blob: 632b235f4fbe02c237de17fbde271c8bfe6f1240 [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>
Jens Axboeb9d128f2009-10-29 13:59:26 +010018#include <linux/backing-dev.h>
Badari Pulavarty027445c2006-09-30 23:28:46 -070019#include <linux/uio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
21#define DEBUG 0
22
23#include <linux/sched.h>
24#include <linux/fs.h>
25#include <linux/file.h>
26#include <linux/mm.h>
27#include <linux/mman.h>
Michael S. Tsirkin3d2d8272009-09-21 17:03:51 -070028#include <linux/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/slab.h>
30#include <linux/timer.h>
31#include <linux/aio.h>
32#include <linux/highmem.h>
33#include <linux/workqueue.h>
34#include <linux/security.h>
Davide Libenzi9c3060b2007-05-10 22:23:21 -070035#include <linux/eventfd.h>
Jeff Moyercfb1e332009-10-02 18:57:36 -040036#include <linux/blkdev.h>
Jeff Moyer9d85cba2010-05-26 14:44:26 -070037#include <linux/compat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39#include <asm/kmap_types.h>
40#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42#if DEBUG > 1
43#define dprintk printk
44#else
45#define dprintk(x...) do { ; } while (0)
46#endif
47
Linus Torvalds1da177e2005-04-16 15:20:36 -070048/*------ sysctl variables----*/
Zach Brownd55b5fd2005-11-07 00:59:31 -080049static DEFINE_SPINLOCK(aio_nr_lock);
50unsigned long aio_nr; /* current system wide number of aio requests */
51unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
Linus Torvalds1da177e2005-04-16 15:20:36 -070052/*----end sysctl variables---*/
53
Christoph Lametere18b8902006-12-06 20:33:20 -080054static struct kmem_cache *kiocb_cachep;
55static struct kmem_cache *kioctx_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57static struct workqueue_struct *aio_wq;
58
59/* Used for rare fput completion. */
David Howells65f27f32006-11-22 14:55:48 +000060static void aio_fput_routine(struct work_struct *);
61static DECLARE_WORK(fput_work, aio_fput_routine);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63static DEFINE_SPINLOCK(fput_lock);
Adrian Bunk25ee7e32005-04-25 08:18:14 -070064static LIST_HEAD(fput_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
David Howells65f27f32006-11-22 14:55:48 +000066static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070067static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69/* aio_setup
70 * Creates the slab caches used by the aio routines, panic on
71 * failure as this is done early during the boot sequence.
72 */
73static int __init aio_setup(void)
74{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070075 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
76 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Tejun Heod37adaa2011-01-26 17:42:27 +010078 aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */
Jens Axboecf159002011-03-02 20:12:18 -050079 BUG_ON(!aio_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
82
83 return 0;
84}
H Hartley Sweeten385773e2009-09-22 16:43:53 -070085__initcall(aio_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87static void aio_free_ring(struct kioctx *ctx)
88{
89 struct aio_ring_info *info = &ctx->ring_info;
90 long i;
91
92 for (i=0; i<info->nr_pages; i++)
93 put_page(info->ring_pages[i]);
94
95 if (info->mmap_size) {
96 down_write(&ctx->mm->mmap_sem);
97 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
98 up_write(&ctx->mm->mmap_sem);
99 }
100
101 if (info->ring_pages && info->ring_pages != info->internal_pages)
102 kfree(info->ring_pages);
103 info->ring_pages = NULL;
104 info->nr = 0;
105}
106
107static int aio_setup_ring(struct kioctx *ctx)
108{
109 struct aio_ring *ring;
110 struct aio_ring_info *info = &ctx->ring_info;
111 unsigned nr_events = ctx->max_reqs;
112 unsigned long size;
113 int nr_pages;
114
115 /* Compensate for the ring buffer's head/tail overlap entry */
116 nr_events += 2; /* 1 is required, 2 for good luck */
117
118 size = sizeof(struct aio_ring);
119 size += sizeof(struct io_event) * nr_events;
120 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
121
122 if (nr_pages < 0)
123 return -EINVAL;
124
125 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
126
127 info->nr = 0;
128 info->ring_pages = info->internal_pages;
129 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800130 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (!info->ring_pages)
132 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134
135 info->mmap_size = nr_pages * PAGE_SIZE;
136 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
137 down_write(&ctx->mm->mmap_sem);
138 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
Robert P. J. Daye10a4432007-02-10 01:42:56 -0800139 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 0);
141 if (IS_ERR((void *)info->mmap_base)) {
142 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 info->mmap_size = 0;
144 aio_free_ring(ctx);
145 return -EAGAIN;
146 }
147
148 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
149 info->nr_pages = get_user_pages(current, ctx->mm,
150 info->mmap_base, nr_pages,
151 1, 0, info->ring_pages, NULL);
152 up_write(&ctx->mm->mmap_sem);
153
154 if (unlikely(info->nr_pages != nr_pages)) {
155 aio_free_ring(ctx);
156 return -EAGAIN;
157 }
158
159 ctx->user_id = info->mmap_base;
160
161 info->nr = nr_events; /* trusted copy */
162
163 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
164 ring->nr = nr_events; /* user copy */
165 ring->id = ctx->user_id;
166 ring->head = ring->tail = 0;
167 ring->magic = AIO_RING_MAGIC;
168 ring->compat_features = AIO_RING_COMPAT_FEATURES;
169 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
170 ring->header_length = sizeof(struct aio_ring);
171 kunmap_atomic(ring, KM_USER0);
172
173 return 0;
174}
175
176
177/* aio_ring_event: returns a pointer to the event at the given index from
178 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
179 */
180#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
181#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
182#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
183
184#define aio_ring_event(info, nr, km) ({ \
185 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
186 struct io_event *__event; \
187 __event = kmap_atomic( \
188 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
189 __event += pos % AIO_EVENTS_PER_PAGE; \
190 __event; \
191})
192
193#define put_aio_ring_event(event, km) do { \
194 struct io_event *__event = (event); \
195 (void)__event; \
196 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
197} while(0)
198
Jens Axboeabf137d2008-12-09 08:11:22 +0100199static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700200{
Jens Axboeabf137d2008-12-09 08:11:22 +0100201 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700202 unsigned nr_events = ctx->max_reqs;
203
Adrian Bunkd5470b52008-04-29 00:58:57 -0700204 kmem_cache_free(kioctx_cachep, ctx);
205
206 if (nr_events) {
207 spin_lock(&aio_nr_lock);
208 BUG_ON(aio_nr - nr_events > aio_nr);
209 aio_nr -= nr_events;
210 spin_unlock(&aio_nr_lock);
211 }
212}
213
Jens Axboeabf137d2008-12-09 08:11:22 +0100214/* __put_ioctx
215 * Called when the last user of an aio context has gone away,
216 * and the struct needs to be freed.
