xref: /dragonfly/sys/kern/vfs_aio.c (revision fe76c4fb)
1 /*
2  * Copyright (c) 1997 John S. Dyson.  All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. John S. Dyson's name may not be used to endorse or promote products
10  *    derived from this software without specific prior written permission.
11  *
12  * DISCLAIMER:  This code isn't warranted to do anything useful.  Anything
13  * bad that happens because of using this software isn't the responsibility
14  * of the author.  This software is distributed AS-IS.
15  *
16  * $FreeBSD: src/sys/kern/vfs_aio.c,v 1.70.2.28 2003/05/29 06:15:35 alc Exp $
17  * $DragonFly: src/sys/kern/vfs_aio.c,v 1.29 2006/06/13 08:12:03 dillon Exp $
18  */
19 
20 /*
21  * This file contains support for the POSIX 1003.1B AIO/LIO facility.
22  */
23 
24 #include <sys/param.h>
25 #include <sys/systm.h>
26 #include <sys/buf.h>
27 #include <sys/sysproto.h>
28 #include <sys/filedesc.h>
29 #include <sys/kernel.h>
30 #include <sys/fcntl.h>
31 #include <sys/file.h>
32 #include <sys/lock.h>
33 #include <sys/unistd.h>
34 #include <sys/proc.h>
35 #include <sys/resourcevar.h>
36 #include <sys/signalvar.h>
37 #include <sys/protosw.h>
38 #include <sys/socketvar.h>
39 #include <sys/sysctl.h>
40 #include <sys/vnode.h>
41 #include <sys/conf.h>
42 #include <sys/event.h>
43 
44 #include <vm/vm.h>
45 #include <vm/vm_extern.h>
46 #include <vm/pmap.h>
47 #include <vm/vm_map.h>
48 #include <vm/vm_zone.h>
49 #include <sys/aio.h>
50 #include <sys/file2.h>
51 #include <sys/buf2.h>
52 #include <sys/thread2.h>
53 
54 #include <machine/limits.h>
55 #include "opt_vfs_aio.h"
56 
57 #ifdef VFS_AIO
58 
59 /*
60  * Counter for allocating reference ids to new jobs.  Wrapped to 1 on
61  * overflow.
62  */
63 static	long jobrefid;
64 
65 #define JOBST_NULL		0x0
66 #define JOBST_JOBQGLOBAL	0x2
67 #define JOBST_JOBRUNNING	0x3
68 #define JOBST_JOBFINISHED	0x4
69 #define	JOBST_JOBQBUF		0x5
70 #define	JOBST_JOBBFINISHED	0x6
71 
72 #ifndef MAX_AIO_PER_PROC
73 #define MAX_AIO_PER_PROC	32
74 #endif
75 
76 #ifndef MAX_AIO_QUEUE_PER_PROC
77 #define MAX_AIO_QUEUE_PER_PROC	256 /* Bigger than AIO_LISTIO_MAX */
78 #endif
79 
80 #ifndef MAX_AIO_PROCS
81 #define MAX_AIO_PROCS		32
82 #endif
83 
84 #ifndef MAX_AIO_QUEUE
85 #define	MAX_AIO_QUEUE		1024 /* Bigger than AIO_LISTIO_MAX */
86 #endif
87 
88 #ifndef TARGET_AIO_PROCS
89 #define TARGET_AIO_PROCS	4
90 #endif
91 
92 #ifndef MAX_BUF_AIO
93 #define MAX_BUF_AIO		16
94 #endif
95 
96 #ifndef AIOD_TIMEOUT_DEFAULT
97 #define	AIOD_TIMEOUT_DEFAULT	(10 * hz)
98 #endif
99 
100 #ifndef AIOD_LIFETIME_DEFAULT
101 #define AIOD_LIFETIME_DEFAULT	(30 * hz)
102 #endif
103 
104 SYSCTL_NODE(_vfs, OID_AUTO, aio, CTLFLAG_RW, 0, "Async IO management");
105 
106 static int max_aio_procs = MAX_AIO_PROCS;
107 SYSCTL_INT(_vfs_aio, OID_AUTO, max_aio_procs,
108 	CTLFLAG_RW, &max_aio_procs, 0,
109 	"Maximum number of kernel threads to use for handling async IO");
110 
111 static int num_aio_procs = 0;
112 SYSCTL_INT(_vfs_aio, OID_AUTO, num_aio_procs,
113 	CTLFLAG_RD, &num_aio_procs, 0,
114 	"Number of presently active kernel threads for async IO");
115 
116 /*
117  * The code will adjust the actual number of AIO processes towards this
118  * number when it gets a chance.
119  */
120 static int target_aio_procs = TARGET_AIO_PROCS;
121 SYSCTL_INT(_vfs_aio, OID_AUTO, target_aio_procs, CTLFLAG_RW, &target_aio_procs,
122 	0, "Preferred number of ready kernel threads for async IO");
123 
124 static int max_queue_count = MAX_AIO_QUEUE;
125 SYSCTL_INT(_vfs_aio, OID_AUTO, max_aio_queue, CTLFLAG_RW, &max_queue_count, 0,
126     "Maximum number of aio requests to queue, globally");
127 
128 static int num_queue_count = 0;
129 SYSCTL_INT(_vfs_aio, OID_AUTO, num_queue_count, CTLFLAG_RD, &num_queue_count, 0,
130     "Number of queued aio requests");
131 
132 static int num_buf_aio = 0;
133 SYSCTL_INT(_vfs_aio, OID_AUTO, num_buf_aio, CTLFLAG_RD, &num_buf_aio, 0,
134     "Number of aio requests presently handled by the buf subsystem");
135 
136 /* Number of async I/O thread in the process of being started */
137 /* XXX This should be local to _aio_aqueue() */
138 static int num_aio_resv_start = 0;
139 
140 static int aiod_timeout;
141 SYSCTL_INT(_vfs_aio, OID_AUTO, aiod_timeout, CTLFLAG_RW, &aiod_timeout, 0,
142     "Timeout value for synchronous aio operations");
143 
144 static int aiod_lifetime;
145 SYSCTL_INT(_vfs_aio, OID_AUTO, aiod_lifetime, CTLFLAG_RW, &aiod_lifetime, 0,
146     "Maximum lifetime for idle aiod");
147 
148 static int max_aio_per_proc = MAX_AIO_PER_PROC;
149 SYSCTL_INT(_vfs_aio, OID_AUTO, max_aio_per_proc, CTLFLAG_RW, &max_aio_per_proc,
150     0, "Maximum active aio requests per process (stored in the process)");
151 
152 static int max_aio_queue_per_proc = MAX_AIO_QUEUE_PER_PROC;
153 SYSCTL_INT(_vfs_aio, OID_AUTO, max_aio_queue_per_proc, CTLFLAG_RW,
154     &max_aio_queue_per_proc, 0,
155     "Maximum queued aio requests per process (stored in the process)");
156 
157 static int max_buf_aio = MAX_BUF_AIO;
158 SYSCTL_INT(_vfs_aio, OID_AUTO, max_buf_aio, CTLFLAG_RW, &max_buf_aio, 0,
159     "Maximum buf aio requests per process (stored in the process)");
160 
161 /*
162  * AIO process info
163  */
164 #define AIOP_FREE	0x1			/* proc on free queue */
165 #define AIOP_SCHED	0x2			/* proc explicitly scheduled */
166 
167 struct aioproclist {
168 	int aioprocflags;			/* AIO proc flags */
169 	TAILQ_ENTRY(aioproclist) list;		/* List of processes */
170 	struct proc *aioproc;			/* The AIO thread */
171 };
172 
173 /*
174  * data-structure for lio signal management
175  */
176 struct aio_liojob {
177 	int	lioj_flags;
178 	int	lioj_buffer_count;
179 	int	lioj_buffer_finished_count;
180 	int	lioj_queue_count;
181 	int	lioj_queue_finished_count;
182 	struct	sigevent lioj_signal;	/* signal on all I/O done */
183 	TAILQ_ENTRY(aio_liojob) lioj_list;
184 	struct	kaioinfo *lioj_ki;
185 };
186 #define	LIOJ_SIGNAL		0x1	/* signal on all done (lio) */
187 #define	LIOJ_SIGNAL_POSTED	0x2	/* signal has been posted */
188 
189 /*
190  * per process aio data structure
191  */
192 struct kaioinfo {
193 	int	kaio_flags;		/* per process kaio flags */
194 	int	kaio_maxactive_count;	/* maximum number of AIOs */
195 	int	kaio_active_count;	/* number of currently used AIOs */
196 	int	kaio_qallowed_count;	/* maxiumu size of AIO queue */
197 	int	kaio_queue_count;	/* size of AIO queue */
198 	int	kaio_ballowed_count;	/* maximum number of buffers */
199 	int	kaio_queue_finished_count; /* number of daemon jobs finished */
200 	int	kaio_buffer_count;	/* number of physio buffers */
201 	int	kaio_buffer_finished_count; /* count of I/O done */
202 	struct 	proc *kaio_p;		/* process that uses this kaio block */
203 	TAILQ_HEAD(,aio_liojob) kaio_liojoblist; /* list of lio jobs */
204 	TAILQ_HEAD(,aiocblist) kaio_jobqueue;	/* job queue for process */
205 	TAILQ_HEAD(,aiocblist) kaio_jobdone;	/* done queue for process */
206 	TAILQ_HEAD(,aiocblist) kaio_bufqueue;	/* buffer job queue for process */
207 	TAILQ_HEAD(,aiocblist) kaio_bufdone;	/* buffer done queue for process */
208 	TAILQ_HEAD(,aiocblist) kaio_sockqueue;	/* queue for aios waiting on sockets */
209 };
210 
211 #define KAIO_RUNDOWN	0x1	/* process is being run down */
212 #define KAIO_WAKEUP	0x2	/* wakeup process when there is a significant event */
213 
214 static TAILQ_HEAD(,aioproclist) aio_freeproc, aio_activeproc;
215 static TAILQ_HEAD(,aiocblist) aio_jobs;			/* Async job list */
216 static TAILQ_HEAD(,aiocblist) aio_bufjobs;		/* Phys I/O job list */
217 static TAILQ_HEAD(,aiocblist) aio_freejobs;		/* Pool of free jobs */
218 
219 static void	aio_init_aioinfo(struct proc *p);
220 static void	aio_onceonly(void *);
221 static int	aio_free_entry(struct aiocblist *aiocbe);
222 static void	aio_process(struct aiocblist *aiocbe);
223 static int	aio_newproc(void);
224 static int	aio_aqueue(struct aiocb *job, int type);
225 static void	aio_physwakeup(struct bio *bio);
226 static int	aio_fphysio(struct aiocblist *aiocbe);
227 static int	aio_qphysio(struct proc *p, struct aiocblist *iocb);
228 static void	aio_daemon(void *uproc);
229 static void	process_signal(void *aioj);
230 
231 SYSINIT(aio, SI_SUB_VFS, SI_ORDER_ANY, aio_onceonly, NULL);
232 
233 /*
234  * Zones for:
235  * 	kaio	Per process async io info
236  *	aiop	async io thread data
237  *	aiocb	async io jobs
238  *	aiol	list io job pointer - internal to aio_suspend XXX
239  *	aiolio	list io jobs
240  */
241 static vm_zone_t kaio_zone, aiop_zone, aiocb_zone, aiol_zone, aiolio_zone;
242 
243 /*
244  * Startup initialization
245  */
246 static void
247 aio_onceonly(void *na)
248 {
249 	TAILQ_INIT(&aio_freeproc);
250 	TAILQ_INIT(&aio_activeproc);
251 	TAILQ_INIT(&aio_jobs);
252 	TAILQ_INIT(&aio_bufjobs);
253 	TAILQ_INIT(&aio_freejobs);
254 	kaio_zone = zinit("AIO", sizeof(struct kaioinfo), 0, 0, 1);
255 	aiop_zone = zinit("AIOP", sizeof(struct aioproclist), 0, 0, 1);
256 	aiocb_zone = zinit("AIOCB", sizeof(struct aiocblist), 0, 0, 1);
257 	aiol_zone = zinit("AIOL", AIO_LISTIO_MAX*sizeof(intptr_t), 0, 0, 1);
258 	aiolio_zone = zinit("AIOLIO", sizeof(struct aio_liojob), 0, 0, 1);
259 	aiod_timeout = AIOD_TIMEOUT_DEFAULT;
260 	aiod_lifetime = AIOD_LIFETIME_DEFAULT;
261 	jobrefid = 1;
262 }
263 
264 /*
265  * Init the per-process aioinfo structure.  The aioinfo limits are set
266  * per-process for user limit (resource) management.
