blob: 1cf12b3dd83a0654d7c0629786d8ab7fd4388a23 [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>
37#include <linux/mempool.h>
38#include <linux/hash.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40#include <asm/kmap_types.h>
41#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43#if DEBUG > 1
44#define dprintk printk
45#else
46#define dprintk(x...) do { ; } while (0)
47#endif
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/*------ sysctl variables----*/
Zach Brownd55b5fd2005-11-07 00:59:31 -080050static DEFINE_SPINLOCK(aio_nr_lock);
51unsigned long aio_nr; /* current system wide number of aio requests */
52unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
Linus Torvalds1da177e2005-04-16 15:20:36 -070053/*----end sysctl variables---*/
54
Christoph Lametere18b8902006-12-06 20:33:20 -080055static struct kmem_cache *kiocb_cachep;
56static struct kmem_cache *kioctx_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
58static struct workqueue_struct *aio_wq;
59
60/* Used for rare fput completion. */
David Howells65f27f32006-11-22 14:55:48 +000061static void aio_fput_routine(struct work_struct *);
62static DECLARE_WORK(fput_work, aio_fput_routine);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
64static DEFINE_SPINLOCK(fput_lock);
Adrian Bunk25ee7e32005-04-25 08:18:14 -070065static LIST_HEAD(fput_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
Jeff Moyercfb1e332009-10-02 18:57:36 -040067#define AIO_BATCH_HASH_BITS 3 /* allocated on-stack, so don't go crazy */
68#define AIO_BATCH_HASH_SIZE (1 << AIO_BATCH_HASH_BITS)
69struct aio_batch_entry {
70 struct hlist_node list;
71 struct address_space *mapping;
72};
73mempool_t *abe_pool;
74
David Howells65f27f32006-11-22 14:55:48 +000075static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070076static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
78/* aio_setup
79 * Creates the slab caches used by the aio routines, panic on
80 * failure as this is done early during the boot sequence.
81 */
82static int __init aio_setup(void)
83{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070084 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
85 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87 aio_wq = create_workqueue("aio");
Jeff Moyercfb1e332009-10-02 18:57:36 -040088 abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry));
89 BUG_ON(!abe_pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
92
93 return 0;
94}
H Hartley Sweeten385773e2009-09-22 16:43:53 -070095__initcall(aio_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97static void aio_free_ring(struct kioctx *ctx)
98{
99 struct aio_ring_info *info = &ctx->ring_info;
100 long i;
101
102 for (i=0; i<info->nr_pages; i++)
103 put_page(info->ring_pages[i]);
104
105 if (info->mmap_size) {
106 down_write(&ctx->mm->mmap_sem);
107 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
108 up_write(&ctx->mm->mmap_sem);
109 }
110
111 if (info->ring_pages && info->ring_pages != info->internal_pages)
112 kfree(info->ring_pages);
113 info->ring_pages = NULL;
114 info->nr = 0;
115}
116
117static int aio_setup_ring(struct kioctx *ctx)
118{
119 struct aio_ring *ring;
120 struct aio_ring_info *info = &ctx->ring_info;
121 unsigned nr_events = ctx->max_reqs;
122 unsigned long size;
123 int nr_pages;
124
125 /* Compensate for the ring buffer's head/tail overlap entry */
126 nr_events += 2; /* 1 is required, 2 for good luck */
127
128 size = sizeof(struct aio_ring);
129 size += sizeof(struct io_event) * nr_events;
130 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
131
132 if (nr_pages < 0)
133 return -EINVAL;
134
135 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
136
137 info->nr = 0;
138 info->ring_pages = info->internal_pages;
139 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800140 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 if (!info->ring_pages)
142 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 }
144
145 info->mmap_size = nr_pages * PAGE_SIZE;
146 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
147 down_write(&ctx->mm->mmap_sem);
148 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
Robert P. J. Daye10a4432007-02-10 01:42:56 -0800149 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 0);
151 if (IS_ERR((void *)info->mmap_base)) {
152 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 info->mmap_size = 0;
154 aio_free_ring(ctx);
155 return -EAGAIN;
156 }
157
158 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
159 info->nr_pages = get_user_pages(current, ctx->mm,
160 info->mmap_base, nr_pages,
161 1, 0, info->ring_pages, NULL);
162 up_write(&ctx->mm->mmap_sem);
163
164 if (unlikely(info->nr_pages != nr_pages)) {
165 aio_free_ring(ctx);
166 return -EAGAIN;
167 }
168
169 ctx->user_id = info->mmap_base;
170
171 info->nr = nr_events; /* trusted copy */
172
173 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
174 ring->nr = nr_events; /* user copy */
175 ring->id = ctx->user_id;
176 ring->head = ring->tail = 0;
177 ring->magic = AIO_RING_MAGIC;
178 ring->compat_features = AIO_RING_COMPAT_FEATURES;
179 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
180 ring->header_length = sizeof(struct aio_ring);
181 kunmap_atomic(ring, KM_USER0);
182
183 return 0;
184}
185
186
187/* aio_ring_event: returns a pointer to the event at the given index from
188 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
189 */
190#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
191#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
192#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
193
194#define aio_ring_event(info, nr, km) ({ \
195 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
196 struct io_event *__event; \
197 __event = kmap_atomic( \
198 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
199 __event += pos % AIO_EVENTS_PER_PAGE; \
200 __event; \
201})
202
203#define put_aio_ring_event(event, km) do { \
204 struct io_event *__event = (event); \
205 (void)__event; \
206 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
207} while(0)
208
Jens Axboeabf137d2008-12-09 08:11:22 +0100209static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700210{
Jens Axboeabf137d2008-12-09 08:11:22 +0100211 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700212 unsigned nr_events = ctx->max_reqs;
213
Adrian Bunkd5470b52008-04-29 00:58:57 -0700214 kmem_cache_free(kioctx_cachep, ctx);
215
216 if (nr_events) {
217 spin_lock(&aio_nr_lock);
218 BUG_ON(aio_nr - nr_events > aio_nr);
219 aio_nr -= nr_events;
220 spin_unlock(&aio_nr_lock);
221 }
222}
223
Jens Axboeabf137d2008-12-09 08:11:22 +0100224/* __put_ioctx
225 * Called when the last user of an aio context has gone away,
226 * and the struct needs to be freed.
