blob: 55991e4132a7f30f778a7f86862b8992c59bafca [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * An async IO implementation for Linux
3 * Written by Benjamin LaHaise <bcrl@kvack.org>
4 *
5 * Implements an efficient asynchronous io interface.
6 *
7 * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
8 *
9 * See ../COPYING for licensing terms.
10 */
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/aio_abi.h>
16#include <linux/module.h>
17#include <linux/syscalls.h>
Badari Pulavarty027445c2006-09-30 23:28:46 -070018#include <linux/uio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20#define DEBUG 0
21
22#include <linux/sched.h>
23#include <linux/fs.h>
24#include <linux/file.h>
25#include <linux/mm.h>
26#include <linux/mman.h>
27#include <linux/slab.h>
28#include <linux/timer.h>
29#include <linux/aio.h>
30#include <linux/highmem.h>
31#include <linux/workqueue.h>
32#include <linux/security.h>
33
34#include <asm/kmap_types.h>
35#include <asm/uaccess.h>
36#include <asm/mmu_context.h>
37
38#if DEBUG > 1
39#define dprintk printk
40#else
41#define dprintk(x...) do { ; } while (0)
42#endif
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044/*------ sysctl variables----*/
Zach Brownd55b5fd2005-11-07 00:59:31 -080045static DEFINE_SPINLOCK(aio_nr_lock);
46unsigned long aio_nr; /* current system wide number of aio requests */
47unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
Linus Torvalds1da177e2005-04-16 15:20:36 -070048/*----end sysctl variables---*/
49
Christoph Lametere18b8902006-12-06 20:33:20 -080050static struct kmem_cache *kiocb_cachep;
51static struct kmem_cache *kioctx_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53static struct workqueue_struct *aio_wq;
54
55/* Used for rare fput completion. */
David Howells65f27f32006-11-22 14:55:48 +000056static void aio_fput_routine(struct work_struct *);
57static DECLARE_WORK(fput_work, aio_fput_routine);
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59static DEFINE_SPINLOCK(fput_lock);
Adrian Bunk25ee7e32005-04-25 08:18:14 -070060static LIST_HEAD(fput_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
David Howells65f27f32006-11-22 14:55:48 +000062static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070063static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65/* aio_setup
66 * Creates the slab caches used by the aio routines, panic on
67 * failure as this is done early during the boot sequence.
68 */
69static int __init aio_setup(void)
70{
71 kiocb_cachep = kmem_cache_create("kiocb", sizeof(struct kiocb),
72 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
73 kioctx_cachep = kmem_cache_create("kioctx", sizeof(struct kioctx),
74 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
75
76 aio_wq = create_workqueue("aio");
77
78 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
79
80 return 0;
81}
82
83static void aio_free_ring(struct kioctx *ctx)
84{
85 struct aio_ring_info *info = &ctx->ring_info;
86 long i;
87
88 for (i=0; i<info->nr_pages; i++)
89 put_page(info->ring_pages[i]);
90
91 if (info->mmap_size) {
92 down_write(&ctx->mm->mmap_sem);
93 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
94 up_write(&ctx->mm->mmap_sem);
95 }
96
97 if (info->ring_pages && info->ring_pages != info->internal_pages)
98 kfree(info->ring_pages);
99 info->ring_pages = NULL;
100 info->nr = 0;
101}
102
103static int aio_setup_ring(struct kioctx *ctx)
104{
105 struct aio_ring *ring;
106 struct aio_ring_info *info = &ctx->ring_info;
107 unsigned nr_events = ctx->max_reqs;
108 unsigned long size;
109 int nr_pages;
110
111 /* Compensate for the ring buffer's head/tail overlap entry */
112 nr_events += 2; /* 1 is required, 2 for good luck */
113
114 size = sizeof(struct aio_ring);
115 size += sizeof(struct io_event) * nr_events;
116 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
117
118 if (nr_pages < 0)
119 return -EINVAL;
120
121 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
122
123 info->nr = 0;
124 info->ring_pages = info->internal_pages;
125 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800126 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 if (!info->ring_pages)
128 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 }
130
131 info->mmap_size = nr_pages * PAGE_SIZE;
132 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
133 down_write(&ctx->mm->mmap_sem);
134 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
135 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE,
136 0);
137 if (IS_ERR((void *)info->mmap_base)) {
138 up_write(&ctx->mm->mmap_sem);
139 printk("mmap err: %ld\n", -info->mmap_base);
140 info->mmap_size = 0;
141 aio_free_ring(ctx);
142 return -EAGAIN;
143 }
144
145 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
146 info->nr_pages = get_user_pages(current, ctx->mm,
147 info->mmap_base, nr_pages,
148 1, 0, info->ring_pages, NULL);
149 up_write(&ctx->mm->mmap_sem);
150
151 if (unlikely(info->nr_pages != nr_pages)) {
152 aio_free_ring(ctx);
153 return -EAGAIN;
154 }
155
156 ctx->user_id = info->mmap_base;
157
158 info->nr = nr_events; /* trusted copy */
159
160 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
161 ring->nr = nr_events; /* user copy */
162 ring->id = ctx->user_id;
163 ring->head = ring->tail = 0;
164 ring->magic = AIO_RING_MAGIC;
165 ring->compat_features = AIO_RING_COMPAT_FEATURES;
166 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
167 ring->header_length = sizeof(struct aio_ring);
168 kunmap_atomic(ring, KM_USER0);
169
170 return 0;
171}
172
173
174/* aio_ring_event: returns a pointer to the event at the given index from
175 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
176 */
177#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
178#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
179#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
180
181#define aio_ring_event(info, nr, km) ({ \
182 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
183 struct io_event *__event; \
184 __event = kmap_atomic( \
185 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
186 __event += pos % AIO_EVENTS_PER_PAGE; \
187 __event; \
188})
189
190#define put_aio_ring_event(event, km) do { \
191 struct io_event *__event = (event); \
192 (void)__event; \
193 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
194} while(0)
195
196/* ioctx_alloc
197 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
198 */
199static struct kioctx *ioctx_alloc(unsigned nr_events)
200{
201 struct mm_struct *mm;
202 struct kioctx *ctx;
203
204 /* Prevent overflows */
205 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
206 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
207 pr_debug("ENOMEM: nr_events too high\n");
208 return ERR_PTR(-EINVAL);
209 }
210
Zach Brownd55b5fd2005-11-07 00:59:31 -0800211 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 return ERR_PTR(-EAGAIN);
213
214 ctx = kmem_cache_alloc(kioctx_cachep, GFP_KERNEL);
215 if (!ctx)
216 return ERR_PTR(-ENOMEM);
217
218 memset(ctx, 0, sizeof(*ctx));
219 ctx->max_reqs = nr_events;
220 mm = ctx->mm = current->mm;
221 atomic_inc(&mm->mm_count);
222
223 atomic_set(&ctx->users, 1);
224 spin_lock_init(&ctx->ctx_lock);
225 spin_lock_init(&ctx->ring_info.ring_lock);
226 init_waitqueue_head(&ctx->wait);
227
228 INIT_LIST_HEAD(&ctx->active_reqs);
229 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000230 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
232 if (aio_setup_ring(ctx) < 0)
233 goto out_freectx;
234
235 /* limit the number of system wide aios */
Zach Brownd55b5fd2005-11-07 00:59:31 -0800236 spin_lock(&aio_nr_lock);
237 if (aio_nr + ctx->max_reqs > aio_max_nr ||
238 aio_nr + ctx->max_reqs < aio_nr)
239 ctx->max_reqs = 0;
240 else
241 aio_nr += ctx->max_reqs;
242 spin_unlock(&aio_nr_lock);
243 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 goto out_cleanup;
245
246 /* now link into global list. kludge. FIXME */
247 write_lock(&mm->ioctx_list_lock);
248 ctx->next = mm->ioctx_list;
249 mm->ioctx_list = ctx;
250 write_unlock(&mm->ioctx_list_lock);
251
252 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
253 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
254 return ctx;
255
256out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 __put_ioctx(ctx);
258 return ERR_PTR(-EAGAIN);
259
260out_freectx:
261 mmdrop(mm);
262 kmem_cache_free(kioctx_cachep, ctx);
263 ctx = ERR_PTR(-ENOMEM);
264
265 dprintk("aio: error allocating ioctx %p\n", ctx);
266 return ctx;
267}
268
269/* aio_cancel_all
270 * Cancels all outstanding aio requests on an aio context. Used
271 * when the processes owning a context have all exited to encourage
272 * the rapid destruction of the kioctx.
