Staging: remove at76_usb wireless driver.
[linux/fpc-iii.git] / fs / aio.c
blobd065b2c3273ea03615ae883558100b4962a2ddbb
1 /*
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>
18 #include <linux/uio.h>
20 #define DEBUG 0
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 #include <linux/eventfd.h>
35 #include <asm/kmap_types.h>
36 #include <asm/uaccess.h>
37 #include <asm/mmu_context.h>
39 #if DEBUG > 1
40 #define dprintk printk
41 #else
42 #define dprintk(x...) do { ; } while (0)
43 #endif
45 /*------ sysctl variables----*/
46 static DEFINE_SPINLOCK(aio_nr_lock);
47 unsigned long aio_nr; /* current system wide number of aio requests */
48 unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
49 /*----end sysctl variables---*/
51 static struct kmem_cache *kiocb_cachep;
52 static struct kmem_cache *kioctx_cachep;
54 static struct workqueue_struct *aio_wq;
56 /* Used for rare fput completion. */
57 static void aio_fput_routine(struct work_struct *);
58 static DECLARE_WORK(fput_work, aio_fput_routine);
60 static DEFINE_SPINLOCK(fput_lock);
61 static LIST_HEAD(fput_head);
63 static void aio_kick_handler(struct work_struct *);
64 static void aio_queue_work(struct kioctx *);
66 /* aio_setup
67 * Creates the slab caches used by the aio routines, panic on
68 * failure as this is done early during the boot sequence.
70 static int __init aio_setup(void)
72 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
73 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
75 aio_wq = create_workqueue("aio");
77 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
79 return 0;
82 static void aio_free_ring(struct kioctx *ctx)
84 struct aio_ring_info *info = &ctx->ring_info;
85 long i;
87 for (i=0; i<info->nr_pages; i++)
88 put_page(info->ring_pages[i]);
90 if (info->mmap_size) {
91 down_write(&ctx->mm->mmap_sem);
92 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
93 up_write(&ctx->mm->mmap_sem);
96 if (info->ring_pages && info->ring_pages != info->internal_pages)
97 kfree(info->ring_pages);
98 info->ring_pages = NULL;
99 info->nr = 0;
102 static int aio_setup_ring(struct kioctx *ctx)
104 struct aio_ring *ring;
105 struct aio_ring_info *info = &ctx->ring_info;
106 unsigned nr_events = ctx->max_reqs;
107 unsigned long size;
108 int nr_pages;
110 /* Compensate for the ring buffer's head/tail overlap entry */
111 nr_events += 2; /* 1 is required, 2 for good luck */
113 size = sizeof(struct aio_ring);
114 size += sizeof(struct io_event) * nr_events;
115 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
117 if (nr_pages < 0)
118 return -EINVAL;
120 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
122 info->nr = 0;
123 info->ring_pages = info->internal_pages;
124 if (nr_pages > AIO_RING_PAGES) {
125 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
126 if (!info->ring_pages)
127 return -ENOMEM;
130 info->mmap_size = nr_pages * PAGE_SIZE;
131 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
132 down_write(&ctx->mm->mmap_sem);
133 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
134 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
136 if (IS_ERR((void *)info->mmap_base)) {
137 up_write(&ctx->mm->mmap_sem);
138 info->mmap_size = 0;
139 aio_free_ring(ctx);
140 return -EAGAIN;
143 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
144 info->nr_pages = get_user_pages(current, ctx->mm,
145 info->mmap_base, nr_pages,
146 1, 0, info->ring_pages, NULL);
147 up_write(&ctx->mm->mmap_sem);
149 if (unlikely(info->nr_pages != nr_pages)) {
150 aio_free_ring(ctx);
151 return -EAGAIN;
154 ctx->user_id = info->mmap_base;
156 info->nr = nr_events; /* trusted copy */
158 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
159 ring->nr = nr_events; /* user copy */
160 ring->id = ctx->user_id;
161 ring->head = ring->tail = 0;
162 ring->magic = AIO_RING_MAGIC;
163 ring->compat_features = AIO_RING_COMPAT_FEATURES;
164 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
165 ring->header_length = sizeof(struct aio_ring);
166 kunmap_atomic(ring, KM_USER0);
168 return 0;
172 /* aio_ring_event: returns a pointer to the event at the given index from
173 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
175 #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
176 #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
177 #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
179 #define aio_ring_event(info, nr, km) ({ \
180 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
181 struct io_event *__event; \
182 __event = kmap_atomic( \
183 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
184 __event += pos % AIO_EVENTS_PER_PAGE; \
185 __event; \
188 #define put_aio_ring_event(event, km) do { \
189 struct io_event *__event = (event); \
190 (void)__event; \
191 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
192 } while(0)
194 static void ctx_rcu_free(struct rcu_head *head)
196 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
197 unsigned nr_events = ctx->max_reqs;
199 kmem_cache_free(kioctx_cachep, ctx);
201 if (nr_events) {
202 spin_lock(&aio_nr_lock);
203 BUG_ON(aio_nr - nr_events > aio_nr);
204 aio_nr -= nr_events;
205 spin_unlock(&aio_nr_lock);
209 /* __put_ioctx
210 * Called when the last user of an aio context has gone away,
211 * and the struct needs to be freed.
