2 * An async IO implementation for Linux
3 * Written by Benjamin LaHaise <bcrl@kvack.org>
5 * Implements an efficient asynchronous io interface.
7 * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
9 * See ../COPYING for licensing terms.
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>
21 #include <linux/sched.h>
23 #include <linux/file.h>
25 #include <linux/mman.h>
26 #include <linux/slab.h>
27 #include <linux/timer.h>
28 #include <linux/aio.h>
29 #include <linux/highmem.h>
30 #include <linux/workqueue.h>
31 #include <linux/security.h>
32 #include <linux/rcuref.h>
34 #include <asm/kmap_types.h>
35 #include <asm/uaccess.h>
36 #include <asm/mmu_context.h>
39 #define dprintk printk
41 #define dprintk(x...) do { ; } while (0)
44 /*------ sysctl variables----*/
45 static DEFINE_SPINLOCK(aio_nr_lock
);
46 unsigned long aio_nr
; /* current system wide number of aio requests */
47 unsigned long aio_max_nr
= 0x10000; /* system wide maximum number of aio requests */
48 /*----end sysctl variables---*/
50 static kmem_cache_t
*kiocb_cachep
;
51 static kmem_cache_t
*kioctx_cachep
;
53 static struct workqueue_struct
*aio_wq
;
55 /* Used for rare fput completion. */
56 static void aio_fput_routine(void *);
57 static DECLARE_WORK(fput_work
, aio_fput_routine
, NULL
);
59 static DEFINE_SPINLOCK(fput_lock
);
60 static LIST_HEAD(fput_head
);
62 static void aio_kick_handler(void *);
63 static void aio_queue_work(struct kioctx
*);
66 * Creates the slab caches used by the aio routines, panic on
67 * failure as this is done early during the boot sequence.
69 static int __init
aio_setup(void)
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
);
76 aio_wq
= create_workqueue("aio");
78 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page
));
83 static void aio_free_ring(struct kioctx
*ctx
)
85 struct aio_ring_info
*info
= &ctx
->ring_info
;
88 for (i
=0; i
<info
->nr_pages
; i
++)
89 put_page(info
->ring_pages
[i
]);
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
);
97 if (info
->ring_pages
&& info
->ring_pages
!= info
->internal_pages
)
98 kfree(info
->ring_pages
);
99 info
->ring_pages
= NULL
;
103 static int aio_setup_ring(struct kioctx
*ctx
)
105 struct aio_ring
*ring
;
106 struct aio_ring_info
*info
= &ctx
->ring_info
;
107 unsigned nr_events
= ctx
->max_reqs
;
111 /* Compensate for the ring buffer's head/tail overlap entry */
112 nr_events
+= 2; /* 1 is required, 2 for good luck */
114 size
= sizeof(struct aio_ring
);
115 size
+= sizeof(struct io_event
) * nr_events
;
116 nr_pages
= (size
+ PAGE_SIZE
-1) >> PAGE_SHIFT
;
121 nr_events
= (PAGE_SIZE
* nr_pages
- sizeof(struct aio_ring
)) / sizeof(struct io_event
);
124 info
->ring_pages
= info
->internal_pages
;
125 if (nr_pages
> AIO_RING_PAGES
) {
126 info
->ring_pages
= kmalloc(sizeof(struct page
*) * nr_pages
, GFP_KERNEL
);
127 if (!info
->ring_pages
)
129 memset(info
->ring_pages
, 0, sizeof(struct page
*) * nr_pages
);
132 info
->mmap_size
= nr_pages
* PAGE_SIZE
;
133 dprintk("attempting mmap of %lu bytes\n", info
->mmap_size
);
134 down_write(&ctx
->mm
->mmap_sem
);
135 info
->mmap_base
= do_mmap(NULL
, 0, info
->mmap_size
,
136 PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_PRIVATE
,
138 if (IS_ERR((void *)info
->mmap_base
)) {
139 up_write(&ctx
->mm
->mmap_sem
);
140 printk("mmap err: %ld\n", -info
->mmap_base
);
146 dprintk("mmap address: 0x%08lx\n", info
->mmap_base
);
147 info
->nr_pages
= get_user_pages(current
, ctx
->mm
,
148 info
->mmap_base
, nr_pages
,
149 1, 0, info
->ring_pages
, NULL
);
150 up_write(&ctx
->mm
->mmap_sem
);
152 if (unlikely(info
->nr_pages
!= nr_pages
)) {
157 ctx
->user_id
= info
->mmap_base
;
159 info
->nr
= nr_events
; /* trusted copy */
161 ring
= kmap_atomic(info
->ring_pages
[0], KM_USER0
);
162 ring
->nr
= nr_events
; /* user copy */
163 ring
->id
= ctx
->user_id
;
164 ring
->head
= ring
->tail
= 0;
165 ring
->magic
= AIO_RING_MAGIC
;
166 ring
->compat_features
= AIO_RING_COMPAT_FEATURES
;
167 ring
->incompat_features
= AIO_RING_INCOMPAT_FEATURES
;
168 ring
->header_length
= sizeof(struct aio_ring
);
169 kunmap_atomic(ring
, KM_USER0
);
175 /* aio_ring_event: returns a pointer to the event at the given index from
176 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
178 #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
179 #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
180 #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
182 #define aio_ring_event(info, nr, km) ({ \
183 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
184 struct io_event *__event; \
185 __event = kmap_atomic( \
186 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
187 __event += pos % AIO_EVENTS_PER_PAGE; \
191 #define put_aio_ring_event(event, km) do { \
192 struct io_event *__event = (event); \
194 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
198 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
200 static struct kioctx
*ioctx_alloc(unsigned nr_events
)
202 struct mm_struct
*mm
;
205 /* Prevent overflows */
206 if ((nr_events
> (0x10000000U
/ sizeof(struct io_event
))) ||
207 (nr_events
> (0x10000000U
/ sizeof(struct kiocb
