blob: 8b43d6bf8c50715db535017076150ca6d1aa5a6b [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 Moyer9d85cba72010-05-26 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070057/* aio_setup
58 * Creates the slab caches used by the aio routines, panic on
59 * failure as this is done early during the boot sequence.
60 */
61static int __init aio_setup(void)
62{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070063 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
64 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
67
68 return 0;
69}
H Hartley Sweeten385773e2009-09-22 16:43:53 -070070__initcall(aio_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
72static void aio_free_ring(struct kioctx *ctx)
73{
74 struct aio_ring_info *info = &ctx->ring_info;
75 long i;
76
77 for (i=0; i<info->nr_pages; i++)
78 put_page(info->ring_pages[i]);
79
Al Viro936af152012-04-20 21:49:41 -040080 if (info->mmap_size) {
Al Virobfce2812012-04-20 21:57:04 -040081 vm_munmap(info->mmap_base, info->mmap_size);
Al Viro936af152012-04-20 21:49:41 -040082 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
84 if (info->ring_pages && info->ring_pages != info->internal_pages)
85 kfree(info->ring_pages);
86 info->ring_pages = NULL;
87 info->nr = 0;
88}
89
90static int aio_setup_ring(struct kioctx *ctx)
91{
92 struct aio_ring *ring;
93 struct aio_ring_info *info = &ctx->ring_info;
94 unsigned nr_events = ctx->max_reqs;
Zach Brown41003a72013-05-07 16:18:25 -070095 struct mm_struct *mm = current->mm;
Michel Lespinasse41badc12013-02-22 16:32:47 -080096 unsigned long size, populate;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 int nr_pages;
98
99 /* Compensate for the ring buffer's head/tail overlap entry */
100 nr_events += 2; /* 1 is required, 2 for good luck */
101
102 size = sizeof(struct aio_ring);
103 size += sizeof(struct io_event) * nr_events;
104 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
105
106 if (nr_pages < 0)
107 return -EINVAL;
108
109 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
110
111 info->nr = 0;
112 info->ring_pages = info->internal_pages;
113 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800114 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 if (!info->ring_pages)
116 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 }
118
119 info->mmap_size = nr_pages * PAGE_SIZE;
120 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
Zach Brown41003a72013-05-07 16:18:25 -0700121 down_write(&mm->mmap_sem);
Al Viroe3fc6292012-05-30 20:08:42 -0400122 info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size,
123 PROT_READ|PROT_WRITE,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800124 MAP_ANONYMOUS|MAP_PRIVATE, 0,
125 &populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 if (IS_ERR((void *)info->mmap_base)) {
Zach Brown41003a72013-05-07 16:18:25 -0700127 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 info->mmap_size = 0;
129 aio_free_ring(ctx);
130 return -EAGAIN;
131 }
132
133 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
Zach Brown41003a72013-05-07 16:18:25 -0700134 info->nr_pages = get_user_pages(current, mm, info->mmap_base, nr_pages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 1, 0, info->ring_pages, NULL);
Zach Brown41003a72013-05-07 16:18:25 -0700136 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138 if (unlikely(info->nr_pages != nr_pages)) {
139 aio_free_ring(ctx);
140 return -EAGAIN;
141 }
Michel Lespinassebebeb3d2013-02-22 16:32:37 -0800142 if (populate)
Michel Lespinasse41badc12013-02-22 16:32:47 -0800143 mm_populate(info->mmap_base, populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 ctx->user_id = info->mmap_base;
146
147 info->nr = nr_events; /* trusted copy */
148
Cong Wange8e3c3d2011-11-25 23:14:27 +0800149 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 ring->nr = nr_events; /* user copy */
151 ring->id = ctx->user_id;
152 ring->head = ring->tail = 0;
153 ring->magic = AIO_RING_MAGIC;
154 ring->compat_features = AIO_RING_COMPAT_FEATURES;
155 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
156 ring->header_length = sizeof(struct aio_ring);
Cong Wange8e3c3d2011-11-25 23:14:27 +0800157 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
159 return 0;
160}
161
162
163/* aio_ring_event: returns a pointer to the event at the given index from
Cong Wange8e3c3d2011-11-25 23:14:27 +0800164 * kmap_atomic(). Release the pointer with put_aio_ring_event();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 */
166#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
167#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
168#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
169
Cong Wange8e3c3d2011-11-25 23:14:27 +0800170#define aio_ring_event(info, nr) ({ \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
172 struct io_event *__event; \
173 __event = kmap_atomic( \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800174 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 __event += pos % AIO_EVENTS_PER_PAGE; \
176 __event; \
177})
178
Cong Wange8e3c3d2011-11-25 23:14:27 +0800179#define put_aio_ring_event(event) do { \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 struct io_event *__event = (event); \
181 (void)__event; \
Cong Wange8e3c3d2011-11-25 23:14:27 +0800182 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183} while(0)
184
Jens Axboeabf137d2008-12-09 08:11:22 +0100185static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700186{
Jens Axboeabf137d2008-12-09 08:11:22 +0100187 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700188 kmem_cache_free(kioctx_cachep, ctx);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700189}
190
Jens Axboeabf137d2008-12-09 08:11:22 +0100191/* __put_ioctx
192 * Called when the last user of an aio context has gone away,
193 * and the struct needs to be freed.