267  */
268 static void
269 aio_init_aioinfo(struct proc *p)
270 {
271 	struct kaioinfo *ki;
272 	if (p->p_aioinfo == NULL) {
273 		ki = zalloc(kaio_zone);
274 		p->p_aioinfo = ki;
275 		ki->kaio_flags = 0;
276 		ki->kaio_maxactive_count = max_aio_per_proc;
277 		ki->kaio_active_count = 0;
278 		ki->kaio_qallowed_count = max_aio_queue_per_proc;
279 		ki->kaio_queue_count = 0;
280 		ki->kaio_ballowed_count = max_buf_aio;
281 		ki->kaio_buffer_count = 0;
282 		ki->kaio_buffer_finished_count = 0;
283 		ki->kaio_p = p;
284 		TAILQ_INIT(&ki->kaio_jobdone);
285 		TAILQ_INIT(&ki->kaio_jobqueue);
286 		TAILQ_INIT(&ki->kaio_bufdone);
287 		TAILQ_INIT(&ki->kaio_bufqueue);
288 		TAILQ_INIT(&ki->kaio_liojoblist);
289 		TAILQ_INIT(&ki->kaio_sockqueue);
290 	}
291 
292 	while (num_aio_procs < target_aio_procs)
293 		aio_newproc();
294 }
295 
296 /*
297  * Free a job entry.  Wait for completion if it is currently active, but don't
298  * delay forever.  If we delay, we return a flag that says that we have to
299  * restart the queue scan.
300  */
301 static int
302 aio_free_entry(struct aiocblist *aiocbe)
303 {
304 	struct kaioinfo *ki;
305 	struct aio_liojob *lj;
306 	struct proc *p;
307 	int error;
308 
309 	if (aiocbe->jobstate == JOBST_NULL)
310 		panic("aio_free_entry: freeing already free job");
311 
312 	p = aiocbe->userproc;
313 	ki = p->p_aioinfo;
314 	lj = aiocbe->lio;
315 	if (ki == NULL)
316 		panic("aio_free_entry: missing p->p_aioinfo");
317 
318 	while (aiocbe->jobstate == JOBST_JOBRUNNING) {
319 		aiocbe->jobflags |= AIOCBLIST_RUNDOWN;
320 		tsleep(aiocbe, 0, "jobwai", 0);
321 	}
322 	if (aiocbe->bp == NULL) {
323 		if (ki->kaio_queue_count <= 0)
324 			panic("aio_free_entry: process queue size <= 0");
325 		if (num_queue_count <= 0)
326 			panic("aio_free_entry: system wide queue size <= 0");
327 
328 		if (lj) {
329 			lj->lioj_queue_count--;
330 			if (aiocbe->jobflags & AIOCBLIST_DONE)
331 				lj->lioj_queue_finished_count--;
332 		}
333 		ki->kaio_queue_count--;
334 		if (aiocbe->jobflags & AIOCBLIST_DONE)
335 			ki->kaio_queue_finished_count--;
336 		num_queue_count--;
337 	} else {
338 		if (lj) {
339 			lj->lioj_buffer_count--;
340 			if (aiocbe->jobflags & AIOCBLIST_DONE)
341 				lj->lioj_buffer_finished_count--;
342 		}
343 		if (aiocbe->jobflags & AIOCBLIST_DONE)
344 			ki->kaio_buffer_finished_count--;
345 		ki->kaio_buffer_count--;
346 		num_buf_aio--;
347 	}
348 
349 	/* aiocbe is going away, we need to destroy any knotes */
350 	knote_remove(p->p_thread, &aiocbe->klist);
351 
352 	if ((ki->kaio_flags & KAIO_WAKEUP) || ((ki->kaio_flags & KAIO_RUNDOWN)
353 	    && ((ki->kaio_buffer_count == 0) && (ki->kaio_queue_count == 0)))) {
354 		ki->kaio_flags &= ~KAIO_WAKEUP;
355 		wakeup(p);
356 	}
357 
358 	if (aiocbe->jobstate == JOBST_JOBQBUF) {
359 		if ((error = aio_fphysio(aiocbe)) != 0)
360 			return error;
361 		if (aiocbe->jobstate != JOBST_JOBBFINISHED)
362 			panic("aio_free_entry: invalid physio finish-up state");
363 		crit_enter();
364 		TAILQ_REMOVE(&ki->kaio_bufdone, aiocbe, plist);
365 		crit_exit();
366 	} else if (aiocbe->jobstate == JOBST_JOBQGLOBAL) {
367 		crit_enter();
368 		TAILQ_REMOVE(&aio_jobs, aiocbe, list);
369 		TAILQ_REMOVE(&ki->kaio_jobqueue, aiocbe, plist);
370 		crit_exit();
371 	} else if (aiocbe->jobstate == JOBST_JOBFINISHED)
372 		TAILQ_REMOVE(&ki->kaio_jobdone, aiocbe, plist);
373 	else if (aiocbe->jobstate == JOBST_JOBBFINISHED) {
374 		crit_enter();
375 		TAILQ_REMOVE(&ki->kaio_bufdone, aiocbe, plist);
376 		crit_exit();
377 		if (aiocbe->bp) {
378 			vunmapbuf(aiocbe->bp);
379 			relpbuf(aiocbe->bp, NULL);
380 			aiocbe->bp = NULL;
381 		}
382 	}
383 	if (lj && (lj->lioj_buffer_count == 0) && (lj->lioj_queue_count == 0)) {
384 		TAILQ_REMOVE(&ki->kaio_liojoblist, lj, lioj_list);
385 		zfree(aiolio_zone, lj);
386 	}
387 	aiocbe->jobstate = JOBST_NULL;
388 	callout_stop(&aiocbe->timeout);
389 	fdrop(aiocbe->fd_file);
390 	TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
391 	return 0;
392 }
393 #endif /* VFS_AIO */
394 
395 /*
396  * Rundown the jobs for a given process.
397  */
398 void
399 aio_proc_rundown(struct proc *p)
400 {
401 #ifndef VFS_AIO
402 	return;
403 #else
404 	struct kaioinfo *ki;
405 	struct aio_liojob *lj, *ljn;
406 	struct aiocblist *aiocbe, *aiocbn;
407 	struct file *fp;
408 	struct socket *so;
409 
410 	ki = p->p_aioinfo;
411 	if (ki == NULL)
412 		return;
413 
414 	ki->kaio_flags |= LIOJ_SIGNAL_POSTED;
415 	while ((ki->kaio_active_count > 0) || (ki->kaio_buffer_count >
416 	    ki->kaio_buffer_finished_count)) {
417 		ki->kaio_flags |= KAIO_RUNDOWN;
418 		if (tsleep(p, 0, "kaiowt", aiod_timeout))
419 			break;
420 	}
421 
422 	/*
423 	 * Move any aio ops that are waiting on socket I/O to the normal job
424 	 * queues so they are cleaned up with any others.
425 	 */
426 	crit_enter();
427 	for (aiocbe = TAILQ_FIRST(&ki->kaio_sockqueue); aiocbe; aiocbe =
428 	    aiocbn) {
429 		aiocbn = TAILQ_NEXT(aiocbe, plist);
430 		fp = aiocbe->fd_file;
431 		if (fp != NULL) {
432 			so = (struct socket *)fp->f_data;
433 			TAILQ_REMOVE(&so->so_aiojobq, aiocbe, list);
434 			if (TAILQ_EMPTY(&so->so_aiojobq)) {
435 				so->so_snd.sb_flags &= ~SB_AIO;
436 				so->so_rcv.sb_flags &= ~SB_AIO;
437 			}
438 		}
439 		TAILQ_REMOVE(&ki->kaio_sockqueue, aiocbe, plist);
440 		TAILQ_INSERT_HEAD(&aio_jobs, aiocbe, list);
441 		TAILQ_INSERT_HEAD(&ki->kaio_jobqueue, aiocbe, plist);
442 	}
443 	crit_exit();
444 
445 restart1:
446 	for (aiocbe = TAILQ_FIRST(&ki->kaio_jobdone); aiocbe; aiocbe = aiocbn) {
447 		aiocbn = TAILQ_NEXT(aiocbe, plist);
448 		if (aio_free_entry(aiocbe))
449 			goto restart1;
450 	}
451 
452 restart2:
453 	for (aiocbe = TAILQ_FIRST(&ki->kaio_jobqueue); aiocbe; aiocbe =
454 	    aiocbn) {
455 		aiocbn = TAILQ_NEXT(aiocbe, plist);
456 		if (aio_free_entry(aiocbe))
457 			goto restart2;
458 	}
459 
460 restart3:
461 	crit_enter();
462 	while (TAILQ_FIRST(&ki->kaio_bufqueue)) {
463 		ki->kaio_flags |= KAIO_WAKEUP;
464 		tsleep(p, 0, "aioprn", 0);
465 		crit_exit();
466 		goto restart3;
467 	}
468 	crit_exit();
469 
470 restart4:
471 	crit_enter();
472 	for (aiocbe = TAILQ_FIRST(&ki->kaio_bufdone); aiocbe; aiocbe = aiocbn) {
473 		aiocbn = TAILQ_NEXT(aiocbe, plist);
474 		if (aio_free_entry(aiocbe)) {
475 			crit_exit();
476 			goto restart4;
477 		}
478 	}
479 	crit_exit();
480 
481         /*
482          * If we've slept, jobs might have moved from one queue to another.
483          * Retry rundown if we didn't manage to empty the queues.