213 static void __put_ioctx(struct kioctx *ctx)
215 BUG_ON(ctx->reqs_active);
217 cancel_delayed_work(&ctx->wq);
218 cancel_work_sync(&ctx->wq.work);
219 aio_free_ring(ctx);
220 mmdrop(ctx->mm);
221 ctx->mm = NULL;
222 pr_debug("__put_ioctx: freeing %p\n", ctx);
223 call_rcu(&ctx->rcu_head, ctx_rcu_free);
226 #define get_ioctx(kioctx) do { \
227 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
228 atomic_inc(&(kioctx)->users); \
229 } while (0)
230 #define put_ioctx(kioctx) do { \
231 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
232 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
233 __put_ioctx(kioctx); \
234 } while (0)
236 /* ioctx_alloc
237 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
239 static struct kioctx *ioctx_alloc(unsigned nr_events)
241 struct mm_struct *mm;
242 struct kioctx *ctx;
243 int did_sync = 0;
245 /* Prevent overflows */
246 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
247 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
248 pr_debug("ENOMEM: nr_events too high\n");
249 return ERR_PTR(-EINVAL);
252 if ((unsigned long)nr_events > aio_max_nr)
253 return ERR_PTR(-EAGAIN);
255 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
256 if (!ctx)
257 return ERR_PTR(-ENOMEM);
259 ctx->max_reqs = nr_events;
260 mm = ctx->mm = current->mm;
261 atomic_inc(&mm->mm_count);
263 atomic_set(&ctx->users, 1);
264 spin_lock_init(&ctx->ctx_lock);
265 spin_lock_init(&ctx->ring_info.ring_lock);
266 init_waitqueue_head(&ctx->wait);
268 INIT_LIST_HEAD(&ctx->active_reqs);
269 INIT_LIST_HEAD(&ctx->run_list);
270 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
272 if (aio_setup_ring(ctx) < 0)
273 goto out_freectx;
275 /* limit the number of system wide aios */
276 do {
277 spin_lock_bh(&aio_nr_lock);
278 if (aio_nr + nr_events > aio_max_nr ||
279 aio_nr + nr_events < aio_nr)
280 ctx->max_reqs = 0;
281 else
282 aio_nr += ctx->max_reqs;
283 spin_unlock_bh(&aio_nr_lock);
284 if (ctx->max_reqs || did_sync)
285 break;
287 /* wait for rcu callbacks to have completed before giving up */
288 synchronize_rcu();
289 did_sync = 1;
290 ctx->max_reqs = nr_events;
291 } while (1);
293 if (ctx->max_reqs == 0)
294 goto out_cleanup;
296 /* now link into global list. */
297 spin_lock(&mm->ioctx_lock);
298 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
299 spin_unlock(&mm->ioctx_lock);
301 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
302 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
303 return ctx;
305 out_cleanup:
306 __put_ioctx(ctx);
307 return ERR_PTR(-EAGAIN);
309 out_freectx:
310 mmdrop(mm);
311 kmem_cache_free(kioctx_cachep, ctx);
312 ctx = ERR_PTR(-ENOMEM);
314 dprintk("aio: error allocating ioctx %p\n", ctx);
315 return ctx;
318 /* aio_cancel_all
319 * Cancels all outstanding aio requests on an aio context. Used
320 * when the processes owning a context have all exited to encourage
321 * the rapid destruction of the kioctx.
323 static void aio_cancel_all(struct kioctx *ctx)
325 int (*cancel)(struct kiocb *, struct io_event *);
326 struct io_event res;
327 spin_lock_irq(&ctx->ctx_lock);
328 ctx->dead = 1;
329 while (!list_empty(&ctx->active_reqs)) {
330 struct list_head *pos = ctx->active_reqs.next;
331 struct kiocb *iocb = list_kiocb(pos);
332 list_del_init(&iocb->ki_list);
333 cancel = iocb->ki_cancel;
334 kiocbSetCancelled(iocb);
335 if (cancel) {
336 iocb->ki_users++;
337 spin_unlock_irq(&ctx->ctx_lock);
338 cancel(iocb, &res);
339 spin_lock_irq(&ctx->ctx_lock);
342 spin_unlock_irq(&ctx->ctx_lock);
345 static void wait_for_all_aios(struct kioctx *ctx)
347 struct task_struct *tsk = current;
348 DECLARE_WAITQUEUE(wait, tsk);
350 spin_lock_irq(&ctx->ctx_lock);
351 if (!ctx->reqs_active)
352 goto out;
354 add_wait_queue(&ctx->wait, &wait);
355 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
356 while (ctx->reqs_active) {
357 spin_unlock_irq(&ctx->ctx_lock);
358 io_schedule();
359 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
360 spin_lock_irq(&ctx->ctx_lock);
362 __set_task_state(tsk, TASK_RUNNING);
363 remove_wait_queue(&ctx->wait, &wait);
365 out:
366 spin_unlock_irq(&ctx->ctx_lock);
369 /* wait_on_sync_kiocb:
370 * Waits on the given sync kiocb to complete.
372 ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
374 while (iocb->ki_users) {
375 set_current_state(TASK_UNINTERRUPTIBLE);
376 if (!iocb->ki_users)
377 break;
378 io_schedule();
380 __set_current_state(TASK_RUNNING);
381 return iocb->ki_user_data;
384 /* exit_aio: called when the last user of mm goes away. At this point,
385 * there is no way for any new requests to be submited or any of the
386 * io_* syscalls to be called on the context. However, there may be
387 * outstanding requests which hold references to the context; as they
388 * go away, they will call put_ioctx and release any pinned memory
389 * associated with the request (held via struct page * references).
391 void exit_aio(struct mm_struct *mm)
393 struct kioctx *ctx;
395 while (!hlist_empty(&mm->ioctx_list)) {
396 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
397 hlist_del_rcu(&ctx->list);
399 aio_cancel_all(ctx);
401 wait_for_all_aios(ctx);
403 * Ensure we don't leave the ctx on the aio_wq
405 cancel_work_sync(&ctx->wq.work);
407 if (1 != atomic_read(&ctx->users))
408 printk(KERN_DEBUG
409 "exit_aio:ioctx still alive: %d %d %d\n",
410 atomic_read(&ctx->users), ctx->dead,
411 ctx->reqs_active);
412 put_ioctx(ctx);
416 /* aio_get_req
417 * Allocate a slot for an aio request. Increments the users count
418 * of the kioctx so that the kioctx stays around until all requests are
419 * complete. Returns NULL if no requests are free.
421 * Returns with kiocb->users set to 2. The io submit code path holds
422 * an extra reference while submitting the i/o.
423 * This prevents races between the aio code path referencing the
424 * req (after submitting it) and aio_complete() freeing the req.
426 static struct kiocb *__aio_get_req(struct kioctx *ctx)
428 struct kiocb *req = NULL;
429 struct aio_ring *ring;
430 int okay = 0;
432 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
433 if (unlikely(!req))
434 return NULL;
436 req->ki_flags = 0;
437 req->ki_users = 2;
438 req->ki_key = 0;
439 req->ki_ctx = ctx;
440 req->ki_cancel = NULL;
441 req->ki_retry = NULL;
442 req->ki_dtor = NULL;
443 req->private = NULL;
444 req->ki_iovec = NULL;
445 INIT_LIST_HEAD(&req->ki_run_list);
446 req->ki_eventfd = NULL;
448 /* Check if the completion queue has enough free space to
449 * accept an event from this io.
451 spin_lock_irq(&ctx->ctx_lock);
452 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
453 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
454 list_add(&req->ki_list, &ctx->active_reqs);
455 ctx->reqs_active++;
456 okay = 1;
458 kunmap_atomic(ring, KM_USER0);
459 spin_unlock_irq(&ctx->ctx_lock);
461 if (!okay) {
462 kmem_cache_free(kiocb_cachep, req);
463 req = NULL;
466 return req;
469 static inline struct kiocb *aio_get_req(struct kioctx *ctx)
471 struct kiocb *req;
472 /* Handle a potential starvation case -- should be exceedingly rare as
473 * requests will be stuck on fput_head only if the aio_fput_routine is
474 * delayed and the requests were the last user of the struct file.