)))) {
208 pr_debug("ENOMEM: nr_events too high\n");
209 return ERR_PTR(-EINVAL
);
212 if ((unsigned long)nr_events
> aio_max_nr
)
213 return ERR_PTR(-EAGAIN
);
215 ctx
= kmem_cache_alloc(kioctx_cachep
, GFP_KERNEL
);
217 return ERR_PTR(-ENOMEM
);
219 memset(ctx
, 0, sizeof(*ctx
));
220 ctx
->max_reqs
= nr_events
;
221 mm
= ctx
->mm
= current
->mm
;
222 atomic_inc(&mm
->mm_count
);
224 atomic_set(&ctx
->users
, 1);
225 spin_lock_init(&ctx
->ctx_lock
);
226 spin_lock_init(&ctx
->ring_info
.ring_lock
);
227 init_waitqueue_head(&ctx
->wait
);
229 INIT_LIST_HEAD(&ctx
->active_reqs
);
230 INIT_LIST_HEAD(&ctx
->run_list
);
231 INIT_WORK(&ctx
->wq
, aio_kick_handler
, ctx
);
233 if (aio_setup_ring(ctx
) < 0)
236 /* limit the number of system wide aios */
237 spin_lock(&aio_nr_lock
);
238 if (aio_nr
+ ctx
->max_reqs
> aio_max_nr
||
239 aio_nr
+ ctx
->max_reqs
< aio_nr
)
242 aio_nr
+= ctx
->max_reqs
;
243 spin_unlock(&aio_nr_lock
);
244 if (ctx
->max_reqs
== 0)
247 /* now link into global list. kludge. FIXME */
248 write_lock(&mm
->ioctx_list_lock
);
249 ctx
->next
= mm
->ioctx_list
;
250 mm
->ioctx_list
= ctx
;
251 write_unlock(&mm
->ioctx_list_lock
);
253 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
254 ctx
, ctx
->user_id
, current
->mm
, ctx
->ring_info
.nr
);
259 return ERR_PTR(-EAGAIN
);
263 kmem_cache_free(kioctx_cachep
, ctx
);
264 ctx
= ERR_PTR(-ENOMEM
);
266 dprintk("aio: error allocating ioctx %p\n", ctx
);
271 * Cancels all outstanding aio requests on an aio context. Used
272 * when the processes owning a context have all exited to encourage
273 * the rapid destruction of the kioctx.
275 static void aio_cancel_all(struct kioctx
*ctx
)
277 int (*cancel
)(struct kiocb
*, struct io_event
*);
279 spin_lock_irq(&ctx
->ctx_lock
);
281 while (!list_empty(&ctx
->active_reqs
)) {
282 struct list_head
*pos
= ctx
->active_reqs
.next
;
283 struct kiocb
*iocb
= list_kiocb(pos
);
284 list_del_init(&iocb
->ki_list
);
285 cancel
= iocb
->ki_cancel
;
286 kiocbSetCancelled(iocb
);
289 spin_unlock_irq(&ctx
->ctx_lock
);
291 spin_lock_irq(&ctx
->ctx_lock
);
294 spin_unlock_irq(&ctx
->ctx_lock
);
297 static void wait_for_all_aios(struct kioctx
*ctx
)
299 struct task_struct
*tsk
= current
;
300 DECLARE_WAITQUEUE(wait
, tsk
);
302 if (!ctx
->reqs_active
)
305 add_wait_queue(&ctx
->wait
, &wait
);
306 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
307 while (ctx
->reqs_active
) {
309 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
311 __set_task_state(tsk
, TASK_RUNNING
);
312 remove_wait_queue(&ctx
->wait
, &wait
);
315 /* wait_on_sync_kiocb:
316 * Waits on the given sync kiocb to complete.
318 ssize_t fastcall
wait_on_sync_kiocb(struct kiocb
*iocb
)
320 while (iocb
->ki_users
) {
321 set_current_state(TASK_UNINTERRUPTIBLE
);
326 __set_current_state(TASK_RUNNING
);
327 return iocb
->ki_user_data
;
330 /* exit_aio: called when the last user of mm goes away. At this point,
331 * there is no way for any new requests to be submited or any of the
332 * io_* syscalls to be called on the context. However, there may be
333 * outstanding requests which hold references to the context; as they
334 * go away, they will call put_ioctx and release any pinned memory
335 * associated with the request (held via struct page * references).
337 void fastcall
exit_aio(struct mm_struct
*mm
)
339 struct kioctx
*ctx
= mm
->ioctx_list
;
340 mm
->ioctx_list
= NULL
;
342 struct kioctx
*next
= ctx
->next
;
346 wait_for_all_aios(ctx
);
348 * this is an overkill, but ensures we don't leave
349 * the ctx on the aio_wq
351 flush_workqueue(aio_wq
);
353 if (1 != atomic_read(&ctx
->users
))
355 "exit_aio:ioctx still alive: %d %d %d\n",
356 atomic_read(&ctx
->users
), ctx
->dead
,
364 * Called when the last user of an aio context has gone away,
365 * and the struct needs to be freed.
367 void fastcall
__put_ioctx(struct kioctx
*ctx
)
369 unsigned nr_events
= ctx
->max_reqs
;
371 if (unlikely(ctx
->reqs_active
))
374 cancel_delayed_work(&ctx
->wq
);
375 flush_workqueue(aio_wq
);
379 pr_debug("__put_ioctx: freeing %p\n", ctx
);
380 kmem_cache_free(kioctx_cachep
, ctx
);
383 spin_lock(&aio_nr_lock
);
384 BUG_ON(aio_nr
- nr_events
> aio_nr
);
386 spin_unlock(&aio_nr_lock
);
391 * Allocate a slot for an aio request. Increments the users count
392 * of the kioctx so that the kioctx stays around until all requests are
393 * complete. Returns NULL if no requests are free.
395 * Returns with kiocb->users set to 2. The io submit code path holds
396 * an extra reference while submitting the i/o.
397 * This prevents races between the aio code path referencing the
398 * req (after submitting it) and aio_complete() freeing the req.
400 static struct kiocb
*FASTCALL(__aio_get_req(struct kioctx
*ctx
));
401 static struct kiocb fastcall
*__aio_get_req(struct kioctx
*ctx
)
403 struct kiocb
*req
= NULL
;
404 struct aio_ring
*ring
;
407 req
= kmem_cache_alloc(kiocb_cachep
, GFP_KERNEL
);
415 req
->ki_cancel
= NULL
;
416 req
->ki_retry
= NULL
;
419 INIT_LIST_HEAD(&req
->ki_run_list
);
421 /* Check if the completion queue has enough free space to
422 * accept an event from this io.
