blob: 67a6db3e1b6f83677009d2323c54dccd38dea63d [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
Al Viro936af152012-04-20 21:49:41 -040095 if (info->mmap_size) {
96 BUG_ON(ctx->mm != current->mm);
Al Virobfce2812012-04-20 21:57:04 -040097 vm_munmap(info->mmap_base, info->mmap_size);
Al Viro936af152012-04-20 21:49:41 -040098 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 if (info->ring_pages && info->ring_pages != info->internal_pages)
101 kfree(info->ring_pages);
102 info->ring_pages = NULL;
103 info->nr = 0;
104}
105
106static int aio_setup_ring(struct kioctx *ctx)
107{
108 struct aio_ring *ring;
109 struct aio_ring_info *info = &ctx->ring_info;
110 unsigned nr_events = ctx->max_reqs;
111 unsigned long size;
112 int nr_pages;
113
114 /* Compensate for the ring buffer's head/tail overlap entry */
115 nr_events += 2; /* 1 is required, 2 for good luck */
116
117 size = sizeof(struct aio_ring);
118 size += sizeof(struct io_event) * nr_events;
119 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
120
121 if (nr_pages < 0)
122 return -EINVAL;
123
124 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
125
126 info->nr = 0;
127 info->ring_pages = info->internal_pages;
128 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800129 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 if (!info->ring_pages)
131 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 }
133
134 info->mmap_size = nr_pages * PAGE_SIZE;
135 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
136 down_write(&ctx->mm->mmap_sem);
137 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
Robert P. J. Daye10a4432007-02-10 01:42:56 -0800138 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 0);
140 if (IS_ERR((void *)info->mmap_base)) {
141 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 info->mmap_size = 0;
143 aio_free_ring(ctx);
144 return -EAGAIN;
145 }
146
147 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
148 info->nr_pages = get_user_pages(current, ctx->mm,
149 info->mmap_base, nr_pages,
150 1, 0, info->ring_pages, NULL);
151 up_write(&ctx->mm->mmap_sem);
152
153 if (unlikely(info->nr_pages != nr_pages)) {
154 aio_free_ring(ctx);
155 return -EAGAIN;
156 }
157
158 ctx->user_id = info->mmap_base;
159
160 info->nr = nr_events; /* trusted copy */
161
Cong Wange8e3c3d2011-11-25 23:14:27 +0800162 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 ring->nr = nr_events; /* user copy */
164 ring->id = ctx->user_id;
165 ring->head = ring->tail = 0;
166 ring->magic = AIO_RING_MAGIC;
167 ring->compat_features = AIO_RING_COMPAT_FEATURES;
168 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
169 ring->header_length = sizeof(struct aio_ring);
Cong Wange8e3c3d2011-11-25 23:14:27 +0800170 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172 return 0;
173}
174
175
176/* aio_ring_event: returns a pointer to the event at the given index from
Cong Wange8e3c3d2011-11-25 23:14:27 +0800177 * kmap_atomic(). Release the pointer with put_aio_ring_event();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 */
179#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
180#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
181#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
182
Cong Wange8e3c3d2011-11-25 23:14:27 +0800183#define aio_ring_event(info, nr) ({ \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
185 struct io_event *__event; \
186 __event = kmap_atomic( \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800187 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 __event += pos % AIO_EVENTS_PER_PAGE; \
189 __event; \
190})
191
Cong Wange8e3c3d2011-11-25 23:14:27 +0800192#define put_aio_ring_event(event) do { \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 struct io_event *__event = (event); \
194 (void)__event; \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800195 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196} while(0)
197
Jens Axboeabf137d2008-12-09 08:11:22 +0100198static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700199{
Jens Axboeabf137d2008-12-09 08:11:22 +0100200 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700201 kmem_cache_free(kioctx_cachep, ctx);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700202}
203
Jens Axboeabf137d2008-12-09 08:11:22 +0100204/* __put_ioctx
205 * Called when the last user of an aio context has gone away,
206 * and the struct needs to be freed.
207 */
208static void __put_ioctx(struct kioctx *ctx)
209{
Al Viro2dd542b2012-03-10 23:10:35 -0500210 unsigned nr_events = ctx->max_reqs;
Jens Axboeabf137d2008-12-09 08:11:22 +0100211 BUG_ON(ctx->reqs_active);
212
Al Virobf507222012-03-11 00:58:40 -0500213 cancel_delayed_work_sync(&ctx->wq);
Jens Axboeabf137d2008-12-09 08:11:22 +0100214 aio_free_ring(ctx);
215 mmdrop(ctx->mm);
216 ctx->mm = NULL;
Al Viro2dd542b2012-03-10 23:10:35 -0500217 if (nr_events) {
218 spin_lock(&aio_nr_lock);
219 BUG_ON(aio_nr - nr_events > aio_nr);
220 aio_nr -= nr_events;
221 spin_unlock(&aio_nr_lock);
222 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100223 pr_debug("__put_ioctx: freeing %p\n", ctx);
224 call_rcu(&ctx->rcu_head, ctx_rcu_free);
225}
226
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800227static inline int try_get_ioctx(struct kioctx *kioctx)
228{
229 return atomic_inc_not_zero(&kioctx->users);
230}
231
232static inline void put_ioctx(struct kioctx *kioctx)
233{
234 BUG_ON(atomic_read(&kioctx->users) <= 0);
235 if (unlikely(atomic_dec_and_test(&kioctx->users)))
236 __put_ioctx(kioctx);
237}
Adrian Bunkd5470b52008-04-29 00:58:57 -0700238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239/* ioctx_alloc
240 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
241 */
242static struct kioctx *ioctx_alloc(unsigned nr_events)
243{
244 struct mm_struct *mm;
245 struct kioctx *ctx;
Al Viroe23754f2012-03-06 14:33:22 -0500246 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
248 /* Prevent overflows */
249 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
250 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
251 pr_debug("ENOMEM: nr_events too high\n");
252 return ERR_PTR(-EINVAL);
253 }
254
Al Viro2dd542b2012-03-10 23:10:35 -0500255 if (!nr_events || (unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 return ERR_PTR(-EAGAIN);
257
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800258 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 if (!ctx)
260 return ERR_PTR(-ENOMEM);
261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 ctx->max_reqs = nr_events;
263 mm = ctx->mm = current->mm;
264 atomic_inc(&mm->mm_count);
265
Al Viro86b62a22012-03-07 05:16:35 +0000266 atomic_set(&ctx->users, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 spin_lock_init(&ctx->ctx_lock);
268 spin_lock_init(&ctx->ring_info.ring_lock);
269 init_waitqueue_head(&ctx->wait);
270
271 INIT_LIST_HEAD(&ctx->active_reqs);
272 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000273 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275 if (aio_setup_ring(ctx) < 0)
276 goto out_freectx;
277
278 /* limit the number of system wide aios */
Al Viro9fa1cb32012-03-10 23:14:05 -0500279 spin_lock(&aio_nr_lock);
Al Viro2dd542b2012-03-10 23:10:35 -0500280 if (aio_nr + nr_events > aio_max_nr ||
281 aio_nr + nr_events < aio_nr) {
Al Viro9fa1cb32012-03-10 23:14:05 -0500282 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 goto out_cleanup;
Al Viro2dd542b2012-03-10 23:10:35 -0500284 }
285 aio_nr += ctx->max_reqs;
Al Viro9fa1cb32012-03-10 23:14:05 -0500286 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Jeff Moyer39fa0032008-04-29 01:03:48 -0700288 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100289 spin_lock(&mm->ioctx_lock);
290 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
291 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
293 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
294 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
295 return ctx;
296
297out_cleanup:
Al Viroe23754f2012-03-06 14:33:22 -0500298 err = -EAGAIN;
299 aio_free_ring(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300out_freectx:
301 mmdrop(mm);
302 kmem_cache_free(kioctx_cachep, ctx);
Al Viroe23754f2012-03-06 14:33:22 -0500303 dprintk("aio: error allocating ioctx %d\n", err);
304 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305}
306
Al Viro06af1212012-03-20 16:26:24 -0400307/* kill_ctx
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 * Cancels all outstanding aio requests on an aio context. Used
309 * when the processes owning a context have all exited to encourage
310 * the rapid destruction of the kioctx.