217 */
218static void __put_ioctx(struct kioctx *ctx)
219{
220 BUG_ON(ctx->reqs_active);
221
222 cancel_delayed_work(&ctx->wq);
223 cancel_work_sync(&ctx->wq.work);
224 aio_free_ring(ctx);
225 mmdrop(ctx->mm);
226 ctx->mm = NULL;
227 pr_debug("__put_ioctx: freeing %p\n", ctx);
228 call_rcu(&ctx->rcu_head, ctx_rcu_free);
229}
230
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800231static inline void get_ioctx(struct kioctx *kioctx)
232{
233 BUG_ON(atomic_read(&kioctx->users) <= 0);
234 atomic_inc(&kioctx->users);
235}
236
237static inline int try_get_ioctx(struct kioctx *kioctx)
238{
239 return atomic_inc_not_zero(&kioctx->users);
240}
241
242static inline void put_ioctx(struct kioctx *kioctx)
243{
244 BUG_ON(atomic_read(&kioctx->users) <= 0);
245 if (unlikely(atomic_dec_and_test(&kioctx->users)))
246 __put_ioctx(kioctx);
247}
Adrian Bunkd5470b52008-04-29 00:58:57 -0700248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249/* ioctx_alloc
250 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
251 */
252static struct kioctx *ioctx_alloc(unsigned nr_events)
253{
254 struct mm_struct *mm;
255 struct kioctx *ctx;
Jens Axboeabf137d2008-12-09 08:11:22 +0100256 int did_sync = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 /* Prevent overflows */
259 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
260 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
261 pr_debug("ENOMEM: nr_events too high\n");
262 return ERR_PTR(-EINVAL);
263 }
264
Zach Brownd55b5fd2005-11-07 00:59:31 -0800265 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 return ERR_PTR(-EAGAIN);
267
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800268 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 if (!ctx)
270 return ERR_PTR(-ENOMEM);
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 ctx->max_reqs = nr_events;
273 mm = ctx->mm = current->mm;
274 atomic_inc(&mm->mm_count);
275
276 atomic_set(&ctx->users, 1);
277 spin_lock_init(&ctx->ctx_lock);
278 spin_lock_init(&ctx->ring_info.ring_lock);
279 init_waitqueue_head(&ctx->wait);
280
281 INIT_LIST_HEAD(&ctx->active_reqs);
282 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000283 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
285 if (aio_setup_ring(ctx) < 0)
286 goto out_freectx;
287
288 /* limit the number of system wide aios */
Jens Axboeabf137d2008-12-09 08:11:22 +0100289 do {
290 spin_lock_bh(&aio_nr_lock);
291 if (aio_nr + nr_events > aio_max_nr ||
292 aio_nr + nr_events < aio_nr)
293 ctx->max_reqs = 0;
294 else
295 aio_nr += ctx->max_reqs;
296 spin_unlock_bh(&aio_nr_lock);
297 if (ctx->max_reqs || did_sync)
298 break;
299
300 /* wait for rcu callbacks to have completed before giving up */
301 synchronize_rcu();
302 did_sync = 1;
303 ctx->max_reqs = nr_events;
304 } while (1);
305
Zach Brownd55b5fd2005-11-07 00:59:31 -0800306 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 goto out_cleanup;
308
Jeff Moyer39fa0032008-04-29 01:03:48 -0700309 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100310 spin_lock(&mm->ioctx_lock);
311 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
312 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
314 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
315 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
316 return ctx;
317
318out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 __put_ioctx(ctx);
320 return ERR_PTR(-EAGAIN);
321
322out_freectx:
323 mmdrop(mm);
324 kmem_cache_free(kioctx_cachep, ctx);
325 ctx = ERR_PTR(-ENOMEM);
326
327 dprintk("aio: error allocating ioctx %p\n", ctx);
328 return ctx;
329}
330
331/* aio_cancel_all
332 * Cancels all outstanding aio requests on an aio context. Used
333 * when the processes owning a context have all exited to encourage
334 * the rapid destruction of the kioctx.
335 */
336static void aio_cancel_all(struct kioctx *ctx)
337{
338 int (*cancel)(struct kiocb *, struct io_event *);
339 struct io_event res;
340 spin_lock_irq(&ctx->ctx_lock);
341 ctx->dead = 1;
342 while (!list_empty(&ctx->active_reqs)) {
343 struct list_head *pos = ctx->active_reqs.next;
344 struct kiocb *iocb = list_kiocb(pos);
345 list_del_init(&iocb->ki_list);
346 cancel = iocb->ki_cancel;
347 kiocbSetCancelled(iocb);
348 if (cancel) {
349 iocb->ki_users++;
350 spin_unlock_irq(&ctx->ctx_lock);
351 cancel(iocb, &res);
352 spin_lock_irq(&ctx->ctx_lock);
353 }
354 }
355 spin_unlock_irq(&ctx->ctx_lock);
356}
357
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700358static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359{
360 struct task_struct *tsk = current;
361 DECLARE_WAITQUEUE(wait, tsk);
362
Ken Chendee11c22007-02-03 01:13:45 -0800363 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800365 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
367 add_wait_queue(&ctx->wait, &wait);
368 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
369 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800370 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700371 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800373 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 }
375 __set_task_state(tsk, TASK_RUNNING);
376 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800377
378out:
379 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380}
381
382/* wait_on_sync_kiocb:
383 * Waits on the given sync kiocb to complete.
384 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800385ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386{
387 while (iocb->ki_users) {
388 set_current_state(TASK_UNINTERRUPTIBLE);
389 if (!iocb->ki_users)
390 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700391 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 }
393 __set_current_state(TASK_RUNNING);
394 return iocb->ki_user_data;
395}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700396EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
398/* exit_aio: called when the last user of mm goes away. At this point,
399 * there is no way for any new requests to be submited or any of the
400 * io_* syscalls to be called on the context. However, there may be
401 * outstanding requests which hold references to the context; as they
402 * go away, they will call put_ioctx and release any pinned memory
403 * associated with the request (held via struct page * references).
404 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800405void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406{
Jens Axboeabf137d2008-12-09 08:11:22 +0100407 struct kioctx *ctx;
408
409 while (!hlist_empty(&mm->ioctx_list)) {
410 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
411 hlist_del_rcu(&ctx->list);
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 aio_cancel_all(ctx);
414
415 wait_for_all_aios(ctx);
416 /*
Andrew Mortona9df62c2007-05-09 02:33:54 -0700417 * Ensure we don't leave the ctx on the aio_wq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 */
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700419 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420
421 if (1 != atomic_read(&ctx->users))
422 printk(KERN_DEBUG
423 "exit_aio:ioctx still alive: %d %d %d\n",
424 atomic_read(&ctx->users), ctx->dead,
425 ctx->reqs_active);
426 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 }
428}
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430/* aio_get_req
431 * Allocate a slot for an aio request. Increments the users count
432 * of the kioctx so that the kioctx stays around until all requests are
433 * complete. Returns NULL if no requests are free.