424 spin_lock_irq(&ctx
->ctx_lock
);
425 ring
= kmap_atomic(ctx
->ring_info
.ring_pages
[0], KM_USER0
);
426 if (ctx
->reqs_active
< aio_ring_avail(&ctx
->ring_info
, ring
)) {
427 list_add(&req
->ki_list
, &ctx
->active_reqs
);
432 kunmap_atomic(ring
, KM_USER0
);
433 spin_unlock_irq(&ctx
->ctx_lock
);
436 kmem_cache_free(kiocb_cachep
, req
);
443 static inline struct kiocb
*aio_get_req(struct kioctx
*ctx
)
446 /* Handle a potential starvation case -- should be exceedingly rare as
447 * requests will be stuck on fput_head only if the aio_fput_routine is
448 * delayed and the requests were the last user of the struct file.
450 req
= __aio_get_req(ctx
);
451 if (unlikely(NULL
== req
)) {
452 aio_fput_routine(NULL
);
453 req
= __aio_get_req(ctx
);
458 static inline void really_put_req(struct kioctx
*ctx
, struct kiocb
*req
)
462 kmem_cache_free(kiocb_cachep
, req
);
465 if (unlikely(!ctx
->reqs_active
&& ctx
->dead
))
469 static void aio_fput_routine(void *data
)
471 spin_lock_irq(&fput_lock
);
472 while (likely(!list_empty(&fput_head
))) {
473 struct kiocb
*req
= list_kiocb(fput_head
.next
);
474 struct kioctx
*ctx
= req
->ki_ctx
;
476 list_del(&req
->ki_list
);
477 spin_unlock_irq(&fput_lock
);
479 /* Complete the fput */
480 __fput(req
->ki_filp
);
482 /* Link the iocb into the context's free list */
483 spin_lock_irq(&ctx
->ctx_lock
);
484 really_put_req(ctx
, req
);
485 spin_unlock_irq(&ctx
->ctx_lock
);
488 spin_lock_irq(&fput_lock
);
490 spin_unlock_irq(&fput_lock
);
494 * Returns true if this put was the last user of the request.
496 static int __aio_put_req(struct kioctx
*ctx
, struct kiocb
*req
)
498 dprintk(KERN_DEBUG
"aio_put(%p): f_count=%d\n",
499 req
, atomic_read(&req
->ki_filp
->f_count
));
502 if (unlikely(req
->ki_users
< 0))
504 if (likely(req
->ki_users
))
506 list_del(&req
->ki_list
); /* remove from active_reqs */
507 req
->ki_cancel
= NULL
;
508 req
->ki_retry
= NULL
;
510 /* Must be done under the lock to serialise against cancellation.
511 * Call this aio_fput as it duplicates fput via the fput_work.
513 if (unlikely(rcuref_dec_and_test(&req
->ki_filp
->f_count
))) {
515 spin_lock(&fput_lock
);
516 list_add(&req
->ki_list
, &fput_head
);
517 spin_unlock(&fput_lock
);
518 queue_work(aio_wq
, &fput_work
);
520 really_put_req(ctx
, req
);
525 * Returns true if this put was the last user of the kiocb,
526 * false if the request is still in use.
528 int fastcall
aio_put_req(struct kiocb
*req
)
530 struct kioctx
*ctx
= req
->ki_ctx
;
532 spin_lock_irq(&ctx
->ctx_lock
);
533 ret
= __aio_put_req(ctx
, req
);
534 spin_unlock_irq(&ctx
->ctx_lock
);
540 /* Lookup an ioctx id. ioctx_list is lockless for reads.
541 * FIXME: this is O(n) and is only suitable for development.
543 struct kioctx
*lookup_ioctx(unsigned long ctx_id
)
545 struct kioctx
*ioctx
;
546 struct mm_struct
*mm
;
549 read_lock(&mm
->ioctx_list_lock
);
550 for (ioctx
= mm
->ioctx_list
; ioctx
; ioctx
= ioctx
->next
)
551 if (likely(ioctx
->user_id
== ctx_id
&& !ioctx
->dead
)) {
555 read_unlock(&mm
->ioctx_list_lock
);
562 * Makes the calling kernel thread take on the specified
564 * Called by the retry thread execute retries within the
565 * iocb issuer's mm context, so that copy_from/to_user
566 * operations work seamlessly for aio.
567 * (Note: this routine is intended to be called only
568 * from a kernel thread context)
570 static void use_mm(struct mm_struct
*mm
)
572 struct mm_struct
*active_mm
;
573 struct task_struct
*tsk
= current
;
576 tsk
->flags
|= PF_BORROWED_MM
;
577 active_mm
= tsk
->active_mm
;
578 atomic_inc(&mm
->mm_count
);
582 * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
583 * it won't work. Update it accordingly if you change it here
585 activate_mm(active_mm
, mm
);
593 * Reverses the effect of use_mm, i.e. releases the
594 * specified mm context which was earlier taken on
595 * by the calling kernel thread
596 * (Note: this routine is intended to be called only
597 * from a kernel thread context)
599 * Comments: Called with ctx->ctx_lock held. This nests
600 * task_lock instead ctx_lock.
602 static void unuse_mm(struct mm_struct
*mm
)
604 struct task_struct
*tsk
= current
;
607 tsk
->flags
&= ~PF_BORROWED_MM
;
609 /* active_mm is still 'mm' */
610 enter_lazy_tlb(mm
, tsk
);
615 * Queue up a kiocb to be retried. Assumes that the kiocb
616 * has already been marked as kicked, and places it on
617 * the retry run list for the corresponding ioctx, if it
618 * isn't already queued. Returns 1 if it actually queued
619 * the kiocb (to tell the caller to activate the work
620 * queue to process it), or 0, if it found that it was
623 * Should be called with the spin lock iocb->ki_ctx->ctx_lock
626 static inline int __queue_kicked_iocb(struct kiocb
*iocb
)
628 struct kioctx
*ctx
= iocb
->ki_ctx
;
630 if (list_empty(&iocb
->ki_run_list
)) {
631 list_add_tail(&iocb
->ki_run_list
,
639 * This is the core aio execution routine. It is
640 * invoked both for initial i/o submission and
641 * subsequent retries via the aio_kick_handler.
