blob: da887604dfc51929cd4cc17b10a943645b4618ef [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
Al Viro06af1212012-03-20 16:26:24 -0400308/* kill_ctx
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 * 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 */
Al Viro06af1212012-03-20 16:26:24 -0400313static void kill_ctx(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314{
315 int (*cancel)(struct kiocb *, struct io_event *);
Al Viro06af1212012-03-20 16:26:24 -0400316 struct task_struct *tsk = current;
317 DECLARE_WAITQUEUE(wait, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 struct io_event res;
Al Viro06af1212012-03-20 16:26:24 -0400319
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 spin_lock_irq(&ctx->ctx_lock);
321 ctx->dead = 1;
322 while (!list_empty(&ctx->active_reqs)) {
323 struct list_head *pos = ctx->active_reqs.next;
324 struct kiocb *iocb = list_kiocb(pos);
325 list_del_init(&iocb->ki_list);
326 cancel = iocb->ki_cancel;
327 kiocbSetCancelled(iocb);
328 if (cancel) {
329 iocb->ki_users++;
330 spin_unlock_irq(&ctx->ctx_lock);
331 cancel(iocb, &res);
332 spin_lock_irq(&ctx->ctx_lock);
333 }
334 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800337 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 add_wait_queue(&ctx->wait, &wait);
340 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
341 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800342 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700343 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800345 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 }
347 __set_task_state(tsk, TASK_RUNNING);
348 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800349
350out:
351 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352}
353
354/* wait_on_sync_kiocb:
355 * Waits on the given sync kiocb to complete.
356 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800357ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358{
359 while (iocb->ki_users) {
360 set_current_state(TASK_UNINTERRUPTIBLE);
361 if (!iocb->ki_users)
362 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700363 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 }
365 __set_current_state(TASK_RUNNING);
366 return iocb->ki_user_data;
367}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700368EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
370/* exit_aio: called when the last user of mm goes away. At this point,
371 * there is no way for any new requests to be submited or any of the
372 * io_* syscalls to be called on the context. However, there may be
373 * outstanding requests which hold references to the context; as they
374 * go away, they will call put_ioctx and release any pinned memory
375 * associated with the request (held via struct page * references).
376 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800377void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
Jens Axboeabf137d2008-12-09 08:11:22 +0100379 struct kioctx *ctx;
380
381 while (!hlist_empty(&mm->ioctx_list)) {
382 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
383 hlist_del_rcu(&ctx->list);
384
Al Viro06af1212012-03-20 16:26:24 -0400385 kill_ctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386
387 if (1 != atomic_read(&ctx->users))
388 printk(KERN_DEBUG
389 "exit_aio:ioctx still alive: %d %d %d\n",
390 atomic_read(&ctx->users), ctx->dead,
391 ctx->reqs_active);
392 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 }
394}
395
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396/* aio_get_req
397 * Allocate a slot for an aio request. Increments the users count
398 * of the kioctx so that the kioctx stays around until all requests are
399 * complete. Returns NULL if no requests are free.
400 *
401 * Returns with kiocb->users set to 2. The io submit code path holds
402 * an extra reference while submitting the i/o.
403 * This prevents races between the aio code path referencing the
404 * req (after submitting it) and aio_complete() freeing the req.
405 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800406static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407{
408 struct kiocb *req = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
410 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
411 if (unlikely(!req))
412 return NULL;
413
Zach Brown4faa5282005-10-17 16:43:33 -0700414 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 req->ki_users = 2;
416 req->ki_key = 0;
417 req->ki_ctx = ctx;
418 req->ki_cancel = NULL;
419 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 req->ki_dtor = NULL;
421 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700422 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700424 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 return req;
427}
428
Jeff Moyer080d6762011-11-02 13:40:10 -0700429/*
430 * struct kiocb's are allocated in batches to reduce the number of
431 * times the ctx lock is acquired and released.
432 */
433#define KIOCB_BATCH_SIZE 32L
434struct kiocb_batch {
435 struct list_head head;
436 long count; /* number of requests left to allocate */
437};
438
439static void kiocb_batch_init(struct kiocb_batch *batch, long total)
440{
441 INIT_LIST_HEAD(&batch->head);
442 batch->count = total;
443}
444
Gleb Natapov69e47472012-01-08 17:07:28 +0200445static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
Jeff Moyer080d6762011-11-02 13:40:10 -0700446{
447 struct kiocb *req, *n;
448
Gleb Natapov69e47472012-01-08 17:07:28 +0200449 if (list_empty(&batch->head))
450 return;
451
452 spin_lock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700453 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
454 list_del(&req->ki_batch);
Gleb Natapov69e47472012-01-08 17:07:28 +0200455 list_del(&req->ki_list);
Jeff Moyer080d6762011-11-02 13:40:10 -0700456 kmem_cache_free(kiocb_cachep, req);
Gleb Natapov69e47472012-01-08 17:07:28 +0200457 ctx->reqs_active--;
Jeff Moyer080d6762011-11-02 13:40:10 -0700458 }
Jeff Moyer880641b2012-03-05 14:59:12 -0800459 if (unlikely(!ctx->reqs_active && ctx->dead))
460 wake_up_all(&ctx->wait);
Gleb Natapov69e47472012-01-08 17:07:28 +0200461 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700462}
463
464/*
465 * Allocate a batch of kiocbs. This avoids taking and dropping the
466 * context lock a lot during setup.
467 */
468static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
469{
470 unsigned short allocated, to_alloc;
471 long avail;
472 bool called_fput = false;
473 struct kiocb *req, *n;
474 struct aio_ring *ring;
475
476 to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
477 for (allocated = 0; allocated < to_alloc; allocated++) {
478 req = __aio_get_req(ctx);
479 if (!req)
480 /* allocation failed, go with what we've got */
481 break;
482 list_add(&req->ki_batch, &batch->head);
483 }
484
485 if (allocated == 0)
486 goto out;
487
488retry:
489 spin_lock_irq(&ctx->ctx_lock);
490 ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
491
492 avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active;
493 BUG_ON(avail < 0);
494 if (avail == 0 && !called_fput) {
495 /*
496 * Handle a potential starvation case. It is possible that
497 * we hold the last reference on a struct file, causing us
498 * to delay the final fput to non-irq context. In this case,
499 * ctx->reqs_active is artificially high. Calling the fput
500 * routine here may free up a slot in the event completion
501 * ring, allowing this allocation to succeed.