311 */
Al Viro06af1212012-03-20 16:26:24 -0400312static void kill_ctx(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313{
314 int (*cancel)(struct kiocb *, struct io_event *);
Al Viro06af1212012-03-20 16:26:24 -0400315 struct task_struct *tsk = current;
316 DECLARE_WAITQUEUE(wait, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 struct io_event res;
Al Viro06af1212012-03-20 16:26:24 -0400318
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 spin_lock_irq(&ctx->ctx_lock);
320 ctx->dead = 1;
321 while (!list_empty(&ctx->active_reqs)) {
322 struct list_head *pos = ctx->active_reqs.next;
323 struct kiocb *iocb = list_kiocb(pos);
324 list_del_init(&iocb->ki_list);
325 cancel = iocb->ki_cancel;
326 kiocbSetCancelled(iocb);
327 if (cancel) {
328 iocb->ki_users++;
329 spin_unlock_irq(&ctx->ctx_lock);
330 cancel(iocb, &res);
331 spin_lock_irq(&ctx->ctx_lock);
332 }
333 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800336 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337
338 add_wait_queue(&ctx->wait, &wait);
339 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
340 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800341 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700342 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800344 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 }
346 __set_task_state(tsk, TASK_RUNNING);
347 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800348
349out:
350 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351}
352
353/* wait_on_sync_kiocb:
354 * Waits on the given sync kiocb to complete.
355 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800356ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357{
358 while (iocb->ki_users) {
359 set_current_state(TASK_UNINTERRUPTIBLE);
360 if (!iocb->ki_users)
361 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700362 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 }
364 __set_current_state(TASK_RUNNING);
365 return iocb->ki_user_data;
366}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700367EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
369/* exit_aio: called when the last user of mm goes away. At this point,
370 * there is no way for any new requests to be submited or any of the
371 * io_* syscalls to be called on the context. However, there may be
372 * outstanding requests which hold references to the context; as they
373 * go away, they will call put_ioctx and release any pinned memory
374 * associated with the request (held via struct page * references).
375 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800376void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377{
Jens Axboeabf137d2008-12-09 08:11:22 +0100378 struct kioctx *ctx;
379
380 while (!hlist_empty(&mm->ioctx_list)) {
381 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
382 hlist_del_rcu(&ctx->list);
383
Al Viro06af1212012-03-20 16:26:24 -0400384 kill_ctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385
386 if (1 != atomic_read(&ctx->users))
387 printk(KERN_DEBUG
388 "exit_aio:ioctx still alive: %d %d %d\n",
389 atomic_read(&ctx->users), ctx->dead,
390 ctx->reqs_active);
Al Viro936af152012-04-20 21:49:41 -0400391 /*
392 * We don't need to bother with munmap() here -
393 * exit_mmap(mm) is coming and it'll unmap everything.
394 * Since aio_free_ring() uses non-zero ->mmap_size
395 * as indicator that it needs to unmap the area,
396 * just set it to 0; aio_free_ring() is the only
397 * place that uses ->mmap_size, so it's safe.
398 * That way we get all munmap done to current->mm -
399 * all other callers have ctx->mm == current->mm.
400 */
401 ctx->ring_info.mmap_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 }
404}
405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406/* aio_get_req
407 * Allocate a slot for an aio request. Increments the users count
408 * of the kioctx so that the kioctx stays around until all requests are
409 * complete. Returns NULL if no requests are free.
410 *
411 * Returns with kiocb->users set to 2. The io submit code path holds
412 * an extra reference while submitting the i/o.
413 * This prevents races between the aio code path referencing the
414 * req (after submitting it) and aio_complete() freeing the req.
415 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800416static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417{
418 struct kiocb *req = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419
420 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
421 if (unlikely(!req))
422 return NULL;
423
Zach Brown4faa5282005-10-17 16:43:33 -0700424 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 req->ki_users = 2;
426 req->ki_key = 0;
427 req->ki_ctx = ctx;
428 req->ki_cancel = NULL;
429 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 req->ki_dtor = NULL;
431 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700432 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700434 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 return req;
437}
438
Jeff Moyer080d6762011-11-02 13:40:10 -0700439/*
440 * struct kiocb's are allocated in batches to reduce the number of
441 * times the ctx lock is acquired and released.
442 */
443#define KIOCB_BATCH_SIZE 32L
444struct kiocb_batch {
445 struct list_head head;
446 long count; /* number of requests left to allocate */
447};
448
449static void kiocb_batch_init(struct kiocb_batch *batch, long total)
450{
451 INIT_LIST_HEAD(&batch->head);
452 batch->count = total;
453}
454
Gleb Natapov69e47472012-01-08 17:07:28 +0200455static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
Jeff Moyer080d6762011-11-02 13:40:10 -0700456{
457 struct kiocb *req, *n;
458
Gleb Natapov69e47472012-01-08 17:07:28 +0200459 if (list_empty(&batch->head))
460 return;
461
462 spin_lock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700463 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
464 list_del(&req->ki_batch);
Gleb Natapov69e47472012-01-08 17:07:28 +0200465 list_del(&req->ki_list);
Jeff Moyer080d6762011-11-02 13:40:10 -0700466 kmem_cache_free(kiocb_cachep, req);
Gleb Natapov69e47472012-01-08 17:07:28 +0200467 ctx->reqs_active--;
Jeff Moyer080d6762011-11-02 13:40:10 -0700468 }
Jeff Moyer880641b2012-03-05 14:59:12 -0800469 if (unlikely(!ctx->reqs_active && ctx->dead))
470 wake_up_all(&ctx->wait);
Gleb Natapov69e47472012-01-08 17:07:28 +0200471 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700472}
473
474/*
475 * Allocate a batch of kiocbs. This avoids taking and dropping the
476 * context lock a lot during setup.