642 * Expects to be invoked with iocb->ki_ctx->lock
643 * already held. The lock is released and reaquired
644 * as needed during processing.
646 * Calls the iocb retry method (already setup for the
647 * iocb on initial submission) for operation specific
648 * handling, but takes care of most of common retry
649 * execution details for a given iocb. The retry method
650 * needs to be non-blocking as far as possible, to avoid
651 * holding up other iocbs waiting to be serviced by the
652 * retry kernel thread.
654 * The trickier parts in this code have to do with
655 * ensuring that only one retry instance is in progress
656 * for a given iocb at any time. Providing that guarantee
657 * simplifies the coding of individual aio operations as
658 * it avoids various potential races.
660 static ssize_t
aio_run_iocb(struct kiocb
*iocb
)
662 struct kioctx
*ctx
= iocb
->ki_ctx
;
663 ssize_t (*retry
)(struct kiocb
*);
666 if (iocb
->ki_retried
++ > 1024*1024) {
667 printk("Maximal retry count. Bytes done %Zd\n",
668 iocb
->ki_nbytes
- iocb
->ki_left
);
672 if (!(iocb
->ki_retried
& 0xff)) {
673 pr_debug("%ld retry: %d of %d\n", iocb
->ki_retried
,
674 iocb
->ki_nbytes
- iocb
->ki_left
, iocb
->ki_nbytes
);
677 if (!(retry
= iocb
->ki_retry
)) {
678 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
683 * We don't want the next retry iteration for this
684 * operation to start until this one has returned and
685 * updated the iocb state. However, wait_queue functions
686 * can trigger a kick_iocb from interrupt context in the
687 * meantime, indicating that data is available for the next
688 * iteration. We want to remember that and enable the
689 * next retry iteration _after_ we are through with
692 * So, in order to be able to register a "kick", but
693 * prevent it from being queued now, we clear the kick
694 * flag, but make the kick code *think* that the iocb is
695 * still on the run list until we are actually done.
696 * When we are done with this iteration, we check if
697 * the iocb was kicked in the meantime and if so, queue
701 kiocbClearKicked(iocb
);
704 * This is so that aio_complete knows it doesn't need to
705 * pull the iocb off the run list (We can't just call
706 * INIT_LIST_HEAD because we don't want a kick_iocb to
707 * queue this on the run list yet)
709 iocb
->ki_run_list
.next
= iocb
->ki_run_list
.prev
= NULL
;
710 spin_unlock_irq(&ctx
->ctx_lock
);
712 /* Quit retrying if the i/o has been cancelled */
713 if (kiocbIsCancelled(iocb
)) {
715 aio_complete(iocb
, ret
, 0);
716 /* must not access the iocb after this */
721 * Now we are all set to call the retry method in async
722 * context. By setting this thread's io_wait context
723 * to point to the wait queue entry inside the currently
724 * running iocb for the duration of the retry, we ensure
725 * that async notification wakeups are queued by the
726 * operation instead of blocking waits, and when notified,
727 * cause the iocb to be kicked for continuation (through
728 * the aio_wake_function callback).
730 BUG_ON(current
->io_wait
!= NULL
);
731 current
->io_wait
= &iocb
->ki_wait
;
733 current
->io_wait
= NULL
;
735 if (ret
!= -EIOCBRETRY
&& ret
!= -EIOCBQUEUED
) {
736 BUG_ON(!list_empty(&iocb
->ki_wait
.task_list
));
737 aio_complete(iocb
, ret
, 0);
740 spin_lock_irq(&ctx
->ctx_lock
);
742 if (-EIOCBRETRY
== ret
) {
744 * OK, now that we are done with this iteration
745 * and know that there is more left to go,
746 * this is where we let go so that a subsequent
747 * "kick" can start the next iteration
750 /* will make __queue_kicked_iocb succeed from here on */
751 INIT_LIST_HEAD(&iocb
->ki_run_list
);
752 /* we must queue the next iteration ourselves, if it
753 * has already been kicked */
754 if (kiocbIsKicked(iocb
)) {
755 __queue_kicked_iocb(iocb
);
758 * __queue_kicked_iocb will always return 1 here, because
759 * iocb->ki_run_list is empty at this point so it should
760 * be safe to unconditionally queue the context into the
771 * Process all pending retries queued on the ioctx
773 * Assumes it is operating within the aio issuer's mm
774 * context. Expects to be called with ctx->ctx_lock held
776 static int __aio_run_iocbs(struct kioctx
*ctx
)
781 list_splice_init(&ctx
->run_list
, &run_list
);
782 while (!list_empty(&run_list
)) {
783 iocb
= list_entry(run_list
.next
, struct kiocb
,
785 list_del(&iocb
->ki_run_list
);
787 * Hold an extra reference while retrying i/o.
789 iocb
->ki_users
++; /* grab extra reference */
791 if (__aio_put_req(ctx
, iocb
)) /* drop extra ref */
794 if (!list_empty(&ctx
->run_list
))
799 static void aio_queue_work(struct kioctx
* ctx
)
801 unsigned long timeout
;
803 * if someone is waiting, get the work started right
804 * away, otherwise, use a longer delay
807 if (waitqueue_active(&ctx
->wait
))
811 queue_delayed_work(aio_wq
, &ctx
->wq
, timeout
);
817 * Process all pending retries queued on the ioctx
819 * Assumes it is operating within the aio issuer's mm
822 static inline void aio_run_iocbs(struct kioctx
*ctx
)
826 spin_lock_irq(&ctx
->ctx_lock
);
828 requeue
= __aio_run_iocbs(ctx
);
829 spin_unlock_irq(&ctx
->ctx_lock
);
835 * just like aio_run_iocbs, but keeps running them until
836 * the list stays empty
838 static inline void aio_run_all_iocbs(struct kioctx
*ctx
)
840 spin_lock_irq(&ctx
->ctx_lock
);
841 while (__aio_run_iocbs(ctx
))
843 spin_unlock_irq(&ctx
->ctx_lock
);
848 * Work queue handler triggered to process pending
849 * retries on an ioctx. Takes on the aio issuer's
850 * mm context before running the iocbs, so that
851 * copy_xxx_user operates on the issuer's address
853 * Run on aiod's context.