194 */
195static void __put_ioctx(struct kioctx *ctx)
196{
Al Viro2dd542b72012-03-10 23:10:35 -0500197 unsigned nr_events = ctx->max_reqs;
Jens Axboeabf137d2008-12-09 08:11:22 +0100198 BUG_ON(ctx->reqs_active);
199
Jens Axboeabf137d2008-12-09 08:11:22 +0100200 aio_free_ring(ctx);
Al Viro2dd542b72012-03-10 23:10:35 -0500201 if (nr_events) {
202 spin_lock(&aio_nr_lock);
203 BUG_ON(aio_nr - nr_events > aio_nr);
204 aio_nr -= nr_events;
205 spin_unlock(&aio_nr_lock);
206 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100207 pr_debug("__put_ioctx: freeing %p\n", ctx);
208 call_rcu(&ctx->rcu_head, ctx_rcu_free);
209}
210
Nick Piggin3bd9a5d72011-02-25 14:44:26 -0800211static inline int try_get_ioctx(struct kioctx *kioctx)
212{
213 return atomic_inc_not_zero(&kioctx->users);
214}
215
216static inline void put_ioctx(struct kioctx *kioctx)
217{
218 BUG_ON(atomic_read(&kioctx->users) <= 0);
219 if (unlikely(atomic_dec_and_test(&kioctx->users)))
220 __put_ioctx(kioctx);
221}
Adrian Bunkd5470b52008-04-29 00:58:57 -0700222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223/* ioctx_alloc
224 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
225 */
226static struct kioctx *ioctx_alloc(unsigned nr_events)
227{
Zach Brown41003a72013-05-07 16:18:25 -0700228 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 struct kioctx *ctx;
Al Viroe23754f2012-03-06 14:33:22 -0500230 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
232 /* Prevent overflows */
233 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
234 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
235 pr_debug("ENOMEM: nr_events too high\n");
236 return ERR_PTR(-EINVAL);
237 }
238
Al Viro2dd542b72012-03-10 23:10:35 -0500239 if (!nr_events || (unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 return ERR_PTR(-EAGAIN);
241
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800242 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 if (!ctx)
244 return ERR_PTR(-ENOMEM);
245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 ctx->max_reqs = nr_events;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
Al Viro86b62a22012-03-07 05:16:35 +0000248 atomic_set(&ctx->users, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 spin_lock_init(&ctx->ctx_lock);
250 spin_lock_init(&ctx->ring_info.ring_lock);
251 init_waitqueue_head(&ctx->wait);
252
253 INIT_LIST_HEAD(&ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 if (aio_setup_ring(ctx) < 0)
256 goto out_freectx;
257
258 /* limit the number of system wide aios */
Al Viro9fa1cb32012-03-10 23:14:05 -0500259 spin_lock(&aio_nr_lock);
Al Viro2dd542b72012-03-10 23:10:35 -0500260 if (aio_nr + nr_events > aio_max_nr ||
261 aio_nr + nr_events < aio_nr) {
Al Viro9fa1cb32012-03-10 23:14:05 -0500262 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 goto out_cleanup;
Al Viro2dd542b72012-03-10 23:10:35 -0500264 }
265 aio_nr += ctx->max_reqs;
Al Viro9fa1cb32012-03-10 23:14:05 -0500266 spin_unlock(&aio_nr_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Jeff Moyer39fa0032008-04-29 01:03:48 -0700268 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100269 spin_lock(&mm->ioctx_lock);
270 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
271 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
273 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
Zach Brown41003a72013-05-07 16:18:25 -0700274 ctx, ctx->user_id, mm, ctx->ring_info.nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 return ctx;
276
277out_cleanup:
Al Viroe23754f2012-03-06 14:33:22 -0500278 err = -EAGAIN;
279 aio_free_ring(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280out_freectx:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 kmem_cache_free(kioctx_cachep, ctx);
Al Viroe23754f2012-03-06 14:33:22 -0500282 dprintk("aio: error allocating ioctx %d\n", err);
283 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284}
285
Al Viro06af1212012-03-20 16:26:24 -0400286/* kill_ctx
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 * Cancels all outstanding aio requests on an aio context. Used
288 * when the processes owning a context have all exited to encourage
289 * the rapid destruction of the kioctx.
290 */
Al Viro06af1212012-03-20 16:26:24 -0400291static void kill_ctx(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292{
293 int (*cancel)(struct kiocb *, struct io_event *);
Al Viro06af1212012-03-20 16:26:24 -0400294 struct task_struct *tsk = current;
295 DECLARE_WAITQUEUE(wait, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 struct io_event res;
Al Viro06af1212012-03-20 16:26:24 -0400297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 spin_lock_irq(&ctx->ctx_lock);
299 ctx->dead = 1;
300 while (!list_empty(&ctx->active_reqs)) {
301 struct list_head *pos = ctx->active_reqs.next;
302 struct kiocb *iocb = list_kiocb(pos);
303 list_del_init(&iocb->ki_list);
304 cancel = iocb->ki_cancel;
305 kiocbSetCancelled(iocb);
306 if (cancel) {
307 iocb->ki_users++;
308 spin_unlock_irq(&ctx->ctx_lock);
309 cancel(iocb, &res);
310 spin_lock_irq(&ctx->ctx_lock);
311 }
312 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800315 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
317 add_wait_queue(&ctx->wait, &wait);
318 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
319 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800320 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700321 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800323 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 }
325 __set_task_state(tsk, TASK_RUNNING);
326 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800327
328out:
329 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330}
331
332/* wait_on_sync_kiocb:
333 * Waits on the given sync kiocb to complete.
334 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800335ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336{
337 while (iocb->ki_users) {
338 set_current_state(TASK_UNINTERRUPTIBLE);
339 if (!iocb->ki_users)
340 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700341 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 }
343 __set_current_state(TASK_RUNNING);
344 return iocb->ki_user_data;
345}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700346EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
348/* exit_aio: called when the last user of mm goes away. At this point,
349 * there is no way for any new requests to be submited or any of the
350 * io_* syscalls to be called on the context. However, there may be
351 * outstanding requests which hold references to the context; as they
352 * go away, they will call put_ioctx and release any pinned memory
353 * associated with the request (held via struct page * references).
354 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800355void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356{
Jens Axboeabf137d2008-12-09 08:11:22 +0100357 struct kioctx *ctx;
358
359 while (!hlist_empty(&mm->ioctx_list)) {
360 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
361 hlist_del_rcu(&ctx->list);
362
Al Viro06af1212012-03-20 16:26:24 -0400363 kill_ctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
365 if (1 != atomic_read(&ctx->users))
366 printk(KERN_DEBUG
367 "exit_aio:ioctx still alive: %d %d %d\n",
368 atomic_read(&ctx->users), ctx->dead,
369 ctx->reqs_active);
Al Viro936af152012-04-20 21:49:41 -0400370 /*
371 * We don't need to bother with munmap() here -
372 * exit_mmap(mm) is coming and it'll unmap everything.
