blob: b74c567383bc3689412a6195cb5fd4e2520cb724 [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>
Badari Pulavarty027445c2006-09-30 23:28:46 -070018#include <linux/uio.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20#define DEBUG 0
21
22#include <linux/sched.h>
23#include <linux/fs.h>
24#include <linux/file.h>
25#include <linux/mm.h>
26#include <linux/mman.h>
27#include <linux/slab.h>
28#include <linux/timer.h>
29#include <linux/aio.h>
30#include <linux/highmem.h>
31#include <linux/workqueue.h>
32#include <linux/security.h>
Davide Libenzi9c3060b2007-05-10 22:23:21 -070033#include <linux/eventfd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35#include <asm/kmap_types.h>
36#include <asm/uaccess.h>
37#include <asm/mmu_context.h>
38
39#if DEBUG > 1
40#define dprintk printk
41#else
42#define dprintk(x...) do { ; } while (0)
43#endif
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045/*------ sysctl variables----*/
Zach Brownd55b5fd2005-11-07 00:59:31 -080046static DEFINE_SPINLOCK(aio_nr_lock);
47unsigned long aio_nr; /* current system wide number of aio requests */
48unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/*----end sysctl variables---*/
50
Christoph Lametere18b8902006-12-06 20:33:20 -080051static struct kmem_cache *kiocb_cachep;
52static struct kmem_cache *kioctx_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54static struct workqueue_struct *aio_wq;
55
56/* Used for rare fput completion. */
David Howells65f27f32006-11-22 14:55:48 +000057static void aio_fput_routine(struct work_struct *);
58static DECLARE_WORK(fput_work, aio_fput_routine);
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60static DEFINE_SPINLOCK(fput_lock);
Adrian Bunk25ee7e32005-04-25 08:18:14 -070061static LIST_HEAD(fput_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
David Howells65f27f32006-11-22 14:55:48 +000063static void aio_kick_handler(struct work_struct *);
Sébastien Duguc016e222005-06-28 20:44:59 -070064static void aio_queue_work(struct kioctx *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66/* aio_setup
67 * Creates the slab caches used by the aio routines, panic on
68 * failure as this is done early during the boot sequence.
69 */
70static int __init aio_setup(void)
71{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070072 kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
73 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75 aio_wq = create_workqueue("aio");
76
77 pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
78
79 return 0;
80}
81
82static void aio_free_ring(struct kioctx *ctx)
83{
84 struct aio_ring_info *info = &ctx->ring_info;
85 long i;
86
87 for (i=0; i<info->nr_pages; i++)
88 put_page(info->ring_pages[i]);
89
90 if (info->mmap_size) {
91 down_write(&ctx->mm->mmap_sem);
92 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
93 up_write(&ctx->mm->mmap_sem);
94 }
95
96 if (info->ring_pages && info->ring_pages != info->internal_pages)
97 kfree(info->ring_pages);
98 info->ring_pages = NULL;
99 info->nr = 0;
100}
101
102static int aio_setup_ring(struct kioctx *ctx)
103{
104 struct aio_ring *ring;
105 struct aio_ring_info *info = &ctx->ring_info;
106 unsigned nr_events = ctx->max_reqs;
107 unsigned long size;
108 int nr_pages;
109
110 /* Compensate for the ring buffer's head/tail overlap entry */
111 nr_events += 2; /* 1 is required, 2 for good luck */
112
113 size = sizeof(struct aio_ring);
114 size += sizeof(struct io_event) * nr_events;
115 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
116
117 if (nr_pages < 0)
118 return -EINVAL;
119
120 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
121
122 info->nr = 0;
123 info->ring_pages = info->internal_pages;
124 if (nr_pages > AIO_RING_PAGES) {
Oliver Neukum11b0b5a2006-03-25 03:08:13 -0800125 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 if (!info->ring_pages)
127 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 }
129
130 info->mmap_size = nr_pages * PAGE_SIZE;
131 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
132 down_write(&ctx->mm->mmap_sem);
133 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
Robert P. J. Daye10a4432007-02-10 01:42:56 -0800134 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 0);
136 if (IS_ERR((void *)info->mmap_base)) {
137 up_write(&ctx->mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 info->mmap_size = 0;
139 aio_free_ring(ctx);
140 return -EAGAIN;
141 }
142
143 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
144 info->nr_pages = get_user_pages(current, ctx->mm,
145 info->mmap_base, nr_pages,
146 1, 0, info->ring_pages, NULL);
147 up_write(&ctx->mm->mmap_sem);
148
149 if (unlikely(info->nr_pages != nr_pages)) {
150 aio_free_ring(ctx);
151 return -EAGAIN;
152 }
153
154 ctx->user_id = info->mmap_base;
155
156 info->nr = nr_events; /* trusted copy */
157
158 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
159 ring->nr = nr_events; /* user copy */
160 ring->id = ctx->user_id;
161 ring->head = ring->tail = 0;
162 ring->magic = AIO_RING_MAGIC;
163 ring->compat_features = AIO_RING_COMPAT_FEATURES;
164 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
165 ring->header_length = sizeof(struct aio_ring);
166 kunmap_atomic(ring, KM_USER0);
167
168 return 0;
169}
170
171
172/* aio_ring_event: returns a pointer to the event at the given index from
173 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
174 */
175#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
176#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
177#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
178
179#define aio_ring_event(info, nr, km) ({ \
180 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
181 struct io_event *__event; \
182 __event = kmap_atomic( \
183 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
184 __event += pos % AIO_EVENTS_PER_PAGE; \
185 __event; \
186})
187
188#define put_aio_ring_event(event, km) do { \
189 struct io_event *__event = (event); \
190 (void)__event; \
191 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
192} while(0)
193
194/* ioctx_alloc
195 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
196 */
197static struct kioctx *ioctx_alloc(unsigned nr_events)
198{
199 struct mm_struct *mm;
200 struct kioctx *ctx;
201
202 /* Prevent overflows */
203 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
204 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
205 pr_debug("ENOMEM: nr_events too high\n");
206 return ERR_PTR(-EINVAL);