855 static void aio_kick_handler(void *data
)
857 struct kioctx
*ctx
= data
;
858 mm_segment_t oldfs
= get_fs();
863 spin_lock_irq(&ctx
->ctx_lock
);
864 requeue
=__aio_run_iocbs(ctx
);
866 spin_unlock_irq(&ctx
->ctx_lock
);
869 * we're in a worker thread already, don't use queue_delayed_work,
872 queue_work(aio_wq
, &ctx
->wq
);
877 * Called by kick_iocb to queue the kiocb for retry
878 * and if required activate the aio work queue to process
881 static void try_queue_kicked_iocb(struct kiocb
*iocb
)
883 struct kioctx
*ctx
= iocb
->ki_ctx
;
887 /* We're supposed to be the only path putting the iocb back on the run
888 * list. If we find that the iocb is *back* on a wait queue already
889 * than retry has happened before we could queue the iocb. This also
890 * means that the retry could have completed and freed our iocb, no
892 BUG_ON((!list_empty(&iocb
->ki_wait
.task_list
)));
894 spin_lock_irqsave(&ctx
->ctx_lock
, flags
);
895 /* set this inside the lock so that we can't race with aio_run_iocb()
896 * testing it and putting the iocb on the run list under the lock */
897 if (!kiocbTryKick(iocb
))
898 run
= __queue_kicked_iocb(iocb
);
899 spin_unlock_irqrestore(&ctx
->ctx_lock
, flags
);
906 * Called typically from a wait queue callback context
907 * (aio_wake_function) to trigger a retry of the iocb.
908 * The retry is usually executed by aio workqueue
909 * threads (See aio_kick_handler).
911 void fastcall
kick_iocb(struct kiocb
*iocb
)
913 /* sync iocbs are easy: they can only ever be executing from a
915 if (is_sync_kiocb(iocb
)) {
916 kiocbSetKicked(iocb
);
917 wake_up_process(iocb
->ki_obj
.tsk
);
921 try_queue_kicked_iocb(iocb
);
923 EXPORT_SYMBOL(kick_iocb
);
926 * Called when the io request on the given iocb is complete.
927 * Returns true if this is the last user of the request. The
928 * only other user of the request can be the cancellation code.
930 int fastcall
aio_complete(struct kiocb
*iocb
, long res
, long res2
)
932 struct kioctx
*ctx
= iocb
->ki_ctx
;
933 struct aio_ring_info
*info
;
934 struct aio_ring
*ring
;
935 struct io_event
*event
;
940 /* Special case handling for sync iocbs: events go directly
941 * into the iocb for fast handling. Note that this will not
942 * work if we allow sync kiocbs to be cancelled. in which
943 * case the usage count checks will have to move under ctx_lock
946 if (is_sync_kiocb(iocb
)) {
949 iocb
->ki_user_data
= res
;
950 if (iocb
->ki_users
== 1) {
954 spin_lock_irq(&ctx
->ctx_lock
);
956 ret
= (0 == iocb
->ki_users
);
957 spin_unlock_irq(&ctx
->ctx_lock
);
959 /* sync iocbs put the task here for us */
960 wake_up_process(iocb
->ki_obj
.tsk
);
964 info
= &ctx
->ring_info
;
966 /* add a completion event to the ring buffer.
967 * must be done holding ctx->ctx_lock to prevent
968 * other code from messing with the tail
969 * pointer since we might be called from irq
972 spin_lock_irqsave(&ctx
->ctx_lock
, flags
);
974 if (iocb
->ki_run_list
.prev
&& !list_empty(&iocb
->ki_run_list
))
975 list_del_init(&iocb
->ki_run_list
);
978 * cancelled requests don't get events, userland was given one
979 * when the event got cancelled.
981 if (kiocbIsCancelled(iocb
))
984 ring
= kmap_atomic(info
->ring_pages
[0], KM_IRQ1
);
987 event
= aio_ring_event(info
, tail
, KM_IRQ0
);
988 if (++tail
>= info
->nr
)
991 event
->obj
= (u64
)(unsigned long)iocb
->ki_obj
.user
;
992 event
->data
= iocb
->ki_user_data
;
996 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
997 ctx
, tail
, iocb
, iocb
->ki_obj
.user
, iocb
->ki_user_data
,
1000 /* after flagging the request as done, we
1001 * must never even look at it again
1003 smp_wmb(); /* make event visible before updating tail */
1008 put_aio_ring_event(event
, KM_IRQ0
);
1009 kunmap_atomic(ring
, KM_IRQ1
);
1011 pr_debug("added to ring %p at [%lu]\n", iocb
, tail
);
1013 pr_debug("%ld retries: %d of %d\n", iocb
->ki_retried
,
1014 iocb
->ki_nbytes
- iocb
->ki_left
, iocb
->ki_nbytes
);
1016 /* everything turned out well, dispose of the aiocb. */
1017 ret
= __aio_put_req(ctx
, iocb
);
1019 spin_unlock_irqrestore(&ctx
->ctx_lock
, flags
);
1021 if (waitqueue_active(&ctx
->wait
))
1022 wake_up(&ctx
->wait
);
1031 * Pull an event off of the ioctx's event ring. Returns the number of
1032 * events fetched (0 or 1 ;-)
1033 * FIXME: make this use cmpxchg.
