blob: 3f941f2a305949f31ba9dce2a4e87f6849e8ab71 [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
David Howells65f27f32006-11-22 14:55:48 +000059static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070060static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62/* aio_setup
63 * Creates the slab caches used by the aio routines, panic on
64 * failure as this is done early during the boot sequence.
65 */
66static int __init aio_setup(void)
67{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070068 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
69 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Tejun Heod37adaa2011-01-26 17:42:27 +010071 aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */
Jens Axboecf159002011-03-02 20:12:18 -050072 BUG_ON(!aio_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
75
76 return 0;
77}
H Hartley Sweeten385773e2009-09-22 16:43:53 -070078__initcall(aio_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
80static void aio_free_ring(struct kioctx *ctx)
81{
82 struct aio_ring_info *info = &ctx->ring_info;
83 long i;
84
85 for (i=0; i<info->nr_pages; i++)
86 put_page(info->ring_pages[i]);
87
Al Viro936af152012-04-20 21:49:41 -040088 if (info->mmap_size) {
89 BUG_ON(ctx->mm != current->mm);
Al Virobfce2812012-04-20 21:57:04 -040090 vm_munmap(info->mmap_base, info->mmap_size);
Al Viro936af152012-04-20 21:49:41 -040091 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
93 if (info->ring_pages && info->ring_pages != info->internal_pages)
94 kfree(info->ring_pages);
95 info->ring_pages = NULL;
96 info->nr = 0;
97}
98
99static int aio_setup_ring(struct kioctx *ctx)
100{
101 struct aio_ring *ring;
102 struct aio_ring_info *info = &ctx->ring_info;
103 unsigned nr_events = ctx->max_reqs;
Michel Lespinasse41badc12013-02-22 16:32:47 -0800104 unsigned long size, populate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 int nr_pages;
106
107 /* Compensate for the ring buffer's head/tail overlap entry */
108 nr_events += 2; /* 1 is required, 2 for good luck */
109
110 size = sizeof(struct aio_ring);
111 size += sizeof(struct io_event) * nr_events;
112 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
113
114 if (nr_pages < 0)
115 return -EINVAL;
116
117 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
118
119 info->nr = 0;
120 info->ring_pages = info->internal_pages;
121 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800122 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 if (!info->ring_pages)
124 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 }
126
127 info->mmap_size = nr_pages * PAGE_SIZE;
128 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
129 down_write(&ctx->mm->mmap_sem);
Al Viroe3fc6292012-05-30 20:08:42 -0400130 info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size,
131 PROT_READ|PROT_WRITE,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800132 MAP_ANONYMOUS|MAP_PRIVATE, 0,
133 &populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 if (IS_ERR((void *)info->mmap_base)) {
135 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 info->mmap_size = 0;
137 aio_free_ring(ctx);
138 return -EAGAIN;
139 }
140
141 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
142 info->nr_pages = get_user_pages(current, ctx->mm,
143 info->mmap_base, nr_pages,
144 1, 0, info->ring_pages, NULL);
145 up_write(&ctx->mm->mmap_sem);
146
147 if (unlikely(info->nr_pages != nr_pages)) {
148 aio_free_ring(ctx);
149 return -EAGAIN;
150 }
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800151 if (populate)
Michel Lespinasse41badc12013-02-22 16:32:47 -0800152 mm_populate(info->mmap_base, populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 ctx->user_id = info->mmap_base;
155
156 info->nr = nr_events; /* trusted copy */
157
Cong Wange8e3c3d2011-11-25 23:14:27 +0800158 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 ring->nr = nr_events; /* user copy */
160 ring->id = ctx->user_id;
161 ring->head = ring->tail = 0;
162 ring->magic = AIO_RING_MAGIC;
163 ring->compat_features = AIO_RING_COMPAT_FEATURES;
164 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
165 ring->header_length = sizeof(struct aio_ring);
Cong Wange8e3c3d2011-11-25 23:14:27 +0800166 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
168 return 0;
169}
170
171
172/* aio_ring_event: returns a pointer to the event at the given index from
Cong Wange8e3c3d2011-11-25 23:14:27 +0800173 * kmap_atomic(). Release the pointer with put_aio_ring_event();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 */
175#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
176#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
177#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
178
Cong Wange8e3c3d2011-11-25 23:14:27 +0800179#define aio_ring_event(info, nr) ({ \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
181 struct io_event *__event; \
182 __event = kmap_atomic( \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800183 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 __event += pos % AIO_EVENTS_PER_PAGE; \
185 __event; \
186})
187
Cong Wange8e3c3d2011-11-25 23:14:27 +0800188#define put_aio_ring_event(event) do { \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 struct io_event *__event = (event); \
190 (void)__event; \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800191 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192} while(0)
193
Jens Axboeabf137d2008-12-09 08:11:22 +0100194static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700195{
Jens Axboeabf137d2008-12-09 08:11:22 +0100196 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700197 kmem_cache_free(kioctx_cachep, ctx);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700198}
199
Jens Axboeabf137d2008-12-09 08:11:22 +0100200/* __put_ioctx
201 * Called when the last user of an aio context has gone away,
202 * and the struct needs to be freed.
