE_BUFFER_SELECT)
108 
109 struct io_uring {
110 	u32 head ____cacheline_aligned_in_smp;
111 	u32 tail ____cacheline_aligned_in_smp;
112 };
113 
114 /*
115  * This data is shared with the application through the mmap at offsets
116  * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
117  *
118  * The offsets to the member fields are published through struct
119  * io_sqring_offsets when calling io_uring_setup.
120  */
121 struct io_rings {
122 	/*
123 	 * Head and tail offsets into the ring; the offsets need to be
124 	 * masked to get valid indices.
125 	 *
126 	 * The kernel controls head of the sq ring and the tail of the cq ring,
127 	 * and the application controls tail of the sq ring and the head of the
128 	 * cq ring.
129 	 */
130 	struct io_uring		sq, cq;
131 	/*
132 	 * Bitmasks to apply to head and tail offsets (constant, equals
133 	 * ring_entries - 1)
134 	 */
135 	u32			sq_ring_mask, cq_ring_mask;
136 	/* Ring sizes (constant, power of 2) */
137 	u32			sq_ring_entries, cq_ring_entries;
138 	/*
139 	 * Number of invalid entries dropped by the kernel due to
140 	 * invalid index stored in array
141 	 *
142 	 * Written by the kernel, shouldn't be modified by the
143 	 * application (i.e. get number of "new events" by comparing to
144 	 * cached value).
145 	 *
146 	 * After a new SQ head value was read by the application this
147 	 * counter includes all submissions that were dropped reaching
148 	 * the new SQ head (and possibly more).
149 	 */
150 	u32			sq_dropped;
151 	/*
152 	 * Runtime SQ flags
153 	 *
154 	 * Written by the kernel, shouldn't be modified by the
155 	 * application.
156 	 *
157 	 * The application needs a full memory barrier before checking
158 	 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
159 	 */
160 	u32			sq_flags;
161 	/*
162 	 * Runtime CQ flags
163 	 *
164 	 * Written by the application, shouldn't be modified by the
165 	 * kernel.
166 	 */
167 	u32                     cq_flags;
168 	/*
169 	 * Number of completion events lost because the queue was full;
170 	 * this should be avoided by the application by making sure
171 	 * there are not more requests pending than there is space in
172 	 * the completion queue.
173 	 *
174 	 * Written by the kernel, shouldn't be modified by the
175 	 * application (i.e. get number of "new events" by comparing to
176 	 * cached value).
177 	 *
178 	 * As completion events come in out of order this counter is not
179 	 * ordered with any other data.
180 	 */
181 	u32			cq_overflow;
182 	/*
183 	 * Ring buffer of completion events.
184 	 *
185 	 * The kernel writes completion events fresh every time they are
186 	 * produced, so the application is allowed to modify pending
187 	 * entries.
188 	 */
189 	struct io_uring_cqe	cqes[] ____cacheline_aligned_in_smp;
190 };
191 
192 enum io_uring_cmd_flags {
193 	IO_URING_F_NONBLOCK		= 1,
194 	IO_URING_F_COMPLETE_DEFER	= 2,
195 };
196 
197 struct io_mapped_ubuf {
198 	u64		ubuf;
199 	u64		ubuf_end;
200 	unsigned int	nr_bvecs;
201 	unsigned long	acct_pages;
202 	struct bio_vec	bvec[];
203 };
204 
205 struct io_ring_ctx;
206 
207 struct io_overflow_cqe {
208 	struct io_uring_cqe cqe;
209 	struct list_head list;
210 };
211 
212 struct io_fixed_file {
213 	/* file * with additional FFS_* flags */
214 	unsigned long file_ptr;
215 };
216 
217 struct io_rsrc_put {
218 	struct list_head list;
219 	u64 tag;
220 	union {
221 		void *rsrc;
222 		struct file *file;
223 		struct io_mapped_ubuf *buf;
224 	};
225 };
226 
227 struct io_file_table {
228 	/* two level table */
229 	struct io_fixed_file **files;
230 };
231 
232 struct io_rsrc_node {
233 	struct percpu_ref		refs;
234 	struct list_head		node;
235 	struct list_head		rsrc_list;
236 	struct io_rsrc_data		*rsrc_data;
237 	struct llist_node		llist;
238 	bool				done;
239 };
240 
241 typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
242 
243 struct io_rsrc_data {
244 	struct io_ring_ctx		*ctx;
245 
246 	u64				*tags;
247 	rsrc_put_fn			*do_put;
248 	atomic_t			refs;
249 	struct completion		done;
250 	bool				quiesce;
251 };
252 
253 struct io_buffer {
254 	struct list_head list;
255 	__u64 addr;
256 	__u32 len;
257 	__u16 bid;
258 };
259 
260 struct io_restriction {
261 	DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
262 	DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
263 	u8 sqe_flags_allowed;
264 	u8 sqe_flags_required;
265 	bool registered;
266 };
267 
268 enum {
269 	IO_SQ_THREAD_SHOULD_STOP = 0,
270 	IO_SQ_THREAD_SHOULD_PARK,
271 };
272 
273 struct io_sq_data {
274 	refcount_t		refs;
275 	atomic_t		park_pending;
276 	struct mutex		lock;
277 
278 	/* ctx's that are using this sqd */
279 	struct list_head	ctx_list;
280 
281 	struct task_struct	*thread;
282 	struct wait_queue_head	wait;
283 
284 	unsigned		sq_thread_idle;
285 	int			sq_cpu;
286 	pid_t			task_pid;
287 	pid_t			task_tgid;
288 
289 	unsigned long		state;
290 	struct completion	exited;
291 	struct callback_head	*park_task_work;
292 };
293 
294 #define IO_IOPOLL_BATCH			8
295 #define IO_COMPL_BATCH			32
296 #define IO_REQ_CACHE_SIZE		32
297 #define IO_REQ_ALLOC_BATCH		8
298 
299 struct io_comp_state {
300 	struct io_kiocb		*reqs[IO_COMPL_BATCH];
301 	unsigned int		nr;
302 	unsigned int		locked_free_nr;
303 	/* inline/task_work completion list, under ->uring_lock */
304 	struct list_head	free_list;
305 	/* IRQ completion list, under ->completion_lock */
306 	struct list_head	locked_free_list;
307 };
308 
309 struct io_submit_link {
310 	struct io_kiocb		*head;
311 	struct io_kiocb		*last;
312 };
313 
314 struct io_submit_state {
315 	struct blk_plug		plug;
316 	struct io_submit_link	link;
317 
318 	/*
319 	 * io_kiocb alloc cache
320 	 */
321 	void			*reqs[IO_REQ_CACHE_SIZE];
322 	unsigned int		free_reqs;
323 
324 	bool			plug_started;
325 
326 	/*
327 	 * Batch completion logic
328 	 */
329 	struct io_comp_state	comp;
330 
331 	/*
332 	 * File reference cache
333 	 */
334 	struct file		*file;
335 	unsigned int		fd;
336 	unsigned int		file_refs;
337 	unsigned int		ios_left;
338 };
339 
340 struct io_ring_ctx {
341 	struct {
342 		struct percpu_ref	refs;
343 	} ____cacheline_aligned_in_smp;
344 
345 	struct {
346 		unsigned int		flags;
347 		unsigned int		compat: 1;
348 		unsigned int		drain_next: 1;
349 		unsigned int		eventfd_async: 1;
350 		unsigned int		restricted: 1;
351 
352 		/*
353 		 * Ring buffer of indices into array of io_uring_sqe, which is
354 		 * mmapped by the application using the IORING_OFF_SQES offset.
355 		 *
356 		 * This indirection could e.g. be used to assign fixed
357 		 * io_uring_sqe entries to operations and only submit them to
358 		 * the queue when needed.
359 		 *
360 		 * The kernel modifies neither the indices array nor the entries
361 		 * array.
362 		 */
363 		u32			*sq_array;
364 		unsigned		cached_sq_head;
365 		unsigned		sq_entries;
366 		unsigned		sq_mask;
367 		unsigned		sq_thread_idle;
368 		unsigned		cached_sq_dropped;
369 		unsigned		cached_cq_overflow;
370 		unsigned long		sq_check_overflow;
371 
372 		/* hashed buffered write serialization */
373 		struct io_wq_hash	*hash_map;
374 
375 		struct list_head	defer_list;
376 		struct list_head	timeout_list;
377 		struct list_head	cq_overflow_list;
378 
379 		struct io_uring_sqe	*sq_sqes;
380 	} ____cacheline_aligned_in_smp;
381 
382 	struct {
383 		struct mutex		uring_lock;
384 		wait_queue_head_t	wait;
385 	} ____cacheline_aligned_in_smp;
386 
387 	struct io_submit_state		submit_state;
388 
389 	struct io_rings	*rings;
390 
391 	/* Only used for accounting purposes */
392 	struct mm_struct	*mm_account;
393 
394 	const struct cred	*sq_creds;	/* cred used for __io_sq_thread() */
395 	struct io_sq_data	*sq_data;	/* if using sq thread polling */
396 
397 	struct wait_queue_head	sqo_sq_wait;
398 	struct list_head	sqd_list;
399 
400 	/*
401 	 * If used, fixed file set. Writers must ensure that ->refs is dead,
402 	 * readers must ensure that ->refs is alive as long as the file* is
403 	 * used. Only updated through io_uring_register(2).
404 	 */
405 	struct io_rsrc_data	*file_data;
406 	struct io_file_table	file_table;
407 	unsigned		nr_user_files;
408 
409 	/* if used, fixed mapped user buffers */
410 	struct io_rsrc_data	*buf_data;
411 	unsigned		nr_user_bufs;
412 	struct io_mapped_ubuf	**user_bufs;
413 
414 	struct user_struct	*user;
415 
416 	struct completion	ref_comp;
417 
418 #if defined(CONFIG_UNIX)
419 	struct socket		*ring_sock;
420 #endif
421 
422 	struct xarray		io_buffers;
423 
424 	struct xarray		personalities;
425 	u32			pers_next;
426 
427 	struct {
428 		unsigned		cached_cq_tail;
429 		unsigned		cq_entries;
430 		unsigned		cq_mask;
431 		atomic_t		cq_timeouts;
432 		unsigned		cq_last_tm_flush;
433 		unsigned		cq_extra;
434 		unsigned long		cq_check_overflow;
435 		struct wait_queue_head	cq_wait;
436 		struct fasync_struct	*cq_fasync;
437 		struct eventfd_ctx	*cq_ev_fd;
438 	} ____cacheline_aligned_in_smp;
439 
440 	struct {
441 		spinlock_t		completion_lock;
442 
443 		/*
444 		 * ->iopoll_list is protected by the ctx->uring_lock for
445 		 * io_uring instances that don't use IORING_SETUP_SQPOLL.
446 		 * For SQPOLL, only the single threaded io_sq_thread() will
447 		 * manipulate the list, hence no extra locking is needed there.
448 		 */
449 		struct list_head	iopoll_list;
450 		struct hlist_head	*cancel_hash;
451 		unsigned		cancel_hash_bits;
452 		bool			poll_multi_file;
453 	} ____cacheline_aligned_in_smp;
454 
455 	struct delayed_work		rsrc_put_work;
456 	struct llist_head		rsrc_put_llist;
457 	struct list_head		rsrc_ref_list;
458 	spinlock_t			rsrc_ref_lock;
459 	struct io_rsrc_node		*rsrc_node;
460 	struct io_rsrc_node		*rsrc_backup_node;
461 	struct io_mapped_ubuf		*dummy_ubuf;
462 
463 	struct io_restriction		restrictions;
464 
465 	/* exit task_work */
466 	struct callback_head		*exit_task_work;
467 
468 	/* Keep this last, we don't need it for the fast path */
469 	struct work_struct		exit_work;
470 	struct list_head		tctx_list;
471 };
472 
473 struct io_uring_task {
474 	/* submission side */
475 	struct xarray		xa;
476 	struct wait_queue_head	wait;
477 	const struct io_ring_ctx *last;
478 	struct io_wq		*io_wq;
479 	struct percpu_counter	inflight;
480 	atomic_t		inflight_tracked;
481 	atomic_t		in_idle;
482 
483 	spinlock_t		task_lock;
484 	struct io_wq_work_list	task_list;
485 	unsigned long		task_state;
486 	struct callback_head	task_work;
487 };
488 
489 /*
490  * First field must be the file pointer in all the
491  * iocb unions! See also 'struct kiocb' in <linux/fs.h>
492  */
493 struct io_poll_iocb {
494 	struct file			*file;
495 	struct wait_queue_head		*head;
496 	__poll_t			events;
497 	bool				done;
498 	bool				canceled;
499 	struct wait_queue_entry		wait;
500 };
501 
502 struct io_poll_update {
503 	struct file			*file;
504 	u64				old_user_data;
505 	u64				new_user_data;
506 	__poll_t			events;
507 	bool				update_events;
508 	bool				update_user_data;
509 };
510 
511 struct io_close {
512 	struct file			*file;
513 	int				fd;
514 };
515 
516 struct io_timeout_data {
517 	struct io_kiocb			*req;
518 	struct hrtimer			timer;
519 	struct timespec64		ts;
520 	enum hrtimer_mode		mode;
521 };
522 
523 struct io_accept {
524 	struct file			*file;
525 	struct sockaddr __user		*addr;
526 	int __user			*addr_len;
527 	int				flags;
528 	unsigned long			nofile;
529 };
530 
531 struct io_sync {
532 	struct file			*file;
533 	loff_t				len;
534 	loff_t				off;
535 	int				flags;
536 	int				mode;
537 };
538 
539 struct io_cancel {
540 	struct file			*file;
541 	u64				addr;
542 };
543 
544 struct io_timeout {
545 	struct file			*file;
546 	u32				off;
547 	u32				target_seq;
548 	struct list_head		list;
549 	/* head of the link, used by linked timeouts only */
550 	struct io_kiocb			*head;
551 };
552 
553 struct io_timeout_rem {
554 	struct file			*file;
555 	u64				addr;
556 
557 	/* timeout update */
558 	struct timespec64		ts;
559 	u32				flags;
560 };
561 
562 struct io_rw {
563 	/* NOTE: kiocb has the file as the first member, so don't do it here */
564 	struct kiocb			kiocb;
565 	u64				addr;
566 	u64				len;
567 };
568 
569 struct io_connect {
570 	struct file			*file;
571 	struct sockaddr __user		*addr;
572 	int				addr_len;
573 };
574 
575 struct io_sr_msg {
576 	struct file			*file;
577 	union {
578 		struct compat_msghdr __user	*umsg_compat;
579 		struct user_msghdr __user	*umsg;
580 		void __user			*buf;
581 	};
582 	int				msg_flags;
583 	int				bgid;
584 	size_t				len;
585 	struct io_buffer		*kbuf;
586 };
587 
588 struct io_open {
589 	struct file			*file;
590 	int				dfd;
591 	struct filename			*filename;
592 	struct open_how			how;
593 	unsigned long			nofile;
594 };
595 
596 struct io_rsrc_update {
597 	struct file			*file;
598 	u64				arg;
599 	u32				nr_args;
600 	u32				offset;
601 };
602 
603 struct io_fadvise {
604 	struct file			*file;
605 	u64				offset;
606 	u32				len;
607 	u32				advice;
608 };
609 
610 struct io_madvise {
611 	struct file			*file;
612 	u64				addr;
613 	u32				len;
614 	u32				advice;
615 };
616 
617 struct io_epoll {
618 	struct file			*file;
619 	int				epfd;
620 	int				op;
621 	int				fd;
622 	struct epoll_event		event;
623 };
624 
625 struct io_splice {
626 	struct file			*file_out;
627 	struct file			*file_in;
628 	loff_t				off_out;
629 	loff_t				off_in;
630 	u64				len;
631 	unsigned int			flags;
632 };
633 
634 struct io_provide_buf {
635 	struct file			*file;
636 	__u64				addr;
637 	__u32				len;
638 	__u32				bgid;
639 	__u16				nbufs;
640 	__u16				bid;
641 };
642 
643 struct io_statx {
644 	struct file			*file;
645 	int				dfd;
646 	unsigned int			mask;
647 	unsigned int			flags;
648 	const char __user		*filename;
649 	struct statx __user		*buffer;
650 };
651 
652 struct io_shutdown {
653 	struct file			*file;
654 	int				how;
655 };
656 
657 struct io_rename {
658 	struct file			*file;
659 	int				old_dfd;
660 	int				new_dfd;
661 	struct filename			*oldpath;
662 	struct filename			*newpath;
663 	int				flags;
664 };
665 
666 struct io_unlink {
667 	struct file			*file;
668 	int				dfd;
669 	int				flags;
670 	struct filename			*filename;
671 };
672 
673 struct io_completion {
674 	struct file			*file;
675 	struct list_head		list;
676 	u32				cflags;
677 };
678 
679 struct io_async_connect {
680 	struct sockaddr_storage		address;
681 };
682 
683 struct io_async_msghdr {
684 	struct iovec			fast_iov[UIO_FASTIOV];
685 	/* points to an allocated iov, if NULL we use fast_iov instead */
686 	struct iovec			*free_iov;
687 	struct sockaddr __user		*uaddr;
688 	struct msghdr			msg;
689 	struct sockaddr_storage		addr;
690 };
691 
692 struct io_async_rw {
693 	struct iovec			fast_iov[UIO_FASTIOV];
694 	const struct iovec		*free_iovec;
695 	struct iov_iter			iter;
696 	size_t				bytes_done;
697 	struct wait_page_queue		wpq;
698 };
699 
700 enum {
701 	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
702 	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
703 	REQ_F_LINK_BIT		= IOSQE_IO_LINK_BIT,
704 	REQ_F_HARDLINK_BIT	= IOSQE_IO_HARDLINK_BIT,
705 	REQ_F_FORCE_ASYNC_BIT	= IOSQE_ASYNC_BIT,
706 	REQ_F_BUFFER_SELECT_BIT	= IOSQE_BUFFER_SELECT_BIT,
707 
708 	/* first byte is taken by user flags, shift it to not overlap */
709 	REQ_F_FAIL_LINK_BIT	= 8,
710 	REQ_F_INFLIGHT_BIT,
711 	REQ_F_CUR_POS_BIT,
712 	REQ_F_NOWAIT_BIT,
713 	REQ_F_LINK_TIMEOUT_BIT,
714 	REQ_F_NEED_CLEANUP_BIT,
715 	REQ_F_POLLED_BIT,
716 	REQ_F_BUFFER_SELECTED_BIT,
717 	REQ_F_LTIMEOUT_ACTIVE_BIT,
718 	REQ_F_COMPLETE_INLINE_BIT,
719 	REQ_F_REISSUE_BIT,
720 	REQ_F_DONT_REISSUE_BIT,
721 	/* keep async read/write and isreg together and in order */
722 	REQ_F_ASYNC_READ_BIT,
723 	REQ_F_ASYNC_WRITE_BIT,
724 	REQ_F_ISREG_BIT,
725 
726 	/* not a real bit, just to check we're not overflowing the space */
727 	__REQ_F_LAST_BIT,
728 };
729 
730 enum {
731 	/* ctx owns file */
732 	REQ_F_FIXED_FILE	= BIT(REQ_F_FIXED_FILE_BIT),
733 	/* drain existing IO first */
734 	REQ_F_IO_DRAIN		= BIT(REQ_F_IO_DRAIN_BIT),
735 	/* linked sqes */
736 	REQ_F_LINK		= BIT(REQ_F_LINK_BIT),
737 	/* doesn't sever on completion < 0 */
738 	REQ_F_HARDLINK		= BIT(REQ_F_HARDLINK_BIT),
739 	/* IOSQE_ASYNC */
740 	REQ_F_FORCE_ASYNC	= BIT(REQ_F_FORCE_ASYNC_BIT),
741 	/* IOSQE_BUFFER_SELECT */
742 	REQ_F_BUFFER_SELECT	= BIT(REQ_F_BUFFER_SELECT_BIT),
743 
744 	/* fail rest of links */
745 	REQ_F_FAIL_LINK		= BIT(REQ_F_FAIL_LINK_BIT),
746 	/* on inflight list, should be cancelled and waited on exit reliably */
747 	REQ_F_INFLIGHT		= BIT(REQ_F_INFLIGHT_BIT),
748 	/* read/write uses file position */
749 	REQ_F_CUR_POS		= BIT(REQ_F_CUR_POS_BIT),
750 	/* must not punt to workers */
751 	REQ_F_NOWAIT		= BIT(REQ_F_NOWAIT_BIT),
752 	/* has or had linked timeout */
753 	REQ_F_LINK_TIMEOUT	= BIT(REQ_F_LINK_TIMEOUT_BIT),
754 	/* needs cleanup */
755 	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),
756 	/* already went through poll handler */
757 	REQ_F_POLLED		= BIT(REQ_F_POLLED_BIT),
758 	/* buffer already selected */
759 	REQ_F_BUFFER_SELECTED	= BIT(REQ_F_BUFFER_SELECTED_BIT),
760 	/* linked timeout is active, i.e. prepared by link's head */
761 	REQ_F_LTIMEOUT_ACTIVE	= BIT(REQ_F_LTIMEOUT_ACTIVE_BIT),
762 	/* completion is deferred through io_comp_state */
763 	REQ_F_COMPLETE_INLINE	= BIT(REQ_F_COMPLETE_INLINE_BIT),
764 	/* caller should reissue async */
765 	REQ_F_REISSUE		= BIT(REQ_F_REISSUE_BIT),
766 	/* don't attempt request reissue, see io_rw_reissue() */
767 	REQ_F_DONT_REISSUE	= BIT(REQ_F_DONT_REISSUE_BIT),
768 	/* supports async reads */
769 	REQ_F_ASYNC_READ	= BIT(REQ_F_ASYNC_READ_BIT),
770 	/* supports async writes */
771 	REQ_F_ASYNC_WRITE	= BIT(REQ_F_ASYNC_WRITE_BIT),
772 	/* regular file */
773 	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),
774 };
775 
776 struct async_poll {
777 	struct io_poll_iocb	poll;
778 	struct io_poll_iocb	*double_poll;
779 };
780 
781 struct io_task_work {
782 	struct io_wq_work_node	node;
783 	task_work_func_t	func;
784 };
785 
786 /*
787  * NOTE! Each of the iocb union members has the file pointer
788  * as the first entry in their struct definition. So you can
789  * access the file pointer through any of the sub-structs,
790  * or directly as just 'ki_filp' in this struct.
791  */
792 struct io_kiocb {
793 	union {
794 		struct file		*file;
795 		struct io_rw		rw;
796 		struct io_poll_iocb	poll;
797 		struct io_poll_update	poll_update;
798 		struct io_accept	accept;
799 		struct io_sync		sync;
800 		struct io_cancel	cancel;
801 		struct io_timeout	timeout;
802 		struct io_timeout_rem	timeout_rem;
803 		struct io_connect	connect;
804 		struct io_sr_msg	sr_msg;
805 		struct io_open		open;
806 		struct io_close		close;
807 		struct io_rsrc_update	rsrc_update;
808 		struct io_fadvise	fadvise;
809 		struct io_madvise	madvise;
810 		struct io_epoll		epoll;
811 		struct io_splice	splice;
812 		struct io_provide_buf	pbuf;
813 		struct io_statx		statx;
814 		struct io_shutdown	shutdown;
815 		struct io_rename	rename;
816 		struct io_unlink	unlink;
817 		/* use only after cleaning per-op data, see io_clean_op() */
818 		struct io_completion	compl;
819 	};
820 
821 	/* opcode allocated if it needs to store data for async defer */
822 	void				*async_data;
823 	u8				opcode;
824 	/* polled IO has completed */
825 	u8				iopoll_completed;
826 
827 	u16				buf_index;
828 	u32				result;
829 
830 	struct io_ring_ctx		*ctx;
831 	unsigned int			flags;
832 	atomic_t			refs;
833 	struct task_struct		*task;
834 	u64				user_data;
835 
836 	struct io_kiocb			*link;
837 	struct percpu_ref		*fixed_rsrc_refs;
838 
839 	/* used with ctx->iopoll_list with reads/writes */
840 	struct list_head		inflight_entry;
841 	union {
842 		struct io_task_work	io_task_work;
843 		struct callback_head	task_work;
844 	};
845 	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
846 	struct hlist_node		hash_node;
847 	struct async_poll		*apoll;
848 	struct io_wq_work		work;
849 	/* store used ubuf, so we can prevent reloading */
850 	struct io_mapped_ubuf		*imu;
851 };
852 
853 struct io_tctx_node {
854 	struct list_head	ctx_node;
855 	struct task_struct	*task;
856 	struct io_ring_ctx	*ctx;
857 };
858 
859 struct io_defer_entry {
860 	struct list_head	list;
861 	struct io_kiocb		*req;
862 	u32			seq;
863 };
864 
865 struct io_op_def {
866 	/* needs req->file assigned */
867 	unsigned		needs_file : 1;
868 	/* hash wq insertion if file is a regular file */
869 	unsigned		hash_reg_file : 1;
870 	/* unbound wq insertion if file is a non-regular file */
871 	unsigned		unbound_nonreg_file : 1;
872 	/* opcode is not supported by this kernel */
873 	unsigned		not_supported : 1;
874 	/* set if opcode supports polled "wait" */
875 	unsigned		pollin : 1;
876 	unsigned		pollout : 1;
877 	/* op supports buffer selection */
878 	unsigned		buffer_select : 1;
879 	/* do prep async if is going to be punted */
880 	unsigned		needs_async_setup : 1;
881 	/* should block plug */
882 	unsigned		plug : 1;
883 	/* size of async data needed, if any */
884 	unsigned short		async_size;
885 };
886 
887 static const struct io_op_def io_op_defs[] = {
888 	[IORING_OP_NOP] = {},
889 	[IORING_OP_READV] = {
890 		.needs_file		= 1,
891 		.unbound_nonreg_file	= 1,
892 		.pollin			= 1,
893 		.buffer_select		= 1,
894 		.needs_async_setup	= 1,
895 		.plug			= 1,
896 		.async_size		= sizeof(struct io_async_rw),
897 	},
898 	[IORING_OP_WRITEV] = {
899 		.needs_file		= 1,
900 		.hash_reg_file		= 1,
901 		.unbound_nonreg_file	= 1,
902 		.pollout		= 1,
903 		.needs_async_setup	= 1,
904 		.plug			= 1,
905 		.async_size		= sizeof(struct io_async_rw),
906 	},
907 	[IORING_OP_FSYNC] = {
908 		.needs_file		= 1,
909 	},
910 	[IORING_OP_READ_FIXED] = {
911 		.needs_file		= 1,
912 		.unbound_nonreg_file	= 1,
913 		.pollin			= 1,
914 		.plug			= 1,
915 		.async_size		= sizeof(struct io_async_rw),
916 	},
917 	[IORING_OP_WRITE_FIXED] = {
918 		.needs_file		= 1,
919 		.hash_reg_file		= 1,
920 		.unbound_nonreg_file	= 1,
921 		.pollout		= 1,
922 		.plug			= 1,
923 		.async_size		= sizeof(struct io_async_rw),
924 	},
925 	[IORING_OP_POLL_ADD] = {
926 		.needs_file		= 1,
927 		.unbound_nonreg_file	= 1,
928 	},
929 	[IORING_OP_POLL_REMOVE] = {},
930 	[IORING_OP_SYNC_FILE_RANGE] = {
931 		.needs_file		= 1,
932 	},
933 	[IORING_OP_SENDMSG] = {
934 		.needs_file		= 1,
935 		.unbound_nonreg_file	= 1,
936 		.pollout		= 1,
937 		.needs_async_setup	= 1,
938 		.async_size		= sizeof(struct io_async_msghdr),
939 	},
940 	[IORING_OP_RECVMSG] = {
941 		.needs_file		= 1,
942 		.unbound_nonreg_file	= 1,
943 		.pollin			= 1,
944 		.buffer_select		= 1,
945 		.needs_async_setup	= 1,
946 		.async_size		= sizeof(struct io_async_msghdr),
947 	},
948 	[IORING_OP_TIMEOUT] = {
949 		.async_size		= sizeof(struct io_timeout_data),
950 	},
951 	[IORING_OP_TIMEOUT_REMOVE] = {
952 		/* used by timeout updates' prep() */
953 	},
954 	[IORING_OP_ACCEPT] = {
955 		.needs_file		= 1,
956 		.unbound_nonreg_file	= 1,
957 		.pollin			= 1,
958 	},
959 	[IORING_OP_ASYNC_CANCEL] = {},
960 	[IORING_OP_LINK_TIMEOUT] = {
961 		.async_size		= sizeof(struct io_timeout_data),
962 	},
963 	[IORING_OP_CONNECT] = {
964 		.needs_file		= 1,
965 		.unbound_nonreg_file	= 1,
966 		.pollout		= 1,
967 		.needs_async_setup	= 1,
968 		.async_size		= sizeof(struct io_async_connect),
969 	},
970 	[IORING_OP_FALLOCATE] = {
971 		.needs_file		= 1,
972 	},
973 	[IORING_OP_OPENAT] = {},
974 	[IORING_OP_CLOSE] = {},
975 	[IORING_OP_FILES_UPDATE] = {},
976 	[IORING_OP_STATX] = {},
977 	[IORING_OP_READ] = {
978 		.needs_file		= 1,
979 		.unbound_nonreg_file	= 1,
980 		.pollin			= 1,
981 		.buffer_select		= 1,
982 		.plug			= 1,
983 		.async_size		= sizeof(struct io_async_rw),
984 	},
985 	[IORING_OP_WRITE] = {
986 		.needs_file		= 1,
987 		.unbound_nonreg_file	= 1,
988 		.pollout		= 1,
989 		.plug			= 1,
990 		.async_size		= sizeof(struct io_async_rw),
991 	},
992 	[IORING_OP_FADVISE] = {
993 		.needs_file		= 1,
994 	},
995 	[IORING_OP_MADVISE] = {},
996 	[IORING_OP_SEND] = {
997 		.needs_file		= 1,
998 		.unbound_nonreg_file	= 1,
999 		.pollout		= 1,
1000 	},
1001 	[IORING_OP_RECV] = {
1002 		.needs_file		= 1,
1003 		.unbound_nonreg_file	= 1,
1004 		.pollin			= 1,
1005 		.buffer_select		= 1,
1006 	},
1007 	[IORING_OP_OPENAT2] = {
1008 	},
1009 	[IORING_OP_EPOLL_CTL] = {
1010 		.unbound_nonreg_file	= 1,
1011 	},
1012 	[IORING_OP_SPLICE] = {
1013 		.needs_file		= 1,
1014 		.hash_reg_file		= 1,
1015 		.unbound_nonreg_file	= 1,
1016 	},
1017 	[IORING_OP_PROVIDE_BUFFERS] = {},
1018 	[IORING_OP_REMOVE_BUFFERS] = {},
1019 	[IORING_OP_TEE] = {
1020 		.needs_file		= 1,
1021 		.hash_reg_file		= 1,
1022 		.unbound_nonreg_file	= 1,
1023 	},
1024 	[IORING_OP_SHUTDOWN] = {
1025 		.needs_file		= 1,
1026 	},
1027 	[IORING_OP_RENAMEAT] = {},
1028 	[IORING_OP_UNLINKAT] = {},
1029 };
1030 
1031 static bool io_disarm_next(struct io_kiocb *req);
1032 static void io_uring_del_task_file(unsigned long index);
1033 static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
1034 					 struct task_struct *task,
1035 					 struct files_struct *files);
1036 static void io_uring_cancel_sqpoll(struct io_sq_data *sqd);
1037 static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx);
1038 
1039 static bool io_cqring_fill_event(struct io_ring_ctx *ctx, u64 user_data,
1040 				 long res, unsigned int cflags);
1041 static void io_put_req(struct io_kiocb *req);
1042 static void io_put_req_deferred(struct io_kiocb *req, int nr);
1043 static void io_dismantle_req(struct io_kiocb *req);
1044 static void io_put_task(struct task_struct *task, int nr);
1045 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
1046 static void io_queue_linked_timeout(struct io_kiocb *req);
1047 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
1048 				     struct io_uring_rsrc_update2 *up,
1049 				     unsigned nr_args);
1050 static void io_clean_op(struct io_kiocb *req);
1051 static struct file *io_file_get(struct io_submit_state *state,
1052 				struct io_kiocb *req, int fd, bool fixed);
1053 static void __io_queue_sqe(struct io_kiocb *req);
1054 static void io_rsrc_put_work(struct work_struct *work);
1055 
1056 static void io_req_task_queue(struct io_kiocb *req);
1057 static void io_submit_flush_completions(struct io_comp_state *cs,
1058 					struct io_ring_ctx *ctx);
1059 static bool io_poll_remove_waitqs(struct io_kiocb *req);
1060 static int io_req_prep_async(struct io_kiocb *req);
1061 
1062 static struct kmem_cache *req_cachep;
1063 
1064 static const struct file_operations io_uring_fops;
1065 
io_uring_get_socket(struct file * file)1066 struct sock *io_uring_get_socket(struct file *file)
1067 {
1068 #if defined(CONFIG_UNIX)
1069 	if (file->f_op == &io_uring_fops) {
1070 		struct io_ring_ctx *ctx = file->private_data;
1071 
1072 		return ctx->ring_sock->sk;
1073 	}
1074 #endif
1075 	return NULL;
1076 }
1077 EXPORT_SYMBOL(io_uring_get_socket);
1078 
1079 #define io_for_each_link(pos, head) \
1080 	for (pos = (head); pos; pos = pos->link)
1081 
io_req_set_rsrc_node(struct io_kiocb * req)1082 static inline void io_req_set_rsrc_node(struct io_kiocb *req)
1083 {
1084 	struct io_ring_ctx *ctx = req->ctx;
1085 
1086 	if (!req->fixed_rsrc_refs) {
1087 		req->fixed_rsrc_refs = &ctx->rsrc_node->refs;
1088 		percpu_ref_get(req->fixed_rsrc_refs);
1089 	}
1090 }
1091 
io_refs_resurrect(struct percpu_ref * ref,struct completion * compl)1092 static void io_refs_resurrect(struct percpu_ref *ref, struct completion *compl)
1093 {
1094 	bool got = percpu_ref_tryget(ref);
1095 
1096 	/* already at zero, wait for ->release() */
1097 	if (!got)
1098 		wait_for_completion(compl);
1099 	percpu_ref_resurrect(ref);
1100 	if (got)
1101 		percpu_ref_put(ref);
1102 }
1103 
io_match_task(struct io_kiocb * head,struct task_struct * task,struct files_struct * files)1104 static bool io_match_task(struct io_kiocb *head,
1105 			  struct task_struct *task,
1106 			  struct files_struct *files)
1107 {
1108 	struct io_kiocb *req;
1109 
1110 	if (task && head->task != task)
1111 		return false;
1112 	if (!files)
1113 		return true;
1114 
1115 	io_for_each_link(req, head) {
1116 		if (req->flags & REQ_F_INFLIGHT)
1117 			return true;
1118 	}
1119 	return false;
1120 }
1121 
req_set_fail_links(struct io_kiocb * req)1122 static inline void req_set_fail_links(struct io_kiocb *req)
1123 {
1124 	if (req->flags & REQ_F_LINK)
1125 		req->flags |= REQ_F_FAIL_LINK;
1126 }
1127 
io_ring_ctx_ref_free(struct percpu_ref * ref)1128 static void io_ring_ctx_ref_free(struct percpu_ref *ref)
1129 {
1130 	struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
1131 
1132 	complete(&ctx->ref_comp);
1133 }
1134 
io_is_timeout_noseq(struct io_kiocb * req)1135 static inline bool io_is_timeout_noseq(struct io_kiocb *req)
1136 {
1137 	return !req->timeout.off;
1138 }
1139 
io_ring_ctx_alloc(struct io_uring_params * p)1140 static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
1141 {
1142 	struct io_ring_ctx *ctx;
1143 	int hash_bits;
1144 
1145 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1146 	if (!ctx)
1147 		return NULL;
1148 
1149 	/*
1150 	 * Use 5 bits less than the max cq entries, that should give us around
1151 	 * 32 entries per hash list if totally full and uniformly spread.
1152 	 */
1153 	hash_bits = ilog2(p->cq_entries);
1154 	hash_bits -= 5;
1155 	if (hash_bits <= 0)
1156 		hash_bits = 1;
1157 	ctx->cancel_hash_bits = hash_bits;
1158 	ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
1159 					GFP_KERNEL);
1160 	if (!ctx->cancel_hash)
1161 		goto err;
1162 	__hash_init(ctx->cancel_hash, 1U << hash_bits);
1163 
1164 	ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
1165 	if (!ctx->dummy_ubuf)
1166 		goto err;
1167 	/* set invalid range, so io_import_fixed() fails meeting it */
1168 	ctx->dummy_ubuf->ubuf = -1UL;
1169 
1170 	if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
1171 			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
1172 		goto err;
1173 
1174 	ctx->flags = p->flags;
1175 	init_waitqueue_head(&ctx->sqo_sq_wait);
1176 	INIT_LIST_HEAD(&ctx->sqd_list);
1177 	init_waitqueue_head(&ctx->cq_wait);
1178 	INIT_LIST_HEAD(&ctx->cq_overflow_list);
1179 	init_completion(&ctx->ref_comp);
1180 	xa_init_flags(&ctx->io_buffers, XA_FLAGS_ALLOC1);
1181 	xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
1182 	mutex_init(&ctx->uring_lock);
1183 	init_waitqueue_head(&ctx->wait);
1184 	spin_lock_init(&ctx->completion_lock);
1185 	INIT_LIST_HEAD(&ctx->iopoll_list);
1186 	INIT_LIST_HEAD(&ctx->defer_list);
1187 	INIT_LIST_HEAD(&ctx->timeout_list);
1188 	spin_lock_init(&ctx->rsrc_ref_lock);
1189 	INIT_LIST_HEAD(&ctx->rsrc_ref_list);
1190 	INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
1191 	init_llist_head(&ctx->rsrc_put_llist);
1192 	INIT_LIST_HEAD(&ctx->tctx_list);
1193 	INIT_LIST_HEAD(&ctx->submit_state.comp.free_list);
1194 	INIT_LIST_HEAD(&ctx->submit_state.comp.locked_free_list);
1195 	return ctx;
1196 err:
1197 	kfree(ctx->dummy_ubuf);
1198 	kfree(ctx->cancel_hash);
1199 	kfree(ctx);
1200 	return NULL;
1201 }
1202 
req_need_defer(struct io_kiocb * req,u32 seq)1203 static bool req_need_defer(struct io_kiocb *req, u32 seq)
1204 {
1205 	if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
1206 		struct io_ring_ctx *ctx = req->ctx;
1207 
1208 		return seq + ctx->cq_extra != ctx->cached_cq_tail
1209 				+ READ_ONCE(ctx->cached_cq_overflow);
1210 	}
1211 
1212 	return false;
1213 }
1214 
io_req_track_inflight(struct io_kiocb * req)1215 static void io_req_track_inflight(struct io_kiocb *req)
1216 {
1217 	if (!(req->flags & REQ_F_INFLIGHT)) {
1218 		req->flags |= REQ_F_INFLIGHT;
1219 		atomic_inc(&current->io_uring->inflight_tracked);
1220 	}
1221 }
1222 
io_prep_async_work(struct io_kiocb * req)1223 static void io_prep_async_work(struct io_kiocb *req)
1224 {
1225 	const struct io_op_def *def = &io_op_defs[req->opcode];
1226 	struct io_ring_ctx *ctx = req->ctx;
1227 
1228 	if (!req->work.creds)
1229 		req->work.creds = get_current_cred();
1230 
1231 	req->work.list.next = NULL;
1232 	req->work.flags = 0;
1233 	if (req->flags & REQ_F_FORCE_ASYNC)
1234 		req->work.flags |= IO_WQ_WORK_CONCURRENT;
1235 
1236 	if (req->flags & REQ_F_ISREG) {
1237 		if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
1238 			io_wq_hash_work(&req->work, file_inode(req->file));
1239 	} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
1240 		if (def->unbound_nonreg_file)
1241 			req->work.flags |= IO_WQ_WORK_UNBOUND;
1242 	}
1243 
1244 	switch (req->opcode) {
1245 	case IORING_OP_SPLICE:
1246 	case IORING_OP_TEE:
1247 		if (!S_ISREG(file_inode(req->splice.file_in)->i_mode))
1248 			req->work.flags |= IO_WQ_WORK_UNBOUND;
1249 		break;
1250 	}
1251 }
1252 
io_prep_async_link(struct io_kiocb * req)1253 static void io_prep_async_link(struct io_kiocb *req)
1254 {
1255 	struct io_kiocb *cur;
1256 
1257 	io_for_each_link(cur, req)
1258 		io_prep_async_work(cur);
1259 }
1260 
io_queue_async_work(struct io_kiocb * req)1261 static void io_queue_async_work(struct io_kiocb *req)
1262 {
1263 	struct io_ring_ctx *ctx = req->ctx;
1264 	struct io_kiocb *link = io_prep_linked_timeout(req);
1265 	struct io_uring_task *tctx = req->task->io_uring;
1266 
1267 	BUG_ON(!tctx);
1268 	BUG_ON(!tctx->io_wq);
1269 
1270 	/* init ->work of the whole link before punting */
1271 	io_prep_async_link(req);
1272 	trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
1273 					&req->work, req->flags);
1274 	io_wq_enqueue(tctx->io_wq, &req->work);
1275 	if (link)
1276 		io_queue_linked_timeout(link);
1277 }
1278 
io_kill_timeout(struct io_kiocb * req,int status)1279 static void io_kill_timeout(struct io_kiocb *req, int status)
1280 	__must_hold(&req->ctx->completion_lock)
1281 {
1282 	struct io_timeout_data *io = req->async_data;
1283 
1284 	if (hrtimer_try_to_cancel(&io->timer) != -1) {
1285 		atomic_set(&req->ctx->cq_timeouts,
1286 			atomic_read(&req->ctx->cq_timeouts) + 1);
1287 		list_del_init(&req->timeout.list);
1288 		io_cqring_fill_event(req->ctx, req->user_data, status, 0);
1289 		io_put_req_deferred(req, 1);
1290 	}
1291 }
1292 
__io_queue_deferred(struct io_ring_ctx * ctx)1293 static void __io_queue_deferred(struct io_ring_ctx *ctx)
1294 {
1295 	do {
1296 		struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
1297 						struct io_defer_entry, list);
1298 
1299 		if (req_need_defer(de->req, de->seq))
1300 			break;
1301 		list_del_init(&de->list);
1302 		io_req_task_queue(de->req);
1303 		kfree(de);
1304 	} while (!list_empty(&ctx->defer_list));
1305 }
1306 
io_flush_timeouts(struct io_ring_ctx * ctx)1307 static void io_flush_timeouts(struct io_ring_ctx *ctx)
1308 {
1309 	u32 seq;
1310 
1311 	if (list_empty(&ctx->timeout_list))
1312 		return;
1313 
1314 	seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
1315 
1316 	do {
1317 		u32 events_needed, events_got;
1318 		struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
1319 						struct io_kiocb, timeout.list);
1320 
1321 		if (io_is_timeout_noseq(req))
1322 			break;
1323 
1324 		/*
1325 		 * Since seq can easily wrap around over time, subtract
1326 		 * the last seq at which timeouts were flushed before comparing.
1327 		 * Assuming not more than 2^31-1 events have happened since,
1328 		 * these subtractions won't have wrapped, so we can check if
1329 		 * target is in [last_seq, current_seq] by comparing the two.
1330 		 */
1331 		events_needed = req->timeout.target_seq - ctx->cq_last_tm_flush;
1332 		events_got = seq - ctx->cq_last_tm_flush;
1333 		if (events_got < events_needed)
1334 			break;
1335 
1336 		list_del_init(&req->timeout.list);
1337 		io_kill_timeout(req, 0);
1338 	} while (!list_empty(&ctx->timeout_list));
1339 
1340 	ctx->cq_last_tm_flush = seq;
1341 }
1342 
io_commit_cqring(struct io_ring_ctx * ctx)1343 static void io_commit_cqring(struct io_ring_ctx *ctx)
1344 {
1345 	io_flush_timeouts(ctx);
1346 
1347 	/* order cqe stores with ring update */
1348 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
1349 
1350 	if (unlikely(!list_empty(&ctx->defer_list)))
1351 		__io_queue_deferred(ctx);
1352 }
1353 
io_sqring_full(struct io_ring_ctx * ctx)1354 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
1355 {
1356 	struct io_rings *r = ctx->rings;
1357 
1358 	return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == r->sq_ring_entries;
1359 }
1360 
__io_cqring_events(struct io_ring_ctx * ctx)1361 static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
1362 {
1363 	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
1364 }
1365 
io_get_cqring(struct io_ring_ctx * ctx)1366 static inline struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
1367 {
1368 	struct io_rings *rings = ctx->rings;
1369 	unsigned tail;
1370 
1371 	/*
1372 	 * writes to the cq entry need to come after reading head; the
1373 	 * control dependency is enough as we're using WRITE_ONCE to
1374 	 * fill the cq entry
1375 	 */
1376 	if (__io_cqring_events(ctx) == rings->cq_ring_entries)
1377 		return NULL;
1378 
1379 	tail = ctx->cached_cq_tail++;
1380 	return &rings->cqes[tail & ctx->cq_mask];
1381 }
1382 
io_should_trigger_evfd(struct io_ring_ctx * ctx)1383 static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx)
1384 {
1385 	if (likely(!ctx->cq_ev_fd))
1386 		return false;
1387 	if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
1388 		return false;
1389 	return !ctx->eventfd_async || io_wq_current_is_worker();
1390 }
1391 
io_cqring_ev_posted(struct io_ring_ctx * ctx)1392 static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
1393 {
1394 	/* see waitqueue_active() comment */
1395 	smp_mb();
1396 
1397 	if (waitqueue_active(&ctx->wait))
1398 		wake_up(&ctx->wait);
1399 	if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait))
1400 		wake_up(&ctx->sq_data->wait);
1401 	if (io_should_trigger_evfd(ctx))
1402 		eventfd_signal(ctx->cq_ev_fd, 1);
1403 	if (waitqueue_active(&ctx->cq_wait)) {
1404 		wake_up_interruptible(&ctx->cq_wait);
1405 		kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
1406 	}
1407 }
1408 
io_cqring_ev_posted_iopoll(struct io_ring_ctx * ctx)1409 static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
1410 {
1411 	/* see waitqueue_active() comment */
1412 	smp_mb();
1413 
1414 	if (ctx->flags & IORING_SETUP_SQPOLL) {
1415 		if (waitqueue_active(&ctx->wait))
1416 			wake_up(&ctx->wait);
1417 	}
1418 	if (io_should_trigger_evfd(ctx))
1419 		eventfd_signal(ctx->cq_ev_fd, 1);
1420 	if (waitqueue_active(&ctx->cq_wait)) {
1421 		wake_up_interruptible(&ctx->cq_wait);
1422 		kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
1423 	}
1424 }
1425 
1426 /* Returns true if there are no backlogged entries after the flush */
__io_cqring_overflow_flush(struct io_ring_ctx * ctx,bool force)1427 static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
1428 {
1429 	struct io_rings *rings = ctx->rings;
1430 	unsigned long flags;
1431 	bool all_flushed, posted;
1432 
1433 	if (!force && __io_cqring_events(ctx) == rings->cq_ring_entries)
1434 		return false;
1435 
1436 	posted = false;
1437 	spin_lock_irqsave(&ctx->completion_lock, flags);
1438 	while (!list_empty(&ctx->cq_overflow_list)) {
1439 		struct io_uring_cqe *cqe = io_get_cqring(ctx);
1440 		struct io_overflow_cqe *ocqe;
1441 
1442 		if (!cqe && !force)
1443 			break;
1444 		ocqe = list_first_entry(&ctx->cq_overflow_list,
1445 					struct io_overflow_cqe, list);
1446 		if (cqe)
1447 			memcpy(cqe, &ocqe->cqe, sizeof(*cqe));
1448 		else
1449 			WRITE_ONCE(ctx->rings->cq_overflow,
1450 				   ++ctx->cached_cq_overflow);
1451 		posted = true;
1452 		list_del(&ocqe->list);
1453 		kfree(ocqe);
1454 	}
1455 
1456 	all_flushed = list_empty(&ctx->cq_overflow_list);
1457 	if (all_flushed) {
1458 		clear_bit(0, &ctx->sq_check_overflow);
1459 		clear_bit(0, &ctx->cq_check_overflow);
1460 		ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
1461 	}
1462 
1463 	if (posted)
1464 		io_commit_cqring(ctx);
1465 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
1466 	if (posted)
1467 		io_cqring_ev_posted(ctx);
1468 	return all_flushed;
1469 }
1470 
io_cqring_overflow_flush(struct io_ring_ctx * ctx,bool force)1471 static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
1472 {
1473 	bool ret = true;
1474 
1475 	if (test_bit(0, &ctx->cq_check_overflow)) {
1476 		/* iopoll syncs against uring_lock, not completion_lock */
1477 		if (ctx->flags & IORING_SETUP_IOPOLL)
1478 			mutex_lock(&ctx->uring_lock);
1479 		ret = __io_cqring_overflow_flush(ctx, force);
1480 		if (ctx->flags & IORING_SETUP_IOPOLL)
1481 			mutex_unlock(&ctx->uring_lock);
1482 	}
1483 
1484 	return ret;
1485 }
1486 
1487 /*
1488  * Shamelessly stolen from the mm implementation of page reference checking,
1489  * see commit f958d7b528b1 for details.