477 */
478static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
479{
480 unsigned short allocated, to_alloc;
481 long avail;
482 bool called_fput = false;
483 struct kiocb *req, *n;
484 struct aio_ring *ring;
485
486 to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
487 for (allocated = 0; allocated < to_alloc; allocated++) {
488 req = __aio_get_req(ctx);
489 if (!req)
490 /* allocation failed, go with what we've got */
491 break;
492 list_add(&req->ki_batch, &batch->head);
493 }
494
495 if (allocated == 0)
496 goto out;
497
498retry:
499 spin_lock_irq(&ctx->ctx_lock);
500 ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
501
502 avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active;
503 BUG_ON(avail < 0);
504 if (avail == 0 && !called_fput) {
505 /*
506 * Handle a potential starvation case. It is possible that
507 * we hold the last reference on a struct file, causing us
508 * to delay the final fput to non-irq context. In this case,
509 * ctx->reqs_active is artificially high. Calling the fput
510 * routine here may free up a slot in the event completion
511 * ring, allowing this allocation to succeed.
512 */
513 kunmap_atomic(ring);
514 spin_unlock_irq(&ctx->ctx_lock);
515 aio_fput_routine(NULL);
516 called_fput = true;
517 goto retry;
518 }
519
520 if (avail < allocated) {
521 /* Trim back the number of requests. */
522 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
523 list_del(&req->ki_batch);
524 kmem_cache_free(kiocb_cachep, req);
525 if (--allocated <= avail)
526 break;
527 }
528 }
529
530 batch->count -= allocated;
531 list_for_each_entry(req, &batch->head, ki_batch) {
532 list_add(&req->ki_list, &ctx->active_reqs);
533 ctx->reqs_active++;
534 }
535
536 kunmap_atomic(ring);
537 spin_unlock_irq(&ctx->ctx_lock);
538
539out:
540 return allocated;
541}
542
543static inline struct kiocb *aio_get_req(struct kioctx *ctx,
544 struct kiocb_batch *batch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545{
546 struct kiocb *req;
Jeff Moyer080d6762011-11-02 13:40:10 -0700547
548 if (list_empty(&batch->head))
549 if (kiocb_batch_refill(ctx, batch) == 0)
550 return NULL;
551 req = list_first_entry(&batch->head, struct kiocb, ki_batch);
552 list_del(&req->ki_batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 return req;
554}
555
556static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
557{
Zach Brownd00689a2005-11-13 16:07:34 -0800558 assert_spin_locked(&ctx->ctx_lock);
559
Davide Libenzi13389012009-06-30 11:41:11 -0700560 if (req->ki_eventfd != NULL)
561 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 if (req->ki_dtor)
563 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700564 if (req->ki_iovec != &req->ki_inline_vec)
565 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 kmem_cache_free(kiocb_cachep, req);
567 ctx->reqs_active--;
568
569 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700570 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571}
572
David Howells65f27f32006-11-22 14:55:48 +0000573static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574{
575 spin_lock_irq(&fput_lock);
576 while (likely(!list_empty(&fput_head))) {
577 struct kiocb *req = list_kiocb(fput_head.next);
578 struct kioctx *ctx = req->ki_ctx;
579
580 list_del(&req->ki_list);
581 spin_unlock_irq(&fput_lock);
582
Davide Libenzi87c3a862009-03-18 17:04:19 -0700583 /* Complete the fput(s) */
584 if (req->ki_filp != NULL)
Al Virod7065da2010-05-26 15:13:55 -0400585 fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587 /* Link the iocb into the context's free list */
Al Viroc7b28552012-03-08 17:51:19 +0000588 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 spin_lock_irq(&ctx->ctx_lock);
590 really_put_req(ctx, req);
Al Viroc7b28552012-03-08 17:51:19 +0000591 /*
592 * at that point ctx might've been killed, but actual
593 * freeing is RCU'd
594 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 spin_unlock_irq(&ctx->ctx_lock);
Al Viroc7b28552012-03-08 17:51:19 +0000596 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 spin_lock_irq(&fput_lock);
599 }
600 spin_unlock_irq(&fput_lock);
601}
602
603/* __aio_put_req
604 * Returns true if this put was the last user of the request.
605 */
606static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
607{
Al Viro516e0cc2008-07-26 00:39:17 -0400608 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
609 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
Zach Brownd00689a2005-11-13 16:07:34 -0800611 assert_spin_locked(&ctx->ctx_lock);
612
Davide Libenzi87c3a862009-03-18 17:04:19 -0700613 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100614 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 if (likely(req->ki_users))
616 return 0;
617 list_del(&req->ki_list); /* remove from active_reqs */
618 req->ki_cancel = NULL;
619 req->ki_retry = NULL;
620
Davide Libenzi87c3a862009-03-18 17:04:19 -0700621 /*
622 * Try to optimize the aio and eventfd file* puts, by avoiding to
Al Virod7065da2010-05-26 15:13:55 -0400623 * schedule work in case it is not final fput() time. In normal cases,
Davide Libenzi87c3a862009-03-18 17:04:19 -0700624 * we would not be holding the last reference to the file*, so
625 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 */
Al Virod7065da2010-05-26 15:13:55 -0400627 if (unlikely(!fput_atomic(req->ki_filp))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 spin_lock(&fput_lock);
629 list_add(&req->ki_list, &fput_head);
630 spin_unlock(&fput_lock);
Tejun Heod37adaa2011-01-26 17:42:27 +0100631 schedule_work(&fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700632 } else {
633 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700635 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 return 1;
637}
638
639/* aio_put_req
640 * Returns true if this put was the last user of the kiocb,
641 * false if the request is still in use.
642 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800643int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644{
645 struct kioctx *ctx = req->ki_ctx;
646 int ret;
647 spin_lock_irq(&ctx->ctx_lock);
648 ret = __aio_put_req(ctx, req);
649 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 return ret;
651}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700652EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
Adrian Bunkd5470b52008-04-29 00:58:57 -0700654static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655{
Jens Axboeabf137d2008-12-09 08:11:22 +0100656 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700657 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100658 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
Jens Axboeabf137d2008-12-09 08:11:22 +0100660 rcu_read_lock();
661
662 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d2011-02-25 14:44:26 -0800663 /*
664 * RCU protects us against accessing freed memory but
665 * we have to be careful not to get a reference when the
666 * reference count already dropped to 0 (ctx->dead test
667 * is unreliable because of races).
668 */
669 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700670 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 break;
672 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100673 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674
Jens Axboeabf137d2008-12-09 08:11:22 +0100675 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700676 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677}
678
679/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 * Queue up a kiocb to be retried. Assumes that the kiocb
681 * has already been marked as kicked, and places it on
682 * the retry run list for the corresponding ioctx, if it
683 * isn't already queued. Returns 1 if it actually queued
684 * the kiocb (to tell the caller to activate the work
685 * queue to process it), or 0, if it found that it was
686 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 */
688static inline int __queue_kicked_iocb(struct kiocb *iocb)
689{
690 struct kioctx *ctx = iocb->ki_ctx;
691
Zach Brownd00689a2005-11-13 16:07:34 -0800692 assert_spin_locked(&ctx->ctx_lock);
693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 if (list_empty(&iocb->ki_run_list)) {
695 list_add_tail(&iocb->ki_run_list,
696 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 return 1;
698 }
699 return 0;
700}
701
702/* aio_run_iocb
703 * This is the core aio execution routine. It is
704 * invoked both for initial i/o submission and
705 * subsequent retries via the aio_kick_handler.