502 */
503 kunmap_atomic(ring);
504 spin_unlock_irq(&ctx->ctx_lock);
505 aio_fput_routine(NULL);
506 called_fput = true;
507 goto retry;
508 }
509
510 if (avail < allocated) {
511 /* Trim back the number of requests. */
512 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
513 list_del(&req->ki_batch);
514 kmem_cache_free(kiocb_cachep, req);
515 if (--allocated <= avail)
516 break;
517 }
518 }
519
520 batch->count -= allocated;
521 list_for_each_entry(req, &batch->head, ki_batch) {
522 list_add(&req->ki_list, &ctx->active_reqs);
523 ctx->reqs_active++;
524 }
525
526 kunmap_atomic(ring);
527 spin_unlock_irq(&ctx->ctx_lock);
528
529out:
530 return allocated;
531}
532
533static inline struct kiocb *aio_get_req(struct kioctx *ctx,
534 struct kiocb_batch *batch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
536 struct kiocb *req;
Jeff Moyer080d6762011-11-02 13:40:10 -0700537
538 if (list_empty(&batch->head))
539 if (kiocb_batch_refill(ctx, batch) == 0)
540 return NULL;
541 req = list_first_entry(&batch->head, struct kiocb, ki_batch);
542 list_del(&req->ki_batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 return req;
544}
545
546static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
547{
Zach Brownd00689a2005-11-13 16:07:34 -0800548 assert_spin_locked(&ctx->ctx_lock);
549
Davide Libenzi13389012009-06-30 11:41:11 -0700550 if (req->ki_eventfd != NULL)
551 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 if (req->ki_dtor)
553 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700554 if (req->ki_iovec != &req->ki_inline_vec)
555 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 kmem_cache_free(kiocb_cachep, req);
557 ctx->reqs_active--;
558
559 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700560 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561}
562
David Howells65f27f32006-11-22 14:55:48 +0000563static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564{
565 spin_lock_irq(&fput_lock);
566 while (likely(!list_empty(&fput_head))) {
567 struct kiocb *req = list_kiocb(fput_head.next);
568 struct kioctx *ctx = req->ki_ctx;
569
570 list_del(&req->ki_list);
571 spin_unlock_irq(&fput_lock);
572
Davide Libenzi87c3a862009-03-18 17:04:19 -0700573 /* Complete the fput(s) */
574 if (req->ki_filp != NULL)
Al Virod7065da2010-05-26 15:13:55 -0400575 fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576
577 /* Link the iocb into the context's free list */
Al Viroc7b28552012-03-08 17:51:19 +0000578 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 spin_lock_irq(&ctx->ctx_lock);
580 really_put_req(ctx, req);
Al Viroc7b28552012-03-08 17:51:19 +0000581 /*
582 * at that point ctx might've been killed, but actual
583 * freeing is RCU'd
584 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 spin_unlock_irq(&ctx->ctx_lock);
Al Viroc7b28552012-03-08 17:51:19 +0000586 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 spin_lock_irq(&fput_lock);
589 }
590 spin_unlock_irq(&fput_lock);
591}
592
593/* __aio_put_req
594 * Returns true if this put was the last user of the request.
595 */
596static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
597{
Al Viro516e0cc2008-07-26 00:39:17 -0400598 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
599 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600
Zach Brownd00689a2005-11-13 16:07:34 -0800601 assert_spin_locked(&ctx->ctx_lock);
602
Davide Libenzi87c3a862009-03-18 17:04:19 -0700603 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100604 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 if (likely(req->ki_users))
606 return 0;
607 list_del(&req->ki_list); /* remove from active_reqs */
608 req->ki_cancel = NULL;
609 req->ki_retry = NULL;
610
Davide Libenzi87c3a862009-03-18 17:04:19 -0700611 /*
612 * Try to optimize the aio and eventfd file* puts, by avoiding to
Al Virod7065da2010-05-26 15:13:55 -0400613 * schedule work in case it is not final fput() time. In normal cases,
Davide Libenzi87c3a862009-03-18 17:04:19 -0700614 * we would not be holding the last reference to the file*, so
615 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 */
Al Virod7065da2010-05-26 15:13:55 -0400617 if (unlikely(!fput_atomic(req->ki_filp))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 spin_lock(&fput_lock);
619 list_add(&req->ki_list, &fput_head);
620 spin_unlock(&fput_lock);
Tejun Heod37adaa2011-01-26 17:42:27 +0100621 schedule_work(&fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700622 } else {
623 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700625 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 return 1;
627}
628
629/* aio_put_req
630 * Returns true if this put was the last user of the kiocb,
631 * false if the request is still in use.
632 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800633int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634{
635 struct kioctx *ctx = req->ki_ctx;
636 int ret;
637 spin_lock_irq(&ctx->ctx_lock);
638 ret = __aio_put_req(ctx, req);
639 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 return ret;
641}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700642EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
Adrian Bunkd5470b52008-04-29 00:58:57 -0700644static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645{
Jens Axboeabf137d2008-12-09 08:11:22 +0100646 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700647 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100648 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649
Jens Axboeabf137d2008-12-09 08:11:22 +0100650 rcu_read_lock();
651
652 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800653 /*
654 * RCU protects us against accessing freed memory but
655 * we have to be careful not to get a reference when the
656 * reference count already dropped to 0 (ctx->dead test
657 * is unreliable because of races).