273 */
274static void aio_cancel_all(struct kioctx *ctx)
275{
276 int (*cancel)(struct kiocb *, struct io_event *);
277 struct io_event res;
278 spin_lock_irq(&ctx->ctx_lock);
279 ctx->dead = 1;
280 while (!list_empty(&ctx->active_reqs)) {
281 struct list_head *pos = ctx->active_reqs.next;
282 struct kiocb *iocb = list_kiocb(pos);
283 list_del_init(&iocb->ki_list);
284 cancel = iocb->ki_cancel;
285 kiocbSetCancelled(iocb);
286 if (cancel) {
287 iocb->ki_users++;
288 spin_unlock_irq(&ctx->ctx_lock);
289 cancel(iocb, &res);
290 spin_lock_irq(&ctx->ctx_lock);
291 }
292 }
293 spin_unlock_irq(&ctx->ctx_lock);
294}
295
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700296static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297{
298 struct task_struct *tsk = current;
299 DECLARE_WAITQUEUE(wait, tsk);
300
Ken Chendee11c22007-02-03 01:13:45 -0800301 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800303 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
305 add_wait_queue(&ctx->wait, &wait);
306 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
307 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800308 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 schedule();
310 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800311 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 }
313 __set_task_state(tsk, TASK_RUNNING);
314 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800315
316out:
317 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318}
319
320/* wait_on_sync_kiocb:
321 * Waits on the given sync kiocb to complete.
322 */
323ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb)
324{
325 while (iocb->ki_users) {
326 set_current_state(TASK_UNINTERRUPTIBLE);
327 if (!iocb->ki_users)
328 break;
329 schedule();
330 }
331 __set_current_state(TASK_RUNNING);
332 return iocb->ki_user_data;
333}
334
335/* exit_aio: called when the last user of mm goes away. At this point,
336 * there is no way for any new requests to be submited or any of the
337 * io_* syscalls to be called on the context. However, there may be
338 * outstanding requests which hold references to the context; as they
339 * go away, they will call put_ioctx and release any pinned memory
340 * associated with the request (held via struct page * references).
341 */
342void fastcall exit_aio(struct mm_struct *mm)
343{
344 struct kioctx *ctx = mm->ioctx_list;
345 mm->ioctx_list = NULL;
346 while (ctx) {
347 struct kioctx *next = ctx->next;
348 ctx->next = NULL;
349 aio_cancel_all(ctx);
350
351 wait_for_all_aios(ctx);
352 /*
353 * this is an overkill, but ensures we don't leave
354 * the ctx on the aio_wq
355 */
356 flush_workqueue(aio_wq);
357
358 if (1 != atomic_read(&ctx->users))
359 printk(KERN_DEBUG
360 "exit_aio:ioctx still alive: %d %d %d\n",
361 atomic_read(&ctx->users), ctx->dead,
362 ctx->reqs_active);
363 put_ioctx(ctx);
364 ctx = next;
365 }
366}
367
368/* __put_ioctx
369 * Called when the last user of an aio context has gone away,
370 * and the struct needs to be freed.
371 */
372void fastcall __put_ioctx(struct kioctx *ctx)
373{
374 unsigned nr_events = ctx->max_reqs;
375
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100376 BUG_ON(ctx->reqs_active);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
378 cancel_delayed_work(&ctx->wq);
379 flush_workqueue(aio_wq);
380 aio_free_ring(ctx);
381 mmdrop(ctx->mm);
382 ctx->mm = NULL;
383 pr_debug("__put_ioctx: freeing %p\n", ctx);
384 kmem_cache_free(kioctx_cachep, ctx);
385
Zach Brownd55b5fd2005-11-07 00:59:31 -0800386 if (nr_events) {
387 spin_lock(&aio_nr_lock);
388 BUG_ON(aio_nr - nr_events > aio_nr);
389 aio_nr -= nr_events;
390 spin_unlock(&aio_nr_lock);
391 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392}
393
394/* aio_get_req
395 * Allocate a slot for an aio request. Increments the users count
396 * of the kioctx so that the kioctx stays around until all requests are
397 * complete. Returns NULL if no requests are free.
398 *
399 * Returns with kiocb->users set to 2. The io submit code path holds
400 * an extra reference while submitting the i/o.
401 * This prevents races between the aio code path referencing the
402 * req (after submitting it) and aio_complete() freeing the req.
403 */
404static struct kiocb *FASTCALL(__aio_get_req(struct kioctx *ctx));
405static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx)
406{
407 struct kiocb *req = NULL;
408 struct aio_ring *ring;
409 int okay = 0;
410
411 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
412 if (unlikely(!req))
413 return NULL;
414
Zach Brown4faa5282005-10-17 16:43:33 -0700415 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 req->ki_users = 2;
417 req->ki_key = 0;
418 req->ki_ctx = ctx;
419 req->ki_cancel = NULL;
420 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 req->ki_dtor = NULL;
422 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700423 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 INIT_LIST_HEAD(&req->ki_run_list);
425
426 /* Check if the completion queue has enough free space to
427 * accept an event from this io.