434 *
435 * Returns with kiocb->users set to 2. The io submit code path holds
436 * an extra reference while submitting the i/o.
437 * This prevents races between the aio code path referencing the
438 * req (after submitting it) and aio_complete() freeing the req.
439 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800440static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441{
442 struct kiocb *req = NULL;
443 struct aio_ring *ring;
444 int okay = 0;
445
446 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
447 if (unlikely(!req))
448 return NULL;
449
Zach Brown4faa5282005-10-17 16:43:33 -0700450 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 req->ki_users = 2;
452 req->ki_key = 0;
453 req->ki_ctx = ctx;
454 req->ki_cancel = NULL;
455 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 req->ki_dtor = NULL;
457 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700458 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700460 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
462 /* Check if the completion queue has enough free space to
463 * accept an event from this io.
464 */
465 spin_lock_irq(&ctx->ctx_lock);
466 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
467 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
468 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 ctx->reqs_active++;
470 okay = 1;
471 }
472 kunmap_atomic(ring, KM_USER0);
473 spin_unlock_irq(&ctx->ctx_lock);
474
475 if (!okay) {
476 kmem_cache_free(kiocb_cachep, req);
477 req = NULL;
478 }
479
480 return req;
481}
482
483static inline struct kiocb *aio_get_req(struct kioctx *ctx)
484{
485 struct kiocb *req;
486 /* Handle a potential starvation case -- should be exceedingly rare as
487 * requests will be stuck on fput_head only if the aio_fput_routine is
488 * delayed and the requests were the last user of the struct file.
489 */
490 req = __aio_get_req(ctx);
491 if (unlikely(NULL == req)) {
492 aio_fput_routine(NULL);
493 req = __aio_get_req(ctx);
494 }
495 return req;
496}
497
498static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
499{
Zach Brownd00689a2005-11-13 16:07:34 -0800500 assert_spin_locked(&ctx->ctx_lock);
501
Davide Libenzi13389012009-06-30 11:41:11 -0700502 if (req->ki_eventfd != NULL)
503 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 if (req->ki_dtor)
505 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700506 if (req->ki_iovec != &req->ki_inline_vec)
507 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 kmem_cache_free(kiocb_cachep, req);
509 ctx->reqs_active--;
510
511 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700512 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513}
514
David Howells65f27f32006-11-22 14:55:48 +0000515static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516{
517 spin_lock_irq(&fput_lock);
518 while (likely(!list_empty(&fput_head))) {
519 struct kiocb *req = list_kiocb(fput_head.next);
520 struct kioctx *ctx = req->ki_ctx;
521
522 list_del(&req->ki_list);
523 spin_unlock_irq(&fput_lock);
524
Davide Libenzi87c3a862009-03-18 17:04:19 -0700525 /* Complete the fput(s) */
526 if (req->ki_filp != NULL)
Al Virod7065da2010-05-26 15:13:55 -0400527 fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528
529 /* Link the iocb into the context's free list */
530 spin_lock_irq(&ctx->ctx_lock);
531 really_put_req(ctx, req);
532 spin_unlock_irq(&ctx->ctx_lock);
533
534 put_ioctx(ctx);
535 spin_lock_irq(&fput_lock);
536 }
537 spin_unlock_irq(&fput_lock);
538}
539
540/* __aio_put_req
541 * Returns true if this put was the last user of the request.
542 */
543static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
544{
Al Viro516e0cc2008-07-26 00:39:17 -0400545 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
546 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
Zach Brownd00689a2005-11-13 16:07:34 -0800548 assert_spin_locked(&ctx->ctx_lock);
549
Davide Libenzi87c3a862009-03-18 17:04:19 -0700550 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100551 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 if (likely(req->ki_users))
553 return 0;
554 list_del(&req->ki_list); /* remove from active_reqs */
555 req->ki_cancel = NULL;
556 req->ki_retry = NULL;
557
Davide Libenzi87c3a862009-03-18 17:04:19 -0700558 /*
559 * Try to optimize the aio and eventfd file* puts, by avoiding to
Al Virod7065da2010-05-26 15:13:55 -0400560 * schedule work in case it is not final fput() time. In normal cases,
Davide Libenzi87c3a862009-03-18 17:04:19 -0700561 * we would not be holding the last reference to the file*, so
562 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 */
Al Virod7065da2010-05-26 15:13:55 -0400564 if (unlikely(!fput_atomic(req->ki_filp))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 get_ioctx(ctx);
566 spin_lock(&fput_lock);
567 list_add(&req->ki_list, &fput_head);
568 spin_unlock(&fput_lock);
Tejun Heod37adaa2011-01-26 17:42:27 +0100569 schedule_work(&fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700570 } else {
571 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700573 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 return 1;
575}
576
577/* aio_put_req
578 * Returns true if this put was the last user of the kiocb,
579 * false if the request is still in use.
580 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800581int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582{
583 struct kioctx *ctx = req->ki_ctx;
584 int ret;
585 spin_lock_irq(&ctx->ctx_lock);
586 ret = __aio_put_req(ctx, req);
587 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 return ret;
589}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700590EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
Adrian Bunkd5470b52008-04-29 00:58:57 -0700592static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593{
Jens Axboeabf137d2008-12-09 08:11:22 +0100594 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700595 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100596 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597
Jens Axboeabf137d2008-12-09 08:11:22 +0100598 rcu_read_lock();
599
600 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800601 /*
602 * RCU protects us against accessing freed memory but
603 * we have to be careful not to get a reference when the
604 * reference count already dropped to 0 (ctx->dead test
605 * is unreliable because of races).
606 */
607 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700608 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 break;
610 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100611 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612
Jens Axboeabf137d2008-12-09 08:11:22 +0100613 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700614 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615}
616
617/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 * Queue up a kiocb to be retried. Assumes that the kiocb
619 * has already been marked as kicked, and places it on
620 * the retry run list for the corresponding ioctx, if it
621 * isn't already queued. Returns 1 if it actually queued
622 * the kiocb (to tell the caller to activate the work
623 * queue to process it), or 0, if it found that it was
624 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 */
626static inline int __queue_kicked_iocb(struct kiocb *iocb)
627{
628 struct kioctx *ctx = iocb->ki_ctx;
629
Zach Brownd00689a2005-11-13 16:07:34 -0800630 assert_spin_locked(&ctx->ctx_lock);
631
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 if (list_empty(&iocb->ki_run_list)) {
633 list_add_tail(&iocb->ki_run_list,
634 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 return 1;
636 }
637 return 0;
638}
639
640/* aio_run_iocb
641 * This is the core aio execution routine. It is
642 * invoked both for initial i/o submission and
643 * subsequent retries via the aio_kick_handler.
