blob: 4f71627264fd9276d6acb3b94f3ee5316372a394 [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>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050016#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#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
Cong Wange8e3c3d2011-11-25 23:14:27 +0800163 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 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);
Cong Wange8e3c3d2011-11-25 23:14:27 +0800171 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
173 return 0;
174}
175
176
177/* aio_ring_event: returns a pointer to the event at the given index from
Cong Wange8e3c3d2011-11-25 23:14:27 +0800178 * kmap_atomic(). Release the pointer with put_aio_ring_event();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 */
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
Cong Wange8e3c3d2011-11-25 23:14:27 +0800184#define aio_ring_event(info, nr) ({ \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
186 struct io_event *__event; \
187 __event = kmap_atomic( \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800188 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 __event += pos % AIO_EVENTS_PER_PAGE; \
190 __event; \
191})
192
Cong Wange8e3c3d2011-11-25 23:14:27 +0800193#define put_aio_ring_event(event) do { \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 struct io_event *__event = (event); \
195 (void)__event; \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800196 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197} 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 kmem_cache_free(kioctx_cachep, ctx);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700203}
204
Jens Axboeabf137d2008-12-09 08:11:22 +0100205/* __put_ioctx
206 * Called when the last user of an aio context has gone away,
207 * and the struct needs to be freed.
208 */
209static void __put_ioctx(struct kioctx *ctx)
210{
Al Viro2dd542b2012-03-10 23:10:35 -0500211 unsigned nr_events = ctx->max_reqs;
Jens Axboeabf137d2008-12-09 08:11:22 +0100212 BUG_ON(ctx->reqs_active);
213
Al Virobf507222012-03-11 00:58:40 -0500214 cancel_delayed_work_sync(&ctx->wq);
Jens Axboeabf137d2008-12-09 08:11:22 +0100215 aio_free_ring(ctx);
216 mmdrop(ctx->mm);
217 ctx->mm = NULL;
Al Viro2dd542b2012-03-10 23:10:35 -0500218 if (nr_events) {
219 spin_lock(&aio_nr_lock);
220 BUG_ON(aio_nr - nr_events > aio_nr);
221 aio_nr -= nr_events;
222 spin_unlock(&aio_nr_lock);
223 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100224 pr_debug("__put_ioctx: freeing %p\n", ctx);
225 call_rcu(&ctx->rcu_head, ctx_rcu_free);
226}
227
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800228static inline int try_get_ioctx(struct kioctx *kioctx)
229{
230 return atomic_inc_not_zero(&kioctx->users);
231}
232
233static inline void put_ioctx(struct kioctx *kioctx)
234{
235 BUG_ON(atomic_read(&kioctx->users) <= 0);
236 if (unlikely(atomic_dec_and_test(&kioctx->users)))
237 __put_ioctx(kioctx);
238}
Adrian Bunkd5470b52008-04-29 00:58:57 -0700239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240/* ioctx_alloc
241 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
242 */
243static struct kioctx *ioctx_alloc(unsigned nr_events)
244{
245 struct mm_struct *mm;
246 struct kioctx *ctx;
Al Viroe23754f2012-03-06 14:33:22 -0500247 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249 /* Prevent overflows */
250 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
251 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
252 pr_debug("ENOMEM: nr_events too high\n");
253 return ERR_PTR(-EINVAL);
254 }
255
Al Viro2dd542b2012-03-10 23:10:35 -0500256 if (!nr_events || (unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 return ERR_PTR(-EAGAIN);
258
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800259 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 if (!ctx)
261 return ERR_PTR(-ENOMEM);
262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 ctx->max_reqs = nr_events;
264 mm = ctx->mm = current->mm;
265 atomic_inc(&mm->mm_count);
266
Al Viro86b62a22012-03-07 05:16:35 +0000267 atomic_set(&ctx->users, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 spin_lock_init(&ctx->ctx_lock);
269 spin_lock_init(&ctx->ring_info.ring_lock);
270 init_waitqueue_head(&ctx->wait);
271
272 INIT_LIST_HEAD(&ctx->active_reqs);
273 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000274 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
276 if (aio_setup_ring(ctx) < 0)
277 goto out_freectx;
278
279 /* limit the number of system wide aios */
Al Viro9fa1cb32012-03-10 23:14:05 -0500280 spin_lock(&aio_nr_lock);
Al Viro2dd542b2012-03-10 23:10:35 -0500281 if (aio_nr + nr_events > aio_max_nr ||
282 aio_nr + nr_events < aio_nr) {
Al Viro9fa1cb32012-03-10 23:14:05 -0500283 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 goto out_cleanup;
Al Viro2dd542b2012-03-10 23:10:35 -0500285 }
286 aio_nr += ctx->max_reqs;
Al Viro9fa1cb32012-03-10 23:14:05 -0500287 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
Jeff Moyer39fa0032008-04-29 01:03:48 -0700289 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100290 spin_lock(&mm->ioctx_lock);
291 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
292 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
295 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
296 return ctx;
297
298out_cleanup:
Al Viroe23754f2012-03-06 14:33:22 -0500299 err = -EAGAIN;
300 aio_free_ring(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301out_freectx:
302 mmdrop(mm);
303 kmem_cache_free(kioctx_cachep, ctx);
Al Viroe23754f2012-03-06 14:33:22 -0500304 dprintk("aio: error allocating ioctx %d\n", err);
305 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306}
307
308/* aio_cancel_all
309 * Cancels all outstanding aio requests on an aio context. Used
310 * when the processes owning a context have all exited to encourage
311 * the rapid destruction of the kioctx.
312 */
313static void aio_cancel_all(struct kioctx *ctx)
314{
315 int (*cancel)(struct kiocb *, struct io_event *);
316 struct io_event res;
317 spin_lock_irq(&ctx->ctx_lock);
318 ctx->dead = 1;
319 while (!list_empty(&ctx->active_reqs)) {
320 struct list_head *pos = ctx->active_reqs.next;
321 struct kiocb *iocb = list_kiocb(pos);
322 list_del_init(&iocb->ki_list);
323 cancel = iocb->ki_cancel;
324 kiocbSetCancelled(iocb);
325 if (cancel) {
326 iocb->ki_users++;
327 spin_unlock_irq(&ctx->ctx_lock);
328 cancel(iocb, &res);
329 spin_lock_irq(&ctx->ctx_lock);
330 }
331 }
332 spin_unlock_irq(&ctx->ctx_lock);
333}
334
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700335static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336{
337 struct task_struct *tsk = current;
338 DECLARE_WAITQUEUE(wait, tsk);
339
Ken Chendee11c22007-02-03 01:13:45 -0800340 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800342 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
344 add_wait_queue(&ctx->wait, &wait);
345 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
346 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800347 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700348 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800350 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 }
352 __set_task_state(tsk, TASK_RUNNING);
353 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800354
355out:
356 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357}
358
359/* wait_on_sync_kiocb:
360 * Waits on the given sync kiocb to complete.