227 */
228static void __put_ioctx(struct kioctx *ctx)
229{
230 BUG_ON(ctx->reqs_active);
231
232 cancel_delayed_work(&ctx->wq);
233 cancel_work_sync(&ctx->wq.work);
234 aio_free_ring(ctx);
235 mmdrop(ctx->mm);
236 ctx->mm = NULL;
237 pr_debug("__put_ioctx: freeing %p\n", ctx);
238 call_rcu(&ctx->rcu_head, ctx_rcu_free);
239}
240
Adrian Bunkd5470b52008-04-29 00:58:57 -0700241#define get_ioctx(kioctx) do { \
242 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
243 atomic_inc(&(kioctx)->users); \
244} while (0)
245#define put_ioctx(kioctx) do { \
246 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
247 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
248 __put_ioctx(kioctx); \
249} while (0)
250
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251/* ioctx_alloc
252 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
253 */
254static struct kioctx *ioctx_alloc(unsigned nr_events)
255{
256 struct mm_struct *mm;
257 struct kioctx *ctx;
Jens Axboeabf137d2008-12-09 08:11:22 +0100258 int did_sync = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260 /* Prevent overflows */
261 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
262 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
263 pr_debug("ENOMEM: nr_events too high\n");
264 return ERR_PTR(-EINVAL);
265 }
266
Zach Brownd55b5fd2005-11-07 00:59:31 -0800267 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 return ERR_PTR(-EAGAIN);
269
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800270 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 if (!ctx)
272 return ERR_PTR(-ENOMEM);
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 ctx->max_reqs = nr_events;
275 mm = ctx->mm = current->mm;
276 atomic_inc(&mm->mm_count);
277
278 atomic_set(&ctx->users, 1);
279 spin_lock_init(&ctx->ctx_lock);
280 spin_lock_init(&ctx->ring_info.ring_lock);
281 init_waitqueue_head(&ctx->wait);
282
283 INIT_LIST_HEAD(&ctx->active_reqs);
284 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000285 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
287 if (aio_setup_ring(ctx) < 0)
288 goto out_freectx;
289
290 /* limit the number of system wide aios */
Jens Axboeabf137d2008-12-09 08:11:22 +0100291 do {
292 spin_lock_bh(&aio_nr_lock);
293 if (aio_nr + nr_events > aio_max_nr ||
294 aio_nr + nr_events < aio_nr)
295 ctx->max_reqs = 0;
296 else
297 aio_nr += ctx->max_reqs;
298 spin_unlock_bh(&aio_nr_lock);
299 if (ctx->max_reqs || did_sync)
300 break;
301
302 /* wait for rcu callbacks to have completed before giving up */
303 synchronize_rcu();
304 did_sync = 1;
305 ctx->max_reqs = nr_events;
306 } while (1);
307
Zach Brownd55b5fd2005-11-07 00:59:31 -0800308 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 goto out_cleanup;
310
Jeff Moyer39fa0032008-04-29 01:03:48 -0700311 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100312 spin_lock(&mm->ioctx_lock);
313 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
314 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
317 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
318 return ctx;
319
320out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 __put_ioctx(ctx);
322 return ERR_PTR(-EAGAIN);
323
324out_freectx:
325 mmdrop(mm);
326 kmem_cache_free(kioctx_cachep, ctx);
327 ctx = ERR_PTR(-ENOMEM);
328
329 dprintk("aio: error allocating ioctx %p\n", ctx);
330 return ctx;
331}
332
333/* aio_cancel_all
334 * Cancels all outstanding aio requests on an aio context. Used
335 * when the processes owning a context have all exited to encourage
336 * the rapid destruction of the kioctx.
337 */
338static void aio_cancel_all(struct kioctx *ctx)
339{
340 int (*cancel)(struct kiocb *, struct io_event *);
341 struct io_event res;
342 spin_lock_irq(&ctx->ctx_lock);
343 ctx->dead = 1;
344 while (!list_empty(&ctx->active_reqs)) {
345 struct list_head *pos = ctx->active_reqs.next;
346 struct kiocb *iocb = list_kiocb(pos);
347 list_del_init(&iocb->ki_list);
348 cancel = iocb->ki_cancel;
349 kiocbSetCancelled(iocb);
350 if (cancel) {
351 iocb->ki_users++;
352 spin_unlock_irq(&ctx->ctx_lock);
353 cancel(iocb, &res);
354 spin_lock_irq(&ctx->ctx_lock);
355 }
356 }
357 spin_unlock_irq(&ctx->ctx_lock);
358}
359
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700360static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361{
362 struct task_struct *tsk = current;
363 DECLARE_WAITQUEUE(wait, tsk);
364
Ken Chendee11c22007-02-03 01:13:45 -0800365 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800367 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
369 add_wait_queue(&ctx->wait, &wait);
370 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
371 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800372 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700373 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800375 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 }
377 __set_task_state(tsk, TASK_RUNNING);
378 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800379
380out:
381 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382}
383
384/* wait_on_sync_kiocb:
385 * Waits on the given sync kiocb to complete.
386 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800387ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388{
389 while (iocb->ki_users) {
390 set_current_state(TASK_UNINTERRUPTIBLE);
391 if (!iocb->ki_users)
392 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700393 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 }
395 __set_current_state(TASK_RUNNING);
396 return iocb->ki_user_data;
397}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700398EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
400/* exit_aio: called when the last user of mm goes away. At this point,
401 * there is no way for any new requests to be submited or any of the
402 * io_* syscalls to be called on the context. However, there may be
403 * outstanding requests which hold references to the context; as they
404 * go away, they will call put_ioctx and release any pinned memory
405 * associated with the request (held via struct page * references).
406 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800407void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408{
Jens Axboeabf137d2008-12-09 08:11:22 +0100409 struct kioctx *ctx;
410
411 while (!hlist_empty(&mm->ioctx_list)) {
412 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
413 hlist_del_rcu(&ctx->list);
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 aio_cancel_all(ctx);
416
417 wait_for_all_aios(ctx);
418 /*
Andrew Mortona9df62c2007-05-09 02:33:54 -0700419 * Ensure we don't leave the ctx on the aio_wq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 */
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700421 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
423 if (1 != atomic_read(&ctx->users))
424 printk(KERN_DEBUG
425 "exit_aio:ioctx still alive: %d %d %d\n",
426 atomic_read(&ctx->users), ctx->dead,
427 ctx->reqs_active);
428 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 }
430}
431
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432/* aio_get_req
433 * Allocate a slot for an aio request. Increments the users count
434 * of the kioctx so that the kioctx stays around until all requests are
435 * complete. Returns NULL if no requests are free.
436 *
437 * Returns with kiocb->users set to 2. The io submit code path holds
438 * an extra reference while submitting the i/o.
439 * This prevents races between the aio code path referencing the
440 * req (after submitting it) and aio_complete() freeing the req.
441 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800442static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443{
444 struct kiocb *req = NULL;
445 struct aio_ring *ring;
446 int okay = 0;
447
448 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
449 if (unlikely(!req))
450 return NULL;
451
Zach Brown4faa5282005-10-17 16:43:33 -0700452 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 req->ki_users = 2;
454 req->ki_key = 0;
455 req->ki_ctx = ctx;
456 req->ki_cancel = NULL;
457 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 req->ki_dtor = NULL;
459 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700460 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700462 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463
464 /* Check if the completion queue has enough free space to
465 * accept an event from this io.
