1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PAGEMAP_H
3 #define _LINUX_PAGEMAP_H
4
5 /*
6 * Copyright 1995 Linus Torvalds
7 */
8 #include <linux/mm.h>
9 #include <linux/fs.h>
10 #include <linux/list.h>
11 #include <linux/highmem.h>
12 #include <linux/compiler.h>
13 #include <linux/uaccess.h>
14 #include <linux/gfp.h>
15 #include <linux/bitops.h>
16 #include <linux/hardirq.h> /* for in_interrupt() */
17 #include <linux/hugetlb_inline.h>
18
19 struct folio_batch;
20
21 unsigned long invalidate_mapping_pages(struct address_space *mapping,
22 pgoff_t start, pgoff_t end);
23
invalidate_remote_inode(struct inode * inode)24 static inline void invalidate_remote_inode(struct inode *inode)
25 {
26 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
27 S_ISLNK(inode->i_mode))
28 invalidate_mapping_pages(inode->i_mapping, 0, -1);
29 }
30 int invalidate_inode_pages2(struct address_space *mapping);
31 int invalidate_inode_pages2_range(struct address_space *mapping,
32 pgoff_t start, pgoff_t end);
33 int kiocb_invalidate_pages(struct kiocb *iocb, size_t count);
34 void kiocb_invalidate_post_direct_write(struct kiocb *iocb, size_t count);
35
36 int write_inode_now(struct inode *, int sync);
37 int filemap_fdatawrite(struct address_space *);
38 int filemap_flush(struct address_space *);
39 int filemap_fdatawait_keep_errors(struct address_space *mapping);
40 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
41 int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
42 loff_t start_byte, loff_t end_byte);
43 int filemap_invalidate_inode(struct inode *inode, bool flush,
44 loff_t start, loff_t end);
45
filemap_fdatawait(struct address_space * mapping)46 static inline int filemap_fdatawait(struct address_space *mapping)
47 {
48 return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
49 }
50
51 bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend);
52 int filemap_write_and_wait_range(struct address_space *mapping,
53 loff_t lstart, loff_t lend);
54 int __filemap_fdatawrite_range(struct address_space *mapping,
55 loff_t start, loff_t end, int sync_mode);
56 int filemap_fdatawrite_range(struct address_space *mapping,
57 loff_t start, loff_t end);
58 int filemap_check_errors(struct address_space *mapping);
59 void __filemap_set_wb_err(struct address_space *mapping, int err);
60 int filemap_fdatawrite_wbc(struct address_space *mapping,
61 struct writeback_control *wbc);
62 int kiocb_write_and_wait(struct kiocb *iocb, size_t count);
63
filemap_write_and_wait(struct address_space * mapping)64 static inline int filemap_write_and_wait(struct address_space *mapping)
65 {
66 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX);
67 }
68
69 /**
70 * filemap_set_wb_err - set a writeback error on an address_space
71 * @mapping: mapping in which to set writeback error
72 * @err: error to be set in mapping
73 *
74 * When writeback fails in some way, we must record that error so that
75 * userspace can be informed when fsync and the like are called. We endeavor
76 * to report errors on any file that was open at the time of the error. Some
77 * internal callers also need to know when writeback errors have occurred.
78 *
79 * When a writeback error occurs, most filesystems will want to call
80 * filemap_set_wb_err to record the error in the mapping so that it will be
81 * automatically reported whenever fsync is called on the file.
82 */
filemap_set_wb_err(struct address_space * mapping,int err)83 static inline void filemap_set_wb_err(struct address_space *mapping, int err)
84 {
85 /* Fastpath for common case of no error */
86 if (unlikely(err))
87 __filemap_set_wb_err(mapping, err);
88 }
89
90 /**
91 * filemap_check_wb_err - has an error occurred since the mark was sampled?
92 * @mapping: mapping to check for writeback errors
93 * @since: previously-sampled errseq_t
94 *
95 * Grab the errseq_t value from the mapping, and see if it has changed "since"
96 * the given value was sampled.
97 *
98 * If it has then report the latest error set, otherwise return 0.
99 */
filemap_check_wb_err(struct address_space * mapping,errseq_t since)100 static inline int filemap_check_wb_err(struct address_space *mapping,
101 errseq_t since)
102 {
103 return errseq_check(&mapping->wb_err, since);
104 }
105
106 /**
107 * filemap_sample_wb_err - sample the current errseq_t to test for later errors
108 * @mapping: mapping to be sampled
109 *
110 * Writeback errors are always reported relative to a particular sample point
111 * in the past. This function provides those sample points.
112 */
filemap_sample_wb_err(struct address_space * mapping)113 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
114 {
115 return errseq_sample(&mapping->wb_err);
116 }
117
118 /**
119 * file_sample_sb_err - sample the current errseq_t to test for later errors
120 * @file: file pointer to be sampled
121 *
122 * Grab the most current superblock-level errseq_t value for the given
123 * struct file.
124 */
file_sample_sb_err(struct file * file)125 static inline errseq_t file_sample_sb_err(struct file *file)
126 {
127 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err);
128 }
129
130 /*
131 * Flush file data before changing attributes. Caller must hold any locks
132 * required to prevent further writes to this file until we're done setting
133 * flags.
134 */
inode_drain_writes(struct inode * inode)135 static inline int inode_drain_writes(struct inode *inode)
136 {
137 inode_dio_wait(inode);
138 return filemap_write_and_wait(inode->i_mapping);
139 }
140
mapping_empty(struct address_space * mapping)141 static inline bool mapping_empty(struct address_space *mapping)
142 {
143 return xa_empty(&mapping->i_pages);
144 }
145
146 /*
147 * mapping_shrinkable - test if page cache state allows inode reclaim
148 * @mapping: the page cache mapping
149 *
150 * This checks the mapping's cache state for the pupose of inode
151 * reclaim and LRU management.
152 *
153 * The caller is expected to hold the i_lock, but is not required to
154 * hold the i_pages lock, which usually protects cache state. That's
155 * because the i_lock and the list_lru lock that protect the inode and
156 * its LRU state don't nest inside the irq-safe i_pages lock.
157 *
158 * Cache deletions are performed under the i_lock, which ensures that
159 * when an inode goes empty, it will reliably get queued on the LRU.
160 *
161 * Cache additions do not acquire the i_lock and may race with this
162 * check, in which case we'll report the inode as shrinkable when it
163 * has cache pages. This is okay: the shrinker also checks the
164 * refcount and the referenced bit, which will be elevated or set in
165 * the process of adding new cache pages to an inode.
166 */
mapping_shrinkable(struct address_space * mapping)167 static inline bool mapping_shrinkable(struct address_space *mapping)
168 {
169 void *head;
170
171 /*
172 * On highmem systems, there could be lowmem pressure from the
173 * inodes before there is highmem pressure from the page
174 * cache. Make inodes shrinkable regardless of cache state.
175 */
176 if (IS_ENABLED(CONFIG_HIGHMEM))
177 return true;
178
179 /* Cache completely empty? Shrink away. */
180 head = rcu_access_pointer(mapping->i_pages.xa_head);
181 if (!head)
182 return true;
183
184 /*
185 * The xarray stores single offset-0 entries directly in the
186 * head pointer, which allows non-resident page cache entries
187 * to escape the shadow shrinker's list of xarray nodes. The
188 * inode shrinker needs to pick them up under memory pressure.