1034 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1036 static int aio_read_evt(struct kioctx
*ioctx
, struct io_event
*ent
)
1038 struct aio_ring_info
*info
= &ioctx
->ring_info
;
1039 struct aio_ring
*ring
;
1043 ring
= kmap_atomic(info
->ring_pages
[0], KM_USER0
);
1044 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1045 (unsigned long)ring
->head
, (unsigned long)ring
->tail
,
1046 (unsigned long)ring
->nr
);
1048 if (ring
->head
== ring
->tail
)
1051 spin_lock(&info
->ring_lock
);
1053 head
= ring
->head
% info
->nr
;
1054 if (head
!= ring
->tail
) {
1055 struct io_event
*evp
= aio_ring_event(info
, head
, KM_USER1
);
1057 head
= (head
+ 1) % info
->nr
;
1058 smp_mb(); /* finish reading the event before updatng the head */
1061 put_aio_ring_event(evp
, KM_USER1
);
1063 spin_unlock(&info
->ring_lock
);
1066 kunmap_atomic(ring
, KM_USER0
);
1067 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret
,
1068 (unsigned long)ring
->head
, (unsigned long)ring
->tail
);
1072 struct aio_timeout
{
1073 struct timer_list timer
;
1075 struct task_struct
*p
;
1078 static void timeout_func(unsigned long data
)
1080 struct aio_timeout
*to
= (struct aio_timeout
*)data
;
1083 wake_up_process(to
->p
);
1086 static inline void init_timeout(struct aio_timeout
*to
)
1088 init_timer(&to
->timer
);
1089 to
->timer
.data
= (unsigned long)to
;
1090 to
->timer
.function
= timeout_func
;
1095 static inline void set_timeout(long start_jiffies
, struct aio_timeout
*to
,
1096 const struct timespec
*ts
)
1098 to
->timer
.expires
= start_jiffies
+ timespec_to_jiffies(ts
);
1099 if (time_after(to
->timer
.expires
, jiffies
))
1100 add_timer(&to
->timer
);
1105 static inline void clear_timeout(struct aio_timeout
*to
)
1107 del_singleshot_timer_sync(&to
->timer
);
1110 static int read_events(struct kioctx
*ctx
,
1111 long min_nr
, long nr
,
1112 struct io_event __user
*event
,
1113 struct timespec __user
*timeout
)
1115 long start_jiffies
= jiffies
;
1116 struct task_struct
*tsk
= current
;
1117 DECLARE_WAITQUEUE(wait
, tsk
);
1120 struct io_event ent
;
1121 struct aio_timeout to
;
1124 /* needed to zero any padding within an entry (there shouldn't be
1125 * any, but C is fun!
1127 memset(&ent
, 0, sizeof(ent
));
1130 while (likely(i
< nr
)) {
1131 ret
= aio_read_evt(ctx
, &ent
);
1132 if (unlikely(ret
<= 0))
1135 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1136 ent
.data
, ent
.obj
, ent
.res
, ent
.res2
);
1138 /* Could we split the check in two? */
1140 if (unlikely(copy_to_user(event
, &ent
, sizeof(ent
)))) {
1141 dprintk("aio: lost an event due to EFAULT.\n");
1146 /* Good, event copied to userland, update counts. */
1158 /* racey check, but it gets redone */
1159 if (!retry
&& unlikely(!list_empty(&ctx
->run_list
))) {
1161 aio_run_all_iocbs(ctx
);
1169 if (unlikely(copy_from_user(&ts
, timeout
, sizeof(ts
))))
1172 set_timeout(start_jiffies
, &to
, &ts
);
1175 while (likely(i
< nr
)) {
1176 add_wait_queue_exclusive(&ctx
->wait
, &wait
);
1178 set_task_state(tsk
, TASK_INTERRUPTIBLE
);
1179 ret
= aio_read_evt(ctx
, &ent
);
1185 if (to
.timed_out
) /* Only check after read evt */
1188 if (signal_pending(tsk
)) {
1192 /*ret = aio_read_evt(ctx, &ent);*/
1195 set_task_state(tsk
, TASK_RUNNING
);
1196 remove_wait_queue(&ctx
->wait
, &wait
);
1198 if (unlikely(ret
<= 0))
1202 if (unlikely(copy_to_user(event
, &ent
, sizeof(ent
)))) {
1203 dprintk("aio: lost an event due to EFAULT.\n");
1207 /* Good, event copied to userland, update counts. */
1218 /* Take an ioctx and remove it from the list of ioctx's. Protects
1219 * against races with itself via ->dead.
1221 static void io_destroy(struct kioctx
*ioctx
)
1223 struct mm_struct
*mm
= current
->mm
;
1224 struct kioctx
**tmp
;
1227 /* delete the entry from the list is someone else hasn't already */
1228 write_lock(&mm
->ioctx_list_lock
);
1229 was_dead
= ioctx
->dead
;
1231 for (tmp
= &mm
->ioctx_list
; *tmp
&& *tmp
!= ioctx
;
1232 tmp
= &(*tmp
)->next
)
1236 write_unlock(&mm
->ioctx_list_lock
);
1238 dprintk("aio_release(%p)\n", ioctx
);
1239 if (likely(!was_dead
))
1240 put_ioctx(ioctx
); /* twice for the list */
1242 aio_cancel_all(ioctx
);
1243 wait_for_all_aios(ioctx
);
1244 put_ioctx(ioctx
); /* once for the lookup */
1248 * Create an aio_context capable of receiving at least nr_events.
1249 * ctxp must not point to an aio_context that already exists, and
1250 * must be initialized to 0 prior to the call. On successful
1251 * creation of the aio_context, *ctxp is filled in with the resulting
1252 * handle. May fail with -EINVAL if *ctxp is not initialized,
1253 * if the specified nr_events exceeds internal limits. May fail
1254 * with -EAGAIN if the specified nr_events exceeds the user's limit
1255 * of available events. May fail with -ENOMEM if insufficient kernel
1256 * resources are available. May fail with -EFAULT if an invalid
1257 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1260 asmlinkage
long sys_io_setup(unsigned nr_events
, aio_context_t __user
*ctxp
)
1262 struct kioctx
*ioctx
= NULL
;
1266 ret
= get_user(ctx
, ctxp
);
1271 if (unlikely(ctx
|| nr_events
== 0)) {
1272 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1277 ioctx
= ioctx_alloc(nr_events
);
1278 ret
= PTR_ERR(ioctx
);
1279 if (!IS_ERR(ioctx
)) {
1280 ret
= put_user(ioctx
->user_id
, ctxp
);
1284 get_ioctx(ioctx
); /* io_destroy() expects us to hold a ref */
1293 * Destroy the aio_context specified. May cancel any outstanding
1294 * AIOs and block on completion. Will fail with -ENOSYS if not
1295 * implemented. May fail with -EFAULT if the context pointed to
1298 asmlinkage
long sys_io_destroy(aio_context_t ctx
)
1300 struct kioctx
*ioctx
= lookup_ioctx(ctx
);
1301 if (likely(NULL
!= ioctx
)) {
1305 pr_debug("EINVAL: io_destroy: invalid context id\n");
1310 * aio_p{read,write} are the default ki_retry methods for
1311 * IO_CMD_P{READ,WRITE}. They maintains kiocb retry state around potentially
1312 * multiple calls to f_op->aio_read(). They loop around partial progress
1313 * instead of returning -EIOCBRETRY because they don't have the means to call
1316 static ssize_t
aio_pread(struct kiocb
*iocb
)
1318 struct file
*file
= iocb
->ki_filp
;
1319 struct address_space
*mapping
= file
->f_mapping
;
1320 struct inode
*inode
= mapping
->host
;
1324 ret
= file
->f_op
->aio_read(iocb
, iocb
->ki_buf
,
1325 iocb
->ki_left
, iocb
->ki_pos
);
1327 * Can't just depend on iocb->ki_left to determine
1328 * whether we are done. This may have been a short read.
