blob: 8c8f6c5b6d7930657f7a3aadf44fe4b4dc96b738 [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>
16#include <linux/module.h>
17#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>
37#include <linux/mempool.h>
38#include <linux/hash.h>
Jeff Moyer9d85cba2010-05-26 14:44:26 -070039#include <linux/compat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41#include <asm/kmap_types.h>
42#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44#if DEBUG > 1
45#define dprintk printk
46#else
47#define dprintk(x...) do { ; } while (0)
48#endif
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*------ sysctl variables----*/
Zach Brownd55b5fd2005-11-07 00:59:31 -080051static DEFINE_SPINLOCK(aio_nr_lock);
52unsigned long aio_nr; /* current system wide number of aio requests */
53unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
Linus Torvalds1da177e2005-04-16 15:20:36 -070054/*----end sysctl variables---*/
55
Christoph Lametere18b8902006-12-06 20:33:20 -080056static struct kmem_cache *kiocb_cachep;
57static struct kmem_cache *kioctx_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59static struct workqueue_struct *aio_wq;
60
61/* Used for rare fput completion. */
David Howells65f27f32006-11-22 14:55:48 +000062static void aio_fput_routine(struct work_struct *);
63static DECLARE_WORK(fput_work, aio_fput_routine);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65static DEFINE_SPINLOCK(fput_lock);
Adrian Bunk25ee7e32005-04-25 08:18:14 -070066static LIST_HEAD(fput_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Jeff Moyercfb1e332009-10-02 18:57:36 -040068#define AIO_BATCH_HASH_BITS 3 /* allocated on-stack, so don't go crazy */
69#define AIO_BATCH_HASH_SIZE (1 << AIO_BATCH_HASH_BITS)
70struct aio_batch_entry {
71 struct hlist_node list;
72 struct address_space *mapping;
73};
74mempool_t *abe_pool;
75
David Howells65f27f32006-11-22 14:55:48 +000076static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070077static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79/* aio_setup
80 * Creates the slab caches used by the aio routines, panic on
81 * failure as this is done early during the boot sequence.
82 */
83static int __init aio_setup(void)
84{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070085 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
86 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
88 aio_wq = create_workqueue("aio");
Jeff Moyercfb1e332009-10-02 18:57:36 -040089 abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry));
90 BUG_ON(!abe_pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
93
94 return 0;
95}
H Hartley Sweeten385773e2009-09-22 16:43:53 -070096__initcall(aio_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98static void aio_free_ring(struct kioctx *ctx)
99{
100 struct aio_ring_info *info = &ctx->ring_info;
101 long i;
102
103 for (i=0; i<info->nr_pages; i++)
104 put_page(info->ring_pages[i]);
105
106 if (info->mmap_size) {
107 down_write(&ctx->mm->mmap_sem);
108 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
109 up_write(&ctx->mm->mmap_sem);
110 }
111
112 if (info->ring_pages && info->ring_pages != info->internal_pages)
113 kfree(info->ring_pages);
114 info->ring_pages = NULL;
115 info->nr = 0;
116}
117
118static int aio_setup_ring(struct kioctx *ctx)
119{
120 struct aio_ring *ring;
121 struct aio_ring_info *info = &ctx->ring_info;
122 unsigned nr_events = ctx->max_reqs;
123 unsigned long size;
124 int nr_pages;
125
126 /* Compensate for the ring buffer's head/tail overlap entry */
127 nr_events += 2; /* 1 is required, 2 for good luck */
128
129 size = sizeof(struct aio_ring);
130 size += sizeof(struct io_event) * nr_events;
131 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
132
133 if (nr_pages < 0)
134 return -EINVAL;
135
136 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
137
138 info->nr = 0;
139 info->ring_pages = info->internal_pages;
140 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800141 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 if (!info->ring_pages)
143 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 }
145
146 info->mmap_size = nr_pages * PAGE_SIZE;
147 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
148 down_write(&ctx->mm->mmap_sem);
149 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
Robert P. J. Daye10a4432007-02-10 01:42:56 -0800150 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 0);
152 if (IS_ERR((void *)info->mmap_base)) {
153 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 info->mmap_size = 0;
155 aio_free_ring(ctx);
156 return -EAGAIN;
157 }
158
159 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
160 info->nr_pages = get_user_pages(current, ctx->mm,
161 info->mmap_base, nr_pages,
162 1, 0, info->ring_pages, NULL);
163 up_write(&ctx->mm->mmap_sem);
164
165 if (unlikely(info->nr_pages != nr_pages)) {
166 aio_free_ring(ctx);
167 return -EAGAIN;
168 }
169
170 ctx->user_id = info->mmap_base;
171
172 info->nr = nr_events; /* trusted copy */
173
174 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
175 ring->nr = nr_events; /* user copy */
176 ring->id = ctx->user_id;
177 ring->head = ring->tail = 0;
178 ring->magic = AIO_RING_MAGIC;
179 ring->compat_features = AIO_RING_COMPAT_FEATURES;
180 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
181 ring->header_length = sizeof(struct aio_ring);
182 kunmap_atomic(ring, KM_USER0);
183
184 return 0;
185}
186
187
188/* aio_ring_event: returns a pointer to the event at the given index from
189 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
190 */
191#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
192#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
193#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
194
195#define aio_ring_event(info, nr, km) ({ \
196 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
197 struct io_event *__event; \
198 __event = kmap_atomic( \
199 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
200 __event += pos % AIO_EVENTS_PER_PAGE; \
201 __event; \
202})
203
204#define put_aio_ring_event(event, km) do { \
205 struct io_event *__event = (event); \
206 (void)__event; \
207 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
208} while(0)
209
Jens Axboeabf137d2008-12-09 08:11:22 +0100210static void ctx_rcu_free(struct rcu_head *head)
Adrian Bunkd5470b52008-04-29 00:58:57 -0700211{
Jens Axboeabf137d2008-12-09 08:11:22 +0100212 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
Adrian Bunkd5470b52008-04-29 00:58:57 -0700213 unsigned nr_events = ctx->max_reqs;
214
Adrian Bunkd5470b52008-04-29 00:58:57 -0700215 kmem_cache_free(kioctx_cachep, ctx);
216
217 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 }
223}
224
Jens Axboeabf137d2008-12-09 08:11:22 +0100225/* __put_ioctx
226 * Called when the last user of an aio context has gone away,
227 * and the struct needs to be freed.