189 */
190 if (!xa_is_node(head) && xa_is_value(head))
191 return true;
192
193 return false;
194 }
195
196 /*
197 * Bits in mapping->flags.
198 */
199 enum mapping_flags {
200 AS_EIO = 0, /* IO error on async write */
201 AS_ENOSPC = 1, /* ENOSPC on async write */
202 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */
203 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */
204 AS_EXITING = 4, /* final truncate in progress */
205 /* writeback related tags are not used */
206 AS_NO_WRITEBACK_TAGS = 5,
207 AS_LARGE_FOLIO_SUPPORT = 6,
208 AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */
209 AS_STABLE_WRITES, /* must wait for writeback before modifying
210 folio contents */
211 AS_UNMOVABLE, /* The mapping cannot be moved, ever */
212 };
213
214 /**
215 * mapping_set_error - record a writeback error in the address_space
216 * @mapping: the mapping in which an error should be set
217 * @error: the error to set in the mapping
218 *
219 * When writeback fails in some way, we must record that error so that
220 * userspace can be informed when fsync and the like are called. We endeavor
221 * to report errors on any file that was open at the time of the error. Some
222 * internal callers also need to know when writeback errors have occurred.
223 *
224 * When a writeback error occurs, most filesystems will want to call
225 * mapping_set_error to record the error in the mapping so that it can be
226 * reported when the application calls fsync(2).
227 */
mapping_set_error(struct address_space * mapping,int error)228 static inline void mapping_set_error(struct address_space *mapping, int error)
229 {
230 if (likely(!error))
231 return;
232
233 /* Record in wb_err for checkers using errseq_t based tracking */
234 __filemap_set_wb_err(mapping, error);
235
236 /* Record it in superblock */
237 if (mapping->host)
238 errseq_set(&mapping->host->i_sb->s_wb_err, error);
239
240 /* Record it in flags for now, for legacy callers */
241 if (error == -ENOSPC)
242 set_bit(AS_ENOSPC, &mapping->flags);
243 else
244 set_bit(AS_EIO, &mapping->flags);
245 }
246
mapping_set_unevictable(struct address_space * mapping)247 static inline void mapping_set_unevictable(struct address_space *mapping)
248 {
249 set_bit(AS_UNEVICTABLE, &mapping->flags);
250 }
251
mapping_clear_unevictable(struct address_space * mapping)252 static inline void mapping_clear_unevictable(struct address_space *mapping)
253 {
254 clear_bit(AS_UNEVICTABLE, &mapping->flags);
255 }
256
mapping_unevictable(struct address_space * mapping)257 static inline bool mapping_unevictable(struct address_space *mapping)
258 {
259 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags);
260 }
261
mapping_set_exiting(struct address_space * mapping)262 static inline void mapping_set_exiting(struct address_space *mapping)
263 {
264 set_bit(AS_EXITING, &mapping->flags);
265 }
266
mapping_exiting(struct address_space * mapping)267 static inline int mapping_exiting(struct address_space *mapping)
268 {
269 return test_bit(AS_EXITING, &mapping->flags);
270 }
271
mapping_set_no_writeback_tags(struct address_space * mapping)272 static inline void mapping_set_no_writeback_tags(struct address_space *mapping)
273 {
274 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
275 }
276
mapping_use_writeback_tags(struct address_space * mapping)277 static inline int mapping_use_writeback_tags(struct address_space *mapping)
278 {
279 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags);
280 }
281
mapping_release_always(const struct address_space * mapping)282 static inline bool mapping_release_always(const struct address_space *mapping)
283 {
284 return test_bit(AS_RELEASE_ALWAYS, &mapping->flags);
285 }
286
mapping_set_release_always(struct address_space * mapping)287 static inline void mapping_set_release_always(struct address_space *mapping)
288 {
289 set_bit(AS_RELEASE_ALWAYS, &mapping->flags);
290 }
291
mapping_clear_release_always(struct address_space * mapping)292 static inline void mapping_clear_release_always(struct address_space *mapping)
293 {
294 clear_bit(AS_RELEASE_ALWAYS, &mapping->flags);
295 }
296
mapping_stable_writes(const struct address_space * mapping)297 static inline bool mapping_stable_writes(const struct address_space *mapping)
298 {
299 return test_bit(AS_STABLE_WRITES, &mapping->flags);
300 }
301
mapping_set_stable_writes(struct address_space * mapping)302 static inline void mapping_set_stable_writes(struct address_space *mapping)
303 {
304 set_bit(AS_STABLE_WRITES, &mapping->flags);
305 }
306
mapping_clear_stable_writes(struct address_space * mapping)307 static inline void mapping_clear_stable_writes(struct address_space *mapping)
308 {
309 clear_bit(AS_STABLE_WRITES, &mapping->flags);
310 }
311
mapping_set_unmovable(struct address_space * mapping)312 static inline void mapping_set_unmovable(struct address_space *mapping)
313 {
314 /*
315 * It's expected unmovable mappings are also unevictable. Compaction
316 * migrate scanner (isolate_migratepages_block()) relies on this to
317 * reduce page locking.
318 */
319 set_bit(AS_UNEVICTABLE, &mapping->flags);
320 set_bit(AS_UNMOVABLE, &mapping->flags);
321 }
322
mapping_unmovable(struct address_space * mapping)323 static inline bool mapping_unmovable(struct address_space *mapping)
324 {
325 return test_bit(AS_UNMOVABLE, &mapping->flags);
326 }
327
mapping_gfp_mask(struct address_space * mapping)328 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
329 {
330 return mapping->gfp_mask;
331 }
332
333 /* Restricts the given gfp_mask to what the mapping allows. */
mapping_gfp_constraint(struct address_space * mapping,gfp_t gfp_mask)334 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping,
335 gfp_t gfp_mask)
336 {
337 return mapping_gfp_mask(mapping) & gfp_mask;
338 }
339
340 /*
341 * This is non-atomic. Only to be used before the mapping is activated.
342 * Probably needs a barrier...
343 */
mapping_set_gfp_mask(struct address_space * m,gfp_t mask)344 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
345 {
346 m->gfp_mask = mask;
347 }
348
349 /**
350 * mapping_set_large_folios() - Indicate the file supports large folios.
351 * @mapping: The file.
352 *
353 * The filesystem should call this function in its inode constructor to
354 * indicate that the VFS can use large folios to cache the contents of
355 * the file.
356 *
357 * Context: This should not be called while the inode is active as it
358 * is non-atomic.
359 */
mapping_set_large_folios(struct address_space * mapping)360 static inline void mapping_set_large_folios(struct address_space *mapping)
361 {
362 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
363 }
364
365 /*
366 * Large folio support currently depends on THP. These dependencies are
367 * being worked on but are not yet fixed.