1490  */
1491 #define req_ref_zero_or_close_to_overflow(req)	\
1492 	((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u)
1493 
req_ref_inc_not_zero(struct io_kiocb * req)1494 static inline bool req_ref_inc_not_zero(struct io_kiocb *req)
1495 {
1496 	return atomic_inc_not_zero(&req->refs);
1497 }
1498 
req_ref_sub_and_test(struct io_kiocb * req,int refs)1499 static inline bool req_ref_sub_and_test(struct io_kiocb *req, int refs)
1500 {
1501 	WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
1502 	return atomic_sub_and_test(refs, &req->refs);
1503 }
1504 
req_ref_put_and_test(struct io_kiocb * req)1505 static inline bool req_ref_put_and_test(struct io_kiocb *req)
1506 {
1507 	WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
1508 	return atomic_dec_and_test(&req->refs);
1509 }
1510 
req_ref_put(struct io_kiocb * req)1511 static inline void req_ref_put(struct io_kiocb *req)
1512 {
1513 	WARN_ON_ONCE(req_ref_put_and_test(req));
1514 }
1515 
req_ref_get(struct io_kiocb * req)1516 static inline void req_ref_get(struct io_kiocb *req)
1517 {
1518 	WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
1519 	atomic_inc(&req->refs);
1520 }
1521 
io_cqring_event_overflow(struct io_ring_ctx * ctx,u64 user_data,long res,unsigned int cflags)1522 static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
1523 				     long res, unsigned int cflags)
1524 {
1525 	struct io_overflow_cqe *ocqe;
1526 
1527 	ocqe = kmalloc(sizeof(*ocqe), GFP_ATOMIC | __GFP_ACCOUNT);
1528 	if (!ocqe) {
1529 		/*
1530 		 * If we're in ring overflow flush mode, or in task cancel mode,
1531 		 * or cannot allocate an overflow entry, then we need to drop it
1532 		 * on the floor.
1533 		 */
1534 		WRITE_ONCE(ctx->rings->cq_overflow, ++ctx->cached_cq_overflow);
1535 		return false;
1536 	}
1537 	if (list_empty(&ctx->cq_overflow_list)) {
1538 		set_bit(0, &ctx->sq_check_overflow);
1539 		set_bit(0, &ctx->cq_check_overflow);
1540 		ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
1541 	}
1542 	ocqe->cqe.user_data = user_data;
1543 	ocqe->cqe.res = res;
1544 	ocqe->cqe.flags = cflags;
1545 	list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
1546 	return true;
1547 }
1548 
__io_cqring_fill_event(struct io_ring_ctx * ctx,u64 user_data,long res,unsigned int cflags)1549 static inline bool __io_cqring_fill_event(struct io_ring_ctx *ctx, u64 user_data,
1550 					  long res, unsigned int cflags)
1551 {
1552 	struct io_uring_cqe *cqe;
1553 
1554 	trace_io_uring_complete(ctx, user_data, res, cflags);
1555 
1556 	/*
1557 	 * If we can't get a cq entry, userspace overflowed the
1558 	 * submission (by quite a lot). Increment the overflow count in
1559 	 * the ring.
1560 	 */
1561 	cqe = io_get_cqring(ctx);
1562 	if (likely(cqe)) {
1563 		WRITE_ONCE(cqe->user_data, user_data);
1564 		WRITE_ONCE(cqe->res, res);
1565 		WRITE_ONCE(cqe->flags, cflags);
1566 		return true;
1567 	}
1568 	return io_cqring_event_overflow(ctx, user_data, res, cflags);
1569 }
1570 
1571 /* not as hot to bloat with inlining */
io_cqring_fill_event(struct io_ring_ctx * ctx,u64 user_data,long res,unsigned int cflags)1572 static noinline bool io_cqring_fill_event(struct io_ring_ctx *ctx, u64 user_data,
1573 					  long res, unsigned int cflags)
1574 {
1575 	return __io_cqring_fill_event(ctx, user_data, res, cflags);
1576 }
1577 
io_req_complete_post(struct io_kiocb * req,long res,unsigned int cflags)1578 static void io_req_complete_post(struct io_kiocb *req, long res,
1579 				 unsigned int cflags)
1580 {
1581 	struct io_ring_ctx *ctx = req->ctx;
1582 	unsigned long flags;
1583 
1584 	spin_lock_irqsave(&ctx->completion_lock, flags);
1585 	__io_cqring_fill_event(ctx, req->user_data, res, cflags);
1586 	/*
1587 	 * If we're the last reference to this request, add to our locked
1588 	 * free_list cache.
1589 	 */
1590 	if (req_ref_put_and_test(req)) {
1591 		struct io_comp_state *cs = &ctx->submit_state.comp;
1592 
1593 		if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) {
1594 			if (req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_FAIL_LINK))
1595 				io_disarm_next(req);
1596 			if (req->link) {
1597 				io_req_task_queue(req->link);
1598 				req->link = NULL;
1599 			}
1600 		}
1601 		io_dismantle_req(req);
1602 		io_put_task(req->task, 1);
1603 		list_add(&req->compl.list, &cs->locked_free_list);
1604 		cs->locked_free_nr++;
1605 	} else {
1606 		if (!percpu_ref_tryget(&ctx->refs))
1607 			req = NULL;
1608 	}
1609 	io_commit_cqring(ctx);
1610 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
1611 
1612 	if (req) {
1613 		io_cqring_ev_posted(ctx);
1614 		percpu_ref_put(&ctx->refs);
1615 	}
1616 }
1617 
io_req_needs_clean(struct io_kiocb * req)1618 static inline bool io_req_needs_clean(struct io_kiocb *req)
1619 {
1620 	return req->flags & (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP |
1621 				REQ_F_POLLED | REQ_F_INFLIGHT);
1622 }
1623 
io_req_complete_state(struct io_kiocb * req,long res,unsigned int cflags)1624 static void io_req_complete_state(struct io_kiocb *req, long res,
1625 				  unsigned int cflags)
1626 {
1627 	if (io_req_needs_clean(req))
1628 		io_clean_op(req);
1629 	req->result = res;
1630 	req->compl.cflags = cflags;
1631 	req->flags |= REQ_F_COMPLETE_INLINE;
1632 }
1633 
__io_req_complete(struct io_kiocb * req,unsigned issue_flags,long res,unsigned cflags)1634 static inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags,
1635 				     long res, unsigned cflags)
1636 {
1637 	if (issue_flags & IO_URING_F_COMPLETE_DEFER)
1638 		io_req_complete_state(req, res, cflags);
1639 	else
1640 		io_req_complete_post(req, res, cflags);
1641 }
1642 
io_req_complete(struct io_kiocb * req,long res)1643 static inline void io_req_complete(struct io_kiocb *req, long res)
1644 {
1645 	__io_req_complete(req, 0, res, 0);
1646 }
1647 
io_req_complete_failed(struct io_kiocb * req,long res)1648 static void io_req_complete_failed(struct io_kiocb *req, long res)
1649 {
1650 	req_set_fail_links(req);
1651 	io_put_req(req);
1652 	io_req_complete_post(req, res, 0);
1653 }
1654 
io_flush_cached_locked_reqs(struct io_ring_ctx * ctx,struct io_comp_state * cs)1655 static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
1656 					struct io_comp_state *cs)
1657 {
1658 	spin_lock_irq(&ctx->completion_lock);
1659 	list_splice_init(&cs->locked_free_list, &cs->free_list);
1660 	cs->locked_free_nr = 0;
1661 	spin_unlock_irq(&ctx->completion_lock);
1662 }
1663 
1664 /* Returns true IFF there are requests in the cache */
io_flush_cached_reqs(struct io_ring_ctx * ctx)1665 static bool io_flush_cached_reqs(struct io_ring_ctx *ctx)
1666 {
1667 	struct io_submit_state *state = &ctx->submit_state;
1668 	struct io_comp_state *cs = &state->comp;
1669 	int nr;
1670 
1671 	/*
1672 	 * If we have more than a batch's worth of requests in our IRQ side
1673 	 * locked cache, grab the lock and move them over to our submission
1674 	 * side cache.
1675 	 */
1676 	if (READ_ONCE(cs->locked_free_nr) > IO_COMPL_BATCH)
1677 		io_flush_cached_locked_reqs(ctx, cs);
1678 
1679 	nr = state->free_reqs;
1680 	while (!list_empty(&cs->free_list)) {
1681 		struct io_kiocb *req = list_first_entry(&cs->free_list,
1682 						struct io_kiocb, compl.list);
1683 
1684 		list_del(&req->compl.list);
1685 		state->reqs[nr++] = req;
1686 		if (nr == ARRAY_SIZE(state->reqs))
1687 			break;
1688 	}
1689 
1690 	state->free_reqs = nr;
1691 	return nr != 0;
1692 }
1693 
io_alloc_req(struct io_ring_ctx * ctx)1694 static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
1695 {
1696 	struct io_submit_state *state = &ctx->submit_state;
1697 
1698 	BUILD_BUG_ON(IO_REQ_ALLOC_BATCH > ARRAY_SIZE(state->reqs));
1699 
1700 	if (!state->free_reqs) {
1701 		gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
1702 		int ret;
1703 
1704 		if (io_flush_cached_reqs(ctx))
1705 			goto got_req;
1706 
1707 		ret = kmem_cache_alloc_bulk(req_cachep, gfp, IO_REQ_ALLOC_BATCH,
1708 					    state->reqs);
1709 
1710 		/*
1711 		 * Bulk alloc is all-or-nothing. If we fail to get a batch,
1712 		 * retry single alloc to be on the safe side.
1713 		 */
1714 		if (unlikely(ret <= 0)) {
1715 			state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
1716 			if (!state->reqs[0])
1717 				return NULL;
1718 			ret = 1;
1719 		}
1720 		state->free_reqs = ret;
1721 	}
1722 got_req:
1723 	state->free_reqs--;
1724 	return state->reqs[state->free_reqs];
1725 }
1726 
io_put_file(struct file * file)1727 static inline void io_put_file(struct file *file)
1728 {
1729 	if (file)
1730 		fput(file);
1731 }
1732 
io_dismantle_req(struct io_kiocb * req)1733 static void io_dismantle_req(struct io_kiocb *req)
1734 {
1735 	unsigned int flags = req->flags;
1736 
1737 	if (io_req_needs_clean(req))
1738 		io_clean_op(req);
1739 	if (!(flags & REQ_F_FIXED_FILE))
1740 		io_put_file(req->file);
1741 	if (req->fixed_rsrc_refs)
1742 		percpu_ref_put(req->fixed_rsrc_refs);
1743 	if (req->async_data)
1744 		kfree(req->async_data);
1745 	if (req->work.creds) {
1746 		put_cred(req->work.creds);
1747 		req->work.creds = NULL;
1748 	}
1749 }
1750 
1751 /* must to be called somewhat shortly after putting a request */
io_put_task(struct task_struct * task,int nr)1752 static inline void io_put_task(struct task_struct *task, int nr)
1753 {
1754 	struct io_uring_task *tctx = task->io_uring;
1755 
1756 	percpu_counter_sub(&tctx->inflight, nr);
1757 	if (unlikely(atomic_read(&tctx->in_idle)))
1758 		wake_up(&tctx->wait);
1759 	put_task_struct_many(task, nr);
1760 }
1761 
__io_free_req(struct io_kiocb * req)1762 static void __io_free_req(struct io_kiocb *req)
1763 {
1764 	struct io_ring_ctx *ctx = req->ctx;
1765 
1766 	io_dismantle_req(req);
1767 	io_put_task(req->task, 1);
1768 
1769 	kmem_cache_free(req_cachep, req);
1770 	percpu_ref_put(&ctx->refs);
1771 }
1772 
io_remove_next_linked(struct io_kiocb * req)1773 static inline void io_remove_next_linked(struct io_kiocb *req)
1774 {
1775 	struct io_kiocb *nxt = req->link;
1776 
1777 	req->link = nxt->link;
1778 	nxt->link = NULL;
1779 }
1780 
io_kill_linked_timeout(struct io_kiocb * req)1781 static bool io_kill_linked_timeout(struct io_kiocb *req)
1782 	__must_hold(&req->ctx->completion_lock)
1783 {
1784 	struct io_kiocb *link = req->link;
1785 
1786 	/*
1787 	 * Can happen if a linked timeout fired and link had been like
1788 	 * req -> link t-out -> link t-out [-> ...]
1789 	 */
1790 	if (link && (link->flags & REQ_F_LTIMEOUT_ACTIVE)) {
1791 		struct io_timeout_data *io = link->async_data;
1792 
1793 		io_remove_next_linked(req);
1794 		link->timeout.head = NULL;
1795 		if (hrtimer_try_to_cancel(&io->timer) != -1) {
1796 			io_cqring_fill_event(link->ctx, link->user_data,
1797 					     -ECANCELED, 0);
1798 			io_put_req_deferred(link, 1);
1799 			return true;
1800 		}
1801 	}
1802 	return false;
1803 }
1804 
io_fail_links(struct io_kiocb * req)1805 static void io_fail_links(struct io_kiocb *req)
1806 	__must_hold(&req->ctx->completion_lock)
1807 {
1808 	struct io_kiocb *nxt, *link = req->link;
1809 
1810 	req->link = NULL;
1811 	while (link) {
1812 		nxt = link->link;
1813 		link->link = NULL;
1814 
1815 		trace_io_uring_fail_link(req, link);
1816 		io_cqring_fill_event(link->ctx, link->user_data, -ECANCELED, 0);
1817 		io_put_req_deferred(link, 2);
1818 		link = nxt;
1819 	}
1820 }
1821 
io_disarm_next(struct io_kiocb * req)1822 static bool io_disarm_next(struct io_kiocb *req)
1823 	__must_hold(&req->ctx->completion_lock)
1824 {
1825 	bool posted = false;
1826 
1827 	if (likely(req->flags & REQ_F_LINK_TIMEOUT))
1828 		posted = io_kill_linked_timeout(req);
1829 	if (unlikely((req->flags & REQ_F_FAIL_LINK) &&
1830 		     !(req->flags & REQ_F_HARDLINK))) {
1831 		posted |= (req->link != NULL);
1832 		io_fail_links(req);
1833 	}
1834 	return posted;
1835 }
1836 
__io_req_find_next(struct io_kiocb * req)1837 static struct io_kiocb *__io_req_find_next(struct io_kiocb *req)
1838 {
1839 	struct io_kiocb *nxt;
1840 
1841 	/*
1842 	 * If LINK is set, we have dependent requests in this chain. If we
1843 	 * didn't fail this request, queue the first one up, moving any other
1844 	 * dependencies to the next request. In case of failure, fail the rest
1845 	 * of the chain.
1846 	 */
1847 	if (req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_FAIL_LINK)) {
1848 		struct io_ring_ctx *ctx = req->ctx;
1849 		unsigned long flags;
1850 		bool posted;
1851 
1852 		spin_lock_irqsave(&ctx->completion_lock, flags);
1853 		posted = io_disarm_next(req);
1854 		if (posted)
1855 			io_commit_cqring(req->ctx);
1856 		spin_unlock_irqrestore(&ctx->completion_lock, flags);
1857 		if (posted)
1858 			io_cqring_ev_posted(ctx);
1859 	}
1860 	nxt = req->link;
1861 	req->link = NULL;
1862 	return nxt;
1863 }
1864 
io_req_find_next(struct io_kiocb * req)1865 static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
1866 {
1867 	if (likely(!(req->flags & (REQ_F_LINK|REQ_F_HARDLINK))))
1868 		return NULL;
1869 	return __io_req_find_next(req);
1870 }
1871 
ctx_flush_and_put(struct io_ring_ctx * ctx)1872 static void ctx_flush_and_put(struct io_ring_ctx *ctx)
1873 {
1874 	if (!ctx)
1875 		return;
1876 	if (ctx->submit_state.comp.nr) {
1877 		mutex_lock(&ctx->uring_lock);
1878 		io_submit_flush_completions(&ctx->submit_state.comp, ctx);
1879 		mutex_unlock(&ctx->uring_lock);
1880 	}
1881 	percpu_ref_put(&ctx->refs);
1882 }
1883 
__tctx_task_work(struct io_uring_task * tctx)1884 static bool __tctx_task_work(struct io_uring_task *tctx)
1885 {
1886 	struct io_ring_ctx *ctx = NULL;
1887 	struct io_wq_work_list list;
1888 	struct io_wq_work_node *node;
1889 
1890 	if (wq_list_empty(&tctx->task_list))
1891 		return false;
1892 
1893 	spin_lock_irq(&tctx->task_lock);
1894 	list = tctx->task_list;
1895 	INIT_WQ_LIST(&tctx->task_list);
1896 	spin_unlock_irq(&tctx->task_lock);
1897 
1898 	node = list.first;
1899 	while (node) {
1900 		struct io_wq_work_node *next = node->next;
1901 		struct io_kiocb *req;
1902 
1903 		req = container_of(node, struct io_kiocb, io_task_work.node);
1904 		if (req->ctx != ctx) {
1905 			ctx_flush_and_put(ctx);
1906 			ctx = req->ctx;
1907 			percpu_ref_get(&ctx->refs);
1908 		}
1909 
1910 		req->task_work.func(&req->task_work);
1911 		node = next;
1912 	}
1913 
1914 	ctx_flush_and_put(ctx);
1915 	return list.first != NULL;
1916 }
1917 
tctx_task_work(struct callback_head * cb)1918 static void tctx_task_work(struct callback_head *cb)
1919 {
1920 	struct io_uring_task *tctx = container_of(cb, struct io_uring_task, task_work);
1921 
1922 	clear_bit(0, &tctx->task_state);
1923 
1924 	while (__tctx_task_work(tctx))
1925 		cond_resched();
1926 }
1927 
io_req_task_work_add(struct io_kiocb * req)1928 static int io_req_task_work_add(struct io_kiocb *req)
1929 {
1930 	struct task_struct *tsk = req->task;
1931 	struct io_uring_task *tctx = tsk->io_uring;
1932 	enum task_work_notify_mode notify;
1933 	struct io_wq_work_node *node, *prev;
1934 	unsigned long flags;
1935 	int ret = 0;
1936 
1937 	if (unlikely(tsk->flags & PF_EXITING))
1938 		return -ESRCH;
1939 
1940 	WARN_ON_ONCE(!tctx);
1941 
1942 	spin_lock_irqsave(&tctx->task_lock, flags);
1943 	wq_list_add_tail(&req->io_task_work.node, &tctx->task_list);
1944 	spin_unlock_irqrestore(&tctx->task_lock, flags);
1945 
1946 	/* task_work already pending, we're done */
1947 	if (test_bit(0, &tctx->task_state) ||
1948 	    test_and_set_bit(0, &tctx->task_state))
1949 		return 0;
1950 
1951 	/*
1952 	 * SQPOLL kernel thread doesn't need notification, just a wakeup. For
1953 	 * all other cases, use TWA_SIGNAL unconditionally to ensure we're
1954 	 * processing task_work. There's no reliable way to tell if TWA_RESUME
1955 	 * will do the job.
1956 	 */
1957 	notify = (req->ctx->flags & IORING_SETUP_SQPOLL) ? TWA_NONE : TWA_SIGNAL;
1958 
1959 	if (!task_work_add(tsk, &tctx->task_work, notify)) {
1960 		wake_up_process(tsk);
1961 		return 0;
1962 	}
1963 
1964 	/*
1965 	 * Slow path - we failed, find and delete work. if the work is not
1966 	 * in the list, it got run and we're fine.
1967 	 */
1968 	spin_lock_irqsave(&tctx->task_lock, flags);
1969 	wq_list_for_each(node, prev, &tctx->task_list) {
1970 		if (&req->io_task_work.node == node) {
1971 			wq_list_del(&tctx->task_list, node, prev);
1972 			ret = 1;
1973 			break;
1974 		}
1975 	}
1976 	spin_unlock_irqrestore(&tctx->task_lock, flags);
1977 	clear_bit(0, &tctx->task_state);
1978 	return ret;
1979 }
1980 
io_run_task_work_head(struct callback_head ** work_head)1981 static bool io_run_task_work_head(struct callback_head **work_head)
1982 {
1983 	struct callback_head *work, *next;
1984 	bool executed = false;
1985 
1986 	do {
1987 		work = xchg(work_head, NULL);
1988 		if (!work)
1989 			break;
1990 
1991 		do {
1992 			next = work->next;
1993 			work->func(work);
1994 			work = next;
1995 			cond_resched();
1996 		} while (work);
1997 		executed = true;
1998 	} while (1);
1999 
2000 	return executed;
2001 }
2002 
io_task_work_add_head(struct callback_head ** work_head,struct callback_head * task_work)2003 static void io_task_work_add_head(struct callback_head **work_head,
2004 				  struct callback_head *task_work)
2005 {
2006 	struct callback_head *head;
2007 
2008 	do {
2009 		head = READ_ONCE(*work_head);
2010 		task_work->next = head;
2011 	} while (cmpxchg(work_head, head, task_work) != head);
2012 }
2013 
io_req_task_work_add_fallback(struct io_kiocb * req,task_work_func_t cb)2014 static void io_req_task_work_add_fallback(struct io_kiocb *req,
2015 					  task_work_func_t cb)
2016 {
2017 	init_task_work(&req->task_work, cb);
2018 	io_task_work_add_head(&req->ctx->exit_task_work, &req->task_work);
2019 }
2020 
io_req_task_cancel(struct callback_head * cb)2021 static void io_req_task_cancel(struct callback_head *cb)
2022 {
2023 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2024 	struct io_ring_ctx *ctx = req->ctx;
2025 
2026 	/* ctx is guaranteed to stay alive while we hold uring_lock */
2027 	mutex_lock(&ctx->uring_lock);
2028 	io_req_complete_failed(req, req->result);
2029 	mutex_unlock(&ctx->uring_lock);
2030 }
2031 
__io_req_task_submit(struct io_kiocb * req)2032 static void __io_req_task_submit(struct io_kiocb *req)
2033 {
2034 	struct io_ring_ctx *ctx = req->ctx;
2035 
2036 	/* ctx stays valid until unlock, even if we drop all ours ctx->refs */
2037 	mutex_lock(&ctx->uring_lock);
2038 	if (!(current->flags & PF_EXITING) && !current->in_execve)
2039 		__io_queue_sqe(req);
2040 	else
2041 		io_req_complete_failed(req, -EFAULT);
2042 	mutex_unlock(&ctx->uring_lock);
2043 }
2044 
io_req_task_submit(struct callback_head * cb)2045 static void io_req_task_submit(struct callback_head *cb)
2046 {
2047 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2048 
2049 	__io_req_task_submit(req);
2050 }
2051 
io_req_task_queue_fail(struct io_kiocb * req,int ret)2052 static void io_req_task_queue_fail(struct io_kiocb *req, int ret)
2053 {
2054 	req->result = ret;
2055 	req->task_work.func = io_req_task_cancel;
2056 
2057 	if (unlikely(io_req_task_work_add(req)))
2058 		io_req_task_work_add_fallback(req, io_req_task_cancel);
2059 }
2060 
io_req_task_queue(struct io_kiocb * req)2061 static void io_req_task_queue(struct io_kiocb *req)
2062 {
2063 	req->task_work.func = io_req_task_submit;
2064 
2065 	if (unlikely(io_req_task_work_add(req)))
2066 		io_req_task_queue_fail(req, -ECANCELED);
2067 }
2068 
io_queue_next(struct io_kiocb * req)2069 static inline void io_queue_next(struct io_kiocb *req)
2070 {
2071 	struct io_kiocb *nxt = io_req_find_next(req);
2072 
2073 	if (nxt)
2074 		io_req_task_queue(nxt);
2075 }
2076 
io_free_req(struct io_kiocb * req)2077 static void io_free_req(struct io_kiocb *req)
2078 {
2079 	io_queue_next(req);
2080 	__io_free_req(req);
2081 }
2082 
2083 struct req_batch {
2084 	struct task_struct	*task;
2085 	int			task_refs;
2086 	int			ctx_refs;
2087 };
2088 
io_init_req_batch(struct req_batch * rb)2089 static inline void io_init_req_batch(struct req_batch *rb)
2090 {
2091 	rb->task_refs = 0;
2092 	rb->ctx_refs = 0;
2093 	rb->task = NULL;
2094 }
2095 
io_req_free_batch_finish(struct io_ring_ctx * ctx,struct req_batch * rb)2096 static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
2097 				     struct req_batch *rb)
2098 {
2099 	if (rb->task)
2100 		io_put_task(rb->task, rb->task_refs);
2101 	if (rb->ctx_refs)
2102 		percpu_ref_put_many(&ctx->refs, rb->ctx_refs);
2103 }
2104 
io_req_free_batch(struct req_batch * rb,struct io_kiocb * req,struct io_submit_state * state)2105 static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req,
2106 			      struct io_submit_state *state)
2107 {
2108 	io_queue_next(req);
2109 	io_dismantle_req(req);
2110 
2111 	if (req->task != rb->task) {
2112 		if (rb->task)
2113 			io_put_task(rb->task, rb->task_refs);
2114 		rb->task = req->task;
2115 		rb->task_refs = 0;
2116 	}
2117 	rb->task_refs++;
2118 	rb->ctx_refs++;
2119 
2120 	if (state->free_reqs != ARRAY_SIZE(state->reqs))
2121 		state->reqs[state->free_reqs++] = req;
2122 	else
2123 		list_add(&req->compl.list, &state->comp.free_list);
2124 }
2125 
io_submit_flush_completions(struct io_comp_state * cs,struct io_ring_ctx * ctx)2126 static void io_submit_flush_completions(struct io_comp_state *cs,
2127 					struct io_ring_ctx *ctx)
2128 {
2129 	int i, nr = cs->nr;
2130 	struct io_kiocb *req;
2131 	struct req_batch rb;
2132 
2133 	io_init_req_batch(&rb);
2134 	spin_lock_irq(&ctx->completion_lock);
2135 	for (i = 0; i < nr; i++) {
2136 		req = cs->reqs[i];
2137 		__io_cqring_fill_event(ctx, req->user_data, req->result,
2138 					req->compl.cflags);
2139 	}
2140 	io_commit_cqring(ctx);
2141 	spin_unlock_irq(&ctx->completion_lock);
2142 
2143 	io_cqring_ev_posted(ctx);
2144 	for (i = 0; i < nr; i++) {
2145 		req = cs->reqs[i];
2146 
2147 		/* submission and completion refs */
2148 		if (req_ref_sub_and_test(req, 2))
2149 			io_req_free_batch(&rb, req, &ctx->submit_state);
2150 	}
2151 
2152 	io_req_free_batch_finish(ctx, &rb);
2153 	cs->nr = 0;
2154 }
2155 
2156 /*
2157  * Drop reference to request, return next in chain (if there is one) if this
2158  * was the last reference to this request.
2159  */
io_put_req_find_next(struct io_kiocb * req)2160 static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
2161 {
2162 	struct io_kiocb *nxt = NULL;
2163 
2164 	if (req_ref_put_and_test(req)) {
2165 		nxt = io_req_find_next(req);
2166 		__io_free_req(req);
2167 	}
2168 	return nxt;
2169 }
2170 
io_put_req(struct io_kiocb * req)2171 static inline void io_put_req(struct io_kiocb *req)
2172 {
2173 	if (req_ref_put_and_test(req))
2174 		io_free_req(req);
2175 }
2176 
io_put_req_deferred_cb(struct callback_head * cb)2177 static void io_put_req_deferred_cb(struct callback_head *cb)
2178 {
2179 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2180 
2181 	io_free_req(req);
2182 }
2183 
io_free_req_deferred(struct io_kiocb * req)2184 static void io_free_req_deferred(struct io_kiocb *req)
2185 {
2186 	req->task_work.func = io_put_req_deferred_cb;
2187 	if (unlikely(io_req_task_work_add(req)))
2188 		io_req_task_work_add_fallback(req, io_put_req_deferred_cb);
2189 }
2190 
io_put_req_deferred(struct io_kiocb * req,int refs)2191 static inline void io_put_req_deferred(struct io_kiocb *req, int refs)
2192 {
2193 	if (req_ref_sub_and_test(req, refs))
2194 		io_free_req_deferred(req);
2195 }
2196 
io_cqring_events(struct io_ring_ctx * ctx)2197 static unsigned io_cqring_events(struct io_ring_ctx *ctx)
2198 {
2199 	/* See comment at the top of this file */
2200 	smp_rmb();
2201 	return __io_cqring_events(ctx);
2202 }
2203 
io_sqring_entries(struct io_ring_ctx * ctx)2204 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
2205 {
2206 	struct io_rings *rings = ctx->rings;
2207 
2208 	/* make sure SQ entry isn't read before tail */
2209 	return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
2210 }
2211 
io_put_kbuf(struct io_kiocb * req,struct io_buffer * kbuf)2212 static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf)
2213 {
2214 	unsigned int cflags;
2215 
2216 	cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
2217 	cflags |= IORING_CQE_F_BUFFER;
2218 	req->flags &= ~REQ_F_BUFFER_SELECTED;
2219 	kfree(kbuf);
2220 	return cflags;
2221 }
2222 
io_put_rw_kbuf(struct io_kiocb * req)2223 static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
2224 {
2225 	struct io_buffer *kbuf;
2226 
2227 	kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
2228 	return io_put_kbuf(req, kbuf);
2229 }
2230 
io_run_task_work(void)2231 static inline bool io_run_task_work(void)
2232 {
2233 	/*
2234 	 * Not safe to run on exiting task, and the task_work handling will
2235 	 * not add work to such a task.
2236 	 */
2237 	if (unlikely(current->flags & PF_EXITING))
2238 		return false;
2239 	if (current->task_works) {
2240 		__set_current_state(TASK_RUNNING);
2241 		task_work_run();
2242 		return true;
2243 	}
2244 
2245 	return false;
2246 }
2247 
2248 /*
2249  * Find and free completed poll iocbs
2250  */
io_iopoll_complete(struct io_ring_ctx * ctx,unsigned int * nr_events,struct list_head * done)2251 static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
2252 			       struct list_head *done)
2253 {
2254 	struct req_batch rb;
2255 	struct io_kiocb *req;
2256 
2257 	/* order with ->result store in io_complete_rw_iopoll() */
2258 	smp_rmb();
2259 
2260 	io_init_req_batch(&rb);
2261 	while (!list_empty(done)) {
2262 		int cflags = 0;
2263 
2264 		req = list_first_entry(done, struct io_kiocb, inflight_entry);
2265 		list_del(&req->inflight_entry);
2266 
2267 		if (READ_ONCE(req->result) == -EAGAIN &&
2268 		    !(req->flags & REQ_F_DONT_REISSUE)) {
2269 			req->iopoll_completed = 0;
2270 			req_ref_get(req);
2271 			io_queue_async_work(req);
2272 			continue;
2273 		}
2274 
2275 		if (req->flags & REQ_F_BUFFER_SELECTED)
2276 			cflags = io_put_rw_kbuf(req);
2277 
2278 		__io_cqring_fill_event(ctx, req->user_data, req->result, cflags);
2279 		(*nr_events)++;
2280 
2281 		if (req_ref_put_and_test(req))
2282 			io_req_free_batch(&rb, req, &ctx->submit_state);
2283 	}
2284 
2285 	io_commit_cqring(ctx);
2286 	io_cqring_ev_posted_iopoll(ctx);
2287 	io_req_free_batch_finish(ctx, &rb);
2288 }
2289 
io_do_iopoll(struct io_ring_ctx * ctx,unsigned int * nr_events,long min)2290 static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
2291 			long min)
2292 {
2293 	struct io_kiocb *req, *tmp;
2294 	LIST_HEAD(done);
2295 	bool spin;
2296 	int ret;
2297 
2298 	/*
2299 	 * Only spin for completions if we don't have multiple devices hanging
2300 	 * off our complete list, and we're under the requested amount.
2301 	 */
2302 	spin = !ctx->poll_multi_file && *nr_events < min;
2303 
2304 	ret = 0;
2305 	list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) {
2306 		struct kiocb *kiocb = &req->rw.kiocb;
2307 
2308 		/*
2309 		 * Move completed and retryable entries to our local lists.
2310 		 * If we find a request that requires polling, break out
2311 		 * and complete those lists first, if we have entries there.
2312 		 */
2313 		if (READ_ONCE(req->iopoll_completed)) {
2314 			list_move_tail(&req->inflight_entry, &done);
2315 			continue;
2316 		}
2317 		if (!list_empty(&done))
2318 			break;
2319 
2320 		ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
2321 		if (ret < 0)
2322 			break;
2323 
2324 		/* iopoll may have completed current req */
2325 		if (READ_ONCE(req->iopoll_completed))
2326 			list_move_tail(&req->inflight_entry, &done);
2327 
2328 		if (ret && spin)
2329 			spin = false;
2330 		ret = 0;
2331 	}
2332 
2333 	if (!list_empty(&done))
2334 		io_iopoll_complete(ctx, nr_events, &done);
2335 
2336 	return ret;
2337 }
2338 
2339 /*
2340  * We can't just wait for polled events to come to us, we have to actively
2341  * find and complete them.
2342  */
io_iopoll_try_reap_events(struct io_ring_ctx * ctx)2343 static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
2344 {
2345 	if (!(ctx->flags & IORING_SETUP_IOPOLL))
2346 		return;
2347 
2348 	mutex_lock(&ctx->uring_lock);
2349 	while (!list_empty(&ctx->iopoll_list)) {
2350 		unsigned int nr_events = 0;
2351 
2352 		io_do_iopoll(ctx, &nr_events, 0);
2353 
2354 		/* let it sleep and repeat later if can't complete a request */
2355 		if (nr_events == 0)
2356 			break;
2357 		/*
2358 		 * Ensure we allow local-to-the-cpu processing to take place,
2359 		 * in this case we need to ensure that we reap all events.
2360 		 * Also let task_work, etc. to progress by releasing the mutex
2361 		 */
2362 		if (need_resched()) {
2363 			mutex_unlock(&ctx->uring_lock);
2364 			cond_resched();
2365 			mutex_lock(&ctx->uring_lock);
2366 		}
2367 	}
2368 	mutex_unlock(&ctx->uring_lock);
2369 }
2370 
io_iopoll_check(struct io_ring_ctx * ctx,long min)2371 static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
2372 {
2373 	unsigned int nr_events = 0;
2374 	int ret = 0;
2375 
2376 	/*
2377 	 * We disallow the app entering submit/complete with polling, but we
2378 	 * still need to lock the ring to prevent racing with polled issue
2379 	 * that got punted to a workqueue.
2380 	 */
2381 	mutex_lock(&ctx->uring_lock);
2382 	/*
2383 	 * Don't enter poll loop if we already have events pending.
2384 	 * If we do, we can potentially be spinning for commands that
2385 	 * already triggered a CQE (eg in error).
2386 	 */
2387 	if (test_bit(0, &ctx->cq_check_overflow))
2388 		__io_cqring_overflow_flush(ctx, false);
2389 	if (io_cqring_events(ctx))
2390 		goto out;
2391 	do {
2392 		/*
2393 		 * If a submit got punted to a workqueue, we can have the
2394 		 * application entering polling for a command before it gets
2395 		 * issued. That app will hold the uring_lock for the duration
2396 		 * of the poll right here, so we need to take a breather every
2397 		 * now and then to ensure that the issue has a chance to add
2398 		 * the poll to the issued list. Otherwise we can spin here
2399 		 * forever, while the workqueue is stuck trying to acquire the
2400 		 * very same mutex.
2401 		 */
2402 		if (list_empty(&ctx->iopoll_list)) {
2403 			mutex_unlock(&ctx->uring_lock);
2404 			io_run_task_work();
2405 			mutex_lock(&ctx->uring_lock);
2406 
2407 			if (list_empty(&ctx->iopoll_list))
2408 				break;
2409 		}
2410 		ret = io_do_iopoll(ctx, &nr_events, min);
2411 	} while (!ret && nr_events < min && !need_resched());
2412 out:
2413 	mutex_unlock(&ctx->uring_lock);
2414 	return ret;
2415 }
2416 
kiocb_end_write(struct io_kiocb * req)2417 static void kiocb_end_write(struct io_kiocb *req)
2418 {
2419 	/*
2420 	 * Tell lockdep we inherited freeze protection from submission
2421 	 * thread.
2422 	 */
2423 	if (req->flags & REQ_F_ISREG) {
2424 		struct super_block *sb = file_inode(req->file)->i_sb;
2425 
2426 		__sb_writers_acquired(sb, SB_FREEZE_WRITE);
2427 		sb_end_write(sb);
2428 	}
2429 }
2430 
2431 #ifdef CONFIG_BLOCK
io_resubmit_prep(struct io_kiocb * req)2432 static bool io_resubmit_prep(struct io_kiocb *req)
2433 {
2434 	struct io_async_rw *rw = req->async_data;
2435 
2436 	if (!rw)
2437 		return !io_req_prep_async(req);
2438 	/* may have left rw->iter inconsistent on -EIOCBQUEUED */
2439 	iov_iter_revert(&rw->iter, req->result - iov_iter_count(&rw->iter));
2440 	return true;
2441 }
2442 
io_rw_should_reissue(struct io_kiocb * req)2443 static bool io_rw_should_reissue(struct io_kiocb *req)
2444 {
2445 	umode_t mode = file_inode(req->file)->i_mode;
2446 	struct io_ring_ctx *ctx = req->ctx;
2447 
2448 	if (!S_ISBLK(mode) && !S_ISREG(mode))
2449 		return false;
2450 	if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
2451 	    !(ctx->flags & IORING_SETUP_IOPOLL)))
2452 		return false;
2453 	/*
2454 	 * If ref is dying, we might be running poll reap from the exit work.
2455 	 * Don't attempt to reissue from that path, just let it fail with
2456 	 * -EAGAIN.
2457 	 */
2458 	if (percpu_ref_is_dying(&ctx->refs))
2459 		return false;
2460 	return true;
2461 }
2462 #else
io_resubmit_prep(struct io_kiocb * req)2463 static bool io_resubmit_prep(struct io_kiocb *req)
2464 {
2465 	return false;
2466 }
io_rw_should_reissue(struct io_kiocb * req)2467 static bool io_rw_should_reissue(struct io_kiocb *req)
2468 {
2469 	return false;
2470 }
2471 #endif
2472 
__io_complete_rw(struct io_kiocb * req,long res,long res2,unsigned int issue_flags)2473 static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
2474 			     unsigned int issue_flags)
2475 {
2476 	int cflags = 0;
2477 
2478 	if (req->rw.kiocb.ki_flags & IOCB_WRITE)
2479 		kiocb_end_write(req);
2480 	if (res != req->result) {
2481 		if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
2482 		    io_rw_should_reissue(req)) {
2483 			req->flags |= REQ_F_REISSUE;
2484 			return;
2485 		}
2486 		req_set_fail_links(req);
2487 	}
2488 	if (req->flags & REQ_F_BUFFER_SELECTED)
2489 		cflags = io_put_rw_kbuf(req);
2490 	__io_req_complete(req, issue_flags, res, cflags);
2491 }
2492 
io_complete_rw(struct kiocb * kiocb,long res,long res2)2493 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
2494 {
2495 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2496 
2497 	__io_complete_rw(req, res, res2, 0);
2498 }
2499 
io_complete_rw_iopoll(struct kiocb * kiocb,long res,long res2)2500 static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
2501 {
2502 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2503 
2504 	if (kiocb->ki_flags & IOCB_WRITE)
2505 		kiocb_end_write(req);
2506 	if (unlikely(res != req->result)) {
2507 		if (!(res == -EAGAIN && io_rw_should_reissue(req) &&
2508 		    io_resubmit_prep(req))) {
2509 			req_set_fail_links(req);
2510 			req->flags |= REQ_F_DONT_REISSUE;
2511 		}
2512 	}
2513 
2514 	WRITE_ONCE(req->result, res);
2515 	/* order with io_iopoll_complete() checking ->result */
2516 	smp_wmb();
2517 	WRITE_ONCE(req->iopoll_completed, 1);
2518 }
2519 
2520 /*
2521  * After the iocb has been issued, it's safe to be found on the poll list.
2522  * Adding the kiocb to the list AFTER submission ensures that we don't
2523  * find it from a io_do_iopoll() thread before the issuer is done
2524  * accessing the kiocb cookie.
2525  */
io_iopoll_req_issued(struct io_kiocb * req,bool in_async)2526 static void io_iopoll_req_issued(struct io_kiocb *req, bool in_async)
2527 {
2528 	struct io_ring_ctx *ctx = req->ctx;
2529 
2530 	/*
2531 	 * Track whether we have multiple files in our lists. This will impact
2532 	 * how we do polling eventually, not spinning if we're on potentially
2533 	 * different devices.
2534 	 */
2535 	if (list_empty(&ctx->iopoll_list)) {
2536 		ctx->poll_multi_file = false;
2537 	} else if (!ctx->poll_multi_file) {
2538 		struct io_kiocb *list_req;
2539 
2540 		list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb,
2541 						inflight_entry);
2542 		if (list_req->file != req->file)
2543 			ctx->poll_multi_file = true;
2544 	}
2545 
2546 	/*
2547 	 * For fast devices, IO may have already completed. If it has, add
2548 	 * it to the front so we find it first.
2549 	 */
2550 	if (READ_ONCE(req->iopoll_completed))
2551 		list_add(&req->inflight_entry, &ctx->iopoll_list);
2552 	else
2553 		list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
2554 
2555 	/*
2556 	 * If IORING_SETUP_SQPOLL is enabled, sqes are either handled in sq thread
2557 	 * task context or in io worker task context. If current task context is
2558 	 * sq thread, we don't need to check whether should wake up sq thread.
2559 	 */
2560 	if (in_async && (ctx->flags & IORING_SETUP_SQPOLL) &&
2561 	    wq_has_sleeper(&ctx->sq_data->wait))
2562 		wake_up(&ctx->sq_data->wait);
2563 }
2564 
io_state_file_put(struct io_submit_state * state)2565 static inline void io_state_file_put(struct io_submit_state *state)
2566 {
2567 	if (state->file_refs) {
2568 		fput_many(state->file, state->file_refs);
2569 		state->file_refs = 0;
2570 	}
2571 }
2572 
2573 /*
2574  * Get as many references to a file as we have IOs left in this submission,
2575  * assuming most submissions are for one file, or at least that each file
2576  * has more than one submission.
2577  */
__io_file_get(struct io_submit_state * state,int fd)2578 static struct file *__io_file_get(struct io_submit_state *state, int fd)
2579 {
2580 	if (!state)
2581 		return fget(fd);
2582 
2583 	if (state->file_refs) {
2584 		if (state->fd == fd) {
2585 			state->file_refs--;
2586 			return state->file;
2587 		}
2588 		io_state_file_put(state);
2589 	}
2590 	state->file = fget_many(fd, state->ios_left);
2591 	if (unlikely(!state->file))
2592 		return NULL;
2593 
2594 	state->fd = fd;
2595 	state->file_refs = state->ios_left - 1;
2596 	return state->file;
2597 }
2598 
io_bdev_nowait(struct block_device * bdev)2599 static bool io_bdev_nowait(struct block_device *bdev)
2600 {
2601 	return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
2602 }
2603 
2604 /*
2605  * If we tracked the file through the SCM inflight mechanism, we could support
2606  * any file. For now, just ensure that anything potentially problematic is done
2607  * inline.