706 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200707 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 * as needed during processing.
709 *
710 * Calls the iocb retry method (already setup for the
711 * iocb on initial submission) for operation specific
712 * handling, but takes care of most of common retry
713 * execution details for a given iocb. The retry method
714 * needs to be non-blocking as far as possible, to avoid
715 * holding up other iocbs waiting to be serviced by the
716 * retry kernel thread.
717 *
718 * The trickier parts in this code have to do with
719 * ensuring that only one retry instance is in progress
720 * for a given iocb at any time. Providing that guarantee
721 * simplifies the coding of individual aio operations as
722 * it avoids various potential races.
723 */
724static ssize_t aio_run_iocb(struct kiocb *iocb)
725{
726 struct kioctx *ctx = iocb->ki_ctx;
727 ssize_t (*retry)(struct kiocb *);
728 ssize_t ret;
729
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 if (!(retry = iocb->ki_retry)) {
731 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
732 return 0;
733 }
734
735 /*
736 * We don't want the next retry iteration for this
737 * operation to start until this one has returned and
738 * updated the iocb state. However, wait_queue functions
739 * can trigger a kick_iocb from interrupt context in the
740 * meantime, indicating that data is available for the next
741 * iteration. We want to remember that and enable the
742 * next retry iteration _after_ we are through with
743 * this one.
744 *
745 * So, in order to be able to register a "kick", but
746 * prevent it from being queued now, we clear the kick
747 * flag, but make the kick code *think* that the iocb is
748 * still on the run list until we are actually done.
749 * When we are done with this iteration, we check if
750 * the iocb was kicked in the meantime and if so, queue
751 * it up afresh.
752 */
753
754 kiocbClearKicked(iocb);
755
756 /*
757 * This is so that aio_complete knows it doesn't need to
758 * pull the iocb off the run list (We can't just call
759 * INIT_LIST_HEAD because we don't want a kick_iocb to
760 * queue this on the run list yet)
761 */
762 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
763 spin_unlock_irq(&ctx->ctx_lock);
764
765 /* Quit retrying if the i/o has been cancelled */
766 if (kiocbIsCancelled(iocb)) {
767 ret = -EINTR;
768 aio_complete(iocb, ret, 0);
769 /* must not access the iocb after this */
770 goto out;
771 }
772
773 /*
774 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700775 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778
Jan Karaa0c42ba2010-09-22 13:05:03 -0700779 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
780 /*
781 * There's no easy way to restart the syscall since other AIO's
782 * may be already running. Just fail this IO with EINTR.
783 */
784 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
785 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
786 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700787 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700788 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789out:
790 spin_lock_irq(&ctx->ctx_lock);
791
792 if (-EIOCBRETRY == ret) {
793 /*
794 * OK, now that we are done with this iteration
795 * and know that there is more left to go,
796 * this is where we let go so that a subsequent
797 * "kick" can start the next iteration
798 */
799
800 /* will make __queue_kicked_iocb succeed from here on */
801 INIT_LIST_HEAD(&iocb->ki_run_list);
802 /* we must queue the next iteration ourselves, if it
803 * has already been kicked */
804 if (kiocbIsKicked(iocb)) {
805 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700806
807 /*
808 * __queue_kicked_iocb will always return 1 here, because
809 * iocb->ki_run_list is empty at this point so it should
810 * be safe to unconditionally queue the context into the
811 * work queue.
812 */
813 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 }
815 }
816 return ret;
817}
818
819/*
820 * __aio_run_iocbs:
821 * Process all pending retries queued on the ioctx
822 * run list.
823 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800824 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 */
826static int __aio_run_iocbs(struct kioctx *ctx)
827{
828 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700829 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
Zach Brownd00689a2005-11-13 16:07:34 -0800831 assert_spin_locked(&ctx->ctx_lock);
832
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700833 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 while (!list_empty(&run_list)) {
835 iocb = list_entry(run_list.next, struct kiocb,
836 ki_run_list);
837 list_del(&iocb->ki_run_list);
838 /*
839 * Hold an extra reference while retrying i/o.
840 */
841 iocb->ki_users++; /* grab extra reference */
842 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800843 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 if (!list_empty(&ctx->run_list))
846 return 1;
847 return 0;
848}
849
850static void aio_queue_work(struct kioctx * ctx)
851{
852 unsigned long timeout;
853 /*
854 * if someone is waiting, get the work started right
855 * away, otherwise, use a longer delay
856 */
857 smp_mb();
858 if (waitqueue_active(&ctx->wait))
859 timeout = 1;
860 else
861 timeout = HZ/10;
862 queue_delayed_work(aio_wq, &ctx->wq, timeout);
863}
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865/*
Jeff Moyerd3486f82011-01-12 17:01:08 -0800866 * aio_run_all_iocbs:
867 * Process all pending retries queued on the ioctx
868 * run list, and keep running them until the list
869 * stays empty.
870 * Assumes it is operating within the aio issuer's mm context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 */
872static inline void aio_run_all_iocbs(struct kioctx *ctx)
873{
874 spin_lock_irq(&ctx->ctx_lock);
875 while (__aio_run_iocbs(ctx))
876 ;
877 spin_unlock_irq(&ctx->ctx_lock);
878}
879
880/*
881 * aio_kick_handler:
882 * Work queue handler triggered to process pending
883 * retries on an ioctx. Takes on the aio issuer's
884 * mm context before running the iocbs, so that
885 * copy_xxx_user operates on the issuer's address
886 * space.
887 * Run on aiod's context.
888 */
David Howells65f27f32006-11-22 14:55:48 +0000889static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890{
David Howells65f27f32006-11-22 14:55:48 +0000891 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800893 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 int requeue;
895
896 set_fs(USER_DS);
897 use_mm(ctx->mm);
898 spin_lock_irq(&ctx->ctx_lock);
899 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800900 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800902 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 set_fs(oldfs);
904 /*
Al Viro9fcf03d2012-03-13 22:06:28 -0400905 * we're in a worker thread already; no point using non-zero delay
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 */
907 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000908 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909}
910
911
912/*
913 * Called by kick_iocb to queue the kiocb for retry
914 * and if required activate the aio work queue to process
915 * it
916 */
Zach Brown998765e2005-09-30 11:58:54 -0700917static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918{
919 struct kioctx *ctx = iocb->ki_ctx;
920 unsigned long flags;
921 int run = 0;
922
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700924 /* set this inside the lock so that we can't race with aio_run_iocb()
925 * testing it and putting the iocb on the run list under the lock */
926 if (!kiocbTryKick(iocb))
927 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700929 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931}
932
933/*
934 * kick_iocb:
935 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800936 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 * The retry is usually executed by aio workqueue
938 * threads (See aio_kick_handler).