466 */
467 spin_lock_irq(&ctx->ctx_lock);
468 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
469 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
470 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 ctx->reqs_active++;
472 okay = 1;
473 }
474 kunmap_atomic(ring, KM_USER0);
475 spin_unlock_irq(&ctx->ctx_lock);
476
477 if (!okay) {
478 kmem_cache_free(kiocb_cachep, req);
479 req = NULL;
480 }
481
482 return req;
483}
484
485static inline struct kiocb *aio_get_req(struct kioctx *ctx)
486{
487 struct kiocb *req;
488 /* Handle a potential starvation case -- should be exceedingly rare as
489 * requests will be stuck on fput_head only if the aio_fput_routine is
490 * delayed and the requests were the last user of the struct file.
491 */
492 req = __aio_get_req(ctx);
493 if (unlikely(NULL == req)) {
494 aio_fput_routine(NULL);
495 req = __aio_get_req(ctx);
496 }
497 return req;
498}
499
500static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
501{
Zach Brownd00689a2005-11-13 16:07:34 -0800502 assert_spin_locked(&ctx->ctx_lock);
503
Davide Libenzi13389012009-06-30 11:41:11 -0700504 if (req->ki_eventfd != NULL)
505 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 if (req->ki_dtor)
507 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700508 if (req->ki_iovec != &req->ki_inline_vec)
509 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 kmem_cache_free(kiocb_cachep, req);
511 ctx->reqs_active--;
512
513 if (unlikely(!ctx->reqs_active && ctx->dead))
514 wake_up(&ctx->wait);
515}
516
David Howells65f27f32006-11-22 14:55:48 +0000517static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518{
519 spin_lock_irq(&fput_lock);
520 while (likely(!list_empty(&fput_head))) {
521 struct kiocb *req = list_kiocb(fput_head.next);
522 struct kioctx *ctx = req->ki_ctx;
523
524 list_del(&req->ki_list);
525 spin_unlock_irq(&fput_lock);
526
Davide Libenzi87c3a862009-03-18 17:04:19 -0700527 /* Complete the fput(s) */
528 if (req->ki_filp != NULL)
529 __fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531 /* Link the iocb into the context's free list */
532 spin_lock_irq(&ctx->ctx_lock);
533 really_put_req(ctx, req);
534 spin_unlock_irq(&ctx->ctx_lock);
535
536 put_ioctx(ctx);
537 spin_lock_irq(&fput_lock);
538 }
539 spin_unlock_irq(&fput_lock);
540}
541
542/* __aio_put_req
543 * Returns true if this put was the last user of the request.
544 */
545static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
546{
Al Viro516e0cc2008-07-26 00:39:17 -0400547 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
548 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
Zach Brownd00689a2005-11-13 16:07:34 -0800550 assert_spin_locked(&ctx->ctx_lock);
551
Davide Libenzi87c3a862009-03-18 17:04:19 -0700552 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100553 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 if (likely(req->ki_users))
555 return 0;
556 list_del(&req->ki_list); /* remove from active_reqs */
557 req->ki_cancel = NULL;
558 req->ki_retry = NULL;
559
Davide Libenzi87c3a862009-03-18 17:04:19 -0700560 /*
561 * Try to optimize the aio and eventfd file* puts, by avoiding to
562 * schedule work in case it is not __fput() time. In normal cases,
563 * we would not be holding the last reference to the file*, so
564 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 */
Davide Libenzi13389012009-06-30 11:41:11 -0700566 if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 get_ioctx(ctx);
568 spin_lock(&fput_lock);
569 list_add(&req->ki_list, &fput_head);
570 spin_unlock(&fput_lock);
571 queue_work(aio_wq, &fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700572 } else {
573 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700575 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 return 1;
577}
578
579/* aio_put_req
580 * Returns true if this put was the last user of the kiocb,
581 * false if the request is still in use.
582 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800583int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584{
585 struct kioctx *ctx = req->ki_ctx;
586 int ret;
587 spin_lock_irq(&ctx->ctx_lock);
588 ret = __aio_put_req(ctx, req);
589 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 return ret;
591}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700592EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
Adrian Bunkd5470b52008-04-29 00:58:57 -0700594static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
Jens Axboeabf137d2008-12-09 08:11:22 +0100596 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700597 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100598 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
Jens Axboeabf137d2008-12-09 08:11:22 +0100600 rcu_read_lock();
601
602 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
603 if (ctx->user_id == ctx_id && !ctx->dead) {
604 get_ioctx(ctx);
Jeff Moyer65c24492009-03-18 17:04:21 -0700605 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 break;
607 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100608 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609
Jens Axboeabf137d2008-12-09 08:11:22 +0100610 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700611 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612}
613
614/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 * Queue up a kiocb to be retried. Assumes that the kiocb
616 * has already been marked as kicked, and places it on
617 * the retry run list for the corresponding ioctx, if it
618 * isn't already queued. Returns 1 if it actually queued
619 * the kiocb (to tell the caller to activate the work
620 * queue to process it), or 0, if it found that it was
621 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 */
623static inline int __queue_kicked_iocb(struct kiocb *iocb)
624{
625 struct kioctx *ctx = iocb->ki_ctx;
626
Zach Brownd00689a2005-11-13 16:07:34 -0800627 assert_spin_locked(&ctx->ctx_lock);
628
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 if (list_empty(&iocb->ki_run_list)) {
630 list_add_tail(&iocb->ki_run_list,
631 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 return 1;
633 }
634 return 0;
635}
636
637/* aio_run_iocb
638 * This is the core aio execution routine. It is
639 * invoked both for initial i/o submission and
640 * subsequent retries via the aio_kick_handler.
641 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200642 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 * as needed during processing.
644 *
645 * Calls the iocb retry method (already setup for the
646 * iocb on initial submission) for operation specific
647 * handling, but takes care of most of common retry
648 * execution details for a given iocb. The retry method
649 * needs to be non-blocking as far as possible, to avoid
650 * holding up other iocbs waiting to be serviced by the
651 * retry kernel thread.
652 *
653 * The trickier parts in this code have to do with
654 * ensuring that only one retry instance is in progress
655 * for a given iocb at any time. Providing that guarantee
656 * simplifies the coding of individual aio operations as
657 * it avoids various potential races.
658 */
659static ssize_t aio_run_iocb(struct kiocb *iocb)
660{
661 struct kioctx *ctx = iocb->ki_ctx;
662 ssize_t (*retry)(struct kiocb *);
663 ssize_t ret;
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 if (!(retry = iocb->ki_retry)) {
666 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
667 return 0;
668 }
669
670 /*
671 * We don't want the next retry iteration for this
672 * operation to start until this one has returned and
673 * updated the iocb state. However, wait_queue functions
674 * can trigger a kick_iocb from interrupt context in the
675 * meantime, indicating that data is available for the next
676 * iteration. We want to remember that and enable the
677 * next retry iteration _after_ we are through with
678 * this one.