361 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800362ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
364 while (iocb->ki_users) {
365 set_current_state(TASK_UNINTERRUPTIBLE);
366 if (!iocb->ki_users)
367 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700368 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 }
370 __set_current_state(TASK_RUNNING);
371 return iocb->ki_user_data;
372}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700373EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
375/* exit_aio: called when the last user of mm goes away. At this point,
376 * there is no way for any new requests to be submited or any of the
377 * io_* syscalls to be called on the context. However, there may be
378 * outstanding requests which hold references to the context; as they
379 * go away, they will call put_ioctx and release any pinned memory
380 * associated with the request (held via struct page * references).
381 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800382void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383{
Jens Axboeabf137d2008-12-09 08:11:22 +0100384 struct kioctx *ctx;
385
386 while (!hlist_empty(&mm->ioctx_list)) {
387 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
388 hlist_del_rcu(&ctx->list);
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 aio_cancel_all(ctx);
391
392 wait_for_all_aios(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393
394 if (1 != atomic_read(&ctx->users))
395 printk(KERN_DEBUG
396 "exit_aio:ioctx still alive: %d %d %d\n",
397 atomic_read(&ctx->users), ctx->dead,
398 ctx->reqs_active);
399 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 }
401}
402
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403/* aio_get_req
404 * Allocate a slot for an aio request. Increments the users count
405 * of the kioctx so that the kioctx stays around until all requests are
406 * complete. Returns NULL if no requests are free.
407 *
408 * Returns with kiocb->users set to 2. The io submit code path holds
409 * an extra reference while submitting the i/o.
410 * This prevents races between the aio code path referencing the
411 * req (after submitting it) and aio_complete() freeing the req.
412 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800413static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414{
415 struct kiocb *req = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416
417 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
418 if (unlikely(!req))
419 return NULL;
420
Zach Brown4faa5282005-10-17 16:43:33 -0700421 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 req->ki_users = 2;
423 req->ki_key = 0;
424 req->ki_ctx = ctx;
425 req->ki_cancel = NULL;
426 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 req->ki_dtor = NULL;
428 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700429 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700431 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 return req;
434}
435
Jeff Moyer080d6762011-11-02 13:40:10 -0700436/*
437 * struct kiocb's are allocated in batches to reduce the number of
438 * times the ctx lock is acquired and released.
439 */
440#define KIOCB_BATCH_SIZE 32L
441struct kiocb_batch {
442 struct list_head head;
443 long count; /* number of requests left to allocate */
444};
445
446static void kiocb_batch_init(struct kiocb_batch *batch, long total)
447{
448 INIT_LIST_HEAD(&batch->head);
449 batch->count = total;
450}
451
Gleb Natapov69e47472012-01-08 17:07:28 +0200452static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
Jeff Moyer080d6762011-11-02 13:40:10 -0700453{
454 struct kiocb *req, *n;
455
Gleb Natapov69e47472012-01-08 17:07:28 +0200456 if (list_empty(&batch->head))
457 return;
458
459 spin_lock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700460 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
461 list_del(&req->ki_batch);
Gleb Natapov69e47472012-01-08 17:07:28 +0200462 list_del(&req->ki_list);
Jeff Moyer080d6762011-11-02 13:40:10 -0700463 kmem_cache_free(kiocb_cachep, req);
Gleb Natapov69e47472012-01-08 17:07:28 +0200464 ctx->reqs_active--;
Jeff Moyer080d6762011-11-02 13:40:10 -0700465 }
Jeff Moyer880641b2012-03-05 14:59:12 -0800466 if (unlikely(!ctx->reqs_active && ctx->dead))
467 wake_up_all(&ctx->wait);
Gleb Natapov69e47472012-01-08 17:07:28 +0200468 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700469}
470
471/*
472 * Allocate a batch of kiocbs. This avoids taking and dropping the
473 * context lock a lot during setup.
474 */
475static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
476{
477 unsigned short allocated, to_alloc;
478 long avail;
479 bool called_fput = false;
480 struct kiocb *req, *n;
481 struct aio_ring *ring;
482
483 to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
484 for (allocated = 0; allocated < to_alloc; allocated++) {
485 req = __aio_get_req(ctx);
486 if (!req)
487 /* allocation failed, go with what we've got */
488 break;
489 list_add(&req->ki_batch, &batch->head);
490 }
491
492 if (allocated == 0)
493 goto out;
494
495retry:
496 spin_lock_irq(&ctx->ctx_lock);
497 ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
498
499 avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active;
500 BUG_ON(avail < 0);
501 if (avail == 0 && !called_fput) {
502 /*
503 * Handle a potential starvation case. It is possible that
504 * we hold the last reference on a struct file, causing us
505 * to delay the final fput to non-irq context. In this case,
506 * ctx->reqs_active is artificially high. Calling the fput
507 * routine here may free up a slot in the event completion
508 * ring, allowing this allocation to succeed.