428 */
429 spin_lock_irq(&ctx->ctx_lock);
430 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
431 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
432 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 ctx->reqs_active++;
434 okay = 1;
435 }
436 kunmap_atomic(ring, KM_USER0);
437 spin_unlock_irq(&ctx->ctx_lock);
438
439 if (!okay) {
440 kmem_cache_free(kiocb_cachep, req);
441 req = NULL;
442 }
443
444 return req;
445}
446
447static inline struct kiocb *aio_get_req(struct kioctx *ctx)
448{
449 struct kiocb *req;
450 /* Handle a potential starvation case -- should be exceedingly rare as
451 * requests will be stuck on fput_head only if the aio_fput_routine is
452 * delayed and the requests were the last user of the struct file.
453 */
454 req = __aio_get_req(ctx);
455 if (unlikely(NULL == req)) {
456 aio_fput_routine(NULL);
457 req = __aio_get_req(ctx);
458 }
459 return req;
460}
461
462static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
463{
Zach Brownd00689a2005-11-13 16:07:34 -0800464 assert_spin_locked(&ctx->ctx_lock);
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 if (req->ki_dtor)
467 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700468 if (req->ki_iovec != &req->ki_inline_vec)
469 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 kmem_cache_free(kiocb_cachep, req);
471 ctx->reqs_active--;
472
473 if (unlikely(!ctx->reqs_active && ctx->dead))
474 wake_up(&ctx->wait);
475}
476
David Howells65f27f32006-11-22 14:55:48 +0000477static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
479 spin_lock_irq(&fput_lock);
480 while (likely(!list_empty(&fput_head))) {
481 struct kiocb *req = list_kiocb(fput_head.next);
482 struct kioctx *ctx = req->ki_ctx;
483
484 list_del(&req->ki_list);
485 spin_unlock_irq(&fput_lock);
486
487 /* Complete the fput */
488 __fput(req->ki_filp);
489
490 /* Link the iocb into the context's free list */
491 spin_lock_irq(&ctx->ctx_lock);
492 really_put_req(ctx, req);
493 spin_unlock_irq(&ctx->ctx_lock);
494
495 put_ioctx(ctx);
496 spin_lock_irq(&fput_lock);
497 }
498 spin_unlock_irq(&fput_lock);
499}
500
501/* __aio_put_req
502 * Returns true if this put was the last user of the request.
503 */
504static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
505{
506 dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
507 req, atomic_read(&req->ki_filp->f_count));
508
Zach Brownd00689a2005-11-13 16:07:34 -0800509 assert_spin_locked(&ctx->ctx_lock);
510
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 req->ki_users --;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100512 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 if (likely(req->ki_users))
514 return 0;
515 list_del(&req->ki_list); /* remove from active_reqs */
516 req->ki_cancel = NULL;
517 req->ki_retry = NULL;
518
519 /* Must be done under the lock to serialise against cancellation.
520 * Call this aio_fput as it duplicates fput via the fput_work.
521 */
Nick Piggin095975d2006-01-08 01:02:19 -0800522 if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 get_ioctx(ctx);
524 spin_lock(&fput_lock);
525 list_add(&req->ki_list, &fput_head);
526 spin_unlock(&fput_lock);
527 queue_work(aio_wq, &fput_work);
528 } else
529 really_put_req(ctx, req);
530 return 1;
531}
532
533/* aio_put_req
534 * Returns true if this put was the last user of the kiocb,
535 * false if the request is still in use.
536 */
537int fastcall aio_put_req(struct kiocb *req)
538{
539 struct kioctx *ctx = req->ki_ctx;
540 int ret;
541 spin_lock_irq(&ctx->ctx_lock);
542 ret = __aio_put_req(ctx, req);
543 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 return ret;
545}
546
547/* Lookup an ioctx id. ioctx_list is lockless for reads.
548 * FIXME: this is O(n) and is only suitable for development.
549 */
550struct kioctx *lookup_ioctx(unsigned long ctx_id)
551{
552 struct kioctx *ioctx;
553 struct mm_struct *mm;
554
555 mm = current->mm;
556 read_lock(&mm->ioctx_list_lock);
557 for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next)
558 if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) {
559 get_ioctx(ioctx);
560 break;
561 }
562 read_unlock(&mm->ioctx_list_lock);
563
564 return ioctx;
565}
566
567/*
568 * use_mm
569 * Makes the calling kernel thread take on the specified
570 * mm context.
571 * Called by the retry thread execute retries within the
572 * iocb issuer's mm context, so that copy_from/to_user
573 * operations work seamlessly for aio.
574 * (Note: this routine is intended to be called only
575 * from a kernel thread context)
576 */
577static void use_mm(struct mm_struct *mm)
578{
579 struct mm_struct *active_mm;
580 struct task_struct *tsk = current;
581
582 task_lock(tsk);
583 tsk->flags |= PF_BORROWED_MM;
584 active_mm = tsk->active_mm;
585 atomic_inc(&mm->mm_count);
586 tsk->mm = mm;
587 tsk->active_mm = mm;
Paolo 'Blaisorblade' Giarrusso1e40cd32005-09-03 15:57:25 -0700588 /*
589 * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
590 * it won't work. Update it accordingly if you change it here
591 */
Jeremy Fitzhardinge90aef122006-12-13 00:34:49 -0800592 switch_mm(active_mm, mm, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 task_unlock(tsk);
594
595 mmdrop(active_mm);
596}
597
598/*
599 * unuse_mm
600 * Reverses the effect of use_mm, i.e. releases the
601 * specified mm context which was earlier taken on
602 * by the calling kernel thread
603 * (Note: this routine is intended to be called only
604 * from a kernel thread context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700606static void unuse_mm(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607{
608 struct task_struct *tsk = current;
609
610 task_lock(tsk);
611 tsk->flags &= ~PF_BORROWED_MM;
612 tsk->mm = NULL;
613 /* active_mm is still 'mm' */
614 enter_lazy_tlb(mm, tsk);
615 task_unlock(tsk);
616}
617
618/*
619 * Queue up a kiocb to be retried. Assumes that the kiocb
620 * has already been marked as kicked, and places it on
621 * the retry run list for the corresponding ioctx, if it
622 * isn't already queued. Returns 1 if it actually queued
623 * the kiocb (to tell the caller to activate the work
624 * queue to process it), or 0, if it found that it was
625 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 */
627static inline int __queue_kicked_iocb(struct kiocb *iocb)
628{
629 struct kioctx *ctx = iocb->ki_ctx;
630
Zach Brownd00689a2005-11-13 16:07:34 -0800631 assert_spin_locked(&ctx->ctx_lock);
632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if (list_empty(&iocb->ki_run_list)) {
634 list_add_tail(&iocb->ki_run_list,
635 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 return 1;
637 }
638 return 0;
639}
640
641/* aio_run_iocb
642 * This is the core aio execution routine. It is
643 * invoked both for initial i/o submission and
644 * subsequent retries via the aio_kick_handler.