679 *
680 * So, in order to be able to register a "kick", but
681 * prevent it from being queued now, we clear the kick
682 * flag, but make the kick code *think* that the iocb is
683 * still on the run list until we are actually done.
684 * When we are done with this iteration, we check if
685 * the iocb was kicked in the meantime and if so, queue
686 * it up afresh.
687 */
688
689 kiocbClearKicked(iocb);
690
691 /*
692 * This is so that aio_complete knows it doesn't need to
693 * pull the iocb off the run list (We can't just call
694 * INIT_LIST_HEAD because we don't want a kick_iocb to
695 * queue this on the run list yet)
696 */
697 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
698 spin_unlock_irq(&ctx->ctx_lock);
699
700 /* Quit retrying if the i/o has been cancelled */
701 if (kiocbIsCancelled(iocb)) {
702 ret = -EINTR;
703 aio_complete(iocb, ret, 0);
704 /* must not access the iocb after this */
705 goto out;
706 }
707
708 /*
709 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700710 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Shaohua Lifac046a2009-12-15 16:47:47 -0800714 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED)
Zach Brown897f15f2005-09-30 11:58:55 -0700715 aio_complete(iocb, ret, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716out:
717 spin_lock_irq(&ctx->ctx_lock);
718
719 if (-EIOCBRETRY == ret) {
720 /*
721 * OK, now that we are done with this iteration
722 * and know that there is more left to go,
723 * this is where we let go so that a subsequent
724 * "kick" can start the next iteration
725 */
726
727 /* will make __queue_kicked_iocb succeed from here on */
728 INIT_LIST_HEAD(&iocb->ki_run_list);
729 /* we must queue the next iteration ourselves, if it
730 * has already been kicked */
731 if (kiocbIsKicked(iocb)) {
732 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700733
734 /*
735 * __queue_kicked_iocb will always return 1 here, because
736 * iocb->ki_run_list is empty at this point so it should
737 * be safe to unconditionally queue the context into the
738 * work queue.
739 */
740 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 }
742 }
743 return ret;
744}
745
746/*
747 * __aio_run_iocbs:
748 * Process all pending retries queued on the ioctx
749 * run list.
750 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800751 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 */
753static int __aio_run_iocbs(struct kioctx *ctx)
754{
755 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700756 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
Zach Brownd00689a2005-11-13 16:07:34 -0800758 assert_spin_locked(&ctx->ctx_lock);
759
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700760 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 while (!list_empty(&run_list)) {
762 iocb = list_entry(run_list.next, struct kiocb,
763 ki_run_list);
764 list_del(&iocb->ki_run_list);
765 /*
766 * Hold an extra reference while retrying i/o.
767 */
768 iocb->ki_users++; /* grab extra reference */
769 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800770 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 if (!list_empty(&ctx->run_list))
773 return 1;
774 return 0;
775}
776
777static void aio_queue_work(struct kioctx * ctx)
778{
779 unsigned long timeout;
780 /*
781 * if someone is waiting, get the work started right
782 * away, otherwise, use a longer delay
783 */
784 smp_mb();
785 if (waitqueue_active(&ctx->wait))
786 timeout = 1;
787 else
788 timeout = HZ/10;
789 queue_delayed_work(aio_wq, &ctx->wq, timeout);
790}
791
792
793/*
794 * aio_run_iocbs:
795 * Process all pending retries queued on the ioctx
796 * run list.
797 * Assumes it is operating within the aio issuer's mm
798 * context.
799 */
800static inline void aio_run_iocbs(struct kioctx *ctx)
801{
802 int requeue;
803
804 spin_lock_irq(&ctx->ctx_lock);
805
806 requeue = __aio_run_iocbs(ctx);
807 spin_unlock_irq(&ctx->ctx_lock);
808 if (requeue)
809 aio_queue_work(ctx);
810}
811
812/*
813 * just like aio_run_iocbs, but keeps running them until
814 * the list stays empty
815 */
816static inline void aio_run_all_iocbs(struct kioctx *ctx)
817{
818 spin_lock_irq(&ctx->ctx_lock);
819 while (__aio_run_iocbs(ctx))
820 ;
821 spin_unlock_irq(&ctx->ctx_lock);
822}
823
824/*
825 * aio_kick_handler:
826 * Work queue handler triggered to process pending
827 * retries on an ioctx. Takes on the aio issuer's
828 * mm context before running the iocbs, so that
829 * copy_xxx_user operates on the issuer's address
830 * space.
831 * Run on aiod's context.
832 */
David Howells65f27f32006-11-22 14:55:48 +0000833static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834{
David Howells65f27f32006-11-22 14:55:48 +0000835 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800837 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 int requeue;
839
840 set_fs(USER_DS);
841 use_mm(ctx->mm);
842 spin_lock_irq(&ctx->ctx_lock);
843 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800844 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800846 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 set_fs(oldfs);
848 /*
849 * we're in a worker thread already, don't use queue_delayed_work,
850 */
851 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000852 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853}
854
855
856/*
857 * Called by kick_iocb to queue the kiocb for retry
858 * and if required activate the aio work queue to process
859 * it
860 */
Zach Brown998765e2005-09-30 11:58:54 -0700861static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862{
863 struct kioctx *ctx = iocb->ki_ctx;
864 unsigned long flags;
865 int run = 0;
866
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700868 /* set this inside the lock so that we can't race with aio_run_iocb()
869 * testing it and putting the iocb on the run list under the lock */
870 if (!kiocbTryKick(iocb))
871 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700873 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875}
876
877/*
878 * kick_iocb:
879 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800880 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 * The retry is usually executed by aio workqueue
882 * threads (See aio_kick_handler).
883 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800884void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885{
886 /* sync iocbs are easy: they can only ever be executing from a
887 * single context. */
888 if (is_sync_kiocb(iocb)) {
889 kiocbSetKicked(iocb);
890 wake_up_process(iocb->ki_obj.tsk);
891 return;
892 }
893
Zach Brown998765e2005-09-30 11:58:54 -0700894 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895}
896EXPORT_SYMBOL(kick_iocb);
897
898/* aio_complete
899 * Called when the io request on the given iocb is complete.
900 * Returns true if this is the last user of the request. The
901 * only other user of the request can be the cancellation code.