2608  */
__io_file_supports_async(struct file * file,int rw)2609 static bool __io_file_supports_async(struct file *file, int rw)
2610 {
2611 	umode_t mode = file_inode(file)->i_mode;
2612 
2613 	if (S_ISBLK(mode)) {
2614 		if (IS_ENABLED(CONFIG_BLOCK) &&
2615 		    io_bdev_nowait(I_BDEV(file->f_mapping->host)))
2616 			return true;
2617 		return false;
2618 	}
2619 	if (S_ISCHR(mode) || S_ISSOCK(mode))
2620 		return true;
2621 	if (S_ISREG(mode)) {
2622 		if (IS_ENABLED(CONFIG_BLOCK) &&
2623 		    io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
2624 		    file->f_op != &io_uring_fops)
2625 			return true;
2626 		return false;
2627 	}
2628 
2629 	/* any ->read/write should understand O_NONBLOCK */
2630 	if (file->f_flags & O_NONBLOCK)
2631 		return true;
2632 
2633 	if (!(file->f_mode & FMODE_NOWAIT))
2634 		return false;
2635 
2636 	if (rw == READ)
2637 		return file->f_op->read_iter != NULL;
2638 
2639 	return file->f_op->write_iter != NULL;
2640 }
2641 
io_file_supports_async(struct io_kiocb * req,int rw)2642 static bool io_file_supports_async(struct io_kiocb *req, int rw)
2643 {
2644 	if (rw == READ && (req->flags & REQ_F_ASYNC_READ))
2645 		return true;
2646 	else if (rw == WRITE && (req->flags & REQ_F_ASYNC_WRITE))
2647 		return true;
2648 
2649 	return __io_file_supports_async(req->file, rw);
2650 }
2651 
io_prep_rw(struct io_kiocb * req,const struct io_uring_sqe * sqe)2652 static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2653 {
2654 	struct io_ring_ctx *ctx = req->ctx;
2655 	struct kiocb *kiocb = &req->rw.kiocb;
2656 	struct file *file = req->file;
2657 	unsigned ioprio;
2658 	int ret;
2659 
2660 	if (!(req->flags & REQ_F_ISREG) && S_ISREG(file_inode(file)->i_mode))
2661 		req->flags |= REQ_F_ISREG;
2662 
2663 	kiocb->ki_pos = READ_ONCE(sqe->off);
2664 	if (kiocb->ki_pos == -1 && !(file->f_mode & FMODE_STREAM)) {
2665 		req->flags |= REQ_F_CUR_POS;
2666 		kiocb->ki_pos = file->f_pos;
2667 	}
2668 	kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
2669 	kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
2670 	ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
2671 	if (unlikely(ret))
2672 		return ret;
2673 
2674 	/* don't allow async punt for O_NONBLOCK or RWF_NOWAIT */
2675 	if ((kiocb->ki_flags & IOCB_NOWAIT) || (file->f_flags & O_NONBLOCK))
2676 		req->flags |= REQ_F_NOWAIT;
2677 
2678 	ioprio = READ_ONCE(sqe->ioprio);
2679 	if (ioprio) {
2680 		ret = ioprio_check_cap(ioprio);
2681 		if (ret)
2682 			return ret;
2683 
2684 		kiocb->ki_ioprio = ioprio;
2685 	} else
2686 		kiocb->ki_ioprio = get_current_ioprio();
2687 
2688 	if (ctx->flags & IORING_SETUP_IOPOLL) {
2689 		if (!(kiocb->ki_flags & IOCB_DIRECT) ||
2690 		    !kiocb->ki_filp->f_op->iopoll)
2691 			return -EOPNOTSUPP;
2692 
2693 		kiocb->ki_flags |= IOCB_HIPRI;
2694 		kiocb->ki_complete = io_complete_rw_iopoll;
2695 		req->iopoll_completed = 0;
2696 	} else {
2697 		if (kiocb->ki_flags & IOCB_HIPRI)
2698 			return -EINVAL;
2699 		kiocb->ki_complete = io_complete_rw;
2700 	}
2701 
2702 	if (req->opcode == IORING_OP_READ_FIXED ||
2703 	    req->opcode == IORING_OP_WRITE_FIXED) {
2704 		req->imu = NULL;
2705 		io_req_set_rsrc_node(req);
2706 	}
2707 
2708 	req->rw.addr = READ_ONCE(sqe->addr);
2709 	req->rw.len = READ_ONCE(sqe->len);
2710 	req->buf_index = READ_ONCE(sqe->buf_index);
2711 	return 0;
2712 }
2713 
io_rw_done(struct kiocb * kiocb,ssize_t ret)2714 static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
2715 {
2716 	switch (ret) {
2717 	case -EIOCBQUEUED:
2718 		break;
2719 	case -ERESTARTSYS:
2720 	case -ERESTARTNOINTR:
2721 	case -ERESTARTNOHAND:
2722 	case -ERESTART_RESTARTBLOCK:
2723 		/*
2724 		 * We can't just restart the syscall, since previously
2725 		 * submitted sqes may already be in progress. Just fail this
2726 		 * IO with EINTR.
2727 		 */
2728 		ret = -EINTR;
2729 		fallthrough;
2730 	default:
2731 		kiocb->ki_complete(kiocb, ret, 0);
2732 	}
2733 }
2734 
kiocb_done(struct kiocb * kiocb,ssize_t ret,unsigned int issue_flags)2735 static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
2736 		       unsigned int issue_flags)
2737 {
2738 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2739 	struct io_async_rw *io = req->async_data;
2740 	bool check_reissue = kiocb->ki_complete == io_complete_rw;
2741 
2742 	/* add previously done IO, if any */
2743 	if (io && io->bytes_done > 0) {
2744 		if (ret < 0)
2745 			ret = io->bytes_done;
2746 		else
2747 			ret += io->bytes_done;
2748 	}
2749 
2750 	if (req->flags & REQ_F_CUR_POS)
2751 		req->file->f_pos = kiocb->ki_pos;
2752 	if (ret >= 0 && kiocb->ki_complete == io_complete_rw)
2753 		__io_complete_rw(req, ret, 0, issue_flags);
2754 	else
2755 		io_rw_done(kiocb, ret);
2756 
2757 	if (check_reissue && req->flags & REQ_F_REISSUE) {
2758 		req->flags &= ~REQ_F_REISSUE;
2759 		if (io_resubmit_prep(req)) {
2760 			req_ref_get(req);
2761 			io_queue_async_work(req);
2762 		} else {
2763 			int cflags = 0;
2764 
2765 			req_set_fail_links(req);
2766 			if (req->flags & REQ_F_BUFFER_SELECTED)
2767 				cflags = io_put_rw_kbuf(req);
2768 			__io_req_complete(req, issue_flags, ret, cflags);
2769 		}
2770 	}
2771 }
2772 
__io_import_fixed(struct io_kiocb * req,int rw,struct iov_iter * iter,struct io_mapped_ubuf * imu)2773 static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
2774 			     struct io_mapped_ubuf *imu)
2775 {
2776 	size_t len = req->rw.len;
2777 	u64 buf_end, buf_addr = req->rw.addr;
2778 	size_t offset;
2779 
2780 	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
2781 		return -EFAULT;
2782 	/* not inside the mapped region */
2783 	if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
2784 		return -EFAULT;
2785 
2786 	/*
2787 	 * May not be a start of buffer, set size appropriately
2788 	 * and advance us to the beginning.
2789 	 */
2790 	offset = buf_addr - imu->ubuf;
2791 	iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
2792 
2793 	if (offset) {
2794 		/*
2795 		 * Don't use iov_iter_advance() here, as it's really slow for
2796 		 * using the latter parts of a big fixed buffer - it iterates
2797 		 * over each segment manually. We can cheat a bit here, because
2798 		 * we know that:
2799 		 *
2800 		 * 1) it's a BVEC iter, we set it up
2801 		 * 2) all bvecs are PAGE_SIZE in size, except potentially the
2802 		 *    first and last bvec
2803 		 *
2804 		 * So just find our index, and adjust the iterator afterwards.
2805 		 * If the offset is within the first bvec (or the whole first
2806 		 * bvec, just use iov_iter_advance(). This makes it easier
2807 		 * since we can just skip the first segment, which may not
2808 		 * be PAGE_SIZE aligned.
2809 		 */
2810 		const struct bio_vec *bvec = imu->bvec;
2811 
2812 		if (offset <= bvec->bv_len) {
2813 			iov_iter_advance(iter, offset);
2814 		} else {
2815 			unsigned long seg_skip;
2816 
2817 			/* skip first vec */
2818 			offset -= bvec->bv_len;
2819 			seg_skip = 1 + (offset >> PAGE_SHIFT);
2820 
2821 			iter->bvec = bvec + seg_skip;
2822 			iter->nr_segs -= seg_skip;
2823 			iter->count -= bvec->bv_len + offset;
2824 			iter->iov_offset = offset & ~PAGE_MASK;
2825 		}
2826 	}
2827 
2828 	return 0;
2829 }
2830 
io_import_fixed(struct io_kiocb * req,int rw,struct iov_iter * iter)2831 static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter)
2832 {
2833 	struct io_ring_ctx *ctx = req->ctx;
2834 	struct io_mapped_ubuf *imu = req->imu;
2835 	u16 index, buf_index = req->buf_index;
2836 
2837 	if (likely(!imu)) {
2838 		if (unlikely(buf_index >= ctx->nr_user_bufs))
2839 			return -EFAULT;
2840 		index = array_index_nospec(buf_index, ctx->nr_user_bufs);
2841 		imu = READ_ONCE(ctx->user_bufs[index]);
2842 		req->imu = imu;
2843 	}
2844 	return __io_import_fixed(req, rw, iter, imu);
2845 }
2846 
io_ring_submit_unlock(struct io_ring_ctx * ctx,bool needs_lock)2847 static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock)
2848 {
2849 	if (needs_lock)
2850 		mutex_unlock(&ctx->uring_lock);
2851 }
2852 
io_ring_submit_lock(struct io_ring_ctx * ctx,bool needs_lock)2853 static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock)
2854 {
2855 	/*
2856 	 * "Normal" inline submissions always hold the uring_lock, since we
2857 	 * grab it from the system call. Same is true for the SQPOLL offload.
2858 	 * The only exception is when we've detached the request and issue it
2859 	 * from an async worker thread, grab the lock for that case.
2860 	 */
2861 	if (needs_lock)
2862 		mutex_lock(&ctx->uring_lock);
2863 }
2864 
io_buffer_select(struct io_kiocb * req,size_t * len,int bgid,struct io_buffer * kbuf,bool needs_lock)2865 static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
2866 					  int bgid, struct io_buffer *kbuf,
2867 					  bool needs_lock)
2868 {
2869 	struct io_buffer *head;
2870 
2871 	if (req->flags & REQ_F_BUFFER_SELECTED)
2872 		return kbuf;
2873 
2874 	io_ring_submit_lock(req->ctx, needs_lock);
2875 
2876 	lockdep_assert_held(&req->ctx->uring_lock);
2877 
2878 	head = xa_load(&req->ctx->io_buffers, bgid);
2879 	if (head) {
2880 		if (!list_empty(&head->list)) {
2881 			kbuf = list_last_entry(&head->list, struct io_buffer,
2882 							list);
2883 			list_del(&kbuf->list);
2884 		} else {
2885 			kbuf = head;
2886 			xa_erase(&req->ctx->io_buffers, bgid);
2887 		}
2888 		if (*len > kbuf->len)
2889 			*len = kbuf->len;
2890 	} else {
2891 		kbuf = ERR_PTR(-ENOBUFS);
2892 	}
2893 
2894 	io_ring_submit_unlock(req->ctx, needs_lock);
2895 
2896 	return kbuf;
2897 }
2898 
io_rw_buffer_select(struct io_kiocb * req,size_t * len,bool needs_lock)2899 static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
2900 					bool needs_lock)
2901 {
2902 	struct io_buffer *kbuf;
2903 	u16 bgid;
2904 
2905 	kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
2906 	bgid = req->buf_index;
2907 	kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock);
2908 	if (IS_ERR(kbuf))
2909 		return kbuf;
2910 	req->rw.addr = (u64) (unsigned long) kbuf;
2911 	req->flags |= REQ_F_BUFFER_SELECTED;
2912 	return u64_to_user_ptr(kbuf->addr);
2913 }
2914 
2915 #ifdef CONFIG_COMPAT
io_compat_import(struct io_kiocb * req,struct iovec * iov,bool needs_lock)2916 static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
2917 				bool needs_lock)
2918 {
2919 	struct compat_iovec __user *uiov;
2920 	compat_ssize_t clen;
2921 	void __user *buf;
2922 	ssize_t len;
2923 
2924 	uiov = u64_to_user_ptr(req->rw.addr);
2925 	if (!access_ok(uiov, sizeof(*uiov)))
2926 		return -EFAULT;
2927 	if (__get_user(clen, &uiov->iov_len))
2928 		return -EFAULT;
2929 	if (clen < 0)
2930 		return -EINVAL;
2931 
2932 	len = clen;
2933 	buf = io_rw_buffer_select(req, &len, needs_lock);
2934 	if (IS_ERR(buf))
2935 		return PTR_ERR(buf);
2936 	iov[0].iov_base = buf;
2937 	iov[0].iov_len = (compat_size_t) len;
2938 	return 0;
2939 }
2940 #endif
2941 
__io_iov_buffer_select(struct io_kiocb * req,struct iovec * iov,bool needs_lock)2942 static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
2943 				      bool needs_lock)
2944 {
2945 	struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
2946 	void __user *buf;
2947 	ssize_t len;
2948 
2949 	if (copy_from_user(iov, uiov, sizeof(*uiov)))
2950 		return -EFAULT;
2951 
2952 	len = iov[0].iov_len;
2953 	if (len < 0)
2954 		return -EINVAL;
2955 	buf = io_rw_buffer_select(req, &len, needs_lock);
2956 	if (IS_ERR(buf))
2957 		return PTR_ERR(buf);
2958 	iov[0].iov_base = buf;
2959 	iov[0].iov_len = len;
2960 	return 0;
2961 }
2962 
io_iov_buffer_select(struct io_kiocb * req,struct iovec * iov,bool needs_lock)2963 static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
2964 				    bool needs_lock)
2965 {
2966 	if (req->flags & REQ_F_BUFFER_SELECTED) {
2967 		struct io_buffer *kbuf;
2968 
2969 		kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
2970 		iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
2971 		iov[0].iov_len = kbuf->len;
2972 		return 0;
2973 	}
2974 	if (req->rw.len != 1)
2975 		return -EINVAL;
2976 
2977 #ifdef CONFIG_COMPAT
2978 	if (req->ctx->compat)
2979 		return io_compat_import(req, iov, needs_lock);
2980 #endif
2981 
2982 	return __io_iov_buffer_select(req, iov, needs_lock);
2983 }
2984 
io_import_iovec(int rw,struct io_kiocb * req,struct iovec ** iovec,struct iov_iter * iter,bool needs_lock)2985 static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec,
2986 			   struct iov_iter *iter, bool needs_lock)
2987 {
2988 	void __user *buf = u64_to_user_ptr(req->rw.addr);
2989 	size_t sqe_len = req->rw.len;
2990 	u8 opcode = req->opcode;
2991 	ssize_t ret;
2992 
2993 	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
2994 		*iovec = NULL;
2995 		return io_import_fixed(req, rw, iter);
2996 	}
2997 
2998 	/* buffer index only valid with fixed read/write, or buffer select  */
2999 	if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT))
3000 		return -EINVAL;
3001 
3002 	if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
3003 		if (req->flags & REQ_F_BUFFER_SELECT) {
3004 			buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
3005 			if (IS_ERR(buf))
3006 				return PTR_ERR(buf);
3007 			req->rw.len = sqe_len;
3008 		}
3009 
3010 		ret = import_single_range(rw, buf, sqe_len, *iovec, iter);
3011 		*iovec = NULL;
3012 		return ret;
3013 	}
3014 
3015 	if (req->flags & REQ_F_BUFFER_SELECT) {
3016 		ret = io_iov_buffer_select(req, *iovec, needs_lock);
3017 		if (!ret)
3018 			iov_iter_init(iter, rw, *iovec, 1, (*iovec)->iov_len);
3019 		*iovec = NULL;
3020 		return ret;
3021 	}
3022 
3023 	return __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter,
3024 			      req->ctx->compat);
3025 }
3026 
io_kiocb_ppos(struct kiocb * kiocb)3027 static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
3028 {
3029 	return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
3030 }
3031 
3032 /*
3033  * For files that don't have ->read_iter() and ->write_iter(), handle them
3034  * by looping over ->read() or ->write() manually.
3035  */
loop_rw_iter(int rw,struct io_kiocb * req,struct iov_iter * iter)3036 static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
3037 {
3038 	struct kiocb *kiocb = &req->rw.kiocb;
3039 	struct file *file = req->file;
3040 	ssize_t ret = 0;
3041 
3042 	/*
3043 	 * Don't support polled IO through this interface, and we can't
3044 	 * support non-blocking either. For the latter, this just causes
3045 	 * the kiocb to be handled from an async context.
3046 	 */
3047 	if (kiocb->ki_flags & IOCB_HIPRI)
3048 		return -EOPNOTSUPP;
3049 	if (kiocb->ki_flags & IOCB_NOWAIT)
3050 		return -EAGAIN;
3051 
3052 	while (iov_iter_count(iter)) {
3053 		struct iovec iovec;
3054 		ssize_t nr;
3055 
3056 		if (!iov_iter_is_bvec(iter)) {
3057 			iovec = iov_iter_iovec(iter);
3058 		} else {
3059 			iovec.iov_base = u64_to_user_ptr(req->rw.addr);
3060 			iovec.iov_len = req->rw.len;
3061 		}
3062 
3063 		if (rw == READ) {
3064 			nr = file->f_op->read(file, iovec.iov_base,
3065 					      iovec.iov_len, io_kiocb_ppos(kiocb));
3066 		} else {
3067 			nr = file->f_op->write(file, iovec.iov_base,
3068 					       iovec.iov_len, io_kiocb_ppos(kiocb));
3069 		}
3070 
3071 		if (nr < 0) {
3072 			if (!ret)
3073 				ret = nr;
3074 			break;
3075 		}
3076 		ret += nr;
3077 		if (nr != iovec.iov_len)
3078 			break;
3079 		req->rw.len -= nr;
3080 		req->rw.addr += nr;
3081 		iov_iter_advance(iter, nr);
3082 	}
3083 
3084 	return ret;
3085 }
3086 
io_req_map_rw(struct io_kiocb * req,const struct iovec * iovec,const struct iovec * fast_iov,struct iov_iter * iter)3087 static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
3088 			  const struct iovec *fast_iov, struct iov_iter *iter)
3089 {
3090 	struct io_async_rw *rw = req->async_data;
3091 
3092 	memcpy(&rw->iter, iter, sizeof(*iter));
3093 	rw->free_iovec = iovec;
3094 	rw->bytes_done = 0;
3095 	/* can only be fixed buffers, no need to do anything */
3096 	if (iov_iter_is_bvec(iter))
3097 		return;
3098 	if (!iovec) {
3099 		unsigned iov_off = 0;
3100 
3101 		rw->iter.iov = rw->fast_iov;
3102 		if (iter->iov != fast_iov) {
3103 			iov_off = iter->iov - fast_iov;
3104 			rw->iter.iov += iov_off;
3105 		}
3106 		if (rw->fast_iov != fast_iov)
3107 			memcpy(rw->fast_iov + iov_off, fast_iov + iov_off,
3108 			       sizeof(struct iovec) * iter->nr_segs);
3109 	} else {
3110 		req->flags |= REQ_F_NEED_CLEANUP;
3111 	}
3112 }
3113 
io_alloc_async_data(struct io_kiocb * req)3114 static inline int io_alloc_async_data(struct io_kiocb *req)
3115 {
3116 	WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
3117 	req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
3118 	return req->async_data == NULL;
3119 }
3120 
io_setup_async_rw(struct io_kiocb * req,const struct iovec * iovec,const struct iovec * fast_iov,struct iov_iter * iter,bool force)3121 static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
3122 			     const struct iovec *fast_iov,
3123 			     struct iov_iter *iter, bool force)
3124 {
3125 	if (!force && !io_op_defs[req->opcode].needs_async_setup)
3126 		return 0;
3127 	if (!req->async_data) {
3128 		if (io_alloc_async_data(req)) {
3129 			kfree(iovec);
3130 			return -ENOMEM;
3131 		}
3132 
3133 		io_req_map_rw(req, iovec, fast_iov, iter);
3134 	}
3135 	return 0;
3136 }
3137 
io_rw_prep_async(struct io_kiocb * req,int rw)3138 static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
3139 {
3140 	struct io_async_rw *iorw = req->async_data;
3141 	struct iovec *iov = iorw->fast_iov;
3142 	int ret;
3143 
3144 	ret = io_import_iovec(rw, req, &iov, &iorw->iter, false);
3145 	if (unlikely(ret < 0))
3146 		return ret;
3147 
3148 	iorw->bytes_done = 0;
3149 	iorw->free_iovec = iov;
3150 	if (iov)
3151 		req->flags |= REQ_F_NEED_CLEANUP;
3152 	return 0;
3153 }
3154 
io_read_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3155 static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3156 {
3157 	if (unlikely(!(req->file->f_mode & FMODE_READ)))
3158 		return -EBADF;
3159 	return io_prep_rw(req, sqe);
3160 }
3161 
3162 /*
3163  * This is our waitqueue callback handler, registered through lock_page_async()
3164  * when we initially tried to do the IO with the iocb armed our waitqueue.
3165  * This gets called when the page is unlocked, and we generally expect that to
3166  * happen when the page IO is completed and the page is now uptodate. This will
3167  * queue a task_work based retry of the operation, attempting to copy the data
3168  * again. If the latter fails because the page was NOT uptodate, then we will
3169  * do a thread based blocking retry of the operation. That's the unexpected
3170  * slow path.
3171  */
io_async_buf_func(struct wait_queue_entry * wait,unsigned mode,int sync,void * arg)3172 static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
3173 			     int sync, void *arg)
3174 {
3175 	struct wait_page_queue *wpq;
3176 	struct io_kiocb *req = wait->private;
3177 	struct wait_page_key *key = arg;
3178 
3179 	wpq = container_of(wait, struct wait_page_queue, wait);
3180 
3181 	if (!wake_page_match(wpq, key))
3182 		return 0;
3183 
3184 	req->rw.kiocb.ki_flags &= ~IOCB_WAITQ;
3185 	list_del_init(&wait->entry);
3186 
3187 	/* submit ref gets dropped, acquire a new one */
3188 	req_ref_get(req);
3189 	io_req_task_queue(req);
3190 	return 1;
3191 }
3192 
3193 /*
3194  * This controls whether a given IO request should be armed for async page
3195  * based retry. If we return false here, the request is handed to the async
3196  * worker threads for retry. If we're doing buffered reads on a regular file,
3197  * we prepare a private wait_page_queue entry and retry the operation. This
3198  * will either succeed because the page is now uptodate and unlocked, or it
3199  * will register a callback when the page is unlocked at IO completion. Through
3200  * that callback, io_uring uses task_work to setup a retry of the operation.
3201  * That retry will attempt the buffered read again. The retry will generally
3202  * succeed, or in rare cases where it fails, we then fall back to using the
3203  * async worker threads for a blocking retry.
3204  */
io_rw_should_retry(struct io_kiocb * req)3205 static bool io_rw_should_retry(struct io_kiocb *req)
3206 {
3207 	struct io_async_rw *rw = req->async_data;
3208 	struct wait_page_queue *wait = &rw->wpq;
3209 	struct kiocb *kiocb = &req->rw.kiocb;
3210 
3211 	/* never retry for NOWAIT, we just complete with -EAGAIN */
3212 	if (req->flags & REQ_F_NOWAIT)
3213 		return false;
3214 
3215 	/* Only for buffered IO */
3216 	if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
3217 		return false;
3218 
3219 	/*
3220 	 * just use poll if we can, and don't attempt if the fs doesn't
3221 	 * support callback based unlocks
3222 	 */
3223 	if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
3224 		return false;
3225 
3226 	wait->wait.func = io_async_buf_func;
3227 	wait->wait.private = req;
3228 	wait->wait.flags = 0;
3229 	INIT_LIST_HEAD(&wait->wait.entry);
3230 	kiocb->ki_flags |= IOCB_WAITQ;
3231 	kiocb->ki_flags &= ~IOCB_NOWAIT;
3232 	kiocb->ki_waitq = wait;
3233 	return true;
3234 }
3235 
io_iter_do_read(struct io_kiocb * req,struct iov_iter * iter)3236 static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
3237 {
3238 	if (req->file->f_op->read_iter)
3239 		return call_read_iter(req->file, &req->rw.kiocb, iter);
3240 	else if (req->file->f_op->read)
3241 		return loop_rw_iter(READ, req, iter);
3242 	else
3243 		return -EINVAL;
3244 }
3245 
io_read(struct io_kiocb * req,unsigned int issue_flags)3246 static int io_read(struct io_kiocb *req, unsigned int issue_flags)
3247 {
3248 	struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
3249 	struct kiocb *kiocb = &req->rw.kiocb;
3250 	struct iov_iter __iter, *iter = &__iter;
3251 	struct io_async_rw *rw = req->async_data;
3252 	ssize_t io_size, ret, ret2;
3253 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
3254 
3255 	if (rw) {
3256 		iter = &rw->iter;
3257 		iovec = NULL;
3258 	} else {
3259 		ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock);
3260 		if (ret < 0)
3261 			return ret;
3262 	}
3263 	io_size = iov_iter_count(iter);
3264 	req->result = io_size;
3265 
3266 	/* Ensure we clear previously set non-block flag */
3267 	if (!force_nonblock)
3268 		kiocb->ki_flags &= ~IOCB_NOWAIT;
3269 	else
3270 		kiocb->ki_flags |= IOCB_NOWAIT;
3271 
3272 	/* If the file doesn't support async, just async punt */
3273 	if (force_nonblock && !io_file_supports_async(req, READ)) {
3274 		ret = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
3275 		return ret ?: -EAGAIN;
3276 	}
3277 
3278 	ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), io_size);
3279 	if (unlikely(ret)) {
3280 		kfree(iovec);
3281 		return ret;
3282 	}
3283 
3284 	ret = io_iter_do_read(req, iter);
3285 
3286 	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
3287 		req->flags &= ~REQ_F_REISSUE;
3288 		/* IOPOLL retry should happen for io-wq threads */
3289 		if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
3290 			goto done;
3291 		/* no retry on NONBLOCK nor RWF_NOWAIT */
3292 		if (req->flags & REQ_F_NOWAIT)
3293 			goto done;
3294 		/* some cases will consume bytes even on error returns */
3295 		iov_iter_revert(iter, io_size - iov_iter_count(iter));
3296 		ret = 0;
3297 	} else if (ret == -EIOCBQUEUED) {
3298 		goto out_free;
3299 	} else if (ret <= 0 || ret == io_size || !force_nonblock ||
3300 		   (req->flags & REQ_F_NOWAIT) || !(req->flags & REQ_F_ISREG)) {
3301 		/* read all, failed, already did sync or don't want to retry */
3302 		goto done;
3303 	}
3304 
3305 	ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
3306 	if (ret2)
3307 		return ret2;
3308 
3309 	iovec = NULL;
3310 	rw = req->async_data;
3311 	/* now use our persistent iterator, if we aren't already */
3312 	iter = &rw->iter;
3313 
3314 	do {
3315 		io_size -= ret;
3316 		rw->bytes_done += ret;
3317 		/* if we can retry, do so with the callbacks armed */
3318 		if (!io_rw_should_retry(req)) {
3319 			kiocb->ki_flags &= ~IOCB_WAITQ;
3320 			return -EAGAIN;
3321 		}
3322 
3323 		/*
3324 		 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
3325 		 * we get -EIOCBQUEUED, then we'll get a notification when the
3326 		 * desired page gets unlocked. We can also get a partial read
3327 		 * here, and if we do, then just retry at the new offset.
3328 		 */
3329 		ret = io_iter_do_read(req, iter);
3330 		if (ret == -EIOCBQUEUED)
3331 			return 0;
3332 		/* we got some bytes, but not all. retry. */
3333 		kiocb->ki_flags &= ~IOCB_WAITQ;
3334 	} while (ret > 0 && ret < io_size);
3335 done:
3336 	kiocb_done(kiocb, ret, issue_flags);
3337 out_free:
3338 	/* it's faster to check here then delegate to kfree */
3339 	if (iovec)
3340 		kfree(iovec);
3341 	return 0;
3342 }
3343 
io_write_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3344 static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3345 {
3346 	if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
3347 		return -EBADF;
3348 	return io_prep_rw(req, sqe);
3349 }
3350 
io_write(struct io_kiocb * req,unsigned int issue_flags)3351 static int io_write(struct io_kiocb *req, unsigned int issue_flags)
3352 {
3353 	struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
3354 	struct kiocb *kiocb = &req->rw.kiocb;
3355 	struct iov_iter __iter, *iter = &__iter;
3356 	struct io_async_rw *rw = req->async_data;
3357 	ssize_t ret, ret2, io_size;
3358 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
3359 
3360 	if (rw) {
3361 		iter = &rw->iter;
3362 		iovec = NULL;
3363 	} else {
3364 		ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock);
3365 		if (ret < 0)
3366 			return ret;
3367 	}
3368 	io_size = iov_iter_count(iter);
3369 	req->result = io_size;
3370 
3371 	/* Ensure we clear previously set non-block flag */
3372 	if (!force_nonblock)
3373 		kiocb->ki_flags &= ~IOCB_NOWAIT;
3374 	else
3375 		kiocb->ki_flags |= IOCB_NOWAIT;
3376 
3377 	/* If the file doesn't support async, just async punt */
3378 	if (force_nonblock && !io_file_supports_async(req, WRITE))
3379 		goto copy_iov;
3380 
3381 	/* file path doesn't support NOWAIT for non-direct_IO */
3382 	if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
3383 	    (req->flags & REQ_F_ISREG))
3384 		goto copy_iov;
3385 
3386 	ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), io_size);
3387 	if (unlikely(ret))
3388 		goto out_free;
3389 
3390 	/*
3391 	 * Open-code file_start_write here to grab freeze protection,
3392 	 * which will be released by another thread in
3393 	 * io_complete_rw().  Fool lockdep by telling it the lock got
3394 	 * released so that it doesn't complain about the held lock when
3395 	 * we return to userspace.
3396 	 */
3397 	if (req->flags & REQ_F_ISREG) {
3398 		sb_start_write(file_inode(req->file)->i_sb);
3399 		__sb_writers_release(file_inode(req->file)->i_sb,
3400 					SB_FREEZE_WRITE);
3401 	}
3402 	kiocb->ki_flags |= IOCB_WRITE;
3403 
3404 	if (req->file->f_op->write_iter)
3405 		ret2 = call_write_iter(req->file, kiocb, iter);
3406 	else if (req->file->f_op->write)
3407 		ret2 = loop_rw_iter(WRITE, req, iter);
3408 	else
3409 		ret2 = -EINVAL;
3410 
3411 	if (req->flags & REQ_F_REISSUE) {
3412 		req->flags &= ~REQ_F_REISSUE;
3413 		ret2 = -EAGAIN;
3414 	}
3415 
3416 	/*
3417 	 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
3418 	 * retry them without IOCB_NOWAIT.
3419 	 */
3420 	if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
3421 		ret2 = -EAGAIN;
3422 	/* no retry on NONBLOCK nor RWF_NOWAIT */
3423 	if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
3424 		goto done;
3425 	if (!force_nonblock || ret2 != -EAGAIN) {
3426 		/* IOPOLL retry should happen for io-wq threads */
3427 		if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
3428 			goto copy_iov;
3429 done:
3430 		kiocb_done(kiocb, ret2, issue_flags);
3431 	} else {
3432 copy_iov:
3433 		/* some cases will consume bytes even on error returns */
3434 		iov_iter_revert(iter, io_size - iov_iter_count(iter));
3435 		ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
3436 		return ret ?: -EAGAIN;
3437 	}
3438 out_free:
3439 	/* it's reportedly faster than delegating the null check to kfree() */
3440 	if (iovec)
3441 		kfree(iovec);
3442 	return ret;
3443 }
3444 
io_renameat_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3445 static int io_renameat_prep(struct io_kiocb *req,
3446 			    const struct io_uring_sqe *sqe)
3447 {
3448 	struct io_rename *ren = &req->rename;
3449 	const char __user *oldf, *newf;
3450 
3451 	if (unlikely(req->flags & REQ_F_FIXED_FILE))
3452 		return -EBADF;
3453 
3454 	ren->old_dfd = READ_ONCE(sqe->fd);
3455 	oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
3456 	newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
3457 	ren->new_dfd = READ_ONCE(sqe->len);
3458 	ren->flags = READ_ONCE(sqe->rename_flags);
3459 
3460 	ren->oldpath = getname(oldf);
3461 	if (IS_ERR(ren->oldpath))
3462 		return PTR_ERR(ren->oldpath);
3463 
3464 	ren->newpath = getname(newf);
3465 	if (IS_ERR(ren->newpath)) {
3466 		putname(ren->oldpath);
3467 		return PTR_ERR(ren->newpath);
3468 	}
3469 
3470 	req->flags |= REQ_F_NEED_CLEANUP;
3471 	return 0;
3472 }
3473 
io_renameat(struct io_kiocb * req,unsigned int issue_flags)3474 static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
3475 {
3476 	struct io_rename *ren = &req->rename;
3477 	int ret;
3478 
3479 	if (issue_flags & IO_URING_F_NONBLOCK)
3480 		return -EAGAIN;
3481 
3482 	ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd,
3483 				ren->newpath, ren->flags);
3484 
3485 	req->flags &= ~REQ_F_NEED_CLEANUP;
3486 	if (ret < 0)
3487 		req_set_fail_links(req);
3488 	io_req_complete(req, ret);
3489 	return 0;
3490 }
3491 
io_unlinkat_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3492 static int io_unlinkat_prep(struct io_kiocb *req,
3493 			    const struct io_uring_sqe *sqe)
3494 {
3495 	struct io_unlink *un = &req->unlink;
3496 	const char __user *fname;
3497 
3498 	if (unlikely(req->flags & REQ_F_FIXED_FILE))
3499 		return -EBADF;
3500 
3501 	un->dfd = READ_ONCE(sqe->fd);
3502 
3503 	un->flags = READ_ONCE(sqe->unlink_flags);
3504 	if (un->flags & ~AT_REMOVEDIR)
3505 		return -EINVAL;
3506 
3507 	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
3508 	un->filename = getname(fname);
3509 	if (IS_ERR(un->filename))
3510 		return PTR_ERR(un->filename);
3511 
3512 	req->flags |= REQ_F_NEED_CLEANUP;
3513 	return 0;
3514 }
3515 
io_unlinkat(struct io_kiocb * req,unsigned int issue_flags)3516 static int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
3517 {
3518 	struct io_unlink *un = &req->unlink;
3519 	int ret;
3520 
3521 	if (issue_flags & IO_URING_F_NONBLOCK)
3522 		return -EAGAIN;
3523 
3524 	if (un->flags & AT_REMOVEDIR)
3525 		ret = do_rmdir(un->dfd, un->filename);
3526 	else
3527 		ret = do_unlinkat(un->dfd, un->filename);
3528 
3529 	req->flags &= ~REQ_F_NEED_CLEANUP;
3530 	if (ret < 0)
3531 		req_set_fail_links(req);
3532 	io_req_complete(req, ret);
3533 	return 0;
3534 }
3535 
io_shutdown_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3536 static int io_shutdown_prep(struct io_kiocb *req,
3537 			    const struct io_uring_sqe *sqe)
3538 {
3539 #if defined(CONFIG_NET)
3540 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3541 		return -EINVAL;
3542 	if (sqe->ioprio || sqe->off || sqe->addr || sqe->rw_flags ||
3543 	    sqe->buf_index)
3544 		return -EINVAL;
3545 
3546 	req->shutdown.how = READ_ONCE(sqe->len);
3547 	return 0;
3548 #else
3549 	return -EOPNOTSUPP;
3550 #endif
3551 }
3552 
io_shutdown(struct io_kiocb * req,unsigned int issue_flags)3553 static int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
3554 {
3555 #if defined(CONFIG_NET)
3556 	struct socket *sock;
3557 	int ret;
3558 
3559 	if (issue_flags & IO_URING_F_NONBLOCK)
3560 		return -EAGAIN;
3561 
3562 	sock = sock_from_file(req->file);
3563 	if (unlikely(!sock))
3564 		return -ENOTSOCK;
3565 
3566 	ret = __sys_shutdown_sock(sock, req->shutdown.how);
3567 	if (ret < 0)
3568 		req_set_fail_links(req);
3569 	io_req_complete(req, ret);
3570 	return 0;
3571 #else
3572 	return -EOPNOTSUPP;
3573 #endif
3574 }
3575 
__io_splice_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3576 static int __io_splice_prep(struct io_kiocb *req,
3577 			    const struct io_uring_sqe *sqe)
3578 {
3579 	struct io_splice* sp = &req->splice;
3580 	unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
3581 
3582 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3583 		return -EINVAL;
3584 
3585 	sp->file_in = NULL;
3586 	sp->len = READ_ONCE(sqe->len);
3587 	sp->flags = READ_ONCE(sqe->splice_flags);
3588 
3589 	if (unlikely(sp->flags & ~valid_flags))
3590 		return -EINVAL;
3591 
3592 	sp->file_in = io_file_get(NULL, req, READ_ONCE(sqe->splice_fd_in),
3593 				  (sp->flags & SPLICE_F_FD_IN_FIXED));
3594 	if (!sp->file_in)
3595 		return -EBADF;
3596 	req->flags |= REQ_F_NEED_CLEANUP;
3597 	return 0;
3598 }
3599 
io_tee_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3600 static int io_tee_prep(struct io_kiocb *req,
3601 		       const struct io_uring_sqe *sqe)
3602 {
3603 	if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
3604 		return -EINVAL;
3605 	return __io_splice_prep(req, sqe);
3606 }
3607 
io_tee(struct io_kiocb * req,unsigned int issue_flags)3608 static int io_tee(struct io_kiocb *req, unsigned int issue_flags)
3609 {
3610 	struct io_splice *sp = &req->splice;
3611 	struct file *in = sp->file_in;
3612 	struct file *out = sp->file_out;
3613 	unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
3614 	long ret = 0;
3615 
3616 	if (issue_flags & IO_URING_F_NONBLOCK)
3617 		return -EAGAIN;
3618 	if (sp->len)
3619 		ret = do_tee(in, out, sp->len, flags);
3620 
3621 	if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
3622 		io_put_file(in);
3623 	req->flags &= ~REQ_F_NEED_CLEANUP;
3624 
3625 	if (ret != sp->len)
3626 		req_set_fail_links(req);
3627 	io_req_complete(req, ret);
3628 	return 0;
3629 }
3630 
io_splice_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3631 static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3632 {
3633 	struct io_splice* sp = &req->splice;
3634 
3635 	sp->off_in = READ_ONCE(sqe->splice_off_in);
3636 	sp->off_out = READ_ONCE(sqe->off);
3637 	return __io_splice_prep(req, sqe);
3638 }
3639 
io_splice(struct io_kiocb * req,unsigned int issue_flags)3640 static int io_splice(struct io_kiocb *req, unsigned int issue_flags)
3641 {
3642 	struct io_splice *sp = &req->splice;
3643 	struct file *in = sp->file_in;
3644 	struct file *out = sp->file_out;
3645 	unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
3646 	loff_t *poff_in, *poff_out;
3647 	long ret = 0;
3648 
3649 	if (issue_flags & IO_URING_F_NONBLOCK)
3650 		return -EAGAIN;
3651 
3652 	poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
3653 	poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
3654 
3655 	if (sp->len)
3656 		ret = do_splice(in, poff_in, out, poff_out, sp->len, flags);
3657 
3658 	if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
3659 		io_put_file(in);
3660 	req->flags &= ~REQ_F_NEED_CLEANUP;
3661 
3662 	if (ret != sp->len)
3663 		req_set_fail_links(req);
3664 	io_req_complete(req, ret);
3665 	return 0;
3666 }
3667 
3668 /*
3669  * IORING_OP_NOP just posts a completion event, nothing else.
3670  */
io_nop(struct io_kiocb * req,unsigned int issue_flags)3671 static int io_nop(struct io_kiocb *req, unsigned int issue_flags)
3672 {
3673 	struct io_ring_ctx *ctx = req->ctx;
3674 
3675 	if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
3676 		return -EINVAL;
3677 
3678 	__io_req_complete(req, issue_flags, 0, 0);
3679 	return 0;
3680 }
3681 
io_fsync_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3682 static int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3683 {
3684 	struct io_ring_ctx *ctx = req->ctx;
3685 
3686 	if (!req->file)
3687 		return -EBADF;
3688 
3689 	if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
3690 		return -EINVAL;
3691 	if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
3692 		return -EINVAL;
3693 
3694 	req->sync.flags = READ_ONCE(sqe->fsync_flags);
3695 	if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC))
3696 		return -EINVAL;
3697 
3698 	req->sync.off = READ_ONCE(sqe->off);
3699 	req->sync.len = READ_ONCE(sqe->len);
3700 	return 0;
3701 }
3702 
io_fsync(struct io_kiocb * req,unsigned int issue_flags)3703 static int io_fsync(struct io_kiocb *req, unsigned int issue_flags)
3704 {
3705 	loff_t end = req->sync.off + req->sync.len;
3706 	int ret;
3707 
3708 	/* fsync always requires a blocking context */
3709 	if (issue_flags & IO_URING_F_NONBLOCK)
3710 		return -EAGAIN;
3711 
3712 	ret = vfs_fsync_range(req->file, req->sync.off,
3713 				end > 0 ? end : LLONG_MAX,
3714 				req->sync.flags & IORING_FSYNC_DATASYNC);
3715 	if (ret < 0)
3716 		req_set_fail_links(req);
3717 	io_req_complete(req, ret);
3718 	return 0;
3719 }
3720 
io_fallocate_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3721 static int io_fallocate_prep(struct io_kiocb *req,
3722 			     const struct io_uring_sqe *sqe)
3723 {
3724 	if (sqe->ioprio || sqe->buf_index || sqe->rw_flags)
3725 		return -EINVAL;
3726 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3727 		return -EINVAL;
3728 
3729 	req->sync.off = READ_ONCE(sqe->off);
3730 	req->sync.len = READ_ONCE(sqe->addr);
3731 	req->sync.mode = READ_ONCE(sqe->len);
3732 	return 0;
3733 }
3734 
io_fallocate(struct io_kiocb * req,unsigned int issue_flags)3735 static int io_fallocate(struct io_kiocb *req, unsigned int issue_flags)
3736 {
3737 	int ret;
3738 
3739 	/* fallocate always requiring blocking context */
3740 	if (issue_flags & IO_URING_F_NONBLOCK)
3741 		return -EAGAIN;
3742 	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
3743 				req->sync.len);
3744 	if (ret < 0)
3745 		req_set_fail_links(req);
3746 	io_req_complete(req, ret);
3747 	return 0;
3748 }
3749 
__io_openat_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3750 static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3751 {
3752 	const char __user *fname;
3753 	int ret;
3754 
3755 	if (unlikely(sqe->ioprio || sqe->buf_index))
3756 		return -EINVAL;
3757 	if (unlikely(req->flags & REQ_F_FIXED_FILE))
3758 		return -EBADF;
3759 
3760 	/* open.how should be already initialised */
3761 	if (!(req->open.how.flags & O_PATH) && force_o_largefile())
3762 		req->open.how.flags |= O_LARGEFILE;
3763 
3764 	req->open.dfd = READ_ONCE(sqe->fd);
3765 	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
3766 	req->open.filename = getname(fname);
3767 	if (IS_ERR(req->open.filename)) {
3768 		ret = PTR_ERR(req->open.filename);
3769 		req->open.filename = NULL;
3770 		return ret;
3771 	}
3772 	req->open.nofile = rlimit(RLIMIT_NOFILE);
3773 	req->flags |= REQ_F_NEED_CLEANUP;
3774 	return 0;
3775 }
3776 
io_openat_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3777 static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3778 {
3779 	u64 flags, mode;
3780 
3781 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3782 		return -EINVAL;
3783 	mode = READ_ONCE(sqe->len);
3784 	flags = READ_ONCE(sqe->open_flags);
3785 	req->open.how = build_open_how(flags, mode);
3786 	return __io_openat_prep(req, sqe);
3787 }
3788 
io_openat2_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3789 static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3790 {
3791 	struct open_how __user *how;
3792 	size_t len;
3793 	int ret;
3794 
3795 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3796 		return -EINVAL;
3797 	how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
3798 	len = READ_ONCE(sqe->len);
3799 	if (len < OPEN_HOW_SIZE_VER0)
3800 		return -EINVAL;
3801 
3802 	ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how,
3803 					len);
3804 	if (ret)
3805 		return ret;
3806 
3807 	return __io_openat_prep(req, sqe);
3808 }
3809 
io_openat2(struct io_kiocb * req,unsigned int issue_flags)3810 static int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
3811 {
3812 	struct open_flags op;
3813 	struct file *file;
3814 	bool nonblock_set;
3815 	bool resolve_nonblock;
3816 	int ret;
3817 
3818 	ret = build_open_flags(&req->open.how, &op);
3819 	if (ret)
3820 		goto err;
3821 	nonblock_set = op.open_flag & O_NONBLOCK;
3822 	resolve_nonblock = req->open.how.resolve & RESOLVE_CACHED;
3823 	if (issue_flags & IO_URING_F_NONBLOCK) {
3824 		/*
3825 		 * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
3826 		 * it'll always -EAGAIN
3827 		 */
3828 		if (req->open.how.flags & (O_TRUNC | O_CREAT | O_TMPFILE))
3829 			return -EAGAIN;
3830 		op.lookup_flags |= LOOKUP_CACHED;
3831 		op.open_flag |= O_NONBLOCK;
3832 	}
3833 
3834 	ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);
3835 	if (ret < 0)
3836 		goto err;
3837 
3838 	file = do_filp_open(req->open.dfd, req->open.filename, &op);
3839 	/* only retry if RESOLVE_CACHED wasn't already set by application */
3840 	if ((!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)) &&
3841 	    file == ERR_PTR(-EAGAIN)) {
3842 		/*
3843 		 * We could hang on to this 'fd', but seems like marginal
3844 		 * gain for something that is now known to be a slower path.
3845 		 * So just put it, and we'll get a new one when we retry.