228 */
229static void __put_ioctx(struct kioctx *ctx)
230{
231 BUG_ON(ctx->reqs_active);
232
233 cancel_delayed_work(&ctx->wq);
234 cancel_work_sync(&ctx->wq.work);
235 aio_free_ring(ctx);
236 mmdrop(ctx->mm);
237 ctx->mm = NULL;
238 pr_debug("__put_ioctx: freeing %p\n", ctx);
239 call_rcu(&ctx->rcu_head, ctx_rcu_free);
240}
241
Adrian Bunkd5470b52008-04-29 00:58:57 -0700242#define get_ioctx(kioctx) do { \
243 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
244 atomic_inc(&(kioctx)->users); \
245} while (0)
246#define put_ioctx(kioctx) do { \
247 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
248 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
249 __put_ioctx(kioctx); \
250} while (0)
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252/* ioctx_alloc
253 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
254 */
255static struct kioctx *ioctx_alloc(unsigned nr_events)
256{
257 struct mm_struct *mm;
258 struct kioctx *ctx;
Jens Axboeabf137d2008-12-09 08:11:22 +0100259 int did_sync = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 /* Prevent overflows */
262 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
263 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
264 pr_debug("ENOMEM: nr_events too high\n");
265 return ERR_PTR(-EINVAL);
266 }
267
Zach Brownd55b5fd2005-11-07 00:59:31 -0800268 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 return ERR_PTR(-EAGAIN);
270
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800271 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 if (!ctx)
273 return ERR_PTR(-ENOMEM);
274
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 ctx->max_reqs = nr_events;
276 mm = ctx->mm = current->mm;
277 atomic_inc(&mm->mm_count);
278
279 atomic_set(&ctx->users, 1);
280 spin_lock_init(&ctx->ctx_lock);
281 spin_lock_init(&ctx->ring_info.ring_lock);
282 init_waitqueue_head(&ctx->wait);
283
284 INIT_LIST_HEAD(&ctx->active_reqs);
285 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000286 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
288 if (aio_setup_ring(ctx) < 0)
289 goto out_freectx;
290
291 /* limit the number of system wide aios */
Jens Axboeabf137d2008-12-09 08:11:22 +0100292 do {
293 spin_lock_bh(&aio_nr_lock);
294 if (aio_nr + nr_events > aio_max_nr ||
295 aio_nr + nr_events < aio_nr)
296 ctx->max_reqs = 0;
297 else
298 aio_nr += ctx->max_reqs;
299 spin_unlock_bh(&aio_nr_lock);
300 if (ctx->max_reqs || did_sync)
301 break;
302
303 /* wait for rcu callbacks to have completed before giving up */
304 synchronize_rcu();
305 did_sync = 1;
306 ctx->max_reqs = nr_events;
307 } while (1);
308
Zach Brownd55b5fd2005-11-07 00:59:31 -0800309 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 goto out_cleanup;
311
Jeff Moyer39fa0032008-04-29 01:03:48 -0700312 /* now link into global list. */
Jens Axboeabf137d2008-12-09 08:11:22 +0100313 spin_lock(&mm->ioctx_lock);
314 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
315 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
317 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
318 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
319 return ctx;
320
321out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 __put_ioctx(ctx);
323 return ERR_PTR(-EAGAIN);
324
325out_freectx:
326 mmdrop(mm);
327 kmem_cache_free(kioctx_cachep, ctx);
328 ctx = ERR_PTR(-ENOMEM);
329
330 dprintk("aio: error allocating ioctx %p\n", ctx);
331 return ctx;
332}
333
334/* aio_cancel_all
335 * Cancels all outstanding aio requests on an aio context. Used
336 * when the processes owning a context have all exited to encourage
337 * the rapid destruction of the kioctx.
338 */
339static void aio_cancel_all(struct kioctx *ctx)
340{
341 int (*cancel)(struct kiocb *, struct io_event *);
342 struct io_event res;
343 spin_lock_irq(&ctx->ctx_lock);
344 ctx->dead = 1;
345 while (!list_empty(&ctx->active_reqs)) {
346 struct list_head *pos = ctx->active_reqs.next;
347 struct kiocb *iocb = list_kiocb(pos);
348 list_del_init(&iocb->ki_list);
349 cancel = iocb->ki_cancel;
350 kiocbSetCancelled(iocb);
351 if (cancel) {
352 iocb->ki_users++;
353 spin_unlock_irq(&ctx->ctx_lock);
354 cancel(iocb, &res);
355 spin_lock_irq(&ctx->ctx_lock);
356 }
357 }
358 spin_unlock_irq(&ctx->ctx_lock);
359}
360
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700361static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362{
363 struct task_struct *tsk = current;
364 DECLARE_WAITQUEUE(wait, tsk);
365
Ken Chendee11c22007-02-03 01:13:45 -0800366 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800368 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
370 add_wait_queue(&ctx->wait, &wait);
371 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
372 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800373 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700374 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800376 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 }
378 __set_task_state(tsk, TASK_RUNNING);
379 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800380
381out:
382 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383}
384
385/* wait_on_sync_kiocb:
386 * Waits on the given sync kiocb to complete.
387 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800388ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389{
390 while (iocb->ki_users) {
391 set_current_state(TASK_UNINTERRUPTIBLE);
392 if (!iocb->ki_users)
393 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700394 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 }
396 __set_current_state(TASK_RUNNING);
397 return iocb->ki_user_data;
398}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700399EXPORT_SYMBOL(wait_on_sync_kiocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
401/* exit_aio: called when the last user of mm goes away. At this point,
402 * there is no way for any new requests to be submited or any of the
403 * io_* syscalls to be called on the context. However, there may be
404 * outstanding requests which hold references to the context; as they
405 * go away, they will call put_ioctx and release any pinned memory
406 * associated with the request (held via struct page * references).
407 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800408void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409{
Jens Axboeabf137d2008-12-09 08:11:22 +0100410 struct kioctx *ctx;
411
412 while (!hlist_empty(&mm->ioctx_list)) {
413 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
414 hlist_del_rcu(&ctx->list);
415
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 aio_cancel_all(ctx);
417
418 wait_for_all_aios(ctx);
419 /*
Andrew Mortona9df62c2007-05-09 02:33:54 -0700420 * Ensure we don't leave the ctx on the aio_wq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 */
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700422 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
424 if (1 != atomic_read(&ctx->users))
425 printk(KERN_DEBUG
426 "exit_aio:ioctx still alive: %d %d %d\n",
427 atomic_read(&ctx->users), ctx->dead,
428 ctx->reqs_active);
429 put_ioctx(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 }
431}
432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433/* aio_get_req
434 * Allocate a slot for an aio request. Increments the users count
435 * of the kioctx so that the kioctx stays around until all requests are
436 * complete. Returns NULL if no requests are free.
437 *
438 * Returns with kiocb->users set to 2. The io submit code path holds
439 * an extra reference while submitting the i/o.
440 * This prevents races between the aio code path referencing the
441 * req (after submitting it) and aio_complete() freeing the req.
442 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800443static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444{
445 struct kiocb *req = NULL;
446 struct aio_ring *ring;
447 int okay = 0;
448
449 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
450 if (unlikely(!req))
451 return NULL;
452
Zach Brown4faa5282005-10-17 16:43:33 -0700453 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 req->ki_users = 2;
455 req->ki_key = 0;
456 req->ki_ctx = ctx;
457 req->ki_cancel = NULL;
458 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 req->ki_dtor = NULL;
460 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700461 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi87c3a862009-03-18 17:04:19 -0700463 req->ki_eventfd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
465 /* Check if the completion queue has enough free space to
466 * accept an event from this io.
467 */
468 spin_lock_irq(&ctx->ctx_lock);
469 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
470 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
471 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 ctx->reqs_active++;
473 okay = 1;
474 }
475 kunmap_atomic(ring, KM_USER0);
476 spin_unlock_irq(&ctx->ctx_lock);
477
478 if (!okay) {
479 kmem_cache_free(kiocb_cachep, req);
480 req = NULL;
481 }
482
483 return req;
484}
485
486static inline struct kiocb *aio_get_req(struct kioctx *ctx)
487{
488 struct kiocb *req;
489 /* Handle a potential starvation case -- should be exceedingly rare as
490 * requests will be stuck on fput_head only if the aio_fput_routine is
491 * delayed and the requests were the last user of the struct file.