203 */
204static void __put_ioctx(struct kioctx *ctx)
205{
Al Viro2dd542b2012-03-10 23:10:35 -0500206 unsigned nr_events = ctx->max_reqs;
Jens Axboeabf137d2008-12-09 08:11:22 +0100207 BUG_ON(ctx->reqs_active);
208
Al Virobf507222012-03-11 00:58:40 -0500209 cancel_delayed_work_sync(&ctx->wq);
Jens Axboeabf137d2008-12-09 08:11:22 +0100210 aio_free_ring(ctx);
211 mmdrop(ctx->mm);
212 ctx->mm = NULL;
Al Viro2dd542b2012-03-10 23:10:35 -0500213 if (nr_events) {
214 spin_lock(&aio_nr_lock);
215 BUG_ON(aio_nr - nr_events > aio_nr);
216 aio_nr -= nr_events;
217 spin_unlock(&aio_nr_lock);
218 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100219 pr_debug("__put_ioctx: freeing %p\n", ctx);
220 call_rcu(&ctx->rcu_head, ctx_rcu_free);
221}
222
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800223static inline int try_get_ioctx(struct kioctx *kioctx)
224{
225 return atomic_inc_not_zero(&kioctx->users);
226}
227
228static inline void put_ioctx(struct kioctx *kioctx)
229{
230 BUG_ON(atomic_read(&kioctx->users) <= 0);
231 if (unlikely(atomic_dec_and_test(&kioctx->users)))
232 __put_ioctx(kioctx);
233}
Adrian Bunkd5470b52008-04-29 00:58:57 -0700234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235/* ioctx_alloc
236 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
237 */
238static struct kioctx *ioctx_alloc(unsigned nr_events)
239{
240 struct mm_struct *mm;
241 struct kioctx *ctx;
Al Viroe23754f2012-03-06 14:33:22 -0500242 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
244 /* Prevent overflows */
245 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
246 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
247 pr_debug("ENOMEM: nr_events too high\n");
248 return ERR_PTR(-EINVAL);
249 }
250
Al Viro2dd542b2012-03-10 23:10:35 -0500251 if (!nr_events || (unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 return ERR_PTR(-EAGAIN);
253
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800254 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 if (!ctx)
256 return ERR_PTR(-ENOMEM);
257
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 ctx->max_reqs = nr_events;
259 mm = ctx->mm = current->mm;
260 atomic_inc(&mm->mm_count);
261
Al Viro86b62a22012-03-07 05:16:35 +0000262 atomic_set(&ctx->users, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 spin_lock_init(&ctx->ctx_lock);
264 spin_lock_init(&ctx->ring_info.ring_lock);
265 init_waitqueue_head(&ctx->wait);
266
267 INIT_LIST_HEAD(&ctx->active_reqs);
268 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000269 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
271 if (aio_setup_ring(ctx) < 0)
272 goto out_freectx;
273
274 /* limit the number of system wide aios */
Al Viro9fa1cb32012-03-10 23:14:05 -0500275 spin_lock(&aio_nr_lock);
Al Viro2dd542b2012-03-10 23:10:35 -0500276 if (aio_nr + nr_events > aio_max_nr ||
277 aio_nr + nr_events < aio_nr) {
Al Viro9fa1cb32012-03-10 23:14:05 -0500278 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 goto out_cleanup;
Al Viro2dd542b2012-03-10 23:10:35 -0500280 }
281 aio_nr += ctx->max_reqs;
Al Viro9fa1cb32012-03-10 23:14:05 -0500282 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
Jeff Moyer39fa0032008-04-29 01:03:48 -0700284 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100285 spin_lock(&mm->ioctx_lock);
286 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
287 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
289 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
290 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
291 return ctx;
292
293out_cleanup:
Al Viroe23754f2012-03-06 14:33:22 -0500294 err = -EAGAIN;
295 aio_free_ring(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296out_freectx:
297 mmdrop(mm);
298 kmem_cache_free(kioctx_cachep, ctx);
Al Viroe23754f2012-03-06 14:33:22 -0500299 dprintk("aio: error allocating ioctx %d\n", err);
300 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301}
302
Al Viro06af1212012-03-20 16:26:24 -0400303/* kill_ctx
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 * Cancels all outstanding aio requests on an aio context. Used
305 * when the processes owning a context have all exited to encourage
306 * the rapid destruction of the kioctx.
307 */
Al Viro06af1212012-03-20 16:26:24 -0400308static void kill_ctx(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
310 int (*cancel)(struct kiocb *, struct io_event *);
Al Viro06af1212012-03-20 16:26:24 -0400311 struct task_struct *tsk = current;
312 DECLARE_WAITQUEUE(wait, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 struct io_event res;
Al Viro06af1212012-03-20 16:26:24 -0400314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 spin_lock_irq(&ctx->ctx_lock);
316 ctx->dead = 1;
317 while (!list_empty(&ctx->active_reqs)) {
318 struct list_head *pos = ctx->active_reqs.next;
319 struct kiocb *iocb = list_kiocb(pos);
320 list_del_init(&iocb->ki_list);
321 cancel = iocb->ki_cancel;
322 kiocbSetCancelled(iocb);
323 if (cancel) {
324 iocb->ki_users++;
325 spin_unlock_irq(&ctx->ctx_lock);
326 cancel(iocb, &res);
327 spin_lock_irq(&ctx->ctx_lock);
328 }
329 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800332 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
334 add_wait_queue(&ctx->wait, &wait);
335 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
336 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800337 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700338 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800340 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 }
342 __set_task_state(tsk, TASK_RUNNING);
343 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800344
345out:
346 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347}
348
349/* wait_on_sync_kiocb:
350 * Waits on the given sync kiocb to complete.
351 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800352ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353{
354 while (iocb->ki_users) {
355 set_current_state(TASK_UNINTERRUPTIBLE);
356 if (!iocb->ki_users)
357 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700358 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 }
360 __set_current_state(TASK_RUNNING);
361 return iocb->ki_user_data;
362}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700363EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
365/* exit_aio: called when the last user of mm goes away. At this point,
366 * there is no way for any new requests to be submited or any of the
367 * io_* syscalls to be called on the context. However, there may be
368 * outstanding requests which hold references to the context; as they
369 * go away, they will call put_ioctx and release any pinned memory
370 * associated with the request (held via struct page * references).
371 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800372void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373{
Jens Axboeabf137d2008-12-09 08:11:22 +0100374 struct kioctx *ctx;
375
376 while (!hlist_empty(&mm->ioctx_list)) {
377 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
378 hlist_del_rcu(&ctx->list);
379
Al Viro06af1212012-03-20 16:26:24 -0400380 kill_ctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382 if (1 != atomic_read(&ctx->users))
383 printk(KERN_DEBUG
384 "exit_aio:ioctx still alive: %d %d %d\n",
385 atomic_read(&ctx->users), ctx->dead,
386 ctx->reqs_active);
Al Viro936af152012-04-20 21:49:41 -0400387 /*
388 * We don't need to bother with munmap() here -
389 * exit_mmap(mm) is coming and it'll unmap everything.
390 * Since aio_free_ring() uses non-zero ->mmap_size
391 * as indicator that it needs to unmap the area,
392 * just set it to 0; aio_free_ring() is the only
393 * place that uses ->mmap_size, so it's safe.
394 * That way we get all munmap done to current->mm -
395 * all other callers have ctx->mm == current->mm.
396 */
397 ctx->ring_info.mmap_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 }
400}
401
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402/* aio_get_req
403 * Allocate a slot for an aio request. Increments the users count
404 * of the kioctx so that the kioctx stays around until all requests are
405 * complete. Returns NULL if no requests are free.
406 *
407 * Returns with kiocb->users set to 2. The io submit code path holds
408 * an extra reference while submitting the i/o.
409 * This prevents races between the aio code path referencing the
410 * req (after submitting it) and aio_complete() freeing the req.
411 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800412static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413{
414 struct kiocb *req = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415
416 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
417 if (unlikely(!req))
418 return NULL;
419
Zach Brown4faa5282005-10-17 16:43:33 -0700420 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 req->ki_users = 2;
422 req->ki_key = 0;
423 req->ki_ctx = ctx;
424 req->ki_cancel = NULL;
425 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 req->ki_dtor = NULL;
427 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700428 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700430 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 return req;
433}
434
Jeff Moyer080d6762011-11-02 13:40:10 -0700435/*
436 * struct kiocb's are allocated in batches to reduce the number of
437 * times the ctx lock is acquired and released.