902 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800903int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904{
905 struct kioctx *ctx = iocb->ki_ctx;
906 struct aio_ring_info *info;
907 struct aio_ring *ring;
908 struct io_event *event;
909 unsigned long flags;
910 unsigned long tail;
911 int ret;
912
Zach Brown20dcae32005-11-13 16:07:33 -0800913 /*
914 * Special case handling for sync iocbs:
915 * - events go directly into the iocb for fast handling
916 * - the sync task with the iocb in its stack holds the single iocb
917 * ref, no other paths have a way to get another ref
918 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 */
920 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800921 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800923 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800925 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 }
927
928 info = &ctx->ring_info;
929
930 /* add a completion event to the ring buffer.
931 * must be done holding ctx->ctx_lock to prevent
932 * other code from messing with the tail
933 * pointer since we might be called from irq
934 * context.
935 */
936 spin_lock_irqsave(&ctx->ctx_lock, flags);
937
938 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
939 list_del_init(&iocb->ki_run_list);
940
941 /*
942 * cancelled requests don't get events, userland was given one
943 * when the event got cancelled.
944 */
945 if (kiocbIsCancelled(iocb))
946 goto put_rq;
947
948 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
949
950 tail = info->tail;
951 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700952 if (++tail >= info->nr)
953 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954
955 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
956 event->data = iocb->ki_user_data;
957 event->res = res;
958 event->res2 = res2;
959
960 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
961 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
962 res, res2);
963
964 /* after flagging the request as done, we
965 * must never even look at it again
966 */
967 smp_wmb(); /* make event visible before updating tail */
968
969 info->tail = tail;
970 ring->tail = tail;
971
972 put_aio_ring_event(event, KM_IRQ0);
973 kunmap_atomic(ring, KM_IRQ1);
974
975 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700976
977 /*
978 * Check if the user asked us to deliver the result through an
979 * eventfd. The eventfd_signal() function is safe to be called
980 * from IRQ context.
981 */
Davide Libenzi87c3a862009-03-18 17:04:19 -0700982 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700983 eventfd_signal(iocb->ki_eventfd, 1);
984
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985put_rq:
986 /* everything turned out well, dispose of the aiocb. */
987 ret = __aio_put_req(ctx, iocb);
988
Quentin Barnes6cb2a212008-03-19 17:00:39 -0700989 /*
990 * We have to order our ring_info tail store above and test
991 * of the wait list below outside the wait lock. This is
992 * like in wake_up_bit() where clearing a bit has to be
993 * ordered with the unlocked test.
994 */
995 smp_mb();
996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 if (waitqueue_active(&ctx->wait))
998 wake_up(&ctx->wait);
999
Ken Chendee11c22007-02-03 01:13:45 -08001000 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 return ret;
1002}
H Hartley Sweeten385773e2009-09-22 16:43:53 -07001003EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004
1005/* aio_read_evt
1006 * Pull an event off of the ioctx's event ring. Returns the number of
1007 * events fetched (0 or 1 ;-)
1008 * FIXME: make this use cmpxchg.
1009 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1010 */
1011static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1012{
1013 struct aio_ring_info *info = &ioctx->ring_info;
1014 struct aio_ring *ring;
1015 unsigned long head;
1016 int ret = 0;
1017
1018 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1019 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1020 (unsigned long)ring->head, (unsigned long)ring->tail,
1021 (unsigned long)ring->nr);
1022
1023 if (ring->head == ring->tail)
1024 goto out;
1025
1026 spin_lock(&info->ring_lock);
1027
1028 head = ring->head % info->nr;
1029 if (head != ring->tail) {
1030 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1031 *ent = *evp;
1032 head = (head + 1) % info->nr;
1033 smp_mb(); /* finish reading the event before updatng the head */
1034 ring->head = head;
1035 ret = 1;
1036 put_aio_ring_event(evp, KM_USER1);
1037 }
1038 spin_unlock(&info->ring_lock);
1039
1040out:
1041 kunmap_atomic(ring, KM_USER0);
1042 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1043 (unsigned long)ring->head, (unsigned long)ring->tail);
1044 return ret;
1045}
1046
1047struct aio_timeout {
1048 struct timer_list timer;
1049 int timed_out;
1050 struct task_struct *p;
1051};
1052
1053static void timeout_func(unsigned long data)
1054{
1055 struct aio_timeout *to = (struct aio_timeout *)data;
1056
1057 to->timed_out = 1;
1058 wake_up_process(to->p);
1059}
1060
1061static inline void init_timeout(struct aio_timeout *to)
1062{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001063 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 to->timed_out = 0;
1065 to->p = current;
1066}
1067
1068static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1069 const struct timespec *ts)
1070{
1071 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1072 if (time_after(to->timer.expires, jiffies))
1073 add_timer(&to->timer);
1074 else
1075 to->timed_out = 1;
1076}
1077
1078static inline void clear_timeout(struct aio_timeout *to)
1079{
1080 del_singleshot_timer_sync(&to->timer);
1081}
1082
1083static int read_events(struct kioctx *ctx,
1084 long min_nr, long nr,
1085 struct io_event __user *event,
1086 struct timespec __user *timeout)
1087{
1088 long start_jiffies = jiffies;
1089 struct task_struct *tsk = current;
1090 DECLARE_WAITQUEUE(wait, tsk);
1091 int ret;
1092 int i = 0;
1093 struct io_event ent;
1094 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 int retry = 0;
1096
1097 /* needed to zero any padding within an entry (there shouldn't be
1098 * any, but C is fun!
1099 */
1100 memset(&ent, 0, sizeof(ent));
1101retry:
1102 ret = 0;
1103 while (likely(i < nr)) {
1104 ret = aio_read_evt(ctx, &ent);
1105 if (unlikely(ret <= 0))
1106 break;
1107
1108 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1109 ent.data, ent.obj, ent.res, ent.res2);
1110
1111 /* Could we split the check in two? */
1112 ret = -EFAULT;
1113 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1114 dprintk("aio: lost an event due to EFAULT.\n");
1115 break;
1116 }
1117 ret = 0;
1118
1119 /* Good, event copied to userland, update counts. */
1120 event ++;
1121 i ++;
1122 }
1123
1124 if (min_nr <= i)
1125 return i;
1126 if (ret)
1127 return ret;
1128
1129 /* End fast path */
1130
1131 /* racey check, but it gets redone */
1132 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1133 retry = 1;
1134 aio_run_all_iocbs(ctx);
1135 goto retry;
1136 }
1137
1138 init_timeout(&to);
1139 if (timeout) {
1140 struct timespec ts;
1141 ret = -EFAULT;
1142 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1143 goto out;
1144
1145 set_timeout(start_jiffies, &to, &ts);
1146 }
1147
1148 while (likely(i < nr)) {
1149 add_wait_queue_exclusive(&ctx->wait, &wait);
1150 do {
1151 set_task_state(tsk, TASK_INTERRUPTIBLE);
1152 ret = aio_read_evt(ctx, &ent);
1153 if (ret)
1154 break;
1155 if (min_nr <= i)
1156 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001157 if (unlikely(ctx->dead)) {
1158 ret = -EINVAL;
1159 break;
1160 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 if (to.timed_out) /* Only check after read evt */
1162 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001163 /* Try to only show up in io wait if there are ops
1164 * in flight */
1165 if (ctx->reqs_active)
1166 io_schedule();
1167 else
1168 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 if (signal_pending(tsk)) {
1170 ret = -EINTR;
1171 break;
1172 }
1173 /*ret = aio_read_evt(ctx, &ent);*/
1174 } while (1) ;
1175
1176 set_task_state(tsk, TASK_RUNNING);
1177 remove_wait_queue(&ctx->wait, &wait);
1178
1179 if (unlikely(ret <= 0))
1180 break;
1181
1182 ret = -EFAULT;
1183 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1184 dprintk("aio: lost an event due to EFAULT.\n");
1185 break;
1186 }
1187
1188 /* Good, event copied to userland, update counts. */
1189 event ++;
1190 i ++;
1191 }
1192
1193 if (timeout)
1194 clear_timeout(&to);
1195out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001196 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 return i ? i : ret;
1198}
1199
1200/* Take an ioctx and remove it from the list of ioctx's. Protects
1201 * against races with itself via ->dead.