484          */
485         if (TAILQ_FIRST(&ki->kaio_jobdone) != NULL ||
486 	    TAILQ_FIRST(&ki->kaio_jobqueue) != NULL ||
487 	    TAILQ_FIRST(&ki->kaio_bufqueue) != NULL ||
488 	    TAILQ_FIRST(&ki->kaio_bufdone) != NULL)
489 		goto restart1;
490 
491 	for (lj = TAILQ_FIRST(&ki->kaio_liojoblist); lj; lj = ljn) {
492 		ljn = TAILQ_NEXT(lj, lioj_list);
493 		if ((lj->lioj_buffer_count == 0) && (lj->lioj_queue_count ==
494 		    0)) {
495 			TAILQ_REMOVE(&ki->kaio_liojoblist, lj, lioj_list);
496 			zfree(aiolio_zone, lj);
497 		} else {
498 #ifdef DIAGNOSTIC
499 			printf("LIO job not cleaned up: B:%d, BF:%d, Q:%d, "
500 			    "QF:%d\n", lj->lioj_buffer_count,
501 			    lj->lioj_buffer_finished_count,
502 			    lj->lioj_queue_count,
503 			    lj->lioj_queue_finished_count);
504 #endif
505 		}
506 	}
507 
508 	zfree(kaio_zone, ki);
509 	p->p_aioinfo = NULL;
510 #endif /* VFS_AIO */
511 }
512 
513 #ifdef VFS_AIO
514 /*
515  * Select a job to run (called by an AIO daemon).
516  */
517 static struct aiocblist *
518 aio_selectjob(struct aioproclist *aiop)
519 {
520 	struct aiocblist *aiocbe;
521 	struct kaioinfo *ki;
522 	struct proc *userp;
523 
524 	crit_enter();
525 	for (aiocbe = TAILQ_FIRST(&aio_jobs); aiocbe; aiocbe =
526 	    TAILQ_NEXT(aiocbe, list)) {
527 		userp = aiocbe->userproc;
528 		ki = userp->p_aioinfo;
529 
530 		if (ki->kaio_active_count < ki->kaio_maxactive_count) {
531 			TAILQ_REMOVE(&aio_jobs, aiocbe, list);
532 			crit_exit();
533 			return aiocbe;
534 		}
535 	}
536 	crit_exit();
537 
538 	return NULL;
539 }
540 
541 /*
542  * The AIO processing activity.  This is the code that does the I/O request for
543  * the non-physio version of the operations.  The normal vn operations are used,
544  * and this code should work in all instances for every type of file, including
545  * pipes, sockets, fifos, and regular files.
546  */
547 static void
548 aio_process(struct aiocblist *aiocbe)
549 {
550 	struct thread *mytd;
551 	struct aiocb *cb;
552 	struct file *fp;
553 	struct uio auio;
554 	struct iovec aiov;
555 	int cnt;
556 	int error;
557 	int oublock_st, oublock_end;
558 	int inblock_st, inblock_end;
559 
560 	mytd = curthread;
561 	cb = &aiocbe->uaiocb;
562 	fp = aiocbe->fd_file;
563 
564 	aiov.iov_base = (void *)(uintptr_t)cb->aio_buf;
565 	aiov.iov_len = cb->aio_nbytes;
566 
567 	auio.uio_iov = &aiov;
568 	auio.uio_iovcnt = 1;
569 	auio.uio_offset = cb->aio_offset;
570 	auio.uio_resid = cb->aio_nbytes;
571 	cnt = cb->aio_nbytes;
572 	auio.uio_segflg = UIO_USERSPACE;
573 	auio.uio_td = mytd;
574 
575 	inblock_st = mytd->td_proc->p_stats->p_ru.ru_inblock;
576 	oublock_st = mytd->td_proc->p_stats->p_ru.ru_oublock;
577 	/*
578 	 * _aio_aqueue() acquires a reference to the file that is
579 	 * released in aio_free_entry().
580 	 */
581 	if (cb->aio_lio_opcode == LIO_READ) {
582 		auio.uio_rw = UIO_READ;
583 		error = fo_read(fp, &auio, fp->f_cred, O_FOFFSET);
584 	} else {
585 		auio.uio_rw = UIO_WRITE;
586 		error = fo_write(fp, &auio, fp->f_cred, O_FOFFSET);
587 	}
588 	inblock_end = mytd->td_proc->p_stats->p_ru.ru_inblock;
589 	oublock_end = mytd->td_proc->p_stats->p_ru.ru_oublock;
590 
591 	aiocbe->inputcharge = inblock_end - inblock_st;
592 	aiocbe->outputcharge = oublock_end - oublock_st;
593 
594 	if ((error) && (auio.uio_resid != cnt)) {
595 		if (error == ERESTART || error == EINTR || error == EWOULDBLOCK)
596 			error = 0;
597 		if ((error == EPIPE) && (cb->aio_lio_opcode == LIO_WRITE))
598 			psignal(aiocbe->userproc, SIGPIPE);
599 	}
600 
601 	cnt -= auio.uio_resid;
602 	cb->_aiocb_private.error = error;
603 	cb->_aiocb_private.status = cnt;
604 }
605 
606 /*
607  * The AIO daemon, most of the actual work is done in aio_process,
608  * but the setup (and address space mgmt) is done in this routine.
609  *
610  * The MP lock is held on entry.
611  */
612 static void
613 aio_daemon(void *uproc)
614 {
615 	struct aio_liojob *lj;
616 	struct aiocb *cb;
617 	struct aiocblist *aiocbe;
618 	struct aioproclist *aiop;
619 	struct kaioinfo *ki;
620 	struct proc *curcp, *mycp, *userp;
621 	struct vmspace *myvm, *tmpvm;
622 	struct ucred *cr;
623 
624 	/*
625 	 * Local copies of curproc (cp) and vmspace (myvm)
626 	 */
627 	mycp = curproc;
628 	myvm = mycp->p_vmspace;
629 
630 	if (mycp->p_textvp) {
631 		vrele(mycp->p_textvp);
632 		mycp->p_textvp = NULL;
633 	}
634 
635 	/*
636 	 * Allocate and ready the aio control info.  There is one aiop structure
637 	 * per daemon.
638 	 */
639 	aiop = zalloc(aiop_zone);
640 	aiop->aioproc = mycp;
641 	aiop->aioprocflags |= AIOP_FREE;
642 
643 	crit_enter();
644 
645 	/*
646 	 * Place thread (lightweight process) onto the AIO free thread list.
647 	 */
648 	if (TAILQ_EMPTY(&aio_freeproc))
649 		wakeup(&aio_freeproc);
650 	TAILQ_INSERT_HEAD(&aio_freeproc, aiop, list);
651 
652 	crit_exit();
653 
654 	/* Make up a name for the daemon. */
655 	strcpy(mycp->p_comm, "aiod");
656 
657 	/*
658 	 * Get rid of our current filedescriptors.  AIOD's don't need any
659 	 * filedescriptors, except as temporarily inherited from the client.
660 	 * Credentials are also cloned, and made equivalent to "root".
661 	 */
662 	fdfree(mycp);
663 	mycp->p_fd = NULL;
664 	cr = cratom(&mycp->p_ucred);
665 	cr->cr_uid = 0;
666 	uireplace(&cr->cr_uidinfo, uifind(0));
667 	cr->cr_ngroups = 1;
668 	cr->cr_groups[0] = 1;
669 
670 	/* The daemon resides in its own pgrp. */
671 	enterpgrp(mycp, mycp->p_pid, 1);
672 
673 	/* Mark special process type. */
674 	mycp->p_flag |= P_SYSTEM | P_KTHREADP;
675 
676 	/*
677 	 * Wakeup parent process.  (Parent sleeps to keep from blasting away
678 	 * and creating too many daemons.)
679 	 */
680 	wakeup(mycp);
681 
682 	for (;;) {
683 		/*
684 		 * curcp is the current daemon process context.
685 		 * userp is the current user process context.
686 		 */
687 		curcp = mycp;
688 
689 		/*
690 		 * Take daemon off of free queue
691 		 */
692 		if (aiop->aioprocflags & AIOP_FREE) {
693 			crit_enter();
694 			TAILQ_REMOVE(&aio_freeproc, aiop, list);
695 			TAILQ_INSERT_TAIL(&aio_activeproc, aiop, list);
696 			aiop->aioprocflags &= ~AIOP_FREE;
697 			crit_exit();
698 		}
699 		aiop->aioprocflags &= ~AIOP_SCHED;
700 
701 		/*
702 		 * Check for jobs.
703 		 */
704 		while ((aiocbe = aio_selectjob(aiop)) != NULL) {
705 			cb = &aiocbe->uaiocb;
706 			userp = aiocbe->userproc;
707 
708 			aiocbe->jobstate = JOBST_JOBRUNNING;
709 
710 			/*
711 			 * Connect to process address space for user program.
712 			 */
713 			if (userp != curcp) {
714 				/*
715 				 * Save the current address space that we are
716 				 * connected to.
717 				 */
718 				tmpvm = mycp->p_vmspace;
719 
720 				/*
721 				 * Point to the new user address space, and
722 				 * refer to it.
723 				 */
724 				mycp->p_vmspace = userp->p_vmspace;
725 				mycp->p_vmspace->vm_refcnt++;
726 
727 				/* Activate the new mapping. */
728 				pmap_activate(mycp);
729 
730 				/*
731 				 * If the old address space wasn't the daemons
732 				 * own address space, then we need to remove the
733 				 * daemon's reference from the other process
734 				 * that it was acting on behalf of.
735 				 */
736 				if (tmpvm != myvm) {
737 					vmspace_free(tmpvm);
738 				}
739 				curcp = userp;
740 			}
741 
742 			ki = userp->p_aioinfo;
743 			lj = aiocbe->lio;
744 
745 			/* Account for currently active jobs. */
746 			ki->kaio_active_count++;
747 
748 			/* Do the I/O function. */
749 			aio_process(aiocbe);
750 
751 			/* Decrement the active job count. */
752 			ki->kaio_active_count--;
753 
754 			/*
755 			 * Increment the completion count for wakeup/signal
756 			 * comparisons.
757 			 */
758 			aiocbe->jobflags |= AIOCBLIST_DONE;
759 			ki->kaio_queue_finished_count++;
760 			if (lj)
761 				lj->lioj_queue_finished_count++;
762 			if ((ki->kaio_flags & KAIO_WAKEUP) || ((ki->kaio_flags
763 			    & KAIO_RUNDOWN) && (ki->kaio_active_count == 0))) {
764 				ki->kaio_flags &= ~KAIO_WAKEUP;
765 				wakeup(userp);
766 			}
767 
768 			crit_enter();
769 			if (lj && (lj->lioj_flags &
770 			    (LIOJ_SIGNAL|LIOJ_SIGNAL_POSTED)) == LIOJ_SIGNAL) {
771 				if ((lj->lioj_queue_finished_count ==
772 				    lj->lioj_queue_count) &&
773 				    (lj->lioj_buffer_finished_count ==
774 				    lj->lioj_buffer_count)) {
775 						psignal(userp,
776 						    lj->lioj_signal.sigev_signo);
777 						lj->lioj_flags |=
778 						    LIOJ_SIGNAL_POSTED;
779 				}
780 			}
781 			crit_exit();
782 
783 			aiocbe->jobstate = JOBST_JOBFINISHED;
784 
785 			crit_enter();
786 			TAILQ_REMOVE(&ki->kaio_jobqueue, aiocbe, plist);
787 			TAILQ_INSERT_TAIL(&ki->kaio_jobdone, aiocbe, plist);
788 			crit_exit();
789 			KNOTE(&aiocbe->klist, 0);
790 
791 			if (aiocbe->jobflags & AIOCBLIST_RUNDOWN) {
792 				wakeup(aiocbe);
793 				aiocbe->jobflags &= ~AIOCBLIST_RUNDOWN;
794 			}
795 
796 			if (cb->aio_sigevent.sigev_notify == SIGEV_SIGNAL) {
797 				psignal(userp, cb->aio_sigevent.sigev_signo);
798 			}
799 		}
800 
801 		/*
802 		 * Disconnect from user address space.