3846 		 */
3847 		put_unused_fd(ret);
3848 		return -EAGAIN;
3849 	}
3850 
3851 	if (IS_ERR(file)) {
3852 		put_unused_fd(ret);
3853 		ret = PTR_ERR(file);
3854 	} else {
3855 		if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
3856 			file->f_flags &= ~O_NONBLOCK;
3857 		fsnotify_open(file);
3858 		fd_install(ret, file);
3859 	}
3860 err:
3861 	putname(req->open.filename);
3862 	req->flags &= ~REQ_F_NEED_CLEANUP;
3863 	if (ret < 0)
3864 		req_set_fail_links(req);
3865 	__io_req_complete(req, issue_flags, ret, 0);
3866 	return 0;
3867 }
3868 
io_openat(struct io_kiocb * req,unsigned int issue_flags)3869 static int io_openat(struct io_kiocb *req, unsigned int issue_flags)
3870 {
3871 	return io_openat2(req, issue_flags);
3872 }
3873 
io_remove_buffers_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3874 static int io_remove_buffers_prep(struct io_kiocb *req,
3875 				  const struct io_uring_sqe *sqe)
3876 {
3877 	struct io_provide_buf *p = &req->pbuf;
3878 	u64 tmp;
3879 
3880 	if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off)
3881 		return -EINVAL;
3882 
3883 	tmp = READ_ONCE(sqe->fd);
3884 	if (!tmp || tmp > USHRT_MAX)
3885 		return -EINVAL;
3886 
3887 	memset(p, 0, sizeof(*p));
3888 	p->nbufs = tmp;
3889 	p->bgid = READ_ONCE(sqe->buf_group);
3890 	return 0;
3891 }
3892 
__io_remove_buffers(struct io_ring_ctx * ctx,struct io_buffer * buf,int bgid,unsigned nbufs)3893 static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf,
3894 			       int bgid, unsigned nbufs)
3895 {
3896 	unsigned i = 0;
3897 
3898 	/* shouldn't happen */
3899 	if (!nbufs)
3900 		return 0;
3901 
3902 	/* the head kbuf is the list itself */
3903 	while (!list_empty(&buf->list)) {
3904 		struct io_buffer *nxt;
3905 
3906 		nxt = list_first_entry(&buf->list, struct io_buffer, list);
3907 		list_del(&nxt->list);
3908 		kfree(nxt);
3909 		if (++i == nbufs)
3910 			return i;
3911 	}
3912 	i++;
3913 	kfree(buf);
3914 	xa_erase(&ctx->io_buffers, bgid);
3915 
3916 	return i;
3917 }
3918 
io_remove_buffers(struct io_kiocb * req,unsigned int issue_flags)3919 static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
3920 {
3921 	struct io_provide_buf *p = &req->pbuf;
3922 	struct io_ring_ctx *ctx = req->ctx;
3923 	struct io_buffer *head;
3924 	int ret = 0;
3925 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
3926 
3927 	io_ring_submit_lock(ctx, !force_nonblock);
3928 
3929 	lockdep_assert_held(&ctx->uring_lock);
3930 
3931 	ret = -ENOENT;
3932 	head = xa_load(&ctx->io_buffers, p->bgid);
3933 	if (head)
3934 		ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs);
3935 	if (ret < 0)
3936 		req_set_fail_links(req);
3937 
3938 	/* complete before unlock, IOPOLL may need the lock */
3939 	__io_req_complete(req, issue_flags, ret, 0);
3940 	io_ring_submit_unlock(ctx, !force_nonblock);
3941 	return 0;
3942 }
3943 
io_provide_buffers_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)3944 static int io_provide_buffers_prep(struct io_kiocb *req,
3945 				   const struct io_uring_sqe *sqe)
3946 {
3947 	unsigned long size, tmp_check;
3948 	struct io_provide_buf *p = &req->pbuf;
3949 	u64 tmp;
3950 
3951 	if (sqe->ioprio || sqe->rw_flags)
3952 		return -EINVAL;
3953 
3954 	tmp = READ_ONCE(sqe->fd);
3955 	if (!tmp || tmp > USHRT_MAX)
3956 		return -E2BIG;
3957 	p->nbufs = tmp;
3958 	p->addr = READ_ONCE(sqe->addr);
3959 	p->len = READ_ONCE(sqe->len);
3960 
3961 	if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs,
3962 				&size))
3963 		return -EOVERFLOW;
3964 	if (check_add_overflow((unsigned long)p->addr, size, &tmp_check))
3965 		return -EOVERFLOW;
3966 
3967 	size = (unsigned long)p->len * p->nbufs;
3968 	if (!access_ok(u64_to_user_ptr(p->addr), size))
3969 		return -EFAULT;
3970 
3971 	p->bgid = READ_ONCE(sqe->buf_group);
3972 	tmp = READ_ONCE(sqe->off);
3973 	if (tmp > USHRT_MAX)
3974 		return -E2BIG;
3975 	p->bid = tmp;
3976 	return 0;
3977 }
3978 
io_add_buffers(struct io_provide_buf * pbuf,struct io_buffer ** head)3979 static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head)
3980 {
3981 	struct io_buffer *buf;
3982 	u64 addr = pbuf->addr;
3983 	int i, bid = pbuf->bid;
3984 
3985 	for (i = 0; i < pbuf->nbufs; i++) {
3986 		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
3987 		if (!buf)
3988 			break;
3989 
3990 		buf->addr = addr;
3991 		buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT);
3992 		buf->bid = bid;
3993 		addr += pbuf->len;
3994 		bid++;
3995 		if (!*head) {
3996 			INIT_LIST_HEAD(&buf->list);
3997 			*head = buf;
3998 		} else {
3999 			list_add_tail(&buf->list, &(*head)->list);
4000 		}
4001 	}
4002 
4003 	return i ? i : -ENOMEM;
4004 }
4005 
io_provide_buffers(struct io_kiocb * req,unsigned int issue_flags)4006 static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
4007 {
4008 	struct io_provide_buf *p = &req->pbuf;
4009 	struct io_ring_ctx *ctx = req->ctx;
4010 	struct io_buffer *head, *list;
4011 	int ret = 0;
4012 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4013 
4014 	io_ring_submit_lock(ctx, !force_nonblock);
4015 
4016 	lockdep_assert_held(&ctx->uring_lock);
4017 
4018 	list = head = xa_load(&ctx->io_buffers, p->bgid);
4019 
4020 	ret = io_add_buffers(p, &head);
4021 	if (ret >= 0 && !list) {
4022 		ret = xa_insert(&ctx->io_buffers, p->bgid, head, GFP_KERNEL);
4023 		if (ret < 0)
4024 			__io_remove_buffers(ctx, head, p->bgid, -1U);
4025 	}
4026 	if (ret < 0)
4027 		req_set_fail_links(req);
4028 	/* complete before unlock, IOPOLL may need the lock */
4029 	__io_req_complete(req, issue_flags, ret, 0);
4030 	io_ring_submit_unlock(ctx, !force_nonblock);
4031 	return 0;
4032 }
4033 
io_epoll_ctl_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4034 static int io_epoll_ctl_prep(struct io_kiocb *req,
4035 			     const struct io_uring_sqe *sqe)
4036 {
4037 #if defined(CONFIG_EPOLL)
4038 	if (sqe->ioprio || sqe->buf_index)
4039 		return -EINVAL;
4040 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4041 		return -EINVAL;
4042 
4043 	req->epoll.epfd = READ_ONCE(sqe->fd);
4044 	req->epoll.op = READ_ONCE(sqe->len);
4045 	req->epoll.fd = READ_ONCE(sqe->off);
4046 
4047 	if (ep_op_has_event(req->epoll.op)) {
4048 		struct epoll_event __user *ev;
4049 
4050 		ev = u64_to_user_ptr(READ_ONCE(sqe->addr));
4051 		if (copy_from_user(&req->epoll.event, ev, sizeof(*ev)))
4052 			return -EFAULT;
4053 	}
4054 
4055 	return 0;
4056 #else
4057 	return -EOPNOTSUPP;
4058 #endif
4059 }
4060 
io_epoll_ctl(struct io_kiocb * req,unsigned int issue_flags)4061 static int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags)
4062 {
4063 #if defined(CONFIG_EPOLL)
4064 	struct io_epoll *ie = &req->epoll;
4065 	int ret;
4066 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4067 
4068 	ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock);
4069 	if (force_nonblock && ret == -EAGAIN)
4070 		return -EAGAIN;
4071 
4072 	if (ret < 0)
4073 		req_set_fail_links(req);
4074 	__io_req_complete(req, issue_flags, ret, 0);
4075 	return 0;
4076 #else
4077 	return -EOPNOTSUPP;
4078 #endif
4079 }
4080 
io_madvise_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4081 static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4082 {
4083 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
4084 	if (sqe->ioprio || sqe->buf_index || sqe->off)
4085 		return -EINVAL;
4086 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4087 		return -EINVAL;
4088 
4089 	req->madvise.addr = READ_ONCE(sqe->addr);
4090 	req->madvise.len = READ_ONCE(sqe->len);
4091 	req->madvise.advice = READ_ONCE(sqe->fadvise_advice);
4092 	return 0;
4093 #else
4094 	return -EOPNOTSUPP;
4095 #endif
4096 }
4097 
io_madvise(struct io_kiocb * req,unsigned int issue_flags)4098 static int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
4099 {
4100 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
4101 	struct io_madvise *ma = &req->madvise;
4102 	int ret;
4103 
4104 	if (issue_flags & IO_URING_F_NONBLOCK)
4105 		return -EAGAIN;
4106 
4107 	ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
4108 	if (ret < 0)
4109 		req_set_fail_links(req);
4110 	io_req_complete(req, ret);
4111 	return 0;
4112 #else
4113 	return -EOPNOTSUPP;
4114 #endif
4115 }
4116 
io_fadvise_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4117 static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4118 {
4119 	if (sqe->ioprio || sqe->buf_index || sqe->addr)
4120 		return -EINVAL;
4121 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4122 		return -EINVAL;
4123 
4124 	req->fadvise.offset = READ_ONCE(sqe->off);
4125 	req->fadvise.len = READ_ONCE(sqe->len);
4126 	req->fadvise.advice = READ_ONCE(sqe->fadvise_advice);
4127 	return 0;
4128 }
4129 
io_fadvise(struct io_kiocb * req,unsigned int issue_flags)4130 static int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
4131 {
4132 	struct io_fadvise *fa = &req->fadvise;
4133 	int ret;
4134 
4135 	if (issue_flags & IO_URING_F_NONBLOCK) {
4136 		switch (fa->advice) {
4137 		case POSIX_FADV_NORMAL:
4138 		case POSIX_FADV_RANDOM:
4139 		case POSIX_FADV_SEQUENTIAL:
4140 			break;
4141 		default:
4142 			return -EAGAIN;
4143 		}
4144 	}
4145 
4146 	ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
4147 	if (ret < 0)
4148 		req_set_fail_links(req);
4149 	__io_req_complete(req, issue_flags, ret, 0);
4150 	return 0;
4151 }
4152 
io_statx_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4153 static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4154 {
4155 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4156 		return -EINVAL;
4157 	if (sqe->ioprio || sqe->buf_index)
4158 		return -EINVAL;
4159 	if (req->flags & REQ_F_FIXED_FILE)
4160 		return -EBADF;
4161 
4162 	req->statx.dfd = READ_ONCE(sqe->fd);
4163 	req->statx.mask = READ_ONCE(sqe->len);
4164 	req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr));
4165 	req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
4166 	req->statx.flags = READ_ONCE(sqe->statx_flags);
4167 
4168 	return 0;
4169 }
4170 
io_statx(struct io_kiocb * req,unsigned int issue_flags)4171 static int io_statx(struct io_kiocb *req, unsigned int issue_flags)
4172 {
4173 	struct io_statx *ctx = &req->statx;
4174 	int ret;
4175 
4176 	if (issue_flags & IO_URING_F_NONBLOCK)
4177 		return -EAGAIN;
4178 
4179 	ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask,
4180 		       ctx->buffer);
4181 
4182 	if (ret < 0)
4183 		req_set_fail_links(req);
4184 	io_req_complete(req, ret);
4185 	return 0;
4186 }
4187 
io_close_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4188 static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4189 {
4190 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4191 		return -EINVAL;
4192 	if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
4193 	    sqe->rw_flags || sqe->buf_index)
4194 		return -EINVAL;
4195 	if (req->flags & REQ_F_FIXED_FILE)
4196 		return -EBADF;
4197 
4198 	req->close.fd = READ_ONCE(sqe->fd);
4199 	return 0;
4200 }
4201 
io_close(struct io_kiocb * req,unsigned int issue_flags)4202 static int io_close(struct io_kiocb *req, unsigned int issue_flags)
4203 {
4204 	struct files_struct *files = current->files;
4205 	struct io_close *close = &req->close;
4206 	struct fdtable *fdt;
4207 	struct file *file = NULL;
4208 	int ret = -EBADF;
4209 
4210 	spin_lock(&files->file_lock);
4211 	fdt = files_fdtable(files);
4212 	if (close->fd >= fdt->max_fds) {
4213 		spin_unlock(&files->file_lock);
4214 		goto err;
4215 	}
4216 	file = fdt->fd[close->fd];
4217 	if (!file || file->f_op == &io_uring_fops) {
4218 		spin_unlock(&files->file_lock);
4219 		file = NULL;
4220 		goto err;
4221 	}
4222 
4223 	/* if the file has a flush method, be safe and punt to async */
4224 	if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
4225 		spin_unlock(&files->file_lock);
4226 		return -EAGAIN;
4227 	}
4228 
4229 	ret = __close_fd_get_file(close->fd, &file);
4230 	spin_unlock(&files->file_lock);
4231 	if (ret < 0) {
4232 		if (ret == -ENOENT)
4233 			ret = -EBADF;
4234 		goto err;
4235 	}
4236 
4237 	/* No ->flush() or already async, safely close from here */
4238 	ret = filp_close(file, current->files);
4239 err:
4240 	if (ret < 0)
4241 		req_set_fail_links(req);
4242 	if (file)
4243 		fput(file);
4244 	__io_req_complete(req, issue_flags, ret, 0);
4245 	return 0;
4246 }
4247 
io_sfr_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4248 static int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4249 {
4250 	struct io_ring_ctx *ctx = req->ctx;
4251 
4252 	if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
4253 		return -EINVAL;
4254 	if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
4255 		return -EINVAL;
4256 
4257 	req->sync.off = READ_ONCE(sqe->off);
4258 	req->sync.len = READ_ONCE(sqe->len);
4259 	req->sync.flags = READ_ONCE(sqe->sync_range_flags);
4260 	return 0;
4261 }
4262 
io_sync_file_range(struct io_kiocb * req,unsigned int issue_flags)4263 static int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
4264 {
4265 	int ret;
4266 
4267 	/* sync_file_range always requires a blocking context */
4268 	if (issue_flags & IO_URING_F_NONBLOCK)
4269 		return -EAGAIN;
4270 
4271 	ret = sync_file_range(req->file, req->sync.off, req->sync.len,
4272 				req->sync.flags);
4273 	if (ret < 0)
4274 		req_set_fail_links(req);
4275 	io_req_complete(req, ret);
4276 	return 0;
4277 }
4278 
4279 #if defined(CONFIG_NET)
io_setup_async_msg(struct io_kiocb * req,struct io_async_msghdr * kmsg)4280 static int io_setup_async_msg(struct io_kiocb *req,
4281 			      struct io_async_msghdr *kmsg)
4282 {
4283 	struct io_async_msghdr *async_msg = req->async_data;
4284 
4285 	if (async_msg)
4286 		return -EAGAIN;
4287 	if (io_alloc_async_data(req)) {
4288 		kfree(kmsg->free_iov);
4289 		return -ENOMEM;
4290 	}
4291 	async_msg = req->async_data;
4292 	req->flags |= REQ_F_NEED_CLEANUP;
4293 	memcpy(async_msg, kmsg, sizeof(*kmsg));
4294 	async_msg->msg.msg_name = &async_msg->addr;
4295 	/* if were using fast_iov, set it to the new one */
4296 	if (!async_msg->free_iov)
4297 		async_msg->msg.msg_iter.iov = async_msg->fast_iov;
4298 
4299 	return -EAGAIN;
4300 }
4301 
io_sendmsg_copy_hdr(struct io_kiocb * req,struct io_async_msghdr * iomsg)4302 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
4303 			       struct io_async_msghdr *iomsg)
4304 {
4305 	iomsg->msg.msg_name = &iomsg->addr;
4306 	iomsg->free_iov = iomsg->fast_iov;
4307 	return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
4308 				   req->sr_msg.msg_flags, &iomsg->free_iov);
4309 }
4310 
io_sendmsg_prep_async(struct io_kiocb * req)4311 static int io_sendmsg_prep_async(struct io_kiocb *req)
4312 {
4313 	int ret;
4314 
4315 	ret = io_sendmsg_copy_hdr(req, req->async_data);
4316 	if (!ret)
4317 		req->flags |= REQ_F_NEED_CLEANUP;
4318 	return ret;
4319 }
4320 
io_sendmsg_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4321 static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4322 {
4323 	struct io_sr_msg *sr = &req->sr_msg;
4324 
4325 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4326 		return -EINVAL;
4327 
4328 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
4329 	sr->len = READ_ONCE(sqe->len);
4330 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
4331 	if (sr->msg_flags & MSG_DONTWAIT)
4332 		req->flags |= REQ_F_NOWAIT;
4333 
4334 #ifdef CONFIG_COMPAT
4335 	if (req->ctx->compat)
4336 		sr->msg_flags |= MSG_CMSG_COMPAT;
4337 #endif
4338 	return 0;
4339 }
4340 
io_sendmsg(struct io_kiocb * req,unsigned int issue_flags)4341 static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
4342 {
4343 	struct io_async_msghdr iomsg, *kmsg;
4344 	struct socket *sock;
4345 	unsigned flags;
4346 	int min_ret = 0;
4347 	int ret;
4348 
4349 	sock = sock_from_file(req->file);
4350 	if (unlikely(!sock))
4351 		return -ENOTSOCK;
4352 
4353 	kmsg = req->async_data;
4354 	if (!kmsg) {
4355 		ret = io_sendmsg_copy_hdr(req, &iomsg);
4356 		if (ret)
4357 			return ret;
4358 		kmsg = &iomsg;
4359 	}
4360 
4361 	flags = req->sr_msg.msg_flags;
4362 	if (issue_flags & IO_URING_F_NONBLOCK)
4363 		flags |= MSG_DONTWAIT;
4364 	if (flags & MSG_WAITALL)
4365 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
4366 
4367 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
4368 	if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN)
4369 		return io_setup_async_msg(req, kmsg);
4370 	if (ret == -ERESTARTSYS)
4371 		ret = -EINTR;
4372 
4373 	/* fast path, check for non-NULL to avoid function call */
4374 	if (kmsg->free_iov)
4375 		kfree(kmsg->free_iov);
4376 	req->flags &= ~REQ_F_NEED_CLEANUP;
4377 	if (ret < min_ret)
4378 		req_set_fail_links(req);
4379 	__io_req_complete(req, issue_flags, ret, 0);
4380 	return 0;
4381 }
4382 
io_send(struct io_kiocb * req,unsigned int issue_flags)4383 static int io_send(struct io_kiocb *req, unsigned int issue_flags)
4384 {
4385 	struct io_sr_msg *sr = &req->sr_msg;
4386 	struct msghdr msg;
4387 	struct iovec iov;
4388 	struct socket *sock;
4389 	unsigned flags;
4390 	int min_ret = 0;
4391 	int ret;
4392 
4393 	sock = sock_from_file(req->file);
4394 	if (unlikely(!sock))
4395 		return -ENOTSOCK;
4396 
4397 	ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
4398 	if (unlikely(ret))
4399 		return ret;
4400 
4401 	msg.msg_name = NULL;
4402 	msg.msg_control = NULL;
4403 	msg.msg_controllen = 0;
4404 	msg.msg_namelen = 0;
4405 
4406 	flags = req->sr_msg.msg_flags;
4407 	if (issue_flags & IO_URING_F_NONBLOCK)
4408 		flags |= MSG_DONTWAIT;
4409 	if (flags & MSG_WAITALL)
4410 		min_ret = iov_iter_count(&msg.msg_iter);
4411 
4412 	msg.msg_flags = flags;
4413 	ret = sock_sendmsg(sock, &msg);
4414 	if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN)
4415 		return -EAGAIN;
4416 	if (ret == -ERESTARTSYS)
4417 		ret = -EINTR;
4418 
4419 	if (ret < min_ret)
4420 		req_set_fail_links(req);
4421 	__io_req_complete(req, issue_flags, ret, 0);
4422 	return 0;
4423 }
4424 
__io_recvmsg_copy_hdr(struct io_kiocb * req,struct io_async_msghdr * iomsg)4425 static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
4426 				 struct io_async_msghdr *iomsg)
4427 {
4428 	struct io_sr_msg *sr = &req->sr_msg;
4429 	struct iovec __user *uiov;
4430 	size_t iov_len;
4431 	int ret;
4432 
4433 	ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
4434 					&iomsg->uaddr, &uiov, &iov_len);
4435 	if (ret)
4436 		return ret;
4437 
4438 	if (req->flags & REQ_F_BUFFER_SELECT) {
4439 		if (iov_len > 1)
4440 			return -EINVAL;
4441 		if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov)))
4442 			return -EFAULT;
4443 		sr->len = iomsg->fast_iov[0].iov_len;
4444 		iomsg->free_iov = NULL;
4445 	} else {
4446 		iomsg->free_iov = iomsg->fast_iov;
4447 		ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
4448 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
4449 				     false);
4450 		if (ret > 0)
4451 			ret = 0;
4452 	}
4453 
4454 	return ret;
4455 }
4456 
4457 #ifdef CONFIG_COMPAT
__io_compat_recvmsg_copy_hdr(struct io_kiocb * req,struct io_async_msghdr * iomsg)4458 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
4459 					struct io_async_msghdr *iomsg)
4460 {
4461 	struct io_sr_msg *sr = &req->sr_msg;
4462 	struct compat_iovec __user *uiov;
4463 	compat_uptr_t ptr;
4464 	compat_size_t len;
4465 	int ret;
4466 
4467 	ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr,
4468 				  &ptr, &len);
4469 	if (ret)
4470 		return ret;
4471 
4472 	uiov = compat_ptr(ptr);
4473 	if (req->flags & REQ_F_BUFFER_SELECT) {
4474 		compat_ssize_t clen;
4475 
4476 		if (len > 1)
4477 			return -EINVAL;
4478 		if (!access_ok(uiov, sizeof(*uiov)))
4479 			return -EFAULT;
4480 		if (__get_user(clen, &uiov->iov_len))
4481 			return -EFAULT;
4482 		if (clen < 0)
4483 			return -EINVAL;
4484 		sr->len = clen;
4485 		iomsg->free_iov = NULL;
4486 	} else {
4487 		iomsg->free_iov = iomsg->fast_iov;
4488 		ret = __import_iovec(READ, (struct iovec __user *)uiov, len,
4489 				   UIO_FASTIOV, &iomsg->free_iov,
4490 				   &iomsg->msg.msg_iter, true);
4491 		if (ret < 0)
4492 			return ret;
4493 	}
4494 
4495 	return 0;
4496 }
4497 #endif
4498 
io_recvmsg_copy_hdr(struct io_kiocb * req,struct io_async_msghdr * iomsg)4499 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
4500 			       struct io_async_msghdr *iomsg)
4501 {
4502 	iomsg->msg.msg_name = &iomsg->addr;
4503 
4504 #ifdef CONFIG_COMPAT
4505 	if (req->ctx->compat)
4506 		return __io_compat_recvmsg_copy_hdr(req, iomsg);
4507 #endif
4508 
4509 	return __io_recvmsg_copy_hdr(req, iomsg);
4510 }
4511 
io_recv_buffer_select(struct io_kiocb * req,bool needs_lock)4512 static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
4513 					       bool needs_lock)
4514 {
4515 	struct io_sr_msg *sr = &req->sr_msg;
4516 	struct io_buffer *kbuf;
4517 
4518 	kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock);
4519 	if (IS_ERR(kbuf))
4520 		return kbuf;
4521 
4522 	sr->kbuf = kbuf;
4523 	req->flags |= REQ_F_BUFFER_SELECTED;
4524 	return kbuf;
4525 }
4526 
io_put_recv_kbuf(struct io_kiocb * req)4527 static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req)
4528 {
4529 	return io_put_kbuf(req, req->sr_msg.kbuf);
4530 }
4531 
io_recvmsg_prep_async(struct io_kiocb * req)4532 static int io_recvmsg_prep_async(struct io_kiocb *req)
4533 {
4534 	int ret;
4535 
4536 	ret = io_recvmsg_copy_hdr(req, req->async_data);
4537 	if (!ret)
4538 		req->flags |= REQ_F_NEED_CLEANUP;
4539 	return ret;
4540 }
4541 
io_recvmsg_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4542 static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4543 {
4544 	struct io_sr_msg *sr = &req->sr_msg;
4545 
4546 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4547 		return -EINVAL;
4548 
4549 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
4550 	sr->len = READ_ONCE(sqe->len);
4551 	sr->bgid = READ_ONCE(sqe->buf_group);
4552 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
4553 	if (sr->msg_flags & MSG_DONTWAIT)
4554 		req->flags |= REQ_F_NOWAIT;
4555 
4556 #ifdef CONFIG_COMPAT
4557 	if (req->ctx->compat)
4558 		sr->msg_flags |= MSG_CMSG_COMPAT;
4559 #endif
4560 	return 0;
4561 }
4562 
io_recvmsg(struct io_kiocb * req,unsigned int issue_flags)4563 static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
4564 {
4565 	struct io_async_msghdr iomsg, *kmsg;
4566 	struct socket *sock;
4567 	struct io_buffer *kbuf;
4568 	unsigned flags;
4569 	int min_ret = 0;
4570 	int ret, cflags = 0;
4571 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4572 
4573 	sock = sock_from_file(req->file);
4574 	if (unlikely(!sock))
4575 		return -ENOTSOCK;
4576 
4577 	kmsg = req->async_data;
4578 	if (!kmsg) {
4579 		ret = io_recvmsg_copy_hdr(req, &iomsg);
4580 		if (ret)
4581 			return ret;
4582 		kmsg = &iomsg;
4583 	}
4584 
4585 	if (req->flags & REQ_F_BUFFER_SELECT) {
4586 		kbuf = io_recv_buffer_select(req, !force_nonblock);
4587 		if (IS_ERR(kbuf))
4588 			return PTR_ERR(kbuf);
4589 		kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
4590 		kmsg->fast_iov[0].iov_len = req->sr_msg.len;
4591 		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov,
4592 				1, req->sr_msg.len);
4593 	}
4594 
4595 	flags = req->sr_msg.msg_flags;
4596 	if (force_nonblock)
4597 		flags |= MSG_DONTWAIT;
4598 	if (flags & MSG_WAITALL)
4599 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
4600 
4601 	ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
4602 					kmsg->uaddr, flags);
4603 	if (force_nonblock && ret == -EAGAIN)
4604 		return io_setup_async_msg(req, kmsg);
4605 	if (ret == -ERESTARTSYS)
4606 		ret = -EINTR;
4607 
4608 	if (req->flags & REQ_F_BUFFER_SELECTED)
4609 		cflags = io_put_recv_kbuf(req);
4610 	/* fast path, check for non-NULL to avoid function call */
4611 	if (kmsg->free_iov)
4612 		kfree(kmsg->free_iov);
4613 	req->flags &= ~REQ_F_NEED_CLEANUP;
4614 	if (ret < min_ret || ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
4615 		req_set_fail_links(req);
4616 	__io_req_complete(req, issue_flags, ret, cflags);
4617 	return 0;
4618 }
4619 
io_recv(struct io_kiocb * req,unsigned int issue_flags)4620 static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
4621 {
4622 	struct io_buffer *kbuf;
4623 	struct io_sr_msg *sr = &req->sr_msg;
4624 	struct msghdr msg;
4625 	void __user *buf = sr->buf;
4626 	struct socket *sock;
4627 	struct iovec iov;
4628 	unsigned flags;
4629 	int min_ret = 0;
4630 	int ret, cflags = 0;
4631 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4632 
4633 	sock = sock_from_file(req->file);
4634 	if (unlikely(!sock))
4635 		return -ENOTSOCK;
4636 
4637 	if (req->flags & REQ_F_BUFFER_SELECT) {
4638 		kbuf = io_recv_buffer_select(req, !force_nonblock);
4639 		if (IS_ERR(kbuf))
4640 			return PTR_ERR(kbuf);
4641 		buf = u64_to_user_ptr(kbuf->addr);
4642 	}
4643 
4644 	ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter);
4645 	if (unlikely(ret))
4646 		goto out_free;
4647 
4648 	msg.msg_name = NULL;
4649 	msg.msg_control = NULL;
4650 	msg.msg_controllen = 0;
4651 	msg.msg_namelen = 0;
4652 	msg.msg_iocb = NULL;
4653 	msg.msg_flags = 0;
4654 
4655 	flags = req->sr_msg.msg_flags;
4656 	if (force_nonblock)
4657 		flags |= MSG_DONTWAIT;
4658 	if (flags & MSG_WAITALL)
4659 		min_ret = iov_iter_count(&msg.msg_iter);
4660 
4661 	ret = sock_recvmsg(sock, &msg, flags);
4662 	if (force_nonblock && ret == -EAGAIN)
4663 		return -EAGAIN;
4664 	if (ret == -ERESTARTSYS)
4665 		ret = -EINTR;
4666 out_free:
4667 	if (req->flags & REQ_F_BUFFER_SELECTED)
4668 		cflags = io_put_recv_kbuf(req);
4669 	if (ret < min_ret || ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
4670 		req_set_fail_links(req);
4671 	__io_req_complete(req, issue_flags, ret, cflags);
4672 	return 0;
4673 }
4674 
io_accept_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4675 static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4676 {
4677 	struct io_accept *accept = &req->accept;
4678 
4679 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4680 		return -EINVAL;
4681 	if (sqe->ioprio || sqe->len || sqe->buf_index)
4682 		return -EINVAL;
4683 
4684 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
4685 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
4686 	accept->flags = READ_ONCE(sqe->accept_flags);
4687 	accept->nofile = rlimit(RLIMIT_NOFILE);
4688 	return 0;
4689 }
4690 
io_accept(struct io_kiocb * req,unsigned int issue_flags)4691 static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
4692 {
4693 	struct io_accept *accept = &req->accept;
4694 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4695 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
4696 	int ret;
4697 
4698 	if (req->file->f_flags & O_NONBLOCK)
4699 		req->flags |= REQ_F_NOWAIT;
4700 
4701 	ret = __sys_accept4_file(req->file, file_flags, accept->addr,
4702 					accept->addr_len, accept->flags,
4703 					accept->nofile);
4704 	if (ret == -EAGAIN && force_nonblock)
4705 		return -EAGAIN;
4706 	if (ret < 0) {
4707 		if (ret == -ERESTARTSYS)
4708 			ret = -EINTR;
4709 		req_set_fail_links(req);
4710 	}
4711 	__io_req_complete(req, issue_flags, ret, 0);
4712 	return 0;
4713 }
4714 
io_connect_prep_async(struct io_kiocb * req)4715 static int io_connect_prep_async(struct io_kiocb *req)
4716 {
4717 	struct io_async_connect *io = req->async_data;
4718 	struct io_connect *conn = &req->connect;
4719 
4720 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
4721 }
4722 
io_connect_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)4723 static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4724 {
4725 	struct io_connect *conn = &req->connect;
4726 
4727 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4728 		return -EINVAL;
4729 	if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
4730 		return -EINVAL;
4731 
4732 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
4733 	conn->addr_len =  READ_ONCE(sqe->addr2);
4734 	return 0;
4735 }
4736 
io_connect(struct io_kiocb * req,unsigned int issue_flags)4737 static int io_connect(struct io_kiocb *req, unsigned int issue_flags)
4738 {
4739 	struct io_async_connect __io, *io;
4740 	unsigned file_flags;
4741 	int ret;
4742 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
4743 
4744 	if (req->async_data) {
4745 		io = req->async_data;
4746 	} else {
4747 		ret = move_addr_to_kernel(req->connect.addr,
4748 						req->connect.addr_len,
4749 						&__io.address);
4750 		if (ret)
4751 			goto out;
4752 		io = &__io;
4753 	}
4754 
4755 	file_flags = force_nonblock ? O_NONBLOCK : 0;
4756 
4757 	ret = __sys_connect_file(req->file, &io->address,
4758 					req->connect.addr_len, file_flags);
4759 	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
4760 		if (req->async_data)
4761 			return -EAGAIN;
4762 		if (io_alloc_async_data(req)) {
4763 			ret = -ENOMEM;
4764 			goto out;
4765 		}
4766 		memcpy(req->async_data, &__io, sizeof(__io));
4767 		return -EAGAIN;
4768 	}
4769 	if (ret == -ERESTARTSYS)
4770 		ret = -EINTR;
4771 out:
4772 	if (ret < 0)
4773 		req_set_fail_links(req);
4774 	__io_req_complete(req, issue_flags, ret, 0);
4775 	return 0;
4776 }
4777 #else /* !CONFIG_NET */
4778 #define IO_NETOP_FN(op)							\
4779 static int io_##op(struct io_kiocb *req, unsigned int issue_flags)	\
4780 {									\
4781 	return -EOPNOTSUPP;						\
4782 }
4783 
4784 #define IO_NETOP_PREP(op)						\
4785 IO_NETOP_FN(op)								\
4786 static int io_##op##_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) \
4787 {									\
4788 	return -EOPNOTSUPP;						\
4789 }									\
4790 
4791 #define IO_NETOP_PREP_ASYNC(op)						\
4792 IO_NETOP_PREP(op)							\
4793 static int io_##op##_prep_async(struct io_kiocb *req)			\
4794 {									\
4795 	return -EOPNOTSUPP;						\
4796 }
4797 
4798 IO_NETOP_PREP_ASYNC(sendmsg);
4799 IO_NETOP_PREP_ASYNC(recvmsg);
4800 IO_NETOP_PREP_ASYNC(connect);
4801 IO_NETOP_PREP(accept);
4802 IO_NETOP_FN(send);
4803 IO_NETOP_FN(recv);
4804 #endif /* CONFIG_NET */
4805 
4806 struct io_poll_table {
4807 	struct poll_table_struct pt;
4808 	struct io_kiocb *req;
4809 	int error;
4810 };
4811 
__io_async_wake(struct io_kiocb * req,struct io_poll_iocb * poll,__poll_t mask,task_work_func_t func)4812 static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
4813 			   __poll_t mask, task_work_func_t func)
4814 {
4815 	int ret;
4816 
4817 	/* for instances that support it check for an event match first: */
4818 	if (mask && !(mask & poll->events))
4819 		return 0;
4820 
4821 	trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask);
4822 
4823 	list_del_init(&poll->wait.entry);
4824 
4825 	req->result = mask;
4826 	req->task_work.func = func;
4827 
4828 	/*
4829 	 * If this fails, then the task is exiting. When a task exits, the
4830 	 * work gets canceled, so just cancel this request as well instead
4831 	 * of executing it. We can't safely execute it anyway, as we may not
4832 	 * have the needed state needed for it anyway.
4833 	 */
4834 	ret = io_req_task_work_add(req);
4835 	if (unlikely(ret)) {
4836 		WRITE_ONCE(poll->canceled, true);
4837 		io_req_task_work_add_fallback(req, func);
4838 	}
4839 	return 1;
4840 }
4841 
io_poll_rewait(struct io_kiocb * req,struct io_poll_iocb * poll)4842 static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll)
4843 	__acquires(&req->ctx->completion_lock)
4844 {
4845 	struct io_ring_ctx *ctx = req->ctx;
4846 
4847 	if (!req->result && !READ_ONCE(poll->canceled)) {
4848 		struct poll_table_struct pt = { ._key = poll->events };
4849 
4850 		req->result = vfs_poll(req->file, &pt) & poll->events;
4851 	}
4852 
4853 	spin_lock_irq(&ctx->completion_lock);
4854 	if (!req->result && !READ_ONCE(poll->canceled)) {
4855 		add_wait_queue(poll->head, &poll->wait);
4856 		return true;
4857 	}
4858 
4859 	return false;
4860 }
4861 
io_poll_get_double(struct io_kiocb * req)4862 static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req)
4863 {
4864 	/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
4865 	if (req->opcode == IORING_OP_POLL_ADD)
4866 		return req->async_data;
4867 	return req->apoll->double_poll;
4868 }
4869 
io_poll_get_single(struct io_kiocb * req)4870 static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req)
4871 {
4872 	if (req->opcode == IORING_OP_POLL_ADD)
4873 		return &req->poll;
4874 	return &req->apoll->poll;
4875 }
4876 
io_poll_remove_double(struct io_kiocb * req)4877 static void io_poll_remove_double(struct io_kiocb *req)
4878 	__must_hold(&req->ctx->completion_lock)
4879 {
4880 	struct io_poll_iocb *poll = io_poll_get_double(req);
4881 
4882 	lockdep_assert_held(&req->ctx->completion_lock);
4883 
4884 	if (poll && poll->head) {
4885 		struct wait_queue_head *head = poll->head;
4886 
4887 		spin_lock(&head->lock);
4888 		list_del_init(&poll->wait.entry);
4889 		if (poll->wait.private)
4890 			req_ref_put(req);
4891 		poll->head = NULL;
4892 		spin_unlock(&head->lock);
4893 	}
4894 }
4895 
io_poll_complete(struct io_kiocb * req,__poll_t mask)4896 static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
4897 	__must_hold(&req->ctx->completion_lock)
4898 {
4899 	struct io_ring_ctx *ctx = req->ctx;
4900 	unsigned flags = IORING_CQE_F_MORE;
4901 	int error;
4902 
4903 	if (READ_ONCE(req->poll.canceled)) {
4904 		error = -ECANCELED;
4905 		req->poll.events |= EPOLLONESHOT;
4906 	} else {
4907 		error = mangle_poll(mask);
4908 	}
4909 	if (req->poll.events & EPOLLONESHOT)
4910 		flags = 0;
4911 	if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
4912 		io_poll_remove_waitqs(req);
4913 		req->poll.done = true;
4914 		flags = 0;
4915 	}
4916 	if (flags & IORING_CQE_F_MORE)
4917 		ctx->cq_extra++;
4918 
4919 	io_commit_cqring(ctx);
4920 	return !(flags & IORING_CQE_F_MORE);
4921 }
4922 
io_poll_task_func(struct callback_head * cb)4923 static void io_poll_task_func(struct callback_head *cb)
4924 {
4925 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
4926 	struct io_ring_ctx *ctx = req->ctx;
4927 	struct io_kiocb *nxt;
4928 
4929 	if (io_poll_rewait(req, &req->poll)) {
4930 		spin_unlock_irq(&ctx->completion_lock);
4931 	} else {
4932 		bool done;
4933 
4934 		done = io_poll_complete(req, req->result);
4935 		if (done) {
4936 			hash_del(&req->hash_node);
4937 		} else {
4938 			req->result = 0;
4939 			add_wait_queue(req->poll.head, &req->poll.wait);
4940 		}
4941 		spin_unlock_irq(&ctx->completion_lock);
4942 		io_cqring_ev_posted(ctx);
4943 
4944 		if (done) {
4945 			nxt = io_put_req_find_next(req);
4946 			if (nxt)
4947 				__io_req_task_submit(nxt);
4948 		}
4949 	}
4950 }
4951 
io_poll_double_wake(struct wait_queue_entry * wait,unsigned mode,int sync,void * key)4952 static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode,
4953 			       int sync, void *key)
4954 {
4955 	struct io_kiocb *req = wait->private;
4956 	struct io_poll_iocb *poll = io_poll_get_single(req);
4957 	__poll_t mask = key_to_poll(key);
4958 
4959 	/* for instances that support it check for an event match first: */
4960 	if (mask && !(mask & poll->events))
4961 		return 0;
4962 	if (!(poll->events & EPOLLONESHOT))
4963 		return poll->wait.func(&poll->wait, mode, sync, key);
4964 
4965 	list_del_init(&wait->entry);
4966 
4967 	if (poll && poll->head) {
4968 		bool done;
4969 
4970 		spin_lock(&poll->head->lock);
4971 		done = list_empty(&poll->wait.entry);
4972 		if (!done)
4973 			list_del_init(&poll->wait.entry);
4974 		/* make sure double remove sees this as being gone */
4975 		wait->private = NULL;
4976 		spin_unlock(&poll->head->lock);
4977 		if (!done) {
4978 			/* use wait func handler, so it matches the rq type */
4979 			poll->wait.func(&poll->wait, mode, sync, key);
4980 		}
4981 	}
4982 	req_ref_put(req);
4983 	return 1;
4984 }
4985 
io_init_poll_iocb(struct io_poll_iocb * poll,__poll_t events,wait_queue_func_t wake_func)4986 static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events,
4987 			      wait_queue_func_t wake_func)
4988 {
4989 	poll->head = NULL;
4990 	poll->done = false;
4991 	poll->canceled = false;
4992 #define IO_POLL_UNMASK	(EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
4993 	/* mask in events that we always want/need */
4994 	poll->events = events | IO_POLL_UNMASK;
4995 	INIT_LIST_HEAD(&poll->wait.entry);
4996 	init_waitqueue_func_entry(&poll->wait, wake_func);
4997 }
4998 
__io_queue_proc(struct io_poll_iocb * poll,struct io_poll_table * pt,struct wait_queue_head * head,struct io_poll_iocb ** poll_ptr)4999 static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
5000 			    struct wait_queue_head *head,
5001 			    struct io_poll_iocb **poll_ptr)
5002 {
5003 	struct io_kiocb *req = pt->req;
5004 
5005 	/*
5006 	 * If poll->head is already set, it's because the file being polled
5007 	 * uses multiple waitqueues for poll handling (eg one for read, one
5008 	 * for write). Setup a separate io_poll_iocb if this happens.
5009 	 */
5010 	if (unlikely(poll->head)) {
5011 		struct io_poll_iocb *poll_one = poll;
5012 
5013 		/* already have a 2nd entry, fail a third attempt */
5014 		if (*poll_ptr) {
5015 			pt->error = -EINVAL;
5016 			return;
5017 		}
5018 		/*
5019 		 * Can't handle multishot for double wait for now, turn it
5020 		 * into one-shot mode.