368 */
mapping_large_folio_support(struct address_space * mapping)369 static inline bool mapping_large_folio_support(struct address_space *mapping)
370 {
371 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
372 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
373 }
374
filemap_nr_thps(struct address_space * mapping)375 static inline int filemap_nr_thps(struct address_space *mapping)
376 {
377 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
378 return atomic_read(&mapping->nr_thps);
379 #else
380 return 0;
381 #endif
382 }
383
filemap_nr_thps_inc(struct address_space * mapping)384 static inline void filemap_nr_thps_inc(struct address_space *mapping)
385 {
386 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
387 if (!mapping_large_folio_support(mapping))
388 atomic_inc(&mapping->nr_thps);
389 #else
390 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
391 #endif
392 }
393
filemap_nr_thps_dec(struct address_space * mapping)394 static inline void filemap_nr_thps_dec(struct address_space *mapping)
395 {
396 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
397 if (!mapping_large_folio_support(mapping))
398 atomic_dec(&mapping->nr_thps);
399 #else
400 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0);
401 #endif
402 }
403
404 struct address_space *page_mapping(struct page *);
405 struct address_space *folio_mapping(struct folio *);
406 struct address_space *swapcache_mapping(struct folio *);
407
408 /**
409 * folio_file_mapping - Find the mapping this folio belongs to.
410 * @folio: The folio.
411 *
412 * For folios which are in the page cache, return the mapping that this
413 * page belongs to. Folios in the swap cache return the mapping of the
414 * swap file or swap device where the data is stored. This is different
415 * from the mapping returned by folio_mapping(). The only reason to
416 * use it is if, like NFS, you return 0 from ->activate_swapfile.
417 *
418 * Do not call this for folios which aren't in the page cache or swap cache.
419 */
folio_file_mapping(struct folio * folio)420 static inline struct address_space *folio_file_mapping(struct folio *folio)
421 {
422 if (unlikely(folio_test_swapcache(folio)))
423 return swapcache_mapping(folio);
424
425 return folio->mapping;
426 }
427
428 /**
429 * folio_flush_mapping - Find the file mapping this folio belongs to.
430 * @folio: The folio.
431 *
432 * For folios which are in the page cache, return the mapping that this
433 * page belongs to. Anonymous folios return NULL, even if they're in
434 * the swap cache. Other kinds of folio also return NULL.
435 *
436 * This is ONLY used by architecture cache flushing code. If you aren't
437 * writing cache flushing code, you want either folio_mapping() or
438 * folio_file_mapping().
439 */
folio_flush_mapping(struct folio * folio)440 static inline struct address_space *folio_flush_mapping(struct folio *folio)
441 {
442 if (unlikely(folio_test_swapcache(folio)))
443 return NULL;
444
445 return folio_mapping(folio);
446 }
447
page_file_mapping(struct page * page)448 static inline struct address_space *page_file_mapping(struct page *page)
449 {
450 return folio_file_mapping(page_folio(page));
451 }
452
453 /**
454 * folio_inode - Get the host inode for this folio.
455 * @folio: The folio.
456 *
457 * For folios which are in the page cache, return the inode that this folio
458 * belongs to.
459 *
460 * Do not call this for folios which aren't in the page cache.
461 */
folio_inode(struct folio * folio)462 static inline struct inode *folio_inode(struct folio *folio)
463 {
464 return folio->mapping->host;
465 }
466
467 /**
468 * folio_attach_private - Attach private data to a folio.
469 * @folio: Folio to attach data to.
470 * @data: Data to attach to folio.
471 *
472 * Attaching private data to a folio increments the page's reference count.
473 * The data must be detached before the folio will be freed.
474 */
folio_attach_private(struct folio * folio,void * data)475 static inline void folio_attach_private(struct folio *folio, void *data)
476 {
477 folio_get(folio);
478 folio->private = data;
479 folio_set_private(folio);
480 }
481
482 /**
483 * folio_change_private - Change private data on a folio.
484 * @folio: Folio to change the data on.
485 * @data: Data to set on the folio.
486 *
487 * Change the private data attached to a folio and return the old
488 * data. The page must previously have had data attached and the data
489 * must be detached before the folio will be freed.
490 *
491 * Return: Data that was previously attached to the folio.
492 */
folio_change_private(struct folio * folio,void * data)493 static inline void *folio_change_private(struct folio *folio, void *data)
494 {
495 void *old = folio_get_private(folio);
496
497 folio->private = data;
498 return old;
499 }
500
501 /**
502 * folio_detach_private - Detach private data from a folio.
503 * @folio: Folio to detach data from.
504 *
505 * Removes the data that was previously attached to the folio and decrements
506 * the refcount on the page.
507 *
508 * Return: Data that was attached to the folio.
509 */
folio_detach_private(struct folio * folio)510 static inline void *folio_detach_private(struct folio *folio)
511 {
512 void *data = folio_get_private(folio);
513
514 if (!folio_test_private(folio))
515 return NULL;
516 folio_clear_private(folio);
517 folio->private = NULL;
518 folio_put(folio);
519
520 return data;
521 }
522
attach_page_private(struct page * page,void * data)523 static inline void attach_page_private(struct page *page, void *data)
524 {
525 folio_attach_private(page_folio(page), data);
526 }
527
detach_page_private(struct page * page)528 static inline void *detach_page_private(struct page *page)
529 {
530 return folio_detach_private(page_folio(page));
531 }
532
533 /*
534 * There are some parts of the kernel which assume that PMD entries
535 * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then,
536 * limit the maximum allocation order to PMD size. I'm not aware of any
537 * assumptions about maximum order if THP are disabled, but 8 seems like
538 * a good order (that's 1MB if you're using 4kB pages)
539 */
540 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
541 #define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER
542 #else
543 #define MAX_PAGECACHE_ORDER 8
544 #endif
545
546 #ifdef CONFIG_NUMA
547 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order);
548 #else
filemap_alloc_folio(gfp_t gfp,unsigned int order)549 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
550 {
551 return folio_alloc(gfp, order);
552 }
553 #endif
554
__page_cache_alloc(gfp_t gfp)555 static inline struct page *__page_cache_alloc(gfp_t gfp)
556 {
557 return &filemap_alloc_folio(gfp, 0)->page;
558 }
559
page_cache_alloc(struct address_space * x)560 static inline struct page *page_cache_alloc(struct address_space *x)
561 {
562 return __page_cache_alloc(mapping_gfp_mask(x));
563 }
564
readahead_gfp_mask(struct address_space * x)565 static inline gfp_t readahead_gfp_mask(struct address_space *x)
566 {
567 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
568 }
569
570 typedef int filler_t(struct file *, struct folio *);
571
572 pgoff_t page_cache_next_miss(struct address_space *mapping,
573 pgoff_t index, unsigned long max_scan);
574 pgoff_t page_cache_prev_miss(struct address_space *mapping,
575 pgoff_t index, unsigned long max_scan);
576
577 /**
578 * typedef fgf_t - Flags for getting folios from the page cache.
579 *
580 * Most users of the page cache will not need to use these flags;
581 * there are convenience functions such as filemap_get_folio() and
582 * filemap_lock_folio(). For users which need more control over exactly
583 * what is done with the folios, these flags to __filemap_get_folio()
584 * are available.
585 *
586 * * %FGP_ACCESSED - The folio will be marked accessed.
587 * * %FGP_LOCK - The folio is returned locked.
588 * * %FGP_CREAT - If no folio is present then a new folio is allocated,
589 * added to the page cache and the VM's LRU list. The folio is
590 * returned locked.
591 * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
592 * folio is already in cache. If the folio was allocated, unlock it
593 * before returning so the caller can do the same dance.