492 */
493 req = __aio_get_req(ctx);
494 if (unlikely(NULL == req)) {
495 aio_fput_routine(NULL);
496 req = __aio_get_req(ctx);
497 }
498 return req;
499}
500
501static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
502{
Zach Brownd00689a2005-11-13 16:07:34 -0800503 assert_spin_locked(&ctx->ctx_lock);
504
Davide Libenzi13389012009-06-30 11:41:11 -0700505 if (req->ki_eventfd != NULL)
506 eventfd_ctx_put(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 if (req->ki_dtor)
508 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700509 if (req->ki_iovec != &req->ki_inline_vec)
510 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 kmem_cache_free(kiocb_cachep, req);
512 ctx->reqs_active--;
513
514 if (unlikely(!ctx->reqs_active && ctx->dead))
515 wake_up(&ctx->wait);
516}
517
David Howells65f27f32006-11-22 14:55:48 +0000518static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519{
520 spin_lock_irq(&fput_lock);
521 while (likely(!list_empty(&fput_head))) {
522 struct kiocb *req = list_kiocb(fput_head.next);
523 struct kioctx *ctx = req->ki_ctx;
524
525 list_del(&req->ki_list);
526 spin_unlock_irq(&fput_lock);
527
Davide Libenzi87c3a862009-03-18 17:04:19 -0700528 /* Complete the fput(s) */
529 if (req->ki_filp != NULL)
Al Virod7065da2010-05-26 15:13:55 -0400530 fput(req->ki_filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
532 /* Link the iocb into the context's free list */
533 spin_lock_irq(&ctx->ctx_lock);
534 really_put_req(ctx, req);
535 spin_unlock_irq(&ctx->ctx_lock);
536
537 put_ioctx(ctx);
538 spin_lock_irq(&fput_lock);
539 }
540 spin_unlock_irq(&fput_lock);
541}
542
543/* __aio_put_req
544 * Returns true if this put was the last user of the request.
545 */
546static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
547{
Al Viro516e0cc2008-07-26 00:39:17 -0400548 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
549 req, atomic_long_read(&req->ki_filp->f_count));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550
Zach Brownd00689a2005-11-13 16:07:34 -0800551 assert_spin_locked(&ctx->ctx_lock);
552
Davide Libenzi87c3a862009-03-18 17:04:19 -0700553 req->ki_users--;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100554 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 if (likely(req->ki_users))
556 return 0;
557 list_del(&req->ki_list); /* remove from active_reqs */
558 req->ki_cancel = NULL;
559 req->ki_retry = NULL;
560
Davide Libenzi87c3a862009-03-18 17:04:19 -0700561 /*
562 * Try to optimize the aio and eventfd file* puts, by avoiding to
Al Virod7065da2010-05-26 15:13:55 -0400563 * schedule work in case it is not final fput() time. In normal cases,
Davide Libenzi87c3a862009-03-18 17:04:19 -0700564 * we would not be holding the last reference to the file*, so
565 * this function will be executed w/out any aio kthread wakeup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 */
Al Virod7065da2010-05-26 15:13:55 -0400567 if (unlikely(!fput_atomic(req->ki_filp))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 get_ioctx(ctx);
569 spin_lock(&fput_lock);
570 list_add(&req->ki_list, &fput_head);
571 spin_unlock(&fput_lock);
572 queue_work(aio_wq, &fput_work);
Davide Libenzi13389012009-06-30 11:41:11 -0700573 } else {
574 req->ki_filp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 really_put_req(ctx, req);
Davide Libenzi13389012009-06-30 11:41:11 -0700576 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 return 1;
578}
579
580/* aio_put_req
581 * Returns true if this put was the last user of the kiocb,
582 * false if the request is still in use.
583 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800584int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
586 struct kioctx *ctx = req->ki_ctx;
587 int ret;
588 spin_lock_irq(&ctx->ctx_lock);
589 ret = __aio_put_req(ctx, req);
590 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 return ret;
592}
H Hartley Sweeten385773e2009-09-22 16:43:53 -0700593EXPORT_SYMBOL(aio_put_req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
Adrian Bunkd5470b52008-04-29 00:58:57 -0700595static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596{
Jens Axboeabf137d2008-12-09 08:11:22 +0100597 struct mm_struct *mm = current->mm;
Jeff Moyer65c24492009-03-18 17:04:21 -0700598 struct kioctx *ctx, *ret = NULL;
Jens Axboeabf137d2008-12-09 08:11:22 +0100599 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600
Jens Axboeabf137d2008-12-09 08:11:22 +0100601 rcu_read_lock();
602
603 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
604 if (ctx->user_id == ctx_id && !ctx->dead) {
605 get_ioctx(ctx);
Jeff Moyer65c24492009-03-18 17:04:21 -0700606 ret = ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 break;
608 }
Jens Axboeabf137d2008-12-09 08:11:22 +0100609 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
Jens Axboeabf137d2008-12-09 08:11:22 +0100611 rcu_read_unlock();
Jeff Moyer65c24492009-03-18 17:04:21 -0700612 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613}
614
615/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 * Queue up a kiocb to be retried. Assumes that the kiocb
617 * has already been marked as kicked, and places it on
618 * the retry run list for the corresponding ioctx, if it
619 * isn't already queued. Returns 1 if it actually queued
620 * the kiocb (to tell the caller to activate the work
621 * queue to process it), or 0, if it found that it was
622 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 */
624static inline int __queue_kicked_iocb(struct kiocb *iocb)
625{
626 struct kioctx *ctx = iocb->ki_ctx;
627
Zach Brownd00689a2005-11-13 16:07:34 -0800628 assert_spin_locked(&ctx->ctx_lock);
629
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 if (list_empty(&iocb->ki_run_list)) {
631 list_add_tail(&iocb->ki_run_list,
632 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return 1;
634 }
635 return 0;
636}
637
638/* aio_run_iocb
639 * This is the core aio execution routine. It is
640 * invoked both for initial i/o submission and
641 * subsequent retries via the aio_kick_handler.
642 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200643 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 * as needed during processing.
645 *
646 * Calls the iocb retry method (already setup for the
647 * iocb on initial submission) for operation specific
648 * handling, but takes care of most of common retry
649 * execution details for a given iocb. The retry method
650 * needs to be non-blocking as far as possible, to avoid
651 * holding up other iocbs waiting to be serviced by the
652 * retry kernel thread.
653 *
654 * The trickier parts in this code have to do with
655 * ensuring that only one retry instance is in progress
656 * for a given iocb at any time. Providing that guarantee
657 * simplifies the coding of individual aio operations as
658 * it avoids various potential races.
659 */
660static ssize_t aio_run_iocb(struct kiocb *iocb)
661{
662 struct kioctx *ctx = iocb->ki_ctx;
663 ssize_t (*retry)(struct kiocb *);
664 ssize_t ret;
665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 if (!(retry = iocb->ki_retry)) {
667 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
668 return 0;
669 }
670
671 /*
672 * We don't want the next retry iteration for this
673 * operation to start until this one has returned and
674 * updated the iocb state. However, wait_queue functions
675 * can trigger a kick_iocb from interrupt context in the
676 * meantime, indicating that data is available for the next
677 * iteration. We want to remember that and enable the
678 * next retry iteration _after_ we are through with
679 * this one.