207 }
208
Zach Brownd55b5fd2005-11-07 00:59:31 -0800209 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 return ERR_PTR(-EAGAIN);
211
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800212 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 if (!ctx)
214 return ERR_PTR(-ENOMEM);
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 ctx->max_reqs = nr_events;
217 mm = ctx->mm = current->mm;
218 atomic_inc(&mm->mm_count);
219
220 atomic_set(&ctx->users, 1);
221 spin_lock_init(&ctx->ctx_lock);
222 spin_lock_init(&ctx->ring_info.ring_lock);
223 init_waitqueue_head(&ctx->wait);
224
225 INIT_LIST_HEAD(&ctx->active_reqs);
226 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000227 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
229 if (aio_setup_ring(ctx) < 0)
230 goto out_freectx;
231
232 /* limit the number of system wide aios */
Zach Brownd55b5fd2005-11-07 00:59:31 -0800233 spin_lock(&aio_nr_lock);
234 if (aio_nr + ctx->max_reqs > aio_max_nr ||
235 aio_nr + ctx->max_reqs < aio_nr)
236 ctx->max_reqs = 0;
237 else
238 aio_nr += ctx->max_reqs;
239 spin_unlock(&aio_nr_lock);
240 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 goto out_cleanup;
242
243 /* now link into global list. kludge. FIXME */
244 write_lock(&mm->ioctx_list_lock);
245 ctx->next = mm->ioctx_list;
246 mm->ioctx_list = ctx;
247 write_unlock(&mm->ioctx_list_lock);
248
249 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
250 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
251 return ctx;
252
253out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 __put_ioctx(ctx);
255 return ERR_PTR(-EAGAIN);
256
257out_freectx:
258 mmdrop(mm);
259 kmem_cache_free(kioctx_cachep, ctx);
260 ctx = ERR_PTR(-ENOMEM);
261
262 dprintk("aio: error allocating ioctx %p\n", ctx);
263 return ctx;
264}
265
266/* aio_cancel_all
267 * Cancels all outstanding aio requests on an aio context. Used
268 * when the processes owning a context have all exited to encourage
269 * the rapid destruction of the kioctx.
270 */
271static void aio_cancel_all(struct kioctx *ctx)
272{
273 int (*cancel)(struct kiocb *, struct io_event *);
274 struct io_event res;
275 spin_lock_irq(&ctx->ctx_lock);
276 ctx->dead = 1;
277 while (!list_empty(&ctx->active_reqs)) {
278 struct list_head *pos = ctx->active_reqs.next;
279 struct kiocb *iocb = list_kiocb(pos);
280 list_del_init(&iocb->ki_list);
281 cancel = iocb->ki_cancel;
282 kiocbSetCancelled(iocb);
283 if (cancel) {
284 iocb->ki_users++;
285 spin_unlock_irq(&ctx->ctx_lock);
286 cancel(iocb, &res);
287 spin_lock_irq(&ctx->ctx_lock);
288 }
289 }
290 spin_unlock_irq(&ctx->ctx_lock);
291}
292
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700293static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294{
295 struct task_struct *tsk = current;
296 DECLARE_WAITQUEUE(wait, tsk);
297
Ken Chendee11c22007-02-03 01:13:45 -0800298 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800300 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
302 add_wait_queue(&ctx->wait, &wait);
303 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
304 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800305 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700306 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800308 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 }
310 __set_task_state(tsk, TASK_RUNNING);
311 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800312
313out:
314 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315}
316
317/* wait_on_sync_kiocb:
318 * Waits on the given sync kiocb to complete.
319 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800320ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321{
322 while (iocb->ki_users) {
323 set_current_state(TASK_UNINTERRUPTIBLE);
324 if (!iocb->ki_users)
325 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700326 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 }
328 __set_current_state(TASK_RUNNING);
329 return iocb->ki_user_data;
330}
331
332/* exit_aio: called when the last user of mm goes away. At this point,
333 * there is no way for any new requests to be submited or any of the
334 * io_* syscalls to be called on the context. However, there may be
335 * outstanding requests which hold references to the context; as they
336 * go away, they will call put_ioctx and release any pinned memory
337 * associated with the request (held via struct page * references).
338 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800339void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
341 struct kioctx *ctx = mm->ioctx_list;
342 mm->ioctx_list = NULL;
343 while (ctx) {
344 struct kioctx *next = ctx->next;
345 ctx->next = NULL;
346 aio_cancel_all(ctx);
347
348 wait_for_all_aios(ctx);
349 /*
Andrew Mortona9df62c2007-05-09 02:33:54 -0700350 * Ensure we don't leave the ctx on the aio_wq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 */
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700352 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353
354 if (1 != atomic_read(&ctx->users))
355 printk(KERN_DEBUG
356 "exit_aio:ioctx still alive: %d %d %d\n",
357 atomic_read(&ctx->users), ctx->dead,
358 ctx->reqs_active);
359 put_ioctx(ctx);
360 ctx = next;
361 }
362}
363
364/* __put_ioctx
365 * Called when the last user of an aio context has gone away,
366 * and the struct needs to be freed.
367 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800368void __put_ioctx(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369{
370 unsigned nr_events = ctx->max_reqs;
371
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100372 BUG_ON(ctx->reqs_active);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373
374 cancel_delayed_work(&ctx->wq);
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700375 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 aio_free_ring(ctx);
377 mmdrop(ctx->mm);
378 ctx->mm = NULL;
379 pr_debug("__put_ioctx: freeing %p\n", ctx);
380 kmem_cache_free(kioctx_cachep, ctx);
381
Zach Brownd55b5fd2005-11-07 00:59:31 -0800382 if (nr_events) {
383 spin_lock(&aio_nr_lock);
384 BUG_ON(aio_nr - nr_events > aio_nr);
385 aio_nr -= nr_events;
386 spin_unlock(&aio_nr_lock);
387 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388}
389
390/* aio_get_req
391 * Allocate a slot for an aio request. Increments the users count
392 * of the kioctx so that the kioctx stays around until all requests are
393 * complete. Returns NULL if no requests are free.