939 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800940void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941{
942 /* sync iocbs are easy: they can only ever be executing from a
943 * single context. */
944 if (is_sync_kiocb(iocb)) {
945 kiocbSetKicked(iocb);
946 wake_up_process(iocb->ki_obj.tsk);
947 return;
948 }
949
Zach Brown998765e2005-09-30 11:58:54 -0700950 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951}
952EXPORT_SYMBOL(kick_iocb);
953
954/* aio_complete
955 * Called when the io request on the given iocb is complete.
956 * Returns true if this is the last user of the request. The
957 * only other user of the request can be the cancellation code.
958 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800959int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960{
961 struct kioctx *ctx = iocb->ki_ctx;
962 struct aio_ring_info *info;
963 struct aio_ring *ring;
964 struct io_event *event;
965 unsigned long flags;
966 unsigned long tail;
967 int ret;
968
Zach Brown20dcae32005-11-13 16:07:33 -0800969 /*
970 * Special case handling for sync iocbs:
971 * - events go directly into the iocb for fast handling
972 * - the sync task with the iocb in its stack holds the single iocb
973 * ref, no other paths have a way to get another ref
974 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 */
976 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800977 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800979 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800981 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 }
983
984 info = &ctx->ring_info;
985
986 /* add a completion event to the ring buffer.
987 * must be done holding ctx->ctx_lock to prevent
988 * other code from messing with the tail
989 * pointer since we might be called from irq
990 * context.
991 */
992 spin_lock_irqsave(&ctx->ctx_lock, flags);
993
994 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
995 list_del_init(&iocb->ki_run_list);
996
997 /*
998 * cancelled requests don't get events, userland was given one
999 * when the event got cancelled.
1000 */
1001 if (kiocbIsCancelled(iocb))
1002 goto put_rq;
1003
Cong Wange8e3c3d2011-11-25 23:14:27 +08001004 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005
1006 tail = info->tail;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001007 event = aio_ring_event(info, tail);
Ken Chen4bf69b22005-05-01 08:59:15 -07001008 if (++tail >= info->nr)
1009 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010
1011 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
1012 event->data = iocb->ki_user_data;
1013 event->res = res;
1014 event->res2 = res2;
1015
1016 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
1017 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
1018 res, res2);
1019
1020 /* after flagging the request as done, we
1021 * must never even look at it again
1022 */
1023 smp_wmb(); /* make event visible before updating tail */
1024
1025 info->tail = tail;
1026 ring->tail = tail;
1027
Cong Wange8e3c3d2011-11-25 23:14:27 +08001028 put_aio_ring_event(event);
1029 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030
1031 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001032
1033 /*
1034 * Check if the user asked us to deliver the result through an
1035 * eventfd. The eventfd_signal() function is safe to be called
1036 * from IRQ context.
1037 */
Davide Libenzi87c3a862009-03-18 17:04:19 -07001038 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -07001039 eventfd_signal(iocb->ki_eventfd, 1);
1040
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041put_rq:
1042 /* everything turned out well, dispose of the aiocb. */
1043 ret = __aio_put_req(ctx, iocb);
1044
Quentin Barnes6cb2a212008-03-19 17:00:39 -07001045 /*
1046 * We have to order our ring_info tail store above and test
1047 * of the wait list below outside the wait lock. This is
1048 * like in wake_up_bit() where clearing a bit has to be
1049 * ordered with the unlocked test.
1050 */
1051 smp_mb();
1052
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 if (waitqueue_active(&ctx->wait))
1054 wake_up(&ctx->wait);
1055
Ken Chendee11c22007-02-03 01:13:45 -08001056 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 return ret;
1058}
H Hartley Sweeten385773e2009-09-22 16:43:53 -07001059EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060
1061/* aio_read_evt
1062 * Pull an event off of the ioctx's event ring. Returns the number of
1063 * events fetched (0 or 1 ;-)
1064 * FIXME: make this use cmpxchg.
1065 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1066 */
1067static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1068{
1069 struct aio_ring_info *info = &ioctx->ring_info;
1070 struct aio_ring *ring;
1071 unsigned long head;
1072 int ret = 0;
1073
Cong Wange8e3c3d2011-11-25 23:14:27 +08001074 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1076 (unsigned long)ring->head, (unsigned long)ring->tail,
1077 (unsigned long)ring->nr);
1078
1079 if (ring->head == ring->tail)
1080 goto out;
1081
1082 spin_lock(&info->ring_lock);
1083
1084 head = ring->head % info->nr;
1085 if (head != ring->tail) {
Cong Wange8e3c3d2011-11-25 23:14:27 +08001086 struct io_event *evp = aio_ring_event(info, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 *ent = *evp;
1088 head = (head + 1) % info->nr;
1089 smp_mb(); /* finish reading the event before updatng the head */
1090 ring->head = head;
1091 ret = 1;
Cong Wange8e3c3d2011-11-25 23:14:27 +08001092 put_aio_ring_event(evp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 }
1094 spin_unlock(&info->ring_lock);
1095
1096out:
Cong Wange8e3c3d2011-11-25 23:14:27 +08001097 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1099 (unsigned long)ring->head, (unsigned long)ring->tail);
1100 return ret;
1101}
1102
1103struct aio_timeout {
1104 struct timer_list timer;
1105 int timed_out;
1106 struct task_struct *p;
1107};
1108
1109static void timeout_func(unsigned long data)
1110{
1111 struct aio_timeout *to = (struct aio_timeout *)data;
1112
1113 to->timed_out = 1;
1114 wake_up_process(to->p);
1115}
1116
1117static inline void init_timeout(struct aio_timeout *to)
1118{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001119 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 to->timed_out = 0;
1121 to->p = current;
1122}
1123
1124static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1125 const struct timespec *ts)
1126{
1127 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1128 if (time_after(to->timer.expires, jiffies))
1129 add_timer(&to->timer);
1130 else
1131 to->timed_out = 1;
1132}
1133
1134static inline void clear_timeout(struct aio_timeout *to)
1135{
1136 del_singleshot_timer_sync(&to->timer);
1137}
1138
1139static int read_events(struct kioctx *ctx,
1140 long min_nr, long nr,
1141 struct io_event __user *event,
1142 struct timespec __user *timeout)
1143{
1144 long start_jiffies = jiffies;
1145 struct task_struct *tsk = current;
1146 DECLARE_WAITQUEUE(wait, tsk);
1147 int ret;
1148 int i = 0;
1149 struct io_event ent;
1150 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 int retry = 0;
1152
1153 /* needed to zero any padding within an entry (there shouldn't be
1154 * any, but C is fun!