680 *
681 * So, in order to be able to register a "kick", but
682 * prevent it from being queued now, we clear the kick
683 * flag, but make the kick code *think* that the iocb is
684 * still on the run list until we are actually done.
685 * When we are done with this iteration, we check if
686 * the iocb was kicked in the meantime and if so, queue
687 * it up afresh.
688 */
689
690 kiocbClearKicked(iocb);
691
692 /*
693 * This is so that aio_complete knows it doesn't need to
694 * pull the iocb off the run list (We can't just call
695 * INIT_LIST_HEAD because we don't want a kick_iocb to
696 * queue this on the run list yet)
697 */
698 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
699 spin_unlock_irq(&ctx->ctx_lock);
700
701 /* Quit retrying if the i/o has been cancelled */
702 if (kiocbIsCancelled(iocb)) {
703 ret = -EINTR;
704 aio_complete(iocb, ret, 0);
705 /* must not access the iocb after this */
706 goto out;
707 }
708
709 /*
710 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700711 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714
Jan Karaa0c42ba2010-09-22 13:05:03 -0700715 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
716 /*
717 * There's no easy way to restart the syscall since other AIO's
718 * may be already running. Just fail this IO with EINTR.
719 */
720 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
721 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
722 ret = -EINTR;
Zach Brown897f15f2005-09-30 11:58:55 -0700723 aio_complete(iocb, ret, 0);
Jan Karaa0c42ba2010-09-22 13:05:03 -0700724 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725out:
726 spin_lock_irq(&ctx->ctx_lock);
727
728 if (-EIOCBRETRY == ret) {
729 /*
730 * OK, now that we are done with this iteration
731 * and know that there is more left to go,
732 * this is where we let go so that a subsequent
733 * "kick" can start the next iteration
734 */
735
736 /* will make __queue_kicked_iocb succeed from here on */
737 INIT_LIST_HEAD(&iocb->ki_run_list);
738 /* we must queue the next iteration ourselves, if it
739 * has already been kicked */
740 if (kiocbIsKicked(iocb)) {
741 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700742
743 /*
744 * __queue_kicked_iocb will always return 1 here, because
745 * iocb->ki_run_list is empty at this point so it should
746 * be safe to unconditionally queue the context into the
747 * work queue.
748 */
749 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 }
751 }
752 return ret;
753}
754
755/*
756 * __aio_run_iocbs:
757 * Process all pending retries queued on the ioctx
758 * run list.
759 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800760 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 */
762static int __aio_run_iocbs(struct kioctx *ctx)
763{
764 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700765 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766
Zach Brownd00689a2005-11-13 16:07:34 -0800767 assert_spin_locked(&ctx->ctx_lock);
768
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700769 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 while (!list_empty(&run_list)) {
771 iocb = list_entry(run_list.next, struct kiocb,
772 ki_run_list);
773 list_del(&iocb->ki_run_list);
774 /*
775 * Hold an extra reference while retrying i/o.
776 */
777 iocb->ki_users++; /* grab extra reference */
778 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800779 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 if (!list_empty(&ctx->run_list))
782 return 1;
783 return 0;
784}
785
786static void aio_queue_work(struct kioctx * ctx)
787{
788 unsigned long timeout;
789 /*
790 * if someone is waiting, get the work started right
791 * away, otherwise, use a longer delay
792 */
793 smp_mb();
794 if (waitqueue_active(&ctx->wait))
795 timeout = 1;
796 else
797 timeout = HZ/10;
798 queue_delayed_work(aio_wq, &ctx->wq, timeout);
799}
800
801
802/*
803 * aio_run_iocbs:
804 * Process all pending retries queued on the ioctx
805 * run list.
806 * Assumes it is operating within the aio issuer's mm
807 * context.
808 */
809static inline void aio_run_iocbs(struct kioctx *ctx)
810{
811 int requeue;
812
813 spin_lock_irq(&ctx->ctx_lock);
814
815 requeue = __aio_run_iocbs(ctx);
816 spin_unlock_irq(&ctx->ctx_lock);
817 if (requeue)
818 aio_queue_work(ctx);
819}
820
821/*
822 * just like aio_run_iocbs, but keeps running them until
823 * the list stays empty
824 */
825static inline void aio_run_all_iocbs(struct kioctx *ctx)
826{
827 spin_lock_irq(&ctx->ctx_lock);
828 while (__aio_run_iocbs(ctx))
829 ;
830 spin_unlock_irq(&ctx->ctx_lock);
831}
832
833/*
834 * aio_kick_handler:
835 * Work queue handler triggered to process pending
836 * retries on an ioctx. Takes on the aio issuer's
837 * mm context before running the iocbs, so that
838 * copy_xxx_user operates on the issuer's address
839 * space.
840 * Run on aiod's context.
841 */
David Howells65f27f32006-11-22 14:55:48 +0000842static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843{
David Howells65f27f32006-11-22 14:55:48 +0000844 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800846 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 int requeue;
848
849 set_fs(USER_DS);
850 use_mm(ctx->mm);
851 spin_lock_irq(&ctx->ctx_lock);
852 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800853 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800855 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 set_fs(oldfs);
857 /*
858 * we're in a worker thread already, don't use queue_delayed_work,
859 */
860 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000861 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862}
863
864
865/*
866 * Called by kick_iocb to queue the kiocb for retry
867 * and if required activate the aio work queue to process
868 * it
869 */
Zach Brown998765e2005-09-30 11:58:54 -0700870static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871{
872 struct kioctx *ctx = iocb->ki_ctx;
873 unsigned long flags;
874 int run = 0;
875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700877 /* set this inside the lock so that we can't race with aio_run_iocb()
878 * testing it and putting the iocb on the run list under the lock */
879 if (!kiocbTryKick(iocb))
880 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700882 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884}
885
886/*
887 * kick_iocb:
888 * Called typically from a wait queue callback context
Shaohua Lifac046a2009-12-15 16:47:47 -0800889 * to trigger a retry of the iocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 * The retry is usually executed by aio workqueue
891 * threads (See aio_kick_handler).
892 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800893void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894{
895 /* sync iocbs are easy: they can only ever be executing from a
896 * single context. */
897 if (is_sync_kiocb(iocb)) {
898 kiocbSetKicked(iocb);
899 wake_up_process(iocb->ki_obj.tsk);
900 return;
901 }
902
Zach Brown998765e2005-09-30 11:58:54 -0700903 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904}
905EXPORT_SYMBOL(kick_iocb);
906
907/* aio_complete
908 * Called when the io request on the given iocb is complete.
909 * Returns true if this is the last user of the request. The
910 * only other user of the request can be the cancellation code.
911 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800912int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913{
914 struct kioctx *ctx = iocb->ki_ctx;
915 struct aio_ring_info *info;
916 struct aio_ring *ring;
917 struct io_event *event;
918 unsigned long flags;
919 unsigned long tail;
920 int ret;
921
Zach Brown20dcae32005-11-13 16:07:33 -0800922 /*
923 * Special case handling for sync iocbs:
924 * - events go directly into the iocb for fast handling
925 * - the sync task with the iocb in its stack holds the single iocb
926 * ref, no other paths have a way to get another ref
927 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 */
929 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800930 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800932 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800934 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 }
936
937 info = &ctx->ring_info;
938
939 /* add a completion event to the ring buffer.