644 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200645 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 * as needed during processing.
647 *
648 * Calls the iocb retry method (already setup for the
649 * iocb on initial submission) for operation specific
650 * handling, but takes care of most of common retry
651 * execution details for a given iocb. The retry method
652 * needs to be non-blocking as far as possible, to avoid
653 * holding up other iocbs waiting to be serviced by the
654 * retry kernel thread.
655 *
656 * The trickier parts in this code have to do with
657 * ensuring that only one retry instance is in progress
658 * for a given iocb at any time. Providing that guarantee
659 * simplifies the coding of individual aio operations as
660 * it avoids various potential races.
661 */
662static ssize_t aio_run_iocb(struct kiocb *iocb)
663{
664 struct kioctx *ctx = iocb->ki_ctx;
665 ssize_t (*retry)(struct kiocb *);
666 ssize_t ret;
667
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 if (!(retry = iocb->ki_retry)) {
669 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
670 return 0;
671 }
672
673 /*
674 * We don't want the next retry iteration for this
675 * operation to start until this one has returned and
676 * updated the iocb state. However, wait_queue functions
677 * can trigger a kick_iocb from interrupt context in the
678 * meantime, indicating that data is available for the next
679 * iteration. We want to remember that and enable the
680 * next retry iteration _after_ we are through with
681 * this one.
682 *
683 * So, in order to be able to register a "kick", but
684 * prevent it from being queued now, we clear the kick
685 * flag, but make the kick code *think* that the iocb is
686 * still on the run list until we are actually done.
687 * When we are done with this iteration, we check if
688 * the iocb was kicked in the meantime and if so, queue
689 * it up afresh.
690 */
691
692 kiocbClearKicked(iocb);
693
694 /*
695 * This is so that aio_complete knows it doesn't need to
696 * pull the iocb off the run list (We can't just call
697 * INIT_LIST_HEAD because we don't want a kick_iocb to
698 * queue this on the run list yet)
699 */
700 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
701 spin_unlock_irq(&ctx->ctx_lock);
702
703 /* Quit retrying if the i/o has been cancelled */
704 if (kiocbIsCancelled(iocb)) {
705 ret = -EINTR;
706 aio_complete(iocb, ret, 0);
707 /* must not access the iocb after this */
708 goto out;
709 }
710
711 /*
712 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700713 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716
Jan Karaa0c42ba2010-09-22 13:05:03 -0700717 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
718 /*
719 * There's no easy way to restart the syscall since other AIO's
720 * may be already running. Just fail this IO with EINTR.
721 */
722 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
723 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
724 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700725 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700726 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727out:
728 spin_lock_irq(&ctx->ctx_lock);
729
730 if (-EIOCBRETRY == ret) {
731 /*
732 * OK, now that we are done with this iteration
733 * and know that there is more left to go,
734 * this is where we let go so that a subsequent
735 * "kick" can start the next iteration
736 */
737
738 /* will make __queue_kicked_iocb succeed from here on */
739 INIT_LIST_HEAD(&iocb->ki_run_list);
740 /* we must queue the next iteration ourselves, if it
741 * has already been kicked */
742 if (kiocbIsKicked(iocb)) {
743 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700744
745 /*
746 * __queue_kicked_iocb will always return 1 here, because
747 * iocb->ki_run_list is empty at this point so it should
748 * be safe to unconditionally queue the context into the
749 * work queue.
750 */
751 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 }
753 }
754 return ret;
755}
756
757/*
758 * __aio_run_iocbs:
759 * Process all pending retries queued on the ioctx
760 * run list.
761 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800762 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 */
764static int __aio_run_iocbs(struct kioctx *ctx)
765{
766 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700767 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Zach Brownd00689a2005-11-13 16:07:34 -0800769 assert_spin_locked(&ctx->ctx_lock);
770
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700771 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 while (!list_empty(&run_list)) {
773 iocb = list_entry(run_list.next, struct kiocb,
774 ki_run_list);
775 list_del(&iocb->ki_run_list);
776 /*
777 * Hold an extra reference while retrying i/o.
778 */
779 iocb->ki_users++; /* grab extra reference */
780 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800781 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 if (!list_empty(&ctx->run_list))
784 return 1;
785 return 0;
786}
787
788static void aio_queue_work(struct kioctx * ctx)
789{
790 unsigned long timeout;
791 /*
792 * if someone is waiting, get the work started right
793 * away, otherwise, use a longer delay
794 */
795 smp_mb();
796 if (waitqueue_active(&ctx->wait))
797 timeout = 1;
798 else
799 timeout = HZ/10;
800 queue_delayed_work(aio_wq, &ctx->wq, timeout);
801}
802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803/*
Jeff Moyerd3486f82011-01-12 17:01:08 -0800804 * aio_run_all_iocbs:
805 * Process all pending retries queued on the ioctx
806 * run list, and keep running them until the list
807 * stays empty.
808 * Assumes it is operating within the aio issuer's mm context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 */
810static inline void aio_run_all_iocbs(struct kioctx *ctx)
811{
812 spin_lock_irq(&ctx->ctx_lock);
813 while (__aio_run_iocbs(ctx))
814 ;
815 spin_unlock_irq(&ctx->ctx_lock);
816}
817
818/*
819 * aio_kick_handler:
820 * Work queue handler triggered to process pending
821 * retries on an ioctx. Takes on the aio issuer's
822 * mm context before running the iocbs, so that
823 * copy_xxx_user operates on the issuer's address
824 * space.
825 * Run on aiod's context.
826 */
David Howells65f27f32006-11-22 14:55:48 +0000827static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828{
David Howells65f27f32006-11-22 14:55:48 +0000829 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800831 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 int requeue;
833
834 set_fs(USER_DS);
835 use_mm(ctx->mm);
836 spin_lock_irq(&ctx->ctx_lock);
837 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800838 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800840 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 set_fs(oldfs);
842 /*
843 * we're in a worker thread already, don't use queue_delayed_work,
844 */
845 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000846 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847}
848
849
850/*
851 * Called by kick_iocb to queue the kiocb for retry
852 * and if required activate the aio work queue to process
853 * it
854 */
Zach Brown998765e2005-09-30 11:58:54 -0700855static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856{
857 struct kioctx *ctx = iocb->ki_ctx;
858 unsigned long flags;
859 int run = 0;
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700862 /* set this inside the lock so that we can't race with aio_run_iocb()
863 * testing it and putting the iocb on the run list under the lock */
864 if (!kiocbTryKick(iocb))
865 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700867 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869}
870
871/*
872 * kick_iocb:
873 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800874 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 * The retry is usually executed by aio workqueue
876 * threads (See aio_kick_handler).