476 req = __aio_get_req(ctx);
477 if (unlikely(NULL == req)) {
478 aio_fput_routine(NULL);
479 req = __aio_get_req(ctx);
481 return req;
484 static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
486 assert_spin_locked(&ctx->ctx_lock);
488 if (req->ki_eventfd != NULL)
489 eventfd_ctx_put(req->ki_eventfd);
490 if (req->ki_dtor)
491 req->ki_dtor(req);
492 if (req->ki_iovec != &req->ki_inline_vec)
493 kfree(req->ki_iovec);
494 kmem_cache_free(kiocb_cachep, req);
495 ctx->reqs_active--;
497 if (unlikely(!ctx->reqs_active && ctx->dead))
498 wake_up(&ctx->wait);
501 static void aio_fput_routine(struct work_struct *data)
503 spin_lock_irq(&fput_lock);
504 while (likely(!list_empty(&fput_head))) {
505 struct kiocb *req = list_kiocb(fput_head.next);
506 struct kioctx *ctx = req->ki_ctx;
508 list_del(&req->ki_list);
509 spin_unlock_irq(&fput_lock);
511 /* Complete the fput(s) */
512 if (req->ki_filp != NULL)
513 __fput(req->ki_filp);
515 /* Link the iocb into the context's free list */
516 spin_lock_irq(&ctx->ctx_lock);
517 really_put_req(ctx, req);
518 spin_unlock_irq(&ctx->ctx_lock);
520 put_ioctx(ctx);
521 spin_lock_irq(&fput_lock);
523 spin_unlock_irq(&fput_lock);
526 /* __aio_put_req
527 * Returns true if this put was the last user of the request.
529 static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
531 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
532 req, atomic_long_read(&req->ki_filp->f_count));
534 assert_spin_locked(&ctx->ctx_lock);
536 req->ki_users--;
537 BUG_ON(req->ki_users < 0);
538 if (likely(req->ki_users))
539 return 0;
540 list_del(&req->ki_list); /* remove from active_reqs */
541 req->ki_cancel = NULL;
542 req->ki_retry = NULL;
545 * Try to optimize the aio and eventfd file* puts, by avoiding to
546 * schedule work in case it is not __fput() time. In normal cases,
547 * we would not be holding the last reference to the file*, so
548 * this function will be executed w/out any aio kthread wakeup.
550 if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) {
551 get_ioctx(ctx);
552 spin_lock(&fput_lock);
553 list_add(&req->ki_list, &fput_head);
554 spin_unlock(&fput_lock);
555 queue_work(aio_wq, &fput_work);
556 } else {
557 req->ki_filp = NULL;
558 really_put_req(ctx, req);
560 return 1;
563 /* aio_put_req
564 * Returns true if this put was the last user of the kiocb,
565 * false if the request is still in use.
567 int aio_put_req(struct kiocb *req)
569 struct kioctx *ctx = req->ki_ctx;
570 int ret;
571 spin_lock_irq(&ctx->ctx_lock);
572 ret = __aio_put_req(ctx, req);
573 spin_unlock_irq(&ctx->ctx_lock);
574 return ret;
577 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
579 struct mm_struct *mm = current->mm;
580 struct kioctx *ctx, *ret = NULL;
581 struct hlist_node *n;
583 rcu_read_lock();
585 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
586 if (ctx->user_id == ctx_id && !ctx->dead) {
587 get_ioctx(ctx);
588 ret = ctx;
589 break;
593 rcu_read_unlock();
594 return ret;
598 * use_mm
599 * Makes the calling kernel thread take on the specified
600 * mm context.
601 * Called by the retry thread execute retries within the
602 * iocb issuer's mm context, so that copy_from/to_user
603 * operations work seamlessly for aio.
604 * (Note: this routine is intended to be called only
605 * from a kernel thread context)
607 static void use_mm(struct mm_struct *mm)
609 struct mm_struct *active_mm;
610 struct task_struct *tsk = current;
612 task_lock(tsk);
613 active_mm = tsk->active_mm;
614 atomic_inc(&mm->mm_count);
615 tsk->mm = mm;
616 tsk->active_mm = mm;
617 switch_mm(active_mm, mm, tsk);
618 task_unlock(tsk);
620 mmdrop(active_mm);
624 * unuse_mm
625 * Reverses the effect of use_mm, i.e. releases the
626 * specified mm context which was earlier taken on
627 * by the calling kernel thread
628 * (Note: this routine is intended to be called only
629 * from a kernel thread context)
631 static void unuse_mm(struct mm_struct *mm)
633 struct task_struct *tsk = current;
635 task_lock(tsk);
636 tsk->mm = NULL;
637 /* active_mm is still 'mm' */
638 enter_lazy_tlb(mm, tsk);
639 task_unlock(tsk);
643 * Queue up a kiocb to be retried. Assumes that the kiocb
644 * has already been marked as kicked, and places it on
645 * the retry run list for the corresponding ioctx, if it
646 * isn't already queued. Returns 1 if it actually queued
647 * the kiocb (to tell the caller to activate the work
648 * queue to process it), or 0, if it found that it was
649 * already queued.
651 static inline int __queue_kicked_iocb(struct kiocb *iocb)
653 struct kioctx *ctx = iocb->ki_ctx;
655 assert_spin_locked(&ctx->ctx_lock);
657 if (list_empty(&iocb->ki_run_list)) {
658 list_add_tail(&iocb->ki_run_list,
659 &ctx->run_list);
660 return 1;
662 return 0;
665 /* aio_run_iocb
666 * This is the core aio execution routine. It is
667 * invoked both for initial i/o submission and
668 * subsequent retries via the aio_kick_handler.
669 * Expects to be invoked with iocb->ki_ctx->lock
670 * already held. The lock is released and reacquired
671 * as needed during processing.
673 * Calls the iocb retry method (already setup for the
674 * iocb on initial submission) for operation specific
675 * handling, but takes care of most of common retry
676 * execution details for a given iocb. The retry method
677 * needs to be non-blocking as far as possible, to avoid
678 * holding up other iocbs waiting to be serviced by the
679 * retry kernel thread.
681 * The trickier parts in this code have to do with
682 * ensuring that only one retry instance is in progress
683 * for a given iocb at any time. Providing that guarantee
684 * simplifies the coding of individual aio operations as
685 * it avoids various potential races.