803 		 */
804 		if (curcp != mycp) {
805 			/* Get the user address space to disconnect from. */
806 			tmpvm = mycp->p_vmspace;
807 
808 			/* Get original address space for daemon. */
809 			mycp->p_vmspace = myvm;
810 
811 			/* Activate the daemon's address space. */
812 			pmap_activate(mycp);
813 #ifdef DIAGNOSTIC
814 			if (tmpvm == myvm) {
815 				printf("AIOD: vmspace problem -- %d\n",
816 				    mycp->p_pid);
817 			}
818 #endif
819 			/* Remove our vmspace reference. */
820 			vmspace_free(tmpvm);
821 
822 			curcp = mycp;
823 		}
824 
825 		/*
826 		 * If we are the first to be put onto the free queue, wakeup
827 		 * anyone waiting for a daemon.
828 		 */
829 		crit_enter();
830 		TAILQ_REMOVE(&aio_activeproc, aiop, list);
831 		if (TAILQ_EMPTY(&aio_freeproc))
832 			wakeup(&aio_freeproc);
833 		TAILQ_INSERT_HEAD(&aio_freeproc, aiop, list);
834 		aiop->aioprocflags |= AIOP_FREE;
835 		crit_exit();
836 
837 		/*
838 		 * If daemon is inactive for a long time, allow it to exit,
839 		 * thereby freeing resources.
840 		 */
841 		if (((aiop->aioprocflags & AIOP_SCHED) == 0) && tsleep(mycp,
842 		    0, "aiordy", aiod_lifetime)) {
843 			crit_enter();
844 			if (TAILQ_EMPTY(&aio_jobs)) {
845 				if ((aiop->aioprocflags & AIOP_FREE) &&
846 				    (num_aio_procs > target_aio_procs)) {
847 					TAILQ_REMOVE(&aio_freeproc, aiop, list);
848 					crit_exit();
849 					zfree(aiop_zone, aiop);
850 					num_aio_procs--;
851 #ifdef DIAGNOSTIC
852 					if (mycp->p_vmspace->vm_refcnt <= 1) {
853 						printf("AIOD: bad vm refcnt for"
854 						    " exiting daemon: %d\n",
855 						    mycp->p_vmspace->vm_refcnt);
856 					}
857 #endif
858 					exit1(0);
859 				}
860 			}
861 			crit_exit();
862 		}
863 	}
864 }
865 
866 /*
867  * Create a new AIO daemon.  This is mostly a kernel-thread fork routine.  The
868  * AIO daemon modifies its environment itself.
869  */
870 static int
871 aio_newproc()
872 {
873 	int error;
874 	struct lwp *lp;
875 	struct proc *np;
876 
877 	lp = &proc0.p_lwp;
878 	error = fork1(lp, RFPROC|RFMEM|RFNOWAIT, &np);
879 	if (error)
880 		return error;
881 	cpu_set_fork_handler(np, aio_daemon, curproc);
882 	start_forked_proc(lp, np);
883 
884 	/*
885 	 * Wait until daemon is started, but continue on just in case to
886 	 * handle error conditions.
887 	 */
888 	error = tsleep(np, 0, "aiosta", aiod_timeout);
889 	num_aio_procs++;
890 
891 	return error;
892 }
893 
894 /*
895  * Try the high-performance, low-overhead physio method for eligible
896  * VCHR devices.  This method doesn't use an aio helper thread, and
897  * thus has very low overhead.
898  *
899  * Assumes that the caller, _aio_aqueue(), has incremented the file
900  * structure's reference count, preventing its deallocation for the
901  * duration of this call.
902  */
903 static int
904 aio_qphysio(struct proc *p, struct aiocblist *aiocbe)
905 {
906 	int error;
907 	struct aiocb *cb;
908 	struct file *fp;
909 	struct buf *bp;
910 	struct vnode *vp;
911 	struct kaioinfo *ki;
912 	struct aio_liojob *lj;
913 	int notify;
914 
915 	cb = &aiocbe->uaiocb;
916 	fp = aiocbe->fd_file;
917 
918 	if (fp->f_type != DTYPE_VNODE)
919 		return (-1);
920 
921 	vp = (struct vnode *)fp->f_data;
922 
923 	/*
924 	 * If its not a disk, we don't want to return a positive error.
925 	 * It causes the aio code to not fall through to try the thread
926 	 * way when you're talking to a regular file.
927 	 */
928 	if (!vn_isdisk(vp, &error)) {
929 		if (error == ENOTBLK)
930 			return (-1);
931 		else
932 			return (error);
933 	}
934 
935  	if (cb->aio_nbytes % vp->v_rdev->si_bsize_phys)
936 		return (-1);
937 
938 	if (cb->aio_nbytes >
939 	    MAXPHYS - (((vm_offset_t) cb->aio_buf) & PAGE_MASK))
940 		return (-1);
941 
942 	ki = p->p_aioinfo;
943 	if (ki->kaio_buffer_count >= ki->kaio_ballowed_count)
944 		return (-1);
945 
946 	ki->kaio_buffer_count++;
947 
948 	lj = aiocbe->lio;
949 	if (lj)
950 		lj->lioj_buffer_count++;
951 
952 	/* Create and build a buffer header for a transfer. */
953 	bp = getpbuf(NULL);
954 	BUF_KERNPROC(bp);
955 
956 	/*
957 	 * Get a copy of the kva from the physical buffer.
958 	 */
959 	bp->b_bio1.bio_caller_info1.ptr = p;
960 	error = 0;
961 
962 	bp->b_cmd = (cb->aio_lio_opcode == LIO_WRITE) ?
963 		    BUF_CMD_WRITE : BUF_CMD_READ;
964 	bp->b_bio1.bio_done = aio_physwakeup;
965 	bp->b_bio1.bio_offset = cb->aio_offset;
966 
967 	/* Bring buffer into kernel space. */
968 	if (vmapbuf(bp, __DEVOLATILE(char *, cb->aio_buf), cb->aio_nbytes) < 0) {
969 		error = EFAULT;
970 		goto doerror;
971 	}
972 
973 	crit_enter();
974 
975 	aiocbe->bp = bp;
976 	bp->b_bio1.bio_caller_info2.ptr = aiocbe;
977 	TAILQ_INSERT_TAIL(&aio_bufjobs, aiocbe, list);
978 	TAILQ_INSERT_TAIL(&ki->kaio_bufqueue, aiocbe, plist);
979 	aiocbe->jobstate = JOBST_JOBQBUF;
980 	cb->_aiocb_private.status = cb->aio_nbytes;
981 	num_buf_aio++;
982 	bp->b_error = 0;
983 
984 	crit_exit();
985 
986 	/* Perform transfer. */
987 	dev_dstrategy(vp->v_rdev, &bp->b_bio1);
988 
989 	notify = 0;
990 	crit_enter();
991 
992 	/*
993 	 * If we had an error invoking the request, or an error in processing
994 	 * the request before we have returned, we process it as an error in
995 	 * transfer.  Note that such an I/O error is not indicated immediately,
996 	 * but is returned using the aio_error mechanism.  In this case,
997 	 * aio_suspend will return immediately.
998 	 */
999 	if (bp->b_error || (bp->b_flags & B_ERROR)) {
1000 		struct aiocb *job = aiocbe->uuaiocb;
1001 
1002 		aiocbe->uaiocb._aiocb_private.status = 0;
1003 		suword(&job->_aiocb_private.status, 0);
1004 		aiocbe->uaiocb._aiocb_private.error = bp->b_error;
1005 		suword(&job->_aiocb_private.error, bp->b_error);
1006 
1007 		ki->kaio_buffer_finished_count++;
1008 
1009 		if (aiocbe->jobstate != JOBST_JOBBFINISHED) {
1010 			aiocbe->jobstate = JOBST_JOBBFINISHED;
1011 			aiocbe->jobflags |= AIOCBLIST_DONE;
1012 			TAILQ_REMOVE(&aio_bufjobs, aiocbe, list);
1013 			TAILQ_REMOVE(&ki->kaio_bufqueue, aiocbe, plist);
1014 			TAILQ_INSERT_TAIL(&ki->kaio_bufdone, aiocbe, plist);
1015 			notify = 1;
1016 		}
1017 	}
1018 	crit_exit();
1019 	if (notify)
1020 		KNOTE(&aiocbe->klist, 0);
1021 	return 0;
1022 
1023 doerror:
1024 	ki->kaio_buffer_count--;
1025 	if (lj)
1026 		lj->lioj_buffer_count--;
1027 	aiocbe->bp = NULL;
1028 	relpbuf(bp, NULL);
1029 	return error;
1030 }
1031 
1032 /*
1033  * This waits/tests physio completion.
1034  */
1035 static int
1036 aio_fphysio(struct aiocblist *iocb)
1037 {
1038 	struct buf *bp;
1039 	int error;
1040 
1041 	bp = iocb->bp;
1042 
1043 	crit_enter();
1044 	while (bp->b_cmd != BUF_CMD_DONE) {
1045 		if (tsleep(bp, 0, "physstr", aiod_timeout)) {
1046 			if (bp->b_cmd != BUF_CMD_DONE) {
1047 				crit_exit();
1048 				return EINPROGRESS;
1049 			} else {
1050 				break;
1051 			}
1052 		}
1053 	}
1054 	crit_exit();
1055 
1056 	/* Release mapping into kernel space. */
1057 	vunmapbuf(bp);
1058 	iocb->bp = 0;
1059 
1060 	error = 0;
1061 
1062 	/* Check for an error. */
1063 	if (bp->b_flags & B_ERROR)
1064 		error = bp->b_error;
1065 
1066 	relpbuf(bp, NULL);
1067 	return (error);
1068 }
1069 #endif /* VFS_AIO */
1070 
1071 /*
1072  * Wake up aio requests that may be serviceable now.