509 */
510 kunmap_atomic(ring);
511 spin_unlock_irq(&ctx->ctx_lock);
512 aio_fput_routine(NULL);
513 called_fput = true;
514 goto retry;
515 }
516
517 if (avail < allocated) {
518 /* Trim back the number of requests. */
519 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
520 list_del(&req->ki_batch);
521 kmem_cache_free(kiocb_cachep, req);
522 if (--allocated <= avail)
523 break;
524 }
525 }
526
527 batch->count -= allocated;
528 list_for_each_entry(req, &batch->head, ki_batch) {
529 list_add(&req->ki_list, &ctx->active_reqs);
530 ctx->reqs_active++;
531 }
532
533 kunmap_atomic(ring);
534 spin_unlock_irq(&ctx->ctx_lock);
535
536out:
537 return allocated;
538}
539
540static inline struct kiocb *aio_get_req(struct kioctx *ctx,
541 struct kiocb_batch *batch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542{
543 struct kiocb *req;
Jeff Moyer080d6762011-11-02 13:40:10 -0700544
545 if (list_empty(&batch->head))
546 if (kiocb_batch_refill(ctx, batch) == 0)
547 return NULL;
548 req = list_first_entry(&batch->head, struct kiocb, ki_batch);
549 list_del(&req->ki_batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 return req;
551}
552
553static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
554{
Zach Brownd00689a2005-11-13 16:07:34 -0800555 assert_spin_locked(&ctx->ctx_lock);
556
Davide Libenzi13389012009-06-30 11:41:11 -0700557 if (req->ki_eventfd != NULL)
558 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if (req->ki_dtor)
560 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700561 if (req->ki_iovec != &req->ki_inline_vec)
562 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 kmem_cache_free(kiocb_cachep, req);
564 ctx->reqs_active--;
565
566 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700567 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568}
569
David Howells65f27f32006-11-22 14:55:48 +0000570static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571{
572 spin_lock_irq(&fput_lock);
573 while (likely(!list_empty(&fput_head))) {
574 struct kiocb *req = list_kiocb(fput_head.next);
575 struct kioctx *ctx = req->ki_ctx;
576
577 list_del(&req->ki_list);
578 spin_unlock_irq(&fput_lock);
579
Davide Libenzi87c3a862009-03-18 17:04:19 -0700580 /* Complete the fput(s) */
581 if (req->ki_filp != NULL)
Al Virod7065da2010-05-26 15:13:55 -0400582 fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583
584 /* Link the iocb into the context's free list */
Al Viroc7b28552012-03-08 17:51:19 +0000585 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 spin_lock_irq(&ctx->ctx_lock);
587 really_put_req(ctx, req);
Al Viroc7b28552012-03-08 17:51:19 +0000588 /*
589 * at that point ctx might've been killed, but actual
590 * freeing is RCU'd
591 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 spin_unlock_irq(&ctx->ctx_lock);
Al Viroc7b28552012-03-08 17:51:19 +0000593 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 spin_lock_irq(&fput_lock);
596 }
597 spin_unlock_irq(&fput_lock);
598}
599
600/* __aio_put_req
601 * Returns true if this put was the last user of the request.
602 */
603static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
604{
Al Viro516e0cc2008-07-26 00:39:17 -0400605 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
606 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
Zach Brownd00689a2005-11-13 16:07:34 -0800608 assert_spin_locked(&ctx->ctx_lock);
609
Davide Libenzi87c3a862009-03-18 17:04:19 -0700610 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100611 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 if (likely(req->ki_users))
613 return 0;
614 list_del(&req->ki_list); /* remove from active_reqs */
615 req->ki_cancel = NULL;
616 req->ki_retry = NULL;
617
Davide Libenzi87c3a862009-03-18 17:04:19 -0700618 /*
619 * Try to optimize the aio and eventfd file* puts, by avoiding to
Al Virod7065da2010-05-26 15:13:55 -0400620 * schedule work in case it is not final fput() time. In normal cases,
Davide Libenzi87c3a862009-03-18 17:04:19 -0700621 * we would not be holding the last reference to the file*, so
622 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 */
Al Virod7065da2010-05-26 15:13:55 -0400624 if (unlikely(!fput_atomic(req->ki_filp))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 spin_lock(&fput_lock);
626 list_add(&req->ki_list, &fput_head);
627 spin_unlock(&fput_lock);
Tejun Heod37adaa2011-01-26 17:42:27 +0100628 schedule_work(&fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700629 } else {
630 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700632 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return 1;
634}
635
636/* aio_put_req
637 * Returns true if this put was the last user of the kiocb,
638 * false if the request is still in use.
639 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800640int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641{
642 struct kioctx *ctx = req->ki_ctx;
643 int ret;
644 spin_lock_irq(&ctx->ctx_lock);
645 ret = __aio_put_req(ctx, req);
646 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 return ret;
648}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700649EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650
Adrian Bunkd5470b52008-04-29 00:58:57 -0700651static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652{
Jens Axboeabf137d2008-12-09 08:11:22 +0100653 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700654 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100655 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
Jens Axboeabf137d2008-12-09 08:11:22 +0100657 rcu_read_lock();
658
659 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800660 /*
661 * RCU protects us against accessing freed memory but
662 * we have to be careful not to get a reference when the
663 * reference count already dropped to 0 (ctx->dead test
664 * is unreliable because of races).
665 */
666 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700667 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 break;
669 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100670 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
Jens Axboeabf137d2008-12-09 08:11:22 +0100672 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700673 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674}
675
676/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 * Queue up a kiocb to be retried. Assumes that the kiocb
678 * has already been marked as kicked, and places it on
679 * the retry run list for the corresponding ioctx, if it
680 * isn't already queued. Returns 1 if it actually queued
681 * the kiocb (to tell the caller to activate the work
682 * queue to process it), or 0, if it found that it was
683 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 */
685static inline int __queue_kicked_iocb(struct kiocb *iocb)
686{
687 struct kioctx *ctx = iocb->ki_ctx;
688
Zach Brownd00689a2005-11-13 16:07:34 -0800689 assert_spin_locked(&ctx->ctx_lock);
690
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 if (list_empty(&iocb->ki_run_list)) {
692 list_add_tail(&iocb->ki_run_list,
693 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 return 1;
695 }
696 return 0;
697}
698
699/* aio_run_iocb
700 * This is the core aio execution routine. It is
701 * invoked both for initial i/o submission and
702 * subsequent retries via the aio_kick_handler.
703 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200704 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 * as needed during processing.
706 *
707 * Calls the iocb retry method (already setup for the
708 * iocb on initial submission) for operation specific
709 * handling, but takes care of most of common retry
710 * execution details for a given iocb. The retry method
711 * needs to be non-blocking as far as possible, to avoid
712 * holding up other iocbs waiting to be serviced by the
713 * retry kernel thread.
714 *
715 * The trickier parts in this code have to do with
716 * ensuring that only one retry instance is in progress
717 * for a given iocb at any time. Providing that guarantee
718 * simplifies the coding of individual aio operations as
719 * it avoids various potential races.
720 */
721static ssize_t aio_run_iocb(struct kiocb *iocb)
722{
723 struct kioctx *ctx = iocb->ki_ctx;
724 ssize_t (*retry)(struct kiocb *);
725 ssize_t ret;
726
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 if (!(retry = iocb->ki_retry)) {
728 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
729 return 0;
730 }
731
732 /*
733 * We don't want the next retry iteration for this
734 * operation to start until this one has returned and
735 * updated the iocb state. However, wait_queue functions
736 * can trigger a kick_iocb from interrupt context in the
737 * meantime, indicating that data is available for the next
738 * iteration. We want to remember that and enable the
739 * next retry iteration _after_ we are through with
740 * this one.
741 *
742 * So, in order to be able to register a "kick", but
743 * prevent it from being queued now, we clear the kick
744 * flag, but make the kick code *think* that the iocb is
745 * still on the run list until we are actually done.
746 * When we are done with this iteration, we check if
747 * the iocb was kicked in the meantime and if so, queue
748 * it up afresh.