877 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800878void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879{
880 /* sync iocbs are easy: they can only ever be executing from a
881 * single context. */
882 if (is_sync_kiocb(iocb)) {
883 kiocbSetKicked(iocb);
884 wake_up_process(iocb->ki_obj.tsk);
885 return;
886 }
887
Zach Brown998765e2005-09-30 11:58:54 -0700888 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889}
890EXPORT_SYMBOL(kick_iocb);
891
892/* aio_complete
893 * Called when the io request on the given iocb is complete.
894 * Returns true if this is the last user of the request. The
895 * only other user of the request can be the cancellation code.
896 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800897int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898{
899 struct kioctx *ctx = iocb->ki_ctx;
900 struct aio_ring_info *info;
901 struct aio_ring *ring;
902 struct io_event *event;
903 unsigned long flags;
904 unsigned long tail;
905 int ret;
906
Zach Brown20dcae32005-11-13 16:07:33 -0800907 /*
908 * Special case handling for sync iocbs:
909 * - events go directly into the iocb for fast handling
910 * - the sync task with the iocb in its stack holds the single iocb
911 * ref, no other paths have a way to get another ref
912 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 */
914 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800915 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800917 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800919 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 }
921
922 info = &ctx->ring_info;
923
924 /* add a completion event to the ring buffer.
925 * must be done holding ctx->ctx_lock to prevent
926 * other code from messing with the tail
927 * pointer since we might be called from irq
928 * context.
929 */
930 spin_lock_irqsave(&ctx->ctx_lock, flags);
931
932 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
933 list_del_init(&iocb->ki_run_list);
934
935 /*
936 * cancelled requests don't get events, userland was given one
937 * when the event got cancelled.
938 */
939 if (kiocbIsCancelled(iocb))
940 goto put_rq;
941
942 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
943
944 tail = info->tail;
945 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700946 if (++tail >= info->nr)
947 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948
949 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
950 event->data = iocb->ki_user_data;
951 event->res = res;
952 event->res2 = res2;
953
954 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
955 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
956 res, res2);
957
958 /* after flagging the request as done, we
959 * must never even look at it again
960 */
961 smp_wmb(); /* make event visible before updating tail */
962
963 info->tail = tail;
964 ring->tail = tail;
965
966 put_aio_ring_event(event, KM_IRQ0);
967 kunmap_atomic(ring, KM_IRQ1);
968
969 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700970
971 /*
972 * Check if the user asked us to deliver the result through an
973 * eventfd. The eventfd_signal() function is safe to be called
974 * from IRQ context.
975 */
Davide Libenzi87c3a862009-03-18 17:04:19 -0700976 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700977 eventfd_signal(iocb->ki_eventfd, 1);
978
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979put_rq:
980 /* everything turned out well, dispose of the aiocb. */
981 ret = __aio_put_req(ctx, iocb);
982
Quentin Barnes6cb2a212008-03-19 17:00:39 -0700983 /*
984 * We have to order our ring_info tail store above and test
985 * of the wait list below outside the wait lock. This is
986 * like in wake_up_bit() where clearing a bit has to be
987 * ordered with the unlocked test.
988 */
989 smp_mb();
990
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 if (waitqueue_active(&ctx->wait))
992 wake_up(&ctx->wait);
993
Ken Chendee11c22007-02-03 01:13:45 -0800994 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 return ret;
996}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700997EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998
999/* aio_read_evt
1000 * Pull an event off of the ioctx's event ring. Returns the number of
1001 * events fetched (0 or 1 ;-)
1002 * FIXME: make this use cmpxchg.
1003 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1004 */
1005static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1006{
1007 struct aio_ring_info *info = &ioctx->ring_info;
1008 struct aio_ring *ring;
1009 unsigned long head;
1010 int ret = 0;
1011
1012 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1013 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1014 (unsigned long)ring->head, (unsigned long)ring->tail,
1015 (unsigned long)ring->nr);
1016
1017 if (ring->head == ring->tail)
1018 goto out;
1019
1020 spin_lock(&info->ring_lock);
1021
1022 head = ring->head % info->nr;
1023 if (head != ring->tail) {
1024 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1025 *ent = *evp;
1026 head = (head + 1) % info->nr;
1027 smp_mb(); /* finish reading the event before updatng the head */
1028 ring->head = head;
1029 ret = 1;
1030 put_aio_ring_event(evp, KM_USER1);
1031 }
1032 spin_unlock(&info->ring_lock);
1033
1034out:
1035 kunmap_atomic(ring, KM_USER0);
1036 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1037 (unsigned long)ring->head, (unsigned long)ring->tail);
1038 return ret;
1039}
1040
1041struct aio_timeout {
1042 struct timer_list timer;
1043 int timed_out;
1044 struct task_struct *p;
1045};
1046
1047static void timeout_func(unsigned long data)
1048{
1049 struct aio_timeout *to = (struct aio_timeout *)data;
1050
1051 to->timed_out = 1;
1052 wake_up_process(to->p);
1053}
1054
1055static inline void init_timeout(struct aio_timeout *to)
1056{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001057 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 to->timed_out = 0;
1059 to->p = current;
1060}
1061
1062static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1063 const struct timespec *ts)
1064{
1065 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1066 if (time_after(to->timer.expires, jiffies))
1067 add_timer(&to->timer);
1068 else
1069 to->timed_out = 1;
1070}
1071
1072static inline void clear_timeout(struct aio_timeout *to)
1073{
1074 del_singleshot_timer_sync(&to->timer);
1075}
1076
1077static int read_events(struct kioctx *ctx,
1078 long min_nr, long nr,
1079 struct io_event __user *event,
1080 struct timespec __user *timeout)
1081{
1082 long start_jiffies = jiffies;
1083 struct task_struct *tsk = current;
1084 DECLARE_WAITQUEUE(wait, tsk);
1085 int ret;
1086 int i = 0;
1087 struct io_event ent;
1088 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 int retry = 0;
1090
1091 /* needed to zero any padding within an entry (there shouldn't be
1092 * any, but C is fun!