438 */
439#define KIOCB_BATCH_SIZE 32L
440struct kiocb_batch {
441 struct list_head head;
442 long count; /* number of requests left to allocate */
443};
444
445static void kiocb_batch_init(struct kiocb_batch *batch, long total)
446{
447 INIT_LIST_HEAD(&batch->head);
448 batch->count = total;
449}
450
Gleb Natapov69e47472012-01-08 17:07:28 +0200451static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
Jeff Moyer080d6762011-11-02 13:40:10 -0700452{
453 struct kiocb *req, *n;
454
Gleb Natapov69e47472012-01-08 17:07:28 +0200455 if (list_empty(&batch->head))
456 return;
457
458 spin_lock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700459 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
460 list_del(&req->ki_batch);
Gleb Natapov69e47472012-01-08 17:07:28 +0200461 list_del(&req->ki_list);
Jeff Moyer080d6762011-11-02 13:40:10 -0700462 kmem_cache_free(kiocb_cachep, req);
Gleb Natapov69e47472012-01-08 17:07:28 +0200463 ctx->reqs_active--;
Jeff Moyer080d6762011-11-02 13:40:10 -0700464 }
Jeff Moyer880641b2012-03-05 14:59:12 -0800465 if (unlikely(!ctx->reqs_active && ctx->dead))
466 wake_up_all(&ctx->wait);
Gleb Natapov69e47472012-01-08 17:07:28 +0200467 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700468}
469
470/*
471 * Allocate a batch of kiocbs. This avoids taking and dropping the
472 * context lock a lot during setup.
473 */
474static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
475{
476 unsigned short allocated, to_alloc;
477 long avail;
Jeff Moyer080d6762011-11-02 13:40:10 -0700478 struct kiocb *req, *n;
479 struct aio_ring *ring;
480
481 to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
482 for (allocated = 0; allocated < to_alloc; allocated++) {
483 req = __aio_get_req(ctx);
484 if (!req)
485 /* allocation failed, go with what we've got */
486 break;
487 list_add(&req->ki_batch, &batch->head);
488 }
489
490 if (allocated == 0)
491 goto out;
492
Jeff Moyer080d6762011-11-02 13:40:10 -0700493 spin_lock_irq(&ctx->ctx_lock);
494 ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
495
496 avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active;
497 BUG_ON(avail < 0);
Jeff Moyer080d6762011-11-02 13:40:10 -0700498 if (avail < allocated) {
499 /* Trim back the number of requests. */
500 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
501 list_del(&req->ki_batch);
502 kmem_cache_free(kiocb_cachep, req);
503 if (--allocated <= avail)
504 break;
505 }
506 }
507
508 batch->count -= allocated;
509 list_for_each_entry(req, &batch->head, ki_batch) {
510 list_add(&req->ki_list, &ctx->active_reqs);
511 ctx->reqs_active++;
512 }
513
514 kunmap_atomic(ring);
515 spin_unlock_irq(&ctx->ctx_lock);
516
517out:
518 return allocated;
519}
520
521static inline struct kiocb *aio_get_req(struct kioctx *ctx,
522 struct kiocb_batch *batch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523{
524 struct kiocb *req;
Jeff Moyer080d6762011-11-02 13:40:10 -0700525
526 if (list_empty(&batch->head))
527 if (kiocb_batch_refill(ctx, batch) == 0)
528 return NULL;
529 req = list_first_entry(&batch->head, struct kiocb, ki_batch);
530 list_del(&req->ki_batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 return req;
532}
533
534static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
535{
Zach Brownd00689a2005-11-13 16:07:34 -0800536 assert_spin_locked(&ctx->ctx_lock);
537
Davide Libenzi13389012009-06-30 11:41:11 -0700538 if (req->ki_eventfd != NULL)
539 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 if (req->ki_dtor)
541 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700542 if (req->ki_iovec != &req->ki_inline_vec)
543 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 kmem_cache_free(kiocb_cachep, req);
545 ctx->reqs_active--;
546
547 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700548 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549}
550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551/* __aio_put_req
552 * Returns true if this put was the last user of the request.
553 */
554static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
555{
Al Viro516e0cc2008-07-26 00:39:17 -0400556 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
557 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558
Zach Brownd00689a2005-11-13 16:07:34 -0800559 assert_spin_locked(&ctx->ctx_lock);
560
Davide Libenzi87c3a862009-03-18 17:04:19 -0700561 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100562 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 if (likely(req->ki_users))
564 return 0;
565 list_del(&req->ki_list); /* remove from active_reqs */
566 req->ki_cancel = NULL;
567 req->ki_retry = NULL;
568
Al Viro3ffa3c02012-06-24 10:00:10 +0400569 fput(req->ki_filp);
570 req->ki_filp = NULL;
571 really_put_req(ctx, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 return 1;
573}
574
575/* aio_put_req
576 * Returns true if this put was the last user of the kiocb,
577 * false if the request is still in use.
578 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800579int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
581 struct kioctx *ctx = req->ki_ctx;
582 int ret;
583 spin_lock_irq(&ctx->ctx_lock);
584 ret = __aio_put_req(ctx, req);
585 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 return ret;
587}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700588EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589
Adrian Bunkd5470b52008-04-29 00:58:57 -0700590static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591{
Jens Axboeabf137d2008-12-09 08:11:22 +0100592 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700593 struct kioctx *ctx, *ret = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
Jens Axboeabf137d2008-12-09 08:11:22 +0100595 rcu_read_lock();
596
Sasha Levinb67bfe02013-02-27 17:06:00 -0800597 hlist_for_each_entry_rcu(ctx, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800598 /*
599 * RCU protects us against accessing freed memory but
600 * we have to be careful not to get a reference when the
601 * reference count already dropped to 0 (ctx->dead test
602 * is unreliable because of races).
603 */
604 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700605 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 break;
607 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100608 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609
Jens Axboeabf137d2008-12-09 08:11:22 +0100610 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700611 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612}
613
614/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 * Queue up a kiocb to be retried. Assumes that the kiocb
616 * has already been marked as kicked, and places it on
617 * the retry run list for the corresponding ioctx, if it
618 * isn't already queued. Returns 1 if it actually queued
619 * the kiocb (to tell the caller to activate the work
620 * queue to process it), or 0, if it found that it was
621 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 */
623static inline int __queue_kicked_iocb(struct kiocb *iocb)
624{
625 struct kioctx *ctx = iocb->ki_ctx;
626
Zach Brownd00689a2005-11-13 16:07:34 -0800627 assert_spin_locked(&ctx->ctx_lock);
628
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 if (list_empty(&iocb->ki_run_list)) {
630 list_add_tail(&iocb->ki_run_list,
631 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 return 1;
633 }
634 return 0;
635}
636
637/* aio_run_iocb
638 * This is the core aio execution routine. It is
639 * invoked both for initial i/o submission and
640 * subsequent retries via the aio_kick_handler.
641 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200642 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 * as needed during processing.