1202 */
1203static void io_destroy(struct kioctx *ioctx)
1204{
1205 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 int was_dead;
1207
1208 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001209 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 was_dead = ioctx->dead;
1211 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001212 hlist_del_rcu(&ioctx->list);
1213 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214
1215 dprintk("aio_release(%p)\n", ioctx);
1216 if (likely(!was_dead))
1217 put_ioctx(ioctx); /* twice for the list */
1218
1219 aio_cancel_all(ioctx);
1220 wait_for_all_aios(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001221
1222 /*
1223 * Wake up any waiters. The setting of ctx->dead must be seen
1224 * by other CPUs at this point. Right now, we rely on the
1225 * locking done by the above calls to ensure this consistency.
1226 */
1227 wake_up(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 put_ioctx(ioctx); /* once for the lookup */
1229}
1230
1231/* sys_io_setup:
1232 * Create an aio_context capable of receiving at least nr_events.
1233 * ctxp must not point to an aio_context that already exists, and
1234 * must be initialized to 0 prior to the call. On successful
1235 * creation of the aio_context, *ctxp is filled in with the resulting
1236 * handle. May fail with -EINVAL if *ctxp is not initialized,
1237 * if the specified nr_events exceeds internal limits. May fail
1238 * with -EAGAIN if the specified nr_events exceeds the user's limit
1239 * of available events. May fail with -ENOMEM if insufficient kernel
1240 * resources are available. May fail with -EFAULT if an invalid
1241 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1242 * implemented.
1243 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001244SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245{
1246 struct kioctx *ioctx = NULL;
1247 unsigned long ctx;
1248 long ret;
1249
1250 ret = get_user(ctx, ctxp);
1251 if (unlikely(ret))
1252 goto out;
1253
1254 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001255 if (unlikely(ctx || nr_events == 0)) {
1256 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1257 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 goto out;
1259 }
1260
1261 ioctx = ioctx_alloc(nr_events);
1262 ret = PTR_ERR(ioctx);
1263 if (!IS_ERR(ioctx)) {
1264 ret = put_user(ioctx->user_id, ctxp);
1265 if (!ret)
1266 return 0;
1267
1268 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1269 io_destroy(ioctx);
1270 }
1271
1272out:
1273 return ret;
1274}
1275
1276/* sys_io_destroy:
1277 * Destroy the aio_context specified. May cancel any outstanding
1278 * AIOs and block on completion. Will fail with -ENOSYS if not
1279 * implemented. May fail with -EFAULT if the context pointed to
1280 * is invalid.
1281 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001282SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283{
1284 struct kioctx *ioctx = lookup_ioctx(ctx);
1285 if (likely(NULL != ioctx)) {
1286 io_destroy(ioctx);
1287 return 0;
1288 }
1289 pr_debug("EINVAL: io_destroy: invalid context id\n");
1290 return -EINVAL;
1291}
1292
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001293static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1294{
1295 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1296
1297 BUG_ON(ret <= 0);
1298
1299 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1300 ssize_t this = min((ssize_t)iov->iov_len, ret);
1301 iov->iov_base += this;
1302 iov->iov_len -= this;
1303 iocb->ki_left -= this;
1304 ret -= this;
1305 if (iov->iov_len == 0) {
1306 iocb->ki_cur_seg++;
1307 iov++;
1308 }
1309 }
1310
1311 /* the caller should not have done more io than what fit in
1312 * the remaining iovecs */
1313 BUG_ON(ret > 0 && iocb->ki_left == 0);
1314}
1315
1316static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317{
1318 struct file *file = iocb->ki_filp;
1319 struct address_space *mapping = file->f_mapping;
1320 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001321 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1322 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001324 unsigned short opcode;
1325
1326 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1327 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1328 rw_op = file->f_op->aio_read;
1329 opcode = IOCB_CMD_PREADV;
1330 } else {
1331 rw_op = file->f_op->aio_write;
1332 opcode = IOCB_CMD_PWRITEV;
1333 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334
Rusty Russellc2ec6682008-02-08 04:20:15 -08001335 /* This matches the pread()/pwrite() logic */
1336 if (iocb->ki_pos < 0)
1337 return -EINVAL;
1338
Zach Brown897f15f2005-09-30 11:58:55 -07001339 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001340 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1341 iocb->ki_nr_segs - iocb->ki_cur_seg,
1342 iocb->ki_pos);
1343 if (ret > 0)
1344 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001345
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001346 /* retry all partial writes. retry partial reads as long as its a
1347 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001348 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001349 (opcode == IOCB_CMD_PWRITEV ||
1350 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351
1352 /* This means we must have transferred all that we could */
1353 /* No need to retry anymore */
1354 if ((ret == 0) || (iocb->ki_left == 0))
1355 ret = iocb->ki_nbytes - iocb->ki_left;
1356
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001357 /* If we managed to write some out we return that, rather than
1358 * the eventual error. */
1359 if (opcode == IOCB_CMD_PWRITEV
1360 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1361 && iocb->ki_nbytes - iocb->ki_left)
1362 ret = iocb->ki_nbytes - iocb->ki_left;
1363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 return ret;
1365}
1366
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367static ssize_t aio_fdsync(struct kiocb *iocb)
1368{
1369 struct file *file = iocb->ki_filp;
1370 ssize_t ret = -EINVAL;
1371
1372 if (file->f_op->aio_fsync)
1373 ret = file->f_op->aio_fsync(iocb, 1);
1374 return ret;
1375}
1376
1377static ssize_t aio_fsync(struct kiocb *iocb)
1378{
1379 struct file *file = iocb->ki_filp;
1380 ssize_t ret = -EINVAL;
1381
1382 if (file->f_op->aio_fsync)
1383 ret = file->f_op->aio_fsync(iocb, 0);
1384 return ret;
1385}
1386
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001387static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
1388{
1389 ssize_t ret;
1390
1391 ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
1392 kiocb->ki_nbytes, 1,
1393 &kiocb->ki_inline_vec, &kiocb->ki_iovec);
1394 if (ret < 0)
1395 goto out;
1396
1397 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1398 kiocb->ki_cur_seg = 0;
1399 /* ki_nbytes/left now reflect bytes instead of segs */
1400 kiocb->ki_nbytes = ret;
1401 kiocb->ki_left = ret;
1402
1403 ret = 0;
1404out:
1405 return ret;
1406}
1407
1408static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1409{
1410 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1411 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1412 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1413 kiocb->ki_nr_segs = 1;
1414 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001415 return 0;
1416}
1417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418/*
1419 * aio_setup_iocb:
1420 * Performs the initial checks and aio retry method
1421 * setup for the kiocb at the time of io submission.