5021 		 */
5022 		if (!(req->poll.events & EPOLLONESHOT))
5023 			req->poll.events |= EPOLLONESHOT;
5024 		/* double add on the same waitqueue head, ignore */
5025 		if (poll->head == head)
5026 			return;
5027 		poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
5028 		if (!poll) {
5029 			pt->error = -ENOMEM;
5030 			return;
5031 		}
5032 		io_init_poll_iocb(poll, poll_one->events, io_poll_double_wake);
5033 		req_ref_get(req);
5034 		poll->wait.private = req;
5035 		*poll_ptr = poll;
5036 	}
5037 
5038 	pt->error = 0;
5039 	poll->head = head;
5040 
5041 	if (poll->events & EPOLLEXCLUSIVE)
5042 		add_wait_queue_exclusive(head, &poll->wait);
5043 	else
5044 		add_wait_queue(head, &poll->wait);
5045 }
5046 
io_async_queue_proc(struct file * file,struct wait_queue_head * head,struct poll_table_struct * p)5047 static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
5048 			       struct poll_table_struct *p)
5049 {
5050 	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
5051 	struct async_poll *apoll = pt->req->apoll;
5052 
5053 	__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
5054 }
5055 
io_async_task_func(struct callback_head * cb)5056 static void io_async_task_func(struct callback_head *cb)
5057 {
5058 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
5059 	struct async_poll *apoll = req->apoll;
5060 	struct io_ring_ctx *ctx = req->ctx;
5061 
5062 	trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
5063 
5064 	if (io_poll_rewait(req, &apoll->poll)) {
5065 		spin_unlock_irq(&ctx->completion_lock);
5066 		return;
5067 	}
5068 
5069 	hash_del(&req->hash_node);
5070 	io_poll_remove_double(req);
5071 	spin_unlock_irq(&ctx->completion_lock);
5072 
5073 	if (!READ_ONCE(apoll->poll.canceled))
5074 		__io_req_task_submit(req);
5075 	else
5076 		io_req_complete_failed(req, -ECANCELED);
5077 }
5078 
io_async_wake(struct wait_queue_entry * wait,unsigned mode,int sync,void * key)5079 static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
5080 			void *key)
5081 {
5082 	struct io_kiocb *req = wait->private;
5083 	struct io_poll_iocb *poll = &req->apoll->poll;
5084 
5085 	trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data,
5086 					key_to_poll(key));
5087 
5088 	return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func);
5089 }
5090 
io_poll_req_insert(struct io_kiocb * req)5091 static void io_poll_req_insert(struct io_kiocb *req)
5092 {
5093 	struct io_ring_ctx *ctx = req->ctx;
5094 	struct hlist_head *list;
5095 
5096 	list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
5097 	hlist_add_head(&req->hash_node, list);
5098 }
5099 
__io_arm_poll_handler(struct io_kiocb * req,struct io_poll_iocb * poll,struct io_poll_table * ipt,__poll_t mask,wait_queue_func_t wake_func)5100 static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
5101 				      struct io_poll_iocb *poll,
5102 				      struct io_poll_table *ipt, __poll_t mask,
5103 				      wait_queue_func_t wake_func)
5104 	__acquires(&ctx->completion_lock)
5105 {
5106 	struct io_ring_ctx *ctx = req->ctx;
5107 	bool cancel = false;
5108 
5109 	INIT_HLIST_NODE(&req->hash_node);
5110 	io_init_poll_iocb(poll, mask, wake_func);
5111 	poll->file = req->file;
5112 	poll->wait.private = req;
5113 
5114 	ipt->pt._key = mask;
5115 	ipt->req = req;
5116 	ipt->error = -EINVAL;
5117 
5118 	mask = vfs_poll(req->file, &ipt->pt) & poll->events;
5119 
5120 	spin_lock_irq(&ctx->completion_lock);
5121 	if (likely(poll->head)) {
5122 		spin_lock(&poll->head->lock);
5123 		if (unlikely(list_empty(&poll->wait.entry))) {
5124 			if (ipt->error)
5125 				cancel = true;
5126 			ipt->error = 0;
5127 			mask = 0;
5128 		}
5129 		if ((mask && (poll->events & EPOLLONESHOT)) || ipt->error)
5130 			list_del_init(&poll->wait.entry);
5131 		else if (cancel)
5132 			WRITE_ONCE(poll->canceled, true);
5133 		else if (!poll->done) /* actually waiting for an event */
5134 			io_poll_req_insert(req);
5135 		spin_unlock(&poll->head->lock);
5136 	}
5137 
5138 	return mask;
5139 }
5140 
io_arm_poll_handler(struct io_kiocb * req)5141 static bool io_arm_poll_handler(struct io_kiocb *req)
5142 {
5143 	const struct io_op_def *def = &io_op_defs[req->opcode];
5144 	struct io_ring_ctx *ctx = req->ctx;
5145 	struct async_poll *apoll;
5146 	struct io_poll_table ipt;
5147 	__poll_t mask, ret;
5148 	int rw;
5149 
5150 	if (!req->file || !file_can_poll(req->file))
5151 		return false;
5152 	if (req->flags & REQ_F_POLLED)
5153 		return false;
5154 	if (def->pollin)
5155 		rw = READ;
5156 	else if (def->pollout)
5157 		rw = WRITE;
5158 	else
5159 		return false;
5160 	/* if we can't nonblock try, then no point in arming a poll handler */
5161 	if (!io_file_supports_async(req, rw))
5162 		return false;
5163 
5164 	apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
5165 	if (unlikely(!apoll))
5166 		return false;
5167 	apoll->double_poll = NULL;
5168 
5169 	req->flags |= REQ_F_POLLED;
5170 	req->apoll = apoll;
5171 
5172 	mask = EPOLLONESHOT;
5173 	if (def->pollin)
5174 		mask |= POLLIN | POLLRDNORM;
5175 	if (def->pollout)
5176 		mask |= POLLOUT | POLLWRNORM;
5177 
5178 	/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
5179 	if ((req->opcode == IORING_OP_RECVMSG) &&
5180 	    (req->sr_msg.msg_flags & MSG_ERRQUEUE))
5181 		mask &= ~POLLIN;
5182 
5183 	mask |= POLLERR | POLLPRI;
5184 
5185 	ipt.pt._qproc = io_async_queue_proc;
5186 
5187 	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
5188 					io_async_wake);
5189 	if (ret || ipt.error) {
5190 		io_poll_remove_double(req);
5191 		spin_unlock_irq(&ctx->completion_lock);
5192 		return false;
5193 	}
5194 	spin_unlock_irq(&ctx->completion_lock);
5195 	trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask,
5196 					apoll->poll.events);
5197 	return true;
5198 }
5199 
__io_poll_remove_one(struct io_kiocb * req,struct io_poll_iocb * poll,bool do_cancel)5200 static bool __io_poll_remove_one(struct io_kiocb *req,
5201 				 struct io_poll_iocb *poll, bool do_cancel)
5202 	__must_hold(&req->ctx->completion_lock)
5203 {
5204 	bool do_complete = false;
5205 
5206 	if (!poll->head)
5207 		return false;
5208 	spin_lock(&poll->head->lock);
5209 	if (do_cancel)
5210 		WRITE_ONCE(poll->canceled, true);
5211 	if (!list_empty(&poll->wait.entry)) {
5212 		list_del_init(&poll->wait.entry);
5213 		do_complete = true;
5214 	}
5215 	spin_unlock(&poll->head->lock);
5216 	hash_del(&req->hash_node);
5217 	return do_complete;
5218 }
5219 
io_poll_remove_waitqs(struct io_kiocb * req)5220 static bool io_poll_remove_waitqs(struct io_kiocb *req)
5221 	__must_hold(&req->ctx->completion_lock)
5222 {
5223 	bool do_complete;
5224 
5225 	io_poll_remove_double(req);
5226 	do_complete = __io_poll_remove_one(req, io_poll_get_single(req), true);
5227 
5228 	if (req->opcode != IORING_OP_POLL_ADD && do_complete) {
5229 		/* non-poll requests have submit ref still */
5230 		req_ref_put(req);
5231 	}
5232 	return do_complete;
5233 }
5234 
io_poll_remove_one(struct io_kiocb * req)5235 static bool io_poll_remove_one(struct io_kiocb *req)
5236 	__must_hold(&req->ctx->completion_lock)
5237 {
5238 	bool do_complete;
5239 
5240 	do_complete = io_poll_remove_waitqs(req);
5241 	if (do_complete) {
5242 		io_cqring_fill_event(req->ctx, req->user_data, -ECANCELED, 0);
5243 		io_commit_cqring(req->ctx);
5244 		req_set_fail_links(req);
5245 		io_put_req_deferred(req, 1);
5246 	}
5247 
5248 	return do_complete;
5249 }
5250 
5251 /*
5252  * Returns true if we found and killed one or more poll requests
5253  */
io_poll_remove_all(struct io_ring_ctx * ctx,struct task_struct * tsk,struct files_struct * files)5254 static bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
5255 			       struct files_struct *files)
5256 {
5257 	struct hlist_node *tmp;
5258 	struct io_kiocb *req;
5259 	int posted = 0, i;
5260 
5261 	spin_lock_irq(&ctx->completion_lock);
5262 	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
5263 		struct hlist_head *list;
5264 
5265 		list = &ctx->cancel_hash[i];
5266 		hlist_for_each_entry_safe(req, tmp, list, hash_node) {
5267 			if (io_match_task(req, tsk, files))
5268 				posted += io_poll_remove_one(req);
5269 		}
5270 	}
5271 	spin_unlock_irq(&ctx->completion_lock);
5272 
5273 	if (posted)
5274 		io_cqring_ev_posted(ctx);
5275 
5276 	return posted != 0;
5277 }
5278 
io_poll_find(struct io_ring_ctx * ctx,__u64 sqe_addr,bool poll_only)5279 static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, __u64 sqe_addr,
5280 				     bool poll_only)
5281 	__must_hold(&ctx->completion_lock)
5282 {
5283 	struct hlist_head *list;
5284 	struct io_kiocb *req;
5285 
5286 	list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
5287 	hlist_for_each_entry(req, list, hash_node) {
5288 		if (sqe_addr != req->user_data)
5289 			continue;
5290 		if (poll_only && req->opcode != IORING_OP_POLL_ADD)
5291 			continue;
5292 		return req;
5293 	}
5294 	return NULL;
5295 }
5296 
io_poll_cancel(struct io_ring_ctx * ctx,__u64 sqe_addr,bool poll_only)5297 static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr,
5298 			  bool poll_only)
5299 	__must_hold(&ctx->completion_lock)
5300 {
5301 	struct io_kiocb *req;
5302 
5303 	req = io_poll_find(ctx, sqe_addr, poll_only);
5304 	if (!req)
5305 		return -ENOENT;
5306 	if (io_poll_remove_one(req))
5307 		return 0;
5308 
5309 	return -EALREADY;
5310 }
5311 
io_poll_parse_events(const struct io_uring_sqe * sqe,unsigned int flags)5312 static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
5313 				     unsigned int flags)
5314 {
5315 	u32 events;
5316 
5317 	events = READ_ONCE(sqe->poll32_events);
5318 #ifdef __BIG_ENDIAN
5319 	events = swahw32(events);
5320 #endif
5321 	if (!(flags & IORING_POLL_ADD_MULTI))
5322 		events |= EPOLLONESHOT;
5323 	return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT));
5324 }
5325 
io_poll_update_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5326 static int io_poll_update_prep(struct io_kiocb *req,
5327 			       const struct io_uring_sqe *sqe)
5328 {
5329 	struct io_poll_update *upd = &req->poll_update;
5330 	u32 flags;
5331 
5332 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5333 		return -EINVAL;
5334 	if (sqe->ioprio || sqe->buf_index)
5335 		return -EINVAL;
5336 	flags = READ_ONCE(sqe->len);
5337 	if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
5338 		      IORING_POLL_ADD_MULTI))
5339 		return -EINVAL;
5340 	/* meaningless without update */
5341 	if (flags == IORING_POLL_ADD_MULTI)
5342 		return -EINVAL;
5343 
5344 	upd->old_user_data = READ_ONCE(sqe->addr);
5345 	upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
5346 	upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
5347 
5348 	upd->new_user_data = READ_ONCE(sqe->off);
5349 	if (!upd->update_user_data && upd->new_user_data)
5350 		return -EINVAL;
5351 	if (upd->update_events)
5352 		upd->events = io_poll_parse_events(sqe, flags);
5353 	else if (sqe->poll32_events)
5354 		return -EINVAL;
5355 
5356 	return 0;
5357 }
5358 
io_poll_wake(struct wait_queue_entry * wait,unsigned mode,int sync,void * key)5359 static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
5360 			void *key)
5361 {
5362 	struct io_kiocb *req = wait->private;
5363 	struct io_poll_iocb *poll = &req->poll;
5364 
5365 	return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func);
5366 }
5367 
io_poll_queue_proc(struct file * file,struct wait_queue_head * head,struct poll_table_struct * p)5368 static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
5369 			       struct poll_table_struct *p)
5370 {
5371 	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
5372 
5373 	__io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->async_data);
5374 }
5375 
io_poll_add_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5376 static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
5377 {
5378 	struct io_poll_iocb *poll = &req->poll;
5379 	u32 flags;
5380 
5381 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5382 		return -EINVAL;
5383 	if (sqe->ioprio || sqe->buf_index || sqe->off || sqe->addr)
5384 		return -EINVAL;
5385 	flags = READ_ONCE(sqe->len);
5386 	if (flags & ~IORING_POLL_ADD_MULTI)
5387 		return -EINVAL;
5388 
5389 	poll->events = io_poll_parse_events(sqe, flags);
5390 	return 0;
5391 }
5392 
io_poll_add(struct io_kiocb * req,unsigned int issue_flags)5393 static int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
5394 {
5395 	struct io_poll_iocb *poll = &req->poll;
5396 	struct io_ring_ctx *ctx = req->ctx;
5397 	struct io_poll_table ipt;
5398 	__poll_t mask;
5399 
5400 	ipt.pt._qproc = io_poll_queue_proc;
5401 
5402 	mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events,
5403 					io_poll_wake);
5404 
5405 	if (mask) { /* no async, we'd stolen it */
5406 		ipt.error = 0;
5407 		io_poll_complete(req, mask);
5408 	}
5409 	spin_unlock_irq(&ctx->completion_lock);
5410 
5411 	if (mask) {
5412 		io_cqring_ev_posted(ctx);
5413 		if (poll->events & EPOLLONESHOT)
5414 			io_put_req(req);
5415 	}
5416 	return ipt.error;
5417 }
5418 
io_poll_update(struct io_kiocb * req,unsigned int issue_flags)5419 static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
5420 {
5421 	struct io_ring_ctx *ctx = req->ctx;
5422 	struct io_kiocb *preq;
5423 	bool completing;
5424 	int ret;
5425 
5426 	spin_lock_irq(&ctx->completion_lock);
5427 	preq = io_poll_find(ctx, req->poll_update.old_user_data, true);
5428 	if (!preq) {
5429 		ret = -ENOENT;
5430 		goto err;
5431 	}
5432 
5433 	if (!req->poll_update.update_events && !req->poll_update.update_user_data) {
5434 		completing = true;
5435 		ret = io_poll_remove_one(preq) ? 0 : -EALREADY;
5436 		goto err;
5437 	}
5438 
5439 	/*
5440 	 * Don't allow racy completion with singleshot, as we cannot safely
5441 	 * update those. For multishot, if we're racing with completion, just
5442 	 * let completion re-add it.
5443 	 */
5444 	completing = !__io_poll_remove_one(preq, &preq->poll, false);
5445 	if (completing && (preq->poll.events & EPOLLONESHOT)) {
5446 		ret = -EALREADY;
5447 		goto err;
5448 	}
5449 	/* we now have a detached poll request. reissue. */
5450 	ret = 0;
5451 err:
5452 	if (ret < 0) {
5453 		spin_unlock_irq(&ctx->completion_lock);
5454 		req_set_fail_links(req);
5455 		io_req_complete(req, ret);
5456 		return 0;
5457 	}
5458 	/* only mask one event flags, keep behavior flags */
5459 	if (req->poll_update.update_events) {
5460 		preq->poll.events &= ~0xffff;
5461 		preq->poll.events |= req->poll_update.events & 0xffff;
5462 		preq->poll.events |= IO_POLL_UNMASK;
5463 	}
5464 	if (req->poll_update.update_user_data)
5465 		preq->user_data = req->poll_update.new_user_data;
5466 	spin_unlock_irq(&ctx->completion_lock);
5467 
5468 	/* complete update request, we're done with it */
5469 	io_req_complete(req, ret);
5470 
5471 	if (!completing) {
5472 		ret = io_poll_add(preq, issue_flags);
5473 		if (ret < 0) {
5474 			req_set_fail_links(preq);
5475 			io_req_complete(preq, ret);
5476 		}
5477 	}
5478 	return 0;
5479 }
5480 
io_timeout_fn(struct hrtimer * timer)5481 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
5482 {
5483 	struct io_timeout_data *data = container_of(timer,
5484 						struct io_timeout_data, timer);
5485 	struct io_kiocb *req = data->req;
5486 	struct io_ring_ctx *ctx = req->ctx;
5487 	unsigned long flags;
5488 
5489 	spin_lock_irqsave(&ctx->completion_lock, flags);
5490 	list_del_init(&req->timeout.list);
5491 	atomic_set(&req->ctx->cq_timeouts,
5492 		atomic_read(&req->ctx->cq_timeouts) + 1);
5493 
5494 	io_cqring_fill_event(ctx, req->user_data, -ETIME, 0);
5495 	io_commit_cqring(ctx);
5496 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
5497 
5498 	io_cqring_ev_posted(ctx);
5499 	req_set_fail_links(req);
5500 	io_put_req(req);
5501 	return HRTIMER_NORESTART;
5502 }
5503 
io_timeout_extract(struct io_ring_ctx * ctx,__u64 user_data)5504 static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
5505 					   __u64 user_data)
5506 	__must_hold(&ctx->completion_lock)
5507 {
5508 	struct io_timeout_data *io;
5509 	struct io_kiocb *req;
5510 	bool found = false;
5511 
5512 	list_for_each_entry(req, &ctx->timeout_list, timeout.list) {
5513 		found = user_data == req->user_data;
5514 		if (found)
5515 			break;
5516 	}
5517 	if (!found)
5518 		return ERR_PTR(-ENOENT);
5519 
5520 	io = req->async_data;
5521 	if (hrtimer_try_to_cancel(&io->timer) == -1)
5522 		return ERR_PTR(-EALREADY);
5523 	list_del_init(&req->timeout.list);
5524 	return req;
5525 }
5526 
io_timeout_cancel(struct io_ring_ctx * ctx,__u64 user_data)5527 static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
5528 	__must_hold(&ctx->completion_lock)
5529 {
5530 	struct io_kiocb *req = io_timeout_extract(ctx, user_data);
5531 
5532 	if (IS_ERR(req))
5533 		return PTR_ERR(req);
5534 
5535 	req_set_fail_links(req);
5536 	io_cqring_fill_event(ctx, req->user_data, -ECANCELED, 0);
5537 	io_put_req_deferred(req, 1);
5538 	return 0;
5539 }
5540 
io_timeout_update(struct io_ring_ctx * ctx,__u64 user_data,struct timespec64 * ts,enum hrtimer_mode mode)5541 static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
5542 			     struct timespec64 *ts, enum hrtimer_mode mode)
5543 	__must_hold(&ctx->completion_lock)
5544 {
5545 	struct io_kiocb *req = io_timeout_extract(ctx, user_data);
5546 	struct io_timeout_data *data;
5547 
5548 	if (IS_ERR(req))
5549 		return PTR_ERR(req);
5550 
5551 	req->timeout.off = 0; /* noseq */
5552 	data = req->async_data;
5553 	list_add_tail(&req->timeout.list, &ctx->timeout_list);
5554 	hrtimer_init(&data->timer, CLOCK_MONOTONIC, mode);
5555 	data->timer.function = io_timeout_fn;
5556 	hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
5557 	return 0;
5558 }
5559 
io_timeout_remove_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5560 static int io_timeout_remove_prep(struct io_kiocb *req,
5561 				  const struct io_uring_sqe *sqe)
5562 {
5563 	struct io_timeout_rem *tr = &req->timeout_rem;
5564 
5565 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5566 		return -EINVAL;
5567 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5568 		return -EINVAL;
5569 	if (sqe->ioprio || sqe->buf_index || sqe->len)
5570 		return -EINVAL;
5571 
5572 	tr->addr = READ_ONCE(sqe->addr);
5573 	tr->flags = READ_ONCE(sqe->timeout_flags);
5574 	if (tr->flags & IORING_TIMEOUT_UPDATE) {
5575 		if (tr->flags & ~(IORING_TIMEOUT_UPDATE|IORING_TIMEOUT_ABS))
5576 			return -EINVAL;
5577 		if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
5578 			return -EFAULT;
5579 	} else if (tr->flags) {
5580 		/* timeout removal doesn't support flags */
5581 		return -EINVAL;
5582 	}
5583 
5584 	return 0;
5585 }
5586 
io_translate_timeout_mode(unsigned int flags)5587 static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
5588 {
5589 	return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
5590 					    : HRTIMER_MODE_REL;
5591 }
5592 
5593 /*
5594  * Remove or update an existing timeout command
5595  */
io_timeout_remove(struct io_kiocb * req,unsigned int issue_flags)5596 static int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
5597 {
5598 	struct io_timeout_rem *tr = &req->timeout_rem;
5599 	struct io_ring_ctx *ctx = req->ctx;
5600 	int ret;
5601 
5602 	spin_lock_irq(&ctx->completion_lock);
5603 	if (!(req->timeout_rem.flags & IORING_TIMEOUT_UPDATE))
5604 		ret = io_timeout_cancel(ctx, tr->addr);
5605 	else
5606 		ret = io_timeout_update(ctx, tr->addr, &tr->ts,
5607 					io_translate_timeout_mode(tr->flags));
5608 
5609 	io_cqring_fill_event(ctx, req->user_data, ret, 0);
5610 	io_commit_cqring(ctx);
5611 	spin_unlock_irq(&ctx->completion_lock);
5612 	io_cqring_ev_posted(ctx);
5613 	if (ret < 0)
5614 		req_set_fail_links(req);
5615 	io_put_req(req);
5616 	return 0;
5617 }
5618 
io_timeout_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe,bool is_timeout_link)5619 static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
5620 			   bool is_timeout_link)
5621 {
5622 	struct io_timeout_data *data;
5623 	unsigned flags;
5624 	u32 off = READ_ONCE(sqe->off);
5625 
5626 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5627 		return -EINVAL;
5628 	if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
5629 		return -EINVAL;
5630 	if (off && is_timeout_link)
5631 		return -EINVAL;
5632 	flags = READ_ONCE(sqe->timeout_flags);
5633 	if (flags & ~IORING_TIMEOUT_ABS)
5634 		return -EINVAL;
5635 
5636 	req->timeout.off = off;
5637 
5638 	if (!req->async_data && io_alloc_async_data(req))
5639 		return -ENOMEM;
5640 
5641 	data = req->async_data;
5642 	data->req = req;
5643 
5644 	if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
5645 		return -EFAULT;
5646 
5647 	data->mode = io_translate_timeout_mode(flags);
5648 	hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
5649 	if (is_timeout_link)
5650 		io_req_track_inflight(req);
5651 	return 0;
5652 }
5653 
io_timeout(struct io_kiocb * req,unsigned int issue_flags)5654 static int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
5655 {
5656 	struct io_ring_ctx *ctx = req->ctx;
5657 	struct io_timeout_data *data = req->async_data;
5658 	struct list_head *entry;
5659 	u32 tail, off = req->timeout.off;
5660 
5661 	spin_lock_irq(&ctx->completion_lock);
5662 
5663 	/*
5664 	 * sqe->off holds how many events that need to occur for this
5665 	 * timeout event to be satisfied. If it isn't set, then this is
5666 	 * a pure timeout request, sequence isn't used.
5667 	 */
5668 	if (io_is_timeout_noseq(req)) {
5669 		entry = ctx->timeout_list.prev;
5670 		goto add;
5671 	}
5672 
5673 	tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
5674 	req->timeout.target_seq = tail + off;
5675 
5676 	/* Update the last seq here in case io_flush_timeouts() hasn't.
5677 	 * This is safe because ->completion_lock is held, and submissions
5678 	 * and completions are never mixed in the same ->completion_lock section.
5679 	 */
5680 	ctx->cq_last_tm_flush = tail;
5681 
5682 	/*
5683 	 * Insertion sort, ensuring the first entry in the list is always
5684 	 * the one we need first.
5685 	 */
5686 	list_for_each_prev(entry, &ctx->timeout_list) {
5687 		struct io_kiocb *nxt = list_entry(entry, struct io_kiocb,
5688 						  timeout.list);
5689 
5690 		if (io_is_timeout_noseq(nxt))
5691 			continue;
5692 		/* nxt.seq is behind @tail, otherwise would've been completed */
5693 		if (off >= nxt->timeout.target_seq - tail)
5694 			break;
5695 	}
5696 add:
5697 	list_add(&req->timeout.list, entry);
5698 	data->timer.function = io_timeout_fn;
5699 	hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
5700 	spin_unlock_irq(&ctx->completion_lock);
5701 	return 0;
5702 }
5703 
5704 struct io_cancel_data {
5705 	struct io_ring_ctx *ctx;
5706 	u64 user_data;
5707 };
5708 
io_cancel_cb(struct io_wq_work * work,void * data)5709 static bool io_cancel_cb(struct io_wq_work *work, void *data)
5710 {
5711 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
5712 	struct io_cancel_data *cd = data;
5713 
5714 	return req->ctx == cd->ctx && req->user_data == cd->user_data;
5715 }
5716 
io_async_cancel_one(struct io_uring_task * tctx,u64 user_data,struct io_ring_ctx * ctx)5717 static int io_async_cancel_one(struct io_uring_task *tctx, u64 user_data,
5718 			       struct io_ring_ctx *ctx)
5719 {
5720 	struct io_cancel_data data = { .ctx = ctx, .user_data = user_data, };
5721 	enum io_wq_cancel cancel_ret;
5722 	int ret = 0;
5723 
5724 	if (!tctx || !tctx->io_wq)
5725 		return -ENOENT;
5726 
5727 	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, &data, false);
5728 	switch (cancel_ret) {
5729 	case IO_WQ_CANCEL_OK:
5730 		ret = 0;
5731 		break;
5732 	case IO_WQ_CANCEL_RUNNING:
5733 		ret = -EALREADY;
5734 		break;
5735 	case IO_WQ_CANCEL_NOTFOUND:
5736 		ret = -ENOENT;
5737 		break;
5738 	}
5739 
5740 	return ret;
5741 }
5742 
io_async_find_and_cancel(struct io_ring_ctx * ctx,struct io_kiocb * req,__u64 sqe_addr,int success_ret)5743 static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
5744 				     struct io_kiocb *req, __u64 sqe_addr,
5745 				     int success_ret)
5746 {
5747 	unsigned long flags;
5748 	int ret;
5749 
5750 	ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
5751 	spin_lock_irqsave(&ctx->completion_lock, flags);
5752 	if (ret != -ENOENT)
5753 		goto done;
5754 	ret = io_timeout_cancel(ctx, sqe_addr);
5755 	if (ret != -ENOENT)
5756 		goto done;
5757 	ret = io_poll_cancel(ctx, sqe_addr, false);
5758 done:
5759 	if (!ret)
5760 		ret = success_ret;
5761 	io_cqring_fill_event(ctx, req->user_data, ret, 0);
5762 	io_commit_cqring(ctx);
5763 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
5764 	io_cqring_ev_posted(ctx);
5765 
5766 	if (ret < 0)
5767 		req_set_fail_links(req);
5768 }
5769 
io_async_cancel_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5770 static int io_async_cancel_prep(struct io_kiocb *req,
5771 				const struct io_uring_sqe *sqe)
5772 {
5773 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5774 		return -EINVAL;
5775 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5776 		return -EINVAL;
5777 	if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags)
5778 		return -EINVAL;
5779 
5780 	req->cancel.addr = READ_ONCE(sqe->addr);
5781 	return 0;
5782 }
5783 
io_async_cancel(struct io_kiocb * req,unsigned int issue_flags)5784 static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
5785 {
5786 	struct io_ring_ctx *ctx = req->ctx;
5787 	u64 sqe_addr = req->cancel.addr;
5788 	struct io_tctx_node *node;
5789 	int ret;
5790 
5791 	/* tasks should wait for their io-wq threads, so safe w/o sync */
5792 	ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
5793 	spin_lock_irq(&ctx->completion_lock);
5794 	if (ret != -ENOENT)
5795 		goto done;
5796 	ret = io_timeout_cancel(ctx, sqe_addr);
5797 	if (ret != -ENOENT)
5798 		goto done;
5799 	ret = io_poll_cancel(ctx, sqe_addr, false);
5800 	if (ret != -ENOENT)
5801 		goto done;
5802 	spin_unlock_irq(&ctx->completion_lock);
5803 
5804 	/* slow path, try all io-wq's */
5805 	io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
5806 	ret = -ENOENT;
5807 	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
5808 		struct io_uring_task *tctx = node->task->io_uring;
5809 
5810 		ret = io_async_cancel_one(tctx, req->cancel.addr, ctx);
5811 		if (ret != -ENOENT)
5812 			break;
5813 	}
5814 	io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
5815 
5816 	spin_lock_irq(&ctx->completion_lock);
5817 done:
5818 	io_cqring_fill_event(ctx, req->user_data, ret, 0);
5819 	io_commit_cqring(ctx);
5820 	spin_unlock_irq(&ctx->completion_lock);
5821 	io_cqring_ev_posted(ctx);
5822 
5823 	if (ret < 0)
5824 		req_set_fail_links(req);
5825 	io_put_req(req);
5826 	return 0;
5827 }
5828 
io_rsrc_update_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5829 static int io_rsrc_update_prep(struct io_kiocb *req,
5830 				const struct io_uring_sqe *sqe)
5831 {
5832 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5833 		return -EINVAL;
5834 	if (sqe->ioprio || sqe->rw_flags)
5835 		return -EINVAL;
5836 
5837 	req->rsrc_update.offset = READ_ONCE(sqe->off);
5838 	req->rsrc_update.nr_args = READ_ONCE(sqe->len);
5839 	if (!req->rsrc_update.nr_args)
5840 		return -EINVAL;
5841 	req->rsrc_update.arg = READ_ONCE(sqe->addr);
5842 	return 0;
5843 }
5844 
io_files_update(struct io_kiocb * req,unsigned int issue_flags)5845 static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
5846 {
5847 	struct io_ring_ctx *ctx = req->ctx;
5848 	struct io_uring_rsrc_update2 up;
5849 	int ret;
5850 
5851 	if (issue_flags & IO_URING_F_NONBLOCK)
5852 		return -EAGAIN;
5853 
5854 	up.offset = req->rsrc_update.offset;
5855 	up.data = req->rsrc_update.arg;
5856 	up.nr = 0;
5857 	up.tags = 0;
5858 	up.resv = 0;
5859 
5860 	mutex_lock(&ctx->uring_lock);
5861 	ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
5862 					&up, req->rsrc_update.nr_args);
5863 	mutex_unlock(&ctx->uring_lock);
5864 
5865 	if (ret < 0)
5866 		req_set_fail_links(req);
5867 	__io_req_complete(req, issue_flags, ret, 0);
5868 	return 0;
5869 }
5870 
io_req_prep(struct io_kiocb * req,const struct io_uring_sqe * sqe)5871 static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
5872 {
5873 	switch (req->opcode) {
5874 	case IORING_OP_NOP:
5875 		return 0;
5876 	case IORING_OP_READV:
5877 	case IORING_OP_READ_FIXED:
5878 	case IORING_OP_READ:
5879 		return io_read_prep(req, sqe);
5880 	case IORING_OP_WRITEV:
5881 	case IORING_OP_WRITE_FIXED:
5882 	case IORING_OP_WRITE:
5883 		return io_write_prep(req, sqe);
5884 	case IORING_OP_POLL_ADD:
5885 		return io_poll_add_prep(req, sqe);
5886 	case IORING_OP_POLL_REMOVE:
5887 		return io_poll_update_prep(req, sqe);
5888 	case IORING_OP_FSYNC:
5889 		return io_fsync_prep(req, sqe);
5890 	case IORING_OP_SYNC_FILE_RANGE:
5891 		return io_sfr_prep(req, sqe);
5892 	case IORING_OP_SENDMSG:
5893 	case IORING_OP_SEND:
5894 		return io_sendmsg_prep(req, sqe);
5895 	case IORING_OP_RECVMSG:
5896 	case IORING_OP_RECV:
5897 		return io_recvmsg_prep(req, sqe);
5898 	case IORING_OP_CONNECT:
5899 		return io_connect_prep(req, sqe);
5900 	case IORING_OP_TIMEOUT:
5901 		return io_timeout_prep(req, sqe, false);
5902 	case IORING_OP_TIMEOUT_REMOVE:
5903 		return io_timeout_remove_prep(req, sqe);
5904 	case IORING_OP_ASYNC_CANCEL:
5905 		return io_async_cancel_prep(req, sqe);
5906 	case IORING_OP_LINK_TIMEOUT:
5907 		return io_timeout_prep(req, sqe, true);
5908 	case IORING_OP_ACCEPT:
5909 		return io_accept_prep(req, sqe);
5910 	case IORING_OP_FALLOCATE:
5911 		return io_fallocate_prep(req, sqe);
5912 	case IORING_OP_OPENAT:
5913 		return io_openat_prep(req, sqe);
5914 	case IORING_OP_CLOSE:
5915 		return io_close_prep(req, sqe);
5916 	case IORING_OP_FILES_UPDATE:
5917 		return io_rsrc_update_prep(req, sqe);
5918 	case IORING_OP_STATX:
5919 		return io_statx_prep(req, sqe);
5920 	case IORING_OP_FADVISE:
5921 		return io_fadvise_prep(req, sqe);
5922 	case IORING_OP_MADVISE:
5923 		return io_madvise_prep(req, sqe);
5924 	case IORING_OP_OPENAT2:
5925 		return io_openat2_prep(req, sqe);
5926 	case IORING_OP_EPOLL_CTL:
5927 		return io_epoll_ctl_prep(req, sqe);
5928 	case IORING_OP_SPLICE:
5929 		return io_splice_prep(req, sqe);
5930 	case IORING_OP_PROVIDE_BUFFERS:
5931 		return io_provide_buffers_prep(req, sqe);
5932 	case IORING_OP_REMOVE_BUFFERS:
5933 		return io_remove_buffers_prep(req, sqe);
5934 	case IORING_OP_TEE:
5935 		return io_tee_prep(req, sqe);
5936 	case IORING_OP_SHUTDOWN:
5937 		return io_shutdown_prep(req, sqe);
5938 	case IORING_OP_RENAMEAT:
5939 		return io_renameat_prep(req, sqe);
5940 	case IORING_OP_UNLINKAT:
5941 		return io_unlinkat_prep(req, sqe);
5942 	}
5943 
5944 	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
5945 			req->opcode);
5946 	return -EINVAL;
5947 }
5948 
io_req_prep_async(struct io_kiocb * req)5949 static int io_req_prep_async(struct io_kiocb *req)
5950 {
5951 	if (!io_op_defs[req->opcode].needs_async_setup)
5952 		return 0;
5953 	if (WARN_ON_ONCE(req->async_data))
5954 		return -EFAULT;
5955 	if (io_alloc_async_data(req))
5956 		return -EAGAIN;
5957 
5958 	switch (req->opcode) {
5959 	case IORING_OP_READV:
5960 		return io_rw_prep_async(req, READ);
5961 	case IORING_OP_WRITEV:
5962 		return io_rw_prep_async(req, WRITE);
5963 	case IORING_OP_SENDMSG:
5964 		return io_sendmsg_prep_async(req);
5965 	case IORING_OP_RECVMSG:
5966 		return io_recvmsg_prep_async(req);
5967 	case IORING_OP_CONNECT:
5968 		return io_connect_prep_async(req);
5969 	}
5970 	printk_once(KERN_WARNING "io_uring: prep_async() bad opcode %d\n",
5971 		    req->opcode);
5972 	return -EFAULT;
5973 }
5974 
io_get_sequence(struct io_kiocb * req)5975 static u32 io_get_sequence(struct io_kiocb *req)
5976 {
5977 	struct io_kiocb *pos;
5978 	struct io_ring_ctx *ctx = req->ctx;
5979 	u32 total_submitted, nr_reqs = 0;
5980 
5981 	io_for_each_link(pos, req)
5982 		nr_reqs++;
5983 
5984 	total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped;
5985 	return total_submitted - nr_reqs;
5986 }
5987 
io_req_defer(struct io_kiocb * req)5988 static int io_req_defer(struct io_kiocb *req)
5989 {
5990 	struct io_ring_ctx *ctx = req->ctx;
5991 	struct io_defer_entry *de;
5992 	int ret;
5993 	u32 seq;
5994 
5995 	/* Still need defer if there is pending req in defer list. */
5996 	if (likely(list_empty_careful(&ctx->defer_list) &&
5997 		!(req->flags & REQ_F_IO_DRAIN)))
5998 		return 0;
5999 
6000 	seq = io_get_sequence(req);
6001 	/* Still a chance to pass the sequence check */
6002 	if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list))
6003 		return 0;
6004 
6005 	ret = io_req_prep_async(req);
6006 	if (ret)
6007 		return ret;
6008 	io_prep_async_link(req);
6009 	de = kmalloc(sizeof(*de), GFP_KERNEL);
6010 	if (!de)
6011 		return -ENOMEM;
6012 
6013 	spin_lock_irq(&ctx->completion_lock);
6014 	if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
6015 		spin_unlock_irq(&ctx->completion_lock);
6016 		kfree(de);
6017 		io_queue_async_work(req);
6018 		return -EIOCBQUEUED;
6019 	}
6020 
6021 	trace_io_uring_defer(ctx, req, req->user_data);
6022 	de->req = req;
6023 	de->seq = seq;
6024 	list_add_tail(&de->list, &ctx->defer_list);
6025 	spin_unlock_irq(&ctx->completion_lock);
6026 	return -EIOCBQUEUED;
6027 }
6028 
io_clean_op(struct io_kiocb * req)6029 static void io_clean_op(struct io_kiocb *req)
6030 {
6031 	if (req->flags & REQ_F_BUFFER_SELECTED) {
6032 		switch (req->opcode) {
6033 		case IORING_OP_READV:
6034 		case IORING_OP_READ_FIXED:
6035 		case IORING_OP_READ:
6036 			kfree((void *)(unsigned long)req->rw.addr);
6037 			break;
6038 		case IORING_OP_RECVMSG:
6039 		case IORING_OP_RECV:
6040 			kfree(req->sr_msg.kbuf);
6041 			break;
6042 		}
6043 		req->flags &= ~REQ_F_BUFFER_SELECTED;
6044 	}
6045 
6046 	if (req->flags & REQ_F_NEED_CLEANUP) {
6047 		switch (req->opcode) {
6048 		case IORING_OP_READV:
6049 		case IORING_OP_READ_FIXED:
6050 		case IORING_OP_READ:
6051 		case IORING_OP_WRITEV:
6052 		case IORING_OP_WRITE_FIXED:
6053 		case IORING_OP_WRITE: {
6054 			struct io_async_rw *io = req->async_data;
6055 			if (io->free_iovec)
6056 				kfree(io->free_iovec);
6057 			break;
6058 			}
6059 		case IORING_OP_RECVMSG:
6060 		case IORING_OP_SENDMSG: {
6061 			struct io_async_msghdr *io = req->async_data;
6062 
6063 			kfree(io->free_iov);
6064 			break;
6065 			}
6066 		case IORING_OP_SPLICE:
6067 		case IORING_OP_TEE:
6068 			if (!(req->splice.flags & SPLICE_F_FD_IN_FIXED))
6069 				io_put_file(req->splice.file_in);
6070 			break;
6071 		case IORING_OP_OPENAT:
6072 		case IORING_OP_OPENAT2:
6073 			if (req->open.filename)
6074 				putname(req->open.filename);
6075 			break;
6076 		case IORING_OP_RENAMEAT:
6077 			putname(req->rename.oldpath);
6078 			putname(req->rename.newpath);
6079 			break;
6080 		case IORING_OP_UNLINKAT:
6081 			putname(req->unlink.filename);
6082 			break;
6083 		}
6084 		req->flags &= ~REQ_F_NEED_CLEANUP;
6085 	}
6086 	if ((req->flags & REQ_F_POLLED) && req->apoll) {
6087 		kfree(req->apoll->double_poll);
6088 		kfree(req->apoll);
6089 		req->apoll = NULL;
6090 	}
6091 	if (req->flags & REQ_F_INFLIGHT) {
6092 		struct io_uring_task *tctx = req->task->io_uring;
6093 
6094 		atomic_dec(&tctx->inflight_tracked);
6095 		req->flags &= ~REQ_F_INFLIGHT;
6096 	}
6097 }
6098 
io_issue_sqe(struct io_kiocb * req,unsigned int issue_flags)6099 static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
6100 {
6101 	struct io_ring_ctx *ctx = req->ctx;
6102 	const struct cred *creds = NULL;
6103 	int ret;
6104 
6105 	if (req->work.creds && req->work.creds != current_cred())
6106 		creds = override_creds(req->work.creds);
6107 
6108 	switch (req->opcode) {
6109 	case IORING_OP_NOP:
6110 		ret = io_nop(req, issue_flags);
6111 		break;
6112 	case IORING_OP_READV:
6113 	case IORING_OP_READ_FIXED:
6114 	case IORING_OP_READ:
6115 		ret = io_read(req, issue_flags);
6116 		break;
6117 	case IORING_OP_WRITEV:
6118 	case IORING_OP_WRITE_FIXED:
6119 	case IORING_OP_WRITE:
6120 		ret = io_write(req, issue_flags);
6121 		break;
6122 	case IORING_OP_FSYNC:
6123 		ret = io_fsync(req, issue_flags);
6124 		break;
6125 	case IORING_OP_POLL_ADD:
6126 		ret = io_poll_add(req, issue_flags);
6127 		break;
6128 	case IORING_OP_POLL_REMOVE:
6129 		ret = io_poll_update(req, issue_flags);
6130 		break;
6131 	case IORING_OP_SYNC_FILE_RANGE:
6132 		ret = io_sync_file_range(req, issue_flags);
6133 		break;
6134 	case IORING_OP_SENDMSG:
6135 		ret = io_sendmsg(req, issue_flags);
6136 		break;
6137 	case IORING_OP_SEND:
6138 		ret = io_send(req, issue_flags);
6139 		break;
6140 	case IORING_OP_RECVMSG:
6141 		ret = io_recvmsg(req, issue_flags);
6142 		break;
6143 	case IORING_OP_RECV:
6144 		ret = io_recv(req, issue_flags);
6145 		break;
6146 	case IORING_OP_TIMEOUT:
6147 		ret = io_timeout(req, issue_flags);
6148 		break;
6149 	case IORING_OP_TIMEOUT_REMOVE:
6150 		ret = io_timeout_remove(req, issue_flags);
6151 		break;
6152 	case IORING_OP_ACCEPT:
6153 		ret = io_accept(req, issue_flags);
6154 		break;
6155 	case IORING_OP_CONNECT:
6156 		ret = io_connect(req, issue_flags);
6157 		break;
6158 	case IORING_OP_ASYNC_CANCEL:
6159 		ret = io_async_cancel(req, issue_flags);
6160 		break;
6161 	case IORING_OP_FALLOCATE:
6162 		ret = io_fallocate(req, issue_flags);
6163 		break;
6164 	case IORING_OP_OPENAT:
6165 		ret = io_openat(req, issue_flags);
6166 		break;
6167 	case IORING_OP_CLOSE:
6168 		ret = io_close(req, issue_flags);
6169 		break;
6170 	case IORING_OP_FILES_UPDATE:
6171 		ret = io_files_update(req, issue_flags);
6172 		break;
6173 	case IORING_OP_STATX:
6174 		ret = io_statx(req, issue_flags);
6175 		break;
6176 	case IORING_OP_FADVISE:
6177 		ret = io_fadvise(req, issue_flags);
6178 		break;
6179 	case IORING_OP_MADVISE:
6180 		ret = io_madvise(req, issue_flags);
6181 		break;
6182 	case IORING_OP_OPENAT2:
6183 		ret = io_openat2(req, issue_flags);
6184 		break;
6185 	case IORING_OP_EPOLL_CTL:
6186 		ret = io_epoll_ctl(req, issue_flags);
6187 		break;
6188 	case IORING_OP_SPLICE:
6189 		ret = io_splice(req, issue_flags);
6190 		break;
6191 	case IORING_OP_PROVIDE_BUFFERS:
6192 		ret = io_provide_buffers(req, issue_flags);
6193 		break;
6194 	case IORING_OP_REMOVE_BUFFERS:
6195 		ret = io_remove_buffers(req, issue_flags);
6196 		break;
6197 	case IORING_OP_TEE:
6198 		ret = io_tee(req, issue_flags);
6199 		break;
6200 	case IORING_OP_SHUTDOWN:
6201 		ret = io_shutdown(req, issue_flags);
6202 		break;
6203 	case IORING_OP_RENAMEAT:
6204 		ret = io_renameat(req, issue_flags);
6205 		break;
6206 	case IORING_OP_UNLINKAT:
6207 		ret = io_unlinkat(req, issue_flags);
6208 		break;
6209 	default:
6210 		ret = -EINVAL;
6211 		break;
6212 	}
6213 
6214 	if (creds)
6215 		revert_creds(creds);
6216 
6217 	if (ret)
6218 		return ret;
6219 
6220 	/* If the op doesn't have a file, we're not polling for it */
6221 	if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {
6222 		const bool in_async = io_wq_current_is_worker();
6223 
6224 		/* workqueue context doesn't hold uring_lock, grab it now */
6225 		if (in_async)
6226 			mutex_lock(&ctx->uring_lock);
6227 
6228 		io_iopoll_req_issued(req, in_async);
6229 
6230 		if (in_async)
6231 			mutex_unlock(&ctx->uring_lock);
6232 	}
6233 
6234 	return 0;
6235 }
6236 
io_wq_submit_work(struct io_wq_work * work)6237 static void io_wq_submit_work(struct io_wq_work *work)
6238 {
6239 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
6240 	struct io_kiocb *timeout;
6241 	int ret = 0;
6242 
6243 	timeout = io_prep_linked_timeout(req);
6244 	if (timeout)
6245 		io_queue_linked_timeout(timeout);
6246 
6247 	if (work->flags & IO_WQ_WORK_CANCEL)
6248 		ret = -ECANCELED;
6249 
6250 	if (!ret) {
6251 		do {
6252 			ret = io_issue_sqe(req, 0);
6253 			/*
6254 			 * We can get EAGAIN for polled IO even though we're
6255 			 * forcing a sync submission from here, since we can't
6256 			 * wait for request slots on the block side.
6257 			 */
6258 			if (ret != -EAGAIN)
6259 				break;
6260 			cond_resched();
6261 		} while (1);
6262 	}
6263 
6264 	/* avoid locking problems by failing it from a clean context */
6265 	if (ret) {
6266 		/* io-wq is going to take one down */
6267 		req_ref_get(req);
6268 		io_req_task_queue_fail(req, ret);
6269 	}
6270 }
6271 
6272 #define FFS_ASYNC_READ		0x1UL
6273 #define FFS_ASYNC_WRITE		0x2UL
6274 #ifdef CONFIG_64BIT
6275 #define FFS_ISREG		0x4UL
6276 #else
6277 #define FFS_ISREG		0x0UL
6278 #endif
6279 #define FFS_MASK		~(FFS_ASYNC_READ|FFS_ASYNC_WRITE|FFS_ISREG)
6280 
io_fixed_file_slot(struct io_file_table * table,unsigned i)6281 static inline struct io_fixed_file *io_fixed_file_slot(struct io_file_table *table,
6282 						      unsigned i)
6283 {
6284 	struct io_fixed_file *table_l2;
6285 
6286 	table_l2 = table->files[i >> IORING_FILE_TABLE_SHIFT];
6287 	return &table_l2[i & IORING_FILE_TABLE_MASK];
6288 }
6289 
io_file_from_index(struct io_ring_ctx * ctx,int index)6290 static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
6291 					      int index)
6292 {
6293 	struct io_fixed_file *slot = io_fixed_file_slot(&ctx->file_table, index);
6294 
6295 	return (struct file *) (slot->file_ptr & FFS_MASK);
6296 }
6297 
io_fixed_file_set(struct io_fixed_file * file_slot,struct file * file)6298 static void io_fixed_file_set(struct io_fixed_file *file_slot, struct file *file)
6299 {
6300 	unsigned long file_ptr = (unsigned long) file;
6301 
6302 	if (__io_file_supports_async(file, READ))
6303 		file_ptr |= FFS_ASYNC_READ;
6304 	if (__io_file_supports_async(file, WRITE))
6305 		file_ptr |= FFS_ASYNC_WRITE;
6306 	if (S_ISREG(file_inode(file)->i_mode))
6307 		file_ptr |= FFS_ISREG;
6308 	file_slot->file_ptr = file_ptr;
6309 }
6310 
io_file_get(struct io_submit_state * state,struct io_kiocb * req,int fd,bool fixed)6311 static struct file *io_file_get(struct io_submit_state *state,
6312 				struct io_kiocb *req, int fd, bool fixed)
6313 {
6314 	struct io_ring_ctx *ctx = req->ctx;
6315 	struct file *file;
6316 
6317 	if (fixed) {
6318 		unsigned long file_ptr;
6319 
6320 		if (unlikely((unsigned int)fd >= ctx->nr_user_files))
6321 			return NULL;
6322 		fd = array_index_nospec(fd, ctx->nr_user_files);
6323 		file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr;
6324 		file = (struct file *) (file_ptr & FFS_MASK);
6325 		file_ptr &= ~FFS_MASK;
6326 		/* mask in overlapping REQ_F and FFS bits */
6327 		req->flags |= (file_ptr << REQ_F_ASYNC_READ_BIT);
6328 		io_req_set_rsrc_node(req);
6329 	} else {
6330 		trace_io_uring_file_get(ctx, fd);
6331 		file = __io_file_get(state, fd);
6332 
6333 		/* we don't allow fixed io_uring files */
6334 		if (file && unlikely(file->f_op == &io_uring_fops))
6335 			io_req_track_inflight(req);
6336 	}
6337 
6338 	return file;
6339 }
6340 
io_link_timeout_fn(struct hrtimer * timer)6341 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
6342 {
6343 	struct io_timeout_data *data = container_of(timer,
6344 						struct io_timeout_data, timer);
6345 	struct io_kiocb *prev, *req = data->req;
6346 	struct io_ring_ctx *ctx = req->ctx;
6347 	unsigned long flags;
6348 
6349 	spin_lock_irqsave(&ctx->completion_lock, flags);
6350 	prev = req->timeout.head;
6351 	req->timeout.head = NULL;
6352 
6353 	/*
6354 	 * We don't expect the list to be empty, that will only happen if we
6355 	 * race with the completion of the linked work.