644 *
645 * Calls the iocb retry method (already setup for the
646 * iocb on initial submission) for operation specific
647 * handling, but takes care of most of common retry
648 * execution details for a given iocb. The retry method
649 * needs to be non-blocking as far as possible, to avoid
650 * holding up other iocbs waiting to be serviced by the
651 * retry kernel thread.
652 *
653 * The trickier parts in this code have to do with
654 * ensuring that only one retry instance is in progress
655 * for a given iocb at any time. Providing that guarantee
656 * simplifies the coding of individual aio operations as
657 * it avoids various potential races.
658 */
659static ssize_t aio_run_iocb(struct kiocb *iocb)
660{
661 struct kioctx *ctx = iocb->ki_ctx;
662 ssize_t (*retry)(struct kiocb *);
663 ssize_t ret;
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 if (!(retry = iocb->ki_retry)) {
666 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
667 return 0;
668 }
669
670 /*
671 * We don't want the next retry iteration for this
672 * operation to start until this one has returned and
673 * updated the iocb state. However, wait_queue functions
674 * can trigger a kick_iocb from interrupt context in the
675 * meantime, indicating that data is available for the next
676 * iteration. We want to remember that and enable the
677 * next retry iteration _after_ we are through with
678 * this one.
679 *
680 * So, in order to be able to register a "kick", but
681 * prevent it from being queued now, we clear the kick
682 * flag, but make the kick code *think* that the iocb is
683 * still on the run list until we are actually done.
684 * When we are done with this iteration, we check if
685 * the iocb was kicked in the meantime and if so, queue
686 * it up afresh.
687 */
688
689 kiocbClearKicked(iocb);
690
691 /*
692 * This is so that aio_complete knows it doesn't need to
693 * pull the iocb off the run list (We can't just call
694 * INIT_LIST_HEAD because we don't want a kick_iocb to
695 * queue this on the run list yet)
696 */
697 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
698 spin_unlock_irq(&ctx->ctx_lock);
699
700 /* Quit retrying if the i/o has been cancelled */
701 if (kiocbIsCancelled(iocb)) {
702 ret = -EINTR;
703 aio_complete(iocb, ret, 0);
704 /* must not access the iocb after this */
705 goto out;
706 }
707
708 /*
709 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700710 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Jan Karaa0c42ba2010-09-22 13:05:03 -0700714 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
715 /*
716 * There's no easy way to restart the syscall since other AIO's
717 * may be already running. Just fail this IO with EINTR.
718 */
719 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
720 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
721 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700722 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700723 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724out:
725 spin_lock_irq(&ctx->ctx_lock);
726
727 if (-EIOCBRETRY == ret) {
728 /*
729 * OK, now that we are done with this iteration
730 * and know that there is more left to go,
731 * this is where we let go so that a subsequent
732 * "kick" can start the next iteration
733 */
734
735 /* will make __queue_kicked_iocb succeed from here on */
736 INIT_LIST_HEAD(&iocb->ki_run_list);
737 /* we must queue the next iteration ourselves, if it
738 * has already been kicked */
739 if (kiocbIsKicked(iocb)) {
740 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700741
742 /*
743 * __queue_kicked_iocb will always return 1 here, because
744 * iocb->ki_run_list is empty at this point so it should
745 * be safe to unconditionally queue the context into the
746 * work queue.
747 */
748 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 }
750 }
751 return ret;
752}
753
754/*
755 * __aio_run_iocbs:
756 * Process all pending retries queued on the ioctx
757 * run list.
758 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800759 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 */
761static int __aio_run_iocbs(struct kioctx *ctx)
762{
763 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700764 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765
Zach Brownd00689a2005-11-13 16:07:34 -0800766 assert_spin_locked(&ctx->ctx_lock);
767
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700768 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 while (!list_empty(&run_list)) {
770 iocb = list_entry(run_list.next, struct kiocb,
771 ki_run_list);
772 list_del(&iocb->ki_run_list);
773 /*
774 * Hold an extra reference while retrying i/o.
775 */
776 iocb->ki_users++; /* grab extra reference */
777 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800778 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 if (!list_empty(&ctx->run_list))
781 return 1;
782 return 0;
783}
784
785static void aio_queue_work(struct kioctx * ctx)
786{
787 unsigned long timeout;
788 /*
789 * if someone is waiting, get the work started right
790 * away, otherwise, use a longer delay
791 */
792 smp_mb();
793 if (waitqueue_active(&ctx->wait))
794 timeout = 1;
795 else
796 timeout = HZ/10;
797 queue_delayed_work(aio_wq, &ctx->wq, timeout);
798}
799
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800/*
Jeff Moyerd3486f82011-01-12 17:01:08 -0800801 * aio_run_all_iocbs:
802 * Process all pending retries queued on the ioctx
803 * run list, and keep running them until the list
804 * stays empty.
805 * Assumes it is operating within the aio issuer's mm context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 */
807static inline void aio_run_all_iocbs(struct kioctx *ctx)
808{
809 spin_lock_irq(&ctx->ctx_lock);
810 while (__aio_run_iocbs(ctx))
811 ;
812 spin_unlock_irq(&ctx->ctx_lock);
813}
814
815/*
816 * aio_kick_handler:
817 * Work queue handler triggered to process pending
818 * retries on an ioctx. Takes on the aio issuer's
819 * mm context before running the iocbs, so that
820 * copy_xxx_user operates on the issuer's address
821 * space.
822 * Run on aiod's context.
823 */
David Howells65f27f32006-11-22 14:55:48 +0000824static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825{
David Howells65f27f32006-11-22 14:55:48 +0000826 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800828 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 int requeue;
830
831 set_fs(USER_DS);
832 use_mm(ctx->mm);
833 spin_lock_irq(&ctx->ctx_lock);
834 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800835 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800837 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 set_fs(oldfs);
839 /*
Al Viro9fcf03d2012-03-13 22:06:28 -0400840 * we're in a worker thread already; no point using non-zero delay
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 */
842 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000843 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844}
845
846
847/*
848 * Called by kick_iocb to queue the kiocb for retry
849 * and if required activate the aio work queue to process
850 * it
851 */
Zach Brown998765e2005-09-30 11:58:54 -0700852static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853{
854 struct kioctx *ctx = iocb->ki_ctx;
855 unsigned long flags;
856 int run = 0;
857
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700859 /* set this inside the lock so that we can't race with aio_run_iocb()
860 * testing it and putting the iocb on the run list under the lock */
861 if (!kiocbTryKick(iocb))
862 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700864 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866}
867
868/*
869 * kick_iocb:
870 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800871 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 * The retry is usually executed by aio workqueue
873 * threads (See aio_kick_handler).
874 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800875void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876{
877 /* sync iocbs are easy: they can only ever be executing from a
878 * single context. */
879 if (is_sync_kiocb(iocb)) {
880 kiocbSetKicked(iocb);
881 wake_up_process(iocb->ki_obj.tsk);
882 return;
883 }
884
Zach Brown998765e2005-09-30 11:58:54 -0700885 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886}
887EXPORT_SYMBOL(kick_iocb);
888
889/* aio_complete
890 * Called when the io request on the given iocb is complete.