940 * must be done holding ctx->ctx_lock to prevent
941 * other code from messing with the tail
942 * pointer since we might be called from irq
943 * context.
944 */
945 spin_lock_irqsave(&ctx->ctx_lock, flags);
946
947 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
948 list_del_init(&iocb->ki_run_list);
949
950 /*
951 * cancelled requests don't get events, userland was given one
952 * when the event got cancelled.
953 */
954 if (kiocbIsCancelled(iocb))
955 goto put_rq;
956
957 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
958
959 tail = info->tail;
960 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700961 if (++tail >= info->nr)
962 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963
964 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
965 event->data = iocb->ki_user_data;
966 event->res = res;
967 event->res2 = res2;
968
969 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
970 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
971 res, res2);
972
973 /* after flagging the request as done, we
974 * must never even look at it again
975 */
976 smp_wmb(); /* make event visible before updating tail */
977
978 info->tail = tail;
979 ring->tail = tail;
980
981 put_aio_ring_event(event, KM_IRQ0);
982 kunmap_atomic(ring, KM_IRQ1);
983
984 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700985
986 /*
987 * Check if the user asked us to deliver the result through an
988 * eventfd. The eventfd_signal() function is safe to be called
989 * from IRQ context.
990 */
Davide Libenzi87c3a862009-03-18 17:04:19 -0700991 if (iocb->ki_eventfd != NULL)
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700992 eventfd_signal(iocb->ki_eventfd, 1);
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994put_rq:
995 /* everything turned out well, dispose of the aiocb. */
996 ret = __aio_put_req(ctx, iocb);
997
Quentin Barnes6cb2a212008-03-19 17:00:39 -0700998 /*
999 * We have to order our ring_info tail store above and test
1000 * of the wait list below outside the wait lock. This is
1001 * like in wake_up_bit() where clearing a bit has to be
1002 * ordered with the unlocked test.
1003 */
1004 smp_mb();
1005
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 if (waitqueue_active(&ctx->wait))
1007 wake_up(&ctx->wait);
1008
Ken Chendee11c22007-02-03 01:13:45 -08001009 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 return ret;
1011}
H Hartley Sweeten385773e2009-09-22 16:43:53 -07001012EXPORT_SYMBOL(aio_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013
1014/* aio_read_evt
1015 * Pull an event off of the ioctx's event ring. Returns the number of
1016 * events fetched (0 or 1 ;-)
1017 * FIXME: make this use cmpxchg.
1018 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1019 */
1020static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1021{
1022 struct aio_ring_info *info = &ioctx->ring_info;
1023 struct aio_ring *ring;
1024 unsigned long head;
1025 int ret = 0;
1026
1027 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1028 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1029 (unsigned long)ring->head, (unsigned long)ring->tail,
1030 (unsigned long)ring->nr);
1031
1032 if (ring->head == ring->tail)
1033 goto out;
1034
1035 spin_lock(&info->ring_lock);
1036
1037 head = ring->head % info->nr;
1038 if (head != ring->tail) {
1039 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1040 *ent = *evp;
1041 head = (head + 1) % info->nr;
1042 smp_mb(); /* finish reading the event before updatng the head */
1043 ring->head = head;
1044 ret = 1;
1045 put_aio_ring_event(evp, KM_USER1);
1046 }
1047 spin_unlock(&info->ring_lock);
1048
1049out:
1050 kunmap_atomic(ring, KM_USER0);
1051 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1052 (unsigned long)ring->head, (unsigned long)ring->tail);
1053 return ret;
1054}
1055
1056struct aio_timeout {
1057 struct timer_list timer;
1058 int timed_out;
1059 struct task_struct *p;
1060};
1061
1062static void timeout_func(unsigned long data)
1063{
1064 struct aio_timeout *to = (struct aio_timeout *)data;
1065
1066 to->timed_out = 1;
1067 wake_up_process(to->p);
1068}
1069
1070static inline void init_timeout(struct aio_timeout *to)
1071{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001072 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 to->timed_out = 0;
1074 to->p = current;
1075}
1076
1077static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1078 const struct timespec *ts)
1079{
1080 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1081 if (time_after(to->timer.expires, jiffies))
1082 add_timer(&to->timer);
1083 else
1084 to->timed_out = 1;
1085}
1086
1087static inline void clear_timeout(struct aio_timeout *to)
1088{
1089 del_singleshot_timer_sync(&to->timer);
1090}
1091
1092static int read_events(struct kioctx *ctx,
1093 long min_nr, long nr,
1094 struct io_event __user *event,
1095 struct timespec __user *timeout)
1096{
1097 long start_jiffies = jiffies;
1098 struct task_struct *tsk = current;
1099 DECLARE_WAITQUEUE(wait, tsk);
1100 int ret;
1101 int i = 0;
1102 struct io_event ent;
1103 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 int retry = 0;
1105
1106 /* needed to zero any padding within an entry (there shouldn't be
1107 * any, but C is fun!
1108 */
1109 memset(&ent, 0, sizeof(ent));
1110retry:
1111 ret = 0;
1112 while (likely(i < nr)) {
1113 ret = aio_read_evt(ctx, &ent);
1114 if (unlikely(ret <= 0))
1115 break;
1116
1117 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1118 ent.data, ent.obj, ent.res, ent.res2);
1119
1120 /* Could we split the check in two? */
1121 ret = -EFAULT;
1122 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1123 dprintk("aio: lost an event due to EFAULT.\n");
1124 break;
1125 }
1126 ret = 0;
1127
1128 /* Good, event copied to userland, update counts. */
1129 event ++;
1130 i ++;
1131 }
1132
1133 if (min_nr <= i)
1134 return i;
1135 if (ret)
1136 return ret;
1137
1138 /* End fast path */
1139
1140 /* racey check, but it gets redone */
1141 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1142 retry = 1;
1143 aio_run_all_iocbs(ctx);
1144 goto retry;
1145 }
1146
1147 init_timeout(&to);
1148 if (timeout) {
1149 struct timespec ts;
1150 ret = -EFAULT;
1151 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1152 goto out;
1153
1154 set_timeout(start_jiffies, &to, &ts);
1155 }
1156
1157 while (likely(i < nr)) {
1158 add_wait_queue_exclusive(&ctx->wait, &wait);
1159 do {
1160 set_task_state(tsk, TASK_INTERRUPTIBLE);
1161 ret = aio_read_evt(ctx, &ent);
1162 if (ret)
1163 break;
1164 if (min_nr <= i)
1165 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001166 if (unlikely(ctx->dead)) {
1167 ret = -EINVAL;
1168 break;
1169 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 if (to.timed_out) /* Only check after read evt */
1171 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001172 /* Try to only show up in io wait if there are ops
1173 * in flight */
1174 if (ctx->reqs_active)
1175 io_schedule();
1176 else
1177 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 if (signal_pending(tsk)) {
1179 ret = -EINTR;
1180 break;
1181 }
1182 /*ret = aio_read_evt(ctx, &ent);*/
1183 } while (1) ;
1184
1185 set_task_state(tsk, TASK_RUNNING);
1186 remove_wait_queue(&ctx->wait, &wait);
1187
1188 if (unlikely(ret <= 0))
1189 break;
1190
1191 ret = -EFAULT;
1192 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1193 dprintk("aio: lost an event due to EFAULT.\n");
1194 break;
1195 }
1196
1197 /* Good, event copied to userland, update counts. */
1198 event ++;
1199 i ++;
1200 }
1201
1202 if (timeout)
1203 clear_timeout(&to);
1204out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001205 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 return i ? i : ret;
1207}
1208
1209/* Take an ioctx and remove it from the list of ioctx's. Protects
1210 * against races with itself via ->dead.