373 * Since aio_free_ring() uses non-zero ->mmap_size
374 * as indicator that it needs to unmap the area,
375 * just set it to 0; aio_free_ring() is the only
376 * place that uses ->mmap_size, so it's safe.
Al Viro936af152012-04-20 21:49:41 -0400377 */
378 ctx->ring_info.mmap_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 }
381}
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383/* aio_get_req
384 * Allocate a slot for an aio request. Increments the users count
385 * of the kioctx so that the kioctx stays around until all requests are
386 * complete. Returns NULL if no requests are free.
387 *
388 * Returns with kiocb->users set to 2. The io submit code path holds
389 * an extra reference while submitting the i/o.
390 * This prevents races between the aio code path referencing the
391 * req (after submitting it) and aio_complete() freeing the req.
392 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800393static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394{
395 struct kiocb *req = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396
397 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
398 if (unlikely(!req))
399 return NULL;
400
Zach Brown4faa5282005-10-17 16:43:33 -0700401 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 req->ki_users = 2;
403 req->ki_key = 0;
404 req->ki_ctx = ctx;
405 req->ki_cancel = NULL;
406 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 req->ki_dtor = NULL;
408 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700409 req->ki_iovec = NULL;
Davide Libenzi87c3a862009-03-18 17:04:19 -0700410 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 return req;
413}
414
Jeff Moyer080d6762011-11-02 13:40:10 -0700415/*
416 * struct kiocb's are allocated in batches to reduce the number of
417 * times the ctx lock is acquired and released.
418 */
419#define KIOCB_BATCH_SIZE 32L
420struct kiocb_batch {
421 struct list_head head;
422 long count; /* number of requests left to allocate */
423};
424
425static void kiocb_batch_init(struct kiocb_batch *batch, long total)
426{
427 INIT_LIST_HEAD(&batch->head);
428 batch->count = total;
429}
430
Gleb Natapov69e47472012-01-08 17:07:28 +0200431static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
Jeff Moyer080d6762011-11-02 13:40:10 -0700432{
433 struct kiocb *req, *n;
434
Gleb Natapov69e47472012-01-08 17:07:28 +0200435 if (list_empty(&batch->head))
436 return;
437
438 spin_lock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700439 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
440 list_del(&req->ki_batch);
Gleb Natapov69e47472012-01-08 17:07:28 +0200441 list_del(&req->ki_list);
Jeff Moyer080d6762011-11-02 13:40:10 -0700442 kmem_cache_free(kiocb_cachep, req);
Gleb Natapov69e47472012-01-08 17:07:28 +0200443 ctx->reqs_active--;
Jeff Moyer080d6762011-11-02 13:40:10 -0700444 }
Jeff Moyer880641b2012-03-05 14:59:12 -0800445 if (unlikely(!ctx->reqs_active && ctx->dead))
446 wake_up_all(&ctx->wait);
Gleb Natapov69e47472012-01-08 17:07:28 +0200447 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer080d6762011-11-02 13:40:10 -0700448}
449
450/*
451 * Allocate a batch of kiocbs. This avoids taking and dropping the
452 * context lock a lot during setup.
453 */
454static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
455{
456 unsigned short allocated, to_alloc;
457 long avail;
Jeff Moyer080d6762011-11-02 13:40:10 -0700458 struct kiocb *req, *n;
459 struct aio_ring *ring;
460
461 to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
462 for (allocated = 0; allocated < to_alloc; allocated++) {
463 req = __aio_get_req(ctx);
464 if (!req)
465 /* allocation failed, go with what we've got */
466 break;
467 list_add(&req->ki_batch, &batch->head);
468 }
469
470 if (allocated == 0)
471 goto out;
472
Jeff Moyer080d6762011-11-02 13:40:10 -0700473 spin_lock_irq(&ctx->ctx_lock);
474 ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
475
476 avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active;
477 BUG_ON(avail < 0);
Jeff Moyer080d6762011-11-02 13:40:10 -0700478 if (avail < allocated) {
479 /* Trim back the number of requests. */
480 list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
481 list_del(&req->ki_batch);
482 kmem_cache_free(kiocb_cachep, req);
483 if (--allocated <= avail)
484 break;
485 }
486 }
487
488 batch->count -= allocated;
489 list_for_each_entry(req, &batch->head, ki_batch) {
490 list_add(&req->ki_list, &ctx->active_reqs);
491 ctx->reqs_active++;
492 }
493
494 kunmap_atomic(ring);
495 spin_unlock_irq(&ctx->ctx_lock);
496
497out:
498 return allocated;
499}
500
501static inline struct kiocb *aio_get_req(struct kioctx *ctx,
502 struct kiocb_batch *batch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503{
504 struct kiocb *req;
Jeff Moyer080d6762011-11-02 13:40:10 -0700505
506 if (list_empty(&batch->head))
507 if (kiocb_batch_refill(ctx, batch) == 0)
508 return NULL;
509 req = list_first_entry(&batch->head, struct kiocb, ki_batch);
510 list_del(&req->ki_batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 return req;
512}
513
514static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
515{
Zach Brownd00689a2005-11-13 16:07:34 -0800516 assert_spin_locked(&ctx->ctx_lock);
517
Davide Libenzi13389012009-06-30 11:41:11 -0700518 if (req->ki_eventfd != NULL)
519 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 if (req->ki_dtor)
521 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700522 if (req->ki_iovec != &req->ki_inline_vec)
523 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 kmem_cache_free(kiocb_cachep, req);
525 ctx->reqs_active--;
526
527 if (unlikely(!ctx->reqs_active && ctx->dead))
Roland Dreiere91f90b2011-03-22 16:35:10 -0700528 wake_up_all(&ctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529}
530
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531/* __aio_put_req
532 * Returns true if this put was the last user of the request.