1155 */
1156 memset(&ent, 0, sizeof(ent));
1157retry:
1158 ret = 0;
1159 while (likely(i < nr)) {
1160 ret = aio_read_evt(ctx, &ent);
1161 if (unlikely(ret <= 0))
1162 break;
1163
1164 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1165 ent.data, ent.obj, ent.res, ent.res2);
1166
1167 /* Could we split the check in two? */
1168 ret = -EFAULT;
1169 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1170 dprintk("aio: lost an event due to EFAULT.\n");
1171 break;
1172 }
1173 ret = 0;
1174
1175 /* Good, event copied to userland, update counts. */
1176 event ++;
1177 i ++;
1178 }
1179
1180 if (min_nr <= i)
1181 return i;
1182 if (ret)
1183 return ret;
1184
1185 /* End fast path */
1186
1187 /* racey check, but it gets redone */
1188 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1189 retry = 1;
1190 aio_run_all_iocbs(ctx);
1191 goto retry;
1192 }
1193
1194 init_timeout(&to);
1195 if (timeout) {
1196 struct timespec ts;
1197 ret = -EFAULT;
1198 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1199 goto out;
1200
1201 set_timeout(start_jiffies, &to, &ts);
1202 }
1203
1204 while (likely(i < nr)) {
1205 add_wait_queue_exclusive(&ctx->wait, &wait);
1206 do {
1207 set_task_state(tsk, TASK_INTERRUPTIBLE);
1208 ret = aio_read_evt(ctx, &ent);
1209 if (ret)
1210 break;
1211 if (min_nr <= i)
1212 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001213 if (unlikely(ctx->dead)) {
1214 ret = -EINVAL;
1215 break;
1216 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 if (to.timed_out) /* Only check after read evt */
1218 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001219 /* Try to only show up in io wait if there are ops
1220 * in flight */
1221 if (ctx->reqs_active)
1222 io_schedule();
1223 else
1224 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 if (signal_pending(tsk)) {
1226 ret = -EINTR;
1227 break;
1228 }
1229 /*ret = aio_read_evt(ctx, &ent);*/
1230 } while (1) ;
1231
1232 set_task_state(tsk, TASK_RUNNING);
1233 remove_wait_queue(&ctx->wait, &wait);
1234
1235 if (unlikely(ret <= 0))
1236 break;
1237
1238 ret = -EFAULT;
1239 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1240 dprintk("aio: lost an event due to EFAULT.\n");
1241 break;
1242 }
1243
1244 /* Good, event copied to userland, update counts. */
1245 event ++;
1246 i ++;
1247 }
1248
1249 if (timeout)
1250 clear_timeout(&to);
1251out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001252 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 return i ? i : ret;
1254}
1255
1256/* Take an ioctx and remove it from the list of ioctx's. Protects
1257 * against races with itself via ->dead.
1258 */
1259static void io_destroy(struct kioctx *ioctx)
1260{
1261 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 int was_dead;
1263
1264 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001265 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 was_dead = ioctx->dead;
1267 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001268 hlist_del_rcu(&ioctx->list);
1269 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270
1271 dprintk("aio_release(%p)\n", ioctx);
1272 if (likely(!was_dead))
1273 put_ioctx(ioctx); /* twice for the list */
1274
Al Viro06af1212012-03-20 16:26:24 -04001275 kill_ctx(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001276
1277 /*
1278 * Wake up any waiters. The setting of ctx->dead must be seen
1279 * by other CPUs at this point. Right now, we rely on the
1280 * locking done by the above calls to ensure this consistency.
1281 */
Roland Dreiere91f90b2011-03-22 16:35:10 -07001282 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283}
1284
1285/* sys_io_setup:
1286 * Create an aio_context capable of receiving at least nr_events.
1287 * ctxp must not point to an aio_context that already exists, and
1288 * must be initialized to 0 prior to the call. On successful
1289 * creation of the aio_context, *ctxp is filled in with the resulting
1290 * handle. May fail with -EINVAL if *ctxp is not initialized,
1291 * if the specified nr_events exceeds internal limits. May fail
1292 * with -EAGAIN if the specified nr_events exceeds the user's limit
1293 * of available events. May fail with -ENOMEM if insufficient kernel
1294 * resources are available. May fail with -EFAULT if an invalid
1295 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1296 * implemented.
1297 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001298SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299{
1300 struct kioctx *ioctx = NULL;
1301 unsigned long ctx;
1302 long ret;
1303
1304 ret = get_user(ctx, ctxp);
1305 if (unlikely(ret))
1306 goto out;
1307
1308 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001309 if (unlikely(ctx || nr_events == 0)) {
1310 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1311 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 goto out;
1313 }
1314
1315 ioctx = ioctx_alloc(nr_events);
1316 ret = PTR_ERR(ioctx);
1317 if (!IS_ERR(ioctx)) {
1318 ret = put_user(ioctx->user_id, ctxp);
Al Viroa2e18592012-03-20 16:27:57 -04001319 if (ret)
1320 io_destroy(ioctx);
1321 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 }
1323
1324out:
1325 return ret;
1326}
1327
1328/* sys_io_destroy:
1329 * Destroy the aio_context specified. May cancel any outstanding
1330 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001331 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 * is invalid.
1333 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001334SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335{
1336 struct kioctx *ioctx = lookup_ioctx(ctx);
1337 if (likely(NULL != ioctx)) {
1338 io_destroy(ioctx);
Al Viroa2e18592012-03-20 16:27:57 -04001339 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 return 0;
1341 }
1342 pr_debug("EINVAL: io_destroy: invalid context id\n");
1343 return -EINVAL;
1344}
1345
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001346static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1347{
1348 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1349
1350 BUG_ON(ret <= 0);
1351
1352 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1353 ssize_t this = min((ssize_t)iov->iov_len, ret);
1354 iov->iov_base += this;
1355 iov->iov_len -= this;
1356 iocb->ki_left -= this;
1357 ret -= this;
1358 if (iov->iov_len == 0) {
1359 iocb->ki_cur_seg++;
1360 iov++;
1361 }
1362 }
1363
1364 /* the caller should not have done more io than what fit in
1365 * the remaining iovecs */
1366 BUG_ON(ret > 0 && iocb->ki_left == 0);
1367}
1368
1369static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370{
1371 struct file *file = iocb->ki_filp;
1372 struct address_space *mapping = file->f_mapping;
1373 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001374 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1375 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001377 unsigned short opcode;
1378
1379 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1380 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1381 rw_op = file->f_op->aio_read;
1382 opcode = IOCB_CMD_PREADV;
1383 } else {
1384 rw_op = file->f_op->aio_write;
1385 opcode = IOCB_CMD_PWRITEV;
1386 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387
Rusty Russellc2ec6682008-02-08 04:20:15 -08001388 /* This matches the pread()/pwrite() logic */
1389 if (iocb->ki_pos < 0)
1390 return -EINVAL;
1391
Zach Brown897f15f2005-09-30 11:58:55 -07001392 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001393 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1394 iocb->ki_nr_segs - iocb->ki_cur_seg,
1395 iocb->ki_pos);
1396 if (ret > 0)
1397 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001398
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001399 /* retry all partial writes. retry partial reads as long as its a
1400 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001401 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001402 (opcode == IOCB_CMD_PWRITEV ||
1403 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
1405 /* This means we must have transferred all that we could */
1406 /* No need to retry anymore */
1407 if ((ret == 0) || (iocb->ki_left == 0))
1408 ret = iocb->ki_nbytes - iocb->ki_left;
1409
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001410 /* If we managed to write some out we return that, rather than
1411 * the eventual error. */
1412 if (opcode == IOCB_CMD_PWRITEV