1211 */
1212static void io_destroy(struct kioctx *ioctx)
1213{
1214 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 int was_dead;
1216
1217 /* delete the entry from the list is someone else hasn't already */
Jens Axboeabf137d2008-12-09 08:11:22 +01001218 spin_lock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 was_dead = ioctx->dead;
1220 ioctx->dead = 1;
Jens Axboeabf137d2008-12-09 08:11:22 +01001221 hlist_del_rcu(&ioctx->list);
1222 spin_unlock(&mm->ioctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223
1224 dprintk("aio_release(%p)\n", ioctx);
1225 if (likely(!was_dead))
1226 put_ioctx(ioctx); /* twice for the list */
1227
1228 aio_cancel_all(ioctx);
1229 wait_for_all_aios(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001230
1231 /*
1232 * Wake up any waiters. The setting of ctx->dead must be seen
1233 * by other CPUs at this point. Right now, we rely on the
1234 * locking done by the above calls to ensure this consistency.
1235 */
1236 wake_up(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 put_ioctx(ioctx); /* once for the lookup */
1238}
1239
1240/* sys_io_setup:
1241 * Create an aio_context capable of receiving at least nr_events.
1242 * ctxp must not point to an aio_context that already exists, and
1243 * must be initialized to 0 prior to the call. On successful
1244 * creation of the aio_context, *ctxp is filled in with the resulting
1245 * handle. May fail with -EINVAL if *ctxp is not initialized,
1246 * if the specified nr_events exceeds internal limits. May fail
1247 * with -EAGAIN if the specified nr_events exceeds the user's limit
1248 * of available events. May fail with -ENOMEM if insufficient kernel
1249 * resources are available. May fail with -EFAULT if an invalid
1250 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1251 * implemented.
1252 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001253SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254{
1255 struct kioctx *ioctx = NULL;
1256 unsigned long ctx;
1257 long ret;
1258
1259 ret = get_user(ctx, ctxp);
1260 if (unlikely(ret))
1261 goto out;
1262
1263 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001264 if (unlikely(ctx || nr_events == 0)) {
1265 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1266 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 goto out;
1268 }
1269
1270 ioctx = ioctx_alloc(nr_events);
1271 ret = PTR_ERR(ioctx);
1272 if (!IS_ERR(ioctx)) {
1273 ret = put_user(ioctx->user_id, ctxp);
1274 if (!ret)
1275 return 0;
1276
1277 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1278 io_destroy(ioctx);
1279 }
1280
1281out:
1282 return ret;
1283}
1284
1285/* sys_io_destroy:
1286 * Destroy the aio_context specified. May cancel any outstanding
1287 * AIOs and block on completion. Will fail with -ENOSYS if not
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001288 * implemented. May fail with -EINVAL if the context pointed to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 * is invalid.
1290 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001291SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292{
1293 struct kioctx *ioctx = lookup_ioctx(ctx);
1294 if (likely(NULL != ioctx)) {
1295 io_destroy(ioctx);
1296 return 0;
1297 }
1298 pr_debug("EINVAL: io_destroy: invalid context id\n");
1299 return -EINVAL;
1300}
1301
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001302static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1303{
1304 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1305
1306 BUG_ON(ret <= 0);
1307
1308 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1309 ssize_t this = min((ssize_t)iov->iov_len, ret);
1310 iov->iov_base += this;
1311 iov->iov_len -= this;
1312 iocb->ki_left -= this;
1313 ret -= this;
1314 if (iov->iov_len == 0) {
1315 iocb->ki_cur_seg++;
1316 iov++;
1317 }
1318 }
1319
1320 /* the caller should not have done more io than what fit in
1321 * the remaining iovecs */
1322 BUG_ON(ret > 0 && iocb->ki_left == 0);
1323}
1324
1325static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326{
1327 struct file *file = iocb->ki_filp;
1328 struct address_space *mapping = file->f_mapping;
1329 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001330 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1331 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001333 unsigned short opcode;
1334
1335 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1336 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1337 rw_op = file->f_op->aio_read;
1338 opcode = IOCB_CMD_PREADV;
1339 } else {
1340 rw_op = file->f_op->aio_write;
1341 opcode = IOCB_CMD_PWRITEV;
1342 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Rusty Russellc2ec6682008-02-08 04:20:15 -08001344 /* This matches the pread()/pwrite() logic */
1345 if (iocb->ki_pos < 0)
1346 return -EINVAL;
1347
Zach Brown897f15f2005-09-30 11:58:55 -07001348 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001349 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1350 iocb->ki_nr_segs - iocb->ki_cur_seg,
1351 iocb->ki_pos);
1352 if (ret > 0)
1353 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001354
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001355 /* retry all partial writes. retry partial reads as long as its a
1356 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001357 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001358 (opcode == IOCB_CMD_PWRITEV ||
1359 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360
1361 /* This means we must have transferred all that we could */
1362 /* No need to retry anymore */
1363 if ((ret == 0) || (iocb->ki_left == 0))
1364 ret = iocb->ki_nbytes - iocb->ki_left;
1365
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001366 /* If we managed to write some out we return that, rather than
1367 * the eventual error. */
1368 if (opcode == IOCB_CMD_PWRITEV
1369 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1370 && iocb->ki_nbytes - iocb->ki_left)
1371 ret = iocb->ki_nbytes - iocb->ki_left;
1372
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373 return ret;
1374}
1375
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376static ssize_t aio_fdsync(struct kiocb *iocb)
1377{
1378 struct file *file = iocb->ki_filp;
1379 ssize_t ret = -EINVAL;
1380
1381 if (file->f_op->aio_fsync)
1382 ret = file->f_op->aio_fsync(iocb, 1);
1383 return ret;
1384}
1385
1386static ssize_t aio_fsync(struct kiocb *iocb)
1387{
1388 struct file *file = iocb->ki_filp;
1389 ssize_t ret = -EINVAL;
1390
1391 if (file->f_op->aio_fsync)
1392 ret = file->f_op->aio_fsync(iocb, 0);
1393 return ret;
1394}
1395
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001396static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001397{
1398 ssize_t ret;
1399
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001400#ifdef CONFIG_COMPAT
1401 if (compat)
1402 ret = compat_rw_copy_check_uvector(type,
1403 (struct compat_iovec __user *)kiocb->ki_buf,
1404 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
1405 &kiocb->ki_iovec);
1406 else
1407#endif
1408 ret = rw_copy_check_uvector(type,
1409 (struct iovec __user *)kiocb->ki_buf,
1410 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
1411 &kiocb->ki_iovec);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001412 if (ret < 0)
1413 goto out;
1414
1415 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1416 kiocb->ki_cur_seg = 0;
1417 /* ki_nbytes/left now reflect bytes instead of segs */
1418 kiocb->ki_nbytes = ret;
1419 kiocb->ki_left = ret;
1420
1421 ret = 0;
1422out:
1423 return ret;
1424}
1425
1426static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1427{
1428 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1429 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1430 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1431 kiocb->ki_nr_segs = 1;
1432 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001433 return 0;
1434}
1435
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436/*
1437 * aio_setup_iocb:
1438 * Performs the initial checks and aio retry method
1439 * setup for the kiocb at the time of io submission.