891 * Returns true if this is the last user of the request. The
892 * only other user of the request can be the cancellation code.
893 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800894int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895{
896 struct kioctx *ctx = iocb->ki_ctx;
897 struct aio_ring_info *info;
898 struct aio_ring *ring;
899 struct io_event *event;
900 unsigned long flags;
901 unsigned long tail;
902 int ret;
903
Zach Brown20dcae32005-11-13 16:07:33 -0800904 /*
905 * Special case handling for sync iocbs:
906 * - events go directly into the iocb for fast handling
907 * - the sync task with the iocb in its stack holds the single iocb
908 * ref, no other paths have a way to get another ref
909 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 */
911 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800912 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800914 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800916 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 }
918
919 info = &ctx->ring_info;
920
921 /* add a completion event to the ring buffer.
922 * must be done holding ctx->ctx_lock to prevent
923 * other code from messing with the tail
924 * pointer since we might be called from irq
925 * context.
926 */
927 spin_lock_irqsave(&ctx->ctx_lock, flags);
928
929 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
930 list_del_init(&iocb->ki_run_list);
931
932 /*
933 * cancelled requests don't get events, userland was given one
934 * when the event got cancelled.
935 */
936 if (kiocbIsCancelled(iocb))
937 goto put_rq;
938
Cong Wange8e3c3d2011-11-25 23:14:27 +0800939 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940
941 tail = info->tail;
Cong Wange8e3c3d2011-11-25 23:14:27 +0800942 event = aio_ring_event(info, tail);
Ken Chen4bf69b22005-05-01 08:59:15 -0700943 if (++tail >= info->nr)
944 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945
946 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
947 event->data = iocb->ki_user_data;
948 event->res = res;
949 event->res2 = res2;
950
951 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
952 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
953 res, res2);
954
955 /* after flagging the request as done, we
956 * must never even look at it again
957 */
958 smp_wmb(); /* make event visible before updating tail */
959
960 info->tail = tail;
961 ring->tail = tail;
962
Cong Wange8e3c3d2011-11-25 23:14:27 +0800963 put_aio_ring_event(event);
964 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965
966 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700967
968 /*
969 * Check if the user asked us to deliver the result through an
970 * eventfd. The eventfd_signal() function is safe to be called
971 * from IRQ context.
972 */
Davide Libenzi87c3a862009-03-18 17:04:19 -0700973 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700974 eventfd_signal(iocb->ki_eventfd, 1);
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976put_rq:
977 /* everything turned out well, dispose of the aiocb. */
978 ret = __aio_put_req(ctx, iocb);
979
Quentin Barnes6cb2a212008-03-19 17:00:39 -0700980 /*
981 * We have to order our ring_info tail store above and test
982 * of the wait list below outside the wait lock. This is
983 * like in wake_up_bit() where clearing a bit has to be
984 * ordered with the unlocked test.
985 */
986 smp_mb();
987
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 if (waitqueue_active(&ctx->wait))
989 wake_up(&ctx->wait);
990
Ken Chendee11c22007-02-03 01:13:45 -0800991 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 return ret;
993}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700994EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995
996/* aio_read_evt
997 * Pull an event off of the ioctx's event ring. Returns the number of
998 * events fetched (0 or 1 ;-)
999 * FIXME: make this use cmpxchg.
1000 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1001 */
1002static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1003{
1004 struct aio_ring_info *info = &ioctx->ring_info;
1005 struct aio_ring *ring;
1006 unsigned long head;
1007 int ret = 0;
1008
Cong Wange8e3c3d2011-11-25 23:14:27 +08001009 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1011 (unsigned long)ring->head, (unsigned long)ring->tail,
1012 (unsigned long)ring->nr);
1013
1014 if (ring->head == ring->tail)
1015 goto out;
1016
1017 spin_lock(&info->ring_lock);
1018
1019 head = ring->head % info->nr;
1020 if (head != ring->tail) {
Cong Wange8e3c3d2011-11-25 23:14:27 +08001021 struct io_event *evp = aio_ring_event(info, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 *ent = *evp;
1023 head = (head + 1) % info->nr;
1024 smp_mb(); /* finish reading the event before updatng the head */
1025 ring->head = head;
1026 ret = 1;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001027 put_aio_ring_event(evp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 }
1029 spin_unlock(&info->ring_lock);
1030
1031out:
Cong Wange8e3c3d2011-11-25 23:14:27 +08001032 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1034 (unsigned long)ring->head, (unsigned long)ring->tail);
1035 return ret;
1036}
1037
1038struct aio_timeout {
1039 struct timer_list timer;
1040 int timed_out;
1041 struct task_struct *p;
1042};
1043
1044static void timeout_func(unsigned long data)
1045{
1046 struct aio_timeout *to = (struct aio_timeout *)data;
1047
1048 to->timed_out = 1;
1049 wake_up_process(to->p);
1050}
1051
1052static inline void init_timeout(struct aio_timeout *to)
1053{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001054 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 to->timed_out = 0;
1056 to->p = current;
1057}
1058
1059static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1060 const struct timespec *ts)
1061{
1062 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1063 if (time_after(to->timer.expires, jiffies))
1064 add_timer(&to->timer);
1065 else
1066 to->timed_out = 1;
1067}
1068
1069static inline void clear_timeout(struct aio_timeout *to)
1070{
1071 del_singleshot_timer_sync(&to->timer);
1072}
1073
1074static int read_events(struct kioctx *ctx,
1075 long min_nr, long nr,
1076 struct io_event __user *event,
1077 struct timespec __user *timeout)
1078{
1079 long start_jiffies = jiffies;
1080 struct task_struct *tsk = current;
1081 DECLARE_WAITQUEUE(wait, tsk);
1082 int ret;
1083 int i = 0;
1084 struct io_event ent;
1085 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 int retry = 0;
1087
1088 /* needed to zero any padding within an entry (there shouldn't be
1089 * any, but C is fun!