6356 	 */
6357 	if (prev) {
6358 		io_remove_next_linked(prev);
6359 		if (!req_ref_inc_not_zero(prev))
6360 			prev = NULL;
6361 	}
6362 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
6363 
6364 	if (prev) {
6365 		io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
6366 		io_put_req_deferred(prev, 1);
6367 		io_put_req_deferred(req, 1);
6368 	} else {
6369 		io_req_complete_post(req, -ETIME, 0);
6370 	}
6371 	return HRTIMER_NORESTART;
6372 }
6373 
io_queue_linked_timeout(struct io_kiocb * req)6374 static void io_queue_linked_timeout(struct io_kiocb *req)
6375 {
6376 	struct io_ring_ctx *ctx = req->ctx;
6377 
6378 	spin_lock_irq(&ctx->completion_lock);
6379 	/*
6380 	 * If the back reference is NULL, then our linked request finished
6381 	 * before we got a chance to setup the timer
6382 	 */
6383 	if (req->timeout.head) {
6384 		struct io_timeout_data *data = req->async_data;
6385 
6386 		data->timer.function = io_link_timeout_fn;
6387 		hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
6388 				data->mode);
6389 	}
6390 	spin_unlock_irq(&ctx->completion_lock);
6391 	/* drop submission reference */
6392 	io_put_req(req);
6393 }
6394 
io_prep_linked_timeout(struct io_kiocb * req)6395 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
6396 {
6397 	struct io_kiocb *nxt = req->link;
6398 
6399 	if (!nxt || (req->flags & REQ_F_LINK_TIMEOUT) ||
6400 	    nxt->opcode != IORING_OP_LINK_TIMEOUT)
6401 		return NULL;
6402 
6403 	nxt->timeout.head = req;
6404 	nxt->flags |= REQ_F_LTIMEOUT_ACTIVE;
6405 	req->flags |= REQ_F_LINK_TIMEOUT;
6406 	return nxt;
6407 }
6408 
__io_queue_sqe(struct io_kiocb * req)6409 static void __io_queue_sqe(struct io_kiocb *req)
6410 {
6411 	struct io_kiocb *linked_timeout = io_prep_linked_timeout(req);
6412 	int ret;
6413 
6414 	ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
6415 
6416 	/*
6417 	 * We async punt it if the file wasn't marked NOWAIT, or if the file
6418 	 * doesn't support non-blocking read/write attempts
6419 	 */
6420 	if (likely(!ret)) {
6421 		/* drop submission reference */
6422 		if (req->flags & REQ_F_COMPLETE_INLINE) {
6423 			struct io_ring_ctx *ctx = req->ctx;
6424 			struct io_comp_state *cs = &ctx->submit_state.comp;
6425 
6426 			cs->reqs[cs->nr++] = req;
6427 			if (cs->nr == ARRAY_SIZE(cs->reqs))
6428 				io_submit_flush_completions(cs, ctx);
6429 		} else {
6430 			io_put_req(req);
6431 		}
6432 	} else if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
6433 		if (!io_arm_poll_handler(req)) {
6434 			/*
6435 			 * Queued up for async execution, worker will release
6436 			 * submit reference when the iocb is actually submitted.
6437 			 */
6438 			io_queue_async_work(req);
6439 		}
6440 	} else {
6441 		io_req_complete_failed(req, ret);
6442 	}
6443 	if (linked_timeout)
6444 		io_queue_linked_timeout(linked_timeout);
6445 }
6446 
io_queue_sqe(struct io_kiocb * req)6447 static void io_queue_sqe(struct io_kiocb *req)
6448 {
6449 	int ret;
6450 
6451 	ret = io_req_defer(req);
6452 	if (ret) {
6453 		if (ret != -EIOCBQUEUED) {
6454 fail_req:
6455 			io_req_complete_failed(req, ret);
6456 		}
6457 	} else if (req->flags & REQ_F_FORCE_ASYNC) {
6458 		ret = io_req_prep_async(req);
6459 		if (unlikely(ret))
6460 			goto fail_req;
6461 		io_queue_async_work(req);
6462 	} else {
6463 		__io_queue_sqe(req);
6464 	}
6465 }
6466 
6467 /*
6468  * Check SQE restrictions (opcode and flags).
6469  *
6470  * Returns 'true' if SQE is allowed, 'false' otherwise.
6471  */
io_check_restriction(struct io_ring_ctx * ctx,struct io_kiocb * req,unsigned int sqe_flags)6472 static inline bool io_check_restriction(struct io_ring_ctx *ctx,
6473 					struct io_kiocb *req,
6474 					unsigned int sqe_flags)
6475 {
6476 	if (!ctx->restricted)
6477 		return true;
6478 
6479 	if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
6480 		return false;
6481 
6482 	if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
6483 	    ctx->restrictions.sqe_flags_required)
6484 		return false;
6485 
6486 	if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
6487 			  ctx->restrictions.sqe_flags_required))
6488 		return false;
6489 
6490 	return true;
6491 }
6492 
io_init_req(struct io_ring_ctx * ctx,struct io_kiocb * req,const struct io_uring_sqe * sqe)6493 static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
6494 		       const struct io_uring_sqe *sqe)
6495 {
6496 	struct io_submit_state *state;
6497 	unsigned int sqe_flags;
6498 	int personality, ret = 0;
6499 
6500 	req->opcode = READ_ONCE(sqe->opcode);
6501 	/* same numerical values with corresponding REQ_F_*, safe to copy */
6502 	req->flags = sqe_flags = READ_ONCE(sqe->flags);
6503 	req->user_data = READ_ONCE(sqe->user_data);
6504 	req->async_data = NULL;
6505 	req->file = NULL;
6506 	req->ctx = ctx;
6507 	req->link = NULL;
6508 	req->fixed_rsrc_refs = NULL;
6509 	/* one is dropped after submission, the other at completion */
6510 	atomic_set(&req->refs, 2);
6511 	req->task = current;
6512 	req->result = 0;
6513 	req->work.creds = NULL;
6514 
6515 	/* enforce forwards compatibility on users */
6516 	if (unlikely(sqe_flags & ~SQE_VALID_FLAGS))
6517 		return -EINVAL;
6518 	if (unlikely(req->opcode >= IORING_OP_LAST))
6519 		return -EINVAL;
6520 	if (unlikely(!io_check_restriction(ctx, req, sqe_flags)))
6521 		return -EACCES;
6522 
6523 	if ((sqe_flags & IOSQE_BUFFER_SELECT) &&
6524 	    !io_op_defs[req->opcode].buffer_select)
6525 		return -EOPNOTSUPP;
6526 
6527 	personality = READ_ONCE(sqe->personality);
6528 	if (personality) {
6529 		req->work.creds = xa_load(&ctx->personalities, personality);
6530 		if (!req->work.creds)
6531 			return -EINVAL;
6532 		get_cred(req->work.creds);
6533 	}
6534 	state = &ctx->submit_state;
6535 
6536 	/*
6537 	 * Plug now if we have more than 1 IO left after this, and the target
6538 	 * is potentially a read/write to block based storage.
6539 	 */
6540 	if (!state->plug_started && state->ios_left > 1 &&
6541 	    io_op_defs[req->opcode].plug) {
6542 		blk_start_plug(&state->plug);
6543 		state->plug_started = true;
6544 	}
6545 
6546 	if (io_op_defs[req->opcode].needs_file) {
6547 		bool fixed = req->flags & REQ_F_FIXED_FILE;
6548 
6549 		req->file = io_file_get(state, req, READ_ONCE(sqe->fd), fixed);
6550 		if (unlikely(!req->file))
6551 			ret = -EBADF;
6552 	}
6553 
6554 	state->ios_left--;
6555 	return ret;
6556 }
6557 
io_submit_sqe(struct io_ring_ctx * ctx,struct io_kiocb * req,const struct io_uring_sqe * sqe)6558 static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
6559 			 const struct io_uring_sqe *sqe)
6560 {
6561 	struct io_submit_link *link = &ctx->submit_state.link;
6562 	int ret;
6563 
6564 	ret = io_init_req(ctx, req, sqe);
6565 	if (unlikely(ret)) {
6566 fail_req:
6567 		if (link->head) {
6568 			/* fail even hard links since we don't submit */
6569 			link->head->flags |= REQ_F_FAIL_LINK;
6570 			io_req_complete_failed(link->head, -ECANCELED);
6571 			link->head = NULL;
6572 		}
6573 		io_req_complete_failed(req, ret);
6574 		return ret;
6575 	}
6576 	ret = io_req_prep(req, sqe);
6577 	if (unlikely(ret))
6578 		goto fail_req;
6579 
6580 	/* don't need @sqe from now on */
6581 	trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data,
6582 				true, ctx->flags & IORING_SETUP_SQPOLL);
6583 
6584 	/*
6585 	 * If we already have a head request, queue this one for async
6586 	 * submittal once the head completes. If we don't have a head but
6587 	 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
6588 	 * submitted sync once the chain is complete. If none of those
6589 	 * conditions are true (normal request), then just queue it.
6590 	 */
6591 	if (link->head) {
6592 		struct io_kiocb *head = link->head;
6593 
6594 		/*
6595 		 * Taking sequential execution of a link, draining both sides
6596 		 * of the link also fullfils IOSQE_IO_DRAIN semantics for all
6597 		 * requests in the link. So, it drains the head and the
6598 		 * next after the link request. The last one is done via
6599 		 * drain_next flag to persist the effect across calls.
6600 		 */
6601 		if (req->flags & REQ_F_IO_DRAIN) {
6602 			head->flags |= REQ_F_IO_DRAIN;
6603 			ctx->drain_next = 1;
6604 		}
6605 		ret = io_req_prep_async(req);
6606 		if (unlikely(ret))
6607 			goto fail_req;
6608 		trace_io_uring_link(ctx, req, head);
6609 		link->last->link = req;
6610 		link->last = req;
6611 
6612 		/* last request of a link, enqueue the link */
6613 		if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) {
6614 			io_queue_sqe(head);
6615 			link->head = NULL;
6616 		}
6617 	} else {
6618 		if (unlikely(ctx->drain_next)) {
6619 			req->flags |= REQ_F_IO_DRAIN;
6620 			ctx->drain_next = 0;
6621 		}
6622 		if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) {
6623 			link->head = req;
6624 			link->last = req;
6625 		} else {
6626 			io_queue_sqe(req);
6627 		}
6628 	}
6629 
6630 	return 0;
6631 }
6632 
6633 /*
6634  * Batched submission is done, ensure local IO is flushed out.
6635  */
io_submit_state_end(struct io_submit_state * state,struct io_ring_ctx * ctx)6636 static void io_submit_state_end(struct io_submit_state *state,
6637 				struct io_ring_ctx *ctx)
6638 {
6639 	if (state->link.head)
6640 		io_queue_sqe(state->link.head);
6641 	if (state->comp.nr)
6642 		io_submit_flush_completions(&state->comp, ctx);
6643 	if (state->plug_started)
6644 		blk_finish_plug(&state->plug);
6645 	io_state_file_put(state);
6646 }
6647 
6648 /*
6649  * Start submission side cache.
6650  */
io_submit_state_start(struct io_submit_state * state,unsigned int max_ios)6651 static void io_submit_state_start(struct io_submit_state *state,
6652 				  unsigned int max_ios)
6653 {
6654 	state->plug_started = false;
6655 	state->ios_left = max_ios;
6656 	/* set only head, no need to init link_last in advance */
6657 	state->link.head = NULL;
6658 }
6659 
io_commit_sqring(struct io_ring_ctx * ctx)6660 static void io_commit_sqring(struct io_ring_ctx *ctx)
6661 {
6662 	struct io_rings *rings = ctx->rings;
6663 
6664 	/*
6665 	 * Ensure any loads from the SQEs are done at this point,
6666 	 * since once we write the new head, the application could
6667 	 * write new data to them.
6668 	 */
6669 	smp_store_release(&rings->sq.head, ctx->cached_sq_head);
6670 }
6671 
6672 /*
6673  * Fetch an sqe, if one is available. Note that sqe_ptr will point to memory
6674  * that is mapped by userspace. This means that care needs to be taken to
6675  * ensure that reads are stable, as we cannot rely on userspace always
6676  * being a good citizen. If members of the sqe are validated and then later
6677  * used, it's important that those reads are done through READ_ONCE() to
6678  * prevent a re-load down the line.
6679  */
io_get_sqe(struct io_ring_ctx * ctx)6680 static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
6681 {
6682 	u32 *sq_array = ctx->sq_array;
6683 	unsigned head;
6684 
6685 	/*
6686 	 * The cached sq head (or cq tail) serves two purposes:
6687 	 *
6688 	 * 1) allows us to batch the cost of updating the user visible
6689 	 *    head updates.
6690 	 * 2) allows the kernel side to track the head on its own, even
6691 	 *    though the application is the one updating it.
6692 	 */
6693 	head = READ_ONCE(sq_array[ctx->cached_sq_head++ & ctx->sq_mask]);
6694 	if (likely(head < ctx->sq_entries))
6695 		return &ctx->sq_sqes[head];
6696 
6697 	/* drop invalid entries */
6698 	ctx->cached_sq_dropped++;
6699 	WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
6700 	return NULL;
6701 }
6702 
io_submit_sqes(struct io_ring_ctx * ctx,unsigned int nr)6703 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
6704 {
6705 	int submitted = 0;
6706 
6707 	/* make sure SQ entry isn't read before tail */
6708 	nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx));
6709 
6710 	if (!percpu_ref_tryget_many(&ctx->refs, nr))
6711 		return -EAGAIN;
6712 
6713 	percpu_counter_add(&current->io_uring->inflight, nr);
6714 	refcount_add(nr, &current->usage);
6715 	io_submit_state_start(&ctx->submit_state, nr);
6716 
6717 	while (submitted < nr) {
6718 		const struct io_uring_sqe *sqe;
6719 		struct io_kiocb *req;
6720 
6721 		req = io_alloc_req(ctx);
6722 		if (unlikely(!req)) {
6723 			if (!submitted)
6724 				submitted = -EAGAIN;
6725 			break;
6726 		}
6727 		sqe = io_get_sqe(ctx);
6728 		if (unlikely(!sqe)) {
6729 			kmem_cache_free(req_cachep, req);
6730 			break;
6731 		}
6732 		/* will complete beyond this point, count as submitted */
6733 		submitted++;
6734 		if (io_submit_sqe(ctx, req, sqe))
6735 			break;
6736 	}
6737 
6738 	if (unlikely(submitted != nr)) {
6739 		int ref_used = (submitted == -EAGAIN) ? 0 : submitted;
6740 		struct io_uring_task *tctx = current->io_uring;
6741 		int unused = nr - ref_used;
6742 
6743 		percpu_ref_put_many(&ctx->refs, unused);
6744 		percpu_counter_sub(&tctx->inflight, unused);
6745 		put_task_struct_many(current, unused);
6746 	}
6747 
6748 	io_submit_state_end(&ctx->submit_state, ctx);
6749 	 /* Commit SQ ring head once we've consumed and submitted all SQEs */
6750 	io_commit_sqring(ctx);
6751 
6752 	return submitted;
6753 }
6754 
io_ring_set_wakeup_flag(struct io_ring_ctx * ctx)6755 static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx)
6756 {
6757 	/* Tell userspace we may need a wakeup call */
6758 	spin_lock_irq(&ctx->completion_lock);
6759 	ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
6760 	spin_unlock_irq(&ctx->completion_lock);
6761 }
6762 
io_ring_clear_wakeup_flag(struct io_ring_ctx * ctx)6763 static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx)
6764 {
6765 	spin_lock_irq(&ctx->completion_lock);
6766 	ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
6767 	spin_unlock_irq(&ctx->completion_lock);
6768 }
6769 
__io_sq_thread(struct io_ring_ctx * ctx,bool cap_entries)6770 static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
6771 {
6772 	unsigned int to_submit;
6773 	int ret = 0;
6774 
6775 	to_submit = io_sqring_entries(ctx);
6776 	/* if we're handling multiple rings, cap submit size for fairness */
6777 	if (cap_entries && to_submit > 8)
6778 		to_submit = 8;
6779 
6780 	if (!list_empty(&ctx->iopoll_list) || to_submit) {
6781 		unsigned nr_events = 0;
6782 
6783 		mutex_lock(&ctx->uring_lock);
6784 		if (!list_empty(&ctx->iopoll_list))
6785 			io_do_iopoll(ctx, &nr_events, 0);
6786 
6787 		/*
6788 		 * Don't submit if refs are dying, good for io_uring_register(),
6789 		 * but also it is relied upon by io_ring_exit_work()
6790 		 */
6791 		if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) &&
6792 		    !(ctx->flags & IORING_SETUP_R_DISABLED))
6793 			ret = io_submit_sqes(ctx, to_submit);
6794 		mutex_unlock(&ctx->uring_lock);
6795 	}
6796 
6797 	if (!io_sqring_full(ctx) && wq_has_sleeper(&ctx->sqo_sq_wait))
6798 		wake_up(&ctx->sqo_sq_wait);
6799 
6800 	return ret;
6801 }
6802 
io_sqd_update_thread_idle(struct io_sq_data * sqd)6803 static void io_sqd_update_thread_idle(struct io_sq_data *sqd)
6804 {
6805 	struct io_ring_ctx *ctx;
6806 	unsigned sq_thread_idle = 0;
6807 
6808 	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6809 		sq_thread_idle = max(sq_thread_idle, ctx->sq_thread_idle);
6810 	sqd->sq_thread_idle = sq_thread_idle;
6811 }
6812 
io_sq_thread(void * data)6813 static int io_sq_thread(void *data)
6814 {
6815 	struct io_sq_data *sqd = data;
6816 	struct io_ring_ctx *ctx;
6817 	unsigned long timeout = 0;
6818 	char buf[TASK_COMM_LEN];
6819 	DEFINE_WAIT(wait);
6820 
6821 	snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
6822 	set_task_comm(current, buf);
6823 
6824 	if (sqd->sq_cpu != -1)
6825 		set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
6826 	else
6827 		set_cpus_allowed_ptr(current, cpu_online_mask);
6828 	current->flags |= PF_NO_SETAFFINITY;
6829 
6830 	mutex_lock(&sqd->lock);
6831 	/* a user may had exited before the thread started */
6832 	io_run_task_work_head(&sqd->park_task_work);
6833 
6834 	while (!test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state)) {
6835 		int ret;
6836 		bool cap_entries, sqt_spin, needs_sched;
6837 
6838 		if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) ||
6839 		    signal_pending(current)) {
6840 			bool did_sig = false;
6841 
6842 			mutex_unlock(&sqd->lock);
6843 			if (signal_pending(current)) {
6844 				struct ksignal ksig;
6845 
6846 				did_sig = get_signal(&ksig);
6847 			}
6848 			cond_resched();
6849 			mutex_lock(&sqd->lock);
6850 			io_run_task_work();
6851 			io_run_task_work_head(&sqd->park_task_work);
6852 			if (did_sig)
6853 				break;
6854 			timeout = jiffies + sqd->sq_thread_idle;
6855 			continue;
6856 		}
6857 		sqt_spin = false;
6858 		cap_entries = !list_is_singular(&sqd->ctx_list);
6859 		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
6860 			const struct cred *creds = NULL;
6861 
6862 			if (ctx->sq_creds != current_cred())
6863 				creds = override_creds(ctx->sq_creds);
6864 			ret = __io_sq_thread(ctx, cap_entries);
6865 			if (creds)
6866 				revert_creds(creds);
6867 			if (!sqt_spin && (ret > 0 || !list_empty(&ctx->iopoll_list)))
6868 				sqt_spin = true;
6869 		}
6870 
6871 		if (sqt_spin || !time_after(jiffies, timeout)) {
6872 			io_run_task_work();
6873 			cond_resched();
6874 			if (sqt_spin)
6875 				timeout = jiffies + sqd->sq_thread_idle;
6876 			continue;
6877 		}
6878 
6879 		prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
6880 		if (!test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state)) {
6881 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6882 				io_ring_set_wakeup_flag(ctx);
6883 
6884 			needs_sched = true;
6885 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
6886 				if ((ctx->flags & IORING_SETUP_IOPOLL) &&
6887 				    !list_empty_careful(&ctx->iopoll_list)) {
6888 					needs_sched = false;
6889 					break;
6890 				}
6891 				if (io_sqring_entries(ctx)) {
6892 					needs_sched = false;
6893 					break;
6894 				}
6895 			}
6896 
6897 			if (needs_sched) {
6898 				mutex_unlock(&sqd->lock);
6899 				schedule();
6900 				mutex_lock(&sqd->lock);
6901 			}
6902 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6903 				io_ring_clear_wakeup_flag(ctx);
6904 		}
6905 
6906 		finish_wait(&sqd->wait, &wait);
6907 		io_run_task_work_head(&sqd->park_task_work);
6908 		timeout = jiffies + sqd->sq_thread_idle;
6909 	}
6910 
6911 	io_uring_cancel_sqpoll(sqd);
6912 	sqd->thread = NULL;
6913 	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6914 		io_ring_set_wakeup_flag(ctx);
6915 	io_run_task_work();
6916 	io_run_task_work_head(&sqd->park_task_work);
6917 	mutex_unlock(&sqd->lock);
6918 
6919 	complete(&sqd->exited);
6920 	do_exit(0);
6921 }
6922 
6923 struct io_wait_queue {
6924 	struct wait_queue_entry wq;
6925 	struct io_ring_ctx *ctx;
6926 	unsigned to_wait;
6927 	unsigned nr_timeouts;
6928 };
6929 
io_should_wake(struct io_wait_queue * iowq)6930 static inline bool io_should_wake(struct io_wait_queue *iowq)
6931 {
6932 	struct io_ring_ctx *ctx = iowq->ctx;
6933 
6934 	/*
6935 	 * Wake up if we have enough events, or if a timeout occurred since we
6936 	 * started waiting. For timeouts, we always want to return to userspace,
6937 	 * regardless of event count.
6938 	 */
6939 	return io_cqring_events(ctx) >= iowq->to_wait ||
6940 			atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
6941 }
6942 
io_wake_function(struct wait_queue_entry * curr,unsigned int mode,int wake_flags,void * key)6943 static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
6944 			    int wake_flags, void *key)
6945 {
6946 	struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
6947 							wq);
6948 
6949 	/*
6950 	 * Cannot safely flush overflowed CQEs from here, ensure we wake up
6951 	 * the task, and the next invocation will do it.
6952 	 */
6953 	if (io_should_wake(iowq) || test_bit(0, &iowq->ctx->cq_check_overflow))
6954 		return autoremove_wake_function(curr, mode, wake_flags, key);
6955 	return -1;
6956 }
6957 
io_run_task_work_sig(void)6958 static int io_run_task_work_sig(void)
6959 {
6960 	if (io_run_task_work())
6961 		return 1;
6962 	if (!signal_pending(current))
6963 		return 0;
6964 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
6965 		return -ERESTARTSYS;
6966 	return -EINTR;
6967 }
6968 
6969 /* when returns >0, the caller should retry */
io_cqring_wait_schedule(struct io_ring_ctx * ctx,struct io_wait_queue * iowq,signed long * timeout)6970 static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
6971 					  struct io_wait_queue *iowq,
6972 					  signed long *timeout)
6973 {
6974 	int ret;
6975 
6976 	/* make sure we run task_work before checking for signals */
6977 	ret = io_run_task_work_sig();
6978 	if (ret || io_should_wake(iowq))
6979 		return ret;
6980 	/* let the caller flush overflows, retry */
6981 	if (test_bit(0, &ctx->cq_check_overflow))
6982 		return 1;
6983 
6984 	*timeout = schedule_timeout(*timeout);
6985 	return !*timeout ? -ETIME : 1;
6986 }
6987 
6988 /*
6989  * Wait until events become available, if we don't already have some. The
6990  * application must reap them itself, as they reside on the shared cq ring.
6991  */
io_cqring_wait(struct io_ring_ctx * ctx,int min_events,const sigset_t __user * sig,size_t sigsz,struct __kernel_timespec __user * uts)6992 static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
6993 			  const sigset_t __user *sig, size_t sigsz,
6994 			  struct __kernel_timespec __user *uts)
6995 {
6996 	struct io_wait_queue iowq = {
6997 		.wq = {
6998 			.private	= current,
6999 			.func		= io_wake_function,
7000 			.entry		= LIST_HEAD_INIT(iowq.wq.entry),
7001 		},
7002 		.ctx		= ctx,
7003 		.to_wait	= min_events,
7004 	};
7005 	struct io_rings *rings = ctx->rings;
7006 	signed long timeout = MAX_SCHEDULE_TIMEOUT;
7007 	int ret;
7008 
7009 	do {
7010 		io_cqring_overflow_flush(ctx, false);
7011 		if (io_cqring_events(ctx) >= min_events)
7012 			return 0;
7013 		if (!io_run_task_work())
7014 			break;
7015 	} while (1);
7016 
7017 	if (sig) {
7018 #ifdef CONFIG_COMPAT
7019 		if (in_compat_syscall())
7020 			ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
7021 						      sigsz);
7022 		else
7023 #endif
7024 			ret = set_user_sigmask(sig, sigsz);
7025 
7026 		if (ret)
7027 			return ret;
7028 	}
7029 
7030 	if (uts) {
7031 		struct timespec64 ts;
7032 
7033 		if (get_timespec64(&ts, uts))
7034 			return -EFAULT;
7035 		timeout = timespec64_to_jiffies(&ts);
7036 	}
7037 
7038 	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
7039 	trace_io_uring_cqring_wait(ctx, min_events);
7040 	do {
7041 		/* if we can't even flush overflow, don't wait for more */
7042 		if (!io_cqring_overflow_flush(ctx, false)) {
7043 			ret = -EBUSY;
7044 			break;
7045 		}
7046 		prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
7047 						TASK_INTERRUPTIBLE);
7048 		ret = io_cqring_wait_schedule(ctx, &iowq, &timeout);
7049 		finish_wait(&ctx->wait, &iowq.wq);
7050 		cond_resched();
7051 	} while (ret > 0);
7052 
7053 	restore_saved_sigmask_unless(ret == -EINTR);
7054 
7055 	return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
7056 }
7057 
io_free_file_tables(struct io_file_table * table,unsigned nr_files)7058 static void io_free_file_tables(struct io_file_table *table, unsigned nr_files)
7059 {
7060 	unsigned i, nr_tables = DIV_ROUND_UP(nr_files, IORING_MAX_FILES_TABLE);
7061 
7062 	for (i = 0; i < nr_tables; i++)
7063 		kfree(table->files[i]);
7064 	kfree(table->files);
7065 	table->files = NULL;
7066 }
7067 
io_rsrc_ref_lock(struct io_ring_ctx * ctx)7068 static inline void io_rsrc_ref_lock(struct io_ring_ctx *ctx)
7069 {
7070 	spin_lock_bh(&ctx->rsrc_ref_lock);
7071 }
7072 
io_rsrc_ref_unlock(struct io_ring_ctx * ctx)7073 static inline void io_rsrc_ref_unlock(struct io_ring_ctx *ctx)
7074 {
7075 	spin_unlock_bh(&ctx->rsrc_ref_lock);
7076 }
7077 
io_rsrc_node_destroy(struct io_rsrc_node * ref_node)7078 static void io_rsrc_node_destroy(struct io_rsrc_node *ref_node)
7079 {
7080 	percpu_ref_exit(&ref_node->refs);
7081 	kfree(ref_node);
7082 }
7083 
io_rsrc_node_switch(struct io_ring_ctx * ctx,struct io_rsrc_data * data_to_kill)7084 static void io_rsrc_node_switch(struct io_ring_ctx *ctx,
7085 				struct io_rsrc_data *data_to_kill)
7086 {
7087 	WARN_ON_ONCE(!ctx->rsrc_backup_node);
7088 	WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node);
7089 
7090 	if (data_to_kill) {
7091 		struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
7092 
7093 		rsrc_node->rsrc_data = data_to_kill;
7094 		io_rsrc_ref_lock(ctx);
7095 		list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
7096 		io_rsrc_ref_unlock(ctx);
7097 
7098 		atomic_inc(&data_to_kill->refs);
7099 		percpu_ref_kill(&rsrc_node->refs);
7100 		ctx->rsrc_node = NULL;
7101 	}
7102 
7103 	if (!ctx->rsrc_node) {
7104 		ctx->rsrc_node = ctx->rsrc_backup_node;
7105 		ctx->rsrc_backup_node = NULL;
7106 	}
7107 }
7108 
io_rsrc_node_switch_start(struct io_ring_ctx * ctx)7109 static int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
7110 {
7111 	if (ctx->rsrc_backup_node)
7112 		return 0;
7113 	ctx->rsrc_backup_node = io_rsrc_node_alloc(ctx);
7114 	return ctx->rsrc_backup_node ? 0 : -ENOMEM;
7115 }
7116 
io_rsrc_ref_quiesce(struct io_rsrc_data * data,struct io_ring_ctx * ctx)7117 static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, struct io_ring_ctx *ctx)
7118 {
7119 	int ret;
7120 
7121 	/* As we may drop ->uring_lock, other task may have started quiesce */
7122 	if (data->quiesce)
7123 		return -ENXIO;
7124 
7125 	data->quiesce = true;
7126 	do {
7127 		ret = io_rsrc_node_switch_start(ctx);
7128 		if (ret)
7129 			break;
7130 		io_rsrc_node_switch(ctx, data);
7131 
7132 		/* kill initial ref, already quiesced if zero */
7133 		if (atomic_dec_and_test(&data->refs))
7134 			break;
7135 		flush_delayed_work(&ctx->rsrc_put_work);
7136 		ret = wait_for_completion_interruptible(&data->done);
7137 		if (!ret)
7138 			break;
7139 
7140 		atomic_inc(&data->refs);
7141 		/* wait for all works potentially completing data->done */
7142 		flush_delayed_work(&ctx->rsrc_put_work);
7143 		reinit_completion(&data->done);
7144 
7145 		mutex_unlock(&ctx->uring_lock);
7146 		ret = io_run_task_work_sig();
7147 		mutex_lock(&ctx->uring_lock);
7148 	} while (ret >= 0);
7149 	data->quiesce = false;
7150 
7151 	return ret;
7152 }
7153 
io_rsrc_data_free(struct io_rsrc_data * data)7154 static void io_rsrc_data_free(struct io_rsrc_data *data)
7155 {
7156 	kvfree(data->tags);
7157 	kfree(data);
7158 }
7159 
io_rsrc_data_alloc(struct io_ring_ctx * ctx,rsrc_put_fn * do_put,unsigned nr)7160 static struct io_rsrc_data *io_rsrc_data_alloc(struct io_ring_ctx *ctx,
7161 					       rsrc_put_fn *do_put,
7162 					       unsigned nr)
7163 {
7164 	struct io_rsrc_data *data;
7165 
7166 	data = kzalloc(sizeof(*data), GFP_KERNEL);
7167 	if (!data)
7168 		return NULL;
7169 
7170 	data->tags = kvcalloc(nr, sizeof(*data->tags), GFP_KERNEL);
7171 	if (!data->tags) {
7172 		kfree(data);
7173 		return NULL;
7174 	}
7175 
7176 	atomic_set(&data->refs, 1);
7177 	data->ctx = ctx;
7178 	data->do_put = do_put;
7179 	init_completion(&data->done);
7180 	return data;
7181 }
7182 
__io_sqe_files_unregister(struct io_ring_ctx * ctx)7183 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
7184 {
7185 #if defined(CONFIG_UNIX)
7186 	if (ctx->ring_sock) {
7187 		struct sock *sock = ctx->ring_sock->sk;
7188 		struct sk_buff *skb;
7189 
7190 		while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
7191 			kfree_skb(skb);
7192 	}
7193 #else
7194 	int i;
7195 
7196 	for (i = 0; i < ctx->nr_user_files; i++) {
7197 		struct file *file;
7198 
7199 		file = io_file_from_index(ctx, i);
7200 		if (file)
7201 			fput(file);
7202 	}
7203 #endif
7204 	io_free_file_tables(&ctx->file_table, ctx->nr_user_files);
7205 	io_rsrc_data_free(ctx->file_data);
7206 	ctx->file_data = NULL;
7207 	ctx->nr_user_files = 0;
7208 }
7209 
io_sqe_files_unregister(struct io_ring_ctx * ctx)7210 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
7211 {
7212 	int ret;
7213 
7214 	if (!ctx->file_data)
7215 		return -ENXIO;
7216 	ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
7217 	if (!ret)
7218 		__io_sqe_files_unregister(ctx);
7219 	return ret;
7220 }
7221 
io_sq_thread_unpark(struct io_sq_data * sqd)7222 static void io_sq_thread_unpark(struct io_sq_data *sqd)
7223 	__releases(&sqd->lock)
7224 {
7225 	WARN_ON_ONCE(sqd->thread == current);
7226 
7227 	/*
7228 	 * Do the dance but not conditional clear_bit() because it'd race with
7229 	 * other threads incrementing park_pending and setting the bit.
7230 	 */
7231 	clear_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
7232 	if (atomic_dec_return(&sqd->park_pending))
7233 		set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
7234 	mutex_unlock(&sqd->lock);
7235 }
7236 
io_sq_thread_park(struct io_sq_data * sqd)7237 static void io_sq_thread_park(struct io_sq_data *sqd)
7238 	__acquires(&sqd->lock)
7239 {
7240 	WARN_ON_ONCE(sqd->thread == current);
7241 
7242 	atomic_inc(&sqd->park_pending);
7243 	set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
7244 	mutex_lock(&sqd->lock);
7245 	if (sqd->thread)
7246 		wake_up_process(sqd->thread);
7247 }
7248 
io_sq_thread_stop(struct io_sq_data * sqd)7249 static void io_sq_thread_stop(struct io_sq_data *sqd)
7250 {
7251 	WARN_ON_ONCE(sqd->thread == current);
7252 	WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state));
7253 
7254 	set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
7255 	mutex_lock(&sqd->lock);
7256 	if (sqd->thread)
7257 		wake_up_process(sqd->thread);
7258 	mutex_unlock(&sqd->lock);
7259 	wait_for_completion(&sqd->exited);
7260 }
7261 
io_put_sq_data(struct io_sq_data * sqd)7262 static void io_put_sq_data(struct io_sq_data *sqd)
7263 {
7264 	if (refcount_dec_and_test(&sqd->refs)) {
7265 		WARN_ON_ONCE(atomic_read(&sqd->park_pending));
7266 
7267 		io_sq_thread_stop(sqd);
7268 		kfree(sqd);
7269 	}
7270 }
7271 
io_sq_thread_finish(struct io_ring_ctx * ctx)7272 static void io_sq_thread_finish(struct io_ring_ctx *ctx)
7273 {
7274 	struct io_sq_data *sqd = ctx->sq_data;
7275 
7276 	if (sqd) {
7277 		io_sq_thread_park(sqd);
7278 		list_del_init(&ctx->sqd_list);
7279 		io_sqd_update_thread_idle(sqd);
7280 		io_sq_thread_unpark(sqd);
7281 
7282 		io_put_sq_data(sqd);
7283 		ctx->sq_data = NULL;
7284 	}
7285 }
7286 
io_attach_sq_data(struct io_uring_params * p)7287 static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
7288 {
7289 	struct io_ring_ctx *ctx_attach;
7290 	struct io_sq_data *sqd;
7291 	struct fd f;
7292 
7293 	f = fdget(p->wq_fd);
7294 	if (!f.file)
7295 		return ERR_PTR(-ENXIO);
7296 	if (f.file->f_op != &io_uring_fops) {
7297 		fdput(f);
7298 		return ERR_PTR(-EINVAL);
7299 	}
7300 
7301 	ctx_attach = f.file->private_data;
7302 	sqd = ctx_attach->sq_data;
7303 	if (!sqd) {
7304 		fdput(f);
7305 		return ERR_PTR(-EINVAL);
7306 	}
7307 	if (sqd->task_tgid != current->tgid) {
7308 		fdput(f);
7309 		return ERR_PTR(-EPERM);
7310 	}
7311 
7312 	refcount_inc(&sqd->refs);
7313 	fdput(f);
7314 	return sqd;
7315 }
7316 
io_get_sq_data(struct io_uring_params * p,bool * attached)7317 static struct io_sq_data *io_get_sq_data(struct io_uring_params *p,
7318 					 bool *attached)
7319 {
7320 	struct io_sq_data *sqd;
7321 
7322 	*attached = false;
7323 	if (p->flags & IORING_SETUP_ATTACH_WQ) {
7324 		sqd = io_attach_sq_data(p);
7325 		if (!IS_ERR(sqd)) {
7326 			*attached = true;
7327 			return sqd;
7328 		}
7329 		/* fall through for EPERM case, setup new sqd/task */
7330 		if (PTR_ERR(sqd) != -EPERM)
7331 			return sqd;
7332 	}
7333 
7334 	sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
7335 	if (!sqd)
7336 		return ERR_PTR(-ENOMEM);
7337 
7338 	atomic_set(&sqd->park_pending, 0);
7339 	refcount_set(&sqd->refs, 1);
7340 	INIT_LIST_HEAD(&sqd->ctx_list);
7341 	mutex_init(&sqd->lock);
7342 	init_waitqueue_head(&sqd->wait);
7343 	init_completion(&sqd->exited);
7344 	return sqd;
7345 }
7346 
7347 #if defined(CONFIG_UNIX)
7348 /*
7349  * Ensure the UNIX gc is aware of our file set, so we are certain that
7350  * the io_uring can be safely unregistered on process exit, even if we have
7351  * loops in the file referencing.
7352  */
__io_sqe_files_scm(struct io_ring_ctx * ctx,int nr,int offset)7353 static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
7354 {
7355 	struct sock *sk = ctx->ring_sock->sk;
7356 	struct scm_fp_list *fpl;
7357 	struct sk_buff *skb;
7358 	int i, nr_files;
7359 
7360 	fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
7361 	if (!fpl)
7362 		return -ENOMEM;
7363 
7364 	skb = alloc_skb(0, GFP_KERNEL);
7365 	if (!skb) {
7366 		kfree(fpl);
7367 		return -ENOMEM;
7368 	}
7369 
7370 	skb->sk = sk;
7371 
7372 	nr_files = 0;
7373 	fpl->user = get_uid(current_user());
7374 	for (i = 0; i < nr; i++) {
7375 		struct file *file = io_file_from_index(ctx, i + offset);
7376 
7377 		if (!file)
7378 			continue;
7379 		fpl->fp[nr_files] = get_file(file);
7380 		unix_inflight(fpl->user, fpl->fp[nr_files]);
7381 		nr_files++;
7382 	}
7383 
7384 	if (nr_files) {
7385 		fpl->max = SCM_MAX_FD;
7386 		fpl->count = nr_files;
7387 		UNIXCB(skb).fp = fpl;
7388 		skb->destructor = unix_destruct_scm;
7389 		refcount_add(skb->truesize, &sk->sk_wmem_alloc);
7390 		skb_queue_head(&sk->sk_receive_queue, skb);
7391 
7392 		for (i = 0; i < nr_files; i++)
7393 			fput(fpl->fp[i]);
7394 	} else {
7395 		kfree_skb(skb);
7396 		kfree(fpl);
7397 	}
7398 
7399 	return 0;
7400 }
7401 
7402 /*
7403  * If UNIX sockets are enabled, fd passing can cause a reference cycle which
7404  * causes regular reference counting to break down. We rely on the UNIX
7405  * garbage collection to take care of this problem for us.
7406  */
io_sqe_files_scm(struct io_ring_ctx * ctx)7407 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
7408 {
7409 	unsigned left, total;
7410 	int ret = 0;
7411 
7412 	total = 0;
7413 	left = ctx->nr_user_files;
7414 	while (left) {
7415 		unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
7416 
7417 		ret = __io_sqe_files_scm(ctx, this_files, total);
7418 		if (ret)
7419 			break;
7420 		left -= this_files;
7421 		total += this_files;
7422 	}
7423 
7424 	if (!ret)
7425 		return 0;
7426 
7427 	while (total < ctx->nr_user_files) {
7428 		struct file *file = io_file_from_index(ctx, total);
7429 
7430 		if (file)
7431 			fput(file);
7432 		total++;
7433 	}
7434 
7435 	return ret;
7436 }
7437 #else
io_sqe_files_scm(struct io_ring_ctx * ctx)7438 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
7439 {
7440 	return 0;
7441 }
7442 #endif
7443 
io_alloc_file_tables(struct io_file_table * table,unsigned nr_files)7444 static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
7445 {
7446 	unsigned i, nr_tables = DIV_ROUND_UP(nr_files, IORING_MAX_FILES_TABLE);
7447 
7448 	table->files = kcalloc(nr_tables, sizeof(*table->files), GFP_KERNEL);
7449 	if (!table->files)
7450 		return false;
7451 
7452 	for (i = 0; i < nr_tables; i++) {
7453 		unsigned int this_files = min(nr_files, IORING_MAX_FILES_TABLE);
7454 
7455 		table->files[i] = kcalloc(this_files, sizeof(*table->files[i]),
7456 					GFP_KERNEL);
7457 		if (!table->files[i])
7458 			break;
7459 		nr_files -= this_files;
7460 	}
7461 
7462 	if (i == nr_tables)
7463 		return true;
7464 
7465 	io_free_file_tables(table, nr_tables * IORING_MAX_FILES_TABLE);
7466 	return false;
7467 }
7468 
io_rsrc_file_put(struct io_ring_ctx * ctx,struct io_rsrc_put * prsrc)7469 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
7470 {
7471 	struct file *file = prsrc->file;
7472 #if defined(CONFIG_UNIX)
7473 	struct sock *sock = ctx->ring_sock->sk;
7474 	struct sk_buff_head list, *head = &sock->sk_receive_queue;
7475 	struct sk_buff *skb;
7476 	int i;
7477 
7478 	__skb_queue_head_init(&list);
7479 
7480 	/*
7481 	 * Find the skb that holds this file in its SCM_RIGHTS. When found,
7482 	 * remove this entry and rearrange the file array.
7483 	 */
7484 	skb = skb_dequeue(head);
7485 	while (skb) {
7486 		struct scm_fp_list *fp;
7487 
7488 		fp = UNIXCB(skb).fp;
7489 		for (i = 0; i < fp->count; i++) {
7490 			int left;
7491 
7492 			if (fp->fp[i] != file)
7493 				continue;
7494 
7495 			unix_notinflight(fp->user, fp->fp[i]);
7496 			left = fp->count - 1 - i;
7497 			if (left) {
7498 				memmove(&fp->fp[i], &fp->fp[i + 1],
7499 						left * sizeof(struct file *));
7500 			}
7501 			fp->count--;
7502 			if (!fp->count) {
7503 				kfree_skb(skb);
7504 				skb = NULL;
7505 			} else {
7506 				__skb_queue_tail(&list, skb);
7507 			}
7508 			fput(file);
7509 			file = NULL;
7510 			break;
7511 		}
7512 
7513 		if (!file)
7514 			break;
7515 
7516 		__skb_queue_tail(&list, skb);
7517 
7518 		skb = skb_dequeue(head);
7519 	}
7520 
7521 	if (skb_peek(&list)) {
7522 		spin_lock_irq(&head->lock);
7523 		while ((skb = __skb_dequeue(&list)) != NULL)
7524 			__skb_queue_tail(head, skb);
7525 		spin_unlock_irq(&head->lock);
7526 	}
7527 #else
7528 	fput(file);
7529 #endif
7530 }
7531 
__io_rsrc_put_work(struct io_rsrc_node * ref_node)7532 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
7533 {
7534 	struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
7535 	struct io_ring_ctx *ctx = rsrc_data->ctx;
7536 	struct io_rsrc_put *prsrc, *tmp;
7537 
7538 	list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) {
7539 		list_del(&prsrc->list);
7540 
7541 		if (prsrc->tag) {
7542 			bool lock_ring = ctx->flags & IORING_SETUP_IOPOLL;
7543 			unsigned long flags;
7544 
7545 			io_ring_submit_lock(ctx, lock_ring);
7546 			spin_lock_irqsave(&ctx->completion_lock, flags);
7547 			io_cqring_fill_event(ctx, prsrc->tag, 0, 0);
7548 			ctx->cq_extra++;
7549 			io_commit_cqring(ctx);
7550 			spin_unlock_irqrestore(&ctx->completion_lock, flags);
7551 			io_cqring_ev_posted(ctx);
7552 			io_ring_submit_unlock(ctx, lock_ring);
7553 		}
7554 
7555 		rsrc_data->do_put(ctx, prsrc);
7556 		kfree(prsrc);
7557 	}
7558 
7559 	io_rsrc_node_destroy(ref_node);
7560 	if (atomic_dec_and_test(&rsrc_data->refs))
7561 		complete(&rsrc_data->done);
7562 }
7563 
io_rsrc_put_work(struct work_struct * work)7564 static void io_rsrc_put_work(struct work_struct *work)
7565 {
7566 	struct io_ring_ctx *ctx;
7567 	struct llist_node *node;
7568 
7569 	ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work);
7570 	node = llist_del_all(&ctx->rsrc_put_llist);
7571 
7572 	while (node) {
7573 		struct io_rsrc_node *ref_node;
7574 		struct llist_node *next = node->next;
7575 
7576 		ref_node = llist_entry(node, struct io_rsrc_node, llist);
7577 		__io_rsrc_put_work(ref_node);
7578 		node = next;
7579 	}
7580 }
7581 
io_rsrc_node_ref_zero(struct percpu_ref * ref)7582 static void io_rsrc_node_ref_zero(struct percpu_ref *ref)
7583 {
7584 	struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs);
7585 	struct io_ring_ctx *ctx = node->rsrc_data->ctx;
7586 	bool first_add = false;
7587 
7588 	io_rsrc_ref_lock(ctx);
7589 	node->done = true;
7590 
7591 	while (!list_empty(&ctx->rsrc_ref_list)) {
7592 		node = list_first_entry(&ctx->rsrc_ref_list,
7593 					    struct io_rsrc_node, node);
7594 		/* recycle ref nodes in order */
7595 		if (!node->done)
7596 			break;
7597 		list_del(&node->node);
7598 		first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist);
7599 	}
7600 	io_rsrc_ref_unlock(ctx);
7601 
7602 	if (first_add)
7603 		mod_delayed_work(system_wq, &ctx->rsrc_put_work, HZ);
7604 }
7605 
io_rsrc_node_alloc(struct io_ring_ctx * ctx)7606 static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
7607 {
7608 	struct io_rsrc_node *ref_node;
7609 
7610 	ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
7611 	if (!ref_node)
7612 		return NULL;
7613 
7614 	if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero,
7615 			    0, GFP_KERNEL)) {
7616 		kfree(ref_node);
7617 		return NULL;
7618 	}
7619 	INIT_LIST_HEAD(&ref_node->node);
7620 	INIT_LIST_HEAD(&ref_node->rsrc_list);
7621 	ref_node->done = false;
7622 	return ref_node;
7623 }
7624 
io_sqe_files_register(struct io_ring_ctx * ctx,void __user * arg,unsigned nr_args,u64 __user * tags)7625 static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
7626 				 unsigned nr_args, u64 __user *tags)
7627 {
7628 	__s32 __user *fds = (__s32 __user *) arg;
7629 	struct file *file;
7630 	int fd, ret;
7631 	unsigned i;
7632 	struct io_rsrc_data *file_data;
7633 
7634 	if (ctx->file_data)
7635 		return -EBUSY;
7636 	if (!nr_args)
7637 		return -EINVAL;
7638 	if (nr_args > IORING_MAX_FIXED_FILES)
7639 		return -EMFILE;
7640 	ret = io_rsrc_node_switch_start(ctx);
7641 	if (ret)
7642 		return ret;
7643 
7644 	file_data = io_rsrc_data_alloc(ctx, io_rsrc_file_put, nr_args);
7645 	if (!file_data)
7646 		return -ENOMEM;
7647 	ctx->file_data = file_data;
7648 	ret = -ENOMEM;
7649 	if (!io_alloc_file_tables(&ctx->file_table, nr_args))
7650 		goto out_free;
7651 
7652 	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
7653 		u64 tag = 0;
7654 
7655 		if ((tags && copy_from_user(&tag, &tags[i], sizeof(tag))) ||
7656 		    copy_from_user(&fd, &fds[i], sizeof(fd))) {
7657 			ret = -EFAULT;
7658 			goto out_fput;
7659 		}
7660 		/* allow sparse sets */
7661 		if (fd == -1) {
7662 			ret = -EINVAL;
7663 			if (unlikely(tag))
7664 				goto out_fput;
7665 			continue;
7666 		}
7667 
7668 		file = fget(fd);
7669 		ret = -EBADF;
7670 		if (unlikely(!file))
7671 			goto out_fput;
7672 
7673 		/*
7674 		 * Don't allow io_uring instances to be registered. If UNIX
7675 		 * isn't enabled, then this causes a reference cycle and this
7676 		 * instance can never get freed. If UNIX is enabled we'll
7677 		 * handle it just fine, but there's still no point in allowing
7678 		 * a ring fd as it doesn't support regular read/write anyway.