645 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200646 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 * as needed during processing.
648 *
649 * Calls the iocb retry method (already setup for the
650 * iocb on initial submission) for operation specific
651 * handling, but takes care of most of common retry
652 * execution details for a given iocb. The retry method
653 * needs to be non-blocking as far as possible, to avoid
654 * holding up other iocbs waiting to be serviced by the
655 * retry kernel thread.
656 *
657 * The trickier parts in this code have to do with
658 * ensuring that only one retry instance is in progress
659 * for a given iocb at any time. Providing that guarantee
660 * simplifies the coding of individual aio operations as
661 * it avoids various potential races.
662 */
663static ssize_t aio_run_iocb(struct kiocb *iocb)
664{
665 struct kioctx *ctx = iocb->ki_ctx;
666 ssize_t (*retry)(struct kiocb *);
667 ssize_t ret;
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 if (!(retry = iocb->ki_retry)) {
670 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
671 return 0;
672 }
673
674 /*
675 * We don't want the next retry iteration for this
676 * operation to start until this one has returned and
677 * updated the iocb state. However, wait_queue functions
678 * can trigger a kick_iocb from interrupt context in the
679 * meantime, indicating that data is available for the next
680 * iteration. We want to remember that and enable the
681 * next retry iteration _after_ we are through with
682 * this one.
683 *
684 * So, in order to be able to register a "kick", but
685 * prevent it from being queued now, we clear the kick
686 * flag, but make the kick code *think* that the iocb is
687 * still on the run list until we are actually done.
688 * When we are done with this iteration, we check if
689 * the iocb was kicked in the meantime and if so, queue
690 * it up afresh.
691 */
692
693 kiocbClearKicked(iocb);
694
695 /*
696 * This is so that aio_complete knows it doesn't need to
697 * pull the iocb off the run list (We can't just call
698 * INIT_LIST_HEAD because we don't want a kick_iocb to
699 * queue this on the run list yet)
700 */
701 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
702 spin_unlock_irq(&ctx->ctx_lock);
703
704 /* Quit retrying if the i/o has been cancelled */
705 if (kiocbIsCancelled(iocb)) {
706 ret = -EINTR;
707 aio_complete(iocb, ret, 0);
708 /* must not access the iocb after this */
709 goto out;
710 }
711
712 /*
713 * Now we are all set to call the retry method in async
714 * context. By setting this thread's io_wait context
715 * to point to the wait queue entry inside the currently
716 * running iocb for the duration of the retry, we ensure
717 * that async notification wakeups are queued by the
718 * operation instead of blocking waits, and when notified,
719 * cause the iocb to be kicked for continuation (through
720 * the aio_wake_function callback).
721 */
722 BUG_ON(current->io_wait != NULL);
723 current->io_wait = &iocb->ki_wait;
724 ret = retry(iocb);
725 current->io_wait = NULL;
726
Zach Brown897f15f2005-09-30 11:58:55 -0700727 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
728 BUG_ON(!list_empty(&iocb->ki_wait.task_list));
729 aio_complete(iocb, ret, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 }
731out:
732 spin_lock_irq(&ctx->ctx_lock);
733
734 if (-EIOCBRETRY == ret) {
735 /*
736 * OK, now that we are done with this iteration
737 * and know that there is more left to go,
738 * this is where we let go so that a subsequent
739 * "kick" can start the next iteration
740 */
741
742 /* will make __queue_kicked_iocb succeed from here on */
743 INIT_LIST_HEAD(&iocb->ki_run_list);
744 /* we must queue the next iteration ourselves, if it
745 * has already been kicked */
746 if (kiocbIsKicked(iocb)) {
747 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700748
749 /*
750 * __queue_kicked_iocb will always return 1 here, because
751 * iocb->ki_run_list is empty at this point so it should
752 * be safe to unconditionally queue the context into the
753 * work queue.
754 */
755 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 }
757 }
758 return ret;
759}
760
761/*
762 * __aio_run_iocbs:
763 * Process all pending retries queued on the ioctx
764 * run list.
765 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800766 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 */
768static int __aio_run_iocbs(struct kioctx *ctx)
769{
770 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700771 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772
Zach Brownd00689a2005-11-13 16:07:34 -0800773 assert_spin_locked(&ctx->ctx_lock);
774
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700775 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 while (!list_empty(&run_list)) {
777 iocb = list_entry(run_list.next, struct kiocb,
778 ki_run_list);
779 list_del(&iocb->ki_run_list);
780 /*
781 * Hold an extra reference while retrying i/o.
782 */
783 iocb->ki_users++; /* grab extra reference */
784 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800785 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 if (!list_empty(&ctx->run_list))
788 return 1;
789 return 0;
790}
791
792static void aio_queue_work(struct kioctx * ctx)
793{
794 unsigned long timeout;
795 /*
796 * if someone is waiting, get the work started right
797 * away, otherwise, use a longer delay
798 */
799 smp_mb();
800 if (waitqueue_active(&ctx->wait))
801 timeout = 1;
802 else
803 timeout = HZ/10;
804 queue_delayed_work(aio_wq, &ctx->wq, timeout);
805}
806
807
808/*
809 * aio_run_iocbs:
810 * Process all pending retries queued on the ioctx
811 * run list.
812 * Assumes it is operating within the aio issuer's mm
813 * context.
814 */
815static inline void aio_run_iocbs(struct kioctx *ctx)
816{
817 int requeue;
818
819 spin_lock_irq(&ctx->ctx_lock);
820
821 requeue = __aio_run_iocbs(ctx);
822 spin_unlock_irq(&ctx->ctx_lock);
823 if (requeue)
824 aio_queue_work(ctx);
825}
826
827/*
828 * just like aio_run_iocbs, but keeps running them until
829 * the list stays empty
830 */
831static inline void aio_run_all_iocbs(struct kioctx *ctx)
832{
833 spin_lock_irq(&ctx->ctx_lock);
834 while (__aio_run_iocbs(ctx))
835 ;
836 spin_unlock_irq(&ctx->ctx_lock);
837}
838
839/*
840 * aio_kick_handler:
841 * Work queue handler triggered to process pending
842 * retries on an ioctx. Takes on the aio issuer's
843 * mm context before running the iocbs, so that
844 * copy_xxx_user operates on the issuer's address
845 * space.
846 * Run on aiod's context.