533 */
Kent Overstreet2d684492013-05-07 16:18:29 -0700534static void __aio_put_req(struct kioctx *ctx, struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
Al Viro516e0cc2008-07-26 00:39:17 -0400536 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
537 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538
Zach Brownd00689a2005-11-13 16:07:34 -0800539 assert_spin_locked(&ctx->ctx_lock);
540
Davide Libenzi87c3a862009-03-18 17:04:19 -0700541 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100542 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 if (likely(req->ki_users))
Kent Overstreet2d684492013-05-07 16:18:29 -0700544 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 list_del(&req->ki_list); /* remove from active_reqs */
546 req->ki_cancel = NULL;
547 req->ki_retry = NULL;
548
Al Viro3ffa3c02012-06-24 10:00:10 +0400549 fput(req->ki_filp);
550 req->ki_filp = NULL;
551 really_put_req(ctx, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552}
553
554/* aio_put_req
555 * Returns true if this put was the last user of the kiocb,
556 * false if the request is still in use.
557 */
Kent Overstreet2d684492013-05-07 16:18:29 -0700558void aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559{
560 struct kioctx *ctx = req->ki_ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 spin_lock_irq(&ctx->ctx_lock);
Kent Overstreet2d684492013-05-07 16:18:29 -0700562 __aio_put_req(ctx, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700565EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
Adrian Bunkd5470b52008-04-29 00:58:57 -0700567static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568{
Jens Axboeabf137d2008-12-09 08:11:22 +0100569 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700570 struct kioctx *ctx, *ret = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571
Jens Axboeabf137d2008-12-09 08:11:22 +0100572 rcu_read_lock();
573
Sasha Levinb67bfe02013-02-27 17:06:00 -0800574 hlist_for_each_entry_rcu(ctx, &mm->ioctx_list, list) {
Nick Piggin3bd9a5d72011-02-25 14:44:26 -0800575 /*
576 * RCU protects us against accessing freed memory but
577 * we have to be careful not to get a reference when the
578 * reference count already dropped to 0 (ctx->dead test
579 * is unreliable because of races).
580 */
581 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
Jeff Moyer65c24492009-03-18 17:04:21 -0700582 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 break;
584 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100585 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
Jens Axboeabf137d2008-12-09 08:11:22 +0100587 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700588 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589}
590
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591/* aio_complete
592 * Called when the io request on the given iocb is complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 */
Kent Overstreet2d684492013-05-07 16:18:29 -0700594void aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
596 struct kioctx *ctx = iocb->ki_ctx;
597 struct aio_ring_info *info;
598 struct aio_ring *ring;
599 struct io_event *event;
600 unsigned long flags;
601 unsigned long tail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602
Zach Brown20dcae32005-11-13 16:07:33 -0800603 /*
604 * Special case handling for sync iocbs:
605 * - events go directly into the iocb for fast handling
606 * - the sync task with the iocb in its stack holds the single iocb
607 * ref, no other paths have a way to get another ref
608 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 */
610 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800611 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800613 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 wake_up_process(iocb->ki_obj.tsk);
Kent Overstreet2d684492013-05-07 16:18:29 -0700615 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 }
617
618 info = &ctx->ring_info;
619
620 /* add a completion event to the ring buffer.
621 * must be done holding ctx->ctx_lock to prevent
622 * other code from messing with the tail
623 * pointer since we might be called from irq
624 * context.
625 */
626 spin_lock_irqsave(&ctx->ctx_lock, flags);
627
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 /*
629 * cancelled requests don't get events, userland was given one
630 * when the event got cancelled.
631 */
632 if (kiocbIsCancelled(iocb))
633 goto put_rq;
634
Cong Wange8e3c3d2011-11-25 23:14:27 +0800635 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
637 tail = info->tail;
Cong Wange8e3c3d2011-11-25 23:14:27 +0800638 event = aio_ring_event(info, tail);
Ken Chen4bf69b22005-05-01 08:59:15 -0700639 if (++tail >= info->nr)
640 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641
642 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
643 event->data = iocb->ki_user_data;
644 event->res = res;
645 event->res2 = res2;
646
647 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
648 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
649 res, res2);
650
651 /* after flagging the request as done, we
652 * must never even look at it again
653 */
654 smp_wmb(); /* make event visible before updating tail */
655
656 info->tail = tail;
657 ring->tail = tail;
658
Cong Wange8e3c3d2011-11-25 23:14:27 +0800659 put_aio_ring_event(event);
660 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
662 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700663
664 /*
665 * Check if the user asked us to deliver the result through an
666 * eventfd. The eventfd_signal() function is safe to be called
667 * from IRQ context.
668 */
Davide Libenzi87c3a862009-03-18 17:04:19 -0700669 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700670 eventfd_signal(iocb->ki_eventfd, 1);
671
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672put_rq:
673 /* everything turned out well, dispose of the aiocb. */
Kent Overstreet2d684492013-05-07 16:18:29 -0700674 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
Quentin Barnes6cb2a212008-03-19 17:00:39 -0700676 /*
677 * We have to order our ring_info tail store above and test
678 * of the wait list below outside the wait lock. This is
679 * like in wake_up_bit() where clearing a bit has to be
680 * ordered with the unlocked test.
681 */
682 smp_mb();
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 if (waitqueue_active(&ctx->wait))
685 wake_up(&ctx->wait);
686
Ken Chendee11c22007-02-03 01:13:45 -0800687 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700689EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690
691/* aio_read_evt
692 * Pull an event off of the ioctx's event ring. Returns the number of
693 * events fetched (0 or 1 ;-)
694 * FIXME: make this use cmpxchg.
695 * TODO: make the ringbuffer user mmap()able (requires FIXME).