1093 */
1094 memset(&ent, 0, sizeof(ent));
1095retry:
1096 ret = 0;
1097 while (likely(i < nr)) {
1098 ret = aio_read_evt(ctx, &ent);
1099 if (unlikely(ret <= 0))
1100 break;
1101
1102 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1103 ent.data, ent.obj, ent.res, ent.res2);
1104
1105 /* Could we split the check in two? */
1106 ret = -EFAULT;
1107 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1108 dprintk("aio: lost an event due to EFAULT.\n");
1109 break;
1110 }
1111 ret = 0;
1112
1113 /* Good, event copied to userland, update counts. */
1114 event ++;
1115 i ++;
1116 }
1117
1118 if (min_nr <= i)
1119 return i;
1120 if (ret)
1121 return ret;
1122
1123 /* End fast path */
1124
1125 /* racey check, but it gets redone */
1126 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1127 retry = 1;
1128 aio_run_all_iocbs(ctx);
1129 goto retry;
1130 }
1131
1132 init_timeout(&to);
1133 if (timeout) {
1134 struct timespec ts;
1135 ret = -EFAULT;
1136 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1137 goto out;
1138
1139 set_timeout(start_jiffies, &to, &ts);
1140 }
1141
1142 while (likely(i < nr)) {
1143 add_wait_queue_exclusive(&ctx->wait, &wait);
1144 do {
1145 set_task_state(tsk, TASK_INTERRUPTIBLE);
1146 ret = aio_read_evt(ctx, &ent);
1147 if (ret)
1148 break;
1149 if (min_nr <= i)
1150 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001151 if (unlikely(ctx->dead)) {
1152 ret = -EINVAL;
1153 break;
1154 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 if (to.timed_out) /* Only check after read evt */
1156 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001157 /* Try to only show up in io wait if there are ops
1158 * in flight */
1159 if (ctx->reqs_active)
1160 io_schedule();
1161 else
1162 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 if (signal_pending(tsk)) {
1164 ret = -EINTR;
1165 break;
1166 }
1167 /*ret = aio_read_evt(ctx, &ent);*/
1168 } while (1) ;
1169
1170 set_task_state(tsk, TASK_RUNNING);
1171 remove_wait_queue(&ctx->wait, &wait);
1172
1173 if (unlikely(ret <= 0))
1174 break;
1175
1176 ret = -EFAULT;
1177 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1178 dprintk("aio: lost an event due to EFAULT.\n");
1179 break;
1180 }
1181
1182 /* Good, event copied to userland, update counts. */
1183 event ++;
1184 i ++;
1185 }
1186
1187 if (timeout)
1188 clear_timeout(&to);
1189out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001190 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 return i ? i : ret;
1192}
1193
1194/* Take an ioctx and remove it from the list of ioctx's. Protects
1195 * against races with itself via ->dead.
1196 */
1197static void io_destroy(struct kioctx *ioctx)
1198{
1199 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 int was_dead;
1201
1202 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001203 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 was_dead = ioctx->dead;
1205 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001206 hlist_del_rcu(&ioctx->list);
1207 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208
1209 dprintk("aio_release(%p)\n", ioctx);
1210 if (likely(!was_dead))
1211 put_ioctx(ioctx); /* twice for the list */
1212
1213 aio_cancel_all(ioctx);
1214 wait_for_all_aios(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001215
1216 /*
1217 * Wake up any waiters. The setting of ctx->dead must be seen
1218 * by other CPUs at this point. Right now, we rely on the
1219 * locking done by the above calls to ensure this consistency.
1220 */
Roland Dreiere91f90b2011-03-22 16:35:10 -07001221 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 put_ioctx(ioctx); /* once for the lookup */
1223}
1224
1225/* sys_io_setup:
1226 * Create an aio_context capable of receiving at least nr_events.
1227 * ctxp must not point to an aio_context that already exists, and
1228 * must be initialized to 0 prior to the call. On successful
1229 * creation of the aio_context, *ctxp is filled in with the resulting
1230 * handle. May fail with -EINVAL if *ctxp is not initialized,
1231 * if the specified nr_events exceeds internal limits. May fail
1232 * with -EAGAIN if the specified nr_events exceeds the user's limit
1233 * of available events. May fail with -ENOMEM if insufficient kernel
1234 * resources are available. May fail with -EFAULT if an invalid
1235 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1236 * implemented.
1237 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001238SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239{
1240 struct kioctx *ioctx = NULL;
1241 unsigned long ctx;
1242 long ret;
1243
1244 ret = get_user(ctx, ctxp);
1245 if (unlikely(ret))
1246 goto out;
1247
1248 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001249 if (unlikely(ctx || nr_events == 0)) {
1250 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1251 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 goto out;
1253 }
1254
1255 ioctx = ioctx_alloc(nr_events);
1256 ret = PTR_ERR(ioctx);
1257 if (!IS_ERR(ioctx)) {
1258 ret = put_user(ioctx->user_id, ctxp);
1259 if (!ret)
1260 return 0;
1261
1262 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1263 io_destroy(ioctx);
1264 }
1265
1266out:
1267 return ret;
1268}
1269
1270/* sys_io_destroy:
1271 * Destroy the aio_context specified. May cancel any outstanding
1272 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001273 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 * is invalid.
1275 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001276SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277{
1278 struct kioctx *ioctx = lookup_ioctx(ctx);
1279 if (likely(NULL != ioctx)) {
1280 io_destroy(ioctx);
1281 return 0;
1282 }
1283 pr_debug("EINVAL: io_destroy: invalid context id\n");
1284 return -EINVAL;
1285}
1286
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001287static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1288{
1289 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1290
1291 BUG_ON(ret <= 0);
1292
1293 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1294 ssize_t this = min((ssize_t)iov->iov_len, ret);
1295 iov->iov_base += this;
1296 iov->iov_len -= this;
1297 iocb->ki_left -= this;
1298 ret -= this;
1299 if (iov->iov_len == 0) {
1300 iocb->ki_cur_seg++;
1301 iov++;
1302 }
1303 }
1304
1305 /* the caller should not have done more io than what fit in
1306 * the remaining iovecs */
1307 BUG_ON(ret > 0 && iocb->ki_left == 0);
1308}
1309
1310static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311{
1312 struct file *file = iocb->ki_filp;
1313 struct address_space *mapping = file->f_mapping;
1314 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001315 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1316 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001318 unsigned short opcode;
1319
1320 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1321 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1322 rw_op = file->f_op->aio_read;
1323 opcode = IOCB_CMD_PREADV;
1324 } else {
1325 rw_op = file->f_op->aio_write;
1326 opcode = IOCB_CMD_PWRITEV;
1327 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328
Rusty Russellc2ec6682008-02-08 04:20:15 -08001329 /* This matches the pread()/pwrite() logic */
1330 if (iocb->ki_pos < 0)
1331 return -EINVAL;
1332
Zach Brown897f15f2005-09-30 11:58:55 -07001333 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001334 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1335 iocb->ki_nr_segs - iocb->ki_cur_seg,
1336 iocb->ki_pos);
1337 if (ret > 0)
1338 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001339
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001340 /* retry all partial writes. retry partial reads as long as its a
1341 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001342 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001343 (opcode == IOCB_CMD_PWRITEV ||
1344 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
1346 /* This means we must have transferred all that we could */
1347 /* No need to retry anymore */
1348 if ((ret == 0) || (iocb->ki_left == 0))
1349 ret = iocb->ki_nbytes - iocb->ki_left;
1350
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001351 /* If we managed to write some out we return that, rather than
1352 * the eventual error. */