658 */
659 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700660 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 break;
662 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100663 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
Jens Axboeabf137d2008-12-09 08:11:22 +0100665 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700666 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667}
668
669/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 * Queue up a kiocb to be retried. Assumes that the kiocb
671 * has already been marked as kicked, and places it on
672 * the retry run list for the corresponding ioctx, if it
673 * isn't already queued. Returns 1 if it actually queued
674 * the kiocb (to tell the caller to activate the work
675 * queue to process it), or 0, if it found that it was
676 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 */
678static inline int __queue_kicked_iocb(struct kiocb *iocb)
679{
680 struct kioctx *ctx = iocb->ki_ctx;
681
Zach Brownd00689a2005-11-13 16:07:34 -0800682 assert_spin_locked(&ctx->ctx_lock);
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 if (list_empty(&iocb->ki_run_list)) {
685 list_add_tail(&iocb->ki_run_list,
686 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 return 1;
688 }
689 return 0;
690}
691
692/* aio_run_iocb
693 * This is the core aio execution routine. It is
694 * invoked both for initial i/o submission and
695 * subsequent retries via the aio_kick_handler.
696 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200697 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 * as needed during processing.
699 *
700 * Calls the iocb retry method (already setup for the
701 * iocb on initial submission) for operation specific
702 * handling, but takes care of most of common retry
703 * execution details for a given iocb. The retry method
704 * needs to be non-blocking as far as possible, to avoid
705 * holding up other iocbs waiting to be serviced by the
706 * retry kernel thread.
707 *
708 * The trickier parts in this code have to do with
709 * ensuring that only one retry instance is in progress
710 * for a given iocb at any time. Providing that guarantee
711 * simplifies the coding of individual aio operations as
712 * it avoids various potential races.
713 */
714static ssize_t aio_run_iocb(struct kiocb *iocb)
715{
716 struct kioctx *ctx = iocb->ki_ctx;
717 ssize_t (*retry)(struct kiocb *);
718 ssize_t ret;
719
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 if (!(retry = iocb->ki_retry)) {
721 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
722 return 0;
723 }
724
725 /*
726 * We don't want the next retry iteration for this
727 * operation to start until this one has returned and
728 * updated the iocb state. However, wait_queue functions
729 * can trigger a kick_iocb from interrupt context in the
730 * meantime, indicating that data is available for the next
731 * iteration. We want to remember that and enable the
732 * next retry iteration _after_ we are through with
733 * this one.
734 *
735 * So, in order to be able to register a "kick", but
736 * prevent it from being queued now, we clear the kick
737 * flag, but make the kick code *think* that the iocb is
738 * still on the run list until we are actually done.
739 * When we are done with this iteration, we check if
740 * the iocb was kicked in the meantime and if so, queue
741 * it up afresh.
742 */
743
744 kiocbClearKicked(iocb);
745
746 /*
747 * This is so that aio_complete knows it doesn't need to
748 * pull the iocb off the run list (We can't just call
749 * INIT_LIST_HEAD because we don't want a kick_iocb to
750 * queue this on the run list yet)
751 */
752 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
753 spin_unlock_irq(&ctx->ctx_lock);
754
755 /* Quit retrying if the i/o has been cancelled */
756 if (kiocbIsCancelled(iocb)) {
757 ret = -EINTR;
758 aio_complete(iocb, ret, 0);
759 /* must not access the iocb after this */
760 goto out;
761 }
762
763 /*
764 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700765 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Jan Karaa0c42ba2010-09-22 13:05:03 -0700769 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
770 /*
771 * There's no easy way to restart the syscall since other AIO's
772 * may be already running. Just fail this IO with EINTR.
773 */
774 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
775 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
776 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700777 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700778 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779out:
780 spin_lock_irq(&ctx->ctx_lock);
781
782 if (-EIOCBRETRY == ret) {
783 /*
784 * OK, now that we are done with this iteration
785 * and know that there is more left to go,
786 * this is where we let go so that a subsequent
787 * "kick" can start the next iteration
788 */
789
790 /* will make __queue_kicked_iocb succeed from here on */
791 INIT_LIST_HEAD(&iocb->ki_run_list);
792 /* we must queue the next iteration ourselves, if it
793 * has already been kicked */
794 if (kiocbIsKicked(iocb)) {
795 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700796
797 /*
798 * __queue_kicked_iocb will always return 1 here, because
799 * iocb->ki_run_list is empty at this point so it should
800 * be safe to unconditionally queue the context into the
801 * work queue.
802 */
803 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 }
805 }
806 return ret;
807}
808
809/*
810 * __aio_run_iocbs:
811 * Process all pending retries queued on the ioctx
812 * run list.
813 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800814 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 */
816static int __aio_run_iocbs(struct kioctx *ctx)
817{
818 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700819 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820
Zach Brownd00689a2005-11-13 16:07:34 -0800821 assert_spin_locked(&ctx->ctx_lock);
822
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700823 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 while (!list_empty(&run_list)) {
825 iocb = list_entry(run_list.next, struct kiocb,
826 ki_run_list);
827 list_del(&iocb->ki_run_list);
828 /*
829 * Hold an extra reference while retrying i/o.
830 */
831 iocb->ki_users++; /* grab extra reference */
832 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800833 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 if (!list_empty(&ctx->run_list))
836 return 1;
837 return 0;
838}
839
840static void aio_queue_work(struct kioctx * ctx)
841{
842 unsigned long timeout;
843 /*
844 * if someone is waiting, get the work started right
845 * away, otherwise, use a longer delay
846 */
847 smp_mb();
848 if (waitqueue_active(&ctx->wait))
849 timeout = 1;
850 else
851 timeout = HZ/10;
852 queue_delayed_work(aio_wq, &ctx->wq, timeout);
853}
854
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855/*
Jeff Moyerd3486f82011-01-12 17:01:08 -0800856 * aio_run_all_iocbs:
857 * Process all pending retries queued on the ioctx
858 * run list, and keep running them until the list
859 * stays empty.