7679 		 */
7680 		if (file->f_op == &io_uring_fops) {
7681 			fput(file);
7682 			goto out_fput;
7683 		}
7684 		ctx->file_data->tags[i] = tag;
7685 		io_fixed_file_set(io_fixed_file_slot(&ctx->file_table, i), file);
7686 	}
7687 
7688 	ret = io_sqe_files_scm(ctx);
7689 	if (ret) {
7690 		__io_sqe_files_unregister(ctx);
7691 		return ret;
7692 	}
7693 
7694 	io_rsrc_node_switch(ctx, NULL);
7695 	return ret;
7696 out_fput:
7697 	for (i = 0; i < ctx->nr_user_files; i++) {
7698 		file = io_file_from_index(ctx, i);
7699 		if (file)
7700 			fput(file);
7701 	}
7702 	io_free_file_tables(&ctx->file_table, nr_args);
7703 	ctx->nr_user_files = 0;
7704 out_free:
7705 	io_rsrc_data_free(ctx->file_data);
7706 	ctx->file_data = NULL;
7707 	return ret;
7708 }
7709 
io_sqe_file_register(struct io_ring_ctx * ctx,struct file * file,int index)7710 static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
7711 				int index)
7712 {
7713 #if defined(CONFIG_UNIX)
7714 	struct sock *sock = ctx->ring_sock->sk;
7715 	struct sk_buff_head *head = &sock->sk_receive_queue;
7716 	struct sk_buff *skb;
7717 
7718 	/*
7719 	 * See if we can merge this file into an existing skb SCM_RIGHTS
7720 	 * file set. If there's no room, fall back to allocating a new skb
7721 	 * and filling it in.
7722 	 */
7723 	spin_lock_irq(&head->lock);
7724 	skb = skb_peek(head);
7725 	if (skb) {
7726 		struct scm_fp_list *fpl = UNIXCB(skb).fp;
7727 
7728 		if (fpl->count < SCM_MAX_FD) {
7729 			__skb_unlink(skb, head);
7730 			spin_unlock_irq(&head->lock);
7731 			fpl->fp[fpl->count] = get_file(file);
7732 			unix_inflight(fpl->user, fpl->fp[fpl->count]);
7733 			fpl->count++;
7734 			spin_lock_irq(&head->lock);
7735 			__skb_queue_head(head, skb);
7736 		} else {
7737 			skb = NULL;
7738 		}
7739 	}
7740 	spin_unlock_irq(&head->lock);
7741 
7742 	if (skb) {
7743 		fput(file);
7744 		return 0;
7745 	}
7746 
7747 	return __io_sqe_files_scm(ctx, 1, index);
7748 #else
7749 	return 0;
7750 #endif
7751 }
7752 
io_queue_rsrc_removal(struct io_rsrc_data * data,unsigned idx,struct io_rsrc_node * node,void * rsrc)7753 static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
7754 				 struct io_rsrc_node *node, void *rsrc)
7755 {
7756 	struct io_rsrc_put *prsrc;
7757 
7758 	prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
7759 	if (!prsrc)
7760 		return -ENOMEM;
7761 
7762 	prsrc->tag = data->tags[idx];
7763 	prsrc->rsrc = rsrc;
7764 	list_add(&prsrc->list, &node->rsrc_list);
7765 	return 0;
7766 }
7767 
__io_sqe_files_update(struct io_ring_ctx * ctx,struct io_uring_rsrc_update2 * up,unsigned nr_args)7768 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
7769 				 struct io_uring_rsrc_update2 *up,
7770 				 unsigned nr_args)
7771 {
7772 	u64 __user *tags = u64_to_user_ptr(up->tags);
7773 	__s32 __user *fds = u64_to_user_ptr(up->data);
7774 	struct io_rsrc_data *data = ctx->file_data;
7775 	struct io_fixed_file *file_slot;
7776 	struct file *file;
7777 	int fd, i, err = 0;
7778 	unsigned int done;
7779 	bool needs_switch = false;
7780 
7781 	if (!ctx->file_data)
7782 		return -ENXIO;
7783 	if (up->offset + nr_args > ctx->nr_user_files)
7784 		return -EINVAL;
7785 
7786 	for (done = 0; done < nr_args; done++) {
7787 		u64 tag = 0;
7788 
7789 		if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
7790 		    copy_from_user(&fd, &fds[done], sizeof(fd))) {
7791 			err = -EFAULT;
7792 			break;
7793 		}
7794 		if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
7795 			err = -EINVAL;
7796 			break;
7797 		}
7798 		if (fd == IORING_REGISTER_FILES_SKIP)
7799 			continue;
7800 
7801 		i = array_index_nospec(up->offset + done, ctx->nr_user_files);
7802 		file_slot = io_fixed_file_slot(&ctx->file_table, i);
7803 
7804 		if (file_slot->file_ptr) {
7805 			file = (struct file *)(file_slot->file_ptr & FFS_MASK);
7806 			err = io_queue_rsrc_removal(data, up->offset + done,
7807 						    ctx->rsrc_node, file);
7808 			if (err)
7809 				break;
7810 			file_slot->file_ptr = 0;
7811 			needs_switch = true;
7812 		}
7813 		if (fd != -1) {
7814 			file = fget(fd);
7815 			if (!file) {
7816 				err = -EBADF;
7817 				break;
7818 			}
7819 			/*
7820 			 * Don't allow io_uring instances to be registered. If
7821 			 * UNIX isn't enabled, then this causes a reference
7822 			 * cycle and this instance can never get freed. If UNIX
7823 			 * is enabled we'll handle it just fine, but there's
7824 			 * still no point in allowing a ring fd as it doesn't
7825 			 * support regular read/write anyway.
7826 			 */
7827 			if (file->f_op == &io_uring_fops) {
7828 				fput(file);
7829 				err = -EBADF;
7830 				break;
7831 			}
7832 			data->tags[up->offset + done] = tag;
7833 			io_fixed_file_set(file_slot, file);
7834 			err = io_sqe_file_register(ctx, file, i);
7835 			if (err) {
7836 				file_slot->file_ptr = 0;
7837 				fput(file);
7838 				break;
7839 			}
7840 		}
7841 	}
7842 
7843 	if (needs_switch)
7844 		io_rsrc_node_switch(ctx, data);
7845 	return done ? done : err;
7846 }
7847 
io_free_work(struct io_wq_work * work)7848 static struct io_wq_work *io_free_work(struct io_wq_work *work)
7849 {
7850 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
7851 
7852 	req = io_put_req_find_next(req);
7853 	return req ? &req->work : NULL;
7854 }
7855 
io_init_wq_offload(struct io_ring_ctx * ctx,struct task_struct * task)7856 static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx,
7857 					struct task_struct *task)
7858 {
7859 	struct io_wq_hash *hash;
7860 	struct io_wq_data data;
7861 	unsigned int concurrency;
7862 
7863 	hash = ctx->hash_map;
7864 	if (!hash) {
7865 		hash = kzalloc(sizeof(*hash), GFP_KERNEL);
7866 		if (!hash)
7867 			return ERR_PTR(-ENOMEM);
7868 		refcount_set(&hash->refs, 1);
7869 		init_waitqueue_head(&hash->wait);
7870 		ctx->hash_map = hash;
7871 	}
7872 
7873 	data.hash = hash;
7874 	data.task = task;
7875 	data.free_work = io_free_work;
7876 	data.do_work = io_wq_submit_work;
7877 
7878 	/* Do QD, or 4 * CPUS, whatever is smallest */
7879 	concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
7880 
7881 	return io_wq_create(concurrency, &data);
7882 }
7883 
io_uring_alloc_task_context(struct task_struct * task,struct io_ring_ctx * ctx)7884 static int io_uring_alloc_task_context(struct task_struct *task,
7885 				       struct io_ring_ctx *ctx)
7886 {
7887 	struct io_uring_task *tctx;
7888 	int ret;
7889 
7890 	tctx = kmalloc(sizeof(*tctx), GFP_KERNEL);
7891 	if (unlikely(!tctx))
7892 		return -ENOMEM;
7893 
7894 	ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
7895 	if (unlikely(ret)) {
7896 		kfree(tctx);
7897 		return ret;
7898 	}
7899 
7900 	tctx->io_wq = io_init_wq_offload(ctx, task);
7901 	if (IS_ERR(tctx->io_wq)) {
7902 		ret = PTR_ERR(tctx->io_wq);
7903 		percpu_counter_destroy(&tctx->inflight);
7904 		kfree(tctx);
7905 		return ret;
7906 	}
7907 
7908 	xa_init(&tctx->xa);
7909 	init_waitqueue_head(&tctx->wait);
7910 	tctx->last = NULL;
7911 	atomic_set(&tctx->in_idle, 0);
7912 	atomic_set(&tctx->inflight_tracked, 0);
7913 	task->io_uring = tctx;
7914 	spin_lock_init(&tctx->task_lock);
7915 	INIT_WQ_LIST(&tctx->task_list);
7916 	tctx->task_state = 0;
7917 	init_task_work(&tctx->task_work, tctx_task_work);
7918 	return 0;
7919 }
7920 
__io_uring_free(struct task_struct * tsk)7921 void __io_uring_free(struct task_struct *tsk)
7922 {
7923 	struct io_uring_task *tctx = tsk->io_uring;
7924 
7925 	WARN_ON_ONCE(!xa_empty(&tctx->xa));
7926 	WARN_ON_ONCE(tctx->io_wq);
7927 
7928 	percpu_counter_destroy(&tctx->inflight);
7929 	kfree(tctx);
7930 	tsk->io_uring = NULL;
7931 }
7932 
io_sq_offload_create(struct io_ring_ctx * ctx,struct io_uring_params * p)7933 static int io_sq_offload_create(struct io_ring_ctx *ctx,
7934 				struct io_uring_params *p)
7935 {
7936 	int ret;
7937 
7938 	/* Retain compatibility with failing for an invalid attach attempt */
7939 	if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) ==
7940 				IORING_SETUP_ATTACH_WQ) {
7941 		struct fd f;
7942 
7943 		f = fdget(p->wq_fd);
7944 		if (!f.file)
7945 			return -ENXIO;
7946 		fdput(f);
7947 		if (f.file->f_op != &io_uring_fops)
7948 			return -EINVAL;
7949 	}
7950 	if (ctx->flags & IORING_SETUP_SQPOLL) {
7951 		struct task_struct *tsk;
7952 		struct io_sq_data *sqd;
7953 		bool attached;
7954 
7955 		sqd = io_get_sq_data(p, &attached);
7956 		if (IS_ERR(sqd)) {
7957 			ret = PTR_ERR(sqd);
7958 			goto err;
7959 		}
7960 
7961 		ctx->sq_creds = get_current_cred();
7962 		ctx->sq_data = sqd;
7963 		ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
7964 		if (!ctx->sq_thread_idle)
7965 			ctx->sq_thread_idle = HZ;
7966 
7967 		io_sq_thread_park(sqd);
7968 		list_add(&ctx->sqd_list, &sqd->ctx_list);
7969 		io_sqd_update_thread_idle(sqd);
7970 		/* don't attach to a dying SQPOLL thread, would be racy */
7971 		ret = (attached && !sqd->thread) ? -ENXIO : 0;
7972 		io_sq_thread_unpark(sqd);
7973 
7974 		if (ret < 0)
7975 			goto err;
7976 		if (attached)
7977 			return 0;
7978 
7979 		if (p->flags & IORING_SETUP_SQ_AFF) {
7980 			int cpu = p->sq_thread_cpu;
7981 
7982 			ret = -EINVAL;
7983 			if (cpu >= nr_cpu_ids || !cpu_online(cpu))
7984 				goto err_sqpoll;
7985 			sqd->sq_cpu = cpu;
7986 		} else {
7987 			sqd->sq_cpu = -1;
7988 		}
7989 
7990 		sqd->task_pid = current->pid;
7991 		sqd->task_tgid = current->tgid;
7992 		tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
7993 		if (IS_ERR(tsk)) {
7994 			ret = PTR_ERR(tsk);
7995 			goto err_sqpoll;
7996 		}
7997 
7998 		sqd->thread = tsk;
7999 		ret = io_uring_alloc_task_context(tsk, ctx);
8000 		wake_up_new_task(tsk);
8001 		if (ret)
8002 			goto err;
8003 	} else if (p->flags & IORING_SETUP_SQ_AFF) {
8004 		/* Can't have SQ_AFF without SQPOLL */
8005 		ret = -EINVAL;
8006 		goto err;
8007 	}
8008 
8009 	return 0;
8010 err_sqpoll:
8011 	complete(&ctx->sq_data->exited);
8012 err:
8013 	io_sq_thread_finish(ctx);
8014 	return ret;
8015 }
8016 
__io_unaccount_mem(struct user_struct * user,unsigned long nr_pages)8017 static inline void __io_unaccount_mem(struct user_struct *user,
8018 				      unsigned long nr_pages)
8019 {
8020 	atomic_long_sub(nr_pages, &user->locked_vm);
8021 }
8022 
__io_account_mem(struct user_struct * user,unsigned long nr_pages)8023 static inline int __io_account_mem(struct user_struct *user,
8024 				   unsigned long nr_pages)
8025 {
8026 	unsigned long page_limit, cur_pages, new_pages;
8027 
8028 	/* Don't allow more pages than we can safely lock */
8029 	page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
8030 
8031 	do {
8032 		cur_pages = atomic_long_read(&user->locked_vm);
8033 		new_pages = cur_pages + nr_pages;
8034 		if (new_pages > page_limit)
8035 			return -ENOMEM;
8036 	} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
8037 					new_pages) != cur_pages);
8038 
8039 	return 0;
8040 }
8041 
io_unaccount_mem(struct io_ring_ctx * ctx,unsigned long nr_pages)8042 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
8043 {
8044 	if (ctx->user)
8045 		__io_unaccount_mem(ctx->user, nr_pages);
8046 
8047 	if (ctx->mm_account)
8048 		atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
8049 }
8050 
io_account_mem(struct io_ring_ctx * ctx,unsigned long nr_pages)8051 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
8052 {
8053 	int ret;
8054 
8055 	if (ctx->user) {
8056 		ret = __io_account_mem(ctx->user, nr_pages);
8057 		if (ret)
8058 			return ret;
8059 	}
8060 
8061 	if (ctx->mm_account)
8062 		atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
8063 
8064 	return 0;
8065 }
8066 
io_mem_free(void * ptr)8067 static void io_mem_free(void *ptr)
8068 {
8069 	struct page *page;
8070 
8071 	if (!ptr)
8072 		return;
8073 
8074 	page = virt_to_head_page(ptr);
8075 	if (put_page_testzero(page))
8076 		free_compound_page(page);
8077 }
8078 
io_mem_alloc(size_t size)8079 static void *io_mem_alloc(size_t size)
8080 {
8081 	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
8082 				__GFP_NORETRY | __GFP_ACCOUNT;
8083 
8084 	return (void *) __get_free_pages(gfp_flags, get_order(size));
8085 }
8086 
rings_size(unsigned sq_entries,unsigned cq_entries,size_t * sq_offset)8087 static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
8088 				size_t *sq_offset)
8089 {
8090 	struct io_rings *rings;
8091 	size_t off, sq_array_size;
8092 
8093 	off = struct_size(rings, cqes, cq_entries);
8094 	if (off == SIZE_MAX)
8095 		return SIZE_MAX;
8096 
8097 #ifdef CONFIG_SMP
8098 	off = ALIGN(off, SMP_CACHE_BYTES);
8099 	if (off == 0)
8100 		return SIZE_MAX;
8101 #endif
8102 
8103 	if (sq_offset)
8104 		*sq_offset = off;
8105 
8106 	sq_array_size = array_size(sizeof(u32), sq_entries);
8107 	if (sq_array_size == SIZE_MAX)
8108 		return SIZE_MAX;
8109 
8110 	if (check_add_overflow(off, sq_array_size, &off))
8111 		return SIZE_MAX;
8112 
8113 	return off;
8114 }
8115 
io_buffer_unmap(struct io_ring_ctx * ctx,struct io_mapped_ubuf ** slot)8116 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
8117 {
8118 	struct io_mapped_ubuf *imu = *slot;
8119 	unsigned int i;
8120 
8121 	if (imu != ctx->dummy_ubuf) {
8122 		for (i = 0; i < imu->nr_bvecs; i++)
8123 			unpin_user_page(imu->bvec[i].bv_page);
8124 		if (imu->acct_pages)
8125 			io_unaccount_mem(ctx, imu->acct_pages);
8126 		kvfree(imu);
8127 	}
8128 	*slot = NULL;
8129 }
8130 
io_rsrc_buf_put(struct io_ring_ctx * ctx,struct io_rsrc_put * prsrc)8131 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
8132 {
8133 	io_buffer_unmap(ctx, &prsrc->buf);
8134 	prsrc->buf = NULL;
8135 }
8136 
__io_sqe_buffers_unregister(struct io_ring_ctx * ctx)8137 static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
8138 {
8139 	unsigned int i;
8140 
8141 	for (i = 0; i < ctx->nr_user_bufs; i++)
8142 		io_buffer_unmap(ctx, &ctx->user_bufs[i]);
8143 	kfree(ctx->user_bufs);
8144 	io_rsrc_data_free(ctx->buf_data);
8145 	ctx->user_bufs = NULL;
8146 	ctx->buf_data = NULL;
8147 	ctx->nr_user_bufs = 0;
8148 }
8149 
io_sqe_buffers_unregister(struct io_ring_ctx * ctx)8150 static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
8151 {
8152 	int ret;
8153 
8154 	if (!ctx->buf_data)
8155 		return -ENXIO;
8156 
8157 	ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
8158 	if (!ret)
8159 		__io_sqe_buffers_unregister(ctx);
8160 	return ret;
8161 }
8162 
io_copy_iov(struct io_ring_ctx * ctx,struct iovec * dst,void __user * arg,unsigned index)8163 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
8164 		       void __user *arg, unsigned index)
8165 {
8166 	struct iovec __user *src;
8167 
8168 #ifdef CONFIG_COMPAT
8169 	if (ctx->compat) {
8170 		struct compat_iovec __user *ciovs;
8171 		struct compat_iovec ciov;
8172 
8173 		ciovs = (struct compat_iovec __user *) arg;
8174 		if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
8175 			return -EFAULT;
8176 
8177 		dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
8178 		dst->iov_len = ciov.iov_len;
8179 		return 0;
8180 	}
8181 #endif
8182 	src = (struct iovec __user *) arg;
8183 	if (copy_from_user(dst, &src[index], sizeof(*dst)))
8184 		return -EFAULT;
8185 	return 0;
8186 }
8187 
8188 /*
8189  * Not super efficient, but this is just a registration time. And we do cache
8190  * the last compound head, so generally we'll only do a full search if we don't
8191  * match that one.
8192  *
8193  * We check if the given compound head page has already been accounted, to
8194  * avoid double accounting it. This allows us to account the full size of the
8195  * page, not just the constituent pages of a huge page.
8196  */
headpage_already_acct(struct io_ring_ctx * ctx,struct page ** pages,int nr_pages,struct page * hpage)8197 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
8198 				  int nr_pages, struct page *hpage)
8199 {
8200 	int i, j;
8201 
8202 	/* check current page array */
8203 	for (i = 0; i < nr_pages; i++) {
8204 		if (!PageCompound(pages[i]))
8205 			continue;
8206 		if (compound_head(pages[i]) == hpage)
8207 			return true;
8208 	}
8209 
8210 	/* check previously registered pages */
8211 	for (i = 0; i < ctx->nr_user_bufs; i++) {
8212 		struct io_mapped_ubuf *imu = ctx->user_bufs[i];
8213 
8214 		for (j = 0; j < imu->nr_bvecs; j++) {
8215 			if (!PageCompound(imu->bvec[j].bv_page))
8216 				continue;
8217 			if (compound_head(imu->bvec[j].bv_page) == hpage)
8218 				return true;
8219 		}
8220 	}
8221 
8222 	return false;
8223 }
8224 
io_buffer_account_pin(struct io_ring_ctx * ctx,struct page ** pages,int nr_pages,struct io_mapped_ubuf * imu,struct page ** last_hpage)8225 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
8226 				 int nr_pages, struct io_mapped_ubuf *imu,
8227 				 struct page **last_hpage)
8228 {
8229 	int i, ret;
8230 
8231 	for (i = 0; i < nr_pages; i++) {
8232 		if (!PageCompound(pages[i])) {
8233 			imu->acct_pages++;
8234 		} else {
8235 			struct page *hpage;
8236 
8237 			hpage = compound_head(pages[i]);
8238 			if (hpage == *last_hpage)
8239 				continue;
8240 			*last_hpage = hpage;
8241 			if (headpage_already_acct(ctx, pages, i, hpage))
8242 				continue;
8243 			imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
8244 		}
8245 	}
8246 
8247 	if (!imu->acct_pages)
8248 		return 0;
8249 
8250 	ret = io_account_mem(ctx, imu->acct_pages);
8251 	if (ret)
8252 		imu->acct_pages = 0;
8253 	return ret;
8254 }
8255 
io_sqe_buffer_register(struct io_ring_ctx * ctx,struct iovec * iov,struct io_mapped_ubuf ** pimu,struct page ** last_hpage)8256 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
8257 				  struct io_mapped_ubuf **pimu,
8258 				  struct page **last_hpage)
8259 {
8260 	struct io_mapped_ubuf *imu = NULL;
8261 	struct vm_area_struct **vmas = NULL;
8262 	struct page **pages = NULL;
8263 	unsigned long off, start, end, ubuf;
8264 	size_t size;
8265 	int ret, pret, nr_pages, i;
8266 
8267 	if (!iov->iov_base) {
8268 		*pimu = ctx->dummy_ubuf;
8269 		return 0;
8270 	}
8271 
8272 	ubuf = (unsigned long) iov->iov_base;
8273 	end = (ubuf + iov->iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
8274 	start = ubuf >> PAGE_SHIFT;
8275 	nr_pages = end - start;
8276 
8277 	*pimu = NULL;
8278 	ret = -ENOMEM;
8279 
8280 	pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
8281 	if (!pages)
8282 		goto done;
8283 
8284 	vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
8285 			      GFP_KERNEL);
8286 	if (!vmas)
8287 		goto done;
8288 
8289 	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
8290 	if (!imu)
8291 		goto done;
8292 
8293 	ret = 0;
8294 	mmap_read_lock(current->mm);
8295 	pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
8296 			      pages, vmas);
8297 	if (pret == nr_pages) {
8298 		/* don't support file backed memory */
8299 		for (i = 0; i < nr_pages; i++) {
8300 			struct vm_area_struct *vma = vmas[i];
8301 
8302 			if (vma->vm_file &&
8303 			    !is_file_hugepages(vma->vm_file)) {
8304 				ret = -EOPNOTSUPP;
8305 				break;
8306 			}
8307 		}
8308 	} else {
8309 		ret = pret < 0 ? pret : -EFAULT;
8310 	}
8311 	mmap_read_unlock(current->mm);
8312 	if (ret) {
8313 		/*
8314 		 * if we did partial map, or found file backed vmas,
8315 		 * release any pages we did get
8316 		 */
8317 		if (pret > 0)
8318 			unpin_user_pages(pages, pret);
8319 		goto done;
8320 	}
8321 
8322 	ret = io_buffer_account_pin(ctx, pages, pret, imu, last_hpage);
8323 	if (ret) {
8324 		unpin_user_pages(pages, pret);
8325 		goto done;
8326 	}
8327 
8328 	off = ubuf & ~PAGE_MASK;
8329 	size = iov->iov_len;
8330 	for (i = 0; i < nr_pages; i++) {
8331 		size_t vec_len;
8332 
8333 		vec_len = min_t(size_t, size, PAGE_SIZE - off);
8334 		imu->bvec[i].bv_page = pages[i];
8335 		imu->bvec[i].bv_len = vec_len;
8336 		imu->bvec[i].bv_offset = off;
8337 		off = 0;
8338 		size -= vec_len;
8339 	}
8340 	/* store original address for later verification */
8341 	imu->ubuf = ubuf;
8342 	imu->ubuf_end = ubuf + iov->iov_len;
8343 	imu->nr_bvecs = nr_pages;
8344 	*pimu = imu;
8345 	ret = 0;
8346 done:
8347 	if (ret)
8348 		kvfree(imu);
8349 	kvfree(pages);
8350 	kvfree(vmas);
8351 	return ret;
8352 }
8353 
io_buffers_map_alloc(struct io_ring_ctx * ctx,unsigned int nr_args)8354 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
8355 {
8356 	ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
8357 	return ctx->user_bufs ? 0 : -ENOMEM;
8358 }
8359 
io_buffer_validate(struct iovec * iov)8360 static int io_buffer_validate(struct iovec *iov)
8361 {
8362 	unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
8363 
8364 	/*
8365 	 * Don't impose further limits on the size and buffer
8366 	 * constraints here, we'll -EINVAL later when IO is
8367 	 * submitted if they are wrong.
8368 	 */
8369 	if (!iov->iov_base)
8370 		return iov->iov_len ? -EFAULT : 0;
8371 	if (!iov->iov_len)
8372 		return -EFAULT;
8373 
8374 	/* arbitrary limit, but we need something */
8375 	if (iov->iov_len > SZ_1G)
8376 		return -EFAULT;
8377 
8378 	if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
8379 		return -EOVERFLOW;
8380 
8381 	return 0;
8382 }
8383 
io_sqe_buffers_register(struct io_ring_ctx * ctx,void __user * arg,unsigned int nr_args,u64 __user * tags)8384 static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
8385 				   unsigned int nr_args, u64 __user *tags)
8386 {
8387 	struct page *last_hpage = NULL;
8388 	struct io_rsrc_data *data;
8389 	int i, ret;
8390 	struct iovec iov;
8391 
8392 	if (ctx->user_bufs)
8393 		return -EBUSY;
8394 	if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
8395 		return -EINVAL;
8396 	ret = io_rsrc_node_switch_start(ctx);
8397 	if (ret)
8398 		return ret;
8399 	data = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, nr_args);
8400 	if (!data)
8401 		return -ENOMEM;
8402 	ret = io_buffers_map_alloc(ctx, nr_args);
8403 	if (ret) {
8404 		io_rsrc_data_free(data);
8405 		return ret;
8406 	}
8407 
8408 	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
8409 		u64 tag = 0;
8410 
8411 		if (tags && copy_from_user(&tag, &tags[i], sizeof(tag))) {
8412 			ret = -EFAULT;
8413 			break;
8414 		}
8415 		ret = io_copy_iov(ctx, &iov, arg, i);
8416 		if (ret)
8417 			break;
8418 		ret = io_buffer_validate(&iov);
8419 		if (ret)
8420 			break;
8421 		if (!iov.iov_base && tag) {
8422 			ret = -EINVAL;
8423 			break;
8424 		}
8425 
8426 		ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
8427 					     &last_hpage);
8428 		if (ret)
8429 			break;
8430 		data->tags[i] = tag;
8431 	}
8432 
8433 	WARN_ON_ONCE(ctx->buf_data);
8434 
8435 	ctx->buf_data = data;
8436 	if (ret)
8437 		__io_sqe_buffers_unregister(ctx);
8438 	else
8439 		io_rsrc_node_switch(ctx, NULL);
8440 	return ret;
8441 }
8442 
__io_sqe_buffers_update(struct io_ring_ctx * ctx,struct io_uring_rsrc_update2 * up,unsigned int nr_args)8443 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
8444 				   struct io_uring_rsrc_update2 *up,
8445 				   unsigned int nr_args)
8446 {
8447 	u64 __user *tags = u64_to_user_ptr(up->tags);
8448 	struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
8449 	struct page *last_hpage = NULL;
8450 	bool needs_switch = false;
8451 	__u32 done;
8452 	int i, err;
8453 
8454 	if (!ctx->buf_data)
8455 		return -ENXIO;
8456 	if (up->offset + nr_args > ctx->nr_user_bufs)
8457 		return -EINVAL;
8458 
8459 	for (done = 0; done < nr_args; done++) {
8460 		struct io_mapped_ubuf *imu;
8461 		int offset = up->offset + done;
8462 		u64 tag = 0;
8463 
8464 		err = io_copy_iov(ctx, &iov, iovs, done);
8465 		if (err)
8466 			break;
8467 		if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
8468 			err = -EFAULT;
8469 			break;
8470 		}
8471 		err = io_buffer_validate(&iov);
8472 		if (err)
8473 			break;
8474 		if (!iov.iov_base && tag) {
8475 			err = -EINVAL;
8476 			break;
8477 		}
8478 		err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
8479 		if (err)
8480 			break;
8481 
8482 		i = array_index_nospec(offset, ctx->nr_user_bufs);
8483 		if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
8484 			err = io_queue_rsrc_removal(ctx->buf_data, offset,
8485 						    ctx->rsrc_node, ctx->user_bufs[i]);
8486 			if (unlikely(err)) {
8487 				io_buffer_unmap(ctx, &imu);
8488 				break;
8489 			}
8490 			ctx->user_bufs[i] = NULL;
8491 			needs_switch = true;
8492 		}
8493 
8494 		ctx->user_bufs[i] = imu;
8495 		ctx->buf_data->tags[offset] = tag;
8496 	}
8497 
8498 	if (needs_switch)
8499 		io_rsrc_node_switch(ctx, ctx->buf_data);
8500 	return done ? done : err;
8501 }
8502 
io_eventfd_register(struct io_ring_ctx * ctx,void __user * arg)8503 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
8504 {
8505 	__s32 __user *fds = arg;
8506 	int fd;
8507 
8508 	if (ctx->cq_ev_fd)
8509 		return -EBUSY;
8510 
8511 	if (copy_from_user(&fd, fds, sizeof(*fds)))
8512 		return -EFAULT;
8513 
8514 	ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
8515 	if (IS_ERR(ctx->cq_ev_fd)) {
8516 		int ret = PTR_ERR(ctx->cq_ev_fd);
8517 		ctx->cq_ev_fd = NULL;
8518 		return ret;
8519 	}
8520 
8521 	return 0;
8522 }
8523 
io_eventfd_unregister(struct io_ring_ctx * ctx)8524 static int io_eventfd_unregister(struct io_ring_ctx *ctx)
8525 {
8526 	if (ctx->cq_ev_fd) {
8527 		eventfd_ctx_put(ctx->cq_ev_fd);
8528 		ctx->cq_ev_fd = NULL;
8529 		return 0;
8530 	}
8531 
8532 	return -ENXIO;
8533 }
8534 
io_destroy_buffers(struct io_ring_ctx * ctx)8535 static void io_destroy_buffers(struct io_ring_ctx *ctx)
8536 {
8537 	struct io_buffer *buf;
8538 	unsigned long index;
8539 
8540 	xa_for_each(&ctx->io_buffers, index, buf)
8541 		__io_remove_buffers(ctx, buf, index, -1U);
8542 }
8543 
io_req_cache_free(struct list_head * list,struct task_struct * tsk)8544 static void io_req_cache_free(struct list_head *list, struct task_struct *tsk)
8545 {
8546 	struct io_kiocb *req, *nxt;
8547 
8548 	list_for_each_entry_safe(req, nxt, list, compl.list) {
8549 		if (tsk && req->task != tsk)
8550 			continue;
8551 		list_del(&req->compl.list);
8552 		kmem_cache_free(req_cachep, req);
8553 	}
8554 }
8555 
io_req_caches_free(struct io_ring_ctx * ctx)8556 static void io_req_caches_free(struct io_ring_ctx *ctx)
8557 {
8558 	struct io_submit_state *submit_state = &ctx->submit_state;
8559 	struct io_comp_state *cs = &ctx->submit_state.comp;
8560 
8561 	mutex_lock(&ctx->uring_lock);
8562 
8563 	if (submit_state->free_reqs) {
8564 		kmem_cache_free_bulk(req_cachep, submit_state->free_reqs,
8565 				     submit_state->reqs);
8566 		submit_state->free_reqs = 0;
8567 	}
8568 
8569 	io_flush_cached_locked_reqs(ctx, cs);
8570 	io_req_cache_free(&cs->free_list, NULL);
8571 	mutex_unlock(&ctx->uring_lock);
8572 }
8573 
io_wait_rsrc_data(struct io_rsrc_data * data)8574 static bool io_wait_rsrc_data(struct io_rsrc_data *data)
8575 {
8576 	if (!data)
8577 		return false;
8578 	if (!atomic_dec_and_test(&data->refs))
8579 		wait_for_completion(&data->done);
8580 	return true;
8581 }
8582 
io_ring_ctx_free(struct io_ring_ctx * ctx)8583 static void io_ring_ctx_free(struct io_ring_ctx *ctx)
8584 {
8585 	io_sq_thread_finish(ctx);
8586 
8587 	if (ctx->mm_account) {
8588 		mmdrop(ctx->mm_account);
8589 		ctx->mm_account = NULL;
8590 	}
8591 
8592 	mutex_lock(&ctx->uring_lock);
8593 	if (io_wait_rsrc_data(ctx->buf_data))
8594 		__io_sqe_buffers_unregister(ctx);
8595 	if (io_wait_rsrc_data(ctx->file_data))
8596 		__io_sqe_files_unregister(ctx);
8597 	if (ctx->rings)
8598 		__io_cqring_overflow_flush(ctx, true);
8599 	mutex_unlock(&ctx->uring_lock);
8600 	io_eventfd_unregister(ctx);
8601 	io_destroy_buffers(ctx);
8602 	if (ctx->sq_creds)
8603 		put_cred(ctx->sq_creds);
8604 
8605 	/* there are no registered resources left, nobody uses it */
8606 	if (ctx->rsrc_node)
8607 		io_rsrc_node_destroy(ctx->rsrc_node);
8608 	if (ctx->rsrc_backup_node)
8609 		io_rsrc_node_destroy(ctx->rsrc_backup_node);
8610 	flush_delayed_work(&ctx->rsrc_put_work);
8611 
8612 	WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
8613 	WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist));
8614 
8615 #if defined(CONFIG_UNIX)
8616 	if (ctx->ring_sock) {
8617 		ctx->ring_sock->file = NULL; /* so that iput() is called */
8618 		sock_release(ctx->ring_sock);
8619 	}
8620 #endif
8621 
8622 	io_mem_free(ctx->rings);
8623 	io_mem_free(ctx->sq_sqes);
8624 
8625 	percpu_ref_exit(&ctx->refs);
8626 	free_uid(ctx->user);
8627 	io_req_caches_free(ctx);
8628 	if (ctx->hash_map)
8629 		io_wq_put_hash(ctx->hash_map);
8630 	kfree(ctx->cancel_hash);
8631 	kfree(ctx->dummy_ubuf);
8632 	kfree(ctx);
8633 }
8634 
io_uring_poll(struct file * file,poll_table * wait)8635 static __poll_t io_uring_poll(struct file *file, poll_table *wait)
8636 {
8637 	struct io_ring_ctx *ctx = file->private_data;
8638 	__poll_t mask = 0;
8639 
8640 	poll_wait(file, &ctx->cq_wait, wait);
8641 	/*
8642 	 * synchronizes with barrier from wq_has_sleeper call in
8643 	 * io_commit_cqring
8644 	 */
8645 	smp_rmb();
8646 	if (!io_sqring_full(ctx))
8647 		mask |= EPOLLOUT | EPOLLWRNORM;
8648 
8649 	/*
8650 	 * Don't flush cqring overflow list here, just do a simple check.
8651 	 * Otherwise there could possible be ABBA deadlock:
8652 	 *      CPU0                    CPU1
8653 	 *      ----                    ----
8654 	 * lock(&ctx->uring_lock);
8655 	 *                              lock(&ep->mtx);
8656 	 *                              lock(&ctx->uring_lock);
8657 	 * lock(&ep->mtx);
8658 	 *
8659 	 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
8660 	 * pushs them to do the flush.
8661 	 */
8662 	if (io_cqring_events(ctx) || test_bit(0, &ctx->cq_check_overflow))
8663 		mask |= EPOLLIN | EPOLLRDNORM;
8664 
8665 	return mask;
8666 }
8667 
io_uring_fasync(int fd,struct file * file,int on)8668 static int io_uring_fasync(int fd, struct file *file, int on)
8669 {
8670 	struct io_ring_ctx *ctx = file->private_data;
8671 
8672 	return fasync_helper(fd, file, on, &ctx->cq_fasync);
8673 }
8674 
io_unregister_personality(struct io_ring_ctx * ctx,unsigned id)8675 static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
8676 {
8677 	const struct cred *creds;
8678 
8679 	creds = xa_erase(&ctx->personalities, id);
8680 	if (creds) {
8681 		put_cred(creds);
8682 		return 0;
8683 	}
8684 
8685 	return -EINVAL;
8686 }
8687 
io_run_ctx_fallback(struct io_ring_ctx * ctx)8688 static inline bool io_run_ctx_fallback(struct io_ring_ctx *ctx)
8689 {
8690 	return io_run_task_work_head(&ctx->exit_task_work);
8691 }
8692 
8693 struct io_tctx_exit {
8694 	struct callback_head		task_work;
8695 	struct completion		completion;
8696 	struct io_ring_ctx		*ctx;
8697 };
8698 
io_tctx_exit_cb(struct callback_head * cb)8699 static void io_tctx_exit_cb(struct callback_head *cb)
8700 {
8701 	struct io_uring_task *tctx = current->io_uring;
8702 	struct io_tctx_exit *work;
8703 
8704 	work = container_of(cb, struct io_tctx_exit, task_work);
8705 	/*
8706 	 * When @in_idle, we're in cancellation and it's racy to remove the
8707 	 * node. It'll be removed by the end of cancellation, just ignore it.
8708 	 */
8709 	if (!atomic_read(&tctx->in_idle))
8710 		io_uring_del_task_file((unsigned long)work->ctx);
8711 	complete(&work->completion);
8712 }
8713 
io_cancel_ctx_cb(struct io_wq_work * work,void * data)8714 static bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
8715 {
8716 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
8717 
8718 	return req->ctx == data;
8719 }
8720 
io_ring_exit_work(struct work_struct * work)8721 static void io_ring_exit_work(struct work_struct *work)
8722 {
8723 	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
8724 	unsigned long timeout = jiffies + HZ * 60 * 5;
8725 	struct io_tctx_exit exit;
8726 	struct io_tctx_node *node;
8727 	int ret;
8728 
8729 	/*
8730 	 * If we're doing polled IO and end up having requests being
8731 	 * submitted async (out-of-line), then completions can come in while
8732 	 * we're waiting for refs to drop. We need to reap these manually,
8733 	 * as nobody else will be looking for them.
8734 	 */
8735 	do {
8736 		io_uring_try_cancel_requests(ctx, NULL, NULL);
8737 		if (ctx->sq_data) {
8738 			struct io_sq_data *sqd = ctx->sq_data;
8739 			struct task_struct *tsk;
8740 
8741 			io_sq_thread_park(sqd);
8742 			tsk = sqd->thread;
8743 			if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
8744 				io_wq_cancel_cb(tsk->io_uring->io_wq,
8745 						io_cancel_ctx_cb, ctx, true);
8746 			io_sq_thread_unpark(sqd);
8747 		}
8748 
8749 		WARN_ON_ONCE(time_after(jiffies, timeout));
8750 	} while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));
8751 
8752 	init_completion(&exit.completion);
8753 	init_task_work(&exit.task_work, io_tctx_exit_cb);
8754 	exit.ctx = ctx;
8755 	/*
8756 	 * Some may use context even when all refs and requests have been put,
8757 	 * and they are free to do so while still holding uring_lock or
8758 	 * completion_lock, see __io_req_task_submit(). Apart from other work,
8759 	 * this lock/unlock section also waits them to finish.
8760 	 */
8761 	mutex_lock(&ctx->uring_lock);
8762 	while (!list_empty(&ctx->tctx_list)) {
8763 		WARN_ON_ONCE(time_after(jiffies, timeout));
8764 
8765 		node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
8766 					ctx_node);
8767 		/* don't spin on a single task if cancellation failed */
8768 		list_rotate_left(&ctx->tctx_list);
8769 		ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
8770 		if (WARN_ON_ONCE(ret))
8771 			continue;
8772 		wake_up_process(node->task);
8773 
8774 		mutex_unlock(&ctx->uring_lock);
8775 		wait_for_completion(&exit.completion);
8776 		mutex_lock(&ctx->uring_lock);
8777 	}
8778 	mutex_unlock(&ctx->uring_lock);
8779 	spin_lock_irq(&ctx->completion_lock);
8780 	spin_unlock_irq(&ctx->completion_lock);
8781 
8782 	io_ring_ctx_free(ctx);
8783 }
8784 
8785 /* Returns true if we found and killed one or more timeouts */
io_kill_timeouts(struct io_ring_ctx * ctx,struct task_struct * tsk,struct files_struct * files)8786 static bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
8787 			     struct files_struct *files)
8788 {
8789 	struct io_kiocb *req, *tmp;
8790 	int canceled = 0;
8791 
8792 	spin_lock_irq(&ctx->completion_lock);
8793 	list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
8794 		if (io_match_task(req, tsk, files)) {
8795 			io_kill_timeout(req, -ECANCELED);
8796 			canceled++;
8797 		}
8798 	}
8799 	if (canceled != 0)
8800 		io_commit_cqring(ctx);
8801 	spin_unlock_irq(&ctx->completion_lock);
8802 	if (canceled != 0)
8803 		io_cqring_ev_posted(ctx);
8804 	return canceled != 0;
8805 }
8806 
io_ring_ctx_wait_and_kill(struct io_ring_ctx * ctx)8807 static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
8808 {
8809 	unsigned long index;
8810 	struct creds *creds;
8811 
8812 	mutex_lock(&ctx->uring_lock);
8813 	percpu_ref_kill(&ctx->refs);
8814 	if (ctx->rings)
8815 		__io_cqring_overflow_flush(ctx, true);
8816 	xa_for_each(&ctx->personalities, index, creds)
8817 		io_unregister_personality(ctx, index);
8818 	mutex_unlock(&ctx->uring_lock);
8819 
8820 	io_kill_timeouts(ctx, NULL, NULL);
8821 	io_poll_remove_all(ctx, NULL, NULL);
8822 
8823 	/* if we failed setting up the ctx, we might not have any rings */
8824 	io_iopoll_try_reap_events(ctx);
8825 
8826 	INIT_WORK(&ctx->exit_work, io_ring_exit_work);
8827 	/*
8828 	 * Use system_unbound_wq to avoid spawning tons of event kworkers
8829 	 * if we're exiting a ton of rings at the same time. It just adds
8830 	 * noise and overhead, there's no discernable change in runtime
8831 	 * over using system_wq.
8832 	 */
8833 	queue_work(system_unbound_wq, &ctx->exit_work);
8834 }
8835 
io_uring_release(struct inode * inode,struct file * file)8836 static int io_uring_release(struct inode *inode, struct file *file)
8837 {
8838 	struct io_ring_ctx *ctx = file->private_data;
8839 
8840 	file->private_data = NULL;
8841 	io_ring_ctx_wait_and_kill(ctx);
8842 	return 0;
8843 }
8844 
8845 struct io_task_cancel {
8846 	struct task_struct *task;
8847 	struct files_struct *files;
8848 };
8849 
io_cancel_task_cb(struct io_wq_work * work,void * data)8850 static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
8851 {
8852 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
8853 	struct io_task_cancel *cancel = data;
8854 	bool ret;
8855 
8856 	if (cancel->files && (req->flags & REQ_F_LINK_TIMEOUT)) {
8857 		unsigned long flags;
8858 		struct io_ring_ctx *ctx = req->ctx;
8859 
8860 		/* protect against races with linked timeouts */
8861 		spin_lock_irqsave(&ctx->completion_lock, flags);
8862 		ret = io_match_task(req, cancel->task, cancel->files);
8863 		spin_unlock_irqrestore(&ctx->completion_lock, flags);
8864 	} else {
8865 		ret = io_match_task(req, cancel->task, cancel->files);
8866 	}
8867 	return ret;
8868 }
8869 
io_cancel_defer_files(struct io_ring_ctx * ctx,struct task_struct * task,struct files_struct * files)8870 static bool io_cancel_defer_files(struct io_ring_ctx *ctx,
8871 				  struct task_struct *task,
8872 				  struct files_struct *files)
8873 {
8874 	struct io_defer_entry *de;
8875 	LIST_HEAD(list);
8876 
8877 	spin_lock_irq(&ctx->completion_lock);
8878 	list_for_each_entry_reverse(de, &ctx->defer_list, list) {
8879 		if (io_match_task(de->req, task, files)) {
8880 			list_cut_position(&list, &ctx->defer_list, &de->list);
8881 			break;
8882 		}
8883 	}
8884 	spin_unlock_irq(&ctx->completion_lock);
8885 	if (list_empty(&list))
8886 		return false;
8887 
8888 	while (!list_empty(&list)) {
8889 		de = list_first_entry(&list, struct io_defer_entry, list);
8890 		list_del_init(&de->list);
8891 		io_req_complete_failed(de->req, -ECANCELED);
8892 		kfree(de);
8893 	}
8894 	return true;
8895 }
8896 
io_uring_try_cancel_iowq(struct io_ring_ctx * ctx)8897 static bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
8898 {
8899 	struct io_tctx_node *node;
8900 	enum io_wq_cancel cret;
8901 	bool ret = false;
8902 
8903 	mutex_lock(&ctx->uring_lock);
8904 	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
8905 		struct io_uring_task *tctx = node->task->io_uring;
8906 
8907 		/*
8908 		 * io_wq will stay alive while we hold uring_lock, because it's
8909 		 * killed after ctx nodes, which requires to take the lock.