394 *
395 * Returns with kiocb->users set to 2. The io submit code path holds
396 * an extra reference while submitting the i/o.
397 * This prevents races between the aio code path referencing the
398 * req (after submitting it) and aio_complete() freeing the req.
399 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800400static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401{
402 struct kiocb *req = NULL;
403 struct aio_ring *ring;
404 int okay = 0;
405
406 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
407 if (unlikely(!req))
408 return NULL;
409
Zach Brown4faa5282005-10-17 16:43:33 -0700410 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 req->ki_users = 2;
412 req->ki_key = 0;
413 req->ki_ctx = ctx;
414 req->ki_cancel = NULL;
415 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 req->ki_dtor = NULL;
417 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700418 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi9c3060b2007-05-10 22:23:21 -0700420 req->ki_eventfd = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
422 /* Check if the completion queue has enough free space to
423 * accept an event from this io.
424 */
425 spin_lock_irq(&ctx->ctx_lock);
426 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
427 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
428 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 ctx->reqs_active++;
430 okay = 1;
431 }
432 kunmap_atomic(ring, KM_USER0);
433 spin_unlock_irq(&ctx->ctx_lock);
434
435 if (!okay) {
436 kmem_cache_free(kiocb_cachep, req);
437 req = NULL;
438 }
439
440 return req;
441}
442
443static inline struct kiocb *aio_get_req(struct kioctx *ctx)
444{
445 struct kiocb *req;
446 /* Handle a potential starvation case -- should be exceedingly rare as
447 * requests will be stuck on fput_head only if the aio_fput_routine is
448 * delayed and the requests were the last user of the struct file.
449 */
450 req = __aio_get_req(ctx);
451 if (unlikely(NULL == req)) {
452 aio_fput_routine(NULL);
453 req = __aio_get_req(ctx);
454 }
455 return req;
456}
457
458static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
459{
Zach Brownd00689a2005-11-13 16:07:34 -0800460 assert_spin_locked(&ctx->ctx_lock);
461
Davide Libenzi9c3060b2007-05-10 22:23:21 -0700462 if (!IS_ERR(req->ki_eventfd))
463 fput(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 if (req->ki_dtor)
465 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700466 if (req->ki_iovec != &req->ki_inline_vec)
467 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 kmem_cache_free(kiocb_cachep, req);
469 ctx->reqs_active--;
470
471 if (unlikely(!ctx->reqs_active && ctx->dead))
472 wake_up(&ctx->wait);
473}
474
David Howells65f27f32006-11-22 14:55:48 +0000475static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476{
477 spin_lock_irq(&fput_lock);
478 while (likely(!list_empty(&fput_head))) {
479 struct kiocb *req = list_kiocb(fput_head.next);
480 struct kioctx *ctx = req->ki_ctx;
481
482 list_del(&req->ki_list);
483 spin_unlock_irq(&fput_lock);
484
485 /* Complete the fput */
486 __fput(req->ki_filp);
487
488 /* Link the iocb into the context's free list */
489 spin_lock_irq(&ctx->ctx_lock);
490 really_put_req(ctx, req);
491 spin_unlock_irq(&ctx->ctx_lock);
492
493 put_ioctx(ctx);
494 spin_lock_irq(&fput_lock);
495 }
496 spin_unlock_irq(&fput_lock);
497}
498
499/* __aio_put_req
500 * Returns true if this put was the last user of the request.
501 */
502static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
503{
504 dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
505 req, atomic_read(&req->ki_filp->f_count));
506
Zach Brownd00689a2005-11-13 16:07:34 -0800507 assert_spin_locked(&ctx->ctx_lock);
508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 req->ki_users --;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100510 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (likely(req->ki_users))
512 return 0;
513 list_del(&req->ki_list); /* remove from active_reqs */
514 req->ki_cancel = NULL;
515 req->ki_retry = NULL;
516
517 /* Must be done under the lock to serialise against cancellation.
518 * Call this aio_fput as it duplicates fput via the fput_work.
519 */
Nick Piggin095975d2006-01-08 01:02:19 -0800520 if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 get_ioctx(ctx);
522 spin_lock(&fput_lock);
523 list_add(&req->ki_list, &fput_head);
524 spin_unlock(&fput_lock);
525 queue_work(aio_wq, &fput_work);
526 } else
527 really_put_req(ctx, req);
528 return 1;
529}
530
531/* aio_put_req
532 * Returns true if this put was the last user of the kiocb,
533 * false if the request is still in use.
534 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800535int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536{
537 struct kioctx *ctx = req->ki_ctx;
538 int ret;
539 spin_lock_irq(&ctx->ctx_lock);
540 ret = __aio_put_req(ctx, req);
541 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 return ret;
543}
544
545/* Lookup an ioctx id. ioctx_list is lockless for reads.
546 * FIXME: this is O(n) and is only suitable for development.
547 */
548struct kioctx *lookup_ioctx(unsigned long ctx_id)
549{
550 struct kioctx *ioctx;
551 struct mm_struct *mm;
552
553 mm = current->mm;
554 read_lock(&mm->ioctx_list_lock);
555 for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next)
556 if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) {
557 get_ioctx(ioctx);
558 break;
559 }
560 read_unlock(&mm->ioctx_list_lock);
561
562 return ioctx;
563}
564
565/*
566 * use_mm
567 * Makes the calling kernel thread take on the specified
568 * mm context.
569 * Called by the retry thread execute retries within the
570 * iocb issuer's mm context, so that copy_from/to_user
571 * operations work seamlessly for aio.