1331 iocb
->ki_buf
+= ret
;
1332 iocb
->ki_left
-= ret
;
1336 * For pipes and sockets we return once we have some data; for
1337 * regular files we retry till we complete the entire read or
1338 * find that we can't read any more data (e.g short reads).
1340 } while (ret
> 0 && iocb
->ki_left
> 0 &&
1341 !S_ISFIFO(inode
->i_mode
) && !S_ISSOCK(inode
->i_mode
));
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
;
1351 /* see aio_pread() */
1352 static ssize_t
aio_pwrite(struct kiocb
*iocb
)
1354 struct file
*file
= iocb
->ki_filp
;
1358 ret
= file
->f_op
->aio_write(iocb
, iocb
->ki_buf
,
1359 iocb
->ki_left
, iocb
->ki_pos
);
1361 iocb
->ki_buf
+= ret
;
1362 iocb
->ki_left
-= ret
;
1364 } while (ret
> 0 && iocb
->ki_left
> 0);
1366 if ((ret
== 0) || (iocb
->ki_left
== 0))
1367 ret
= iocb
->ki_nbytes
- iocb
->ki_left
;
1372 static ssize_t
aio_fdsync(struct kiocb
*iocb
)
1374 struct file
*file
= iocb
->ki_filp
;
1375 ssize_t ret
= -EINVAL
;
1377 if (file
->f_op
->aio_fsync
)
1378 ret
= file
->f_op
->aio_fsync(iocb
, 1);
1382 static ssize_t
aio_fsync(struct kiocb
*iocb
)
1384 struct file
*file
= iocb
->ki_filp
;
1385 ssize_t ret
= -EINVAL
;
1387 if (file
->f_op
->aio_fsync
)
1388 ret
= file
->f_op
->aio_fsync(iocb
, 0);
1394 * Performs the initial checks and aio retry method
1395 * setup for the kiocb at the time of io submission.
1397 static ssize_t
aio_setup_iocb(struct kiocb
*kiocb
)
1399 struct file
*file
= kiocb
->ki_filp
;
1402 switch (kiocb
->ki_opcode
) {
1403 case IOCB_CMD_PREAD
:
1405 if (unlikely(!(file
->f_mode
& FMODE_READ
)))
1408 if (unlikely(!access_ok(VERIFY_WRITE
, kiocb
->ki_buf
,
1411 ret
= security_file_permission(file
, MAY_READ
);
1415 if (file
->f_op
->aio_read
)
1416 kiocb
->ki_retry
= aio_pread
;
1418 case IOCB_CMD_PWRITE
:
1420 if (unlikely(!(file
->f_mode
& FMODE_WRITE
)))
1423 if (unlikely(!access_ok(VERIFY_READ
, kiocb
->ki_buf
,
1426 ret
= security_file_permission(file
, MAY_WRITE
);
1430 if (file
->f_op
->aio_write
)
1431 kiocb
->ki_retry
= aio_pwrite
;
1433 case IOCB_CMD_FDSYNC
:
1435 if (file
->f_op
->aio_fsync
)
1436 kiocb
->ki_retry
= aio_fdsync
;
1438 case IOCB_CMD_FSYNC
:
1440 if (file
->f_op
->aio_fsync
)
1441 kiocb
->ki_retry
= aio_fsync
;
1444 dprintk("EINVAL: io_submit: no operation provided\n");
1448 if (!kiocb
->ki_retry
)
1455 * aio_wake_function:
1456 * wait queue callback function for aio notification,
1457 * Simply triggers a retry of the operation via kick_iocb.
1459 * This callback is specified in the wait queue entry in
1460 * a kiocb (current->io_wait points to this wait queue
1461 * entry when an aio operation executes; it is used
1462 * instead of a synchronous wait when an i/o blocking
1463 * condition is encountered during aio).
1466 * This routine is executed with the wait queue lock held.
1467 * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
1468 * the ioctx lock inside the wait queue lock. This is safe
1469 * because this callback isn't used for wait queues which
1470 * are nested inside ioctx lock (i.e. ctx->wait)
1472 static int aio_wake_function(wait_queue_t
*wait
, unsigned mode
,
1473 int sync
, void *key
)
1475 struct kiocb
*iocb
= container_of(wait
, struct kiocb
, ki_wait
);
1477 list_del_init(&wait
->task_list
);
1482 int fastcall
io_submit_one(struct kioctx
*ctx
, struct iocb __user
*user_iocb
,
1489 /* enforce forwards compatibility on users */
1490 if (unlikely(iocb
->aio_reserved1
|| iocb
->aio_reserved2
||
1491 iocb
->aio_reserved3
)) {
1492 pr_debug("EINVAL: io_submit: reserve field set\n");
1496 /* prevent overflows */
1498 (iocb
->aio_buf
!= (unsigned long)iocb
->aio_buf
) ||
1499 (iocb
->aio_nbytes
!= (size_t)iocb
->aio_nbytes
) ||
1500 ((ssize_t
)iocb
->aio_nbytes
< 0)
1502 pr_debug("EINVAL: io_submit: overflow check\n");
1506 file
= fget(iocb
->aio_fildes
);
1507 if (unlikely(!file
))
1510 req
= aio_get_req(ctx
); /* returns with 2 references to req */
1511 if (unlikely(!req
)) {
1516 req
->ki_filp
= file
;
1517 ret
= put_user(req
->ki_key
, &user_iocb
->aio_key
);
1518 if (unlikely(ret
)) {
1519 dprintk("EFAULT: aio_key\n");
1523 req
->ki_obj
.user
= user_iocb
;
1524 req
->ki_user_data
= iocb
->aio_data
;
1525 req
->ki_pos
= iocb
->aio_offset
;
1527 req
->ki_buf
= (char __user
*)(unsigned long)iocb
->aio_buf
;
1528 req
->ki_left
= req
->ki_nbytes
= iocb
->aio_nbytes
;
1529 req
->ki_opcode
= iocb
->aio_lio_opcode
;
1530 init_waitqueue_func_entry(&req
->ki_wait
, aio_wake_function
);
1531 INIT_LIST_HEAD(&req
->ki_wait
.task_list
);
1532 req
->ki_retried
= 0;
1534 ret
= aio_setup_iocb(req
);
1539 spin_lock_irq(&ctx
->ctx_lock
);
1541 if (!list_empty(&ctx
->run_list
)) {
1542 /* drain the run list */
1543 while (__aio_run_iocbs(ctx
))
1546 spin_unlock_irq(&ctx
->ctx_lock
);
1547 aio_put_req(req
); /* drop extra ref to req */
1551 aio_put_req(req
); /* drop extra ref to req */
1552 aio_put_req(req
); /* drop i/o ref to req */
1557 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1558 * the number of iocbs queued. May return -EINVAL if the aio_context
1559 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1560 * *iocbpp[0] is not properly initialized, if the operation specified
1561 * is invalid for the file descriptor in the iocb. May fail with
1562 * -EFAULT if any of the data structures point to invalid data. May
1563 * fail with -EBADF if the file descriptor specified in the first
1564 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1565 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1566 * fail with -ENOSYS if not implemented.