594 * * %FGP_WRITE - The folio will be written to by the caller.
595 * * %FGP_NOFS - __GFP_FS will get cleared in gfp.
596 * * %FGP_NOWAIT - Don't block on the folio lock.
597 * * %FGP_STABLE - Wait for the folio to be stable (finished writeback)
598 * * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin()
599 * implementation.
600 */
601 typedef unsigned int __bitwise fgf_t;
602
603 #define FGP_ACCESSED ((__force fgf_t)0x00000001)
604 #define FGP_LOCK ((__force fgf_t)0x00000002)
605 #define FGP_CREAT ((__force fgf_t)0x00000004)
606 #define FGP_WRITE ((__force fgf_t)0x00000008)
607 #define FGP_NOFS ((__force fgf_t)0x00000010)
608 #define FGP_NOWAIT ((__force fgf_t)0x00000020)
609 #define FGP_FOR_MMAP ((__force fgf_t)0x00000040)
610 #define FGP_STABLE ((__force fgf_t)0x00000080)
611 #define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */
612
613 #define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
614
615 /**
616 * fgf_set_order - Encode a length in the fgf_t flags.
617 * @size: The suggested size of the folio to create.
618 *
619 * The caller of __filemap_get_folio() can use this to suggest a preferred
620 * size for the folio that is created. If there is already a folio at
621 * the index, it will be returned, no matter what its size. If a folio
622 * is freshly created, it may be of a different size than requested
623 * due to alignment constraints, memory pressure, or the presence of
624 * other folios at nearby indices.
625 */
fgf_set_order(size_t size)626 static inline fgf_t fgf_set_order(size_t size)
627 {
628 unsigned int shift = ilog2(size);
629
630 if (shift <= PAGE_SHIFT)
631 return 0;
632 return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
633 }
634
635 void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
636 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,
637 fgf_t fgp_flags, gfp_t gfp);
638 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
639 fgf_t fgp_flags, gfp_t gfp);
640
641 /**
642 * filemap_get_folio - Find and get a folio.
643 * @mapping: The address_space to search.
644 * @index: The page index.
645 *
646 * Looks up the page cache entry at @mapping & @index. If a folio is
647 * present, it is returned with an increased refcount.
648 *
649 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
650 * this index. Will not return a shadow, swap or DAX entry.
651 */
filemap_get_folio(struct address_space * mapping,pgoff_t index)652 static inline struct folio *filemap_get_folio(struct address_space *mapping,
653 pgoff_t index)
654 {
655 return __filemap_get_folio(mapping, index, 0, 0);
656 }
657
658 /**
659 * filemap_lock_folio - Find and lock a folio.
660 * @mapping: The address_space to search.
661 * @index: The page index.
662 *
663 * Looks up the page cache entry at @mapping & @index. If a folio is
664 * present, it is returned locked with an increased refcount.
665 *
666 * Context: May sleep.
667 * Return: A folio or ERR_PTR(-ENOENT) if there is no folio in the cache for
668 * this index. Will not return a shadow, swap or DAX entry.
669 */
filemap_lock_folio(struct address_space * mapping,pgoff_t index)670 static inline struct folio *filemap_lock_folio(struct address_space *mapping,
671 pgoff_t index)
672 {
673 return __filemap_get_folio(mapping, index, FGP_LOCK, 0);
674 }
675
676 /**
677 * filemap_grab_folio - grab a folio from the page cache
678 * @mapping: The address space to search
679 * @index: The page index
680 *
681 * Looks up the page cache entry at @mapping & @index. If no folio is found,
682 * a new folio is created. The folio is locked, marked as accessed, and
683 * returned.
684 *
685 * Return: A found or created folio. ERR_PTR(-ENOMEM) if no folio is found
686 * and failed to create a folio.
687 */
filemap_grab_folio(struct address_space * mapping,pgoff_t index)688 static inline struct folio *filemap_grab_folio(struct address_space *mapping,
689 pgoff_t index)
690 {
691 return __filemap_get_folio(mapping, index,
692 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
693 mapping_gfp_mask(mapping));
694 }
695
696 /**
697 * find_get_page - find and get a page reference
698 * @mapping: the address_space to search
699 * @offset: the page index
700 *
701 * Looks up the page cache slot at @mapping & @offset. If there is a
702 * page cache page, it is returned with an increased refcount.
703 *
704 * Otherwise, %NULL is returned.
705 */
find_get_page(struct address_space * mapping,pgoff_t offset)706 static inline struct page *find_get_page(struct address_space *mapping,
707 pgoff_t offset)
708 {
709 return pagecache_get_page(mapping, offset, 0, 0);
710 }
711
find_get_page_flags(struct address_space * mapping,pgoff_t offset,fgf_t fgp_flags)712 static inline struct page *find_get_page_flags(struct address_space *mapping,
713 pgoff_t offset, fgf_t fgp_flags)
714 {
715 return pagecache_get_page(mapping, offset, fgp_flags, 0);
716 }
717
718 /**
719 * find_lock_page - locate, pin and lock a pagecache page
720 * @mapping: the address_space to search
721 * @index: the page index
722 *
723 * Looks up the page cache entry at @mapping & @index. If there is a
724 * page cache page, it is returned locked and with an increased
725 * refcount.
726 *
727 * Context: May sleep.
728 * Return: A struct page or %NULL if there is no page in the cache for this
729 * index.
730 */
find_lock_page(struct address_space * mapping,pgoff_t index)731 static inline struct page *find_lock_page(struct address_space *mapping,
732 pgoff_t index)
733 {
734 return pagecache_get_page(mapping, index, FGP_LOCK, 0);
735 }
736
737 /**
738 * find_or_create_page - locate or add a pagecache page
739 * @mapping: the page's address_space
740 * @index: the page's index into the mapping
741 * @gfp_mask: page allocation mode
742 *
743 * Looks up the page cache slot at @mapping & @offset. If there is a
744 * page cache page, it is returned locked and with an increased
745 * refcount.
746 *
747 * If the page is not present, a new page is allocated using @gfp_mask
748 * and added to the page cache and the VM's LRU list. The page is
749 * returned locked and with an increased refcount.
750 *
751 * On memory exhaustion, %NULL is returned.
752 *
753 * find_or_create_page() may sleep, even if @gfp_flags specifies an
754 * atomic allocation!
755 */
find_or_create_page(struct address_space * mapping,pgoff_t index,gfp_t gfp_mask)756 static inline struct page *find_or_create_page(struct address_space *mapping,
757 pgoff_t index, gfp_t gfp_mask)
758 {
759 return pagecache_get_page(mapping, index,
760 FGP_LOCK|FGP_ACCESSED|FGP_CREAT,
761 gfp_mask);
762 }
763
764 /**
765 * grab_cache_page_nowait - returns locked page at given index in given cache
766 * @mapping: target address_space
767 * @index: the page index
768 *
769 * Same as grab_cache_page(), but do not wait if the page is unavailable.
770 * This is intended for speculative data generators, where the data can
771 * be regenerated if the page couldn't be grabbed. This routine should
772 * be safe to call while holding the lock for another page.
773 *
774 * Clear __GFP_FS when allocating the page to avoid recursion into the fs
775 * and deadlock against the caller's locked page.