749 */
750
751 kiocbClearKicked(iocb);
752
753 /*
754 * This is so that aio_complete knows it doesn't need to
755 * pull the iocb off the run list (We can't just call
756 * INIT_LIST_HEAD because we don't want a kick_iocb to
757 * queue this on the run list yet)
758 */
759 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
760 spin_unlock_irq(&ctx->ctx_lock);
761
762 /* Quit retrying if the i/o has been cancelled */
763 if (kiocbIsCancelled(iocb)) {
764 ret = -EINTR;
765 aio_complete(iocb, ret, 0);
766 /* must not access the iocb after this */
767 goto out;
768 }
769
770 /*
771 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700772 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Jan Karaa0c42ba2010-09-22 13:05:03 -0700776 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
777 /*
778 * There's no easy way to restart the syscall since other AIO's
779 * may be already running. Just fail this IO with EINTR.
780 */
781 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
782 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
783 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700784 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700785 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786out:
787 spin_lock_irq(&ctx->ctx_lock);
788
789 if (-EIOCBRETRY == ret) {
790 /*
791 * OK, now that we are done with this iteration
792 * and know that there is more left to go,
793 * this is where we let go so that a subsequent
794 * "kick" can start the next iteration
795 */
796
797 /* will make __queue_kicked_iocb succeed from here on */
798 INIT_LIST_HEAD(&iocb->ki_run_list);
799 /* we must queue the next iteration ourselves, if it
800 * has already been kicked */
801 if (kiocbIsKicked(iocb)) {
802 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700803
804 /*
805 * __queue_kicked_iocb will always return 1 here, because
806 * iocb->ki_run_list is empty at this point so it should
807 * be safe to unconditionally queue the context into the
808 * work queue.
809 */
810 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 }
812 }
813 return ret;
814}
815
816/*
817 * __aio_run_iocbs:
818 * Process all pending retries queued on the ioctx
819 * run list.
820 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800821 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 */
823static int __aio_run_iocbs(struct kioctx *ctx)
824{
825 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700826 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827
Zach Brownd00689a2005-11-13 16:07:34 -0800828 assert_spin_locked(&ctx->ctx_lock);
829
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700830 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 while (!list_empty(&run_list)) {
832 iocb = list_entry(run_list.next, struct kiocb,
833 ki_run_list);
834 list_del(&iocb->ki_run_list);
835 /*
836 * Hold an extra reference while retrying i/o.
837 */
838 iocb->ki_users++; /* grab extra reference */
839 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800840 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 if (!list_empty(&ctx->run_list))
843 return 1;
844 return 0;
845}
846
847static void aio_queue_work(struct kioctx * ctx)
848{
849 unsigned long timeout;
850 /*
851 * if someone is waiting, get the work started right
852 * away, otherwise, use a longer delay
853 */
854 smp_mb();
855 if (waitqueue_active(&ctx->wait))
856 timeout = 1;
857 else
858 timeout = HZ/10;
859 queue_delayed_work(aio_wq, &ctx->wq, timeout);
860}
861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862/*
Jeff Moyerd3486f82011-01-12 17:01:08 -0800863 * aio_run_all_iocbs:
864 * Process all pending retries queued on the ioctx
865 * run list, and keep running them until the list
866 * stays empty.
867 * Assumes it is operating within the aio issuer's mm context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 */
869static inline void aio_run_all_iocbs(struct kioctx *ctx)
870{
871 spin_lock_irq(&ctx->ctx_lock);
872 while (__aio_run_iocbs(ctx))
873 ;
874 spin_unlock_irq(&ctx->ctx_lock);
875}
876
877/*
878 * aio_kick_handler:
879 * Work queue handler triggered to process pending
880 * retries on an ioctx. Takes on the aio issuer's
881 * mm context before running the iocbs, so that
882 * copy_xxx_user operates on the issuer's address
883 * space.
884 * Run on aiod's context.
885 */
David Howells65f27f32006-11-22 14:55:48 +0000886static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887{
David Howells65f27f32006-11-22 14:55:48 +0000888 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800890 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 int requeue;
892
893 set_fs(USER_DS);
894 use_mm(ctx->mm);
895 spin_lock_irq(&ctx->ctx_lock);
896 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800897 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800899 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 set_fs(oldfs);
901 /*
Al Viro9fcf03d2012-03-13 22:06:28 -0400902 * we're in a worker thread already; no point using non-zero delay
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 */
904 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000905 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906}
907
908
909/*
910 * Called by kick_iocb to queue the kiocb for retry
911 * and if required activate the aio work queue to process
912 * it
913 */
Zach Brown998765e2005-09-30 11:58:54 -0700914static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915{
916 struct kioctx *ctx = iocb->ki_ctx;
917 unsigned long flags;
918 int run = 0;
919
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700921 /* set this inside the lock so that we can't race with aio_run_iocb()
922 * testing it and putting the iocb on the run list under the lock */
923 if (!kiocbTryKick(iocb))
924 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700926 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928}
929
930/*
931 * kick_iocb:
932 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800933 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 * The retry is usually executed by aio workqueue
935 * threads (See aio_kick_handler).
936 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800937void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938{
939 /* sync iocbs are easy: they can only ever be executing from a
940 * single context. */
941 if (is_sync_kiocb(iocb)) {
942 kiocbSetKicked(iocb);
943 wake_up_process(iocb->ki_obj.tsk);
944 return;
945 }
946
Zach Brown998765e2005-09-30 11:58:54 -0700947 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948}
949EXPORT_SYMBOL(kick_iocb);
950
951/* aio_complete
952 * Called when the io request on the given iocb is complete.
953 * Returns true if this is the last user of the request. The
954 * only other user of the request can be the cancellation code.
955 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800956int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957{
958 struct kioctx *ctx = iocb->ki_ctx;
959 struct aio_ring_info *info;
960 struct aio_ring *ring;
961 struct io_event *event;
962 unsigned long flags;
963 unsigned long tail;
964 int ret;
965
Zach Brown20dcae32005-11-13 16:07:33 -0800966 /*
967 * Special case handling for sync iocbs:
968 * - events go directly into the iocb for fast handling
969 * - the sync task with the iocb in its stack holds the single iocb
970 * ref, no other paths have a way to get another ref
971 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 */
973 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800974 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800976 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800978 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 }
980
981 info = &ctx->ring_info;
982
983 /* add a completion event to the ring buffer.
984 * must be done holding ctx->ctx_lock to prevent
985 * other code from messing with the tail
986 * pointer since we might be called from irq
987 * context.
988 */
989 spin_lock_irqsave(&ctx->ctx_lock, flags);
990
991 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
992 list_del_init(&iocb->ki_run_list);
993
994 /*
995 * cancelled requests don't get events, userland was given one
996 * when the event got cancelled.