847 */
David Howells65f27f32006-11-22 14:55:48 +0000848static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849{
David Howells65f27f32006-11-22 14:55:48 +0000850 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800852 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 int requeue;
854
855 set_fs(USER_DS);
856 use_mm(ctx->mm);
857 spin_lock_irq(&ctx->ctx_lock);
858 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800859 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800861 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 set_fs(oldfs);
863 /*
864 * we're in a worker thread already, don't use queue_delayed_work,
865 */
866 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000867 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868}
869
870
871/*
872 * Called by kick_iocb to queue the kiocb for retry
873 * and if required activate the aio work queue to process
874 * it
875 */
Zach Brown998765e2005-09-30 11:58:54 -0700876static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877{
878 struct kioctx *ctx = iocb->ki_ctx;
879 unsigned long flags;
880 int run = 0;
881
Zach Brown998765e2005-09-30 11:58:54 -0700882 /* We're supposed to be the only path putting the iocb back on the run
883 * list. If we find that the iocb is *back* on a wait queue already
884 * than retry has happened before we could queue the iocb. This also
885 * means that the retry could have completed and freed our iocb, no
886 * good. */
887 BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888
889 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700890 /* set this inside the lock so that we can't race with aio_run_iocb()
891 * testing it and putting the iocb on the run list under the lock */
892 if (!kiocbTryKick(iocb))
893 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700895 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897}
898
899/*
900 * kick_iocb:
901 * Called typically from a wait queue callback context
902 * (aio_wake_function) to trigger a retry of the iocb.
903 * The retry is usually executed by aio workqueue
904 * threads (See aio_kick_handler).
905 */
906void fastcall kick_iocb(struct kiocb *iocb)
907{
908 /* sync iocbs are easy: they can only ever be executing from a
909 * single context. */
910 if (is_sync_kiocb(iocb)) {
911 kiocbSetKicked(iocb);
912 wake_up_process(iocb->ki_obj.tsk);
913 return;
914 }
915
Zach Brown998765e2005-09-30 11:58:54 -0700916 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917}
918EXPORT_SYMBOL(kick_iocb);
919
920/* aio_complete
921 * Called when the io request on the given iocb is complete.
922 * Returns true if this is the last user of the request. The
923 * only other user of the request can be the cancellation code.
924 */
925int fastcall aio_complete(struct kiocb *iocb, long res, long res2)
926{
927 struct kioctx *ctx = iocb->ki_ctx;
928 struct aio_ring_info *info;
929 struct aio_ring *ring;
930 struct io_event *event;
931 unsigned long flags;
932 unsigned long tail;
933 int ret;
934
Zach Brown20dcae32005-11-13 16:07:33 -0800935 /*
936 * Special case handling for sync iocbs:
937 * - events go directly into the iocb for fast handling
938 * - the sync task with the iocb in its stack holds the single iocb
939 * ref, no other paths have a way to get another ref
940 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 */
942 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800943 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800945 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800947 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 }
949
950 info = &ctx->ring_info;
951
952 /* add a completion event to the ring buffer.
953 * must be done holding ctx->ctx_lock to prevent
954 * other code from messing with the tail
955 * pointer since we might be called from irq
956 * context.
957 */
958 spin_lock_irqsave(&ctx->ctx_lock, flags);
959
960 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
961 list_del_init(&iocb->ki_run_list);
962
963 /*
964 * cancelled requests don't get events, userland was given one
965 * when the event got cancelled.
966 */
967 if (kiocbIsCancelled(iocb))
968 goto put_rq;
969
970 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
971
972 tail = info->tail;
973 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700974 if (++tail >= info->nr)
975 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976
977 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
978 event->data = iocb->ki_user_data;
979 event->res = res;
980 event->res2 = res2;
981
982 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
983 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
984 res, res2);
985
986 /* after flagging the request as done, we
987 * must never even look at it again
988 */
989 smp_wmb(); /* make event visible before updating tail */
990
991 info->tail = tail;
992 ring->tail = tail;
993
994 put_aio_ring_event(event, KM_IRQ0);
995 kunmap_atomic(ring, KM_IRQ1);
996
997 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998put_rq:
999 /* everything turned out well, dispose of the aiocb. */
1000 ret = __aio_put_req(ctx, iocb);
1001
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 if (waitqueue_active(&ctx->wait))
1003 wake_up(&ctx->wait);
1004
Ken Chendee11c22007-02-03 01:13:45 -08001005 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 return ret;
1007}
1008
1009/* aio_read_evt
1010 * Pull an event off of the ioctx's event ring. Returns the number of
1011 * events fetched (0 or 1 ;-)
1012 * FIXME: make this use cmpxchg.
1013 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1014 */
1015static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1016{
1017 struct aio_ring_info *info = &ioctx->ring_info;
1018 struct aio_ring *ring;
1019 unsigned long head;
1020 int ret = 0;
1021
1022 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1023 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1024 (unsigned long)ring->head, (unsigned long)ring->tail,
1025 (unsigned long)ring->nr);
1026
1027 if (ring->head == ring->tail)
1028 goto out;
1029
1030 spin_lock(&info->ring_lock);
1031
1032 head = ring->head % info->nr;
1033 if (head != ring->tail) {
1034 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1035 *ent = *evp;
1036 head = (head + 1) % info->nr;
1037 smp_mb(); /* finish reading the event before updatng the head */
1038 ring->head = head;
1039 ret = 1;
1040 put_aio_ring_event(evp, KM_USER1);
1041 }
1042 spin_unlock(&info->ring_lock);
1043
1044out:
1045 kunmap_atomic(ring, KM_USER0);
1046 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1047 (unsigned long)ring->head, (unsigned long)ring->tail);
1048 return ret;
1049}
1050
1051struct aio_timeout {
1052 struct timer_list timer;
1053 int timed_out;
1054 struct task_struct *p;
1055};
1056
1057static void timeout_func(unsigned long data)
1058{
1059 struct aio_timeout *to = (struct aio_timeout *)data;
1060
1061 to->timed_out = 1;
1062 wake_up_process(to->p);
1063}
1064
1065static inline void init_timeout(struct aio_timeout *to)
1066{
1067 init_timer(&to->timer);
1068 to->timer.data = (unsigned long)to;
1069 to->timer.function = timeout_func;
1070 to->timed_out = 0;
1071 to->p = current;
1072}
1073
1074static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1075 const struct timespec *ts)
1076{
1077 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1078 if (time_after(to->timer.expires, jiffies))
1079 add_timer(&to->timer);
1080 else
1081 to->timed_out = 1;
1082}
1083
1084static inline void clear_timeout(struct aio_timeout *to)
1085{
1086 del_singleshot_timer_sync(&to->timer);
1087}
1088
1089static int read_events(struct kioctx *ctx,
1090 long min_nr, long nr,
1091 struct io_event __user *event,
1092 struct timespec __user *timeout)
1093{
1094 long start_jiffies = jiffies;
1095 struct task_struct *tsk = current;
1096 DECLARE_WAITQUEUE(wait, tsk);
1097 int ret;
1098 int i = 0;
1099 struct io_event ent;
1100 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 int retry = 0;
1102
1103 /* needed to zero any padding within an entry (there shouldn't be
1104 * any, but C is fun!