776 */
grab_cache_page_nowait(struct address_space * mapping,pgoff_t index)777 static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
778 pgoff_t index)
779 {
780 return pagecache_get_page(mapping, index,
781 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
782 mapping_gfp_mask(mapping));
783 }
784
785 #define swapcache_index(folio) __page_file_index(&(folio)->page)
786
787 /**
788 * folio_index - File index of a folio.
789 * @folio: The folio.
790 *
791 * For a folio which is either in the page cache or the swap cache,
792 * return its index within the address_space it belongs to. If you know
793 * the page is definitely in the page cache, you can look at the folio's
794 * index directly.
795 *
796 * Return: The index (offset in units of pages) of a folio in its file.
797 */
folio_index(struct folio * folio)798 static inline pgoff_t folio_index(struct folio *folio)
799 {
800 if (unlikely(folio_test_swapcache(folio)))
801 return swapcache_index(folio);
802 return folio->index;
803 }
804
805 /**
806 * folio_next_index - Get the index of the next folio.
807 * @folio: The current folio.
808 *
809 * Return: The index of the folio which follows this folio in the file.
810 */
folio_next_index(struct folio * folio)811 static inline pgoff_t folio_next_index(struct folio *folio)
812 {
813 return folio->index + folio_nr_pages(folio);
814 }
815
816 /**
817 * folio_file_page - The page for a particular index.
818 * @folio: The folio which contains this index.
819 * @index: The index we want to look up.
820 *
821 * Sometimes after looking up a folio in the page cache, we need to
822 * obtain the specific page for an index (eg a page fault).
823 *
824 * Return: The page containing the file data for this index.
825 */
folio_file_page(struct folio * folio,pgoff_t index)826 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
827 {
828 return folio_page(folio, index & (folio_nr_pages(folio) - 1));
829 }
830
831 /**
832 * folio_contains - Does this folio contain this index?
833 * @folio: The folio.
834 * @index: The page index within the file.
835 *
836 * Context: The caller should have the page locked in order to prevent
837 * (eg) shmem from moving the page between the page cache and swap cache
838 * and changing its index in the middle of the operation.
839 * Return: true or false.
840 */
folio_contains(struct folio * folio,pgoff_t index)841 static inline bool folio_contains(struct folio *folio, pgoff_t index)
842 {
843 return index - folio_index(folio) < folio_nr_pages(folio);
844 }
845
846 /*
847 * Given the page we found in the page cache, return the page corresponding
848 * to this index in the file
849 */
find_subpage(struct page * head,pgoff_t index)850 static inline struct page *find_subpage(struct page *head, pgoff_t index)
851 {
852 /* HugeTLBfs wants the head page regardless */
853 if (PageHuge(head))
854 return head;
855
856 return head + (index & (thp_nr_pages(head) - 1));
857 }
858
859 unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
860 pgoff_t end, struct folio_batch *fbatch);
861 unsigned filemap_get_folios_contig(struct address_space *mapping,
862 pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
863 unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start,
864 pgoff_t end, xa_mark_t tag, struct folio_batch *fbatch);
865
866 struct page *grab_cache_page_write_begin(struct address_space *mapping,
867 pgoff_t index);
868
869 /*
870 * Returns locked page at given index in given cache, creating it if needed.
871 */
grab_cache_page(struct address_space * mapping,pgoff_t index)872 static inline struct page *grab_cache_page(struct address_space *mapping,
873 pgoff_t index)
874 {
875 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
876 }
877
878 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
879 filler_t *filler, struct file *file);
880 struct folio *mapping_read_folio_gfp(struct address_space *, pgoff_t index,
881 gfp_t flags);
882 struct page *read_cache_page(struct address_space *, pgoff_t index,
883 filler_t *filler, struct file *file);
884 extern struct page * read_cache_page_gfp(struct address_space *mapping,
885 pgoff_t index, gfp_t gfp_mask);
886
read_mapping_page(struct address_space * mapping,pgoff_t index,struct file * file)887 static inline struct page *read_mapping_page(struct address_space *mapping,
888 pgoff_t index, struct file *file)
889 {
890 return read_cache_page(mapping, index, NULL, file);
891 }
892
read_mapping_folio(struct address_space * mapping,pgoff_t index,struct file * file)893 static inline struct folio *read_mapping_folio(struct address_space *mapping,
894 pgoff_t index, struct file *file)
895 {
896 return read_cache_folio(mapping, index, NULL, file);
897 }
898
899 /*
900 * Get the offset in PAGE_SIZE (even for hugetlb pages).
901 */
page_to_pgoff(struct page * page)902 static inline pgoff_t page_to_pgoff(struct page *page)
903 {
904 struct page *head;
905
906 if (likely(!PageTransTail(page)))
907 return page->index;
908
909 head = compound_head(page);
910 /*
911 * We don't initialize ->index for tail pages: calculate based on
912 * head page
913 */
914 return head->index + page - head;
915 }
916
917 /*
918 * Return byte-offset into filesystem object for page.
919 */
page_offset(struct page * page)920 static inline loff_t page_offset(struct page *page)
921 {
922 return ((loff_t)page->index) << PAGE_SHIFT;
923 }
924
page_file_offset(struct page * page)925 static inline loff_t page_file_offset(struct page *page)
926 {
927 return ((loff_t)page_index(page)) << PAGE_SHIFT;
928 }
929
930 /**
931 * folio_pos - Returns the byte position of this folio in its file.
932 * @folio: The folio.
933 */
folio_pos(struct folio * folio)934 static inline loff_t folio_pos(struct folio *folio)
935 {
936 return page_offset(&folio->page);
937 }
938
939 /**
940 * folio_file_pos - Returns the byte position of this folio in its file.
941 * @folio: The folio.
942 *
943 * This differs from folio_pos() for folios which belong to a swap file.
944 * NFS is the only filesystem today which needs to use folio_file_pos().
945 */
folio_file_pos(struct folio * folio)946 static inline loff_t folio_file_pos(struct folio *folio)
947 {
948 return page_file_offset(&folio->page);
949 }
950
951 /*
952 * Get the offset in PAGE_SIZE (even for hugetlb folios).
953 */
folio_pgoff(struct folio * folio)954 static inline pgoff_t folio_pgoff(struct folio *folio)
955 {
956 return folio->index;
957 }
958
linear_page_index(struct vm_area_struct * vma,unsigned long address)959 static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
960 unsigned long address)
961 {
962 pgoff_t pgoff;
963 pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
964 pgoff += vma->vm_pgoff;
965 return pgoff;
966 }
967
968 struct wait_page_key {
969 struct folio *folio;
970 int bit_nr;
971 int page_match;
972 };
973
974 struct wait_page_queue {
975 struct folio *folio;
976 int bit_nr;
977 wait_queue_entry_t wait;
978 };
979
wake_page_match(struct wait_page_queue * wait_page,struct wait_page_key * key)980 static inline bool wake_page_match(struct wait_page_queue *wait_page,
981 struct wait_page_key *key)
982 {
983 if (wait_page->folio != key->folio)
984 return false;
985 key->page_match = 1;
986
987 if (wait_page->bit_nr != key->bit_nr)
988 return false;
989
990 return true;
991 }
992
993 void __folio_lock(struct folio *folio);
994 int __folio_lock_killable(struct folio *folio);
995 vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf);
996 void unlock_page(struct page *page);
997 void folio_unlock(struct folio *folio);
998
999 /**
1000 * folio_trylock() - Attempt to lock a folio.