860 * Assumes it is operating within the aio issuer's mm context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 */
862static inline void aio_run_all_iocbs(struct kioctx *ctx)
863{
864 spin_lock_irq(&ctx->ctx_lock);
865 while (__aio_run_iocbs(ctx))
866 ;
867 spin_unlock_irq(&ctx->ctx_lock);
868}
869
870/*
871 * aio_kick_handler:
872 * Work queue handler triggered to process pending
873 * retries on an ioctx. Takes on the aio issuer's
874 * mm context before running the iocbs, so that
875 * copy_xxx_user operates on the issuer's address
876 * space.
877 * Run on aiod's context.
878 */
David Howells65f27f32006-11-22 14:55:48 +0000879static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880{
David Howells65f27f32006-11-22 14:55:48 +0000881 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800883 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 int requeue;
885
886 set_fs(USER_DS);
887 use_mm(ctx->mm);
888 spin_lock_irq(&ctx->ctx_lock);
889 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800890 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800892 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 set_fs(oldfs);
894 /*
Al Viro9fcf03d2012-03-13 22:06:28 -0400895 * we're in a worker thread already; no point using non-zero delay
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 */
897 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000898 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899}
900
901
902/*
903 * Called by kick_iocb to queue the kiocb for retry
904 * and if required activate the aio work queue to process
905 * it
906 */
Zach Brown998765e2005-09-30 11:58:54 -0700907static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908{
909 struct kioctx *ctx = iocb->ki_ctx;
910 unsigned long flags;
911 int run = 0;
912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700914 /* set this inside the lock so that we can't race with aio_run_iocb()
915 * testing it and putting the iocb on the run list under the lock */
916 if (!kiocbTryKick(iocb))
917 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700919 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921}
922
923/*
924 * kick_iocb:
925 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800926 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 * The retry is usually executed by aio workqueue
928 * threads (See aio_kick_handler).
929 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800930void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931{
932 /* sync iocbs are easy: they can only ever be executing from a
933 * single context. */
934 if (is_sync_kiocb(iocb)) {
935 kiocbSetKicked(iocb);
936 wake_up_process(iocb->ki_obj.tsk);
937 return;
938 }
939
Zach Brown998765e2005-09-30 11:58:54 -0700940 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941}
942EXPORT_SYMBOL(kick_iocb);
943
944/* aio_complete
945 * Called when the io request on the given iocb is complete.
946 * Returns true if this is the last user of the request. The
947 * only other user of the request can be the cancellation code.
948 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800949int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950{
951 struct kioctx *ctx = iocb->ki_ctx;
952 struct aio_ring_info *info;
953 struct aio_ring *ring;
954 struct io_event *event;
955 unsigned long flags;
956 unsigned long tail;
957 int ret;
958
Zach Brown20dcae32005-11-13 16:07:33 -0800959 /*
960 * Special case handling for sync iocbs:
961 * - events go directly into the iocb for fast handling
962 * - the sync task with the iocb in its stack holds the single iocb
963 * ref, no other paths have a way to get another ref
964 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 */
966 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800967 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800969 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800971 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 }
973
974 info = &ctx->ring_info;
975
976 /* add a completion event to the ring buffer.
977 * must be done holding ctx->ctx_lock to prevent
978 * other code from messing with the tail
979 * pointer since we might be called from irq
980 * context.
981 */
982 spin_lock_irqsave(&ctx->ctx_lock, flags);
983
984 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
985 list_del_init(&iocb->ki_run_list);
986
987 /*
988 * cancelled requests don't get events, userland was given one
989 * when the event got cancelled.
990 */
991 if (kiocbIsCancelled(iocb))
992 goto put_rq;
993
Cong Wange8e3c3d2011-11-25 23:14:27 +0800994 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995
996 tail = info->tail;
Cong Wange8e3c3d2011-11-25 23:14:27 +0800997 event = aio_ring_event(info, tail);
Ken Chen4bf69b22005-05-01 08:59:15 -0700998 if (++tail >= info->nr)
999 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000
1001 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
1002 event->data = iocb->ki_user_data;
1003 event->res = res;
1004 event->res2 = res2;
1005
1006 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
1007 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
1008 res, res2);
1009
1010 /* after flagging the request as done, we
1011 * must never even look at it again
1012 */
1013 smp_wmb(); /* make event visible before updating tail */
1014
1015 info->tail = tail;
1016 ring->tail = tail;
1017
Cong Wange8e3c3d2011-11-25 23:14:27 +08001018 put_aio_ring_event(event);
1019 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020
1021 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001022
1023 /*
1024 * Check if the user asked us to deliver the result through an
1025 * eventfd. The eventfd_signal() function is safe to be called
1026 * from IRQ context.
1027 */
Davide Libenzi87c3a862009-03-18 17:04:19 -07001028 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001029 eventfd_signal(iocb->ki_eventfd, 1);
1030
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031put_rq:
1032 /* everything turned out well, dispose of the aiocb. */
1033 ret = __aio_put_req(ctx, iocb);
1034
Quentin Barnes6cb2a212008-03-19 17:00:39 -07001035 /*
1036 * We have to order our ring_info tail store above and test
1037 * of the wait list below outside the wait lock. This is
1038 * like in wake_up_bit() where clearing a bit has to be
1039 * ordered with the unlocked test.
1040 */
1041 smp_mb();
1042
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 if (waitqueue_active(&ctx->wait))
1044 wake_up(&ctx->wait);
1045
Ken Chendee11c22007-02-03 01:13:45 -08001046 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 return ret;
1048}
H Hartley Sweeten385773e2009-09-22 16:43:53 -07001049EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050
1051/* aio_read_evt
1052 * Pull an event off of the ioctx's event ring. Returns the number of
1053 * events fetched (0 or 1 ;-)
1054 * FIXME: make this use cmpxchg.