1105 */
1106 memset(&ent, 0, sizeof(ent));
1107retry:
1108 ret = 0;
1109 while (likely(i < nr)) {
1110 ret = aio_read_evt(ctx, &ent);
1111 if (unlikely(ret <= 0))
1112 break;
1113
1114 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1115 ent.data, ent.obj, ent.res, ent.res2);
1116
1117 /* Could we split the check in two? */
1118 ret = -EFAULT;
1119 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1120 dprintk("aio: lost an event due to EFAULT.\n");
1121 break;
1122 }
1123 ret = 0;
1124
1125 /* Good, event copied to userland, update counts. */
1126 event ++;
1127 i ++;
1128 }
1129
1130 if (min_nr <= i)
1131 return i;
1132 if (ret)
1133 return ret;
1134
1135 /* End fast path */
1136
1137 /* racey check, but it gets redone */
1138 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1139 retry = 1;
1140 aio_run_all_iocbs(ctx);
1141 goto retry;
1142 }
1143
1144 init_timeout(&to);
1145 if (timeout) {
1146 struct timespec ts;
1147 ret = -EFAULT;
1148 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1149 goto out;
1150
1151 set_timeout(start_jiffies, &to, &ts);
1152 }
1153
1154 while (likely(i < nr)) {
1155 add_wait_queue_exclusive(&ctx->wait, &wait);
1156 do {
1157 set_task_state(tsk, TASK_INTERRUPTIBLE);
1158 ret = aio_read_evt(ctx, &ent);
1159 if (ret)
1160 break;
1161 if (min_nr <= i)
1162 break;
1163 ret = 0;
1164 if (to.timed_out) /* Only check after read evt */
1165 break;
1166 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 if (signal_pending(tsk)) {
1168 ret = -EINTR;
1169 break;
1170 }
1171 /*ret = aio_read_evt(ctx, &ent);*/
1172 } while (1) ;
1173
1174 set_task_state(tsk, TASK_RUNNING);
1175 remove_wait_queue(&ctx->wait, &wait);
1176
1177 if (unlikely(ret <= 0))
1178 break;
1179
1180 ret = -EFAULT;
1181 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1182 dprintk("aio: lost an event due to EFAULT.\n");
1183 break;
1184 }
1185
1186 /* Good, event copied to userland, update counts. */
1187 event ++;
1188 i ++;
1189 }
1190
1191 if (timeout)
1192 clear_timeout(&to);
1193out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 return i ? i : ret;
1195}
1196
1197/* Take an ioctx and remove it from the list of ioctx's. Protects
1198 * against races with itself via ->dead.
1199 */
1200static void io_destroy(struct kioctx *ioctx)
1201{
1202 struct mm_struct *mm = current->mm;
1203 struct kioctx **tmp;
1204 int was_dead;
1205
1206 /* delete the entry from the list is someone else hasn't already */
1207 write_lock(&mm->ioctx_list_lock);
1208 was_dead = ioctx->dead;
1209 ioctx->dead = 1;
1210 for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx;
1211 tmp = &(*tmp)->next)
1212 ;
1213 if (*tmp)
1214 *tmp = ioctx->next;
1215 write_unlock(&mm->ioctx_list_lock);
1216
1217 dprintk("aio_release(%p)\n", ioctx);
1218 if (likely(!was_dead))
1219 put_ioctx(ioctx); /* twice for the list */
1220
1221 aio_cancel_all(ioctx);
1222 wait_for_all_aios(ioctx);
1223 put_ioctx(ioctx); /* once for the lookup */
1224}
1225
1226/* sys_io_setup:
1227 * Create an aio_context capable of receiving at least nr_events.
1228 * ctxp must not point to an aio_context that already exists, and
1229 * must be initialized to 0 prior to the call. On successful
1230 * creation of the aio_context, *ctxp is filled in with the resulting
1231 * handle. May fail with -EINVAL if *ctxp is not initialized,
1232 * if the specified nr_events exceeds internal limits. May fail
1233 * with -EAGAIN if the specified nr_events exceeds the user's limit
1234 * of available events. May fail with -ENOMEM if insufficient kernel
1235 * resources are available. May fail with -EFAULT if an invalid
1236 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1237 * implemented.
1238 */
1239asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)
1240{
1241 struct kioctx *ioctx = NULL;
1242 unsigned long ctx;
1243 long ret;
1244
1245 ret = get_user(ctx, ctxp);
1246 if (unlikely(ret))
1247 goto out;
1248
1249 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001250 if (unlikely(ctx || nr_events == 0)) {
1251 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1252 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 goto out;
1254 }
1255
1256 ioctx = ioctx_alloc(nr_events);
1257 ret = PTR_ERR(ioctx);
1258 if (!IS_ERR(ioctx)) {
1259 ret = put_user(ioctx->user_id, ctxp);
1260 if (!ret)
1261 return 0;
1262
1263 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1264 io_destroy(ioctx);
1265 }
1266
1267out:
1268 return ret;
1269}
1270
1271/* sys_io_destroy:
1272 * Destroy the aio_context specified. May cancel any outstanding
1273 * AIOs and block on completion. Will fail with -ENOSYS if not
1274 * implemented. May fail with -EFAULT if the context pointed to
1275 * is invalid.