1440 */
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001441static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442{
1443 struct file *file = kiocb->ki_filp;
1444 ssize_t ret = 0;
1445
1446 switch (kiocb->ki_opcode) {
1447 case IOCB_CMD_PREAD:
1448 ret = -EBADF;
1449 if (unlikely(!(file->f_mode & FMODE_READ)))
1450 break;
1451 ret = -EFAULT;
1452 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1453 kiocb->ki_left)))
1454 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001455 ret = security_file_permission(file, MAY_READ);
1456 if (unlikely(ret))
1457 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001458 ret = aio_setup_single_vector(kiocb);
1459 if (ret)
1460 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 ret = -EINVAL;
1462 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001463 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 break;
1465 case IOCB_CMD_PWRITE:
1466 ret = -EBADF;
1467 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1468 break;
1469 ret = -EFAULT;
1470 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1471 kiocb->ki_left)))
1472 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001473 ret = security_file_permission(file, MAY_WRITE);
1474 if (unlikely(ret))
1475 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001476 ret = aio_setup_single_vector(kiocb);
1477 if (ret)
1478 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 ret = -EINVAL;
1480 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001481 kiocb->ki_retry = aio_rw_vect_retry;
1482 break;
1483 case IOCB_CMD_PREADV:
1484 ret = -EBADF;
1485 if (unlikely(!(file->f_mode & FMODE_READ)))
1486 break;
1487 ret = security_file_permission(file, MAY_READ);
1488 if (unlikely(ret))
1489 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001490 ret = aio_setup_vectored_rw(READ, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001491 if (ret)
1492 break;
1493 ret = -EINVAL;
1494 if (file->f_op->aio_read)
1495 kiocb->ki_retry = aio_rw_vect_retry;
1496 break;
1497 case IOCB_CMD_PWRITEV:
1498 ret = -EBADF;
1499 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1500 break;
1501 ret = security_file_permission(file, MAY_WRITE);
1502 if (unlikely(ret))
1503 break;
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001504 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001505 if (ret)
1506 break;
1507 ret = -EINVAL;
1508 if (file->f_op->aio_write)
1509 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 break;
1511 case IOCB_CMD_FDSYNC:
1512 ret = -EINVAL;
1513 if (file->f_op->aio_fsync)
1514 kiocb->ki_retry = aio_fdsync;
1515 break;
1516 case IOCB_CMD_FSYNC:
1517 ret = -EINVAL;
1518 if (file->f_op->aio_fsync)
1519 kiocb->ki_retry = aio_fsync;
1520 break;
1521 default:
1522 dprintk("EINVAL: io_submit: no operation provided\n");
1523 ret = -EINVAL;
1524 }
1525
1526 if (!kiocb->ki_retry)
1527 return ret;
1528
1529 return 0;
1530}
1531
Jeff Moyercfb1e332009-10-02 18:57:36 -04001532static void aio_batch_add(struct address_space *mapping,
1533 struct hlist_head *batch_hash)
1534{
1535 struct aio_batch_entry *abe;
1536 struct hlist_node *pos;
1537 unsigned bucket;
1538
1539 bucket = hash_ptr(mapping, AIO_BATCH_HASH_BITS);
1540 hlist_for_each_entry(abe, pos, &batch_hash[bucket], list) {
1541 if (abe->mapping == mapping)
1542 return;
1543 }
1544
1545 abe = mempool_alloc(abe_pool, GFP_KERNEL);
Chris Mason306fb092010-08-23 10:47:55 -04001546
1547 /*
1548 * we should be using igrab here, but
1549 * we don't want to hammer on the global
1550 * inode spinlock just to take an extra
1551 * reference on a file that we must already
1552 * have a reference to.
1553 *
1554 * When we're called, we always have a reference
1555 * on the file, so we must always have a reference
Al Viro7de9c6ee2010-10-23 11:11:40 -04001556 * on the inode, so ihold() is safe here.
Chris Mason306fb092010-08-23 10:47:55 -04001557 */
Al Viro7de9c6ee2010-10-23 11:11:40 -04001558 ihold(mapping->host);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001559 abe->mapping = mapping;
1560 hlist_add_head(&abe->list, &batch_hash[bucket]);
1561 return;
1562}
1563
1564static void aio_batch_free(struct hlist_head *batch_hash)
1565{
1566 struct aio_batch_entry *abe;
1567 struct hlist_node *pos, *n;
1568 int i;
1569
1570 for (i = 0; i < AIO_BATCH_HASH_SIZE; i++) {
1571 hlist_for_each_entry_safe(abe, pos, n, &batch_hash[i], list) {
1572 blk_run_address_space(abe->mapping);
1573 iput(abe->mapping->host);
1574 hlist_del(&abe->list);
1575 mempool_free(abe, abe_pool);
1576 }
1577 }
1578}
1579
Adrian Bunkd5470b52008-04-29 00:58:57 -07001580static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001581 struct iocb *iocb, struct hlist_head *batch_hash,
1582 bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583{
1584 struct kiocb *req;
1585 struct file *file;
1586 ssize_t ret;
1587
1588 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001589 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001590 pr_debug("EINVAL: io_submit: reserve field set\n");
1591 return -EINVAL;
1592 }
1593
1594 /* prevent overflows */
1595 if (unlikely(
1596 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1597 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1598 ((ssize_t)iocb->aio_nbytes < 0)
1599 )) {
1600 pr_debug("EINVAL: io_submit: overflow check\n");
1601 return -EINVAL;
1602 }
1603
1604 file = fget(iocb->aio_fildes);
1605 if (unlikely(!file))
1606 return -EBADF;
1607
1608 req = aio_get_req(ctx); /* returns with 2 references to req */
1609 if (unlikely(!req)) {
1610 fput(file);
1611 return -EAGAIN;
1612 }
Yan Zheng87e28312007-10-08 12:16:20 -07001613 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001614 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1615 /*
1616 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1617 * instance of the file* now. The file descriptor must be
1618 * an eventfd() fd, and will be signaled for each completed
1619 * event using the eventfd_signal() function.