1090 */
1091 memset(&ent, 0, sizeof(ent));
1092retry:
1093 ret = 0;
1094 while (likely(i < nr)) {
1095 ret = aio_read_evt(ctx, &ent);
1096 if (unlikely(ret <= 0))
1097 break;
1098
1099 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1100 ent.data, ent.obj, ent.res, ent.res2);
1101
1102 /* Could we split the check in two? */
1103 ret = -EFAULT;
1104 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1105 dprintk("aio: lost an event due to EFAULT.\n");
1106 break;
1107 }
1108 ret = 0;
1109
1110 /* Good, event copied to userland, update counts. */
1111 event ++;
1112 i ++;
1113 }
1114
1115 if (min_nr <= i)
1116 return i;
1117 if (ret)
1118 return ret;
1119
1120 /* End fast path */
1121
1122 /* racey check, but it gets redone */
1123 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1124 retry = 1;
1125 aio_run_all_iocbs(ctx);
1126 goto retry;
1127 }
1128
1129 init_timeout(&to);
1130 if (timeout) {
1131 struct timespec ts;
1132 ret = -EFAULT;
1133 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1134 goto out;
1135
1136 set_timeout(start_jiffies, &to, &ts);
1137 }
1138
1139 while (likely(i < nr)) {
1140 add_wait_queue_exclusive(&ctx->wait, &wait);
1141 do {
1142 set_task_state(tsk, TASK_INTERRUPTIBLE);
1143 ret = aio_read_evt(ctx, &ent);
1144 if (ret)
1145 break;
1146 if (min_nr <= i)
1147 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001148 if (unlikely(ctx->dead)) {
1149 ret = -EINVAL;
1150 break;
1151 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 if (to.timed_out) /* Only check after read evt */
1153 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001154 /* Try to only show up in io wait if there are ops
1155 * in flight */
1156 if (ctx->reqs_active)
1157 io_schedule();
1158 else
1159 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 if (signal_pending(tsk)) {
1161 ret = -EINTR;
1162 break;
1163 }
1164 /*ret = aio_read_evt(ctx, &ent);*/
1165 } while (1) ;
1166
1167 set_task_state(tsk, TASK_RUNNING);
1168 remove_wait_queue(&ctx->wait, &wait);
1169
1170 if (unlikely(ret <= 0))
1171 break;
1172
1173 ret = -EFAULT;
1174 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1175 dprintk("aio: lost an event due to EFAULT.\n");
1176 break;
1177 }
1178
1179 /* Good, event copied to userland, update counts. */
1180 event ++;
1181 i ++;
1182 }
1183
1184 if (timeout)
1185 clear_timeout(&to);
1186out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001187 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 return i ? i : ret;
1189}
1190
1191/* Take an ioctx and remove it from the list of ioctx's. Protects
1192 * against races with itself via ->dead.
1193 */
1194static void io_destroy(struct kioctx *ioctx)
1195{
1196 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 int was_dead;
1198
1199 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001200 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 was_dead = ioctx->dead;
1202 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001203 hlist_del_rcu(&ioctx->list);
1204 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205
1206 dprintk("aio_release(%p)\n", ioctx);
1207 if (likely(!was_dead))
1208 put_ioctx(ioctx); /* twice for the list */
1209
Al Viro06af1212012-03-20 16:26:24 -04001210 kill_ctx(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001211
1212 /*
1213 * Wake up any waiters. The setting of ctx->dead must be seen
1214 * by other CPUs at this point. Right now, we rely on the
1215 * locking done by the above calls to ensure this consistency.
1216 */
Roland Dreiere91f90b2011-03-22 16:35:10 -07001217 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218}
1219
1220/* sys_io_setup:
1221 * Create an aio_context capable of receiving at least nr_events.
1222 * ctxp must not point to an aio_context that already exists, and
1223 * must be initialized to 0 prior to the call. On successful
1224 * creation of the aio_context, *ctxp is filled in with the resulting
1225 * handle. May fail with -EINVAL if *ctxp is not initialized,
1226 * if the specified nr_events exceeds internal limits. May fail
1227 * with -EAGAIN if the specified nr_events exceeds the user's limit
1228 * of available events. May fail with -ENOMEM if insufficient kernel
1229 * resources are available. May fail with -EFAULT if an invalid
1230 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1231 * implemented.
1232 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001233SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234{
1235 struct kioctx *ioctx = NULL;
1236 unsigned long ctx;
1237 long ret;
1238
1239 ret = get_user(ctx, ctxp);
1240 if (unlikely(ret))
1241 goto out;
1242
1243 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001244 if (unlikely(ctx || nr_events == 0)) {
1245 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1246 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 goto out;
1248 }
1249
1250 ioctx = ioctx_alloc(nr_events);
1251 ret = PTR_ERR(ioctx);
1252 if (!IS_ERR(ioctx)) {
1253 ret = put_user(ioctx->user_id, ctxp);
Al Viroa2e18592012-03-20 16:27:57 -04001254 if (ret)
1255 io_destroy(ioctx);
1256 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 }
1258
1259out:
1260 return ret;
1261}
1262
1263/* sys_io_destroy:
1264 * Destroy the aio_context specified. May cancel any outstanding
1265 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001266 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 * is invalid.
1268 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001269SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270{
1271 struct kioctx *ioctx = lookup_ioctx(ctx);
1272 if (likely(NULL != ioctx)) {
1273 io_destroy(ioctx);
Al Viroa2e18592012-03-20 16:27:57 -04001274 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 return 0;
1276 }
1277 pr_debug("EINVAL: io_destroy: invalid context id\n");
1278 return -EINVAL;
1279}
1280
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001281static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1282{
1283 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1284
1285 BUG_ON(ret <= 0);
1286
1287 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1288 ssize_t this = min((ssize_t)iov->iov_len, ret);
1289 iov->iov_base += this;
1290 iov->iov_len -= this;
1291 iocb->ki_left -= this;
1292 ret -= this;
1293 if (iov->iov_len == 0) {
1294 iocb->ki_cur_seg++;
1295 iov++;
1296 }
1297 }
1298
1299 /* the caller should not have done more io than what fit in
1300 * the remaining iovecs */
1301 BUG_ON(ret > 0 && iocb->ki_left == 0);
1302}
1303
1304static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305{
1306 struct file *file = iocb->ki_filp;
1307 struct address_space *mapping = file->f_mapping;
1308 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001309 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1310 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001312 unsigned short opcode;
1313
1314 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1315 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1316 rw_op = file->f_op->aio_read;
1317 opcode = IOCB_CMD_PREADV;
1318 } else {
1319 rw_op = file->f_op->aio_write;
1320 opcode = IOCB_CMD_PWRITEV;
1321 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322
Rusty Russellc2ec6682008-02-08 04:20:15 -08001323 /* This matches the pread()/pwrite() logic */
1324 if (iocb->ki_pos < 0)
1325 return -EINVAL;
1326
Zach Brown897f15f2005-09-30 11:58:55 -07001327 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001328 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1329 iocb->ki_nr_segs - iocb->ki_cur_seg,
1330 iocb->ki_pos);
1331 if (ret > 0)
1332 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001333
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001334 /* retry all partial writes. retry partial reads as long as its a
1335 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001336 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001337 (opcode == IOCB_CMD_PWRITEV ||
1338 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
1340 /* This means we must have transferred all that we could */
1341 /* No need to retry anymore */
1342 if ((ret == 0) || (iocb->ki_left == 0))
1343 ret = iocb->ki_nbytes - iocb->ki_left;
1344
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001345 /* If we managed to write some out we return that, rather than
1346 * the eventual error. */
1347 if (opcode == IOCB_CMD_PWRITEV
1348 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1349 && iocb->ki_nbytes - iocb->ki_left)
1350 ret = iocb->ki_nbytes - iocb->ki_left;
1351
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 return ret;