696 */
697static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
698{
699 struct aio_ring_info *info = &ioctx->ring_info;
700 struct aio_ring *ring;
701 unsigned long head;
702 int ret = 0;
703
Cong Wange8e3c3d2011-11-25 23:14:27 +0800704 ring = kmap_atomic(info->ring_pages[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
706 (unsigned long)ring->head, (unsigned long)ring->tail,
707 (unsigned long)ring->nr);
708
709 if (ring->head == ring->tail)
710 goto out;
711
712 spin_lock(&info->ring_lock);
713
714 head = ring->head % info->nr;
715 if (head != ring->tail) {
Cong Wange8e3c3d2011-11-25 23:14:27 +0800716 struct io_event *evp = aio_ring_event(info, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 *ent = *evp;
718 head = (head + 1) % info->nr;
719 smp_mb(); /* finish reading the event before updatng the head */
720 ring->head = head;
721 ret = 1;
Cong Wange8e3c3d2011-11-25 23:14:27 +0800722 put_aio_ring_event(evp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 }
724 spin_unlock(&info->ring_lock);
725
726out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
728 (unsigned long)ring->head, (unsigned long)ring->tail);
Zhao Hongjiang91d80a82013-04-26 11:03:53 +0800729 kunmap_atomic(ring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 return ret;
731}
732
733struct aio_timeout {
734 struct timer_list timer;
735 int timed_out;
736 struct task_struct *p;
737};
738
739static void timeout_func(unsigned long data)
740{
741 struct aio_timeout *to = (struct aio_timeout *)data;
742
743 to->timed_out = 1;
744 wake_up_process(to->p);
745}
746
747static inline void init_timeout(struct aio_timeout *to)
748{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700749 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 to->timed_out = 0;
751 to->p = current;
752}
753
754static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
755 const struct timespec *ts)
756{
757 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
758 if (time_after(to->timer.expires, jiffies))
759 add_timer(&to->timer);
760 else
761 to->timed_out = 1;
762}
763
764static inline void clear_timeout(struct aio_timeout *to)
765{
766 del_singleshot_timer_sync(&to->timer);
767}
768
769static int read_events(struct kioctx *ctx,
770 long min_nr, long nr,
771 struct io_event __user *event,
772 struct timespec __user *timeout)
773{
774 long start_jiffies = jiffies;
775 struct task_struct *tsk = current;
776 DECLARE_WAITQUEUE(wait, tsk);
777 int ret;
778 int i = 0;
779 struct io_event ent;
780 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
782 /* needed to zero any padding within an entry (there shouldn't be
783 * any, but C is fun!
784 */
785 memset(&ent, 0, sizeof(ent));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 ret = 0;
787 while (likely(i < nr)) {
788 ret = aio_read_evt(ctx, &ent);
789 if (unlikely(ret <= 0))
790 break;
791
792 dprintk("read event: %Lx %Lx %Lx %Lx\n",
793 ent.data, ent.obj, ent.res, ent.res2);
794
795 /* Could we split the check in two? */
796 ret = -EFAULT;
797 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
798 dprintk("aio: lost an event due to EFAULT.\n");
799 break;
800 }
801 ret = 0;
802
803 /* Good, event copied to userland, update counts. */
804 event ++;
805 i ++;
806 }
807
808 if (min_nr <= i)
809 return i;
810 if (ret)
811 return ret;
812
813 /* End fast path */
814
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 init_timeout(&to);
816 if (timeout) {
817 struct timespec ts;
818 ret = -EFAULT;
819 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
820 goto out;
821
822 set_timeout(start_jiffies, &to, &ts);
823 }
824
825 while (likely(i < nr)) {
826 add_wait_queue_exclusive(&ctx->wait, &wait);
827 do {
828 set_task_state(tsk, TASK_INTERRUPTIBLE);
829 ret = aio_read_evt(ctx, &ent);
830 if (ret)
831 break;
832 if (min_nr <= i)
833 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -0700834 if (unlikely(ctx->dead)) {
835 ret = -EINVAL;
836 break;
837 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 if (to.timed_out) /* Only check after read evt */
839 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -0800840 /* Try to only show up in io wait if there are ops
841 * in flight */
842 if (ctx->reqs_active)
843 io_schedule();
844 else
845 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 if (signal_pending(tsk)) {
847 ret = -EINTR;
848 break;
849 }
850 /*ret = aio_read_evt(ctx, &ent);*/
851 } while (1) ;
852
853 set_task_state(tsk, TASK_RUNNING);
854 remove_wait_queue(&ctx->wait, &wait);
855
856 if (unlikely(ret <= 0))
857 break;
858
859 ret = -EFAULT;
860 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
861 dprintk("aio: lost an event due to EFAULT.\n");
862 break;
863 }
864
865 /* Good, event copied to userland, update counts. */
866 event ++;
867 i ++;
868 }
869
870 if (timeout)
871 clear_timeout(&to);
872out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700873 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 return i ? i : ret;
875}
876
877/* Take an ioctx and remove it from the list of ioctx's. Protects
878 * against races with itself via ->dead.
879 */
880static void io_destroy(struct kioctx *ioctx)
881{
882 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 int was_dead;
884
885 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +0100886 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 was_dead = ioctx->dead;
888 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +0100889 hlist_del_rcu(&ioctx->list);
890 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
892 dprintk("aio_release(%p)\n", ioctx);
893 if (likely(!was_dead))
894 put_ioctx(ioctx); /* twice for the list */
895
Al Viro06af1212012-03-20 16:26:24 -0400896 kill_ctx(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -0700897
898 /*
899 * Wake up any waiters. The setting of ctx->dead must be seen
900 * by other CPUs at this point. Right now, we rely on the
901 * locking done by the above calls to ensure this consistency.
902 */
Roland Dreiere91f90b2011-03-22 16:35:10 -0700903 wake_up_all(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904}
905
906/* sys_io_setup:
907 * Create an aio_context capable of receiving at least nr_events.
908 * ctxp must not point to an aio_context that already exists, and
909 * must be initialized to 0 prior to the call. On successful
910 * creation of the aio_context, *ctxp is filled in with the resulting
911 * handle. May fail with -EINVAL if *ctxp is not initialized,
912 * if the specified nr_events exceeds internal limits. May fail
913 * with -EAGAIN if the specified nr_events exceeds the user's limit
914 * of available events. May fail with -ENOMEM if insufficient kernel
915 * resources are available. May fail with -EFAULT if an invalid
916 * pointer is passed for ctxp. Will fail with -ENOSYS if not
917 * implemented.
918 */
Heiko Carstens002c8972009-01-14 14:14:18 +0100919SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920{
921 struct kioctx *ioctx = NULL;
922 unsigned long ctx;
923 long ret;
924
925 ret = get_user(ctx, ctxp);
926 if (unlikely(ret))
927 goto out;
928
929 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -0800930 if (unlikely(ctx || nr_events == 0)) {
931 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
932 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 goto out;
934 }
935
936 ioctx = ioctx_alloc(nr_events);
937 ret = PTR_ERR(ioctx);
938 if (!IS_ERR(ioctx)) {
939 ret = put_user(ioctx->user_id, ctxp);
Al Viroa2e18592012-03-20 16:27:57 -0400940 if (ret)
941 io_destroy(ioctx);
942 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 }
944
945out:
946 return ret;
947}
948
949/* sys_io_destroy:
950 * Destroy the aio_context specified. May cancel any outstanding
951 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -0700952 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 * is invalid.