687 static ssize_t aio_run_iocb(struct kiocb *iocb)
689 struct kioctx *ctx = iocb->ki_ctx;
690 ssize_t (*retry)(struct kiocb *);
691 ssize_t ret;
693 if (!(retry = iocb->ki_retry)) {
694 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
695 return 0;
699 * We don't want the next retry iteration for this
700 * operation to start until this one has returned and
701 * updated the iocb state. However, wait_queue functions
702 * can trigger a kick_iocb from interrupt context in the
703 * meantime, indicating that data is available for the next
704 * iteration. We want to remember that and enable the
705 * next retry iteration _after_ we are through with
706 * this one.
708 * So, in order to be able to register a "kick", but
709 * prevent it from being queued now, we clear the kick
710 * flag, but make the kick code *think* that the iocb is
711 * still on the run list until we are actually done.
712 * When we are done with this iteration, we check if
713 * the iocb was kicked in the meantime and if so, queue
714 * it up afresh.
717 kiocbClearKicked(iocb);
720 * This is so that aio_complete knows it doesn't need to
721 * pull the iocb off the run list (We can't just call
722 * INIT_LIST_HEAD because we don't want a kick_iocb to
723 * queue this on the run list yet)
725 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
726 spin_unlock_irq(&ctx->ctx_lock);
728 /* Quit retrying if the i/o has been cancelled */
729 if (kiocbIsCancelled(iocb)) {
730 ret = -EINTR;
731 aio_complete(iocb, ret, 0);
732 /* must not access the iocb after this */
733 goto out;
737 * Now we are all set to call the retry method in async
738 * context.
740 ret = retry(iocb);
742 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
743 BUG_ON(!list_empty(&iocb->ki_wait.task_list));
744 aio_complete(iocb, ret, 0);
746 out:
747 spin_lock_irq(&ctx->ctx_lock);
749 if (-EIOCBRETRY == ret) {
751 * OK, now that we are done with this iteration
752 * and know that there is more left to go,
753 * this is where we let go so that a subsequent
754 * "kick" can start the next iteration
757 /* will make __queue_kicked_iocb succeed from here on */
758 INIT_LIST_HEAD(&iocb->ki_run_list);
759 /* we must queue the next iteration ourselves, if it
760 * has already been kicked */
761 if (kiocbIsKicked(iocb)) {
762 __queue_kicked_iocb(iocb);
765 * __queue_kicked_iocb will always return 1 here, because
766 * iocb->ki_run_list is empty at this point so it should
767 * be safe to unconditionally queue the context into the
768 * work queue.
770 aio_queue_work(ctx);
773 return ret;
777 * __aio_run_iocbs:
778 * Process all pending retries queued on the ioctx
779 * run list.
780 * Assumes it is operating within the aio issuer's mm
781 * context.
783 static int __aio_run_iocbs(struct kioctx *ctx)
785 struct kiocb *iocb;
786 struct list_head run_list;
788 assert_spin_locked(&ctx->ctx_lock);
790 list_replace_init(&ctx->run_list, &run_list);
791 while (!list_empty(&run_list)) {
792 iocb = list_entry(run_list.next, struct kiocb,
793 ki_run_list);
794 list_del(&iocb->ki_run_list);
796 * Hold an extra reference while retrying i/o.
798 iocb->ki_users++; /* grab extra reference */
799 aio_run_iocb(iocb);
800 __aio_put_req(ctx, iocb);
802 if (!list_empty(&ctx->run_list))
803 return 1;
804 return 0;
807 static void aio_queue_work(struct kioctx * ctx)
809 unsigned long timeout;
811 * if someone is waiting, get the work started right
812 * away, otherwise, use a longer delay
814 smp_mb();
815 if (waitqueue_active(&ctx->wait))
816 timeout = 1;
817 else
818 timeout = HZ/10;
819 queue_delayed_work(aio_wq, &ctx->wq, timeout);
824 * aio_run_iocbs:
825 * Process all pending retries queued on the ioctx
826 * run list.
827 * Assumes it is operating within the aio issuer's mm
828 * context.
830 static inline void aio_run_iocbs(struct kioctx *ctx)
832 int requeue;
834 spin_lock_irq(&ctx->ctx_lock);
836 requeue = __aio_run_iocbs(ctx);
837 spin_unlock_irq(&ctx->ctx_lock);
838 if (requeue)
839 aio_queue_work(ctx);
843 * just like aio_run_iocbs, but keeps running them until
844 * the list stays empty
846 static inline void aio_run_all_iocbs(struct kioctx *ctx)
848 spin_lock_irq(&ctx->ctx_lock);
849 while (__aio_run_iocbs(ctx))
851 spin_unlock_irq(&ctx->ctx_lock);
855 * aio_kick_handler:
856 * Work queue handler triggered to process pending
857 * retries on an ioctx. Takes on the aio issuer's
858 * mm context before running the iocbs, so that
859 * copy_xxx_user operates on the issuer's address
860 * space.
861 * Run on aiod's context.
863 static void aio_kick_handler(struct work_struct *work)
865 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
866 mm_segment_t oldfs = get_fs();
867 struct mm_struct *mm;
868 int requeue;
870 set_fs(USER_DS);
871 use_mm(ctx->mm);
872 spin_lock_irq(&ctx->ctx_lock);
873 requeue =__aio_run_iocbs(ctx);
874 mm = ctx->mm;
875 spin_unlock_irq(&ctx->ctx_lock);
876 unuse_mm(mm);
877 set_fs(oldfs);
879 * we're in a worker thread already, don't use queue_delayed_work,
881 if (requeue)
882 queue_delayed_work(aio_wq, &ctx->wq, 0);
887 * Called by kick_iocb to queue the kiocb for retry
888 * and if required activate the aio work queue to process
889 * it
891 static void try_queue_kicked_iocb(struct kiocb *iocb)
893 struct kioctx *ctx = iocb->ki_ctx;
894 unsigned long flags;
895 int run = 0;
897 /* We're supposed to be the only path putting the iocb back on the run
898 * list. If we find that the iocb is *back* on a wait queue already
899 * than retry has happened before we could queue the iocb. This also
900 * means that the retry could have completed and freed our iocb, no
901 * good. */
902 BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
904 spin_lock_irqsave(&ctx->ctx_lock, flags);
905 /* set this inside the lock so that we can't race with aio_run_iocb()
906 * testing it and putting the iocb on the run list under the lock */
907 if (!kiocbTryKick(iocb))
908 run = __queue_kicked_iocb(iocb);
909 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
910 if (run)
911 aio_queue_work(ctx);
915 * kick_iocb:
916 * Called typically from a wait queue callback context
917 * (aio_wake_function) to trigger a retry of the iocb.
918 * The retry is usually executed by aio workqueue
919 * threads (See aio_kick_handler).