1422 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001423static ssize_t aio_setup_iocb(struct kiocb *kiocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424{
1425 struct file *file = kiocb->ki_filp;
1426 ssize_t ret = 0;
1427
1428 switch (kiocb->ki_opcode) {
1429 case IOCB_CMD_PREAD:
1430 ret = -EBADF;
1431 if (unlikely(!(file->f_mode & FMODE_READ)))
1432 break;
1433 ret = -EFAULT;
1434 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1435 kiocb->ki_left)))
1436 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001437 ret = security_file_permission(file, MAY_READ);
1438 if (unlikely(ret))
1439 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001440 ret = aio_setup_single_vector(kiocb);
1441 if (ret)
1442 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 ret = -EINVAL;
1444 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001445 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 break;
1447 case IOCB_CMD_PWRITE:
1448 ret = -EBADF;
1449 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1450 break;
1451 ret = -EFAULT;
1452 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1453 kiocb->ki_left)))
1454 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001455 ret = security_file_permission(file, MAY_WRITE);
1456 if (unlikely(ret))
1457 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001458 ret = aio_setup_single_vector(kiocb);
1459 if (ret)
1460 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 ret = -EINVAL;
1462 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001463 kiocb->ki_retry = aio_rw_vect_retry;
1464 break;
1465 case IOCB_CMD_PREADV:
1466 ret = -EBADF;
1467 if (unlikely(!(file->f_mode & FMODE_READ)))
1468 break;
1469 ret = security_file_permission(file, MAY_READ);
1470 if (unlikely(ret))
1471 break;
1472 ret = aio_setup_vectored_rw(READ, kiocb);
1473 if (ret)
1474 break;
1475 ret = -EINVAL;
1476 if (file->f_op->aio_read)
1477 kiocb->ki_retry = aio_rw_vect_retry;
1478 break;
1479 case IOCB_CMD_PWRITEV:
1480 ret = -EBADF;
1481 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1482 break;
1483 ret = security_file_permission(file, MAY_WRITE);
1484 if (unlikely(ret))
1485 break;
1486 ret = aio_setup_vectored_rw(WRITE, kiocb);
1487 if (ret)
1488 break;
1489 ret = -EINVAL;
1490 if (file->f_op->aio_write)
1491 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 break;
1493 case IOCB_CMD_FDSYNC:
1494 ret = -EINVAL;
1495 if (file->f_op->aio_fsync)
1496 kiocb->ki_retry = aio_fdsync;
1497 break;
1498 case IOCB_CMD_FSYNC:
1499 ret = -EINVAL;
1500 if (file->f_op->aio_fsync)
1501 kiocb->ki_retry = aio_fsync;
1502 break;
1503 default:
1504 dprintk("EINVAL: io_submit: no operation provided\n");
1505 ret = -EINVAL;
1506 }
1507
1508 if (!kiocb->ki_retry)
1509 return ret;
1510
1511 return 0;
1512}
1513
Jeff Moyercfb1e332009-10-02 18:57:36 -04001514static void aio_batch_add(struct address_space *mapping,
1515 struct hlist_head *batch_hash)
1516{
1517 struct aio_batch_entry *abe;
1518 struct hlist_node *pos;
1519 unsigned bucket;
1520
1521 bucket = hash_ptr(mapping, AIO_BATCH_HASH_BITS);
1522 hlist_for_each_entry(abe, pos, &batch_hash[bucket], list) {
1523 if (abe->mapping == mapping)
1524 return;
1525 }
1526
1527 abe = mempool_alloc(abe_pool, GFP_KERNEL);
1528 BUG_ON(!igrab(mapping->host));
1529 abe->mapping = mapping;
1530 hlist_add_head(&abe->list, &batch_hash[bucket]);
1531 return;
1532}
1533
1534static void aio_batch_free(struct hlist_head *batch_hash)
1535{
1536 struct aio_batch_entry *abe;
1537 struct hlist_node *pos, *n;
1538 int i;
1539
1540 for (i = 0; i < AIO_BATCH_HASH_SIZE; i++) {
1541 hlist_for_each_entry_safe(abe, pos, n, &batch_hash[i], list) {
1542 blk_run_address_space(abe->mapping);
1543 iput(abe->mapping->host);
1544 hlist_del(&abe->list);
1545 mempool_free(abe, abe_pool);
1546 }
1547 }
1548}
1549
Adrian Bunkd5470b52008-04-29 00:58:57 -07001550static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyercfb1e332009-10-02 18:57:36 -04001551 struct iocb *iocb, struct hlist_head *batch_hash)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552{
1553 struct kiocb *req;
1554 struct file *file;
1555 ssize_t ret;
1556
1557 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001558 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559 pr_debug("EINVAL: io_submit: reserve field set\n");
1560 return -EINVAL;
1561 }
1562
1563 /* prevent overflows */
1564 if (unlikely(
1565 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1566 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1567 ((ssize_t)iocb->aio_nbytes < 0)
1568 )) {
1569 pr_debug("EINVAL: io_submit: overflow check\n");
1570 return -EINVAL;
1571 }
1572
1573 file = fget(iocb->aio_fildes);
1574 if (unlikely(!file))
1575 return -EBADF;
1576
1577 req = aio_get_req(ctx); /* returns with 2 references to req */
1578 if (unlikely(!req)) {
1579 fput(file);
1580 return -EAGAIN;
1581 }
Yan Zheng87e28312007-10-08 12:16:20 -07001582 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001583 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1584 /*
1585 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1586 * instance of the file* now. The file descriptor must be
1587 * an eventfd() fd, and will be signaled for each completed
1588 * event using the eventfd_signal() function.