1276 */
1277asmlinkage long sys_io_destroy(aio_context_t ctx)
1278{
1279 struct kioctx *ioctx = lookup_ioctx(ctx);
1280 if (likely(NULL != ioctx)) {
1281 io_destroy(ioctx);
1282 return 0;
1283 }
1284 pr_debug("EINVAL: io_destroy: invalid context id\n");
1285 return -EINVAL;
1286}
1287
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001288static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1289{
1290 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1291
1292 BUG_ON(ret <= 0);
1293
1294 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1295 ssize_t this = min((ssize_t)iov->iov_len, ret);
1296 iov->iov_base += this;
1297 iov->iov_len -= this;
1298 iocb->ki_left -= this;
1299 ret -= this;
1300 if (iov->iov_len == 0) {
1301 iocb->ki_cur_seg++;
1302 iov++;
1303 }
1304 }
1305
1306 /* the caller should not have done more io than what fit in
1307 * the remaining iovecs */
1308 BUG_ON(ret > 0 && iocb->ki_left == 0);
1309}
1310
1311static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312{
1313 struct file *file = iocb->ki_filp;
1314 struct address_space *mapping = file->f_mapping;
1315 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001316 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1317 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001319 unsigned short opcode;
1320
1321 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1322 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1323 rw_op = file->f_op->aio_read;
1324 opcode = IOCB_CMD_PREADV;
1325 } else {
1326 rw_op = file->f_op->aio_write;
1327 opcode = IOCB_CMD_PWRITEV;
1328 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329
Zach Brown897f15f2005-09-30 11:58:55 -07001330 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001331 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1332 iocb->ki_nr_segs - iocb->ki_cur_seg,
1333 iocb->ki_pos);
1334 if (ret > 0)
1335 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001336
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001337 /* retry all partial writes. retry partial reads as long as its a
1338 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001339 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001340 (opcode == IOCB_CMD_PWRITEV ||
1341 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342
1343 /* This means we must have transferred all that we could */
1344 /* No need to retry anymore */
1345 if ((ret == 0) || (iocb->ki_left == 0))
1346 ret = iocb->ki_nbytes - iocb->ki_left;
1347
1348 return ret;
1349}
1350
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351static ssize_t aio_fdsync(struct kiocb *iocb)
1352{
1353 struct file *file = iocb->ki_filp;
1354 ssize_t ret = -EINVAL;
1355
1356 if (file->f_op->aio_fsync)
1357 ret = file->f_op->aio_fsync(iocb, 1);
1358 return ret;
1359}
1360
1361static ssize_t aio_fsync(struct kiocb *iocb)
1362{
1363 struct file *file = iocb->ki_filp;
1364 ssize_t ret = -EINVAL;
1365
1366 if (file->f_op->aio_fsync)
1367 ret = file->f_op->aio_fsync(iocb, 0);
1368 return ret;
1369}
1370
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001371static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
1372{
1373 ssize_t ret;
1374
1375 ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
1376 kiocb->ki_nbytes, 1,
1377 &kiocb->ki_inline_vec, &kiocb->ki_iovec);
1378 if (ret < 0)
1379 goto out;
1380
1381 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1382 kiocb->ki_cur_seg = 0;
1383 /* ki_nbytes/left now reflect bytes instead of segs */
1384 kiocb->ki_nbytes = ret;
1385 kiocb->ki_left = ret;
1386
1387 ret = 0;
1388out:
1389 return ret;
1390}
1391
1392static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1393{
1394 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1395 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1396 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1397 kiocb->ki_nr_segs = 1;
1398 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001399 return 0;
1400}
1401
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402/*
1403 * aio_setup_iocb:
1404 * Performs the initial checks and aio retry method
1405 * setup for the kiocb at the time of io submission.
1406 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001407static ssize_t aio_setup_iocb(struct kiocb *kiocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408{
1409 struct file *file = kiocb->ki_filp;
1410 ssize_t ret = 0;
1411
1412 switch (kiocb->ki_opcode) {
1413 case IOCB_CMD_PREAD:
1414 ret = -EBADF;
1415 if (unlikely(!(file->f_mode & FMODE_READ)))
1416 break;
1417 ret = -EFAULT;
1418 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1419 kiocb->ki_left)))
1420 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001421 ret = security_file_permission(file, MAY_READ);
1422 if (unlikely(ret))
1423 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001424 ret = aio_setup_single_vector(kiocb);
1425 if (ret)
1426 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 ret = -EINVAL;
1428 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001429 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 break;
1431 case IOCB_CMD_PWRITE:
1432 ret = -EBADF;
1433 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1434 break;
1435 ret = -EFAULT;
1436 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1437 kiocb->ki_left)))
1438 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001439 ret = security_file_permission(file, MAY_WRITE);
1440 if (unlikely(ret))
1441 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001442 ret = aio_setup_single_vector(kiocb);
1443 if (ret)
1444 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445 ret = -EINVAL;
1446 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001447 kiocb->ki_retry = aio_rw_vect_retry;
1448 break;
1449 case IOCB_CMD_PREADV:
1450 ret = -EBADF;
1451 if (unlikely(!(file->f_mode & FMODE_READ)))
1452 break;
1453 ret = security_file_permission(file, MAY_READ);
1454 if (unlikely(ret))
1455 break;
1456 ret = aio_setup_vectored_rw(READ, kiocb);
1457 if (ret)
1458 break;
1459 ret = -EINVAL;
1460 if (file->f_op->aio_read)
1461 kiocb->ki_retry = aio_rw_vect_retry;
1462 break;
1463 case IOCB_CMD_PWRITEV:
1464 ret = -EBADF;
1465 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1466 break;
1467 ret = security_file_permission(file, MAY_WRITE);
1468 if (unlikely(ret))
1469 break;
1470 ret = aio_setup_vectored_rw(WRITE, kiocb);
1471 if (ret)
1472 break;
1473 ret = -EINVAL;
1474 if (file->f_op->aio_write)
1475 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 break;
1477 case IOCB_CMD_FDSYNC:
1478 ret = -EINVAL;
1479 if (file->f_op->aio_fsync)
1480 kiocb->ki_retry = aio_fdsync;
1481 break;
1482 case IOCB_CMD_FSYNC:
1483 ret = -EINVAL;
1484 if (file->f_op->aio_fsync)
1485 kiocb->ki_retry = aio_fsync;
1486 break;
1487 default:
1488 dprintk("EINVAL: io_submit: no operation provided\n");
1489 ret = -EINVAL;
1490 }
1491
1492 if (!kiocb->ki_retry)
1493 return ret;
1494
1495 return 0;
1496}
1497
1498/*
1499 * aio_wake_function:
1500 * wait queue callback function for aio notification,
1501 * Simply triggers a retry of the operation via kick_iocb.
1502 *
1503 * This callback is specified in the wait queue entry in
1504 * a kiocb (current->io_wait points to this wait queue
1505 * entry when an aio operation executes; it is used
1506 * instead of a synchronous wait when an i/o blocking
1507 * condition is encountered during aio).
1508 *
1509 * Note:
1510 * This routine is executed with the wait queue lock held.