921 void kick_iocb(struct kiocb *iocb)
923 /* sync iocbs are easy: they can only ever be executing from a
924 * single context. */
925 if (is_sync_kiocb(iocb)) {
926 kiocbSetKicked(iocb);
927 wake_up_process(iocb->ki_obj.tsk);
928 return;
931 try_queue_kicked_iocb(iocb);
933 EXPORT_SYMBOL(kick_iocb);
935 /* aio_complete
936 * Called when the io request on the given iocb is complete.
937 * Returns true if this is the last user of the request. The
938 * only other user of the request can be the cancellation code.
940 int aio_complete(struct kiocb *iocb, long res, long res2)
942 struct kioctx *ctx = iocb->ki_ctx;
943 struct aio_ring_info *info;
944 struct aio_ring *ring;
945 struct io_event *event;
946 unsigned long flags;
947 unsigned long tail;
948 int ret;
951 * Special case handling for sync iocbs:
952 * - events go directly into the iocb for fast handling
953 * - the sync task with the iocb in its stack holds the single iocb
954 * ref, no other paths have a way to get another ref
955 * - the sync task helpfully left a reference to itself in the iocb
957 if (is_sync_kiocb(iocb)) {
958 BUG_ON(iocb->ki_users != 1);
959 iocb->ki_user_data = res;
960 iocb->ki_users = 0;
961 wake_up_process(iocb->ki_obj.tsk);
962 return 1;
965 info = &ctx->ring_info;
967 /* add a completion event to the ring buffer.
968 * must be done holding ctx->ctx_lock to prevent
969 * other code from messing with the tail
970 * pointer since we might be called from irq
971 * context.
973 spin_lock_irqsave(&ctx->ctx_lock, flags);
975 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
976 list_del_init(&iocb->ki_run_list);
979 * cancelled requests don't get events, userland was given one
980 * when the event got cancelled.
982 if (kiocbIsCancelled(iocb))
983 goto put_rq;
985 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
987 tail = info->tail;
988 event = aio_ring_event(info, tail, KM_IRQ0);
989 if (++tail >= info->nr)
990 tail = 0;
992 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
993 event->data = iocb->ki_user_data;
994 event->res = res;
995 event->res2 = res2;
997 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
998 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
999 res, res2);
1001 /* after flagging the request as done, we
1002 * must never even look at it again
1004 smp_wmb(); /* make event visible before updating tail */
1006 info->tail = tail;
1007 ring->tail = tail;
1009 put_aio_ring_event(event, KM_IRQ0);
1010 kunmap_atomic(ring, KM_IRQ1);
1012 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
1015 * Check if the user asked us to deliver the result through an
1016 * eventfd. The eventfd_signal() function is safe to be called
1017 * from IRQ context.
1019 if (iocb->ki_eventfd != NULL)
1020 eventfd_signal(iocb->ki_eventfd, 1);
1022 put_rq:
1023 /* everything turned out well, dispose of the aiocb. */
1024 ret = __aio_put_req(ctx, iocb);
1027 * We have to order our ring_info tail store above and test
1028 * of the wait list below outside the wait lock. This is
1029 * like in wake_up_bit() where clearing a bit has to be
1030 * ordered with the unlocked test.
1032 smp_mb();
1034 if (waitqueue_active(&ctx->wait))
1035 wake_up(&ctx->wait);
1037 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1038 return ret;
1041 /* aio_read_evt
1042 * Pull an event off of the ioctx's event ring. Returns the number of
1043 * events fetched (0 or 1 ;-)
1044 * FIXME: make this use cmpxchg.
1045 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1047 static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1049 struct aio_ring_info *info = &ioctx->ring_info;
1050 struct aio_ring *ring;
1051 unsigned long head;
1052 int ret = 0;
1054 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1055 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1056 (unsigned long)ring->head, (unsigned long)ring->tail,
1057 (unsigned long)ring->nr);
1059 if (ring->head == ring->tail)
1060 goto out;
1062 spin_lock(&info->ring_lock);
1064 head = ring->head % info->nr;
1065 if (head != ring->tail) {
1066 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1067 *ent = *evp;
1068 head = (head + 1) % info->nr;
1069 smp_mb(); /* finish reading the event before updatng the head */
1070 ring->head = head;
1071 ret = 1;
1072 put_aio_ring_event(evp, KM_USER1);
1074 spin_unlock(&info->ring_lock);
1076 out:
1077 kunmap_atomic(ring, KM_USER0);
1078 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1079 (unsigned long)ring->head, (unsigned long)ring->tail);
1080 return ret;
1083 struct aio_timeout {
1084 struct timer_list timer;
1085 int timed_out;
1086 struct task_struct *p;
1089 static void timeout_func(unsigned long data)
1091 struct aio_timeout *to = (struct aio_timeout *)data;
1093 to->timed_out = 1;
1094 wake_up_process(to->p);
1097 static inline void init_timeout(struct aio_timeout *to)
1099 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
1100 to->timed_out = 0;
1101 to->p = current;
1104 static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1105 const struct timespec *ts)
1107 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1108 if (time_after(to->timer.expires, jiffies))
1109 add_timer(&to->timer);
1110 else
1111 to->timed_out = 1;
1114 static inline void clear_timeout(struct aio_timeout *to)
1116 del_singleshot_timer_sync(&to->timer);
1119 static int read_events(struct kioctx *ctx,
1120 long min_nr, long nr,
1121 struct io_event __user *event,
1122 struct timespec __user *timeout)
1124 long start_jiffies = jiffies;
1125 struct task_struct *tsk = current;
1126 DECLARE_WAITQUEUE(wait, tsk);
1127 int ret;
1128 int i = 0;
1129 struct io_event ent;
1130 struct aio_timeout to;
1131 int retry = 0;
1133 /* needed to zero any padding within an entry (there shouldn't be
1134 * any, but C is fun!