1568 asmlinkage
long sys_io_submit(aio_context_t ctx_id
, long nr
,
1569 struct iocb __user
* __user
*iocbpp
)
1575 if (unlikely(nr
< 0))
1578 if (unlikely(!access_ok(VERIFY_READ
, iocbpp
, (nr
*sizeof(*iocbpp
)))))
1581 ctx
= lookup_ioctx(ctx_id
);
1582 if (unlikely(!ctx
)) {
1583 pr_debug("EINVAL: io_submit: invalid context id\n");
1588 * AKPM: should this return a partial result if some of the IOs were
1589 * successfully submitted?
1591 for (i
=0; i
<nr
; i
++) {
1592 struct iocb __user
*user_iocb
;
1595 if (unlikely(__get_user(user_iocb
, iocbpp
+ i
))) {
1600 if (unlikely(copy_from_user(&tmp
, user_iocb
, sizeof(tmp
)))) {
1605 ret
= io_submit_one(ctx
, user_iocb
, &tmp
);
1615 * Finds a given iocb for cancellation.
1616 * MUST be called with ctx->ctx_lock held.
1618 static struct kiocb
*lookup_kiocb(struct kioctx
*ctx
, struct iocb __user
*iocb
,
1621 struct list_head
*pos
;
1622 /* TODO: use a hash or array, this sucks. */
1623 list_for_each(pos
, &ctx
->active_reqs
) {
1624 struct kiocb
*kiocb
= list_kiocb(pos
);
1625 if (kiocb
->ki_obj
.user
== iocb
&& kiocb
->ki_key
== key
)
1632 * Attempts to cancel an iocb previously passed to io_submit. If
1633 * the operation is successfully cancelled, the resulting event is
1634 * copied into the memory pointed to by result without being placed
1635 * into the completion queue and 0 is returned. May fail with
1636 * -EFAULT if any of the data structures pointed to are invalid.
1637 * May fail with -EINVAL if aio_context specified by ctx_id is
1638 * invalid. May fail with -EAGAIN if the iocb specified was not
1639 * cancelled. Will fail with -ENOSYS if not implemented.
1641 asmlinkage
long sys_io_cancel(aio_context_t ctx_id
, struct iocb __user
*iocb
,
1642 struct io_event __user
*result
)
1644 int (*cancel
)(struct kiocb
*iocb
, struct io_event
*res
);
1646 struct kiocb
*kiocb
;
1650 ret
= get_user(key
, &iocb
->aio_key
);
1654 ctx
= lookup_ioctx(ctx_id
);
1658 spin_lock_irq(&ctx
->ctx_lock
);
1660 kiocb
= lookup_kiocb(ctx
, iocb
, key
);
1661 if (kiocb
&& kiocb
->ki_cancel
) {
1662 cancel
= kiocb
->ki_cancel
;
1664 kiocbSetCancelled(kiocb
);
1667 spin_unlock_irq(&ctx
->ctx_lock
);
1669 if (NULL
!= cancel
) {
1670 struct io_event tmp
;
1671 pr_debug("calling cancel\n");
1672 memset(&tmp
, 0, sizeof(tmp
));
1673 tmp
.obj
= (u64
)(unsigned long)kiocb
->ki_obj
.user
;
1674 tmp
.data
= kiocb
->ki_user_data
;
1675 ret
= cancel(kiocb
, &tmp
);
1677 /* Cancellation succeeded -- copy the result
1678 * into the user's buffer.
1680 if (copy_to_user(result
, &tmp
, sizeof(tmp
)))
1692 * Attempts to read at least min_nr events and up to nr events from
1693 * the completion queue for the aio_context specified by ctx_id. May
1694 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1695 * if nr is out of range, if when is out of range. May fail with
1696 * -EFAULT if any of the memory specified to is invalid. May return
1697 * 0 or < min_nr if no events are available and the timeout specified
1698 * by when has elapsed, where when == NULL specifies an infinite
1699 * timeout. Note that the timeout pointed to by when is relative and
1700 * will be updated if not NULL and the operation blocks. Will fail
1701 * with -ENOSYS if not implemented.
1703 asmlinkage
long sys_io_getevents(aio_context_t ctx_id
,
1706 struct io_event __user
*events
,
1707 struct timespec __user
*timeout
)
1709 struct kioctx
*ioctx
= lookup_ioctx(ctx_id
);
1712 if (likely(ioctx
)) {
1713 if (likely(min_nr
<= nr
&& min_nr
>= 0 && nr
>= 0))
1714 ret
= read_events(ioctx
, min_nr
, nr
, events
, timeout
);
1721 __initcall(aio_setup
);
1723 EXPORT_SYMBOL(aio_complete
);
1724 EXPORT_SYMBOL(aio_put_req
);
1725 EXPORT_SYMBOL(wait_on_sync_kiocb
);