1001 * @folio: The folio to attempt to lock.
1002 *
1003 * Sometimes it is undesirable to wait for a folio to be unlocked (eg
1004 * when the locks are being taken in the wrong order, or if making
1005 * progress through a batch of folios is more important than processing
1006 * them in order). Usually folio_lock() is the correct function to call.
1007 *
1008 * Context: Any context.
1009 * Return: Whether the lock was successfully acquired.
1010 */
folio_trylock(struct folio * folio)1011 static inline bool folio_trylock(struct folio *folio)
1012 {
1013 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
1014 }
1015
1016 /*
1017 * Return true if the page was successfully locked
1018 */
trylock_page(struct page * page)1019 static inline int trylock_page(struct page *page)
1020 {
1021 return folio_trylock(page_folio(page));
1022 }
1023
1024 /**
1025 * folio_lock() - Lock this folio.
1026 * @folio: The folio to lock.
1027 *
1028 * The folio lock protects against many things, probably more than it
1029 * should. It is primarily held while a folio is being brought uptodate,
1030 * either from its backing file or from swap. It is also held while a
1031 * folio is being truncated from its address_space, so holding the lock
1032 * is sufficient to keep folio->mapping stable.
1033 *
1034 * The folio lock is also held while write() is modifying the page to
1035 * provide POSIX atomicity guarantees (as long as the write does not
1036 * cross a page boundary). Other modifications to the data in the folio
1037 * do not hold the folio lock and can race with writes, eg DMA and stores
1038 * to mapped pages.
1039 *
1040 * Context: May sleep. If you need to acquire the locks of two or
1041 * more folios, they must be in order of ascending index, if they are
1042 * in the same address_space. If they are in different address_spaces,
1043 * acquire the lock of the folio which belongs to the address_space which
1044 * has the lowest address in memory first.
1045 */
folio_lock(struct folio * folio)1046 static inline void folio_lock(struct folio *folio)
1047 {
1048 might_sleep();
1049 if (!folio_trylock(folio))
1050 __folio_lock(folio);
1051 }
1052
1053 /**
1054 * lock_page() - Lock the folio containing this page.
1055 * @page: The page to lock.
1056 *
1057 * See folio_lock() for a description of what the lock protects.
1058 * This is a legacy function and new code should probably use folio_lock()
1059 * instead.
1060 *
1061 * Context: May sleep. Pages in the same folio share a lock, so do not
1062 * attempt to lock two pages which share a folio.
1063 */
lock_page(struct page * page)1064 static inline void lock_page(struct page *page)
1065 {
1066 struct folio *folio;
1067 might_sleep();
1068
1069 folio = page_folio(page);
1070 if (!folio_trylock(folio))
1071 __folio_lock(folio);
1072 }
1073
1074 /**
1075 * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
1076 * @folio: The folio to lock.
1077 *
1078 * Attempts to lock the folio, like folio_lock(), except that the sleep
1079 * to acquire the lock is interruptible by a fatal signal.
1080 *
1081 * Context: May sleep; see folio_lock().
1082 * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
1083 */
folio_lock_killable(struct folio * folio)1084 static inline int folio_lock_killable(struct folio *folio)
1085 {
1086 might_sleep();
1087 if (!folio_trylock(folio))
1088 return __folio_lock_killable(folio);
1089 return 0;
1090 }
1091
1092 /*
1093 * folio_lock_or_retry - Lock the folio, unless this would block and the
1094 * caller indicated that it can handle a retry.
1095 *
1096 * Return value and mmap_lock implications depend on flags; see
1097 * __folio_lock_or_retry().
1098 */
folio_lock_or_retry(struct folio * folio,struct vm_fault * vmf)1099 static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
1100 struct vm_fault *vmf)
1101 {
1102 might_sleep();
1103 if (!folio_trylock(folio))
1104 return __folio_lock_or_retry(folio, vmf);
1105 return 0;
1106 }
1107
1108 /*
1109 * This is exported only for folio_wait_locked/folio_wait_writeback, etc.,
1110 * and should not be used directly.
1111 */
1112 void folio_wait_bit(struct folio *folio, int bit_nr);
1113 int folio_wait_bit_killable(struct folio *folio, int bit_nr);
1114
1115 /*
1116 * Wait for a folio to be unlocked.
1117 *
1118 * This must be called with the caller "holding" the folio,
1119 * ie with increased folio reference count so that the folio won't
1120 * go away during the wait.
1121 */
folio_wait_locked(struct folio * folio)1122 static inline void folio_wait_locked(struct folio *folio)
1123 {
1124 if (folio_test_locked(folio))
1125 folio_wait_bit(folio, PG_locked);
1126 }
1127
folio_wait_locked_killable(struct folio * folio)1128 static inline int folio_wait_locked_killable(struct folio *folio)
1129 {
1130 if (!folio_test_locked(folio))
1131 return 0;
1132 return folio_wait_bit_killable(folio, PG_locked);
1133 }
1134
wait_on_page_locked(struct page * page)1135 static inline void wait_on_page_locked(struct page *page)
1136 {
1137 folio_wait_locked(page_folio(page));
1138 }
1139
1140 void folio_end_read(struct folio *folio, bool success);
1141 void wait_on_page_writeback(struct page *page);
1142 void folio_wait_writeback(struct folio *folio);
1143 int folio_wait_writeback_killable(struct folio *folio);
1144 void end_page_writeback(struct page *page);
1145 void folio_end_writeback(struct folio *folio);
1146 void wait_for_stable_page(struct page *page);
1147 void folio_wait_stable(struct folio *folio);
1148 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
__set_page_dirty(struct page * page,struct address_space * mapping,int warn)1149 static inline void __set_page_dirty(struct page *page,
1150 struct address_space *mapping, int warn)
1151 {
1152 __folio_mark_dirty(page_folio(page), mapping, warn);
1153 }
1154 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
1155 void __folio_cancel_dirty(struct folio *folio);
folio_cancel_dirty(struct folio * folio)1156 static inline void folio_cancel_dirty(struct folio *folio)
1157 {
1158 /* Avoid atomic ops, locking, etc. when not actually needed. */
1159 if (folio_test_dirty(folio))
1160 __folio_cancel_dirty(folio);
1161 }
1162 bool folio_clear_dirty_for_io(struct folio *folio);
1163 bool clear_page_dirty_for_io(struct page *page);
1164 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
1165 int __set_page_dirty_nobuffers(struct page *page);
1166 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
1167
1168 #ifdef CONFIG_MIGRATION
1169 int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
1170 struct folio *src, enum migrate_mode mode);
1171 #else
1172 #define filemap_migrate_folio NULL
1173 #endif
1174 void folio_end_private_2(struct folio *folio);
1175 void folio_wait_private_2(struct folio *folio);
1176 int folio_wait_private_2_killable(struct folio *folio);
1177
1178 /*
1179 * Add an arbitrary waiter to a page's wait queue
1180 */
1181 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter);
1182
1183 /*
1184 * Fault in userspace address range.