572 * (Note: this routine is intended to be called only
573 * from a kernel thread context)
574 */
575static void use_mm(struct mm_struct *mm)
576{
577 struct mm_struct *active_mm;
578 struct task_struct *tsk = current;
579
580 task_lock(tsk);
581 tsk->flags |= PF_BORROWED_MM;
582 active_mm = tsk->active_mm;
583 atomic_inc(&mm->mm_count);
584 tsk->mm = mm;
585 tsk->active_mm = mm;
Paolo 'Blaisorblade' Giarrusso1e40cd32005-09-03 15:57:25 -0700586 /*
587 * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
588 * it won't work. Update it accordingly if you change it here
589 */
Jeremy Fitzhardinge90aef122006-12-13 00:34:49 -0800590 switch_mm(active_mm, mm, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 task_unlock(tsk);
592
593 mmdrop(active_mm);
594}
595
596/*
597 * unuse_mm
598 * Reverses the effect of use_mm, i.e. releases the
599 * specified mm context which was earlier taken on
600 * by the calling kernel thread
601 * (Note: this routine is intended to be called only
602 * from a kernel thread context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700604static void unuse_mm(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605{
606 struct task_struct *tsk = current;
607
608 task_lock(tsk);
609 tsk->flags &= ~PF_BORROWED_MM;
610 tsk->mm = NULL;
611 /* active_mm is still 'mm' */
612 enter_lazy_tlb(mm, tsk);
613 task_unlock(tsk);
614}
615
616/*
617 * Queue up a kiocb to be retried. Assumes that the kiocb
618 * has already been marked as kicked, and places it on
619 * the retry run list for the corresponding ioctx, if it
620 * isn't already queued. Returns 1 if it actually queued
621 * the kiocb (to tell the caller to activate the work
622 * queue to process it), or 0, if it found that it was
623 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 */
625static inline int __queue_kicked_iocb(struct kiocb *iocb)
626{
627 struct kioctx *ctx = iocb->ki_ctx;
628
Zach Brownd00689a2005-11-13 16:07:34 -0800629 assert_spin_locked(&ctx->ctx_lock);
630
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 if (list_empty(&iocb->ki_run_list)) {
632 list_add_tail(&iocb->ki_run_list,
633 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 return 1;
635 }
636 return 0;
637}
638
639/* aio_run_iocb
640 * This is the core aio execution routine. It is
641 * invoked both for initial i/o submission and
642 * subsequent retries via the aio_kick_handler.
643 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200644 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 * as needed during processing.
646 *
647 * Calls the iocb retry method (already setup for the
648 * iocb on initial submission) for operation specific
649 * handling, but takes care of most of common retry
650 * execution details for a given iocb. The retry method
651 * needs to be non-blocking as far as possible, to avoid
652 * holding up other iocbs waiting to be serviced by the
653 * retry kernel thread.
654 *
655 * The trickier parts in this code have to do with
656 * ensuring that only one retry instance is in progress
657 * for a given iocb at any time. Providing that guarantee
658 * simplifies the coding of individual aio operations as
659 * it avoids various potential races.
660 */
661static ssize_t aio_run_iocb(struct kiocb *iocb)
662{
663 struct kioctx *ctx = iocb->ki_ctx;
664 ssize_t (*retry)(struct kiocb *);
665 ssize_t ret;
666
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 if (!(retry = iocb->ki_retry)) {
668 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
669 return 0;
670 }
671
672 /*
673 * We don't want the next retry iteration for this
674 * operation to start until this one has returned and
675 * updated the iocb state. However, wait_queue functions
676 * can trigger a kick_iocb from interrupt context in the
677 * meantime, indicating that data is available for the next
678 * iteration. We want to remember that and enable the
679 * next retry iteration _after_ we are through with
680 * this one.
681 *
682 * So, in order to be able to register a "kick", but
683 * prevent it from being queued now, we clear the kick
684 * flag, but make the kick code *think* that the iocb is
685 * still on the run list until we are actually done.
686 * When we are done with this iteration, we check if
687 * the iocb was kicked in the meantime and if so, queue
688 * it up afresh.
689 */
690
691 kiocbClearKicked(iocb);
692
693 /*
694 * This is so that aio_complete knows it doesn't need to
695 * pull the iocb off the run list (We can't just call
696 * INIT_LIST_HEAD because we don't want a kick_iocb to
697 * queue this on the run list yet)
698 */
699 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
700 spin_unlock_irq(&ctx->ctx_lock);
701
702 /* Quit retrying if the i/o has been cancelled */
703 if (kiocbIsCancelled(iocb)) {
704 ret = -EINTR;
705 aio_complete(iocb, ret, 0);
706 /* must not access the iocb after this */
707 goto out;
708 }
709
710 /*
711 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700712 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
Zach Brown897f15f2005-09-30 11:58:55 -0700716 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
717 BUG_ON(!list_empty(&iocb->ki_wait.task_list));
718 aio_complete(iocb, ret, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 }
720out:
721 spin_lock_irq(&ctx->ctx_lock);
722
723 if (-EIOCBRETRY == ret) {
724 /*
725 * OK, now that we are done with this iteration
726 * and know that there is more left to go,
727 * this is where we let go so that a subsequent
728 * "kick" can start the next iteration
729 */
730
731 /* will make __queue_kicked_iocb succeed from here on */
732 INIT_LIST_HEAD(&iocb->ki_run_list);
733 /* we must queue the next iteration ourselves, if it
734 * has already been kicked */
735 if (kiocbIsKicked(iocb)) {
736 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700737
738 /*
739 * __queue_kicked_iocb will always return 1 here, because
740 * iocb->ki_run_list is empty at this point so it should
741 * be safe to unconditionally queue the context into the
742 * work queue.
743 */
744 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 }
746 }
747 return ret;
748}
749
750/*
751 * __aio_run_iocbs:
752 * Process all pending retries queued on the ioctx
753 * run list.
754 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800755 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 */
757static int __aio_run_iocbs(struct kioctx *ctx)
758{
759 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700760 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761
Zach Brownd00689a2005-11-13 16:07:34 -0800762 assert_spin_locked(&ctx->ctx_lock);
763
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700764 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 while (!list_empty(&run_list)) {
766 iocb = list_entry(run_list.next, struct kiocb,
767 ki_run_list);
768 list_del(&iocb->ki_run_list);
769 /*
770 * Hold an extra reference while retrying i/o.