1413 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1414 && iocb->ki_nbytes - iocb->ki_left)
1415 ret = iocb->ki_nbytes - iocb->ki_left;
1416
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 return ret;
1418}
1419
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420static ssize_t aio_fdsync(struct kiocb *iocb)
1421{
1422 struct file *file = iocb->ki_filp;
1423 ssize_t ret = -EINVAL;
1424
1425 if (file->f_op->aio_fsync)
1426 ret = file->f_op->aio_fsync(iocb, 1);
1427 return ret;
1428}
1429
1430static ssize_t aio_fsync(struct kiocb *iocb)
1431{
1432 struct file *file = iocb->ki_filp;
1433 ssize_t ret = -EINVAL;
1434
1435 if (file->f_op->aio_fsync)
1436 ret = file->f_op->aio_fsync(iocb, 0);
1437 return ret;
1438}
1439
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001440static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001441{
1442 ssize_t ret;
1443
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001444#ifdef CONFIG_COMPAT
1445 if (compat)
1446 ret = compat_rw_copy_check_uvector(type,
1447 (struct compat_iovec __user *)kiocb->ki_buf,
1448 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001449 &kiocb->ki_iovec, 1);
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001450 else
1451#endif
1452 ret = rw_copy_check_uvector(type,
1453 (struct iovec __user *)kiocb->ki_buf,
1454 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohfcf63402011-10-31 17:06:39 -07001455 &kiocb->ki_iovec, 1);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001456 if (ret < 0)
1457 goto out;
1458
1459 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1460 kiocb->ki_cur_seg = 0;
1461 /* ki_nbytes/left now reflect bytes instead of segs */
1462 kiocb->ki_nbytes = ret;
1463 kiocb->ki_left = ret;
1464
1465 ret = 0;
1466out:
1467 return ret;
1468}
1469
1470static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1471{
1472 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1473 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1474 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1475 kiocb->ki_nr_segs = 1;
1476 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001477 return 0;
1478}
1479
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480/*
1481 * aio_setup_iocb:
1482 * Performs the initial checks and aio retry method
1483 * setup for the kiocb at the time of io submission.
1484 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001485static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486{
1487 struct file *file = kiocb->ki_filp;
1488 ssize_t ret = 0;
1489
1490 switch (kiocb->ki_opcode) {
1491 case IOCB_CMD_PREAD:
1492 ret = -EBADF;
1493 if (unlikely(!(file->f_mode & FMODE_READ)))
1494 break;
1495 ret = -EFAULT;
1496 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1497 kiocb->ki_left)))
1498 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001499 ret = security_file_permission(file, MAY_READ);
1500 if (unlikely(ret))
1501 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001502 ret = aio_setup_single_vector(kiocb);
1503 if (ret)
1504 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 ret = -EINVAL;
1506 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001507 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 break;
1509 case IOCB_CMD_PWRITE:
1510 ret = -EBADF;
1511 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1512 break;
1513 ret = -EFAULT;
1514 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1515 kiocb->ki_left)))
1516 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001517 ret = security_file_permission(file, MAY_WRITE);
1518 if (unlikely(ret))
1519 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001520 ret = aio_setup_single_vector(kiocb);
1521 if (ret)
1522 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 ret = -EINVAL;
1524 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001525 kiocb->ki_retry = aio_rw_vect_retry;
1526 break;
1527 case IOCB_CMD_PREADV:
1528 ret = -EBADF;
1529 if (unlikely(!(file->f_mode & FMODE_READ)))
1530 break;
1531 ret = security_file_permission(file, MAY_READ);
1532 if (unlikely(ret))
1533 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001534 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001535 if (ret)
1536 break;
1537 ret = -EINVAL;
1538 if (file->f_op->aio_read)
1539 kiocb->ki_retry = aio_rw_vect_retry;
1540 break;
1541 case IOCB_CMD_PWRITEV:
1542 ret = -EBADF;
1543 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1544 break;
1545 ret = security_file_permission(file, MAY_WRITE);
1546 if (unlikely(ret))
1547 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001548 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001549 if (ret)
1550 break;
1551 ret = -EINVAL;
1552 if (file->f_op->aio_write)
1553 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 break;
1555 case IOCB_CMD_FDSYNC:
1556 ret = -EINVAL;
1557 if (file->f_op->aio_fsync)
1558 kiocb->ki_retry = aio_fdsync;
1559 break;
1560 case IOCB_CMD_FSYNC:
1561 ret = -EINVAL;
1562 if (file->f_op->aio_fsync)
1563 kiocb->ki_retry = aio_fsync;
1564 break;
1565 default:
1566 dprintk("EINVAL: io_submit: no operation provided\n");
1567 ret = -EINVAL;
1568 }
1569
1570 if (!kiocb->ki_retry)
1571 return ret;
1572
1573 return 0;
1574}
1575
Adrian Bunkd5470b52008-04-29 00:58:57 -07001576static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer080d6762011-11-02 13:40:10 -07001577 struct iocb *iocb, struct kiocb_batch *batch,
1578 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579{
1580 struct kiocb *req;
1581 struct file *file;
1582 ssize_t ret;
1583
1584 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001585 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 pr_debug("EINVAL: io_submit: reserve field set\n");
1587 return -EINVAL;
1588 }
1589
1590 /* prevent overflows */
1591 if (unlikely(
1592 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1593 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1594 ((ssize_t)iocb->aio_nbytes < 0)
1595 )) {
1596 pr_debug("EINVAL: io_submit: overflow check\n");
1597 return -EINVAL;
1598 }
1599
1600 file = fget(iocb->aio_fildes);
1601 if (unlikely(!file))
1602 return -EBADF;
1603
Jeff Moyer080d6762011-11-02 13:40:10 -07001604 req = aio_get_req(ctx, batch); /* returns with 2 references to req */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 if (unlikely(!req)) {
1606 fput(file);
1607 return -EAGAIN;
1608 }
Yan Zheng87e28312007-10-08 12:16:20 -07001609 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001610 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1611 /*
1612 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1613 * instance of the file* now. The file descriptor must be
1614 * an eventfd() fd, and will be signaled for each completed
1615 * event using the eventfd_signal() function.
1616 */
Davide Libenzi13389012009-06-30 11:41:11 -07001617 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001618 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001619 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001620 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001621 goto out_put_req;
1622 }
1623 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624
Ken Chen212079c2005-05-01 08:59:15 -07001625 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 if (unlikely(ret)) {
1627 dprintk("EFAULT: aio_key\n");
1628 goto out_put_req;
1629 }
1630
1631 req->ki_obj.user = user_iocb;
1632 req->ki_user_data = iocb->aio_data;
1633 req->ki_pos = iocb->aio_offset;
1634
1635 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1636 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1637 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001639 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640
1641 if (ret)
1642 goto out_put_req;
1643
1644 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001645 /*
1646 * We could have raced with io_destroy() and are currently holding a
1647 * reference to ctx which should be destroyed. We cannot submit IO
1648 * since ctx gets freed as soon as io_submit() puts its reference. The
1649 * check here is reliable: io_destroy() sets ctx->dead before waiting
1650 * for outstanding IO and the barrier between these two is realized by
1651 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1652 * increment ctx->reqs_active before checking for ctx->dead and the
1653 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1654 * don't see ctx->dead set here, io_destroy() waits for our IO to
1655 * finish.