1185 */
1186 size_t fault_in_writeable(char __user *uaddr, size_t size);
1187 size_t fault_in_subpage_writeable(char __user *uaddr, size_t size);
1188 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size);
1189 size_t fault_in_readable(const char __user *uaddr, size_t size);
1190
1191 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
1192 pgoff_t index, gfp_t gfp);
1193 int filemap_add_folio(struct address_space *mapping, struct folio *folio,
1194 pgoff_t index, gfp_t gfp);
1195 void filemap_remove_folio(struct folio *folio);
1196 void __filemap_remove_folio(struct folio *folio, void *shadow);
1197 void replace_page_cache_folio(struct folio *old, struct folio *new);
1198 void delete_from_page_cache_batch(struct address_space *mapping,
1199 struct folio_batch *fbatch);
1200 bool filemap_release_folio(struct folio *folio, gfp_t gfp);
1201 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end,
1202 int whence);
1203
1204 /* Must be non-static for BPF error injection */
1205 int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
1206 pgoff_t index, gfp_t gfp, void **shadowp);
1207
1208 bool filemap_range_has_writeback(struct address_space *mapping,
1209 loff_t start_byte, loff_t end_byte);
1210
1211 /**
1212 * filemap_range_needs_writeback - check if range potentially needs writeback
1213 * @mapping: address space within which to check
1214 * @start_byte: offset in bytes where the range starts
1215 * @end_byte: offset in bytes where the range ends (inclusive)
1216 *
1217 * Find at least one page in the range supplied, usually used to check if
1218 * direct writing in this range will trigger a writeback. Used by O_DIRECT
1219 * read/write with IOCB_NOWAIT, to see if the caller needs to do
1220 * filemap_write_and_wait_range() before proceeding.
1221 *
1222 * Return: %true if the caller should do filemap_write_and_wait_range() before
1223 * doing O_DIRECT to a page in this range, %false otherwise.
1224 */
filemap_range_needs_writeback(struct address_space * mapping,loff_t start_byte,loff_t end_byte)1225 static inline bool filemap_range_needs_writeback(struct address_space *mapping,
1226 loff_t start_byte,
1227 loff_t end_byte)
1228 {
1229 if (!mapping->nrpages)
1230 return false;
1231 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
1232 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
1233 return false;
1234 return filemap_range_has_writeback(mapping, start_byte, end_byte);
1235 }
1236
1237 /**
1238 * struct readahead_control - Describes a readahead request.
1239 *
1240 * A readahead request is for consecutive pages. Filesystems which
1241 * implement the ->readahead method should call readahead_page() or
1242 * readahead_page_batch() in a loop and attempt to start I/O against
1243 * each page in the request.
1244 *
1245 * Most of the fields in this struct are private and should be accessed
1246 * by the functions below.
1247 *
1248 * @file: The file, used primarily by network filesystems for authentication.
1249 * May be NULL if invoked internally by the filesystem.
1250 * @mapping: Readahead this filesystem object.
1251 * @ra: File readahead state. May be NULL.
1252 */
1253 struct readahead_control {
1254 struct file *file;
1255 struct address_space *mapping;
1256 struct file_ra_state *ra;
1257 /* private: use the readahead_* accessors instead */
1258 pgoff_t _index;
1259 unsigned int _nr_pages;
1260 unsigned int _batch_count;
1261 bool _workingset;
1262 unsigned long _pflags;
1263 };
1264
1265 #define DEFINE_READAHEAD(ractl, f, r, m, i) \
1266 struct readahead_control ractl = { \
1267 .file = f, \
1268 .mapping = m, \
1269 .ra = r, \
1270 ._index = i, \
1271 }
1272
1273 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)
1274
1275 void page_cache_ra_unbounded(struct readahead_control *,
1276 unsigned long nr_to_read, unsigned long lookahead_count);
1277 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
1278 void page_cache_async_ra(struct readahead_control *, struct folio *,
1279 unsigned long req_count);
1280 void readahead_expand(struct readahead_control *ractl,
1281 loff_t new_start, size_t new_len);
1282
1283 /**
1284 * page_cache_sync_readahead - generic file readahead
1285 * @mapping: address_space which holds the pagecache and I/O vectors
1286 * @ra: file_ra_state which holds the readahead state
1287 * @file: Used by the filesystem for authentication.
1288 * @index: Index of first page to be read.
1289 * @req_count: Total number of pages being read by the caller.
1290 *
1291 * page_cache_sync_readahead() should be called when a cache miss happened:
1292 * it will submit the read. The readahead logic may decide to piggyback more
1293 * pages onto the read request if access patterns suggest it will improve
1294 * performance.
1295 */
1296 static inline
page_cache_sync_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,pgoff_t index,unsigned long req_count)1297 void page_cache_sync_readahead(struct address_space *mapping,
1298 struct file_ra_state *ra, struct file *file, pgoff_t index,
1299 unsigned long req_count)
1300 {
1301 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1302 page_cache_sync_ra(&ractl, req_count);
1303 }
1304
1305 /**
1306 * page_cache_async_readahead - file readahead for marked pages
1307 * @mapping: address_space which holds the pagecache and I/O vectors
1308 * @ra: file_ra_state which holds the readahead state
1309 * @file: Used by the filesystem for authentication.
1310 * @folio: The folio at @index which triggered the readahead call.
1311 * @index: Index of first page to be read.
1312 * @req_count: Total number of pages being read by the caller.
1313 *
1314 * page_cache_async_readahead() should be called when a page is used which
1315 * is marked as PageReadahead; this is a marker to suggest that the application
1316 * has used up enough of the readahead window that we should start pulling in
1317 * more pages.
1318 */
1319 static inline
page_cache_async_readahead(struct address_space * mapping,struct file_ra_state * ra,struct file * file,struct folio * folio,pgoff_t index,unsigned long req_count)1320 void page_cache_async_readahead(struct address_space *mapping,
1321 struct file_ra_state *ra, struct file *file,
1322 struct folio *folio, pgoff_t index, unsigned long req_count)
1323 {
1324 DEFINE_READAHEAD(ractl, file, ra, mapping, index);
1325 page_cache_async_ra(&ractl, folio, req_count);
1326 }
1327
__readahead_folio(struct readahead_control * ractl)1328 static inline struct folio *__readahead_folio(struct readahead_control *ractl)
1329 {
1330 struct folio *folio;
1331
1332 BUG_ON(ractl->_batch_count > ractl->_nr_pages);
1333 ractl->_nr_pages -= ractl->_batch_count;
1334 ractl->_index += ractl->_batch_count;
1335
1336 if (!ractl->_nr_pages) {
1337 ractl->_batch_count = 0;
1338 return NULL;
1339 }
1340
1341 folio = xa_load(&ractl->mapping->i_pages, ractl->_index);
1342 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
1343 ractl->_batch_count = folio_nr_pages(folio);
1344
1345 return folio;
1346 }
1347
1348 /**
1349 * readahead_page - Get the next page to read.
1350 * @ractl: The current readahead request.
1351 *
1352 * Context: The page is locked and has an elevated refcount. The caller
1353 * should decreases the refcount once the page has been submitted for I/O
1354 * and unlock the page once all I/O to that page has completed.
1355 * Return: A pointer to the next page, or %NULL if we are done.