1073  */
1074 void
1075 aio_swake(struct socket *so, struct sockbuf *sb)
1076 {
1077 #ifndef VFS_AIO
1078 	return;
1079 #else
1080 	struct aiocblist *cb,*cbn;
1081 	struct proc *p;
1082 	struct kaioinfo *ki = NULL;
1083 	int opcode, wakecount = 0;
1084 	struct aioproclist *aiop;
1085 
1086 	if (sb == &so->so_snd) {
1087 		opcode = LIO_WRITE;
1088 		so->so_snd.sb_flags &= ~SB_AIO;
1089 	} else {
1090 		opcode = LIO_READ;
1091 		so->so_rcv.sb_flags &= ~SB_AIO;
1092 	}
1093 
1094 	for (cb = TAILQ_FIRST(&so->so_aiojobq); cb; cb = cbn) {
1095 		cbn = TAILQ_NEXT(cb, list);
1096 		if (opcode == cb->uaiocb.aio_lio_opcode) {
1097 			p = cb->userproc;
1098 			ki = p->p_aioinfo;
1099 			TAILQ_REMOVE(&so->so_aiojobq, cb, list);
1100 			TAILQ_REMOVE(&ki->kaio_sockqueue, cb, plist);
1101 			TAILQ_INSERT_TAIL(&aio_jobs, cb, list);
1102 			TAILQ_INSERT_TAIL(&ki->kaio_jobqueue, cb, plist);
1103 			wakecount++;
1104 			if (cb->jobstate != JOBST_JOBQGLOBAL)
1105 				panic("invalid queue value");
1106 		}
1107 	}
1108 
1109 	while (wakecount--) {
1110 		if ((aiop = TAILQ_FIRST(&aio_freeproc)) != 0) {
1111 			TAILQ_REMOVE(&aio_freeproc, aiop, list);
1112 			TAILQ_INSERT_TAIL(&aio_activeproc, aiop, list);
1113 			aiop->aioprocflags &= ~AIOP_FREE;
1114 			wakeup(aiop->aioproc);
1115 		}
1116 	}
1117 #endif /* VFS_AIO */
1118 }
1119 
1120 #ifdef VFS_AIO
1121 /*
1122  * Queue a new AIO request.  Choosing either the threaded or direct physio VCHR
1123  * technique is done in this code.
1124  */
1125 static int
1126 _aio_aqueue(struct aiocb *job, struct aio_liojob *lj, int type)
1127 {
1128 	struct proc *p = curproc;
1129 	struct filedesc *fdp;
1130 	struct file *fp;
1131 	unsigned int fd;
1132 	struct socket *so;
1133 	int error;
1134 	int opcode, user_opcode;
1135 	struct aiocblist *aiocbe;
1136 	struct aioproclist *aiop;
1137 	struct kaioinfo *ki;
1138 	struct kevent kev;
1139 	struct kqueue *kq;
1140 	struct file *kq_fp;
1141 
1142 	if ((aiocbe = TAILQ_FIRST(&aio_freejobs)) != NULL)
1143 		TAILQ_REMOVE(&aio_freejobs, aiocbe, list);
1144 	else
1145 		aiocbe = zalloc (aiocb_zone);
1146 
1147 	aiocbe->inputcharge = 0;
1148 	aiocbe->outputcharge = 0;
1149 	callout_init(&aiocbe->timeout);
1150 	SLIST_INIT(&aiocbe->klist);
1151 
1152 	suword(&job->_aiocb_private.status, -1);
1153 	suword(&job->_aiocb_private.error, 0);
1154 	suword(&job->_aiocb_private.kernelinfo, -1);
1155 
1156 	error = copyin(job, &aiocbe->uaiocb, sizeof(aiocbe->uaiocb));
1157 	if (error) {
1158 		suword(&job->_aiocb_private.error, error);
1159 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1160 		return error;
1161 	}
1162 	if (aiocbe->uaiocb.aio_sigevent.sigev_notify == SIGEV_SIGNAL &&
1163 	    !_SIG_VALID(aiocbe->uaiocb.aio_sigevent.sigev_signo)) {
1164 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1165 		return EINVAL;
1166 	}
1167 
1168 	/* Save userspace address of the job info. */
1169 	aiocbe->uuaiocb = job;
1170 
1171 	/* Get the opcode. */
1172 	user_opcode = aiocbe->uaiocb.aio_lio_opcode;
1173 	if (type != LIO_NOP)
1174 		aiocbe->uaiocb.aio_lio_opcode = type;
1175 	opcode = aiocbe->uaiocb.aio_lio_opcode;
1176 
1177 	/* Get the fd info for process. */
1178 	fdp = p->p_fd;
1179 
1180 	/*
1181 	 * Range check file descriptor.
1182 	 */
1183 	fd = aiocbe->uaiocb.aio_fildes;
1184 	if (fd >= fdp->fd_nfiles) {
1185 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1186 		if (type == 0)
1187 			suword(&job->_aiocb_private.error, EBADF);
1188 		return EBADF;
1189 	}
1190 
1191 	fp = aiocbe->fd_file = fdp->fd_files[fd].fp;
1192 	if ((fp == NULL) || ((opcode == LIO_WRITE) && ((fp->f_flag & FWRITE) ==
1193 	    0))) {
1194 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1195 		if (type == 0)
1196 			suword(&job->_aiocb_private.error, EBADF);
1197 		return EBADF;
1198 	}
1199 	fhold(fp);
1200 
1201 	if (aiocbe->uaiocb.aio_offset == -1LL) {
1202 		error = EINVAL;
1203 		goto aqueue_fail;
1204 	}
1205 	error = suword(&job->_aiocb_private.kernelinfo, jobrefid);
1206 	if (error) {
1207 		error = EINVAL;
1208 		goto aqueue_fail;
1209 	}
1210 	aiocbe->uaiocb._aiocb_private.kernelinfo = (void *)(intptr_t)jobrefid;
1211 	if (jobrefid == LONG_MAX)
1212 		jobrefid = 1;
1213 	else
1214 		jobrefid++;
1215 
1216 	if (opcode == LIO_NOP) {
1217 		fdrop(fp);
1218 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1219 		if (type == 0) {
1220 			suword(&job->_aiocb_private.error, 0);
1221 			suword(&job->_aiocb_private.status, 0);
1222 			suword(&job->_aiocb_private.kernelinfo, 0);
1223 		}
1224 		return 0;
1225 	}
1226 	if ((opcode != LIO_READ) && (opcode != LIO_WRITE)) {
1227 		if (type == 0)
1228 			suword(&job->_aiocb_private.status, 0);
1229 		error = EINVAL;
1230 		goto aqueue_fail;
1231 	}
1232 
1233 	if (aiocbe->uaiocb.aio_sigevent.sigev_notify == SIGEV_KEVENT) {
1234 		kev.ident = aiocbe->uaiocb.aio_sigevent.sigev_notify_kqueue;
1235 		kev.udata = aiocbe->uaiocb.aio_sigevent.sigev_value.sigval_ptr;
1236 	}
1237 	else {
1238 		/*
1239 		 * This method for requesting kevent-based notification won't
1240 		 * work on the alpha, since we're passing in a pointer
1241 		 * via aio_lio_opcode, which is an int.  Use the SIGEV_KEVENT-
1242 		 * based method instead.
1243 		 */
1244 		if (user_opcode == LIO_NOP || user_opcode == LIO_READ ||
1245 		    user_opcode == LIO_WRITE)
1246 			goto no_kqueue;
1247 
1248 		error = copyin((struct kevent *)(uintptr_t)user_opcode,
1249 		    &kev, sizeof(kev));
1250 		if (error)
1251 			goto aqueue_fail;
1252 	}
1253 	if ((u_int)kev.ident >= fdp->fd_nfiles ||
1254 	    (kq_fp = fdp->fd_files[kev.ident].fp) == NULL ||
1255 	    (kq_fp->f_type != DTYPE_KQUEUE)) {
1256 		error = EBADF;
1257 		goto aqueue_fail;
1258 	}
1259 	kq = (struct kqueue *)kq_fp->f_data;
1260 	kev.ident = (uintptr_t)aiocbe->uuaiocb;
1261 	kev.filter = EVFILT_AIO;
1262 	kev.flags = EV_ADD | EV_ENABLE | EV_FLAG1;
1263 	kev.data = (intptr_t)aiocbe;
1264 	error = kqueue_register(kq, &kev, p->p_thread);
1265 aqueue_fail:
1266 	if (error) {
1267 		fdrop(fp);
1268 		TAILQ_INSERT_HEAD(&aio_freejobs, aiocbe, list);
1269 		if (type == 0)
1270 			suword(&job->_aiocb_private.error, error);
1271 		goto done;
1272 	}
1273 no_kqueue:
1274 
1275 	suword(&job->_aiocb_private.error, EINPROGRESS);
1276 	aiocbe->uaiocb._aiocb_private.error = EINPROGRESS;
1277 	aiocbe->userproc = p;
1278 	aiocbe->jobflags = 0;
1279 	aiocbe->lio = lj;
1280 	ki = p->p_aioinfo;
1281 
1282 	if (fp->f_type == DTYPE_SOCKET) {
1283 		/*
1284 		 * Alternate queueing for socket ops: Reach down into the
1285 		 * descriptor to get the socket data.  Then check to see if the
1286 		 * socket is ready to be read or written (based on the requested
1287 		 * operation).
1288 		 *
1289 		 * If it is not ready for io, then queue the aiocbe on the
1290 		 * socket, and set the flags so we get a call when sbnotify()
1291 		 * happens.
1292 		 */
1293 		so = (struct socket *)fp->f_data;
1294 		crit_enter();
1295 		if (((opcode == LIO_READ) && (!soreadable(so))) || ((opcode ==
1296 		    LIO_WRITE) && (!sowriteable(so)))) {
1297 			TAILQ_INSERT_TAIL(&so->so_aiojobq, aiocbe, list);
1298 			TAILQ_INSERT_TAIL(&ki->kaio_sockqueue, aiocbe, plist);
1299 			if (opcode == LIO_READ)
1300 				so->so_rcv.sb_flags |= SB_AIO;
1301 			else
1302 				so->so_snd.sb_flags |= SB_AIO;
1303 			aiocbe->jobstate = JOBST_JOBQGLOBAL; /* XXX */
1304 			ki->kaio_queue_count++;
1305 			num_queue_count++;
1306 			crit_exit();
1307 			error = 0;
1308 			goto done;
1309 		}
1310 		crit_exit();
1311 	}
1312 
1313 	if ((error = aio_qphysio(p, aiocbe)) == 0)
1314 		goto done;
1315 	if (error > 0) {
1316 		suword(&job->_aiocb_private.status, 0);
1317 		aiocbe->uaiocb._aiocb_private.error = error;
1318 		suword(&job->_aiocb_private.error, error);
1319 		goto done;
1320 	}
1321 
1322 	/* No buffer for daemon I/O. */
1323 	aiocbe->bp = NULL;
1324 
1325 	ki->kaio_queue_count++;
1326 	if (lj)
1327 		lj->lioj_queue_count++;
1328 	crit_enter();
1329 	TAILQ_INSERT_TAIL(&ki->kaio_jobqueue, aiocbe, plist);
1330 	TAILQ_INSERT_TAIL(&aio_jobs, aiocbe, list);
1331 	crit_exit();
1332 	aiocbe->jobstate = JOBST_JOBQGLOBAL;
1333 
1334 	num_queue_count++;
1335 	error = 0;
1336 
1337 	/*
1338 	 * If we don't have a free AIO process, and we are below our quota, then
1339 	 * start one.  Otherwise, depend on the subsequent I/O completions to
1340 	 * pick-up this job.  If we don't successfully create the new process
1341 	 * (thread) due to resource issues, we return an error for now (EAGAIN),
1342 	 * which is likely not the correct thing to do.