771 */
772 iocb->ki_users++; /* grab extra reference */
773 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800774 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 if (!list_empty(&ctx->run_list))
777 return 1;
778 return 0;
779}
780
781static void aio_queue_work(struct kioctx * ctx)
782{
783 unsigned long timeout;
784 /*
785 * if someone is waiting, get the work started right
786 * away, otherwise, use a longer delay
787 */
788 smp_mb();
789 if (waitqueue_active(&ctx->wait))
790 timeout = 1;
791 else
792 timeout = HZ/10;
793 queue_delayed_work(aio_wq, &ctx->wq, timeout);
794}
795
796
797/*
798 * aio_run_iocbs:
799 * Process all pending retries queued on the ioctx
800 * run list.
801 * Assumes it is operating within the aio issuer's mm
802 * context.
803 */
804static inline void aio_run_iocbs(struct kioctx *ctx)
805{
806 int requeue;
807
808 spin_lock_irq(&ctx->ctx_lock);
809
810 requeue = __aio_run_iocbs(ctx);
811 spin_unlock_irq(&ctx->ctx_lock);
812 if (requeue)
813 aio_queue_work(ctx);
814}
815
816/*
817 * just like aio_run_iocbs, but keeps running them until
818 * the list stays empty
819 */
820static inline void aio_run_all_iocbs(struct kioctx *ctx)
821{
822 spin_lock_irq(&ctx->ctx_lock);
823 while (__aio_run_iocbs(ctx))
824 ;
825 spin_unlock_irq(&ctx->ctx_lock);
826}
827
828/*
829 * aio_kick_handler:
830 * Work queue handler triggered to process pending
831 * retries on an ioctx. Takes on the aio issuer's
832 * mm context before running the iocbs, so that
833 * copy_xxx_user operates on the issuer's address
834 * space.
835 * Run on aiod's context.
836 */
David Howells65f27f32006-11-22 14:55:48 +0000837static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838{
David Howells65f27f32006-11-22 14:55:48 +0000839 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800841 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 int requeue;
843
844 set_fs(USER_DS);
845 use_mm(ctx->mm);
846 spin_lock_irq(&ctx->ctx_lock);
847 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800848 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800850 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 set_fs(oldfs);
852 /*
853 * we're in a worker thread already, don't use queue_delayed_work,
854 */
855 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000856 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857}
858
859
860/*
861 * Called by kick_iocb to queue the kiocb for retry
862 * and if required activate the aio work queue to process
863 * it
864 */
Zach Brown998765e2005-09-30 11:58:54 -0700865static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866{
867 struct kioctx *ctx = iocb->ki_ctx;
868 unsigned long flags;
869 int run = 0;
870
Zach Brown998765e2005-09-30 11:58:54 -0700871 /* We're supposed to be the only path putting the iocb back on the run
872 * list. If we find that the iocb is *back* on a wait queue already
873 * than retry has happened before we could queue the iocb. This also
874 * means that the retry could have completed and freed our iocb, no
875 * good. */
876 BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877
878 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700879 /* set this inside the lock so that we can't race with aio_run_iocb()
880 * testing it and putting the iocb on the run list under the lock */
881 if (!kiocbTryKick(iocb))
882 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700884 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886}
887
888/*
889 * kick_iocb:
890 * Called typically from a wait queue callback context
891 * (aio_wake_function) to trigger a retry of the iocb.
892 * The retry is usually executed by aio workqueue
893 * threads (See aio_kick_handler).
894 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800895void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896{
897 /* sync iocbs are easy: they can only ever be executing from a
898 * single context. */
899 if (is_sync_kiocb(iocb)) {
900 kiocbSetKicked(iocb);
901 wake_up_process(iocb->ki_obj.tsk);
902 return;
903 }
904
Zach Brown998765e2005-09-30 11:58:54 -0700905 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906}
907EXPORT_SYMBOL(kick_iocb);
908
909/* aio_complete
910 * Called when the io request on the given iocb is complete.
911 * Returns true if this is the last user of the request. The
912 * only other user of the request can be the cancellation code.
913 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800914int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915{
916 struct kioctx *ctx = iocb->ki_ctx;
917 struct aio_ring_info *info;
918 struct aio_ring *ring;
919 struct io_event *event;
920 unsigned long flags;
921 unsigned long tail;
922 int ret;
923
Zach Brown20dcae32005-11-13 16:07:33 -0800924 /*
925 * Special case handling for sync iocbs:
926 * - events go directly into the iocb for fast handling
927 * - the sync task with the iocb in its stack holds the single iocb
928 * ref, no other paths have a way to get another ref
929 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 */
931 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800932 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800934 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800936 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 }
938
Davide Libenzi9c3060b2007-05-10 22:23:21 -0700939 /*
940 * Check if the user asked us to deliver the result through an
941 * eventfd. The eventfd_signal() function is safe to be called
942 * from IRQ context.
943 */
944 if (!IS_ERR(iocb->ki_eventfd))
945 eventfd_signal(iocb->ki_eventfd, 1);
946
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 info = &ctx->ring_info;
948
949 /* add a completion event to the ring buffer.
950 * must be done holding ctx->ctx_lock to prevent
951 * other code from messing with the tail
952 * pointer since we might be called from irq
953 * context.
954 */
955 spin_lock_irqsave(&ctx->ctx_lock, flags);
956
957 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
958 list_del_init(&iocb->ki_run_list);
959
960 /*
961 * cancelled requests don't get events, userland was given one
962 * when the event got cancelled.
963 */
964 if (kiocbIsCancelled(iocb))
965 goto put_rq;
966
967 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
968
969 tail = info->tail;
970 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700971 if (++tail >= info->nr)
972 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
974 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
975 event->data = iocb->ki_user_data;
976 event->res = res;
977 event->res2 = res2;
978
979 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
980 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
981 res, res2);
982
983 /* after flagging the request as done, we
984 * must never even look at it again
985 */
986 smp_wmb(); /* make event visible before updating tail */
987
988 info->tail = tail;
989 ring->tail = tail;
990
991 put_aio_ring_event(event, KM_IRQ0);
992 kunmap_atomic(ring, KM_IRQ1);
993
994 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995put_rq:
996 /* everything turned out well, dispose of the aiocb. */
997 ret = __aio_put_req(ctx, iocb);
998
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 if (waitqueue_active(&ctx->wait))
1000 wake_up(&ctx->wait);
1001
Ken Chendee11c22007-02-03 01:13:45 -08001002 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 return ret;
1004}
1005
1006/* aio_read_evt
1007 * Pull an event off of the ioctx's event ring. Returns the number of
1008 * events fetched (0 or 1 ;-)
1009 * FIXME: make this use cmpxchg.