1356 */
readahead_page(struct readahead_control * ractl)1357 static inline struct page *readahead_page(struct readahead_control *ractl)
1358 {
1359 struct folio *folio = __readahead_folio(ractl);
1360
1361 return &folio->page;
1362 }
1363
1364 /**
1365 * readahead_folio - Get the next folio to read.
1366 * @ractl: The current readahead request.
1367 *
1368 * Context: The folio is locked. The caller should unlock the folio once
1369 * all I/O to that folio has completed.
1370 * Return: A pointer to the next folio, or %NULL if we are done.
1371 */
readahead_folio(struct readahead_control * ractl)1372 static inline struct folio *readahead_folio(struct readahead_control *ractl)
1373 {
1374 struct folio *folio = __readahead_folio(ractl);
1375
1376 if (folio)
1377 folio_put(folio);
1378 return folio;
1379 }
1380
__readahead_batch(struct readahead_control * rac,struct page ** array,unsigned int array_sz)1381 static inline unsigned int __readahead_batch(struct readahead_control *rac,
1382 struct page **array, unsigned int array_sz)
1383 {
1384 unsigned int i = 0;
1385 XA_STATE(xas, &rac->mapping->i_pages, 0);
1386 struct page *page;
1387
1388 BUG_ON(rac->_batch_count > rac->_nr_pages);
1389 rac->_nr_pages -= rac->_batch_count;
1390 rac->_index += rac->_batch_count;
1391 rac->_batch_count = 0;
1392
1393 xas_set(&xas, rac->_index);
1394 rcu_read_lock();
1395 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
1396 if (xas_retry(&xas, page))
1397 continue;
1398 VM_BUG_ON_PAGE(!PageLocked(page), page);
1399 VM_BUG_ON_PAGE(PageTail(page), page);
1400 array[i++] = page;
1401 rac->_batch_count += thp_nr_pages(page);
1402 if (i == array_sz)
1403 break;
1404 }
1405 rcu_read_unlock();
1406
1407 return i;
1408 }
1409
1410 /**
1411 * readahead_page_batch - Get a batch of pages to read.
1412 * @rac: The current readahead request.
1413 * @array: An array of pointers to struct page.
1414 *
1415 * Context: The pages are locked and have an elevated refcount. The caller
1416 * should decreases the refcount once the page has been submitted for I/O
1417 * and unlock the page once all I/O to that page has completed.
1418 * Return: The number of pages placed in the array. 0 indicates the request
1419 * is complete.
1420 */
1421 #define readahead_page_batch(rac, array) \
1422 __readahead_batch(rac, array, ARRAY_SIZE(array))
1423
1424 /**
1425 * readahead_pos - The byte offset into the file of this readahead request.
1426 * @rac: The readahead request.
1427 */
readahead_pos(struct readahead_control * rac)1428 static inline loff_t readahead_pos(struct readahead_control *rac)
1429 {
1430 return (loff_t)rac->_index * PAGE_SIZE;
1431 }
1432
1433 /**
1434 * readahead_length - The number of bytes in this readahead request.
1435 * @rac: The readahead request.
1436 */
readahead_length(struct readahead_control * rac)1437 static inline size_t readahead_length(struct readahead_control *rac)
1438 {
1439 return rac->_nr_pages * PAGE_SIZE;
1440 }
1441
1442 /**
1443 * readahead_index - The index of the first page in this readahead request.
1444 * @rac: The readahead request.
1445 */
readahead_index(struct readahead_control * rac)1446 static inline pgoff_t readahead_index(struct readahead_control *rac)
1447 {
1448 return rac->_index;
1449 }
1450
1451 /**
1452 * readahead_count - The number of pages in this readahead request.
1453 * @rac: The readahead request.
1454 */
readahead_count(struct readahead_control * rac)1455 static inline unsigned int readahead_count(struct readahead_control *rac)
1456 {
1457 return rac->_nr_pages;
1458 }
1459
1460 /**
1461 * readahead_batch_length - The number of bytes in the current batch.
1462 * @rac: The readahead request.
1463 */
readahead_batch_length(struct readahead_control * rac)1464 static inline size_t readahead_batch_length(struct readahead_control *rac)
1465 {
1466 return rac->_batch_count * PAGE_SIZE;
1467 }
1468
dir_pages(struct inode * inode)1469 static inline unsigned long dir_pages(struct inode *inode)
1470 {
1471 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >>
1472 PAGE_SHIFT;
1473 }
1474
1475 /**
1476 * folio_mkwrite_check_truncate - check if folio was truncated
1477 * @folio: the folio to check
1478 * @inode: the inode to check the folio against
1479 *
1480 * Return: the number of bytes in the folio up to EOF,
1481 * or -EFAULT if the folio was truncated.
1482 */
folio_mkwrite_check_truncate(struct folio * folio,struct inode * inode)1483 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio,
1484 struct inode *inode)
1485 {
1486 loff_t size = i_size_read(inode);
1487 pgoff_t index = size >> PAGE_SHIFT;
1488 size_t offset = offset_in_folio(folio, size);
1489
1490 if (!folio->mapping)
1491 return -EFAULT;
1492
1493 /* folio is wholly inside EOF */
1494 if (folio_next_index(folio) - 1 < index)
1495 return folio_size(folio);
1496 /* folio is wholly past EOF */
1497 if (folio->index > index || !offset)
1498 return -EFAULT;
1499 /* folio is partially inside EOF */
1500 return offset;
1501 }
1502
1503 /**
1504 * page_mkwrite_check_truncate - check if page was truncated
1505 * @page: the page to check
1506 * @inode: the inode to check the page against
1507 *
1508 * Returns the number of bytes in the page up to EOF,
1509 * or -EFAULT if the page was truncated.
1510 */
page_mkwrite_check_truncate(struct page * page,struct inode * inode)1511 static inline int page_mkwrite_check_truncate(struct page *page,
1512 struct inode *inode)
1513 {
1514 loff_t size = i_size_read(inode);
1515 pgoff_t index = size >> PAGE_SHIFT;
1516 int offset = offset_in_page(size);
1517
1518 if (page->mapping != inode->i_mapping)
1519 return -EFAULT;
1520
1521 /* page is wholly inside EOF */
1522 if (page->index < index)
1523 return PAGE_SIZE;
1524 /* page is wholly past EOF */
1525 if (page->index > index || !offset)
1526 return -EFAULT;
1527 /* page is partially inside EOF */
1528 return offset;
1529 }
1530
1531 /**
1532 * i_blocks_per_folio - How many blocks fit in this folio.
1533 * @inode: The inode which contains the blocks.
1534 * @folio: The folio.
1535 *
1536 * If the block size is larger than the size of this folio, return zero.
1537 *
1538 * Context: The caller should hold a refcount on the folio to prevent it
1539 * from being split.
1540 * Return: The number of filesystem blocks covered by this folio.
1541 */
1542 static inline
i_blocks_per_folio(struct inode * inode,struct folio * folio)1543 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio)
1544 {
1545 return folio_size(folio) >> inode->i_blkbits;
1546 }
1547
1548 static inline
i_blocks_per_page(struct inode * inode,struct page * page)1549 unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
1550 {
1551 return i_blocks_per_folio(inode, page_folio(page));
1552 }
1553 #endif /* _LINUX_PAGEMAP_H */
1554