997 */
998 if (kiocbIsCancelled(iocb))
999 goto put_rq;
1000
Cong Wange8e3c3d2011-11-25 23:14:27 +08001001 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002
1003 tail = info->tail;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001004 event = aio_ring_event(info, tail);
Ken Chen4bf69b22005-05-01 08:59:15 -07001005 if (++tail >= info->nr)
1006 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007
1008 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
1009 event->data = iocb->ki_user_data;
1010 event->res = res;
1011 event->res2 = res2;
1012
1013 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
1014 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
1015 res, res2);
1016
1017 /* after flagging the request as done, we
1018 * must never even look at it again
1019 */
1020 smp_wmb(); /* make event visible before updating tail */
1021
1022 info->tail = tail;
1023 ring->tail = tail;
1024
Cong Wange8e3c3d2011-11-25 23:14:27 +08001025 put_aio_ring_event(event);
1026 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
1028 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001029
1030 /*
1031 * Check if the user asked us to deliver the result through an
1032 * eventfd. The eventfd_signal() function is safe to be called
1033 * from IRQ context.
1034 */
Davide Libenzi87c3a862009-03-18 17:04:19 -07001035 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001036 eventfd_signal(iocb->ki_eventfd, 1);
1037
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038put_rq:
1039 /* everything turned out well, dispose of the aiocb. */
1040 ret = __aio_put_req(ctx, iocb);
1041
Quentin Barnes6cb2a212008-03-19 17:00:39 -07001042 /*
1043 * We have to order our ring_info tail store above and test
1044 * of the wait list below outside the wait lock. This is
1045 * like in wake_up_bit() where clearing a bit has to be
1046 * ordered with the unlocked test.
1047 */
1048 smp_mb();
1049
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050 if (waitqueue_active(&ctx->wait))
1051 wake_up(&ctx->wait);
1052
Ken Chendee11c22007-02-03 01:13:45 -08001053 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 return ret;
1055}
H Hartley Sweeten385773e2009-09-22 16:43:53 -07001056EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057
1058/* aio_read_evt
1059 * Pull an event off of the ioctx's event ring. Returns the number of
1060 * events fetched (0 or 1 ;-)
1061 * FIXME: make this use cmpxchg.
1062 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1063 */
1064static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1065{
1066 struct aio_ring_info *info = &ioctx->ring_info;
1067 struct aio_ring *ring;
1068 unsigned long head;
1069 int ret = 0;
1070
Cong Wange8e3c3d2011-11-25 23:14:27 +08001071 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1073 (unsigned long)ring->head, (unsigned long)ring->tail,
1074 (unsigned long)ring->nr);
1075
1076 if (ring->head == ring->tail)
1077 goto out;
1078
1079 spin_lock(&info->ring_lock);
1080
1081 head = ring->head % info->nr;
1082 if (head != ring->tail) {
Cong Wange8e3c3d2011-11-25 23:14:27 +08001083 struct io_event *evp = aio_ring_event(info, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 *ent = *evp;
1085 head = (head + 1) % info->nr;
1086 smp_mb(); /* finish reading the event before updatng the head */
1087 ring->head = head;
1088 ret = 1;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001089 put_aio_ring_event(evp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 }
1091 spin_unlock(&info->ring_lock);
1092
1093out:
Cong Wange8e3c3d2011-11-25 23:14:27 +08001094 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1096 (unsigned long)ring->head, (unsigned long)ring->tail);
1097 return ret;
1098}
1099
1100struct aio_timeout {
1101 struct timer_list timer;
1102 int timed_out;
1103 struct task_struct *p;
1104};
1105
1106static void timeout_func(unsigned long data)
1107{
1108 struct aio_timeout *to = (struct aio_timeout *)data;
1109
1110 to->timed_out = 1;
1111 wake_up_process(to->p);
1112}
1113
1114static inline void init_timeout(struct aio_timeout *to)
1115{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001116 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 to->timed_out = 0;
1118 to->p = current;
1119}
1120
1121static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1122 const struct timespec *ts)
1123{
1124 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1125 if (time_after(to->timer.expires, jiffies))
1126 add_timer(&to->timer);
1127 else
1128 to->timed_out = 1;
1129}
1130
1131static inline void clear_timeout(struct aio_timeout *to)
1132{
1133 del_singleshot_timer_sync(&to->timer);
1134}
1135
1136static int read_events(struct kioctx *ctx,
1137 long min_nr, long nr,
1138 struct io_event __user *event,
1139 struct timespec __user *timeout)
1140{
1141 long start_jiffies = jiffies;
1142 struct task_struct *tsk = current;
1143 DECLARE_WAITQUEUE(wait, tsk);
1144 int ret;
1145 int i = 0;
1146 struct io_event ent;
1147 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 int retry = 0;
1149
1150 /* needed to zero any padding within an entry (there shouldn't be
1151 * any, but C is fun!
1152 */
1153 memset(&ent, 0, sizeof(ent));
1154retry:
1155 ret = 0;
1156 while (likely(i < nr)) {
1157 ret = aio_read_evt(ctx, &ent);
1158 if (unlikely(ret <= 0))
1159 break;
1160
1161 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1162 ent.data, ent.obj, ent.res, ent.res2);
1163
1164 /* Could we split the check in two? */
1165 ret = -EFAULT;
1166 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1167 dprintk("aio: lost an event due to EFAULT.\n");
1168 break;
1169 }
1170 ret = 0;
1171
1172 /* Good, event copied to userland, update counts. */
1173 event ++;
1174 i ++;
1175 }
1176
1177 if (min_nr <= i)
1178 return i;
1179 if (ret)
1180 return ret;
1181
1182 /* End fast path */
1183
1184 /* racey check, but it gets redone */
1185 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1186 retry = 1;
1187 aio_run_all_iocbs(ctx);
1188 goto retry;
1189 }
1190
1191 init_timeout(&to);
1192 if (timeout) {
1193 struct timespec ts;
1194 ret = -EFAULT;
1195 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1196 goto out;
1197
1198 set_timeout(start_jiffies, &to, &ts);
1199 }
1200
1201 while (likely(i < nr)) {
1202 add_wait_queue_exclusive(&ctx->wait, &wait);
1203 do {
1204 set_task_state(tsk, TASK_INTERRUPTIBLE);
1205 ret = aio_read_evt(ctx, &ent);
1206 if (ret)
1207 break;
1208 if (min_nr <= i)
1209 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001210 if (unlikely(ctx->dead)) {
1211 ret = -EINVAL;
1212 break;
1213 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 if (to.timed_out) /* Only check after read evt */
1215 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001216 /* Try to only show up in io wait if there are ops
1217 * in flight */
1218 if (ctx->reqs_active)
1219 io_schedule();
1220 else
1221 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 if (signal_pending(tsk)) {
1223 ret = -EINTR;
1224 break;
1225 }
1226 /*ret = aio_read_evt(ctx, &ent);*/
1227 } while (1) ;
1228
1229 set_task_state(tsk, TASK_RUNNING);
1230 remove_wait_queue(&ctx->wait, &wait);
1231
1232 if (unlikely(ret <= 0))
1233 break;
1234
1235 ret = -EFAULT;
1236 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1237 dprintk("aio: lost an event due to EFAULT.\n");
1238 break;
1239 }
1240
1241 /* Good, event copied to userland, update counts. */
1242 event ++;
1243 i ++;
1244 }
1245
1246 if (timeout)
1247 clear_timeout(&to);
1248out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001249 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 return i ? i : ret;
1251}
1252
1253/* Take an ioctx and remove it from the list of ioctx's. Protects
1254 * against races with itself via ->dead.