1343 	 */
1344 	crit_enter();
1345 retryproc:
1346 	if ((aiop = TAILQ_FIRST(&aio_freeproc)) != NULL) {
1347 		TAILQ_REMOVE(&aio_freeproc, aiop, list);
1348 		TAILQ_INSERT_TAIL(&aio_activeproc, aiop, list);
1349 		aiop->aioprocflags &= ~AIOP_FREE;
1350 		wakeup(aiop->aioproc);
1351 	} else if (((num_aio_resv_start + num_aio_procs) < max_aio_procs) &&
1352 	    ((ki->kaio_active_count + num_aio_resv_start) <
1353 	    ki->kaio_maxactive_count)) {
1354 		num_aio_resv_start++;
1355 		if ((error = aio_newproc()) == 0) {
1356 			num_aio_resv_start--;
1357 			goto retryproc;
1358 		}
1359 		num_aio_resv_start--;
1360 	}
1361 	crit_exit();
1362 done:
1363 	return error;
1364 }
1365 
1366 /*
1367  * This routine queues an AIO request, checking for quotas.
1368  */
1369 static int
1370 aio_aqueue(struct aiocb *job, int type)
1371 {
1372 	struct proc *p = curproc;
1373 	struct kaioinfo *ki;
1374 
1375 	if (p->p_aioinfo == NULL)
1376 		aio_init_aioinfo(p);
1377 
1378 	if (num_queue_count >= max_queue_count)
1379 		return EAGAIN;
1380 
1381 	ki = p->p_aioinfo;
1382 	if (ki->kaio_queue_count >= ki->kaio_qallowed_count)
1383 		return EAGAIN;
1384 
1385 	return _aio_aqueue(job, NULL, type);
1386 }
1387 #endif /* VFS_AIO */
1388 
1389 /*
1390  * Support the aio_return system call, as a side-effect, kernel resources are
1391  * released.
1392  */
1393 int
1394 sys_aio_return(struct aio_return_args *uap)
1395 {
1396 #ifndef VFS_AIO
1397 	return ENOSYS;
1398 #else
1399 	struct proc *p = curproc;
1400 	long jobref;
1401 	struct aiocblist *cb, *ncb;
1402 	struct aiocb *ujob;
1403 	struct kaioinfo *ki;
1404 
1405 	ki = p->p_aioinfo;
1406 	if (ki == NULL)
1407 		return EINVAL;
1408 
1409 	ujob = uap->aiocbp;
1410 
1411 	jobref = fuword(&ujob->_aiocb_private.kernelinfo);
1412 	if (jobref == -1 || jobref == 0)
1413 		return EINVAL;
1414 
1415 	TAILQ_FOREACH(cb, &ki->kaio_jobdone, plist) {
1416 		if (((intptr_t) cb->uaiocb._aiocb_private.kernelinfo) ==
1417 		    jobref) {
1418 			if (ujob == cb->uuaiocb) {
1419 				uap->sysmsg_result =
1420 				    cb->uaiocb._aiocb_private.status;
1421 			} else
1422 				uap->sysmsg_result = EFAULT;
1423 			if (cb->uaiocb.aio_lio_opcode == LIO_WRITE) {
1424 				p->p_stats->p_ru.ru_oublock +=
1425 				    cb->outputcharge;
1426 				cb->outputcharge = 0;
1427 			} else if (cb->uaiocb.aio_lio_opcode == LIO_READ) {
1428 				p->p_stats->p_ru.ru_inblock += cb->inputcharge;
1429 				cb->inputcharge = 0;
1430 			}
1431 			aio_free_entry(cb);
1432 			return 0;
1433 		}
1434 	}
1435 	crit_enter();
1436 	for (cb = TAILQ_FIRST(&ki->kaio_bufdone); cb; cb = ncb) {
1437 		ncb = TAILQ_NEXT(cb, plist);
1438 		if (((intptr_t) cb->uaiocb._aiocb_private.kernelinfo)
1439 		    == jobref) {
1440 			crit_exit();
1441 			if (ujob == cb->uuaiocb) {
1442 				uap->sysmsg_result =
1443 				    cb->uaiocb._aiocb_private.status;
1444 			} else
1445 				uap->sysmsg_result = EFAULT;
1446 			aio_free_entry(cb);
1447 			return 0;
1448 		}
1449 	}
1450 	crit_exit();
1451 
1452 	return (EINVAL);
1453 #endif /* VFS_AIO */
1454 }
1455 
1456 /*
1457  * Allow a process to wakeup when any of the I/O requests are completed.
1458  */
1459 int
1460 sys_aio_suspend(struct aio_suspend_args *uap)
1461 {
1462 #ifndef VFS_AIO
1463 	return ENOSYS;
1464 #else
1465 	struct proc *p = curproc;
1466 	struct timeval atv;
1467 	struct timespec ts;
1468 	struct aiocb *const *cbptr, *cbp;
1469 	struct kaioinfo *ki;
1470 	struct aiocblist *cb;
1471 	int i;
1472 	int njoblist;
1473 	int error, timo;
1474 	long *ijoblist;
1475 	struct aiocb **ujoblist;
1476 
1477 	if (uap->nent > AIO_LISTIO_MAX)
1478 		return EINVAL;
1479 
1480 	timo = 0;
1481 	if (uap->timeout) {
1482 		/* Get timespec struct. */
1483 		if ((error = copyin(uap->timeout, &ts, sizeof(ts))) != 0)
1484 			return error;
1485 
1486 		if (ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000)
1487 			return (EINVAL);
1488 
1489 		TIMESPEC_TO_TIMEVAL(&atv, &ts);
1490 		if (itimerfix(&atv))
1491 			return (EINVAL);
1492 		timo = tvtohz_high(&atv);
1493 	}
1494 
1495 	ki = p->p_aioinfo;
1496 	if (ki == NULL)
1497 		return EAGAIN;
1498 
1499 	njoblist = 0;
1500 	ijoblist = zalloc(aiol_zone);
1501 	ujoblist = zalloc(aiol_zone);
1502 	cbptr = uap->aiocbp;
1503 
1504 	for (i = 0; i < uap->nent; i++) {
1505 		cbp = (struct aiocb *)(intptr_t)fuword(&cbptr[i]);
1506 		if (cbp == 0)
1507 			continue;
1508 		ujoblist[njoblist] = cbp;
1509 		ijoblist[njoblist] = fuword(&cbp->_aiocb_private.kernelinfo);
1510 		njoblist++;
1511 	}
1512 
1513 	if (njoblist == 0) {
1514 		zfree(aiol_zone, ijoblist);
1515 		zfree(aiol_zone, ujoblist);
1516 		return 0;
1517 	}
1518 
1519 	error = 0;
1520 	for (;;) {
1521 		TAILQ_FOREACH(cb, &ki->kaio_jobdone, plist) {
1522 			for (i = 0; i < njoblist; i++) {
1523 				if (((intptr_t)
1524 				    cb->uaiocb._aiocb_private.kernelinfo) ==
1525 				    ijoblist[i]) {
1526 					if (ujoblist[i] != cb->uuaiocb)
1527 						error = EINVAL;
1528 					zfree(aiol_zone, ijoblist);
1529 					zfree(aiol_zone, ujoblist);
1530 					return error;
1531 				}
1532 			}
1533 		}
1534 
1535 		crit_enter();
1536 		for (cb = TAILQ_FIRST(&ki->kaio_bufdone); cb; cb =
1537 		    TAILQ_NEXT(cb, plist)) {
1538 			for (i = 0; i < njoblist; i++) {
1539 				if (((intptr_t)
1540 				    cb->uaiocb._aiocb_private.kernelinfo) ==
1541 				    ijoblist[i]) {
1542 					crit_exit();
1543 					if (ujoblist[i] != cb->uuaiocb)
1544 						error = EINVAL;
1545 					zfree(aiol_zone, ijoblist);
1546 					zfree(aiol_zone, ujoblist);
1547 					return error;
1548 				}
1549 			}
1550 		}
1551 
1552 		ki->kaio_flags |= KAIO_WAKEUP;
1553 		error = tsleep(p, PCATCH, "aiospn", timo);
1554 		crit_exit();
1555 
1556 		if (error == ERESTART || error == EINTR) {
1557 			zfree(aiol_zone, ijoblist);
1558 			zfree(aiol_zone, ujoblist);
1559 			return EINTR;
1560 		} else if (error == EWOULDBLOCK) {
1561 			zfree(aiol_zone, ijoblist);
1562 			zfree(aiol_zone, ujoblist);
1563 			return EAGAIN;
1564 		}
1565 	}
1566 
1567 /* NOTREACHED */
1568 	return EINVAL;
1569 #endif /* VFS_AIO */
1570 }
1571 
1572 /*
1573  * aio_cancel cancels any non-physio aio operations not currently in
1574  * progress.