1055 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1056 */
1057static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1058{
1059 struct aio_ring_info *info = &ioctx->ring_info;
1060 struct aio_ring *ring;
1061 unsigned long head;
1062 int ret = 0;
1063
Cong Wange8e3c3d2011-11-25 23:14:27 +08001064 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1066 (unsigned long)ring->head, (unsigned long)ring->tail,
1067 (unsigned long)ring->nr);
1068
1069 if (ring->head == ring->tail)
1070 goto out;
1071
1072 spin_lock(&info->ring_lock);
1073
1074 head = ring->head % info->nr;
1075 if (head != ring->tail) {
Cong Wange8e3c3d2011-11-25 23:14:27 +08001076 struct io_event *evp = aio_ring_event(info, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 *ent = *evp;
1078 head = (head + 1) % info->nr;
1079 smp_mb(); /* finish reading the event before updatng the head */
1080 ring->head = head;
1081 ret = 1;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001082 put_aio_ring_event(evp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 }
1084 spin_unlock(&info->ring_lock);
1085
1086out:
Cong Wange8e3c3d2011-11-25 23:14:27 +08001087 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1089 (unsigned long)ring->head, (unsigned long)ring->tail);
1090 return ret;
1091}
1092
1093struct aio_timeout {
1094 struct timer_list timer;
1095 int timed_out;
1096 struct task_struct *p;
1097};
1098
1099static void timeout_func(unsigned long data)
1100{
1101 struct aio_timeout *to = (struct aio_timeout *)data;
1102
1103 to->timed_out = 1;
1104 wake_up_process(to->p);
1105}
1106
1107static inline void init_timeout(struct aio_timeout *to)
1108{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001109 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 to->timed_out = 0;
1111 to->p = current;
1112}
1113
1114static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1115 const struct timespec *ts)
1116{
1117 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1118 if (time_after(to->timer.expires, jiffies))
1119 add_timer(&to->timer);
1120 else
1121 to->timed_out = 1;
1122}
1123
1124static inline void clear_timeout(struct aio_timeout *to)
1125{
1126 del_singleshot_timer_sync(&to->timer);
1127}
1128
1129static int read_events(struct kioctx *ctx,
1130 long min_nr, long nr,
1131 struct io_event __user *event,
1132 struct timespec __user *timeout)
1133{
1134 long start_jiffies = jiffies;
1135 struct task_struct *tsk = current;
1136 DECLARE_WAITQUEUE(wait, tsk);
1137 int ret;
1138 int i = 0;
1139 struct io_event ent;
1140 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 int retry = 0;
1142
1143 /* needed to zero any padding within an entry (there shouldn't be
1144 * any, but C is fun!
1145 */
1146 memset(&ent, 0, sizeof(ent));
1147retry:
1148 ret = 0;
1149 while (likely(i < nr)) {
1150 ret = aio_read_evt(ctx, &ent);
1151 if (unlikely(ret <= 0))
1152 break;
1153
1154 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1155 ent.data, ent.obj, ent.res, ent.res2);
1156
1157 /* Could we split the check in two? */
1158 ret = -EFAULT;
1159 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1160 dprintk("aio: lost an event due to EFAULT.\n");
1161 break;
1162 }
1163 ret = 0;
1164
1165 /* Good, event copied to userland, update counts. */
1166 event ++;
1167 i ++;
1168 }
1169
1170 if (min_nr <= i)
1171 return i;
1172 if (ret)
1173 return ret;
1174
1175 /* End fast path */
1176
1177 /* racey check, but it gets redone */
1178 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1179 retry = 1;
1180 aio_run_all_iocbs(ctx);
1181 goto retry;
1182 }
1183
1184 init_timeout(&to);
1185 if (timeout) {
1186 struct timespec ts;
1187 ret = -EFAULT;
1188 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1189 goto out;
1190
1191 set_timeout(start_jiffies, &to, &ts);
1192 }
1193
1194 while (likely(i < nr)) {
1195 add_wait_queue_exclusive(&ctx->wait, &wait);
1196 do {
1197 set_task_state(tsk, TASK_INTERRUPTIBLE);
1198 ret = aio_read_evt(ctx, &ent);
1199 if (ret)
1200 break;
1201 if (min_nr <= i)
1202 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001203 if (unlikely(ctx->dead)) {
1204 ret = -EINVAL;
1205 break;
1206 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 if (to.timed_out) /* Only check after read evt */
1208 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001209 /* Try to only show up in io wait if there are ops
1210 * in flight */
1211 if (ctx->reqs_active)
1212 io_schedule();
1213 else
1214 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 if (signal_pending(tsk)) {
1216 ret = -EINTR;
1217 break;
1218 }
1219 /*ret = aio_read_evt(ctx, &ent);*/
1220 } while (1) ;
1221
1222 set_task_state(tsk, TASK_RUNNING);
1223 remove_wait_queue(&ctx->wait, &wait);
1224
1225 if (unlikely(ret <= 0))
1226 break;
1227
1228 ret = -EFAULT;
1229 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1230 dprintk("aio: lost an event due to EFAULT.\n");
1231 break;
1232 }
1233
1234 /* Good, event copied to userland, update counts. */
1235 event ++;
1236 i ++;
1237 }
1238
1239 if (timeout)
1240 clear_timeout(&to);
1241out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001242 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 return i ? i : ret;
1244}
1245
1246/* Take an ioctx and remove it from the list of ioctx's. Protects
1247 * against races with itself via ->dead.
1248 */
1249static void io_destroy(struct kioctx *ioctx)
1250{
1251 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 int was_dead;
1253
1254 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001255 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 was_dead = ioctx->dead;
1257 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001258 hlist_del_rcu(&ioctx->list);
1259 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260
1261 dprintk("aio_release(%p)\n", ioctx);
1262 if (likely(!was_dead))
1263 put_ioctx(ioctx); /* twice for the list */
1264
Al Viro06af1212012-03-20 16:26:24 -04001265 kill_ctx(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001266
1267 /*
1268 * Wake up any waiters. The setting of ctx->dead must be seen
1269 * by other CPUs at this point. Right now, we rely on the
1270 * locking done by the above calls to ensure this consistency.