1255 */
1256static void io_destroy(struct kioctx *ioctx)
1257{
1258 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 int was_dead;
1260
1261 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001262 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 was_dead = ioctx->dead;
1264 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001265 hlist_del_rcu(&ioctx->list);
1266 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267
1268 dprintk("aio_release(%p)\n", ioctx);
1269 if (likely(!was_dead))
1270 put_ioctx(ioctx); /* twice for the list */
1271
1272 aio_cancel_all(ioctx);
1273 wait_for_all_aios(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001274
1275 /*
1276 * Wake up any waiters. The setting of ctx->dead must be seen
1277 * by other CPUs at this point. Right now, we rely on the
1278 * locking done by the above calls to ensure this consistency.
1279 */
Roland Dreiere91f90b2011-03-22 16:35:10 -07001280 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 put_ioctx(ioctx); /* once for the lookup */
1282}
1283
1284/* sys_io_setup:
1285 * Create an aio_context capable of receiving at least nr_events.
1286 * ctxp must not point to an aio_context that already exists, and
1287 * must be initialized to 0 prior to the call. On successful
1288 * creation of the aio_context, *ctxp is filled in with the resulting
1289 * handle. May fail with -EINVAL if *ctxp is not initialized,
1290 * if the specified nr_events exceeds internal limits. May fail
1291 * with -EAGAIN if the specified nr_events exceeds the user's limit
1292 * of available events. May fail with -ENOMEM if insufficient kernel
1293 * resources are available. May fail with -EFAULT if an invalid
1294 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1295 * implemented.
1296 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001297SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298{
1299 struct kioctx *ioctx = NULL;
1300 unsigned long ctx;
1301 long ret;
1302
1303 ret = get_user(ctx, ctxp);
1304 if (unlikely(ret))
1305 goto out;
1306
1307 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001308 if (unlikely(ctx || nr_events == 0)) {
1309 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1310 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 goto out;
1312 }
1313
1314 ioctx = ioctx_alloc(nr_events);
1315 ret = PTR_ERR(ioctx);
1316 if (!IS_ERR(ioctx)) {
1317 ret = put_user(ioctx->user_id, ctxp);
Al Viro86b62a22012-03-07 05:16:35 +00001318 if (!ret) {
1319 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320 return 0;
Al Viro86b62a22012-03-07 05:16:35 +00001321 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 io_destroy(ioctx);
1323 }
1324
1325out:
1326 return ret;
1327}
1328
1329/* sys_io_destroy:
1330 * Destroy the aio_context specified. May cancel any outstanding
1331 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001332 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 * is invalid.
1334 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001335SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336{
1337 struct kioctx *ioctx = lookup_ioctx(ctx);
1338 if (likely(NULL != ioctx)) {
1339 io_destroy(ioctx);
1340 return 0;
1341 }
1342 pr_debug("EINVAL: io_destroy: invalid context id\n");
1343 return -EINVAL;
1344}
1345
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001346static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1347{
1348 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1349
1350 BUG_ON(ret <= 0);
1351
1352 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1353 ssize_t this = min((ssize_t)iov->iov_len, ret);
1354 iov->iov_base += this;
1355 iov->iov_len -= this;
1356 iocb->ki_left -= this;
1357 ret -= this;
1358 if (iov->iov_len == 0) {
1359 iocb->ki_cur_seg++;
1360 iov++;
1361 }
1362 }
1363
1364 /* the caller should not have done more io than what fit in
1365 * the remaining iovecs */
1366 BUG_ON(ret > 0 && iocb->ki_left == 0);
1367}
1368
1369static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370{
1371 struct file *file = iocb->ki_filp;
1372 struct address_space *mapping = file->f_mapping;
1373 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001374 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1375 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001377 unsigned short opcode;
1378
1379 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1380 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1381 rw_op = file->f_op->aio_read;
1382 opcode = IOCB_CMD_PREADV;
1383 } else {
1384 rw_op = file->f_op->aio_write;
1385 opcode = IOCB_CMD_PWRITEV;
1386 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387
Rusty Russellc2ec6682008-02-08 04:20:15 -08001388 /* This matches the pread()/pwrite() logic */
1389 if (iocb->ki_pos < 0)
1390 return -EINVAL;
1391
Zach Brown897f15f2005-09-30 11:58:55 -07001392 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001393 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1394 iocb->ki_nr_segs - iocb->ki_cur_seg,
1395 iocb->ki_pos);
1396 if (ret > 0)
1397 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001398
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001399 /* retry all partial writes. retry partial reads as long as its a
1400 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001401 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001402 (opcode == IOCB_CMD_PWRITEV ||
1403 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
1405 /* This means we must have transferred all that we could */
1406 /* No need to retry anymore */
1407 if ((ret == 0) || (iocb->ki_left == 0))
1408 ret = iocb->ki_nbytes - iocb->ki_left;
1409
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001410 /* If we managed to write some out we return that, rather than
1411 * the eventual error. */
1412 if (opcode == IOCB_CMD_PWRITEV
1413 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1414 && iocb->ki_nbytes - iocb->ki_left)
1415 ret = iocb->ki_nbytes - iocb->ki_left;
1416
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 return ret;
1418}
1419
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420static ssize_t aio_fdsync(struct kiocb *iocb)
1421{
1422 struct file *file = iocb->ki_filp;
1423 ssize_t ret = -EINVAL;
1424
1425 if (file->f_op->aio_fsync)
1426 ret = file->f_op->aio_fsync(iocb, 1);
1427 return ret;
1428}
1429
1430static ssize_t aio_fsync(struct kiocb *iocb)
1431{
1432 struct file *file = iocb->ki_filp;
1433 ssize_t ret = -EINVAL;
1434
1435 if (file->f_op->aio_fsync)
1436 ret = file->f_op->aio_fsync(iocb, 0);
1437 return ret;
1438}
1439
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001440static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001441{
1442 ssize_t ret;
1443
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001444#ifdef CONFIG_COMPAT
1445 if (compat)
1446 ret = compat_rw_copy_check_uvector(type,
1447 (struct compat_iovec __user *)kiocb->ki_buf,
1448 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001449 &kiocb->ki_iovec, 1);
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001450 else
1451#endif
1452 ret = rw_copy_check_uvector(type,
1453 (struct iovec __user *)kiocb->ki_buf,
1454 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001455 &kiocb->ki_iovec, 1);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001456 if (ret < 0)
1457 goto out;
1458
1459 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1460 kiocb->ki_cur_seg = 0;
1461 /* ki_nbytes/left now reflect bytes instead of segs */
1462 kiocb->ki_nbytes = ret;
1463 kiocb->ki_left = ret;
1464
1465 ret = 0;
1466out:
1467 return ret;
1468}
1469
1470static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1471{
1472 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1473 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1474 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1475 kiocb->ki_nr_segs = 1;
1476 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001477 return 0;
1478}
1479
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480/*
1481 * aio_setup_iocb:
1482 * Performs the initial checks and aio retry method
1483 * setup for the kiocb at the time of io submission.