8910 		 */
8911 		if (!tctx || !tctx->io_wq)
8912 			continue;
8913 		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
8914 		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
8915 	}
8916 	mutex_unlock(&ctx->uring_lock);
8917 
8918 	return ret;
8919 }
8920 
io_uring_try_cancel_requests(struct io_ring_ctx * ctx,struct task_struct * task,struct files_struct * files)8921 static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
8922 					 struct task_struct *task,
8923 					 struct files_struct *files)
8924 {
8925 	struct io_task_cancel cancel = { .task = task, .files = files, };
8926 	struct io_uring_task *tctx = task ? task->io_uring : NULL;
8927 
8928 	while (1) {
8929 		enum io_wq_cancel cret;
8930 		bool ret = false;
8931 
8932 		if (!task) {
8933 			ret |= io_uring_try_cancel_iowq(ctx);
8934 		} else if (tctx && tctx->io_wq) {
8935 			/*
8936 			 * Cancels requests of all rings, not only @ctx, but
8937 			 * it's fine as the task is in exit/exec.
8938 			 */
8939 			cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
8940 					       &cancel, true);
8941 			ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
8942 		}
8943 
8944 		/* SQPOLL thread does its own polling */
8945 		if ((!(ctx->flags & IORING_SETUP_SQPOLL) && !files) ||
8946 		    (ctx->sq_data && ctx->sq_data->thread == current)) {
8947 			while (!list_empty_careful(&ctx->iopoll_list)) {
8948 				io_iopoll_try_reap_events(ctx);
8949 				ret = true;
8950 			}
8951 		}
8952 
8953 		ret |= io_cancel_defer_files(ctx, task, files);
8954 		ret |= io_poll_remove_all(ctx, task, files);
8955 		ret |= io_kill_timeouts(ctx, task, files);
8956 		ret |= io_run_task_work();
8957 		ret |= io_run_ctx_fallback(ctx);
8958 		if (!ret)
8959 			break;
8960 		cond_resched();
8961 	}
8962 }
8963 
__io_uring_add_task_file(struct io_ring_ctx * ctx)8964 static int __io_uring_add_task_file(struct io_ring_ctx *ctx)
8965 {
8966 	struct io_uring_task *tctx = current->io_uring;
8967 	struct io_tctx_node *node;
8968 	int ret;
8969 
8970 	if (unlikely(!tctx)) {
8971 		ret = io_uring_alloc_task_context(current, ctx);
8972 		if (unlikely(ret))
8973 			return ret;
8974 		tctx = current->io_uring;
8975 	}
8976 	if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
8977 		node = kmalloc(sizeof(*node), GFP_KERNEL);
8978 		if (!node)
8979 			return -ENOMEM;
8980 		node->ctx = ctx;
8981 		node->task = current;
8982 
8983 		ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,
8984 					node, GFP_KERNEL));
8985 		if (ret) {
8986 			kfree(node);
8987 			return ret;
8988 		}
8989 
8990 		mutex_lock(&ctx->uring_lock);
8991 		list_add(&node->ctx_node, &ctx->tctx_list);
8992 		mutex_unlock(&ctx->uring_lock);
8993 	}
8994 	tctx->last = ctx;
8995 	return 0;
8996 }
8997 
8998 /*
8999  * Note that this task has used io_uring. We use it for cancelation purposes.
9000  */
io_uring_add_task_file(struct io_ring_ctx * ctx)9001 static inline int io_uring_add_task_file(struct io_ring_ctx *ctx)
9002 {
9003 	struct io_uring_task *tctx = current->io_uring;
9004 
9005 	if (likely(tctx && tctx->last == ctx))
9006 		return 0;
9007 	return __io_uring_add_task_file(ctx);
9008 }
9009 
9010 /*
9011  * Remove this io_uring_file -> task mapping.
9012  */
io_uring_del_task_file(unsigned long index)9013 static void io_uring_del_task_file(unsigned long index)
9014 {
9015 	struct io_uring_task *tctx = current->io_uring;
9016 	struct io_tctx_node *node;
9017 
9018 	if (!tctx)
9019 		return;
9020 	node = xa_erase(&tctx->xa, index);
9021 	if (!node)
9022 		return;
9023 
9024 	WARN_ON_ONCE(current != node->task);
9025 	WARN_ON_ONCE(list_empty(&node->ctx_node));
9026 
9027 	mutex_lock(&node->ctx->uring_lock);
9028 	list_del(&node->ctx_node);
9029 	mutex_unlock(&node->ctx->uring_lock);
9030 
9031 	if (tctx->last == node->ctx)
9032 		tctx->last = NULL;
9033 	kfree(node);
9034 }
9035 
io_uring_clean_tctx(struct io_uring_task * tctx)9036 static void io_uring_clean_tctx(struct io_uring_task *tctx)
9037 {
9038 	struct io_tctx_node *node;
9039 	unsigned long index;
9040 
9041 	xa_for_each(&tctx->xa, index, node)
9042 		io_uring_del_task_file(index);
9043 	if (tctx->io_wq) {
9044 		io_wq_put_and_exit(tctx->io_wq);
9045 		tctx->io_wq = NULL;
9046 	}
9047 }
9048 
tctx_inflight(struct io_uring_task * tctx,bool tracked)9049 static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
9050 {
9051 	if (tracked)
9052 		return atomic_read(&tctx->inflight_tracked);
9053 	return percpu_counter_sum(&tctx->inflight);
9054 }
9055 
io_uring_try_cancel(struct files_struct * files)9056 static void io_uring_try_cancel(struct files_struct *files)
9057 {
9058 	struct io_uring_task *tctx = current->io_uring;
9059 	struct io_tctx_node *node;
9060 	unsigned long index;
9061 
9062 	xa_for_each(&tctx->xa, index, node) {
9063 		struct io_ring_ctx *ctx = node->ctx;
9064 
9065 		/* sqpoll task will cancel all its requests */
9066 		if (!ctx->sq_data)
9067 			io_uring_try_cancel_requests(ctx, current, files);
9068 	}
9069 }
9070 
9071 /* should only be called by SQPOLL task */
io_uring_cancel_sqpoll(struct io_sq_data * sqd)9072 static void io_uring_cancel_sqpoll(struct io_sq_data *sqd)
9073 {
9074 	struct io_uring_task *tctx = current->io_uring;
9075 	struct io_ring_ctx *ctx;
9076 	s64 inflight;
9077 	DEFINE_WAIT(wait);
9078 
9079 	if (!current->io_uring)
9080 		return;
9081 	WARN_ON_ONCE(!sqd || sqd->thread != current);
9082 
9083 	atomic_inc(&tctx->in_idle);
9084 	do {
9085 		/* read completions before cancelations */
9086 		inflight = tctx_inflight(tctx, false);
9087 		if (!inflight)
9088 			break;
9089 		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
9090 			io_uring_try_cancel_requests(ctx, current, NULL);
9091 
9092 		prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
9093 		/*
9094 		 * If we've seen completions, retry without waiting. This
9095 		 * avoids a race where a completion comes in before we did
9096 		 * prepare_to_wait().
9097 		 */
9098 		if (inflight == tctx_inflight(tctx, false))
9099 			schedule();
9100 		finish_wait(&tctx->wait, &wait);
9101 	} while (1);
9102 	atomic_dec(&tctx->in_idle);
9103 }
9104 
9105 /*
9106  * Find any io_uring fd that this task has registered or done IO on, and cancel
9107  * requests.
9108  */
__io_uring_cancel(struct files_struct * files)9109 void __io_uring_cancel(struct files_struct *files)
9110 {
9111 	struct io_uring_task *tctx = current->io_uring;
9112 	DEFINE_WAIT(wait);
9113 	s64 inflight;
9114 
9115 	/* make sure overflow events are dropped */
9116 	atomic_inc(&tctx->in_idle);
9117 	do {
9118 		/* read completions before cancelations */
9119 		inflight = tctx_inflight(tctx, !!files);
9120 		if (!inflight)
9121 			break;
9122 		io_uring_try_cancel(files);
9123 		prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
9124 
9125 		/*
9126 		 * If we've seen completions, retry without waiting. This
9127 		 * avoids a race where a completion comes in before we did
9128 		 * prepare_to_wait().
9129 		 */
9130 		if (inflight == tctx_inflight(tctx, !!files))
9131 			schedule();
9132 		finish_wait(&tctx->wait, &wait);
9133 	} while (1);
9134 	atomic_dec(&tctx->in_idle);
9135 
9136 	io_uring_clean_tctx(tctx);
9137 	if (!files) {
9138 		/* for exec all current's requests should be gone, kill tctx */
9139 		__io_uring_free(current);
9140 	}
9141 }
9142 
io_uring_validate_mmap_request(struct file * file,loff_t pgoff,size_t sz)9143 static void *io_uring_validate_mmap_request(struct file *file,
9144 					    loff_t pgoff, size_t sz)
9145 {
9146 	struct io_ring_ctx *ctx = file->private_data;
9147 	loff_t offset = pgoff << PAGE_SHIFT;
9148 	struct page *page;
9149 	void *ptr;
9150 
9151 	switch (offset) {
9152 	case IORING_OFF_SQ_RING:
9153 	case IORING_OFF_CQ_RING:
9154 		ptr = ctx->rings;
9155 		break;
9156 	case IORING_OFF_SQES:
9157 		ptr = ctx->sq_sqes;
9158 		break;
9159 	default:
9160 		return ERR_PTR(-EINVAL);
9161 	}
9162 
9163 	page = virt_to_head_page(ptr);
9164 	if (sz > page_size(page))
9165 		return ERR_PTR(-EINVAL);
9166 
9167 	return ptr;
9168 }
9169 
9170 #ifdef CONFIG_MMU
9171 
io_uring_mmap(struct file * file,struct vm_area_struct * vma)9172 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
9173 {
9174 	size_t sz = vma->vm_end - vma->vm_start;
9175 	unsigned long pfn;
9176 	void *ptr;
9177 
9178 	ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
9179 	if (IS_ERR(ptr))
9180 		return PTR_ERR(ptr);
9181 
9182 	pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
9183 	return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
9184 }
9185 
9186 #else /* !CONFIG_MMU */
9187 
io_uring_mmap(struct file * file,struct vm_area_struct * vma)9188 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
9189 {
9190 	return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
9191 }
9192 
io_uring_nommu_mmap_capabilities(struct file * file)9193 static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
9194 {
9195 	return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
9196 }
9197 
io_uring_nommu_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)9198 static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
9199 	unsigned long addr, unsigned long len,
9200 	unsigned long pgoff, unsigned long flags)
9201 {
9202 	void *ptr;
9203 
9204 	ptr = io_uring_validate_mmap_request(file, pgoff, len);
9205 	if (IS_ERR(ptr))
9206 		return PTR_ERR(ptr);
9207 
9208 	return (unsigned long) ptr;
9209 }
9210 
9211 #endif /* !CONFIG_MMU */
9212 
io_sqpoll_wait_sq(struct io_ring_ctx * ctx)9213 static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
9214 {
9215 	DEFINE_WAIT(wait);
9216 
9217 	do {
9218 		if (!io_sqring_full(ctx))
9219 			break;
9220 		prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
9221 
9222 		if (!io_sqring_full(ctx))
9223 			break;
9224 		schedule();
9225 	} while (!signal_pending(current));
9226 
9227 	finish_wait(&ctx->sqo_sq_wait, &wait);
9228 	return 0;
9229 }
9230 
io_get_ext_arg(unsigned flags,const void __user * argp,size_t * argsz,struct __kernel_timespec __user ** ts,const sigset_t __user ** sig)9231 static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
9232 			  struct __kernel_timespec __user **ts,
9233 			  const sigset_t __user **sig)
9234 {
9235 	struct io_uring_getevents_arg arg;
9236 
9237 	/*
9238 	 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
9239 	 * is just a pointer to the sigset_t.
9240 	 */
9241 	if (!(flags & IORING_ENTER_EXT_ARG)) {
9242 		*sig = (const sigset_t __user *) argp;
9243 		*ts = NULL;
9244 		return 0;
9245 	}
9246 
9247 	/*
9248 	 * EXT_ARG is set - ensure we agree on the size of it and copy in our
9249 	 * timespec and sigset_t pointers if good.
9250 	 */
9251 	if (*argsz != sizeof(arg))
9252 		return -EINVAL;
9253 	if (copy_from_user(&arg, argp, sizeof(arg)))
9254 		return -EFAULT;
9255 	*sig = u64_to_user_ptr(arg.sigmask);
9256 	*argsz = arg.sigmask_sz;
9257 	*ts = u64_to_user_ptr(arg.ts);
9258 	return 0;
9259 }
9260 
SYSCALL_DEFINE6(io_uring_enter,unsigned int,fd,u32,to_submit,u32,min_complete,u32,flags,const void __user *,argp,size_t,argsz)9261 SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
9262 		u32, min_complete, u32, flags, const void __user *, argp,
9263 		size_t, argsz)
9264 {
9265 	struct io_ring_ctx *ctx;
9266 	int submitted = 0;
9267 	struct fd f;
9268 	long ret;
9269 
9270 	io_run_task_work();
9271 
9272 	if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
9273 			       IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG)))
9274 		return -EINVAL;
9275 
9276 	f = fdget(fd);
9277 	if (unlikely(!f.file))
9278 		return -EBADF;
9279 
9280 	ret = -EOPNOTSUPP;
9281 	if (unlikely(f.file->f_op != &io_uring_fops))
9282 		goto out_fput;
9283 
9284 	ret = -ENXIO;
9285 	ctx = f.file->private_data;
9286 	if (unlikely(!percpu_ref_tryget(&ctx->refs)))
9287 		goto out_fput;
9288 
9289 	ret = -EBADFD;
9290 	if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
9291 		goto out;
9292 
9293 	/*
9294 	 * For SQ polling, the thread will do all submissions and completions.
9295 	 * Just return the requested submit count, and wake the thread if
9296 	 * we were asked to.
9297 	 */
9298 	ret = 0;
9299 	if (ctx->flags & IORING_SETUP_SQPOLL) {
9300 		io_cqring_overflow_flush(ctx, false);
9301 
9302 		ret = -EOWNERDEAD;
9303 		if (unlikely(ctx->sq_data->thread == NULL)) {
9304 			goto out;
9305 		}
9306 		if (flags & IORING_ENTER_SQ_WAKEUP)
9307 			wake_up(&ctx->sq_data->wait);
9308 		if (flags & IORING_ENTER_SQ_WAIT) {
9309 			ret = io_sqpoll_wait_sq(ctx);
9310 			if (ret)
9311 				goto out;
9312 		}
9313 		submitted = to_submit;
9314 	} else if (to_submit) {
9315 		ret = io_uring_add_task_file(ctx);
9316 		if (unlikely(ret))
9317 			goto out;
9318 		mutex_lock(&ctx->uring_lock);
9319 		submitted = io_submit_sqes(ctx, to_submit);
9320 		mutex_unlock(&ctx->uring_lock);
9321 
9322 		if (submitted != to_submit)
9323 			goto out;
9324 	}
9325 	if (flags & IORING_ENTER_GETEVENTS) {
9326 		const sigset_t __user *sig;
9327 		struct __kernel_timespec __user *ts;
9328 
9329 		ret = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
9330 		if (unlikely(ret))
9331 			goto out;
9332 
9333 		min_complete = min(min_complete, ctx->cq_entries);
9334 
9335 		/*
9336 		 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
9337 		 * space applications don't need to do io completion events
9338 		 * polling again, they can rely on io_sq_thread to do polling
9339 		 * work, which can reduce cpu usage and uring_lock contention.
9340 		 */
9341 		if (ctx->flags & IORING_SETUP_IOPOLL &&
9342 		    !(ctx->flags & IORING_SETUP_SQPOLL)) {
9343 			ret = io_iopoll_check(ctx, min_complete);
9344 		} else {
9345 			ret = io_cqring_wait(ctx, min_complete, sig, argsz, ts);
9346 		}
9347 	}
9348 
9349 out:
9350 	percpu_ref_put(&ctx->refs);
9351 out_fput:
9352 	fdput(f);
9353 	return submitted ? submitted : ret;
9354 }
9355 
9356 #ifdef CONFIG_PROC_FS
io_uring_show_cred(struct seq_file * m,unsigned int id,const struct cred * cred)9357 static int io_uring_show_cred(struct seq_file *m, unsigned int id,
9358 		const struct cred *cred)
9359 {
9360 	struct user_namespace *uns = seq_user_ns(m);
9361 	struct group_info *gi;
9362 	kernel_cap_t cap;
9363 	unsigned __capi;
9364 	int g;
9365 
9366 	seq_printf(m, "%5d\n", id);
9367 	seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
9368 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
9369 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
9370 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
9371 	seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
9372 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
9373 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
9374 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
9375 	seq_puts(m, "\n\tGroups:\t");
9376 	gi = cred->group_info;
9377 	for (g = 0; g < gi->ngroups; g++) {
9378 		seq_put_decimal_ull(m, g ? " " : "",
9379 					from_kgid_munged(uns, gi->gid[g]));
9380 	}
9381 	seq_puts(m, "\n\tCapEff:\t");
9382 	cap = cred->cap_effective;
9383 	CAP_FOR_EACH_U32(__capi)
9384 		seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8);
9385 	seq_putc(m, '\n');
9386 	return 0;
9387 }
9388 
__io_uring_show_fdinfo(struct io_ring_ctx * ctx,struct seq_file * m)9389 static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
9390 {
9391 	struct io_sq_data *sq = NULL;
9392 	bool has_lock;
9393 	int i;
9394 
9395 	/*
9396 	 * Avoid ABBA deadlock between the seq lock and the io_uring mutex,
9397 	 * since fdinfo case grabs it in the opposite direction of normal use
9398 	 * cases. If we fail to get the lock, we just don't iterate any
9399 	 * structures that could be going away outside the io_uring mutex.
9400 	 */
9401 	has_lock = mutex_trylock(&ctx->uring_lock);
9402 
9403 	if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {
9404 		sq = ctx->sq_data;
9405 		if (!sq->thread)
9406 			sq = NULL;
9407 	}
9408 
9409 	seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
9410 	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
9411 	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
9412 	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
9413 		struct file *f = io_file_from_index(ctx, i);
9414 
9415 		if (f)
9416 			seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
9417 		else
9418 			seq_printf(m, "%5u: <none>\n", i);
9419 	}
9420 	seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
9421 	for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
9422 		struct io_mapped_ubuf *buf = ctx->user_bufs[i];
9423 		unsigned int len = buf->ubuf_end - buf->ubuf;
9424 
9425 		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len);
9426 	}
9427 	if (has_lock && !xa_empty(&ctx->personalities)) {
9428 		unsigned long index;
9429 		const struct cred *cred;
9430 
9431 		seq_printf(m, "Personalities:\n");
9432 		xa_for_each(&ctx->personalities, index, cred)
9433 			io_uring_show_cred(m, index, cred);
9434 	}
9435 	seq_printf(m, "PollList:\n");
9436 	spin_lock_irq(&ctx->completion_lock);
9437 	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
9438 		struct hlist_head *list = &ctx->cancel_hash[i];
9439 		struct io_kiocb *req;
9440 
9441 		hlist_for_each_entry(req, list, hash_node)
9442 			seq_printf(m, "  op=%d, task_works=%d\n", req->opcode,
9443 					req->task->task_works != NULL);
9444 	}
9445 	spin_unlock_irq(&ctx->completion_lock);
9446 	if (has_lock)
9447 		mutex_unlock(&ctx->uring_lock);
9448 }
9449 
io_uring_show_fdinfo(struct seq_file * m,struct file * f)9450 static void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
9451 {
9452 	struct io_ring_ctx *ctx = f->private_data;
9453 
9454 	if (percpu_ref_tryget(&ctx->refs)) {
9455 		__io_uring_show_fdinfo(ctx, m);
9456 		percpu_ref_put(&ctx->refs);
9457 	}
9458 }
9459 #endif
9460 
9461 static const struct file_operations io_uring_fops = {
9462 	.release	= io_uring_release,
9463 	.mmap		= io_uring_mmap,
9464 #ifndef CONFIG_MMU
9465 	.get_unmapped_area = io_uring_nommu_get_unmapped_area,
9466 	.mmap_capabilities = io_uring_nommu_mmap_capabilities,
9467 #endif
9468 	.poll		= io_uring_poll,
9469 	.fasync		= io_uring_fasync,
9470 #ifdef CONFIG_PROC_FS
9471 	.show_fdinfo	= io_uring_show_fdinfo,
9472 #endif
9473 };
9474 
io_allocate_scq_urings(struct io_ring_ctx * ctx,struct io_uring_params * p)9475 static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
9476 				  struct io_uring_params *p)
9477 {
9478 	struct io_rings *rings;
9479 	size_t size, sq_array_offset;
9480 
9481 	/* make sure these are sane, as we already accounted them */
9482 	ctx->sq_entries = p->sq_entries;
9483 	ctx->cq_entries = p->cq_entries;
9484 
9485 	size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
9486 	if (size == SIZE_MAX)
9487 		return -EOVERFLOW;
9488 
9489 	rings = io_mem_alloc(size);
9490 	if (!rings)
9491 		return -ENOMEM;
9492 
9493 	ctx->rings = rings;
9494 	ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
9495 	rings->sq_ring_mask = p->sq_entries - 1;
9496 	rings->cq_ring_mask = p->cq_entries - 1;
9497 	rings->sq_ring_entries = p->sq_entries;
9498 	rings->cq_ring_entries = p->cq_entries;
9499 	ctx->sq_mask = rings->sq_ring_mask;
9500 	ctx->cq_mask = rings->cq_ring_mask;
9501 
9502 	size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
9503 	if (size == SIZE_MAX) {
9504 		io_mem_free(ctx->rings);
9505 		ctx->rings = NULL;
9506 		return -EOVERFLOW;
9507 	}
9508 
9509 	ctx->sq_sqes = io_mem_alloc(size);
9510 	if (!ctx->sq_sqes) {
9511 		io_mem_free(ctx->rings);
9512 		ctx->rings = NULL;
9513 		return -ENOMEM;
9514 	}
9515 
9516 	return 0;
9517 }
9518 
io_uring_install_fd(struct io_ring_ctx * ctx,struct file * file)9519 static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
9520 {
9521 	int ret, fd;
9522 
9523 	fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
9524 	if (fd < 0)
9525 		return fd;
9526 
9527 	ret = io_uring_add_task_file(ctx);
9528 	if (ret) {
9529 		put_unused_fd(fd);
9530 		return ret;
9531 	}
9532 	fd_install(fd, file);
9533 	return fd;
9534 }
9535 
9536 /*
9537  * Allocate an anonymous fd, this is what constitutes the application
9538  * visible backing of an io_uring instance. The application mmaps this
9539  * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
9540  * we have to tie this fd to a socket for file garbage collection purposes.
9541  */
io_uring_get_file(struct io_ring_ctx * ctx)9542 static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
9543 {
9544 	struct file *file;
9545 #if defined(CONFIG_UNIX)
9546 	int ret;
9547 
9548 	ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
9549 				&ctx->ring_sock);
9550 	if (ret)
9551 		return ERR_PTR(ret);
9552 #endif
9553 
9554 	file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
9555 					O_RDWR | O_CLOEXEC);
9556 #if defined(CONFIG_UNIX)
9557 	if (IS_ERR(file)) {
9558 		sock_release(ctx->ring_sock);
9559 		ctx->ring_sock = NULL;
9560 	} else {
9561 		ctx->ring_sock->file = file;
9562 	}
9563 #endif
9564 	return file;
9565 }
9566 
io_uring_create(unsigned entries,struct io_uring_params * p,struct io_uring_params __user * params)9567 static int io_uring_create(unsigned entries, struct io_uring_params *p,
9568 			   struct io_uring_params __user *params)
9569 {
9570 	struct io_ring_ctx *ctx;
9571 	struct file *file;
9572 	int ret;
9573 
9574 	if (!entries)
9575 		return -EINVAL;
9576 	if (entries > IORING_MAX_ENTRIES) {
9577 		if (!(p->flags & IORING_SETUP_CLAMP))
9578 			return -EINVAL;
9579 		entries = IORING_MAX_ENTRIES;
9580 	}
9581 
9582 	/*
9583 	 * Use twice as many entries for the CQ ring. It's possible for the
9584 	 * application to drive a higher depth than the size of the SQ ring,
9585 	 * since the sqes are only used at submission time. This allows for
9586 	 * some flexibility in overcommitting a bit. If the application has
9587 	 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
9588 	 * of CQ ring entries manually.
9589 	 */
9590 	p->sq_entries = roundup_pow_of_two(entries);
9591 	if (p->flags & IORING_SETUP_CQSIZE) {
9592 		/*
9593 		 * If IORING_SETUP_CQSIZE is set, we do the same roundup
9594 		 * to a power-of-two, if it isn't already. We do NOT impose
9595 		 * any cq vs sq ring sizing.
9596 		 */
9597 		if (!p->cq_entries)
9598 			return -EINVAL;
9599 		if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
9600 			if (!(p->flags & IORING_SETUP_CLAMP))
9601 				return -EINVAL;
9602 			p->cq_entries = IORING_MAX_CQ_ENTRIES;
9603 		}
9604 		p->cq_entries = roundup_pow_of_two(p->cq_entries);
9605 		if (p->cq_entries < p->sq_entries)
9606 			return -EINVAL;
9607 	} else {
9608 		p->cq_entries = 2 * p->sq_entries;
9609 	}
9610 
9611 	ctx = io_ring_ctx_alloc(p);
9612 	if (!ctx)
9613 		return -ENOMEM;
9614 	ctx->compat = in_compat_syscall();
9615 	if (!capable(CAP_IPC_LOCK))
9616 		ctx->user = get_uid(current_user());
9617 
9618 	/*
9619 	 * This is just grabbed for accounting purposes. When a process exits,
9620 	 * the mm is exited and dropped before the files, hence we need to hang
9621 	 * on to this mm purely for the purposes of being able to unaccount
9622 	 * memory (locked/pinned vm). It's not used for anything else.
9623 	 */
9624 	mmgrab(current->mm);
9625 	ctx->mm_account = current->mm;
9626 
9627 	ret = io_allocate_scq_urings(ctx, p);
9628 	if (ret)
9629 		goto err;
9630 
9631 	ret = io_sq_offload_create(ctx, p);
9632 	if (ret)
9633 		goto err;
9634 	/* always set a rsrc node */
9635 	ret = io_rsrc_node_switch_start(ctx);
9636 	if (ret)
9637 		goto err;
9638 	io_rsrc_node_switch(ctx, NULL);
9639 
9640 	memset(&p->sq_off, 0, sizeof(p->sq_off));
9641 	p->sq_off.head = offsetof(struct io_rings, sq.head);
9642 	p->sq_off.tail = offsetof(struct io_rings, sq.tail);
9643 	p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
9644 	p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
9645 	p->sq_off.flags = offsetof(struct io_rings, sq_flags);
9646 	p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
9647 	p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
9648 
9649 	memset(&p->cq_off, 0, sizeof(p->cq_off));
9650 	p->cq_off.head = offsetof(struct io_rings, cq.head);
9651 	p->cq_off.tail = offsetof(struct io_rings, cq.tail);
9652 	p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
9653 	p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
9654 	p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
9655 	p->cq_off.cqes = offsetof(struct io_rings, cqes);
9656 	p->cq_off.flags = offsetof(struct io_rings, cq_flags);
9657 
9658 	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
9659 			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
9660 			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
9661 			IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
9662 			IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS;
9663 
9664 	if (copy_to_user(params, p, sizeof(*p))) {
9665 		ret = -EFAULT;
9666 		goto err;
9667 	}
9668 
9669 	file = io_uring_get_file(ctx);
9670 	if (IS_ERR(file)) {
9671 		ret = PTR_ERR(file);
9672 		goto err;
9673 	}
9674 
9675 	/*
9676 	 * Install ring fd as the very last thing, so we don't risk someone
9677 	 * having closed it before we finish setup
9678 	 */
9679 	ret = io_uring_install_fd(ctx, file);
9680 	if (ret < 0) {
9681 		/* fput will clean it up */
9682 		fput(file);
9683 		return ret;
9684 	}
9685 
9686 	trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
9687 	return ret;
9688 err:
9689 	io_ring_ctx_wait_and_kill(ctx);
9690 	return ret;
9691 }
9692 
9693 /*
9694  * Sets up an aio uring context, and returns the fd. Applications asks for a
9695  * ring size, we return the actual sq/cq ring sizes (among other things) in the
9696  * params structure passed in.
9697  */
io_uring_setup(u32 entries,struct io_uring_params __user * params)9698 static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
9699 {
9700 	struct io_uring_params p;
9701 	int i;
9702 
9703 	if (copy_from_user(&p, params, sizeof(p)))
9704 		return -EFAULT;
9705 	for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
9706 		if (p.resv[i])
9707 			return -EINVAL;
9708 	}
9709 
9710 	if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
9711 			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
9712 			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
9713 			IORING_SETUP_R_DISABLED))
9714 		return -EINVAL;
9715 
9716 	return  io_uring_create(entries, &p, params);
9717 }
9718 
SYSCALL_DEFINE2(io_uring_setup,u32,entries,struct io_uring_params __user *,params)9719 SYSCALL_DEFINE2(io_uring_setup, u32, entries,
9720 		struct io_uring_params __user *, params)
9721 {
9722 	return io_uring_setup(entries, params);
9723 }
9724 
io_probe(struct io_ring_ctx * ctx,void __user * arg,unsigned nr_args)9725 static int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
9726 {
9727 	struct io_uring_probe *p;
9728 	size_t size;
9729 	int i, ret;
9730 
9731 	size = struct_size(p, ops, nr_args);
9732 	if (size == SIZE_MAX)
9733 		return -EOVERFLOW;
9734 	p = kzalloc(size, GFP_KERNEL);
9735 	if (!p)
9736 		return -ENOMEM;
9737 
9738 	ret = -EFAULT;
9739 	if (copy_from_user(p, arg, size))
9740 		goto out;
9741 	ret = -EINVAL;
9742 	if (memchr_inv(p, 0, size))
9743 		goto out;
9744 
9745 	p->last_op = IORING_OP_LAST - 1;
9746 	if (nr_args > IORING_OP_LAST)
9747 		nr_args = IORING_OP_LAST;
9748 
9749 	for (i = 0; i < nr_args; i++) {
9750 		p->ops[i].op = i;
9751 		if (!io_op_defs[i].not_supported)
9752 			p->ops[i].flags = IO_URING_OP_SUPPORTED;
9753 	}
9754 	p->ops_len = i;
9755 
9756 	ret = 0;
9757 	if (copy_to_user(arg, p, size))
9758 		ret = -EFAULT;
9759 out:
9760 	kfree(p);
9761 	return ret;
9762 }
9763 
io_register_personality(struct io_ring_ctx * ctx)9764 static int io_register_personality(struct io_ring_ctx *ctx)
9765 {
9766 	const struct cred *creds;
9767 	u32 id;
9768 	int ret;
9769 
9770 	creds = get_current_cred();
9771 
9772 	ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
9773 			XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
9774 	if (!ret)
9775 		return id;
9776 	put_cred(creds);
9777 	return ret;
9778 }
9779 
io_register_restrictions(struct io_ring_ctx * ctx,void __user * arg,unsigned int nr_args)9780 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
9781 				    unsigned int nr_args)
9782 {
9783 	struct io_uring_restriction *res;
9784 	size_t size;
9785 	int i, ret;
9786 
9787 	/* Restrictions allowed only if rings started disabled */
9788 	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
9789 		return -EBADFD;
9790 
9791 	/* We allow only a single restrictions registration */
9792 	if (ctx->restrictions.registered)
9793 		return -EBUSY;
9794 
9795 	if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
9796 		return -EINVAL;
9797 
9798 	size = array_size(nr_args, sizeof(*res));
9799 	if (size == SIZE_MAX)
9800 		return -EOVERFLOW;
9801 
9802 	res = memdup_user(arg, size);
9803 	if (IS_ERR(res))
9804 		return PTR_ERR(res);
9805 
9806 	ret = 0;
9807 
9808 	for (i = 0; i < nr_args; i++) {
9809 		switch (res[i].opcode) {
9810 		case IORING_RESTRICTION_REGISTER_OP:
9811 			if (res[i].register_op >= IORING_REGISTER_LAST) {
9812 				ret = -EINVAL;
9813 				goto out;
9814 			}
9815 
9816 			__set_bit(res[i].register_op,
9817 				  ctx->restrictions.register_op);
9818 			break;
9819 		case IORING_RESTRICTION_SQE_OP:
9820 			if (res[i].sqe_op >= IORING_OP_LAST) {
9821 				ret = -EINVAL;
9822 				goto out;
9823 			}
9824 
9825 			__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
9826 			break;
9827 		case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
9828 			ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
9829 			break;
9830 		case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
9831 			ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
9832 			break;
9833 		default:
9834 			ret = -EINVAL;
9835 			goto out;
9836 		}
9837 	}
9838 
9839 out:
9840 	/* Reset all restrictions if an error happened */
9841 	if (ret != 0)
9842 		memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
9843 	else
9844 		ctx->restrictions.registered = true;
9845 
9846 	kfree(res);
9847 	return ret;
9848 }
9849 
io_register_enable_rings(struct io_ring_ctx * ctx)9850 static int io_register_enable_rings(struct io_ring_ctx *ctx)
9851 {
9852 	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
9853 		return -EBADFD;
9854 
9855 	if (ctx->restrictions.registered)
9856 		ctx->restricted = 1;
9857 
9858 	ctx->flags &= ~IORING_SETUP_R_DISABLED;
9859 	if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait))
9860 		wake_up(&ctx->sq_data->wait);
9861 	return 0;
9862 }
9863 
__io_register_rsrc_update(struct io_ring_ctx * ctx,unsigned type,struct io_uring_rsrc_update2 * up,unsigned nr_args)9864 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
9865 				     struct io_uring_rsrc_update2 *up,
9866 				     unsigned nr_args)
9867 {
9868 	__u32 tmp;
9869 	int err;
9870 
9871 	if (up->resv)
9872 		return -EINVAL;
9873 	if (check_add_overflow(up->offset, nr_args, &tmp))
9874 		return -EOVERFLOW;
9875 	err = io_rsrc_node_switch_start(ctx);
9876 	if (err)
9877 		return err;
9878 
9879 	switch (type) {
9880 	case IORING_RSRC_FILE:
9881 		return __io_sqe_files_update(ctx, up, nr_args);
9882 	case IORING_RSRC_BUFFER:
9883 		return __io_sqe_buffers_update(ctx, up, nr_args);
9884 	}
9885 	return -EINVAL;
9886 }
9887 
io_register_files_update(struct io_ring_ctx * ctx,void __user * arg,unsigned nr_args)9888 static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
9889 				    unsigned nr_args)
9890 {
9891 	struct io_uring_rsrc_update2 up;
9892 
9893 	if (!nr_args)
9894 		return -EINVAL;
9895 	memset(&up, 0, sizeof(up));
9896 	if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
9897 		return -EFAULT;
9898 	return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
9899 }
9900 
io_register_rsrc_update(struct io_ring_ctx * ctx,void __user * arg,unsigned size)9901 static int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
9902 				   unsigned size)
9903 {
9904 	struct io_uring_rsrc_update2 up;
9905 
9906 	if (size != sizeof(up))
9907 		return -EINVAL;
9908 	if (copy_from_user(&up, arg, sizeof(up)))
9909 		return -EFAULT;
9910 	if (!up.nr)
9911 		return -EINVAL;
9912 	return __io_register_rsrc_update(ctx, up.type, &up, up.nr);
9913 }
9914 
io_register_rsrc(struct io_ring_ctx * ctx,void __user * arg,unsigned int size)9915 static int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
9916 			    unsigned int size)
9917 {
9918 	struct io_uring_rsrc_register rr;
9919 
9920 	/* keep it extendible */
9921 	if (size != sizeof(rr))
9922 		return -EINVAL;
9923 
9924 	memset(&rr, 0, sizeof(rr));
9925 	if (copy_from_user(&rr, arg, size))
9926 		return -EFAULT;
9927 	if (!rr.nr)
9928 		return -EINVAL;
9929 
9930 	switch (rr.type) {
9931 	case IORING_RSRC_FILE:
9932 		return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
9933 					     rr.nr, u64_to_user_ptr(rr.tags));
9934 	case IORING_RSRC_BUFFER:
9935 		return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
9936 					       rr.nr, u64_to_user_ptr(rr.tags));
9937 	}
9938 	return -EINVAL;
9939 }
9940 
io_register_op_must_quiesce(int op)9941 static bool io_register_op_must_quiesce(int op)
9942 {
9943 	switch (op) {
9944 	case IORING_REGISTER_BUFFERS:
9945 	case IORING_UNREGISTER_BUFFERS:
9946 	case IORING_REGISTER_FILES:
9947 	case IORING_UNREGISTER_FILES:
9948 	case IORING_REGISTER_FILES_UPDATE:
9949 	case IORING_REGISTER_PROBE:
9950 	case IORING_REGISTER_PERSONALITY:
9951 	case IORING_UNREGISTER_PERSONALITY:
9952 	case IORING_REGISTER_RSRC:
9953 	case IORING_REGISTER_RSRC_UPDATE:
9954 		return false;
9955 	default:
9956 		return true;
9957 	}
9958 }
9959 
__io_uring_register(struct io_ring_ctx * ctx,unsigned opcode,void __user * arg,unsigned nr_args)9960 static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
9961 			       void __user *arg, unsigned nr_args)
9962 	__releases(ctx->uring_lock)
9963 	__acquires(ctx->uring_lock)
9964 {
9965 	int ret;
9966 
9967 	/*
9968 	 * We're inside the ring mutex, if the ref is already dying, then
9969 	 * someone else killed the ctx or is already going through
9970 	 * io_uring_register().
9971 	 */
9972 	if (percpu_ref_is_dying(&ctx->refs))
9973 		return -ENXIO;
9974 
9975 	if (ctx->restricted) {
9976 		if (opcode >= IORING_REGISTER_LAST)
9977 			return -EINVAL;
9978 		opcode = array_index_nospec(opcode, IORING_REGISTER_LAST);
9979 		if (!test_bit(opcode, ctx->restrictions.register_op))
9980 			return -EACCES;
9981 	}
9982 
9983 	if (io_register_op_must_quiesce(opcode)) {
9984 		percpu_ref_kill(&ctx->refs);
9985 
9986 		/*
9987 		 * Drop uring mutex before waiting for references to exit. If
9988 		 * another thread is currently inside io_uring_enter() it might
9989 		 * need to grab the uring_lock to make progress. If we hold it
9990 		 * here across the drain wait, then we can deadlock. It's safe
9991 		 * to drop the mutex here, since no new references will come in
9992 		 * after we've killed the percpu ref.
9993 		 */
9994 		mutex_unlock(&ctx->uring_lock);
9995 		do {
9996 			ret = wait_for_completion_interruptible(&ctx->ref_comp);
9997 			if (!ret)
9998 				break;
9999 			ret = io_run_task_work_sig();
10000 			if (ret < 0)
10001 				break;
10002 		} while (1);
10003 		mutex_lock(&ctx->uring_lock);
10004 
10005 		if (ret) {
10006 			io_refs_resurrect(&ctx->refs, &ctx->ref_comp);
10007 			return ret;
10008 		}
10009 	}
10010 
10011 	switch (opcode) {
10012 	case IORING_REGISTER_BUFFERS:
10013 		ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
10014 		break;
10015 	case IORING_UNREGISTER_BUFFERS:
10016 		ret = -EINVAL;
10017 		if (arg || nr_args)
10018 			break;
10019 		ret = io_sqe_buffers_unregister(ctx);
10020 		break;
10021 	case IORING_REGISTER_FILES:
10022 		ret = io_sqe_files_register(ctx, arg, nr_args, NULL);
10023 		break;
10024 	case IORING_UNREGISTER_FILES:
10025 		ret = -EINVAL;
10026 		if (arg || nr_args)
10027 			break;
10028 		ret = io_sqe_files_unregister(ctx);
10029 		break;
10030 	case IORING_REGISTER_FILES_UPDATE:
10031 		ret = io_register_files_update(ctx, arg, nr_args);
10032 		break;
10033 	case IORING_REGISTER_EVENTFD:
10034 	case IORING_REGISTER_EVENTFD_ASYNC:
10035 		ret = -EINVAL;
10036 		if (nr_args != 1)
10037 			break;
10038 		ret = io_eventfd_register(ctx, arg);
10039 		if (ret)
10040 			break;
10041 		if (opcode == IORING_REGISTER_EVENTFD_ASYNC)
10042 			ctx->eventfd_async = 1;
10043 		else
10044 			ctx->eventfd_async = 0;
10045 		break;
10046 	case IORING_UNREGISTER_EVENTFD:
10047 		ret = -EINVAL;
10048 		if (arg || nr_args)
10049 			break;
10050 		ret = io_eventfd_unregister(ctx);
10051 		break;
10052 	case IORING_REGISTER_PROBE:
10053 		ret = -EINVAL;
10054 		if (!arg || nr_args > 256)
10055 			break;
10056 		ret = io_probe(ctx, arg, nr_args);
10057 		break;
10058 	case IORING_REGISTER_PERSONALITY:
10059 		ret = -EINVAL;
10060 		if (arg || nr_args)
10061 			break;
10062 		ret = io_register_personality(ctx);
10063 		break;
10064 	case IORING_UNREGISTER_PERSONALITY:
10065 		ret = -EINVAL;
10066 		if (arg)
10067 			break;
10068 		ret = io_unregister_personality(ctx, nr_args);
10069 		break;
10070 	case IORING_REGISTER_ENABLE_RINGS:
10071 		ret = -EINVAL;
10072 		if (arg || nr_args)
10073 			break;
10074 		ret = io_register_enable_rings(ctx);
10075 		break;
10076 	case IORING_REGISTER_RESTRICTIONS:
10077 		ret = io_register_restrictions(ctx, arg, nr_args);
10078 		break;
10079 	case IORING_REGISTER_RSRC:
10080 		ret = io_register_rsrc(ctx, arg, nr_args);
10081 		break;
10082 	case IORING_REGISTER_RSRC_UPDATE:
10083 		ret = io_register_rsrc_update(ctx, arg, nr_args);
10084 		break;
10085 	default:
10086 		ret = -EINVAL;
10087 		break;
10088 	}
10089 
10090 	if (io_register_op_must_quiesce(opcode)) {
10091 		/* bring the ctx back to life */
10092 		percpu_ref_reinit(&ctx->refs);
10093 		reinit_completion(&ctx->ref_comp);
10094 	}
10095 	return ret;
10096 }
10097 
SYSCALL_DEFINE4(io_uring_register,unsigned int,fd,unsigned int,opcode,void __user *,arg,unsigned int,nr_args)10098 SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
10099 		void __user *, arg, unsigned int, nr_args)
10100 {
10101 	struct io_ring_ctx *ctx;
10102 	long ret = -EBADF;
10103 	struct fd f;
10104 
10105 	f = fdget(fd);
10106 	if (!f.file)
10107 		return -EBADF;
10108 
10109 	ret = -EOPNOTSUPP;
10110 	if (f.file->f_op != &io_uring_fops)
10111 		goto out_fput;
10112 
10113 	ctx = f.file->private_data;
10114 
10115 	io_run_task_work();
10116 
10117 	mutex_lock(&ctx->uring_lock);
10118 	ret = __io_uring_register(ctx, opcode, arg, nr_args);
10119 	mutex_unlock(&ctx->uring_lock);
10120 	trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
10121 							ctx->cq_ev_fd != NULL, ret);
10122 out_fput:
10123 	fdput(f);
10124 	return ret;
10125 }
10126 
io_uring_init(void)10127 static int __init io_uring_init(void)
10128 {
10129 #define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \
10130 	BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
10131 	BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \
10132 } while (0)
10133 
10134 #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
10135 	__BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename)
10136 	BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
10137 	BUILD_BUG_SQE_ELEM(0,  __u8,   opcode);
10138 	BUILD_BUG_SQE_ELEM(1,  __u8,   flags);
10139 	BUILD_BUG_SQE_ELEM(2,  __u16,  ioprio);
10140 	BUILD_BUG_SQE_ELEM(4,  __s32,  fd);
10141 	BUILD_BUG_SQE_ELEM(8,  __u64,  off);
10142 	BUILD_BUG_SQE_ELEM(8,  __u64,  addr2);
10143 	BUILD_BUG_SQE_ELEM(16, __u64,  addr);
10144 	BUILD_BUG_SQE_ELEM(16, __u64,  splice_off_in);
10145 	BUILD_BUG_SQE_ELEM(24, __u32,  len);
10146 	BUILD_BUG_SQE_ELEM(28,     __kernel_rwf_t, rw_flags);
10147 	BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);
10148 	BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
10149 	BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);
10150 	BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);
10151 	BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);
10152 	BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);
10153 	BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);
10154 	BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);
10155 	BUILD_BUG_SQE_ELEM(28, __u32,  accept_flags);
10156 	BUILD_BUG_SQE_ELEM(28, __u32,  cancel_flags);
10157 	BUILD_BUG_SQE_ELEM(28, __u32,  open_flags);
10158 	BUILD_BUG_SQE_ELEM(28, __u32,  statx_flags);
10159 	BUILD_BUG_SQE_ELEM(28, __u32,  fadvise_advice);
10160 	BUILD_BUG_SQE_ELEM(28, __u32,  splice_flags);
10161 	BUILD_BUG_SQE_ELEM(32, __u64,  user_data);
10162 	BUILD_BUG_SQE_ELEM(40, __u16,  buf_index);
10163 	BUILD_BUG_SQE_ELEM(42, __u16,  personality);
10164 	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);
10165 
10166 	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
10167 		     sizeof(struct io_uring_rsrc_update));
10168 	BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
10169 		     sizeof(struct io_uring_rsrc_update2));
10170 	/* should fit into one byte */
10171 	BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
10172 
10173 	BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
10174 	BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
10175 	req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
10176 				SLAB_ACCOUNT);
10177 	return 0;
10178 };
10179 __initcall(io_uring_init);
10180