1353}
1354
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355static ssize_t aio_fdsync(struct kiocb *iocb)
1356{
1357 struct file *file = iocb->ki_filp;
1358 ssize_t ret = -EINVAL;
1359
1360 if (file->f_op->aio_fsync)
1361 ret = file->f_op->aio_fsync(iocb, 1);
1362 return ret;
1363}
1364
1365static ssize_t aio_fsync(struct kiocb *iocb)
1366{
1367 struct file *file = iocb->ki_filp;
1368 ssize_t ret = -EINVAL;
1369
1370 if (file->f_op->aio_fsync)
1371 ret = file->f_op->aio_fsync(iocb, 0);
1372 return ret;
1373}
1374
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001375static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001376{
1377 ssize_t ret;
1378
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001379#ifdef CONFIG_COMPAT
1380 if (compat)
1381 ret = compat_rw_copy_check_uvector(type,
1382 (struct compat_iovec __user *)kiocb->ki_buf,
1383 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohac34ebb2012-05-31 16:26:42 -07001384 &kiocb->ki_iovec);
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001385 else
1386#endif
1387 ret = rw_copy_check_uvector(type,
1388 (struct iovec __user *)kiocb->ki_buf,
1389 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohac34ebb2012-05-31 16:26:42 -07001390 &kiocb->ki_iovec);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001391 if (ret < 0)
1392 goto out;
1393
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001394 ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret);
1395 if (ret < 0)
1396 goto out;
1397
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001398 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1399 kiocb->ki_cur_seg = 0;
1400 /* ki_nbytes/left now reflect bytes instead of segs */
1401 kiocb->ki_nbytes = ret;
1402 kiocb->ki_left = ret;
1403
1404 ret = 0;
1405out:
1406 return ret;
1407}
1408
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001409static ssize_t aio_setup_single_vector(int type, struct file * file, struct kiocb *kiocb)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001410{
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001411 int bytes;
1412
1413 bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left);
1414 if (bytes < 0)
1415 return bytes;
1416
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001417 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1418 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001419 kiocb->ki_iovec->iov_len = bytes;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001420 kiocb->ki_nr_segs = 1;
1421 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001422 return 0;
1423}
1424
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425/*
1426 * aio_setup_iocb:
1427 * Performs the initial checks and aio retry method
1428 * setup for the kiocb at the time of io submission.
1429 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001430static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431{
1432 struct file *file = kiocb->ki_filp;
1433 ssize_t ret = 0;
1434
1435 switch (kiocb->ki_opcode) {
1436 case IOCB_CMD_PREAD:
1437 ret = -EBADF;
1438 if (unlikely(!(file->f_mode & FMODE_READ)))
1439 break;
1440 ret = -EFAULT;
1441 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1442 kiocb->ki_left)))
1443 break;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001444 ret = aio_setup_single_vector(READ, file, kiocb);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001445 if (ret)
1446 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 ret = -EINVAL;
1448 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001449 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 break;
1451 case IOCB_CMD_PWRITE:
1452 ret = -EBADF;
1453 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1454 break;
1455 ret = -EFAULT;
1456 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1457 kiocb->ki_left)))
1458 break;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001459 ret = aio_setup_single_vector(WRITE, file, kiocb);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001460 if (ret)
1461 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 ret = -EINVAL;
1463 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001464 kiocb->ki_retry = aio_rw_vect_retry;
1465 break;
1466 case IOCB_CMD_PREADV:
1467 ret = -EBADF;
1468 if (unlikely(!(file->f_mode & FMODE_READ)))
1469 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001470 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001471 if (ret)
1472 break;
1473 ret = -EINVAL;
1474 if (file->f_op->aio_read)
1475 kiocb->ki_retry = aio_rw_vect_retry;
1476 break;
1477 case IOCB_CMD_PWRITEV:
1478 ret = -EBADF;
1479 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1480 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001481 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001482 if (ret)
1483 break;
1484 ret = -EINVAL;
1485 if (file->f_op->aio_write)
1486 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 break;
1488 case IOCB_CMD_FDSYNC:
1489 ret = -EINVAL;
1490 if (file->f_op->aio_fsync)
1491 kiocb->ki_retry = aio_fdsync;
1492 break;
1493 case IOCB_CMD_FSYNC:
1494 ret = -EINVAL;
1495 if (file->f_op->aio_fsync)
1496 kiocb->ki_retry = aio_fsync;
1497 break;
1498 default:
1499 dprintk("EINVAL: io_submit: no operation provided\n");
1500 ret = -EINVAL;
1501 }
1502
1503 if (!kiocb->ki_retry)
1504 return ret;
1505
1506 return 0;
1507}
1508
Adrian Bunkd5470b52008-04-29 00:58:57 -07001509static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer080d6762011-11-02 13:40:10 -07001510 struct iocb *iocb, struct kiocb_batch *batch,
1511 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512{
1513 struct kiocb *req;
1514 struct file *file;
1515 ssize_t ret;
1516
1517 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001518 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 pr_debug("EINVAL: io_submit: reserve field set\n");
1520 return -EINVAL;
1521 }
1522
1523 /* prevent overflows */
1524 if (unlikely(
1525 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1526 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1527 ((ssize_t)iocb->aio_nbytes < 0)
1528 )) {
1529 pr_debug("EINVAL: io_submit: overflow check\n");
1530 return -EINVAL;
1531 }
1532
1533 file = fget(iocb->aio_fildes);
1534 if (unlikely(!file))
1535 return -EBADF;
1536
Jeff Moyer080d6762011-11-02 13:40:10 -07001537 req = aio_get_req(ctx, batch); /* returns with 2 references to req */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 if (unlikely(!req)) {
1539 fput(file);
1540 return -EAGAIN;
1541 }
Yan Zheng87e28312007-10-08 12:16:20 -07001542 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001543 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1544 /*
1545 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1546 * instance of the file* now. The file descriptor must be
1547 * an eventfd() fd, and will be signaled for each completed
1548 * event using the eventfd_signal() function.
1549 */
Davide Libenzi13389012009-06-30 11:41:11 -07001550 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001551 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001552 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001553 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001554 goto out_put_req;
1555 }
1556 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
Ken Chen212079c2005-05-01 08:59:15 -07001558 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559 if (unlikely(ret)) {
1560 dprintk("EFAULT: aio_key\n");
1561 goto out_put_req;
1562 }
1563
1564 req->ki_obj.user = user_iocb;
1565 req->ki_user_data = iocb->aio_data;
1566 req->ki_pos = iocb->aio_offset;
1567
1568 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1569 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1570 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001572 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573
1574 if (ret)
1575 goto out_put_req;
1576
1577 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001578 /*
1579 * We could have raced with io_destroy() and are currently holding a
1580 * reference to ctx which should be destroyed. We cannot submit IO
1581 * since ctx gets freed as soon as io_submit() puts its reference. The
1582 * check here is reliable: io_destroy() sets ctx->dead before waiting
1583 * for outstanding IO and the barrier between these two is realized by
1584 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1585 * increment ctx->reqs_active before checking for ctx->dead and the
1586 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1587 * don't see ctx->dead set here, io_destroy() waits for our IO to
1588 * finish.