1484 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001485static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486{
1487 struct file *file = kiocb->ki_filp;
1488 ssize_t ret = 0;
1489
1490 switch (kiocb->ki_opcode) {
1491 case IOCB_CMD_PREAD:
1492 ret = -EBADF;
1493 if (unlikely(!(file->f_mode & FMODE_READ)))
1494 break;
1495 ret = -EFAULT;
1496 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1497 kiocb->ki_left)))
1498 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001499 ret = security_file_permission(file, MAY_READ);
1500 if (unlikely(ret))
1501 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001502 ret = aio_setup_single_vector(kiocb);
1503 if (ret)
1504 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 ret = -EINVAL;
1506 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001507 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 break;
1509 case IOCB_CMD_PWRITE:
1510 ret = -EBADF;
1511 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1512 break;
1513 ret = -EFAULT;
1514 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1515 kiocb->ki_left)))
1516 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001517 ret = security_file_permission(file, MAY_WRITE);
1518 if (unlikely(ret))
1519 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001520 ret = aio_setup_single_vector(kiocb);
1521 if (ret)
1522 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 ret = -EINVAL;
1524 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001525 kiocb->ki_retry = aio_rw_vect_retry;
1526 break;
1527 case IOCB_CMD_PREADV:
1528 ret = -EBADF;
1529 if (unlikely(!(file->f_mode & FMODE_READ)))
1530 break;
1531 ret = security_file_permission(file, MAY_READ);
1532 if (unlikely(ret))
1533 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001534 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001535 if (ret)
1536 break;
1537 ret = -EINVAL;
1538 if (file->f_op->aio_read)
1539 kiocb->ki_retry = aio_rw_vect_retry;
1540 break;
1541 case IOCB_CMD_PWRITEV:
1542 ret = -EBADF;
1543 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1544 break;
1545 ret = security_file_permission(file, MAY_WRITE);
1546 if (unlikely(ret))
1547 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001548 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001549 if (ret)
1550 break;
1551 ret = -EINVAL;
1552 if (file->f_op->aio_write)
1553 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 break;
1555 case IOCB_CMD_FDSYNC:
1556 ret = -EINVAL;
1557 if (file->f_op->aio_fsync)
1558 kiocb->ki_retry = aio_fdsync;
1559 break;
1560 case IOCB_CMD_FSYNC:
1561 ret = -EINVAL;
1562 if (file->f_op->aio_fsync)
1563 kiocb->ki_retry = aio_fsync;
1564 break;
1565 default:
1566 dprintk("EINVAL: io_submit: no operation provided\n");
1567 ret = -EINVAL;
1568 }
1569
1570 if (!kiocb->ki_retry)
1571 return ret;
1572
1573 return 0;
1574}
1575
Adrian Bunkd5470b52008-04-29 00:58:57 -07001576static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer080d6762011-11-02 13:40:10 -07001577 struct iocb *iocb, struct kiocb_batch *batch,
1578 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579{
1580 struct kiocb *req;
1581 struct file *file;
1582 ssize_t ret;
1583
1584 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001585 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 pr_debug("EINVAL: io_submit: reserve field set\n");
1587 return -EINVAL;
1588 }
1589
1590 /* prevent overflows */
1591 if (unlikely(
1592 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1593 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1594 ((ssize_t)iocb->aio_nbytes < 0)
1595 )) {
1596 pr_debug("EINVAL: io_submit: overflow check\n");
1597 return -EINVAL;
1598 }
1599
1600 file = fget(iocb->aio_fildes);
1601 if (unlikely(!file))
1602 return -EBADF;
1603
Jeff Moyer080d6762011-11-02 13:40:10 -07001604 req = aio_get_req(ctx, batch); /* returns with 2 references to req */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 if (unlikely(!req)) {
1606 fput(file);
1607 return -EAGAIN;
1608 }
Yan Zheng87e28312007-10-08 12:16:20 -07001609 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001610 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1611 /*
1612 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1613 * instance of the file* now. The file descriptor must be
1614 * an eventfd() fd, and will be signaled for each completed
1615 * event using the eventfd_signal() function.
1616 */
Davide Libenzi13389012009-06-30 11:41:11 -07001617 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001618 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001619 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001620 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001621 goto out_put_req;
1622 }
1623 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624
Ken Chen212079c2005-05-01 08:59:15 -07001625 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 if (unlikely(ret)) {
1627 dprintk("EFAULT: aio_key\n");
1628 goto out_put_req;
1629 }
1630
1631 req->ki_obj.user = user_iocb;
1632 req->ki_user_data = iocb->aio_data;
1633 req->ki_pos = iocb->aio_offset;
1634
1635 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1636 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1637 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001639 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640
1641 if (ret)
1642 goto out_put_req;
1643
1644 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001645 /*
1646 * We could have raced with io_destroy() and are currently holding a
1647 * reference to ctx which should be destroyed. We cannot submit IO
1648 * since ctx gets freed as soon as io_submit() puts its reference. The
1649 * check here is reliable: io_destroy() sets ctx->dead before waiting
1650 * for outstanding IO and the barrier between these two is realized by
1651 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1652 * increment ctx->reqs_active before checking for ctx->dead and the
1653 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1654 * don't see ctx->dead set here, io_destroy() waits for our IO to
1655 * finish.