1656 */
1657 if (ctx->dead) {
1658 spin_unlock_irq(&ctx->ctx_lock);
1659 ret = -EINVAL;
1660 goto out_put_req;
1661 }
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001662 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001663 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001664 /* drain the run list */
1665 while (__aio_run_iocbs(ctx))
1666 ;
1667 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001669
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 aio_put_req(req); /* drop extra ref to req */
1671 return 0;
1672
1673out_put_req:
1674 aio_put_req(req); /* drop extra ref to req */
1675 aio_put_req(req); /* drop i/o ref to req */
1676 return ret;
1677}
1678
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001679long do_io_submit(aio_context_t ctx_id, long nr,
1680 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681{
1682 struct kioctx *ctx;
1683 long ret = 0;
Jeff Moyer080d6762011-11-02 13:40:10 -07001684 int i = 0;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001685 struct blk_plug plug;
Jeff Moyer080d6762011-11-02 13:40:10 -07001686 struct kiocb_batch batch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687
1688 if (unlikely(nr < 0))
1689 return -EINVAL;
1690
Jeff Moyer75e1c702010-09-10 14:16:00 -07001691 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1692 nr = LONG_MAX/sizeof(*iocbpp);
1693
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1695 return -EFAULT;
1696
1697 ctx = lookup_ioctx(ctx_id);
1698 if (unlikely(!ctx)) {
1699 pr_debug("EINVAL: io_submit: invalid context id\n");
1700 return -EINVAL;
1701 }
1702
Jeff Moyer080d6762011-11-02 13:40:10 -07001703 kiocb_batch_init(&batch, nr);
1704
Shaohua Li9f5b9422010-07-01 07:55:01 +02001705 blk_start_plug(&plug);
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 /*
1708 * AKPM: should this return a partial result if some of the IOs were
1709 * successfully submitted?
1710 */
1711 for (i=0; i<nr; i++) {
1712 struct iocb __user *user_iocb;
1713 struct iocb tmp;
1714
1715 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1716 ret = -EFAULT;
1717 break;
1718 }
1719
1720 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1721 ret = -EFAULT;
1722 break;
1723 }
1724
Jeff Moyer080d6762011-11-02 13:40:10 -07001725 ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 if (ret)
1727 break;
1728 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001729 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
Gleb Natapov69e47472012-01-08 17:07:28 +02001731 kiocb_batch_free(ctx, &batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 put_ioctx(ctx);
1733 return i ? i : ret;
1734}
1735
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001736/* sys_io_submit:
1737 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1738 * the number of iocbs queued. May return -EINVAL if the aio_context
1739 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1740 * *iocbpp[0] is not properly initialized, if the operation specified
1741 * is invalid for the file descriptor in the iocb. May fail with
1742 * -EFAULT if any of the data structures point to invalid data. May
1743 * fail with -EBADF if the file descriptor specified in the first
1744 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1745 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1746 * fail with -ENOSYS if not implemented.
1747 */
1748SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1749 struct iocb __user * __user *, iocbpp)
1750{
1751 return do_io_submit(ctx_id, nr, iocbpp, 0);
1752}
1753
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754/* lookup_kiocb
1755 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001757static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1758 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759{
1760 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001761
1762 assert_spin_locked(&ctx->ctx_lock);
1763
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 /* TODO: use a hash or array, this sucks. */
1765 list_for_each(pos, &ctx->active_reqs) {
1766 struct kiocb *kiocb = list_kiocb(pos);
1767 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1768 return kiocb;
1769 }
1770 return NULL;
1771}
1772
1773/* sys_io_cancel:
1774 * Attempts to cancel an iocb previously passed to io_submit. If
1775 * the operation is successfully cancelled, the resulting event is
1776 * copied into the memory pointed to by result without being placed
1777 * into the completion queue and 0 is returned. May fail with
1778 * -EFAULT if any of the data structures pointed to are invalid.
1779 * May fail with -EINVAL if aio_context specified by ctx_id is
1780 * invalid. May fail with -EAGAIN if the iocb specified was not
1781 * cancelled. Will fail with -ENOSYS if not implemented.
1782 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001783SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1784 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785{
1786 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1787 struct kioctx *ctx;
1788 struct kiocb *kiocb;
1789 u32 key;
1790 int ret;
1791
1792 ret = get_user(key, &iocb->aio_key);
1793 if (unlikely(ret))
1794 return -EFAULT;
1795
1796 ctx = lookup_ioctx(ctx_id);
1797 if (unlikely(!ctx))
1798 return -EINVAL;
1799
1800 spin_lock_irq(&ctx->ctx_lock);
1801 ret = -EAGAIN;
1802 kiocb = lookup_kiocb(ctx, iocb, key);
1803 if (kiocb && kiocb->ki_cancel) {
1804 cancel = kiocb->ki_cancel;
1805 kiocb->ki_users ++;
1806 kiocbSetCancelled(kiocb);
1807 } else
1808 cancel = NULL;
1809 spin_unlock_irq(&ctx->ctx_lock);
1810
1811 if (NULL != cancel) {
1812 struct io_event tmp;
1813 pr_debug("calling cancel\n");
1814 memset(&tmp, 0, sizeof(tmp));
1815 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1816 tmp.data = kiocb->ki_user_data;
1817 ret = cancel(kiocb, &tmp);
1818 if (!ret) {
1819 /* Cancellation succeeded -- copy the result
1820 * into the user's buffer.
1821 */
1822 if (copy_to_user(result, &tmp, sizeof(tmp)))
1823 ret = -EFAULT;
1824 }
1825 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001826 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827
1828 put_ioctx(ctx);
1829
1830 return ret;
1831}
1832
1833/* io_getevents:
1834 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001835 * the completion queue for the aio_context specified by ctx_id. If
1836 * it succeeds, the number of read events is returned. May fail with
1837 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1838 * out of range, if timeout is out of range. May fail with -EFAULT
1839 * if any of the memory specified is invalid. May return 0 or
1840 * < min_nr if the timeout specified by timeout has elapsed
1841 * before sufficient events are available, where timeout == NULL
1842 * specifies an infinite timeout. Note that the timeout pointed to by
1843 * timeout is relative and will be updated if not NULL and the
1844 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001846SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1847 long, min_nr,
1848 long, nr,
1849 struct io_event __user *, events,
1850 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851{
1852 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1853 long ret = -EINVAL;
1854
1855 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001856 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 ret = read_events(ioctx, min_nr, nr, events, timeout);
1858 put_ioctx(ioctx);
1859 }
1860
Roland McGrath598af052008-04-10 15:38:45 -07001861 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862 return ret;
1863}