1136 memset(&ent, 0, sizeof(ent));
1137 retry:
1138 ret = 0;
1139 while (likely(i < nr)) {
1140 ret = aio_read_evt(ctx, &ent);
1141 if (unlikely(ret <= 0))
1142 break;
1144 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1145 ent.data, ent.obj, ent.res, ent.res2);
1147 /* Could we split the check in two? */
1148 ret = -EFAULT;
1149 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1150 dprintk("aio: lost an event due to EFAULT.\n");
1151 break;
1153 ret = 0;
1155 /* Good, event copied to userland, update counts. */
1156 event ++;
1157 i ++;
1160 if (min_nr <= i)
1161 return i;
1162 if (ret)
1163 return ret;
1165 /* End fast path */
1167 /* racey check, but it gets redone */
1168 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1169 retry = 1;
1170 aio_run_all_iocbs(ctx);
1171 goto retry;
1174 init_timeout(&to);
1175 if (timeout) {
1176 struct timespec ts;
1177 ret = -EFAULT;
1178 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1179 goto out;
1181 set_timeout(start_jiffies, &to, &ts);
1184 while (likely(i < nr)) {
1185 add_wait_queue_exclusive(&ctx->wait, &wait);
1186 do {
1187 set_task_state(tsk, TASK_INTERRUPTIBLE);
1188 ret = aio_read_evt(ctx, &ent);
1189 if (ret)
1190 break;
1191 if (min_nr <= i)
1192 break;
1193 if (unlikely(ctx->dead)) {
1194 ret = -EINVAL;
1195 break;
1197 if (to.timed_out) /* Only check after read evt */
1198 break;
1199 /* Try to only show up in io wait if there are ops
1200 * in flight */
1201 if (ctx->reqs_active)
1202 io_schedule();
1203 else
1204 schedule();
1205 if (signal_pending(tsk)) {
1206 ret = -EINTR;
1207 break;
1209 /*ret = aio_read_evt(ctx, &ent);*/
1210 } while (1) ;
1212 set_task_state(tsk, TASK_RUNNING);
1213 remove_wait_queue(&ctx->wait, &wait);
1215 if (unlikely(ret <= 0))
1216 break;
1218 ret = -EFAULT;
1219 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1220 dprintk("aio: lost an event due to EFAULT.\n");
1221 break;
1224 /* Good, event copied to userland, update counts. */
1225 event ++;
1226 i ++;
1229 if (timeout)
1230 clear_timeout(&to);
1231 out:
1232 destroy_timer_on_stack(&to.timer);
1233 return i ? i : ret;
1236 /* Take an ioctx and remove it from the list of ioctx's. Protects
1237 * against races with itself via ->dead.
1239 static void io_destroy(struct kioctx *ioctx)
1241 struct mm_struct *mm = current->mm;
1242 int was_dead;
1244 /* delete the entry from the list is someone else hasn't already */
1245 spin_lock(&mm->ioctx_lock);
1246 was_dead = ioctx->dead;
1247 ioctx->dead = 1;
1248 hlist_del_rcu(&ioctx->list);
1249 spin_unlock(&mm->ioctx_lock);
1251 dprintk("aio_release(%p)\n", ioctx);
1252 if (likely(!was_dead))
1253 put_ioctx(ioctx); /* twice for the list */
1255 aio_cancel_all(ioctx);
1256 wait_for_all_aios(ioctx);
1259 * Wake up any waiters. The setting of ctx->dead must be seen
1260 * by other CPUs at this point. Right now, we rely on the
1261 * locking done by the above calls to ensure this consistency.
1263 wake_up(&ioctx->wait);
1264 put_ioctx(ioctx); /* once for the lookup */
1267 /* sys_io_setup:
1268 * Create an aio_context capable of receiving at least nr_events.
1269 * ctxp must not point to an aio_context that already exists, and
1270 * must be initialized to 0 prior to the call. On successful
1271 * creation of the aio_context, *ctxp is filled in with the resulting
1272 * handle. May fail with -EINVAL if *ctxp is not initialized,
1273 * if the specified nr_events exceeds internal limits. May fail
1274 * with -EAGAIN if the specified nr_events exceeds the user's limit
1275 * of available events. May fail with -ENOMEM if insufficient kernel
1276 * resources are available. May fail with -EFAULT if an invalid
1277 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1278 * implemented.
1280 SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1282 struct kioctx *ioctx = NULL;
1283 unsigned long ctx;
1284 long ret;
1286 ret = get_user(ctx, ctxp);
1287 if (unlikely(ret))
1288 goto out;
1290 ret = -EINVAL;
1291 if (unlikely(ctx || nr_events == 0)) {
1292 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1293 ctx, nr_events);
1294 goto out;
1297 ioctx = ioctx_alloc(nr_events);
1298 ret = PTR_ERR(ioctx);
1299 if (!IS_ERR(ioctx)) {
1300 ret = put_user(ioctx->user_id, ctxp);
1301 if (!ret)
1302 return 0;
1304 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1305 io_destroy(ioctx);
1308 out:
1309 return ret;
1312 /* sys_io_destroy:
1313 * Destroy the aio_context specified. May cancel any outstanding
1314 * AIOs and block on completion. Will fail with -ENOSYS if not
1315 * implemented. May fail with -EFAULT if the context pointed to
1316 * is invalid.
1318 SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1320 struct kioctx *ioctx = lookup_ioctx(ctx);
1321 if (likely(NULL != ioctx)) {
1322 io_destroy(ioctx);
1323 return 0;
1325 pr_debug("EINVAL: io_destroy: invalid context id\n");
1326 return -EINVAL;
1329 static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1331 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1333 BUG_ON(ret <= 0);
1335 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1336 ssize_t this = min((ssize_t)iov->iov_len, ret);
1337 iov->iov_base += this;
1338 iov->iov_len -= this;
1339 iocb->ki_left -= this;
1340 ret -= this;
1341 if (iov->iov_len == 0) {
1342 iocb->ki_cur_seg++;
1343 iov++;
1347 /* the caller should not have done more io than what fit in
1348 * the remaining iovecs */
1349 BUG_ON(ret > 0 && iocb->ki_left == 0);
1352 static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
1354 struct file *file = iocb->ki_filp;
1355 struct address_space *mapping = file->f_mapping;
1356 struct inode *inode = mapping->host;
1357 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1358 unsigned long, loff_t);
1359 ssize_t ret = 0;
1360 unsigned short opcode;
1362 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1363 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1364 rw_op = file->f_op->aio_read;
1365 opcode = IOCB_CMD_PREADV;
1366 } else {
1367 rw_op = file->f_op->aio_write;
1368 opcode = IOCB_CMD_PWRITEV;
1371 /* This matches the pread()/pwrite() logic */
1372 if (iocb->ki_pos < 0)
1373 return -EINVAL;
1375 do {
1376 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1377 iocb->ki_nr_segs - iocb->ki_cur_seg,
1378 iocb->ki_pos);
1379 if (ret > 0)
1380 aio_advance_iovec(iocb, ret);
1382 /* retry all partial writes. retry partial reads as long as its a
1383 * regular file. */
1384 } while (ret > 0 && iocb->ki_left > 0 &&
1385 (opcode == IOCB_CMD_PWRITEV ||
1386 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
1388 /* This means we must have transferred all that we could */
1389 /* No need to retry anymore */
1390 if ((ret == 0) || (iocb->ki_left == 0))
1391 ret = iocb->ki_nbytes - iocb->ki_left;
1393 /* If we managed to write some out we return that, rather than
1394 * the eventual error. */
1395 if (opcode == IOCB_CMD_PWRITEV
1396 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1397 && iocb->ki_nbytes - iocb->ki_left)
1398 ret = iocb->ki_nbytes - iocb->ki_left;
1400 return ret;
1403 static ssize_t aio_fdsync(struct kiocb *iocb)
1405 struct file *file = iocb->ki_filp;
1406 ssize_t ret = -EINVAL;
1408 if (file->f_op->aio_fsync)
1409 ret = file->f_op->aio_fsync(iocb, 1);
1410 return ret;
1413 static ssize_t aio_fsync(struct kiocb *iocb)
1415 struct file *file = iocb->ki_filp;
1416 ssize_t ret = -EINVAL;
1418 if (file->f_op->aio_fsync)
1419 ret = file->f_op->aio_fsync(iocb, 0);
1420 return ret;
1423 static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
1425 ssize_t ret;
1427 ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
1428 kiocb->ki_nbytes, 1,
1429 &kiocb->ki_inline_vec, &kiocb->ki_iovec);
1430 if (ret < 0)
1431 goto out;
1433 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1434 kiocb->ki_cur_seg = 0;
1435 /* ki_nbytes/left now reflect bytes instead of segs */
1436 kiocb->ki_nbytes = ret;
1437 kiocb->ki_left = ret;
1439 ret = 0;
1440 out:
1441 return ret;
1444 static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1446 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1447 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1448 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1449 kiocb->ki_nr_segs = 1;
1450 kiocb->ki_cur_seg = 0;
1451 return 0;
1455 * aio_setup_iocb:
1456 * Performs the initial checks and aio retry method
1457 * setup for the kiocb at the time of io submission.