1271 */
Roland Dreiere91f90b2011-03-22 16:35:10 -07001272 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273}
1274
1275/* sys_io_setup:
1276 * Create an aio_context capable of receiving at least nr_events.
1277 * ctxp must not point to an aio_context that already exists, and
1278 * must be initialized to 0 prior to the call. On successful
1279 * creation of the aio_context, *ctxp is filled in with the resulting
1280 * handle. May fail with -EINVAL if *ctxp is not initialized,
1281 * if the specified nr_events exceeds internal limits. May fail
1282 * with -EAGAIN if the specified nr_events exceeds the user's limit
1283 * of available events. May fail with -ENOMEM if insufficient kernel
1284 * resources are available. May fail with -EFAULT if an invalid
1285 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1286 * implemented.
1287 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001288SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289{
1290 struct kioctx *ioctx = NULL;
1291 unsigned long ctx;
1292 long ret;
1293
1294 ret = get_user(ctx, ctxp);
1295 if (unlikely(ret))
1296 goto out;
1297
1298 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001299 if (unlikely(ctx || nr_events == 0)) {
1300 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1301 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 goto out;
1303 }
1304
1305 ioctx = ioctx_alloc(nr_events);
1306 ret = PTR_ERR(ioctx);
1307 if (!IS_ERR(ioctx)) {
1308 ret = put_user(ioctx->user_id, ctxp);
Al Viroa2e18592012-03-20 16:27:57 -04001309 if (ret)
1310 io_destroy(ioctx);
1311 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 }
1313
1314out:
1315 return ret;
1316}
1317
1318/* sys_io_destroy:
1319 * Destroy the aio_context specified. May cancel any outstanding
1320 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001321 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 * is invalid.
1323 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001324SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325{
1326 struct kioctx *ioctx = lookup_ioctx(ctx);
1327 if (likely(NULL != ioctx)) {
1328 io_destroy(ioctx);
Al Viroa2e18592012-03-20 16:27:57 -04001329 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 return 0;
1331 }
1332 pr_debug("EINVAL: io_destroy: invalid context id\n");
1333 return -EINVAL;
1334}
1335
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001336static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1337{
1338 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1339
1340 BUG_ON(ret <= 0);
1341
1342 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1343 ssize_t this = min((ssize_t)iov->iov_len, ret);
1344 iov->iov_base += this;
1345 iov->iov_len -= this;
1346 iocb->ki_left -= this;
1347 ret -= this;
1348 if (iov->iov_len == 0) {
1349 iocb->ki_cur_seg++;
1350 iov++;
1351 }
1352 }
1353
1354 /* the caller should not have done more io than what fit in
1355 * the remaining iovecs */
1356 BUG_ON(ret > 0 && iocb->ki_left == 0);
1357}
1358
1359static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360{
1361 struct file *file = iocb->ki_filp;
1362 struct address_space *mapping = file->f_mapping;
1363 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001364 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1365 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001367 unsigned short opcode;
1368
1369 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1370 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1371 rw_op = file->f_op->aio_read;
1372 opcode = IOCB_CMD_PREADV;
1373 } else {
1374 rw_op = file->f_op->aio_write;
1375 opcode = IOCB_CMD_PWRITEV;
1376 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377
Rusty Russellc2ec6682008-02-08 04:20:15 -08001378 /* This matches the pread()/pwrite() logic */
1379 if (iocb->ki_pos < 0)
1380 return -EINVAL;
1381
Zach Brown897f15f2005-09-30 11:58:55 -07001382 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001383 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1384 iocb->ki_nr_segs - iocb->ki_cur_seg,
1385 iocb->ki_pos);
1386 if (ret > 0)
1387 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001388
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001389 /* retry all partial writes. retry partial reads as long as its a
1390 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001391 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001392 (opcode == IOCB_CMD_PWRITEV ||
1393 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394
1395 /* This means we must have transferred all that we could */
1396 /* No need to retry anymore */
1397 if ((ret == 0) || (iocb->ki_left == 0))
1398 ret = iocb->ki_nbytes - iocb->ki_left;
1399
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001400 /* If we managed to write some out we return that, rather than
1401 * the eventual error. */
1402 if (opcode == IOCB_CMD_PWRITEV
1403 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1404 && iocb->ki_nbytes - iocb->ki_left)
1405 ret = iocb->ki_nbytes - iocb->ki_left;
1406
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407 return ret;
1408}
1409
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410static ssize_t aio_fdsync(struct kiocb *iocb)
1411{
1412 struct file *file = iocb->ki_filp;
1413 ssize_t ret = -EINVAL;
1414
1415 if (file->f_op->aio_fsync)
1416 ret = file->f_op->aio_fsync(iocb, 1);
1417 return ret;
1418}
1419
1420static ssize_t aio_fsync(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, 0);
1427 return ret;
1428}
1429
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001430static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001431{
1432 ssize_t ret;
1433
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001434#ifdef CONFIG_COMPAT
1435 if (compat)
1436 ret = compat_rw_copy_check_uvector(type,
1437 (struct compat_iovec __user *)kiocb->ki_buf,
1438 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001439 &kiocb->ki_iovec, 1);
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001440 else
1441#endif
1442 ret = rw_copy_check_uvector(type,
1443 (struct iovec __user *)kiocb->ki_buf,
1444 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001445 &kiocb->ki_iovec, 1);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001446 if (ret < 0)
1447 goto out;
1448
1449 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1450 kiocb->ki_cur_seg = 0;
1451 /* ki_nbytes/left now reflect bytes instead of segs */
1452 kiocb->ki_nbytes = ret;
1453 kiocb->ki_left = ret;
1454
1455 ret = 0;
1456out:
1457 return ret;
1458}
1459
1460static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1461{
1462 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1463 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1464 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1465 kiocb->ki_nr_segs = 1;
1466 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001467 return 0;
1468}
1469
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470/*
1471 * aio_setup_iocb:
1472 * Performs the initial checks and aio retry method
1473 * setup for the kiocb at the time of io submission.