954 */
Heiko Carstens002c8972009-01-14 14:14:18 +0100955SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956{
957 struct kioctx *ioctx = lookup_ioctx(ctx);
958 if (likely(NULL != ioctx)) {
959 io_destroy(ioctx);
Al Viroa2e18592012-03-20 16:27:57 -0400960 put_ioctx(ioctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 return 0;
962 }
963 pr_debug("EINVAL: io_destroy: invalid context id\n");
964 return -EINVAL;
965}
966
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700967static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
968{
969 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
970
971 BUG_ON(ret <= 0);
972
973 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
974 ssize_t this = min((ssize_t)iov->iov_len, ret);
975 iov->iov_base += this;
976 iov->iov_len -= this;
977 iocb->ki_left -= this;
978 ret -= this;
979 if (iov->iov_len == 0) {
980 iocb->ki_cur_seg++;
981 iov++;
982 }
983 }
984
985 /* the caller should not have done more io than what fit in
986 * the remaining iovecs */
987 BUG_ON(ret > 0 && iocb->ki_left == 0);
988}
989
990static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991{
992 struct file *file = iocb->ki_filp;
993 struct address_space *mapping = file->f_mapping;
994 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700995 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
996 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700998 unsigned short opcode;
999
1000 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1001 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1002 rw_op = file->f_op->aio_read;
1003 opcode = IOCB_CMD_PREADV;
1004 } else {
1005 rw_op = file->f_op->aio_write;
1006 opcode = IOCB_CMD_PWRITEV;
1007 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008
Rusty Russellc2ec6682008-02-08 04:20:15 -08001009 /* This matches the pread()/pwrite() logic */
1010 if (iocb->ki_pos < 0)
1011 return -EINVAL;
1012
Al Viro8d71db42013-03-19 21:01:03 -04001013 if (opcode == IOCB_CMD_PWRITEV)
1014 file_start_write(file);
Zach Brown897f15f2005-09-30 11:58:55 -07001015 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001016 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1017 iocb->ki_nr_segs - iocb->ki_cur_seg,
1018 iocb->ki_pos);
1019 if (ret > 0)
1020 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001021
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001022 /* retry all partial writes. retry partial reads as long as its a
1023 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001024 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001025 (opcode == IOCB_CMD_PWRITEV ||
1026 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Al Viro8d71db42013-03-19 21:01:03 -04001027 if (opcode == IOCB_CMD_PWRITEV)
1028 file_end_write(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029
1030 /* This means we must have transferred all that we could */
1031 /* No need to retry anymore */
1032 if ((ret == 0) || (iocb->ki_left == 0))
1033 ret = iocb->ki_nbytes - iocb->ki_left;
1034
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001035 /* If we managed to write some out we return that, rather than
1036 * the eventual error. */
1037 if (opcode == IOCB_CMD_PWRITEV
Zach Brown41003a72013-05-07 16:18:25 -07001038 && ret < 0 && ret != -EIOCBQUEUED
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001039 && iocb->ki_nbytes - iocb->ki_left)
1040 ret = iocb->ki_nbytes - iocb->ki_left;
1041
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 return ret;
1043}
1044
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045static ssize_t aio_fdsync(struct kiocb *iocb)
1046{
1047 struct file *file = iocb->ki_filp;
1048 ssize_t ret = -EINVAL;
1049
1050 if (file->f_op->aio_fsync)
1051 ret = file->f_op->aio_fsync(iocb, 1);
1052 return ret;
1053}
1054
1055static ssize_t aio_fsync(struct kiocb *iocb)
1056{
1057 struct file *file = iocb->ki_filp;
1058 ssize_t ret = -EINVAL;
1059
1060 if (file->f_op->aio_fsync)
1061 ret = file->f_op->aio_fsync(iocb, 0);
1062 return ret;
1063}
1064
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001065static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001066{
1067 ssize_t ret;
1068
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001069#ifdef CONFIG_COMPAT
1070 if (compat)
1071 ret = compat_rw_copy_check_uvector(type,
1072 (struct compat_iovec __user *)kiocb->ki_buf,
1073 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohac34ebb2012-05-31 16:26:42 -07001074 &kiocb->ki_iovec);
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001075 else
1076#endif
1077 ret = rw_copy_check_uvector(type,
1078 (struct iovec __user *)kiocb->ki_buf,
1079 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
Christopher Yeohac34ebb2012-05-31 16:26:42 -07001080 &kiocb->ki_iovec);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001081 if (ret < 0)
1082 goto out;
1083
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001084 ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret);
1085 if (ret < 0)
1086 goto out;
1087
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001088 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1089 kiocb->ki_cur_seg = 0;
1090 /* ki_nbytes/left now reflect bytes instead of segs */
1091 kiocb->ki_nbytes = ret;
1092 kiocb->ki_left = ret;
1093
1094 ret = 0;
1095out:
1096 return ret;
1097}
1098
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001099static ssize_t aio_setup_single_vector(int type, struct file * file, struct kiocb *kiocb)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001100{
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001101 int bytes;
1102
1103 bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left);
1104 if (bytes < 0)
1105 return bytes;
1106
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001107 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1108 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001109 kiocb->ki_iovec->iov_len = bytes;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001110 kiocb->ki_nr_segs = 1;
1111 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001112 return 0;
1113}
1114
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115/*
1116 * aio_setup_iocb:
1117 * Performs the initial checks and aio retry method
1118 * setup for the kiocb at the time of io submission.