1459 static ssize_t aio_setup_iocb(struct kiocb *kiocb)
1461 struct file *file = kiocb->ki_filp;
1462 ssize_t ret = 0;
1464 switch (kiocb->ki_opcode) {
1465 case IOCB_CMD_PREAD:
1466 ret = -EBADF;
1467 if (unlikely(!(file->f_mode & FMODE_READ)))
1468 break;
1469 ret = -EFAULT;
1470 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1471 kiocb->ki_left)))
1472 break;
1473 ret = security_file_permission(file, MAY_READ);
1474 if (unlikely(ret))
1475 break;
1476 ret = aio_setup_single_vector(kiocb);
1477 if (ret)
1478 break;
1479 ret = -EINVAL;
1480 if (file->f_op->aio_read)
1481 kiocb->ki_retry = aio_rw_vect_retry;
1482 break;
1483 case IOCB_CMD_PWRITE:
1484 ret = -EBADF;
1485 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1486 break;
1487 ret = -EFAULT;
1488 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1489 kiocb->ki_left)))
1490 break;
1491 ret = security_file_permission(file, MAY_WRITE);
1492 if (unlikely(ret))
1493 break;
1494 ret = aio_setup_single_vector(kiocb);
1495 if (ret)
1496 break;
1497 ret = -EINVAL;
1498 if (file->f_op->aio_write)
1499 kiocb->ki_retry = aio_rw_vect_retry;
1500 break;
1501 case IOCB_CMD_PREADV:
1502 ret = -EBADF;
1503 if (unlikely(!(file->f_mode & FMODE_READ)))
1504 break;
1505 ret = security_file_permission(file, MAY_READ);
1506 if (unlikely(ret))
1507 break;
1508 ret = aio_setup_vectored_rw(READ, kiocb);
1509 if (ret)
1510 break;
1511 ret = -EINVAL;
1512 if (file->f_op->aio_read)
1513 kiocb->ki_retry = aio_rw_vect_retry;
1514 break;
1515 case IOCB_CMD_PWRITEV:
1516 ret = -EBADF;
1517 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1518 break;
1519 ret = security_file_permission(file, MAY_WRITE);
1520 if (unlikely(ret))
1521 break;
1522 ret = aio_setup_vectored_rw(WRITE, kiocb);
1523 if (ret)
1524 break;
1525 ret = -EINVAL;
1526 if (file->f_op->aio_write)
1527 kiocb->ki_retry = aio_rw_vect_retry;
1528 break;
1529 case IOCB_CMD_FDSYNC:
1530 ret = -EINVAL;
1531 if (file->f_op->aio_fsync)
1532 kiocb->ki_retry = aio_fdsync;
1533 break;
1534 case IOCB_CMD_FSYNC:
1535 ret = -EINVAL;
1536 if (file->f_op->aio_fsync)
1537 kiocb->ki_retry = aio_fsync;
1538 break;
1539 default:
1540 dprintk("EINVAL: io_submit: no operation provided\n");
1541 ret = -EINVAL;
1544 if (!kiocb->ki_retry)
1545 return ret;
1547 return 0;
1551 * aio_wake_function:
1552 * wait queue callback function for aio notification,
1553 * Simply triggers a retry of the operation via kick_iocb.
1555 * This callback is specified in the wait queue entry in
1556 * a kiocb.
1558 * Note:
1559 * This routine is executed with the wait queue lock held.
1560 * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
1561 * the ioctx lock inside the wait queue lock. This is safe
1562 * because this callback isn't used for wait queues which
1563 * are nested inside ioctx lock (i.e. ctx->wait)
1565 static int aio_wake_function(wait_queue_t *wait, unsigned mode,
1566 int sync, void *key)
1568 struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
1570 list_del_init(&wait->task_list);
1571 kick_iocb(iocb);
1572 return 1;
1575 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1576 struct iocb *iocb)
1578 struct kiocb *req;
1579 struct file *file;
1580 ssize_t ret;
1582 /* enforce forwards compatibility on users */
1583 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
1584 pr_debug("EINVAL: io_submit: reserve field set\n");
1585 return -EINVAL;
1588 /* prevent overflows */
1589 if (unlikely(
1590 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1591 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1592 ((ssize_t)iocb->aio_nbytes < 0)
1593 )) {
1594 pr_debug("EINVAL: io_submit: overflow check\n");
1595 return -EINVAL;
1598 file = fget(iocb->aio_fildes);
1599 if (unlikely(!file))
1600 return -EBADF;
1602 req = aio_get_req(ctx); /* returns with 2 references to req */
1603 if (unlikely(!req)) {
1604 fput(file);
1605 return -EAGAIN;
1607 req->ki_filp = file;
1608 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1610 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1611 * instance of the file* now. The file descriptor must be
1612 * an eventfd() fd, and will be signaled for each completed
1613 * event using the eventfd_signal() function.