1010 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1011 */
1012static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1013{
1014 struct aio_ring_info *info = &ioctx->ring_info;
1015 struct aio_ring *ring;
1016 unsigned long head;
1017 int ret = 0;
1018
1019 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1020 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1021 (unsigned long)ring->head, (unsigned long)ring->tail,
1022 (unsigned long)ring->nr);
1023
1024 if (ring->head == ring->tail)
1025 goto out;
1026
1027 spin_lock(&info->ring_lock);
1028
1029 head = ring->head % info->nr;
1030 if (head != ring->tail) {
1031 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1032 *ent = *evp;
1033 head = (head + 1) % info->nr;
1034 smp_mb(); /* finish reading the event before updatng the head */
1035 ring->head = head;
1036 ret = 1;
1037 put_aio_ring_event(evp, KM_USER1);
1038 }
1039 spin_unlock(&info->ring_lock);
1040
1041out:
1042 kunmap_atomic(ring, KM_USER0);
1043 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1044 (unsigned long)ring->head, (unsigned long)ring->tail);
1045 return ret;
1046}
1047
1048struct aio_timeout {
1049 struct timer_list timer;
1050 int timed_out;
1051 struct task_struct *p;
1052};
1053
1054static void timeout_func(unsigned long data)
1055{
1056 struct aio_timeout *to = (struct aio_timeout *)data;
1057
1058 to->timed_out = 1;
1059 wake_up_process(to->p);
1060}
1061
1062static inline void init_timeout(struct aio_timeout *to)
1063{
1064 init_timer(&to->timer);
1065 to->timer.data = (unsigned long)to;
1066 to->timer.function = timeout_func;
1067 to->timed_out = 0;
1068 to->p = current;
1069}
1070
1071static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1072 const struct timespec *ts)
1073{
1074 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1075 if (time_after(to->timer.expires, jiffies))
1076 add_timer(&to->timer);
1077 else
1078 to->timed_out = 1;
1079}
1080
1081static inline void clear_timeout(struct aio_timeout *to)
1082{
1083 del_singleshot_timer_sync(&to->timer);
1084}
1085
1086static int read_events(struct kioctx *ctx,
1087 long min_nr, long nr,
1088 struct io_event __user *event,
1089 struct timespec __user *timeout)
1090{
1091 long start_jiffies = jiffies;
1092 struct task_struct *tsk = current;
1093 DECLARE_WAITQUEUE(wait, tsk);
1094 int ret;
1095 int i = 0;
1096 struct io_event ent;
1097 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 int retry = 0;
1099
1100 /* needed to zero any padding within an entry (there shouldn't be
1101 * any, but C is fun!
1102 */
1103 memset(&ent, 0, sizeof(ent));
1104retry:
1105 ret = 0;
1106 while (likely(i < nr)) {
1107 ret = aio_read_evt(ctx, &ent);
1108 if (unlikely(ret <= 0))
1109 break;
1110
1111 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1112 ent.data, ent.obj, ent.res, ent.res2);
1113
1114 /* Could we split the check in two? */
1115 ret = -EFAULT;
1116 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1117 dprintk("aio: lost an event due to EFAULT.\n");
1118 break;
1119 }
1120 ret = 0;
1121
1122 /* Good, event copied to userland, update counts. */
1123 event ++;
1124 i ++;
1125 }
1126
1127 if (min_nr <= i)
1128 return i;
1129 if (ret)
1130 return ret;
1131
1132 /* End fast path */
1133
1134 /* racey check, but it gets redone */
1135 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1136 retry = 1;
1137 aio_run_all_iocbs(ctx);
1138 goto retry;
1139 }
1140
1141 init_timeout(&to);
1142 if (timeout) {
1143 struct timespec ts;
1144 ret = -EFAULT;
1145 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1146 goto out;
1147
1148 set_timeout(start_jiffies, &to, &ts);
1149 }
1150
1151 while (likely(i < nr)) {
1152 add_wait_queue_exclusive(&ctx->wait, &wait);
1153 do {
1154 set_task_state(tsk, TASK_INTERRUPTIBLE);
1155 ret = aio_read_evt(ctx, &ent);
1156 if (ret)
1157 break;
1158 if (min_nr <= i)
1159 break;
1160 ret = 0;
1161 if (to.timed_out) /* Only check after read evt */
1162 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001163 /* Try to only show up in io wait if there are ops
1164 * in flight */
1165 if (ctx->reqs_active)
1166 io_schedule();
1167 else
1168 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 if (signal_pending(tsk)) {
1170 ret = -EINTR;
1171 break;
1172 }
1173 /*ret = aio_read_evt(ctx, &ent);*/
1174 } while (1) ;
1175
1176 set_task_state(tsk, TASK_RUNNING);
1177 remove_wait_queue(&ctx->wait, &wait);
1178
1179 if (unlikely(ret <= 0))
1180 break;
1181
1182 ret = -EFAULT;
1183 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1184 dprintk("aio: lost an event due to EFAULT.\n");
1185 break;
1186 }
1187
1188 /* Good, event copied to userland, update counts. */
1189 event ++;
1190 i ++;
1191 }
1192
1193 if (timeout)
1194 clear_timeout(&to);
1195out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 return i ? i : ret;
1197}
1198
1199/* Take an ioctx and remove it from the list of ioctx's. Protects
1200 * against races with itself via ->dead.