1119 */
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001120static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121{
1122 struct file *file = kiocb->ki_filp;
1123 ssize_t ret = 0;
1124
1125 switch (kiocb->ki_opcode) {
1126 case IOCB_CMD_PREAD:
1127 ret = -EBADF;
1128 if (unlikely(!(file->f_mode & FMODE_READ)))
1129 break;
1130 ret = -EFAULT;
1131 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1132 kiocb->ki_left)))
1133 break;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001134 ret = aio_setup_single_vector(READ, file, kiocb);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001135 if (ret)
1136 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 ret = -EINVAL;
1138 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001139 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 break;
1141 case IOCB_CMD_PWRITE:
1142 ret = -EBADF;
1143 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1144 break;
1145 ret = -EFAULT;
1146 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1147 kiocb->ki_left)))
1148 break;
Linus Torvaldsa70b52e2012-05-21 16:06:20 -07001149 ret = aio_setup_single_vector(WRITE, file, kiocb);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001150 if (ret)
1151 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 ret = -EINVAL;
1153 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001154 kiocb->ki_retry = aio_rw_vect_retry;
1155 break;
1156 case IOCB_CMD_PREADV:
1157 ret = -EBADF;
1158 if (unlikely(!(file->f_mode & FMODE_READ)))
1159 break;
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001160 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001161 if (ret)
1162 break;
1163 ret = -EINVAL;
1164 if (file->f_op->aio_read)
1165 kiocb->ki_retry = aio_rw_vect_retry;
1166 break;
1167 case IOCB_CMD_PWRITEV:
1168 ret = -EBADF;
1169 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1170 break;
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001171 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001172 if (ret)
1173 break;
1174 ret = -EINVAL;
1175 if (file->f_op->aio_write)
1176 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 break;
1178 case IOCB_CMD_FDSYNC:
1179 ret = -EINVAL;
1180 if (file->f_op->aio_fsync)
1181 kiocb->ki_retry = aio_fdsync;
1182 break;
1183 case IOCB_CMD_FSYNC:
1184 ret = -EINVAL;
1185 if (file->f_op->aio_fsync)
1186 kiocb->ki_retry = aio_fsync;
1187 break;
1188 default:
1189 dprintk("EINVAL: io_submit: no operation provided\n");
1190 ret = -EINVAL;
1191 }
1192
1193 if (!kiocb->ki_retry)
1194 return ret;
1195
1196 return 0;
1197}
1198
Adrian Bunkd5470b52008-04-29 00:58:57 -07001199static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer080d6762011-11-02 13:40:10 -07001200 struct iocb *iocb, struct kiocb_batch *batch,
1201 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202{
1203 struct kiocb *req;
1204 struct file *file;
1205 ssize_t ret;
1206
1207 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001208 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 pr_debug("EINVAL: io_submit: reserve field set\n");
1210 return -EINVAL;
1211 }
1212
1213 /* prevent overflows */
1214 if (unlikely(
1215 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1216 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1217 ((ssize_t)iocb->aio_nbytes < 0)
1218 )) {
1219 pr_debug("EINVAL: io_submit: overflow check\n");
1220 return -EINVAL;
1221 }
1222
1223 file = fget(iocb->aio_fildes);
1224 if (unlikely(!file))
1225 return -EBADF;
1226
Jeff Moyer080d6762011-11-02 13:40:10 -07001227 req = aio_get_req(ctx, batch); /* returns with 2 references to req */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 if (unlikely(!req)) {
1229 fput(file);
1230 return -EAGAIN;
1231 }
Yan Zheng87e28312007-10-08 12:16:20 -07001232 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001233 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1234 /*
1235 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1236 * instance of the file* now. The file descriptor must be
1237 * an eventfd() fd, and will be signaled for each completed
1238 * event using the eventfd_signal() function.
1239 */
Davide Libenzi13389012009-06-30 11:41:11 -07001240 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001241 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001242 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001243 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001244 goto out_put_req;
1245 }
1246 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247
Ken Chen212079c2005-05-01 08:59:15 -07001248 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 if (unlikely(ret)) {
1250 dprintk("EFAULT: aio_key\n");
1251 goto out_put_req;
1252 }
1253
1254 req->ki_obj.user = user_iocb;
1255 req->ki_user_data = iocb->aio_data;
1256 req->ki_pos = iocb->aio_offset;
1257
1258 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1259 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1260 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001262 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263
1264 if (ret)
1265 goto out_put_req;
1266
1267 spin_lock_irq(&ctx->ctx_lock);
Jan Kara7137c6bd2011-02-25 14:44:27 -08001268 /*
1269 * We could have raced with io_destroy() and are currently holding a
1270 * reference to ctx which should be destroyed. We cannot submit IO
1271 * since ctx gets freed as soon as io_submit() puts its reference. The
1272 * check here is reliable: io_destroy() sets ctx->dead before waiting
1273 * for outstanding IO and the barrier between these two is realized by
1274 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1275 * increment ctx->reqs_active before checking for ctx->dead and the
1276 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1277 * don't see ctx->dead set here, io_destroy() waits for our IO to
1278 * finish.
1279 */
Zach Brown41003a72013-05-07 16:18:25 -07001280 if (ctx->dead)
Jan Kara7137c6bd2011-02-25 14:44:27 -08001281 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown41003a72013-05-07 16:18:25 -07001283 if (ret)
1284 goto out_put_req;
1285
1286 if (unlikely(kiocbIsCancelled(req)))
1287 ret = -EINTR;
1288 else
1289 ret = req->ki_retry(req);
1290
1291 if (ret != -EIOCBQUEUED) {
1292 /*
1293 * There's no easy way to restart the syscall since other AIO's
1294 * may be already running. Just fail this IO with EINTR.