1615 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
1616 if (IS_ERR(req->ki_eventfd)) {
1617 ret = PTR_ERR(req->ki_eventfd);
1618 req->ki_eventfd = NULL;
1619 goto out_put_req;
1623 ret = put_user(req->ki_key, &user_iocb->aio_key);
1624 if (unlikely(ret)) {
1625 dprintk("EFAULT: aio_key\n");
1626 goto out_put_req;
1629 req->ki_obj.user = user_iocb;
1630 req->ki_user_data = iocb->aio_data;
1631 req->ki_pos = iocb->aio_offset;
1633 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1634 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1635 req->ki_opcode = iocb->aio_lio_opcode;
1636 init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
1637 INIT_LIST_HEAD(&req->ki_wait.task_list);
1639 ret = aio_setup_iocb(req);
1641 if (ret)
1642 goto out_put_req;
1644 spin_lock_irq(&ctx->ctx_lock);
1645 aio_run_iocb(req);
1646 if (!list_empty(&ctx->run_list)) {
1647 /* drain the run list */
1648 while (__aio_run_iocbs(ctx))
1651 spin_unlock_irq(&ctx->ctx_lock);
1652 aio_put_req(req); /* drop extra ref to req */
1653 return 0;
1655 out_put_req:
1656 aio_put_req(req); /* drop extra ref to req */
1657 aio_put_req(req); /* drop i/o ref to req */
1658 return ret;
1661 /* sys_io_submit:
1662 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1663 * the number of iocbs queued. May return -EINVAL if the aio_context
1664 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1665 * *iocbpp[0] is not properly initialized, if the operation specified
1666 * is invalid for the file descriptor in the iocb. May fail with
1667 * -EFAULT if any of the data structures point to invalid data. May
1668 * fail with -EBADF if the file descriptor specified in the first
1669 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1670 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1671 * fail with -ENOSYS if not implemented.
1673 SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1674 struct iocb __user * __user *, iocbpp)
1676 struct kioctx *ctx;
1677 long ret = 0;
1678 int i;
1680 if (unlikely(nr < 0))
1681 return -EINVAL;
1683 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1684 return -EFAULT;
1686 ctx = lookup_ioctx(ctx_id);
1687 if (unlikely(!ctx)) {
1688 pr_debug("EINVAL: io_submit: invalid context id\n");
1689 return -EINVAL;
1693 * AKPM: should this return a partial result if some of the IOs were
1694 * successfully submitted?
1696 for (i=0; i<nr; i++) {
1697 struct iocb __user *user_iocb;
1698 struct iocb tmp;
1700 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1701 ret = -EFAULT;
1702 break;
1705 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1706 ret = -EFAULT;
1707 break;
1710 ret = io_submit_one(ctx, user_iocb, &tmp);
1711 if (ret)
1712 break;
1715 put_ioctx(ctx);
1716 return i ? i : ret;
1719 /* lookup_kiocb
1720 * Finds a given iocb for cancellation.
1722 static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1723 u32 key)
1725 struct list_head *pos;
1727 assert_spin_locked(&ctx->ctx_lock);
1729 /* TODO: use a hash or array, this sucks. */
1730 list_for_each(pos, &ctx->active_reqs) {
1731 struct kiocb *kiocb = list_kiocb(pos);
1732 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1733 return kiocb;
1735 return NULL;
1738 /* sys_io_cancel:
1739 * Attempts to cancel an iocb previously passed to io_submit. If
1740 * the operation is successfully cancelled, the resulting event is
1741 * copied into the memory pointed to by result without being placed
1742 * into the completion queue and 0 is returned. May fail with
1743 * -EFAULT if any of the data structures pointed to are invalid.
1744 * May fail with -EINVAL if aio_context specified by ctx_id is
1745 * invalid. May fail with -EAGAIN if the iocb specified was not
1746 * cancelled. Will fail with -ENOSYS if not implemented.
1748 SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1749 struct io_event __user *, result)
1751 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1752 struct kioctx *ctx;
1753 struct kiocb *kiocb;
1754 u32 key;
1755 int ret;
1757 ret = get_user(key, &iocb->aio_key);
1758 if (unlikely(ret))
1759 return -EFAULT;
1761 ctx = lookup_ioctx(ctx_id);
1762 if (unlikely(!ctx))
1763 return -EINVAL;
1765 spin_lock_irq(&ctx->ctx_lock);
1766 ret = -EAGAIN;
1767 kiocb = lookup_kiocb(ctx, iocb, key);
1768 if (kiocb && kiocb->ki_cancel) {
1769 cancel = kiocb->ki_cancel;
1770 kiocb->ki_users ++;
1771 kiocbSetCancelled(kiocb);
1772 } else
1773 cancel = NULL;
1774 spin_unlock_irq(&ctx->ctx_lock);
1776 if (NULL != cancel) {
1777 struct io_event tmp;
1778 pr_debug("calling cancel\n");
1779 memset(&tmp, 0, sizeof(tmp));
1780 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1781 tmp.data = kiocb->ki_user_data;
1782 ret = cancel(kiocb, &tmp);
1783 if (!ret) {
1784 /* Cancellation succeeded -- copy the result
1785 * into the user's buffer.
1787 if (copy_to_user(result, &tmp, sizeof(tmp)))
1788 ret = -EFAULT;
1790 } else
1791 ret = -EINVAL;
1793 put_ioctx(ctx);
1795 return ret;
1798 /* io_getevents:
1799 * Attempts to read at least min_nr events and up to nr events from
1800 * the completion queue for the aio_context specified by ctx_id. May
1801 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1802 * if nr is out of range, if when is out of range. May fail with
1803 * -EFAULT if any of the memory specified to is invalid. May return
1804 * 0 or < min_nr if no events are available and the timeout specified
1805 * by when has elapsed, where when == NULL specifies an infinite
1806 * timeout. Note that the timeout pointed to by when is relative and
1807 * will be updated if not NULL and the operation blocks. Will fail
1808 * with -ENOSYS if not implemented.
1810 SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1811 long, min_nr,
1812 long, nr,
1813 struct io_event __user *, events,
1814 struct timespec __user *, timeout)
1816 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1817 long ret = -EINVAL;
1819 if (likely(ioctx)) {
1820 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1821 ret = read_events(ioctx, min_nr, nr, events, timeout);
1822 put_ioctx(ioctx);
1825 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
1826 return ret;
1829 __initcall(aio_setup);
1831 EXPORT_SYMBOL(aio_complete);
1832 EXPORT_SYMBOL(aio_put_req);
1833 EXPORT_SYMBOL(wait_on_sync_kiocb);