1201 */
1202static void io_destroy(struct kioctx *ioctx)
1203{
1204 struct mm_struct *mm = current->mm;
1205 struct kioctx **tmp;
1206 int was_dead;
1207
1208 /* delete the entry from the list is someone else hasn't already */
1209 write_lock(&mm->ioctx_list_lock);
1210 was_dead = ioctx->dead;
1211 ioctx->dead = 1;
1212 for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx;
1213 tmp = &(*tmp)->next)
1214 ;
1215 if (*tmp)
1216 *tmp = ioctx->next;
1217 write_unlock(&mm->ioctx_list_lock);
1218
1219 dprintk("aio_release(%p)\n", ioctx);
1220 if (likely(!was_dead))
1221 put_ioctx(ioctx); /* twice for the list */
1222
1223 aio_cancel_all(ioctx);
1224 wait_for_all_aios(ioctx);
1225 put_ioctx(ioctx); /* once for the lookup */
1226}
1227
1228/* sys_io_setup:
1229 * Create an aio_context capable of receiving at least nr_events.
1230 * ctxp must not point to an aio_context that already exists, and
1231 * must be initialized to 0 prior to the call. On successful
1232 * creation of the aio_context, *ctxp is filled in with the resulting
1233 * handle. May fail with -EINVAL if *ctxp is not initialized,
1234 * if the specified nr_events exceeds internal limits. May fail
1235 * with -EAGAIN if the specified nr_events exceeds the user's limit
1236 * of available events. May fail with -ENOMEM if insufficient kernel
1237 * resources are available. May fail with -EFAULT if an invalid
1238 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1239 * implemented.
1240 */
1241asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)
1242{
1243 struct kioctx *ioctx = NULL;
1244 unsigned long ctx;
1245 long ret;
1246
1247 ret = get_user(ctx, ctxp);
1248 if (unlikely(ret))
1249 goto out;
1250
1251 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001252 if (unlikely(ctx || nr_events == 0)) {
1253 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1254 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 goto out;
1256 }
1257
1258 ioctx = ioctx_alloc(nr_events);
1259 ret = PTR_ERR(ioctx);
1260 if (!IS_ERR(ioctx)) {
1261 ret = put_user(ioctx->user_id, ctxp);
1262 if (!ret)
1263 return 0;
1264
1265 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1266 io_destroy(ioctx);
1267 }
1268
1269out:
1270 return ret;
1271}
1272
1273/* sys_io_destroy:
1274 * Destroy the aio_context specified. May cancel any outstanding
1275 * AIOs and block on completion. Will fail with -ENOSYS if not
1276 * implemented. May fail with -EFAULT if the context pointed to
1277 * is invalid.
1278 */
1279asmlinkage long sys_io_destroy(aio_context_t ctx)
1280{
1281 struct kioctx *ioctx = lookup_ioctx(ctx);
1282 if (likely(NULL != ioctx)) {
1283 io_destroy(ioctx);
1284 return 0;
1285 }
1286 pr_debug("EINVAL: io_destroy: invalid context id\n");
1287 return -EINVAL;
1288}
1289
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001290static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1291{
1292 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1293
1294 BUG_ON(ret <= 0);
1295
1296 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1297 ssize_t this = min((ssize_t)iov->iov_len, ret);
1298 iov->iov_base += this;
1299 iov->iov_len -= this;
1300 iocb->ki_left -= this;
1301 ret -= this;
1302 if (iov->iov_len == 0) {
1303 iocb->ki_cur_seg++;
1304 iov++;
1305 }
1306 }
1307
1308 /* the caller should not have done more io than what fit in
1309 * the remaining iovecs */
1310 BUG_ON(ret > 0 && iocb->ki_left == 0);
1311}
1312
1313static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314{
1315 struct file *file = iocb->ki_filp;
1316 struct address_space *mapping = file->f_mapping;
1317 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001318 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1319 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001321 unsigned short opcode;
1322
1323 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1324 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1325 rw_op = file->f_op->aio_read;
1326 opcode = IOCB_CMD_PREADV;
1327 } else {
1328 rw_op = file->f_op->aio_write;
1329 opcode = IOCB_CMD_PWRITEV;
1330 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331
Rusty Russellc2ec6682008-02-08 04:20:15 -08001332 /* This matches the pread()/pwrite() logic */
1333 if (iocb->ki_pos < 0)
1334 return -EINVAL;
1335
Zach Brown897f15f2005-09-30 11:58:55 -07001336 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001337 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1338 iocb->ki_nr_segs - iocb->ki_cur_seg,
1339 iocb->ki_pos);
1340 if (ret > 0)
1341 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001342
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001343 /* retry all partial writes. retry partial reads as long as its a
1344 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001345 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001346 (opcode == IOCB_CMD_PWRITEV ||
1347 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348
1349 /* This means we must have transferred all that we could */
1350 /* No need to retry anymore */
1351 if ((ret == 0) || (iocb->ki_left == 0))
1352 ret = iocb->ki_nbytes - iocb->ki_left;
1353
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001354 /* If we managed to write some out we return that, rather than
1355 * the eventual error. */
1356 if (opcode == IOCB_CMD_PWRITEV
1357 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1358 && iocb->ki_nbytes - iocb->ki_left)
1359 ret = iocb->ki_nbytes - iocb->ki_left;
1360
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 return ret;
1362}
1363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364static ssize_t aio_fdsync(struct kiocb *iocb)
1365{
1366 struct file *file = iocb->ki_filp;
1367 ssize_t ret = -EINVAL;
1368
1369 if (file->f_op->aio_fsync)
1370 ret = file->f_op->aio_fsync(iocb, 1);
1371 return ret;
1372}
1373
1374static ssize_t aio_fsync(struct kiocb *iocb)
1375{
1376 struct file *file = iocb->ki_filp;
1377 ssize_t ret = -EINVAL;
1378
1379 if (file->f_op->aio_fsync)
1380 ret = file->f_op->aio_fsync(iocb, 0);
1381 return ret;
1382}
1383
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001384static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
1385{
1386 ssize_t ret;
1387
1388 ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
1389 kiocb->ki_nbytes, 1,
1390 &kiocb->ki_inline_vec, &kiocb->ki_iovec);
1391 if (ret < 0)
1392 goto out;
1393
1394 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1395 kiocb->ki_cur_seg = 0;
1396 /* ki_nbytes/left now reflect bytes instead of segs */
1397 kiocb->ki_nbytes = ret;
1398 kiocb->ki_left = ret;
1399
1400 ret = 0;
1401out:
1402 return ret;
1403}
1404
1405static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1406{
1407 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1408 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1409 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1410 kiocb->ki_nr_segs = 1;
1411 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001412 return 0;
1413}
1414
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415/*
1416 * aio_setup_iocb:
1417 * Performs the initial checks and aio retry method
1418 * setup for the kiocb at the time of io submission.