1353 if (opcode == IOCB_CMD_PWRITEV
1354 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1355 && iocb->ki_nbytes - iocb->ki_left)
1356 ret = iocb->ki_nbytes - iocb->ki_left;
1357
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 return ret;
1359}
1360
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361static ssize_t aio_fdsync(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, 1);
1368 return ret;
1369}
1370
1371static ssize_t aio_fsync(struct kiocb *iocb)
1372{
1373 struct file *file = iocb->ki_filp;
1374 ssize_t ret = -EINVAL;
1375
1376 if (file->f_op->aio_fsync)
1377 ret = file->f_op->aio_fsync(iocb, 0);
1378 return ret;
1379}
1380
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001381static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001382{
1383 ssize_t ret;
1384
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001385#ifdef CONFIG_COMPAT
1386 if (compat)
1387 ret = compat_rw_copy_check_uvector(type,
1388 (struct compat_iovec __user *)kiocb->ki_buf,
1389 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001390 &kiocb->ki_iovec, 1);
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001391 else
1392#endif
1393 ret = rw_copy_check_uvector(type,
1394 (struct iovec __user *)kiocb->ki_buf,
1395 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001396 &kiocb->ki_iovec, 1);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001397 if (ret < 0)
1398 goto out;
1399
1400 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1401 kiocb->ki_cur_seg = 0;
1402 /* ki_nbytes/left now reflect bytes instead of segs */
1403 kiocb->ki_nbytes = ret;
1404 kiocb->ki_left = ret;
1405
1406 ret = 0;
1407out:
1408 return ret;
1409}
1410
1411static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1412{
1413 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1414 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1415 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1416 kiocb->ki_nr_segs = 1;
1417 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001418 return 0;
1419}
1420
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421/*
1422 * aio_setup_iocb:
1423 * Performs the initial checks and aio retry method
1424 * setup for the kiocb at the time of io submission.
1425 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001426static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427{
1428 struct file *file = kiocb->ki_filp;
1429 ssize_t ret = 0;
1430
1431 switch (kiocb->ki_opcode) {
1432 case IOCB_CMD_PREAD:
1433 ret = -EBADF;
1434 if (unlikely(!(file->f_mode & FMODE_READ)))
1435 break;
1436 ret = -EFAULT;
1437 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1438 kiocb->ki_left)))
1439 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001440 ret = security_file_permission(file, MAY_READ);
1441 if (unlikely(ret))
1442 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001443 ret = aio_setup_single_vector(kiocb);
1444 if (ret)
1445 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 ret = -EINVAL;
1447 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001448 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 break;
1450 case IOCB_CMD_PWRITE:
1451 ret = -EBADF;
1452 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1453 break;
1454 ret = -EFAULT;
1455 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1456 kiocb->ki_left)))
1457 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001458 ret = security_file_permission(file, MAY_WRITE);
1459 if (unlikely(ret))
1460 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001461 ret = aio_setup_single_vector(kiocb);
1462 if (ret)
1463 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 ret = -EINVAL;
1465 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001466 kiocb->ki_retry = aio_rw_vect_retry;
1467 break;
1468 case IOCB_CMD_PREADV:
1469 ret = -EBADF;
1470 if (unlikely(!(file->f_mode & FMODE_READ)))
1471 break;
1472 ret = security_file_permission(file, MAY_READ);
1473 if (unlikely(ret))
1474 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001475 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001476 if (ret)
1477 break;
1478 ret = -EINVAL;
1479 if (file->f_op->aio_read)
1480 kiocb->ki_retry = aio_rw_vect_retry;
1481 break;
1482 case IOCB_CMD_PWRITEV:
1483 ret = -EBADF;
1484 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1485 break;
1486 ret = security_file_permission(file, MAY_WRITE);
1487 if (unlikely(ret))
1488 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001489 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001490 if (ret)
1491 break;
1492 ret = -EINVAL;
1493 if (file->f_op->aio_write)
1494 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 break;
1496 case IOCB_CMD_FDSYNC:
1497 ret = -EINVAL;
1498 if (file->f_op->aio_fsync)
1499 kiocb->ki_retry = aio_fdsync;
1500 break;
1501 case IOCB_CMD_FSYNC:
1502 ret = -EINVAL;
1503 if (file->f_op->aio_fsync)
1504 kiocb->ki_retry = aio_fsync;
1505 break;
1506 default:
1507 dprintk("EINVAL: io_submit: no operation provided\n");
1508 ret = -EINVAL;
1509 }
1510
1511 if (!kiocb->ki_retry)
1512 return ret;
1513
1514 return 0;
1515}
1516
Adrian Bunkd5470b52008-04-29 00:58:57 -07001517static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jens Axboecf159002011-03-02 20:12:18 -05001518 struct iocb *iocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519{
1520 struct kiocb *req;
1521 struct file *file;
1522 ssize_t ret;
1523
1524 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001525 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 pr_debug("EINVAL: io_submit: reserve field set\n");
1527 return -EINVAL;
1528 }
1529
1530 /* prevent overflows */
1531 if (unlikely(
1532 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1533 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1534 ((ssize_t)iocb->aio_nbytes < 0)
1535 )) {
1536 pr_debug("EINVAL: io_submit: overflow check\n");
1537 return -EINVAL;
1538 }
1539
1540 file = fget(iocb->aio_fildes);
1541 if (unlikely(!file))
1542 return -EBADF;
1543
1544 req = aio_get_req(ctx); /* returns with 2 references to req */
1545 if (unlikely(!req)) {
1546 fput(file);
1547 return -EAGAIN;
1548 }
Yan Zheng87e28312007-10-08 12:16:20 -07001549 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001550 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1551 /*
1552 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1553 * instance of the file* now. The file descriptor must be
1554 * an eventfd() fd, and will be signaled for each completed
1555 * event using the eventfd_signal() function.
1556 */
Davide Libenzi13389012009-06-30 11:41:11 -07001557 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001558 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001559 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001560 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001561 goto out_put_req;
1562 }
1563 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564
Ken Chen212079c2005-05-01 08:59:15 -07001565 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 if (unlikely(ret)) {
1567 dprintk("EFAULT: aio_key\n");
1568 goto out_put_req;
1569 }
1570
1571 req->ki_obj.user = user_iocb;
1572 req->ki_user_data = iocb->aio_data;
1573 req->ki_pos = iocb->aio_offset;
1574
1575 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1576 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1577 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001578
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001579 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580
1581 if (ret)
1582 goto out_put_req;
1583
1584 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001585 /*
1586 * We could have raced with io_destroy() and are currently holding a
1587 * reference to ctx which should be destroyed. We cannot submit IO
1588 * since ctx gets freed as soon as io_submit() puts its reference. The
1589 * check here is reliable: io_destroy() sets ctx->dead before waiting
1590 * for outstanding IO and the barrier between these two is realized by
1591 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1592 * increment ctx->reqs_active before checking for ctx->dead and the
1593 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1594 * don't see ctx->dead set here, io_destroy() waits for our IO to
1595 * finish.