1656 */
1657 if (ctx->dead) {
1658 spin_unlock_irq(&ctx->ctx_lock);
1659 ret = -EINVAL;
1660 goto out_put_req;
1661 }
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001662 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001663 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001664 /* drain the run list */
1665 while (__aio_run_iocbs(ctx))
1666 ;
1667 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001669
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 aio_put_req(req); /* drop extra ref to req */
1671 return 0;
1672
1673out_put_req:
1674 aio_put_req(req); /* drop extra ref to req */
1675 aio_put_req(req); /* drop i/o ref to req */
1676 return ret;
1677}
1678
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001679long do_io_submit(aio_context_t ctx_id, long nr,
1680 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681{
1682 struct kioctx *ctx;
1683 long ret = 0;
Jeff Moyer080d6762011-11-02 13:40:10 -07001684 int i = 0;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001685 struct blk_plug plug;
Jeff Moyer080d6762011-11-02 13:40:10 -07001686 struct kiocb_batch batch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687
1688 if (unlikely(nr < 0))
1689 return -EINVAL;
1690
Jeff Moyer75e1c702010-09-10 14:16:00 -07001691 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1692 nr = LONG_MAX/sizeof(*iocbpp);
1693
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1695 return -EFAULT;
1696
1697 ctx = lookup_ioctx(ctx_id);
1698 if (unlikely(!ctx)) {
1699 pr_debug("EINVAL: io_submit: invalid context id\n");
1700 return -EINVAL;
1701 }
1702
Jeff Moyer080d6762011-11-02 13:40:10 -07001703 kiocb_batch_init(&batch, nr);
1704
Shaohua Li9f5b9422010-07-01 07:55:01 +02001705 blk_start_plug(&plug);
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 /*
1708 * AKPM: should this return a partial result if some of the IOs were
1709 * successfully submitted?
1710 */
1711 for (i=0; i<nr; i++) {
1712 struct iocb __user *user_iocb;
1713 struct iocb tmp;
1714
1715 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1716 ret = -EFAULT;
1717 break;
1718 }
1719
1720 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1721 ret = -EFAULT;
1722 break;
1723 }
1724
Jeff Moyer080d6762011-11-02 13:40:10 -07001725 ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 if (ret)
1727 break;
1728 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001729 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
Gleb Natapov69e47472012-01-08 17:07:28 +02001731 kiocb_batch_free(ctx, &batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 put_ioctx(ctx);
1733 return i ? i : ret;
1734}
1735
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001736/* sys_io_submit:
1737 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1738 * the number of iocbs queued. May return -EINVAL if the aio_context
1739 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1740 * *iocbpp[0] is not properly initialized, if the operation specified
1741 * is invalid for the file descriptor in the iocb. May fail with
1742 * -EFAULT if any of the data structures point to invalid data. May
1743 * fail with -EBADF if the file descriptor specified in the first
1744 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1745 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1746 * fail with -ENOSYS if not implemented.
1747 */
1748SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1749 struct iocb __user * __user *, iocbpp)
1750{
1751 return do_io_submit(ctx_id, nr, iocbpp, 0);
1752}
1753
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754/* lookup_kiocb
1755 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001757static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1758 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759{
1760 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001761
1762 assert_spin_locked(&ctx->ctx_lock);
1763
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 /* TODO: use a hash or array, this sucks. */
1765 list_for_each(pos, &ctx->active_reqs) {
1766 struct kiocb *kiocb = list_kiocb(pos);
1767 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1768 return kiocb;
1769 }
1770 return NULL;
1771}
1772
1773/* sys_io_cancel:
1774 * Attempts to cancel an iocb previously passed to io_submit. If
1775 * the operation is successfully cancelled, the resulting event is
1776 * copied into the memory pointed to by result without being placed
1777 * into the completion queue and 0 is returned. May fail with
1778 * -EFAULT if any of the data structures pointed to are invalid.
1779 * May fail with -EINVAL if aio_context specified by ctx_id is
1780 * invalid. May fail with -EAGAIN if the iocb specified was not
1781 * cancelled. Will fail with -ENOSYS if not implemented.
1782 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001783SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1784 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785{
1786 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1787 struct kioctx *ctx;
1788 struct kiocb *kiocb;
1789 u32 key;
1790 int ret;
1791
1792 ret = get_user(key, &iocb->aio_key);
1793 if (unlikely(ret))
1794 return -EFAULT;
1795
1796 ctx = lookup_ioctx(ctx_id);
1797 if (unlikely(!ctx))
1798 return -EINVAL;
1799
1800 spin_lock_irq(&ctx->ctx_lock);
1801 ret = -EAGAIN;
1802 kiocb = lookup_kiocb(ctx, iocb, key);
1803 if (kiocb && kiocb->ki_cancel) {
1804 cancel = kiocb->ki_cancel;
1805 kiocb->ki_users ++;
1806 kiocbSetCancelled(kiocb);
1807 } else
1808 cancel = NULL;
1809 spin_unlock_irq(&ctx->ctx_lock);
1810
1811 if (NULL != cancel) {
1812 struct io_event tmp;
1813 pr_debug("calling cancel\n");
1814 memset(&tmp, 0, sizeof(tmp));
1815 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1816 tmp.data = kiocb->ki_user_data;
1817 ret = cancel(kiocb, &tmp);
1818 if (!ret) {
1819 /* Cancellation succeeded -- copy the result
1820 * into the user's buffer.
1821 */
1822 if (copy_to_user(result, &tmp, sizeof(tmp)))
1823 ret = -EFAULT;
1824 }
1825 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001826 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827
1828 put_ioctx(ctx);
1829
1830 return ret;
1831}
1832
1833/* io_getevents:
1834 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001835 * the completion queue for the aio_context specified by ctx_id. If
1836 * it succeeds, the number of read events is returned. May fail with
1837 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1838 * out of range, if timeout is out of range. May fail with -EFAULT
1839 * if any of the memory specified is invalid. May return 0 or
1840 * < min_nr if the timeout specified by timeout has elapsed
1841 * before sufficient events are available, where timeout == NULL
1842 * specifies an infinite timeout. Note that the timeout pointed to by
1843 * timeout is relative and will be updated if not NULL and the
1844 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001846SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1847 long, min_nr,
1848 long, nr,
1849 struct io_event __user *, events,
1850 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851{
1852 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1853 long ret = -EINVAL;
1854
1855 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001856 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 ret = read_events(ioctx, min_nr, nr, events, timeout);
1858 put_ioctx(ioctx);
1859 }
1860
Roland McGrath598af052008-04-10 15:38:45 -07001861 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862 return ret;
1863}