1295 */
1296 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
1297 ret == -ERESTARTNOHAND ||
1298 ret == -ERESTART_RESTARTBLOCK))
1299 ret = -EINTR;
1300 aio_complete(req, ret, 0);
1301 }
Jeff Moyercfb1e332009-10-02 18:57:36 -04001302
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 aio_put_req(req); /* drop extra ref to req */
1304 return 0;
1305
1306out_put_req:
1307 aio_put_req(req); /* drop extra ref to req */
1308 aio_put_req(req); /* drop i/o ref to req */
1309 return ret;
1310}
1311
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001312long do_io_submit(aio_context_t ctx_id, long nr,
1313 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314{
1315 struct kioctx *ctx;
1316 long ret = 0;
Jeff Moyer080d6762011-11-02 13:40:10 -07001317 int i = 0;
Shaohua Li9f5b9422010-07-01 07:55:01 +02001318 struct blk_plug plug;
Jeff Moyer080d6762011-11-02 13:40:10 -07001319 struct kiocb_batch batch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320
1321 if (unlikely(nr < 0))
1322 return -EINVAL;
1323
Jeff Moyer75e1c702010-09-10 14:16:00 -07001324 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1325 nr = LONG_MAX/sizeof(*iocbpp);
1326
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1328 return -EFAULT;
1329
1330 ctx = lookup_ioctx(ctx_id);
1331 if (unlikely(!ctx)) {
1332 pr_debug("EINVAL: io_submit: invalid context id\n");
1333 return -EINVAL;
1334 }
1335
Jeff Moyer080d6762011-11-02 13:40:10 -07001336 kiocb_batch_init(&batch, nr);
1337
Shaohua Li9f5b9422010-07-01 07:55:01 +02001338 blk_start_plug(&plug);
1339
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 /*
1341 * AKPM: should this return a partial result if some of the IOs were
1342 * successfully submitted?
1343 */
1344 for (i=0; i<nr; i++) {
1345 struct iocb __user *user_iocb;
1346 struct iocb tmp;
1347
1348 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1349 ret = -EFAULT;
1350 break;
1351 }
1352
1353 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1354 ret = -EFAULT;
1355 break;
1356 }
1357
Jeff Moyer080d6762011-11-02 13:40:10 -07001358 ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 if (ret)
1360 break;
1361 }
Shaohua Li9f5b9422010-07-01 07:55:01 +02001362 blk_finish_plug(&plug);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363
Gleb Natapov69e47472012-01-08 17:07:28 +02001364 kiocb_batch_free(ctx, &batch);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 put_ioctx(ctx);
1366 return i ? i : ret;
1367}
1368
Jeff Moyer9d85cba72010-05-26 14:44:26 -07001369/* sys_io_submit:
1370 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1371 * the number of iocbs queued. May return -EINVAL if the aio_context
1372 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1373 * *iocbpp[0] is not properly initialized, if the operation specified
1374 * is invalid for the file descriptor in the iocb. May fail with
1375 * -EFAULT if any of the data structures point to invalid data. May
1376 * fail with -EBADF if the file descriptor specified in the first
1377 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1378 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1379 * fail with -ENOSYS if not implemented.
1380 */
1381SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1382 struct iocb __user * __user *, iocbpp)
1383{
1384 return do_io_submit(ctx_id, nr, iocbpp, 0);
1385}
1386
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387/* lookup_kiocb
1388 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001390static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1391 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392{
1393 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001394
1395 assert_spin_locked(&ctx->ctx_lock);
1396
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 /* TODO: use a hash or array, this sucks. */
1398 list_for_each(pos, &ctx->active_reqs) {
1399 struct kiocb *kiocb = list_kiocb(pos);
1400 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1401 return kiocb;
1402 }
1403 return NULL;
1404}
1405
1406/* sys_io_cancel:
1407 * Attempts to cancel an iocb previously passed to io_submit. If
1408 * the operation is successfully cancelled, the resulting event is
1409 * copied into the memory pointed to by result without being placed
1410 * into the completion queue and 0 is returned. May fail with
1411 * -EFAULT if any of the data structures pointed to are invalid.
1412 * May fail with -EINVAL if aio_context specified by ctx_id is
1413 * invalid. May fail with -EAGAIN if the iocb specified was not
1414 * cancelled. Will fail with -ENOSYS if not implemented.
1415 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001416SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1417 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418{
1419 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1420 struct kioctx *ctx;
1421 struct kiocb *kiocb;
1422 u32 key;
1423 int ret;
1424
1425 ret = get_user(key, &iocb->aio_key);
1426 if (unlikely(ret))
1427 return -EFAULT;
1428
1429 ctx = lookup_ioctx(ctx_id);
1430 if (unlikely(!ctx))
1431 return -EINVAL;
1432
1433 spin_lock_irq(&ctx->ctx_lock);
1434 ret = -EAGAIN;
1435 kiocb = lookup_kiocb(ctx, iocb, key);
1436 if (kiocb && kiocb->ki_cancel) {
1437 cancel = kiocb->ki_cancel;
1438 kiocb->ki_users ++;
1439 kiocbSetCancelled(kiocb);
1440 } else
1441 cancel = NULL;
1442 spin_unlock_irq(&ctx->ctx_lock);
1443
1444 if (NULL != cancel) {
1445 struct io_event tmp;
1446 pr_debug("calling cancel\n");
1447 memset(&tmp, 0, sizeof(tmp));
1448 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1449 tmp.data = kiocb->ki_user_data;
1450 ret = cancel(kiocb, &tmp);
1451 if (!ret) {
1452 /* Cancellation succeeded -- copy the result
1453 * into the user's buffer.
1454 */
1455 if (copy_to_user(result, &tmp, sizeof(tmp)))
1456 ret = -EFAULT;
1457 }
1458 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001459 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
1461 put_ioctx(ctx);
1462
1463 return ret;
1464}
1465
1466/* io_getevents:
1467 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001468 * the completion queue for the aio_context specified by ctx_id. If
1469 * it succeeds, the number of read events is returned. May fail with
1470 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1471 * out of range, if timeout is out of range. May fail with -EFAULT
1472 * if any of the memory specified is invalid. May return 0 or
1473 * < min_nr if the timeout specified by timeout has elapsed
1474 * before sufficient events are available, where timeout == NULL
1475 * specifies an infinite timeout. Note that the timeout pointed to by
1476 * timeout is relative and will be updated if not NULL and the
1477 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001479SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1480 long, min_nr,
1481 long, nr,
1482 struct io_event __user *, events,
1483 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484{
1485 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1486 long ret = -EINVAL;
1487
1488 if (likely(ioctx)) {
Namhyung Kim2e410252011-01-12 17:01:08 -08001489 if (likely(min_nr <= nr && min_nr >= 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 ret = read_events(ioctx, min_nr, nr, events, timeout);
1491 put_ioctx(ioctx);
1492 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 return ret;
1494}