1596 */
1597 if (ctx->dead) {
1598 spin_unlock_irq(&ctx->ctx_lock);
1599 ret = -EINVAL;
1600 goto out_put_req;
1601 }
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001602 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001603 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001604 /* drain the run list */
1605 while (__aio_run_iocbs(ctx))
1606 ;
1607 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001609
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 aio_put_req(req); /* drop extra ref to req */
1611 return 0;
1612
1613out_put_req:
1614 aio_put_req(req); /* drop extra ref to req */
1615 aio_put_req(req); /* drop i/o ref to req */
1616 return ret;
1617}
1618
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001619long do_io_submit(aio_context_t ctx_id, long nr,
1620 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001621{
1622 struct kioctx *ctx;
1623 long ret = 0;
1624 int i;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001625 struct blk_plug plug;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626
1627 if (unlikely(nr < 0))
1628 return -EINVAL;
1629
Jeff Moyer75e1c702010-09-10 14:16:00 -07001630 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1631 nr = LONG_MAX/sizeof(*iocbpp);
1632
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1634 return -EFAULT;
1635
1636 ctx = lookup_ioctx(ctx_id);
1637 if (unlikely(!ctx)) {
1638 pr_debug("EINVAL: io_submit: invalid context id\n");
1639 return -EINVAL;
1640 }
1641
Shaohua Li9f5b9422010-07-01 07:55:01 +02001642 blk_start_plug(&plug);
1643
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 /*
1645 * AKPM: should this return a partial result if some of the IOs were
1646 * successfully submitted?
1647 */
1648 for (i=0; i<nr; i++) {
1649 struct iocb __user *user_iocb;
1650 struct iocb tmp;
1651
1652 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1653 ret = -EFAULT;
1654 break;
1655 }
1656
1657 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1658 ret = -EFAULT;
1659 break;
1660 }
1661
Jens Axboecf159002011-03-02 20:12:18 -05001662 ret = io_submit_one(ctx, user_iocb, &tmp, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 if (ret)
1664 break;
1665 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001666 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001667
1668 put_ioctx(ctx);
1669 return i ? i : ret;
1670}
1671
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001672/* sys_io_submit:
1673 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1674 * the number of iocbs queued. May return -EINVAL if the aio_context
1675 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1676 * *iocbpp[0] is not properly initialized, if the operation specified
1677 * is invalid for the file descriptor in the iocb. May fail with
1678 * -EFAULT if any of the data structures point to invalid data. May
1679 * fail with -EBADF if the file descriptor specified in the first
1680 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1681 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1682 * fail with -ENOSYS if not implemented.
1683 */
1684SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1685 struct iocb __user * __user *, iocbpp)
1686{
1687 return do_io_submit(ctx_id, nr, iocbpp, 0);
1688}
1689
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690/* lookup_kiocb
1691 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001693static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1694 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695{
1696 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001697
1698 assert_spin_locked(&ctx->ctx_lock);
1699
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 /* TODO: use a hash or array, this sucks. */
1701 list_for_each(pos, &ctx->active_reqs) {
1702 struct kiocb *kiocb = list_kiocb(pos);
1703 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1704 return kiocb;
1705 }
1706 return NULL;
1707}
1708
1709/* sys_io_cancel:
1710 * Attempts to cancel an iocb previously passed to io_submit. If
1711 * the operation is successfully cancelled, the resulting event is
1712 * copied into the memory pointed to by result without being placed
1713 * into the completion queue and 0 is returned. May fail with
1714 * -EFAULT if any of the data structures pointed to are invalid.
1715 * May fail with -EINVAL if aio_context specified by ctx_id is
1716 * invalid. May fail with -EAGAIN if the iocb specified was not
1717 * cancelled. Will fail with -ENOSYS if not implemented.
1718 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001719SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1720 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721{
1722 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1723 struct kioctx *ctx;
1724 struct kiocb *kiocb;
1725 u32 key;
1726 int ret;
1727
1728 ret = get_user(key, &iocb->aio_key);
1729 if (unlikely(ret))
1730 return -EFAULT;
1731
1732 ctx = lookup_ioctx(ctx_id);
1733 if (unlikely(!ctx))
1734 return -EINVAL;
1735
1736 spin_lock_irq(&ctx->ctx_lock);
1737 ret = -EAGAIN;
1738 kiocb = lookup_kiocb(ctx, iocb, key);
1739 if (kiocb && kiocb->ki_cancel) {
1740 cancel = kiocb->ki_cancel;
1741 kiocb->ki_users ++;
1742 kiocbSetCancelled(kiocb);
1743 } else
1744 cancel = NULL;
1745 spin_unlock_irq(&ctx->ctx_lock);
1746
1747 if (NULL != cancel) {
1748 struct io_event tmp;
1749 pr_debug("calling cancel\n");
1750 memset(&tmp, 0, sizeof(tmp));
1751 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1752 tmp.data = kiocb->ki_user_data;
1753 ret = cancel(kiocb, &tmp);
1754 if (!ret) {
1755 /* Cancellation succeeded -- copy the result
1756 * into the user's buffer.
1757 */
1758 if (copy_to_user(result, &tmp, sizeof(tmp)))
1759 ret = -EFAULT;
1760 }
1761 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001762 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763
1764 put_ioctx(ctx);
1765
1766 return ret;
1767}
1768
1769/* io_getevents:
1770 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001771 * the completion queue for the aio_context specified by ctx_id. If
1772 * it succeeds, the number of read events is returned. May fail with
1773 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1774 * out of range, if timeout is out of range. May fail with -EFAULT
1775 * if any of the memory specified is invalid. May return 0 or
1776 * < min_nr if the timeout specified by timeout has elapsed
1777 * before sufficient events are available, where timeout == NULL
1778 * specifies an infinite timeout. Note that the timeout pointed to by
1779 * timeout is relative and will be updated if not NULL and the
1780 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001782SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1783 long, min_nr,
1784 long, nr,
1785 struct io_event __user *, events,
1786 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787{
1788 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1789 long ret = -EINVAL;
1790
1791 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001792 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793 ret = read_events(ioctx, min_nr, nr, events, timeout);
1794 put_ioctx(ioctx);
1795 }
1796
Roland McGrath598af052008-04-10 15:38:45 -07001797 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 return ret;
1799}