1589 */
1590 if (ctx->dead) {
1591 spin_unlock_irq(&ctx->ctx_lock);
1592 ret = -EINVAL;
1593 goto out_put_req;
1594 }
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001595 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001596 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001597 /* drain the run list */
1598 while (__aio_run_iocbs(ctx))
1599 ;
1600 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001602
Linus Torvalds1da177e2005-04-16 15:20:36 -07001603 aio_put_req(req); /* drop extra ref to req */
1604 return 0;
1605
1606out_put_req:
1607 aio_put_req(req); /* drop extra ref to req */
1608 aio_put_req(req); /* drop i/o ref to req */
1609 return ret;
1610}
1611
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001612long do_io_submit(aio_context_t ctx_id, long nr,
1613 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614{
1615 struct kioctx *ctx;
1616 long ret = 0;
Jeff Moyer080d6762011-11-02 13:40:10 -07001617 int i = 0;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001618 struct blk_plug plug;
Jeff Moyer080d6762011-11-02 13:40:10 -07001619 struct kiocb_batch batch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620
1621 if (unlikely(nr < 0))
1622 return -EINVAL;
1623
Jeff Moyer75e1c702010-09-10 14:16:00 -07001624 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1625 nr = LONG_MAX/sizeof(*iocbpp);
1626
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1628 return -EFAULT;
1629
1630 ctx = lookup_ioctx(ctx_id);
1631 if (unlikely(!ctx)) {
1632 pr_debug("EINVAL: io_submit: invalid context id\n");
1633 return -EINVAL;
1634 }
1635
Jeff Moyer080d6762011-11-02 13:40:10 -07001636 kiocb_batch_init(&batch, nr);
1637
Shaohua Li9f5b9422010-07-01 07:55:01 +02001638 blk_start_plug(&plug);
1639
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 /*
1641 * AKPM: should this return a partial result if some of the IOs were
1642 * successfully submitted?
1643 */
1644 for (i=0; i<nr; i++) {
1645 struct iocb __user *user_iocb;
1646 struct iocb tmp;
1647
1648 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1649 ret = -EFAULT;
1650 break;
1651 }
1652
1653 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1654 ret = -EFAULT;
1655 break;
1656 }
1657
Jeff Moyer080d6762011-11-02 13:40:10 -07001658 ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 if (ret)
1660 break;
1661 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001662 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663
Gleb Natapov69e47472012-01-08 17:07:28 +02001664 kiocb_batch_free(ctx, &batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665 put_ioctx(ctx);
1666 return i ? i : ret;
1667}
1668
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001669/* sys_io_submit:
1670 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1671 * the number of iocbs queued. May return -EINVAL if the aio_context
1672 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1673 * *iocbpp[0] is not properly initialized, if the operation specified
1674 * is invalid for the file descriptor in the iocb. May fail with
1675 * -EFAULT if any of the data structures point to invalid data. May
1676 * fail with -EBADF if the file descriptor specified in the first
1677 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1678 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1679 * fail with -ENOSYS if not implemented.
1680 */
1681SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1682 struct iocb __user * __user *, iocbpp)
1683{
1684 return do_io_submit(ctx_id, nr, iocbpp, 0);
1685}
1686
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687/* lookup_kiocb
1688 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001690static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1691 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692{
1693 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001694
1695 assert_spin_locked(&ctx->ctx_lock);
1696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 /* TODO: use a hash or array, this sucks. */
1698 list_for_each(pos, &ctx->active_reqs) {
1699 struct kiocb *kiocb = list_kiocb(pos);
1700 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1701 return kiocb;
1702 }
1703 return NULL;
1704}
1705
1706/* sys_io_cancel:
1707 * Attempts to cancel an iocb previously passed to io_submit. If
1708 * the operation is successfully cancelled, the resulting event is
1709 * copied into the memory pointed to by result without being placed
1710 * into the completion queue and 0 is returned. May fail with
1711 * -EFAULT if any of the data structures pointed to are invalid.
1712 * May fail with -EINVAL if aio_context specified by ctx_id is
1713 * invalid. May fail with -EAGAIN if the iocb specified was not
1714 * cancelled. Will fail with -ENOSYS if not implemented.
1715 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001716SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1717 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718{
1719 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1720 struct kioctx *ctx;
1721 struct kiocb *kiocb;
1722 u32 key;
1723 int ret;
1724
1725 ret = get_user(key, &iocb->aio_key);
1726 if (unlikely(ret))
1727 return -EFAULT;
1728
1729 ctx = lookup_ioctx(ctx_id);
1730 if (unlikely(!ctx))
1731 return -EINVAL;
1732
1733 spin_lock_irq(&ctx->ctx_lock);
1734 ret = -EAGAIN;
1735 kiocb = lookup_kiocb(ctx, iocb, key);
1736 if (kiocb && kiocb->ki_cancel) {
1737 cancel = kiocb->ki_cancel;
1738 kiocb->ki_users ++;
1739 kiocbSetCancelled(kiocb);
1740 } else
1741 cancel = NULL;
1742 spin_unlock_irq(&ctx->ctx_lock);
1743
1744 if (NULL != cancel) {
1745 struct io_event tmp;
1746 pr_debug("calling cancel\n");
1747 memset(&tmp, 0, sizeof(tmp));
1748 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1749 tmp.data = kiocb->ki_user_data;
1750 ret = cancel(kiocb, &tmp);
1751 if (!ret) {
1752 /* Cancellation succeeded -- copy the result
1753 * into the user's buffer.
1754 */
1755 if (copy_to_user(result, &tmp, sizeof(tmp)))
1756 ret = -EFAULT;
1757 }
1758 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001759 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760
1761 put_ioctx(ctx);
1762
1763 return ret;
1764}
1765
1766/* io_getevents:
1767 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001768 * the completion queue for the aio_context specified by ctx_id. If
1769 * it succeeds, the number of read events is returned. May fail with
1770 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1771 * out of range, if timeout is out of range. May fail with -EFAULT
1772 * if any of the memory specified is invalid. May return 0 or
1773 * < min_nr if the timeout specified by timeout has elapsed
1774 * before sufficient events are available, where timeout == NULL
1775 * specifies an infinite timeout. Note that the timeout pointed to by
1776 * timeout is relative and will be updated if not NULL and the
1777 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001779SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1780 long, min_nr,
1781 long, nr,
1782 struct io_event __user *, events,
1783 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784{
1785 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1786 long ret = -EINVAL;
1787
1788 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001789 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 ret = read_events(ioctx, min_nr, nr, events, timeout);
1791 put_ioctx(ioctx);
1792 }
1793
Roland McGrath598af052008-04-10 15:38:45 -07001794 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 return ret;
1796}