1589 */
Davide Libenzi13389012009-06-30 11:41:11 -07001590 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001591 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001592 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001593 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001594 goto out_put_req;
1595 }
1596 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597
Ken Chen212079c2005-05-01 08:59:15 -07001598 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 if (unlikely(ret)) {
1600 dprintk("EFAULT: aio_key\n");
1601 goto out_put_req;
1602 }
1603
1604 req->ki_obj.user = user_iocb;
1605 req->ki_user_data = iocb->aio_data;
1606 req->ki_pos = iocb->aio_offset;
1607
1608 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1609 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1610 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611
1612 ret = aio_setup_iocb(req);
1613
1614 if (ret)
1615 goto out_put_req;
1616
1617 spin_lock_irq(&ctx->ctx_lock);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001618 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001619 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001620 /* drain the run list */
1621 while (__aio_run_iocbs(ctx))
1622 ;
1623 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001625 if (req->ki_opcode == IOCB_CMD_PREAD ||
1626 req->ki_opcode == IOCB_CMD_PREADV ||
1627 req->ki_opcode == IOCB_CMD_PWRITE ||
1628 req->ki_opcode == IOCB_CMD_PWRITEV)
1629 aio_batch_add(file->f_mapping, batch_hash);
1630
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 aio_put_req(req); /* drop extra ref to req */
1632 return 0;
1633
1634out_put_req:
1635 aio_put_req(req); /* drop extra ref to req */
1636 aio_put_req(req); /* drop i/o ref to req */
1637 return ret;
1638}
1639
1640/* sys_io_submit:
1641 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1642 * the number of iocbs queued. May return -EINVAL if the aio_context
1643 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1644 * *iocbpp[0] is not properly initialized, if the operation specified
1645 * is invalid for the file descriptor in the iocb. May fail with
1646 * -EFAULT if any of the data structures point to invalid data. May
1647 * fail with -EBADF if the file descriptor specified in the first
1648 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1649 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1650 * fail with -ENOSYS if not implemented.
1651 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001652SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1653 struct iocb __user * __user *, iocbpp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654{
1655 struct kioctx *ctx;
1656 long ret = 0;
1657 int i;
Jeff Moyercfb1e332009-10-02 18:57:36 -04001658 struct hlist_head batch_hash[AIO_BATCH_HASH_SIZE] = { { 0, }, };
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659
1660 if (unlikely(nr < 0))
1661 return -EINVAL;
1662
1663 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1664 return -EFAULT;
1665
1666 ctx = lookup_ioctx(ctx_id);
1667 if (unlikely(!ctx)) {
1668 pr_debug("EINVAL: io_submit: invalid context id\n");
1669 return -EINVAL;
1670 }
1671
1672 /*
1673 * AKPM: should this return a partial result if some of the IOs were
1674 * successfully submitted?
1675 */
1676 for (i=0; i<nr; i++) {
1677 struct iocb __user *user_iocb;
1678 struct iocb tmp;
1679
1680 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1681 ret = -EFAULT;
1682 break;
1683 }
1684
1685 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1686 ret = -EFAULT;
1687 break;
1688 }
1689
Jeff Moyercfb1e332009-10-02 18:57:36 -04001690 ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 if (ret)
1692 break;
1693 }
Jeff Moyercfb1e332009-10-02 18:57:36 -04001694 aio_batch_free(batch_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695
1696 put_ioctx(ctx);
1697 return i ? i : ret;
1698}
1699
1700/* lookup_kiocb
1701 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001703static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1704 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705{
1706 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001707
1708 assert_spin_locked(&ctx->ctx_lock);
1709
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 /* TODO: use a hash or array, this sucks. */
1711 list_for_each(pos, &ctx->active_reqs) {
1712 struct kiocb *kiocb = list_kiocb(pos);
1713 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1714 return kiocb;
1715 }
1716 return NULL;
1717}
1718
1719/* sys_io_cancel:
1720 * Attempts to cancel an iocb previously passed to io_submit. If
1721 * the operation is successfully cancelled, the resulting event is
1722 * copied into the memory pointed to by result without being placed
1723 * into the completion queue and 0 is returned. May fail with
1724 * -EFAULT if any of the data structures pointed to are invalid.
1725 * May fail with -EINVAL if aio_context specified by ctx_id is
1726 * invalid. May fail with -EAGAIN if the iocb specified was not
1727 * cancelled. Will fail with -ENOSYS if not implemented.
1728 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001729SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1730 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731{
1732 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1733 struct kioctx *ctx;
1734 struct kiocb *kiocb;
1735 u32 key;
1736 int ret;
1737
1738 ret = get_user(key, &iocb->aio_key);
1739 if (unlikely(ret))
1740 return -EFAULT;
1741
1742 ctx = lookup_ioctx(ctx_id);
1743 if (unlikely(!ctx))
1744 return -EINVAL;
1745
1746 spin_lock_irq(&ctx->ctx_lock);
1747 ret = -EAGAIN;
1748 kiocb = lookup_kiocb(ctx, iocb, key);
1749 if (kiocb && kiocb->ki_cancel) {
1750 cancel = kiocb->ki_cancel;
1751 kiocb->ki_users ++;
1752 kiocbSetCancelled(kiocb);
1753 } else
1754 cancel = NULL;
1755 spin_unlock_irq(&ctx->ctx_lock);
1756
1757 if (NULL != cancel) {
1758 struct io_event tmp;
1759 pr_debug("calling cancel\n");
1760 memset(&tmp, 0, sizeof(tmp));
1761 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1762 tmp.data = kiocb->ki_user_data;
1763 ret = cancel(kiocb, &tmp);
1764 if (!ret) {
1765 /* Cancellation succeeded -- copy the result
1766 * into the user's buffer.
1767 */
1768 if (copy_to_user(result, &tmp, sizeof(tmp)))
1769 ret = -EFAULT;
1770 }
1771 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001772 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773
1774 put_ioctx(ctx);
1775
1776 return ret;
1777}
1778
1779/* io_getevents:
1780 * Attempts to read at least min_nr events and up to nr events from
1781 * the completion queue for the aio_context specified by ctx_id. May
1782 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1783 * if nr is out of range, if when is out of range. May fail with
1784 * -EFAULT if any of the memory specified to is invalid. May return
1785 * 0 or < min_nr if no events are available and the timeout specified
1786 * by when has elapsed, where when == NULL specifies an infinite
1787 * timeout. Note that the timeout pointed to by when is relative and
1788 * will be updated if not NULL and the operation blocks. Will fail
1789 * with -ENOSYS if not implemented.
1790 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001791SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1792 long, min_nr,
1793 long, nr,
1794 struct io_event __user *, events,
1795 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796{
1797 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1798 long ret = -EINVAL;
1799
1800 if (likely(ioctx)) {
1801 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1802 ret = read_events(ioctx, min_nr, nr, events, timeout);
1803 put_ioctx(ioctx);
1804 }
1805
Roland McGrath598af052008-04-10 15:38:45 -07001806 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 return ret;
1808}