1575  */
1576 int
1577 sys_aio_cancel(struct aio_cancel_args *uap)
1578 {
1579 #ifndef VFS_AIO
1580 	return ENOSYS;
1581 #else
1582 	struct proc *p = curproc;
1583 	struct kaioinfo *ki;
1584 	struct aiocblist *cbe, *cbn;
1585 	struct file *fp;
1586 	struct filedesc *fdp;
1587 	struct socket *so;
1588 	struct proc *po;
1589 	int error;
1590 	int cancelled=0;
1591 	int notcancelled=0;
1592 	struct vnode *vp;
1593 
1594 	fdp = p->p_fd;
1595 	if ((u_int)uap->fd >= fdp->fd_nfiles ||
1596 	    (fp = fdp->fd_files[uap->fd].fp) == NULL)
1597 		return (EBADF);
1598 
1599         if (fp->f_type == DTYPE_VNODE) {
1600 		vp = (struct vnode *)fp->f_data;
1601 
1602 		if (vn_isdisk(vp,&error)) {
1603 			uap->sysmsg_result = AIO_NOTCANCELED;
1604         	        return 0;
1605 		}
1606 	} else if (fp->f_type == DTYPE_SOCKET) {
1607 		so = (struct socket *)fp->f_data;
1608 
1609 		crit_enter();
1610 
1611 		for (cbe = TAILQ_FIRST(&so->so_aiojobq); cbe; cbe = cbn) {
1612 			cbn = TAILQ_NEXT(cbe, list);
1613 			if ((uap->aiocbp == NULL) ||
1614 				(uap->aiocbp == cbe->uuaiocb) ) {
1615 				po = cbe->userproc;
1616 				ki = po->p_aioinfo;
1617 				TAILQ_REMOVE(&so->so_aiojobq, cbe, list);
1618 				TAILQ_REMOVE(&ki->kaio_sockqueue, cbe, plist);
1619 				TAILQ_INSERT_TAIL(&ki->kaio_jobdone, cbe, plist);
1620 				if (ki->kaio_flags & KAIO_WAKEUP) {
1621 					wakeup(po);
1622 				}
1623 				cbe->jobstate = JOBST_JOBFINISHED;
1624 				cbe->uaiocb._aiocb_private.status=-1;
1625 				cbe->uaiocb._aiocb_private.error=ECANCELED;
1626 				cancelled++;
1627 /* XXX cancelled, knote? */
1628 			        if (cbe->uaiocb.aio_sigevent.sigev_notify ==
1629 				    SIGEV_SIGNAL)
1630 					psignal(cbe->userproc, cbe->uaiocb.aio_sigevent.sigev_signo);
1631 				if (uap->aiocbp)
1632 					break;
1633 			}
1634 		}
1635 		crit_exit();
1636 
1637 		if ((cancelled) && (uap->aiocbp)) {
1638 			uap->sysmsg_result = AIO_CANCELED;
1639 			return 0;
1640 		}
1641 	}
1642 	ki=p->p_aioinfo;
1643 	if (ki == NULL)
1644 		goto done;
1645 	crit_enter();
1646 
1647 	for (cbe = TAILQ_FIRST(&ki->kaio_jobqueue); cbe; cbe = cbn) {
1648 		cbn = TAILQ_NEXT(cbe, plist);
1649 
1650 		if ((uap->fd == cbe->uaiocb.aio_fildes) &&
1651 		    ((uap->aiocbp == NULL ) ||
1652 		     (uap->aiocbp == cbe->uuaiocb))) {
1653 
1654 			if (cbe->jobstate == JOBST_JOBQGLOBAL) {
1655 				TAILQ_REMOVE(&aio_jobs, cbe, list);
1656                                 TAILQ_REMOVE(&ki->kaio_jobqueue, cbe, plist);
1657                                 TAILQ_INSERT_TAIL(&ki->kaio_jobdone, cbe,
1658                                     plist);
1659 				cancelled++;
1660 				ki->kaio_queue_finished_count++;
1661 				cbe->jobstate = JOBST_JOBFINISHED;
1662 				cbe->uaiocb._aiocb_private.status = -1;
1663 				cbe->uaiocb._aiocb_private.error = ECANCELED;
1664 /* XXX cancelled, knote? */
1665 			        if (cbe->uaiocb.aio_sigevent.sigev_notify ==
1666 				    SIGEV_SIGNAL)
1667 					psignal(cbe->userproc, cbe->uaiocb.aio_sigevent.sigev_signo);
1668 			} else {
1669 				notcancelled++;
1670 			}
1671 		}
1672 	}
1673 	crit_exit();
1674 done:
1675 	if (notcancelled) {
1676 		uap->sysmsg_result = AIO_NOTCANCELED;
1677 		return 0;
1678 	}
1679 	if (cancelled) {
1680 		uap->sysmsg_result = AIO_CANCELED;
1681 		return 0;
1682 	}
1683 	uap->sysmsg_result = AIO_ALLDONE;
1684 
1685 	return 0;
1686 #endif /* VFS_AIO */
1687 }
1688 
1689 /*
1690  * aio_error is implemented in the kernel level for compatibility purposes only.
1691  * For a user mode async implementation, it would be best to do it in a userland
1692  * subroutine.
1693  */
1694 int
1695 sys_aio_error(struct aio_error_args *uap)
1696 {
1697 #ifndef VFS_AIO
1698 	return ENOSYS;
1699 #else
1700 	struct proc *p = curproc;
1701 	struct aiocblist *cb;
1702 	struct kaioinfo *ki;
1703 	long jobref;
1704 
1705 	ki = p->p_aioinfo;
1706 	if (ki == NULL)
1707 		return EINVAL;
1708 
1709 	jobref = fuword(&uap->aiocbp->_aiocb_private.kernelinfo);
1710 	if ((jobref == -1) || (jobref == 0))
1711 		return EINVAL;
1712 
1713 	TAILQ_FOREACH(cb, &ki->kaio_jobdone, plist) {
1714 		if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo) ==
1715 		    jobref) {
1716 			uap->sysmsg_result = cb->uaiocb._aiocb_private.error;
1717 			return 0;
1718 		}
1719 	}
1720 
1721 	crit_enter();
1722 
1723 	for (cb = TAILQ_FIRST(&ki->kaio_jobqueue); cb; cb = TAILQ_NEXT(cb,
1724 	    plist)) {
1725 		if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo) ==
1726 		    jobref) {
1727 			uap->sysmsg_result = EINPROGRESS;
1728 			crit_exit();
1729 			return 0;
1730 		}
1731 	}
1732 
1733 	for (cb = TAILQ_FIRST(&ki->kaio_sockqueue); cb; cb = TAILQ_NEXT(cb,
1734 	    plist)) {
1735 		if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo) ==
1736 		    jobref) {
1737 			uap->sysmsg_result = EINPROGRESS;
1738 			crit_exit();
1739 			return 0;
1740 		}
1741 	}
1742 	crit_exit();
1743 
1744 	crit_enter();
1745 	for (cb = TAILQ_FIRST(&ki->kaio_bufdone); cb; cb = TAILQ_NEXT(cb,
1746 	    plist)) {
1747 		if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo) ==
1748 		    jobref) {
1749 			uap->sysmsg_result = cb->uaiocb._aiocb_private.error;
1750 			crit_exit();
1751 			return 0;
1752 		}
1753 	}
1754 
1755 	for (cb = TAILQ_FIRST(&ki->kaio_bufqueue); cb; cb = TAILQ_NEXT(cb,
1756 	    plist)) {
1757 		if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo) ==
1758 		    jobref) {
1759 			uap->sysmsg_result = EINPROGRESS;
1760 			crit_exit();
1761 			return 0;
1762 		}
1763 	}
1764 	crit_exit();
1765 
1766 #if (0)
1767 	/*
1768 	 * Hack for lio.
1769 	 */
1770 	status = fuword(&uap->aiocbp->_aiocb_private.status);
1771 	if (status == -1)
1772 		return fuword(&uap->aiocbp->_aiocb_private.error);
1773 #endif
1774 	return EINVAL;
1775 #endif /* VFS_AIO */
1776 }
1777 
1778 /* syscall - asynchronous read from a file (REALTIME) */
1779 int
1780 sys_aio_read(struct aio_read_args *uap)
1781 {
1782 #ifndef VFS_AIO
1783 	return ENOSYS;
1784 #else
1785 	return aio_aqueue(uap->aiocbp, LIO_READ);
1786 #endif /* VFS_AIO */
1787 }
1788 
1789 /* syscall - asynchronous write to a file (REALTIME) */
1790 int
1791 sys_aio_write(struct aio_write_args *uap)
1792 {
1793 #ifndef VFS_AIO
1794 	return ENOSYS;
1795 #else
1796 	return aio_aqueue(uap->aiocbp, LIO_WRITE);
1797 #endif /* VFS_AIO */
1798 }
1799 
1800 /* syscall - XXX undocumented */
1801 int
1802 sys_lio_listio(struct lio_listio_args *uap)
1803 {
1804 #ifndef VFS_AIO
1805 	return ENOSYS;
1806 #else
1807 	struct proc *p = curproc;
1808 	int nent, nentqueued;
1809 	struct aiocb *iocb, * const *cbptr;
1810 	struct aiocblist *cb;
1811 	struct kaioinfo *ki;
1812 	struct aio_liojob *lj;
1813 	int error, runningcode;
1814 	int nerror;
1815 	int i;
1816 
1817 	if ((uap->mode != LIO_NOWAIT) && (uap->mode != LIO_WAIT))
1818 		return EINVAL;
1819 
1820 	nent = uap->nent;
1821 	if (nent > AIO_LISTIO_MAX)
1822 		return EINVAL;
1823 
1824 	if (p->p_aioinfo == NULL)
1825 		aio_init_aioinfo(p);
1826 
1827 	if ((nent + num_queue_count) > max_queue_count)
1828 		return EAGAIN;
1829 
1830 	ki = p->p_aioinfo;
1831 	if ((nent + ki->kaio_queue_count) > ki->kaio_qallowed_count)
1832 		return EAGAIN;
1833 
1834 	lj = zalloc(aiolio_zone);
1835 	if (!lj)
1836 		return EAGAIN;
1837 
1838 	lj->lioj_flags = 0;
1839 	lj->lioj_buffer_count = 0;
1840 	lj->lioj_buffer_finished_count = 0;
1841 	lj->lioj_queue_count = 0;
1842 	lj->lioj_queue_finished_count = 0;
1843 	lj->lioj_ki = ki;
1844 
1845 	/*
1846 	 * Setup signal.
1847 	 */
1848 	if (uap->sig && (uap->mode == LIO_NOWAIT)) {
1849 		error = copyin(uap->sig, &lj->lioj_signal,
1850 		    sizeof(lj->lioj_signal));
1851 		if (error) {
1852 			zfree(aiolio_zone, lj);
1853 			return error;
1854 		}
1855 		if (!_SIG_VALID(lj->lioj_signal.sigev_signo)) {
1856 			zfree(aiolio_zone, lj);
1857 			return EINVAL;
1858 		}
1859 		lj->lioj_flags |= LIOJ_SIGNAL;
1860 		lj->lioj_flags &= ~LIOJ_SIGNAL_POSTED;
1861 	} else
1862 		lj->lioj_flags &= ~LIOJ_SIGNAL;
1863 
1864 	TAILQ_INSERT_TAIL(&ki->kaio_liojoblist, lj, lioj_list);
1865 	/*
1866 	 * Get pointers to the list of I/O requests.
1867 	 */
1868 	nerror = 0;
1869 	nentqueued = 0;
1870 	cbptr = uap->acb_list;
1871 	for (i = 0; i < uap->nent; i++) {
1872 		iocb = (struct aiocb *)(intptr_t)fuword(&cbptr[i]);
1873 		if (((intptr_t)iocb != -1) && ((intptr_t)iocb != 0)) {
1874 			error = _aio_aqueue(iocb, lj, 0);
1875 			if (error == 0)
1876 				nentqueued++;
1877 			else
1878 				nerror++;
1879 		}
1880 	}
1881 
1882 	/*
1883 	 * If we haven't queued any, then just return error.
1884 	 */
1885 	if (nentqueued == 0)
1886 		return 0;
1887 
1888 	/*
1889 	 * Calculate the appropriate error return.
1890 	 */
1891 	runningcode = 0;
1892 	if (nerror)
1893 		runningcode = EIO;
1894 
1895 	if (uap->mode == LIO_WAIT) {
1896 		int command, found, jobref;
1897 
1898 		for (;;) {
1899 			found = 0;
1900 			for (i = 0; i < uap->nent; i++) {
1901 				/*
1902 				 * Fetch address of the control buf pointer in
1903 				 * user space.
1904 				 */
1905 				iocb = (struct aiocb *)
1906 				    (intptr_t)fuword(&cbptr[i]);
1907 				if (((intptr_t)iocb == -1) || ((intptr_t)iocb
1908 				    == 0))
1909 					continue;
1910 
1911 				/*
1912 				 * Fetch the associated command from user space.