1511 * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
1512 * the ioctx lock inside the wait queue lock. This is safe
1513 * because this callback isn't used for wait queues which
1514 * are nested inside ioctx lock (i.e. ctx->wait)
1515 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001516static int aio_wake_function(wait_queue_t *wait, unsigned mode,
1517 int sync, void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518{
1519 struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
1520
1521 list_del_init(&wait->task_list);
1522 kick_iocb(iocb);
1523 return 1;
1524}
1525
1526int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1527 struct iocb *iocb)
1528{
1529 struct kiocb *req;
1530 struct file *file;
1531 ssize_t ret;
1532
1533 /* enforce forwards compatibility on users */
1534 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2 ||
1535 iocb->aio_reserved3)) {
1536 pr_debug("EINVAL: io_submit: reserve field set\n");
1537 return -EINVAL;
1538 }
1539
1540 /* prevent overflows */
1541 if (unlikely(
1542 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1543 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1544 ((ssize_t)iocb->aio_nbytes < 0)
1545 )) {
1546 pr_debug("EINVAL: io_submit: overflow check\n");
1547 return -EINVAL;
1548 }
1549
1550 file = fget(iocb->aio_fildes);
1551 if (unlikely(!file))
1552 return -EBADF;
1553
1554 req = aio_get_req(ctx); /* returns with 2 references to req */
1555 if (unlikely(!req)) {
1556 fput(file);
1557 return -EAGAIN;
1558 }
1559
1560 req->ki_filp = file;
Ken Chen212079c2005-05-01 08:59:15 -07001561 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 if (unlikely(ret)) {
1563 dprintk("EFAULT: aio_key\n");
1564 goto out_put_req;
1565 }
1566
1567 req->ki_obj.user = user_iocb;
1568 req->ki_user_data = iocb->aio_data;
1569 req->ki_pos = iocb->aio_offset;
1570
1571 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1572 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1573 req->ki_opcode = iocb->aio_lio_opcode;
1574 init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
1575 INIT_LIST_HEAD(&req->ki_wait.task_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576
1577 ret = aio_setup_iocb(req);
1578
1579 if (ret)
1580 goto out_put_req;
1581
1582 spin_lock_irq(&ctx->ctx_lock);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001583 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001584 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001585 /* drain the run list */
1586 while (__aio_run_iocbs(ctx))
1587 ;
1588 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 spin_unlock_irq(&ctx->ctx_lock);
1590 aio_put_req(req); /* drop extra ref to req */
1591 return 0;
1592
1593out_put_req:
1594 aio_put_req(req); /* drop extra ref to req */
1595 aio_put_req(req); /* drop i/o ref to req */
1596 return ret;
1597}
1598
1599/* sys_io_submit:
1600 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1601 * the number of iocbs queued. May return -EINVAL if the aio_context
1602 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1603 * *iocbpp[0] is not properly initialized, if the operation specified
1604 * is invalid for the file descriptor in the iocb. May fail with
1605 * -EFAULT if any of the data structures point to invalid data. May
1606 * fail with -EBADF if the file descriptor specified in the first
1607 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1608 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1609 * fail with -ENOSYS if not implemented.
1610 */
1611asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
1612 struct iocb __user * __user *iocbpp)
1613{
1614 struct kioctx *ctx;
1615 long ret = 0;
1616 int i;
1617
1618 if (unlikely(nr < 0))
1619 return -EINVAL;
1620
1621 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1622 return -EFAULT;
1623
1624 ctx = lookup_ioctx(ctx_id);
1625 if (unlikely(!ctx)) {
1626 pr_debug("EINVAL: io_submit: invalid context id\n");
1627 return -EINVAL;
1628 }
1629
1630 /*
1631 * AKPM: should this return a partial result if some of the IOs were
1632 * successfully submitted?
1633 */
1634 for (i=0; i<nr; i++) {
1635 struct iocb __user *user_iocb;
1636 struct iocb tmp;
1637
1638 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1639 ret = -EFAULT;
1640 break;
1641 }
1642
1643 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1644 ret = -EFAULT;
1645 break;
1646 }
1647
1648 ret = io_submit_one(ctx, user_iocb, &tmp);
1649 if (ret)
1650 break;
1651 }
1652
1653 put_ioctx(ctx);
1654 return i ? i : ret;
1655}
1656
1657/* lookup_kiocb
1658 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001660static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1661 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662{
1663 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001664
1665 assert_spin_locked(&ctx->ctx_lock);
1666
Linus Torvalds1da177e2005-04-16 15:20:36 -07001667 /* TODO: use a hash or array, this sucks. */
1668 list_for_each(pos, &ctx->active_reqs) {
1669 struct kiocb *kiocb = list_kiocb(pos);
1670 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1671 return kiocb;
1672 }
1673 return NULL;
1674}
1675
1676/* sys_io_cancel:
1677 * Attempts to cancel an iocb previously passed to io_submit. If
1678 * the operation is successfully cancelled, the resulting event is
1679 * copied into the memory pointed to by result without being placed
1680 * into the completion queue and 0 is returned. May fail with
1681 * -EFAULT if any of the data structures pointed to are invalid.
1682 * May fail with -EINVAL if aio_context specified by ctx_id is
1683 * invalid. May fail with -EAGAIN if the iocb specified was not
1684 * cancelled. Will fail with -ENOSYS if not implemented.
1685 */
1686asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
1687 struct io_event __user *result)
1688{
1689 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1690 struct kioctx *ctx;
1691 struct kiocb *kiocb;
1692 u32 key;
1693 int ret;
1694
1695 ret = get_user(key, &iocb->aio_key);
1696 if (unlikely(ret))
1697 return -EFAULT;
1698
1699 ctx = lookup_ioctx(ctx_id);
1700 if (unlikely(!ctx))
1701 return -EINVAL;
1702
1703 spin_lock_irq(&ctx->ctx_lock);
1704 ret = -EAGAIN;
1705 kiocb = lookup_kiocb(ctx, iocb, key);
1706 if (kiocb && kiocb->ki_cancel) {
1707 cancel = kiocb->ki_cancel;
1708 kiocb->ki_users ++;
1709 kiocbSetCancelled(kiocb);
1710 } else
1711 cancel = NULL;
1712 spin_unlock_irq(&ctx->ctx_lock);
1713
1714 if (NULL != cancel) {
1715 struct io_event tmp;
1716 pr_debug("calling cancel\n");
1717 memset(&tmp, 0, sizeof(tmp));
1718 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1719 tmp.data = kiocb->ki_user_data;
1720 ret = cancel(kiocb, &tmp);
1721 if (!ret) {
1722 /* Cancellation succeeded -- copy the result
1723 * into the user's buffer.
1724 */
1725 if (copy_to_user(result, &tmp, sizeof(tmp)))
1726 ret = -EFAULT;
1727 }
1728 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001729 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
1731 put_ioctx(ctx);
1732
1733 return ret;
1734}
1735
1736/* io_getevents:
1737 * Attempts to read at least min_nr events and up to nr events from
1738 * the completion queue for the aio_context specified by ctx_id. May
1739 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1740 * if nr is out of range, if when is out of range. May fail with
1741 * -EFAULT if any of the memory specified to is invalid. May return
1742 * 0 or < min_nr if no events are available and the timeout specified
1743 * by when has elapsed, where when == NULL specifies an infinite
1744 * timeout. Note that the timeout pointed to by when is relative and
1745 * will be updated if not NULL and the operation blocks. Will fail
1746 * with -ENOSYS if not implemented.
1747 */
1748asmlinkage long sys_io_getevents(aio_context_t ctx_id,
1749 long min_nr,
1750 long nr,
1751 struct io_event __user *events,
1752 struct timespec __user *timeout)
1753{
1754 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1755 long ret = -EINVAL;
1756
1757 if (likely(ioctx)) {
1758 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1759 ret = read_events(ioctx, min_nr, nr, events, timeout);
1760 put_ioctx(ioctx);
1761 }
1762
1763 return ret;
1764}
1765
1766__initcall(aio_setup);
1767
1768EXPORT_SYMBOL(aio_complete);
1769EXPORT_SYMBOL(aio_put_req);
1770EXPORT_SYMBOL(wait_on_sync_kiocb);