1474 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001475static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476{
1477 struct file *file = kiocb->ki_filp;
1478 ssize_t ret = 0;
1479
1480 switch (kiocb->ki_opcode) {
1481 case IOCB_CMD_PREAD:
1482 ret = -EBADF;
1483 if (unlikely(!(file->f_mode & FMODE_READ)))
1484 break;
1485 ret = -EFAULT;
1486 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1487 kiocb->ki_left)))
1488 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001489 ret = security_file_permission(file, MAY_READ);
1490 if (unlikely(ret))
1491 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001492 ret = aio_setup_single_vector(kiocb);
1493 if (ret)
1494 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 ret = -EINVAL;
1496 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001497 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498 break;
1499 case IOCB_CMD_PWRITE:
1500 ret = -EBADF;
1501 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1502 break;
1503 ret = -EFAULT;
1504 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1505 kiocb->ki_left)))
1506 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001507 ret = security_file_permission(file, MAY_WRITE);
1508 if (unlikely(ret))
1509 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001510 ret = aio_setup_single_vector(kiocb);
1511 if (ret)
1512 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513 ret = -EINVAL;
1514 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001515 kiocb->ki_retry = aio_rw_vect_retry;
1516 break;
1517 case IOCB_CMD_PREADV:
1518 ret = -EBADF;
1519 if (unlikely(!(file->f_mode & FMODE_READ)))
1520 break;
1521 ret = security_file_permission(file, MAY_READ);
1522 if (unlikely(ret))
1523 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001524 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001525 if (ret)
1526 break;
1527 ret = -EINVAL;
1528 if (file->f_op->aio_read)
1529 kiocb->ki_retry = aio_rw_vect_retry;
1530 break;
1531 case IOCB_CMD_PWRITEV:
1532 ret = -EBADF;
1533 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1534 break;
1535 ret = security_file_permission(file, MAY_WRITE);
1536 if (unlikely(ret))
1537 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001538 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001539 if (ret)
1540 break;
1541 ret = -EINVAL;
1542 if (file->f_op->aio_write)
1543 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544 break;
1545 case IOCB_CMD_FDSYNC:
1546 ret = -EINVAL;
1547 if (file->f_op->aio_fsync)
1548 kiocb->ki_retry = aio_fdsync;
1549 break;
1550 case IOCB_CMD_FSYNC:
1551 ret = -EINVAL;
1552 if (file->f_op->aio_fsync)
1553 kiocb->ki_retry = aio_fsync;
1554 break;
1555 default:
1556 dprintk("EINVAL: io_submit: no operation provided\n");
1557 ret = -EINVAL;
1558 }
1559
1560 if (!kiocb->ki_retry)
1561 return ret;
1562
1563 return 0;
1564}
1565
Adrian Bunkd5470b52008-04-29 00:58:57 -07001566static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer080d6762011-11-02 13:40:10 -07001567 struct iocb *iocb, struct kiocb_batch *batch,
1568 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569{
1570 struct kiocb *req;
1571 struct file *file;
1572 ssize_t ret;
1573
1574 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001575 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 pr_debug("EINVAL: io_submit: reserve field set\n");
1577 return -EINVAL;
1578 }
1579
1580 /* prevent overflows */
1581 if (unlikely(
1582 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1583 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1584 ((ssize_t)iocb->aio_nbytes < 0)
1585 )) {
1586 pr_debug("EINVAL: io_submit: overflow check\n");
1587 return -EINVAL;
1588 }
1589
1590 file = fget(iocb->aio_fildes);
1591 if (unlikely(!file))
1592 return -EBADF;
1593
Jeff Moyer080d6762011-11-02 13:40:10 -07001594 req = aio_get_req(ctx, batch); /* returns with 2 references to req */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595 if (unlikely(!req)) {
1596 fput(file);
1597 return -EAGAIN;
1598 }
Yan Zheng87e28312007-10-08 12:16:20 -07001599 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001600 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1601 /*
1602 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1603 * instance of the file* now. The file descriptor must be
1604 * an eventfd() fd, and will be signaled for each completed
1605 * event using the eventfd_signal() function.
1606 */
Davide Libenzi13389012009-06-30 11:41:11 -07001607 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001608 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001609 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001610 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001611 goto out_put_req;
1612 }
1613 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614
Ken Chen212079c2005-05-01 08:59:15 -07001615 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616 if (unlikely(ret)) {
1617 dprintk("EFAULT: aio_key\n");
1618 goto out_put_req;
1619 }
1620
1621 req->ki_obj.user = user_iocb;
1622 req->ki_user_data = iocb->aio_data;
1623 req->ki_pos = iocb->aio_offset;
1624
1625 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1626 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1627 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001629 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630
1631 if (ret)
1632 goto out_put_req;
1633
1634 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001635 /*
1636 * We could have raced with io_destroy() and are currently holding a
1637 * reference to ctx which should be destroyed. We cannot submit IO
1638 * since ctx gets freed as soon as io_submit() puts its reference. The
1639 * check here is reliable: io_destroy() sets ctx->dead before waiting
1640 * for outstanding IO and the barrier between these two is realized by
1641 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1642 * increment ctx->reqs_active before checking for ctx->dead and the
1643 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1644 * don't see ctx->dead set here, io_destroy() waits for our IO to
1645 * finish.