1620 */
Davide Libenzi13389012009-06-30 11:41:11 -07001621 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001622 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001623 ret = PTR_ERR(req->ki_eventfd);
Davide Libenzi87c3a862009-03-18 17:04:19 -07001624 req->ki_eventfd = NULL;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001625 goto out_put_req;
1626 }
1627 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628
Ken Chen212079c2005-05-01 08:59:15 -07001629 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630 if (unlikely(ret)) {
1631 dprintk("EFAULT: aio_key\n");
1632 goto out_put_req;
1633 }
1634
1635 req->ki_obj.user = user_iocb;
1636 req->ki_user_data = iocb->aio_data;
1637 req->ki_pos = iocb->aio_offset;
1638
1639 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1640 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1641 req->ki_opcode = iocb->aio_lio_opcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001643 ret = aio_setup_iocb(req, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644
1645 if (ret)
1646 goto out_put_req;
1647
1648 spin_lock_irq(&ctx->ctx_lock);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001649 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001650 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001651 /* drain the run list */
1652 while (__aio_run_iocbs(ctx))
1653 ;
1654 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyercfb1e332009-10-02 18:57:36 -04001656 if (req->ki_opcode == IOCB_CMD_PREAD ||
1657 req->ki_opcode == IOCB_CMD_PREADV ||
1658 req->ki_opcode == IOCB_CMD_PWRITE ||
1659 req->ki_opcode == IOCB_CMD_PWRITEV)
1660 aio_batch_add(file->f_mapping, batch_hash);
1661
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 aio_put_req(req); /* drop extra ref to req */
1663 return 0;
1664
1665out_put_req:
1666 aio_put_req(req); /* drop extra ref to req */
1667 aio_put_req(req); /* drop i/o ref to req */
1668 return ret;
1669}
1670
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001671long do_io_submit(aio_context_t ctx_id, long nr,
1672 struct iocb __user *__user *iocbpp, bool compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673{
1674 struct kioctx *ctx;
1675 long ret = 0;
1676 int i;
Jeff Moyercfb1e332009-10-02 18:57:36 -04001677 struct hlist_head batch_hash[AIO_BATCH_HASH_SIZE] = { { 0, }, };
Linus Torvalds1da177e2005-04-16 15:20:36 -07001678
1679 if (unlikely(nr < 0))
1680 return -EINVAL;
1681
Jeff Moyer75e1c702010-09-10 14:16:00 -07001682 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1683 nr = LONG_MAX/sizeof(*iocbpp);
1684
Linus Torvalds1da177e2005-04-16 15:20:36 -07001685 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1686 return -EFAULT;
1687
1688 ctx = lookup_ioctx(ctx_id);
1689 if (unlikely(!ctx)) {
1690 pr_debug("EINVAL: io_submit: invalid context id\n");
1691 return -EINVAL;
1692 }
1693
1694 /*
1695 * AKPM: should this return a partial result if some of the IOs were
1696 * successfully submitted?
1697 */
1698 for (i=0; i<nr; i++) {
1699 struct iocb __user *user_iocb;
1700 struct iocb tmp;
1701
1702 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1703 ret = -EFAULT;
1704 break;
1705 }
1706
1707 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1708 ret = -EFAULT;
1709 break;
1710 }
1711
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001712 ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash, compat);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 if (ret)
1714 break;
1715 }
Jeff Moyercfb1e332009-10-02 18:57:36 -04001716 aio_batch_free(batch_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717
1718 put_ioctx(ctx);
1719 return i ? i : ret;
1720}
1721
Jeff Moyer9d85cba2010-05-26 14:44:26 -07001722/* sys_io_submit:
1723 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1724 * the number of iocbs queued. May return -EINVAL if the aio_context
1725 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1726 * *iocbpp[0] is not properly initialized, if the operation specified
1727 * is invalid for the file descriptor in the iocb. May fail with
1728 * -EFAULT if any of the data structures point to invalid data. May
1729 * fail with -EBADF if the file descriptor specified in the first
1730 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1731 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1732 * fail with -ENOSYS if not implemented.
1733 */
1734SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1735 struct iocb __user * __user *, iocbpp)
1736{
1737 return do_io_submit(ctx_id, nr, iocbpp, 0);
1738}
1739
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740/* lookup_kiocb
1741 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001743static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1744 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745{
1746 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001747
1748 assert_spin_locked(&ctx->ctx_lock);
1749
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 /* TODO: use a hash or array, this sucks. */
1751 list_for_each(pos, &ctx->active_reqs) {
1752 struct kiocb *kiocb = list_kiocb(pos);
1753 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1754 return kiocb;
1755 }
1756 return NULL;
1757}
1758
1759/* sys_io_cancel:
1760 * Attempts to cancel an iocb previously passed to io_submit. If
1761 * the operation is successfully cancelled, the resulting event is
1762 * copied into the memory pointed to by result without being placed
1763 * into the completion queue and 0 is returned. May fail with
1764 * -EFAULT if any of the data structures pointed to are invalid.
1765 * May fail with -EINVAL if aio_context specified by ctx_id is
1766 * invalid. May fail with -EAGAIN if the iocb specified was not
1767 * cancelled. Will fail with -ENOSYS if not implemented.
1768 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001769SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1770 struct io_event __user *, result)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771{
1772 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1773 struct kioctx *ctx;
1774 struct kiocb *kiocb;
1775 u32 key;
1776 int ret;
1777
1778 ret = get_user(key, &iocb->aio_key);
1779 if (unlikely(ret))
1780 return -EFAULT;
1781
1782 ctx = lookup_ioctx(ctx_id);
1783 if (unlikely(!ctx))
1784 return -EINVAL;
1785
1786 spin_lock_irq(&ctx->ctx_lock);
1787 ret = -EAGAIN;
1788 kiocb = lookup_kiocb(ctx, iocb, key);
1789 if (kiocb && kiocb->ki_cancel) {
1790 cancel = kiocb->ki_cancel;
1791 kiocb->ki_users ++;
1792 kiocbSetCancelled(kiocb);
1793 } else
1794 cancel = NULL;
1795 spin_unlock_irq(&ctx->ctx_lock);
1796
1797 if (NULL != cancel) {
1798 struct io_event tmp;
1799 pr_debug("calling cancel\n");
1800 memset(&tmp, 0, sizeof(tmp));
1801 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1802 tmp.data = kiocb->ki_user_data;
1803 ret = cancel(kiocb, &tmp);
1804 if (!ret) {
1805 /* Cancellation succeeded -- copy the result
1806 * into the user's buffer.
1807 */
1808 if (copy_to_user(result, &tmp, sizeof(tmp)))
1809 ret = -EFAULT;
1810 }
1811 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001812 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813
1814 put_ioctx(ctx);
1815
1816 return ret;
1817}
1818
1819/* io_getevents:
1820 * Attempts to read at least min_nr events and up to nr events from
Satoru Takeuchi642b5122010-08-05 11:23:11 -07001821 * the completion queue for the aio_context specified by ctx_id. If
1822 * it succeeds, the number of read events is returned. May fail with
1823 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1824 * out of range, if timeout is out of range. May fail with -EFAULT
1825 * if any of the memory specified is invalid. May return 0 or
1826 * < min_nr if the timeout specified by timeout has elapsed
1827 * before sufficient events are available, where timeout == NULL
1828 * specifies an infinite timeout. Note that the timeout pointed to by
1829 * timeout is relative and will be updated if not NULL and the
1830 * operation blocks. Will fail with -ENOSYS if not implemented.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001832SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1833 long, min_nr,
1834 long, nr,
1835 struct io_event __user *, events,
1836 struct timespec __user *, timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837{
1838 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1839 long ret = -EINVAL;
1840
1841 if (likely(ioctx)) {
1842 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1843 ret = read_events(ioctx, min_nr, nr, events, timeout);
1844 put_ioctx(ioctx);
1845 }
1846
Roland McGrath598af052008-04-10 15:38:45 -07001847 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848 return ret;
1849}