1913 				 */
1914 				command = fuword(&iocb->aio_lio_opcode);
1915 				if (command == LIO_NOP) {
1916 					found++;
1917 					continue;
1918 				}
1919 
1920 				jobref = fuword(&iocb->_aiocb_private.kernelinfo);
1921 
1922 				TAILQ_FOREACH(cb, &ki->kaio_jobdone, plist) {
1923 					if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo)
1924 					    == jobref) {
1925 						if (cb->uaiocb.aio_lio_opcode
1926 						    == LIO_WRITE) {
1927 							p->p_stats->p_ru.ru_oublock
1928 							    +=
1929 							    cb->outputcharge;
1930 							cb->outputcharge = 0;
1931 						} else if (cb->uaiocb.aio_lio_opcode
1932 						    == LIO_READ) {
1933 							p->p_stats->p_ru.ru_inblock
1934 							    += cb->inputcharge;
1935 							cb->inputcharge = 0;
1936 						}
1937 						found++;
1938 						break;
1939 					}
1940 				}
1941 
1942 				crit_enter();
1943 				TAILQ_FOREACH(cb, &ki->kaio_bufdone, plist) {
1944 					if (((intptr_t)cb->uaiocb._aiocb_private.kernelinfo)
1945 					    == jobref) {
1946 						found++;
1947 						break;
1948 					}
1949 				}
1950 				crit_exit();
1951 			}
1952 
1953 			/*
1954 			 * If all I/Os have been disposed of, then we can
1955 			 * return.
1956 			 */
1957 			if (found == nentqueued)
1958 				return runningcode;
1959 
1960 			ki->kaio_flags |= KAIO_WAKEUP;
1961 			error = tsleep(p, PCATCH, "aiospn", 0);
1962 
1963 			if (error == EINTR)
1964 				return EINTR;
1965 			else if (error == EWOULDBLOCK)
1966 				return EAGAIN;
1967 		}
1968 	}
1969 
1970 	return runningcode;
1971 #endif /* VFS_AIO */
1972 }
1973 
1974 #ifdef VFS_AIO
1975 /*
1976  * This is a weird hack so that we can post a signal.  It is safe to do so from
1977  * a timeout routine, but *not* from an interrupt routine.
1978  */
1979 static void
1980 process_signal(void *aioj)
1981 {
1982 	struct aiocblist *aiocbe = aioj;
1983 	struct aio_liojob *lj = aiocbe->lio;
1984 	struct aiocb *cb = &aiocbe->uaiocb;
1985 
1986 	if ((lj) && (lj->lioj_signal.sigev_notify == SIGEV_SIGNAL) &&
1987 	    (lj->lioj_queue_count == lj->lioj_queue_finished_count)) {
1988 		psignal(lj->lioj_ki->kaio_p, lj->lioj_signal.sigev_signo);
1989 		lj->lioj_flags |= LIOJ_SIGNAL_POSTED;
1990 	}
1991 
1992 	if (cb->aio_sigevent.sigev_notify == SIGEV_SIGNAL)
1993 		psignal(aiocbe->userproc, cb->aio_sigevent.sigev_signo);
1994 }
1995 
1996 /*
1997  * Interrupt handler for physio, performs the necessary process wakeups, and
1998  * signals.
1999  */
2000 static void
2001 aio_physwakeup(struct bio *bio)
2002 {
2003 	struct buf *bp = bio->bio_buf;
2004 	struct aiocblist *aiocbe;
2005 	struct proc *p;
2006 	struct kaioinfo *ki;
2007 	struct aio_liojob *lj;
2008 
2009 	aiocbe = bio->bio_caller_info2.ptr;
2010 
2011 	if (aiocbe) {
2012 		p = bio->bio_caller_info1.ptr;
2013 
2014 		aiocbe->jobstate = JOBST_JOBBFINISHED;
2015 		aiocbe->uaiocb._aiocb_private.status -= bp->b_resid;
2016 		aiocbe->uaiocb._aiocb_private.error = 0;
2017 		aiocbe->jobflags |= AIOCBLIST_DONE;
2018 
2019 		if (bp->b_flags & B_ERROR)
2020 			aiocbe->uaiocb._aiocb_private.error = bp->b_error;
2021 
2022 		lj = aiocbe->lio;
2023 		if (lj) {
2024 			lj->lioj_buffer_finished_count++;
2025 
2026 			/*
2027 			 * wakeup/signal if all of the interrupt jobs are done.
2028 			 */
2029 			if (lj->lioj_buffer_finished_count ==
2030 			    lj->lioj_buffer_count) {
2031 				/*
2032 				 * Post a signal if it is called for.
2033 				 */
2034 				if ((lj->lioj_flags &
2035 				    (LIOJ_SIGNAL|LIOJ_SIGNAL_POSTED)) ==
2036 				    LIOJ_SIGNAL) {
2037 					lj->lioj_flags |= LIOJ_SIGNAL_POSTED;
2038 					callout_reset(&aiocbe->timeout, 0,
2039 							process_signal, aiocbe);
2040 				}
2041 			}
2042 		}
2043 
2044 		ki = p->p_aioinfo;
2045 		if (ki) {
2046 			ki->kaio_buffer_finished_count++;
2047 			TAILQ_REMOVE(&aio_bufjobs, aiocbe, list);
2048 			TAILQ_REMOVE(&ki->kaio_bufqueue, aiocbe, plist);
2049 			TAILQ_INSERT_TAIL(&ki->kaio_bufdone, aiocbe, plist);
2050 
2051 			KNOTE(&aiocbe->klist, 0);
2052 			/* Do the wakeup. */
2053 			if (ki->kaio_flags & (KAIO_RUNDOWN|KAIO_WAKEUP)) {
2054 				ki->kaio_flags &= ~KAIO_WAKEUP;
2055 				wakeup(p);
2056 			}
2057 		}
2058 
2059 		if (aiocbe->uaiocb.aio_sigevent.sigev_notify == SIGEV_SIGNAL) {
2060 			callout_reset(&aiocbe->timeout, 0,
2061 					process_signal, aiocbe);
2062 		}
2063 	}
2064 	bp->b_cmd = BUF_CMD_DONE;
2065 	wakeup(bp);
2066 }
2067 #endif /* VFS_AIO */
2068 
2069 /* syscall - wait for the next completion of an aio request */
2070 int
2071 sys_aio_waitcomplete(struct aio_waitcomplete_args *uap)
2072 {
2073 #ifndef VFS_AIO
2074 	return ENOSYS;
2075 #else
2076 	struct proc *p = curproc;
2077 	struct timeval atv;
2078 	struct timespec ts;
2079 	struct kaioinfo *ki;
2080 	struct aiocblist *cb = NULL;
2081 	int error, timo;
2082 
2083 	suword(uap->aiocbp, (int)NULL);
2084 
2085 	timo = 0;
2086 	if (uap->timeout) {
2087 		/* Get timespec struct. */
2088 		error = copyin(uap->timeout, &ts, sizeof(ts));
2089 		if (error)
2090 			return error;
2091 
2092 		if ((ts.tv_nsec < 0) || (ts.tv_nsec >= 1000000000))
2093 			return (EINVAL);
2094 
2095 		TIMESPEC_TO_TIMEVAL(&atv, &ts);
2096 		if (itimerfix(&atv))
2097 			return (EINVAL);
2098 		timo = tvtohz_high(&atv);
2099 	}
2100 
2101 	ki = p->p_aioinfo;
2102 	if (ki == NULL)
2103 		return EAGAIN;
2104 
2105 	for (;;) {
2106 		if ((cb = TAILQ_FIRST(&ki->kaio_jobdone)) != 0) {
2107 			suword(uap->aiocbp, (uintptr_t)cb->uuaiocb);
2108 			uap->sysmsg_result = cb->uaiocb._aiocb_private.status;
2109 			if (cb->uaiocb.aio_lio_opcode == LIO_WRITE) {
2110 				p->p_stats->p_ru.ru_oublock +=
2111 				    cb->outputcharge;
2112 				cb->outputcharge = 0;
2113 			} else if (cb->uaiocb.aio_lio_opcode == LIO_READ) {
2114 				p->p_stats->p_ru.ru_inblock += cb->inputcharge;
2115 				cb->inputcharge = 0;
2116 			}
2117 			aio_free_entry(cb);
2118 			return cb->uaiocb._aiocb_private.error;
2119 		}
2120 
2121 		crit_enter();
2122  		if ((cb = TAILQ_FIRST(&ki->kaio_bufdone)) != 0 ) {
2123 			crit_exit();
2124 			suword(uap->aiocbp, (uintptr_t)cb->uuaiocb);
2125 			uap->sysmsg_result = cb->uaiocb._aiocb_private.status;
2126 			aio_free_entry(cb);
2127 			return cb->uaiocb._aiocb_private.error;
2128 		}
2129 
2130 		ki->kaio_flags |= KAIO_WAKEUP;
2131 		error = tsleep(p, PCATCH, "aiowc", timo);
2132 		crit_exit();
2133 
2134 		if (error == ERESTART)
2135 			return EINTR;
2136 		else if (error < 0)
2137 			return error;
2138 		else if (error == EINTR)
2139 			return EINTR;
2140 		else if (error == EWOULDBLOCK)
2141 			return EAGAIN;
2142 	}
2143 #endif /* VFS_AIO */
2144 }
2145 
2146 #ifndef VFS_AIO
2147 static int
2148 filt_aioattach(struct knote *kn)
2149 {
2150 
2151 	return (ENXIO);
2152 }
2153 
2154 struct filterops aio_filtops =
2155 	{ 0, filt_aioattach, NULL, NULL };
2156 
2157 #else
2158 /* kqueue attach function */
2159 static int
2160 filt_aioattach(struct knote *kn)
2161 {
2162 	struct aiocblist *aiocbe = (struct aiocblist *)kn->kn_sdata;
2163 
2164 	/*
2165 	 * The aiocbe pointer must be validated before using it, so
2166 	 * registration is restricted to the kernel; the user cannot
2167 	 * set EV_FLAG1.
2168 	 */
2169 	if ((kn->kn_flags & EV_FLAG1) == 0)
2170 		return (EPERM);
2171 	kn->kn_flags &= ~EV_FLAG1;
2172 
2173 	SLIST_INSERT_HEAD(&aiocbe->klist, kn, kn_selnext);
2174 
2175 	return (0);
2176 }
2177 
2178 /* kqueue detach function */
2179 static void
2180 filt_aiodetach(struct knote *kn)
2181 {
2182 	struct aiocblist *aiocbe = (struct aiocblist *)kn->kn_sdata;
2183 
2184 	SLIST_REMOVE(&aiocbe->klist, kn, knote, kn_selnext);
2185 }
2186 
2187 /* kqueue filter function */
2188 /*ARGSUSED*/
2189 static int
2190 filt_aio(struct knote *kn, long hint)
2191 {
2192 	struct aiocblist *aiocbe = (struct aiocblist *)kn->kn_sdata;
2193 
2194 	kn->kn_data = aiocbe->uaiocb._aiocb_private.error;
2195 	if (aiocbe->jobstate != JOBST_JOBFINISHED &&
2196 	    aiocbe->jobstate != JOBST_JOBBFINISHED)
2197 		return (0);
2198 	kn->kn_flags |= EV_EOF;
2199 	return (1);
2200 }
2201 
2202 struct filterops aio_filtops =
2203 	{ 0, filt_aioattach, filt_aiodetach, filt_aio };
2204 #endif /* VFS_AIO */
2205