1646 */
1647 if (ctx->dead) {
1648 spin_unlock_irq(&ctx->ctx_lock);
1649 ret = -EINVAL;
1650 goto out_put_req;
1651 }
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001652 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001653 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001654 /* drain the run list */
1655 while (__aio_run_iocbs(ctx))
1656 ;
1657 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001659
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660 aio_put_req(req); /* drop extra ref to req */
1661 return 0;
1662
1663out_put_req:
1664 aio_put_req(req); /* drop extra ref to req */
1665 aio_put_req(req); /* drop i/o ref to req */
1666 return ret;
1667}
1668
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001669long do_io_submit(aio_context_t ctx_id, long nr,
1670 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671{
1672 struct kioctx *ctx;
1673 long ret = 0;
Jeff Moyer080d6762011-11-02 13:40:10 -07001674 int i = 0;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001675 struct blk_plug plug;
Jeff Moyer080d6762011-11-02 13:40:10 -07001676 struct kiocb_batch batch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677
1678 if (unlikely(nr < 0))
1679 return -EINVAL;
1680
Jeff Moyer75e1c702010-09-10 14:16:00 -07001681 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1682 nr = LONG_MAX/sizeof(*iocbpp);
1683
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1685 return -EFAULT;
1686
1687 ctx = lookup_ioctx(ctx_id);
1688 if (unlikely(!ctx)) {
1689 pr_debug("EINVAL: io_submit: invalid context id\n");
1690 return -EINVAL;
1691 }
1692
Jeff Moyer080d6762011-11-02 13:40:10 -07001693 kiocb_batch_init(&batch, nr);
1694
Shaohua Li9f5b9422010-07-01 07:55:01 +02001695 blk_start_plug(&plug);
1696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 /*
1698 * AKPM: should this return a partial result if some of the IOs were
1699 * successfully submitted?
1700 */
1701 for (i=0; i<nr; i++) {
1702 struct iocb __user *user_iocb;
1703 struct iocb tmp;
1704
1705 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1706 ret = -EFAULT;
1707 break;
1708 }
1709
1710 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1711 ret = -EFAULT;
1712 break;
1713 }
1714
Jeff Moyer080d6762011-11-02 13:40:10 -07001715 ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716 if (ret)
1717 break;
1718 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001719 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720
Gleb Natapov69e47472012-01-08 17:07:28 +02001721 kiocb_batch_free(ctx, &batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 put_ioctx(ctx);
1723 return i ? i : ret;
1724}
1725
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001726/* sys_io_submit:
1727 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1728 * the number of iocbs queued. May return -EINVAL if the aio_context
1729 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1730 * *iocbpp[0] is not properly initialized, if the operation specified
1731 * is invalid for the file descriptor in the iocb. May fail with
1732 * -EFAULT if any of the data structures point to invalid data. May
1733 * fail with -EBADF if the file descriptor specified in the first
1734 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1735 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1736 * fail with -ENOSYS if not implemented.
1737 */
1738SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1739 struct iocb __user * __user *, iocbpp)
1740{
1741 return do_io_submit(ctx_id, nr, iocbpp, 0);
1742}
1743
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744/* lookup_kiocb
1745 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001747static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1748 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749{
1750 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001751
1752 assert_spin_locked(&ctx->ctx_lock);
1753
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 /* TODO: use a hash or array, this sucks. */
1755 list_for_each(pos, &ctx->active_reqs) {
1756 struct kiocb *kiocb = list_kiocb(pos);
1757 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1758 return kiocb;
1759 }
1760 return NULL;
1761}
1762
1763/* sys_io_cancel:
1764 * Attempts to cancel an iocb previously passed to io_submit. If
1765 * the operation is successfully cancelled, the resulting event is
1766 * copied into the memory pointed to by result without being placed
1767 * into the completion queue and 0 is returned. May fail with
1768 * -EFAULT if any of the data structures pointed to are invalid.
1769 * May fail with -EINVAL if aio_context specified by ctx_id is
1770 * invalid. May fail with -EAGAIN if the iocb specified was not
1771 * cancelled. Will fail with -ENOSYS if not implemented.
1772 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001773SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1774 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775{
1776 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1777 struct kioctx *ctx;
1778 struct kiocb *kiocb;
1779 u32 key;
1780 int ret;
1781
1782 ret = get_user(key, &iocb->aio_key);
1783 if (unlikely(ret))
1784 return -EFAULT;
1785
1786 ctx = lookup_ioctx(ctx_id);
1787 if (unlikely(!ctx))
1788 return -EINVAL;
1789
1790 spin_lock_irq(&ctx->ctx_lock);
1791 ret = -EAGAIN;
1792 kiocb = lookup_kiocb(ctx, iocb, key);
1793 if (kiocb && kiocb->ki_cancel) {
1794 cancel = kiocb->ki_cancel;
1795 kiocb->ki_users ++;
1796 kiocbSetCancelled(kiocb);
1797 } else
1798 cancel = NULL;
1799 spin_unlock_irq(&ctx->ctx_lock);
1800
1801 if (NULL != cancel) {
1802 struct io_event tmp;
1803 pr_debug("calling cancel\n");
1804 memset(&tmp, 0, sizeof(tmp));
1805 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1806 tmp.data = kiocb->ki_user_data;
1807 ret = cancel(kiocb, &tmp);
1808 if (!ret) {
1809 /* Cancellation succeeded -- copy the result
1810 * into the user's buffer.
1811 */
1812 if (copy_to_user(result, &tmp, sizeof(tmp)))
1813 ret = -EFAULT;
1814 }
1815 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001816 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817
1818 put_ioctx(ctx);
1819
1820 return ret;
1821}
1822
1823/* io_getevents:
1824 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001825 * the completion queue for the aio_context specified by ctx_id. If
1826 * it succeeds, the number of read events is returned. May fail with
1827 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1828 * out of range, if timeout is out of range. May fail with -EFAULT
1829 * if any of the memory specified is invalid. May return 0 or
1830 * < min_nr if the timeout specified by timeout has elapsed
1831 * before sufficient events are available, where timeout == NULL
1832 * specifies an infinite timeout. Note that the timeout pointed to by
1833 * timeout is relative and will be updated if not NULL and the
1834 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001836SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1837 long, min_nr,
1838 long, nr,
1839 struct io_event __user *, events,
1840 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841{
1842 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1843 long ret = -EINVAL;
1844
1845 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001846 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847 ret = read_events(ioctx, min_nr, nr, events, timeout);
1848 put_ioctx(ioctx);
1849 }
1850
Roland McGrath598af052008-04-10 15:38:45 -07001851 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852 return ret;
1853}