1419 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001420static ssize_t aio_setup_iocb(struct kiocb *kiocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421{
1422 struct file *file = kiocb->ki_filp;
1423 ssize_t ret = 0;
1424
1425 switch (kiocb->ki_opcode) {
1426 case IOCB_CMD_PREAD:
1427 ret = -EBADF;
1428 if (unlikely(!(file->f_mode & FMODE_READ)))
1429 break;
1430 ret = -EFAULT;
1431 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1432 kiocb->ki_left)))
1433 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001434 ret = security_file_permission(file, MAY_READ);
1435 if (unlikely(ret))
1436 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001437 ret = aio_setup_single_vector(kiocb);
1438 if (ret)
1439 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 ret = -EINVAL;
1441 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001442 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 break;
1444 case IOCB_CMD_PWRITE:
1445 ret = -EBADF;
1446 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1447 break;
1448 ret = -EFAULT;
1449 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1450 kiocb->ki_left)))
1451 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001452 ret = security_file_permission(file, MAY_WRITE);
1453 if (unlikely(ret))
1454 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001455 ret = aio_setup_single_vector(kiocb);
1456 if (ret)
1457 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 ret = -EINVAL;
1459 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001460 kiocb->ki_retry = aio_rw_vect_retry;
1461 break;
1462 case IOCB_CMD_PREADV:
1463 ret = -EBADF;
1464 if (unlikely(!(file->f_mode & FMODE_READ)))
1465 break;
1466 ret = security_file_permission(file, MAY_READ);
1467 if (unlikely(ret))
1468 break;
1469 ret = aio_setup_vectored_rw(READ, kiocb);
1470 if (ret)
1471 break;
1472 ret = -EINVAL;
1473 if (file->f_op->aio_read)
1474 kiocb->ki_retry = aio_rw_vect_retry;
1475 break;
1476 case IOCB_CMD_PWRITEV:
1477 ret = -EBADF;
1478 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1479 break;
1480 ret = security_file_permission(file, MAY_WRITE);
1481 if (unlikely(ret))
1482 break;
1483 ret = aio_setup_vectored_rw(WRITE, kiocb);
1484 if (ret)
1485 break;
1486 ret = -EINVAL;
1487 if (file->f_op->aio_write)
1488 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 break;
1490 case IOCB_CMD_FDSYNC:
1491 ret = -EINVAL;
1492 if (file->f_op->aio_fsync)
1493 kiocb->ki_retry = aio_fdsync;
1494 break;
1495 case IOCB_CMD_FSYNC:
1496 ret = -EINVAL;
1497 if (file->f_op->aio_fsync)
1498 kiocb->ki_retry = aio_fsync;
1499 break;
1500 default:
1501 dprintk("EINVAL: io_submit: no operation provided\n");
1502 ret = -EINVAL;
1503 }
1504
1505 if (!kiocb->ki_retry)
1506 return ret;
1507
1508 return 0;
1509}
1510
1511/*
1512 * aio_wake_function:
1513 * wait queue callback function for aio notification,
1514 * Simply triggers a retry of the operation via kick_iocb.
1515 *
1516 * This callback is specified in the wait queue entry in
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -07001517 * a kiocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 *
1519 * Note:
1520 * This routine is executed with the wait queue lock held.
1521 * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
1522 * the ioctx lock inside the wait queue lock. This is safe
1523 * because this callback isn't used for wait queues which
1524 * are nested inside ioctx lock (i.e. ctx->wait)
1525 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001526static int aio_wake_function(wait_queue_t *wait, unsigned mode,
1527 int sync, void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528{
1529 struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
1530
1531 list_del_init(&wait->task_list);
1532 kick_iocb(iocb);
1533 return 1;
1534}
1535
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001536int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537 struct iocb *iocb)
1538{
1539 struct kiocb *req;
1540 struct file *file;
1541 ssize_t ret;
1542
1543 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001544 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 pr_debug("EINVAL: io_submit: reserve field set\n");
1546 return -EINVAL;
1547 }
1548
1549 /* prevent overflows */
1550 if (unlikely(
1551 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1552 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1553 ((ssize_t)iocb->aio_nbytes < 0)
1554 )) {
1555 pr_debug("EINVAL: io_submit: overflow check\n");
1556 return -EINVAL;
1557 }
1558
1559 file = fget(iocb->aio_fildes);
1560 if (unlikely(!file))
1561 return -EBADF;
1562
1563 req = aio_get_req(ctx); /* returns with 2 references to req */
1564 if (unlikely(!req)) {
1565 fput(file);
1566 return -EAGAIN;
1567 }
Yan Zheng87e28312007-10-08 12:16:20 -07001568 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001569 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1570 /*
1571 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1572 * instance of the file* now. The file descriptor must be
1573 * an eventfd() fd, and will be signaled for each completed
1574 * event using the eventfd_signal() function.
1575 */
1576 req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
1577 if (unlikely(IS_ERR(req->ki_eventfd))) {
1578 ret = PTR_ERR(req->ki_eventfd);
1579 goto out_put_req;
1580 }
1581 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582
Ken Chen212079c2005-05-01 08:59:15 -07001583 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584 if (unlikely(ret)) {
1585 dprintk("EFAULT: aio_key\n");
1586 goto out_put_req;
1587 }
1588
1589 req->ki_obj.user = user_iocb;
1590 req->ki_user_data = iocb->aio_data;
1591 req->ki_pos = iocb->aio_offset;
1592
1593 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1594 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1595 req->ki_opcode = iocb->aio_lio_opcode;
1596 init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
1597 INIT_LIST_HEAD(&req->ki_wait.task_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001598
1599 ret = aio_setup_iocb(req);
1600
1601 if (ret)
1602 goto out_put_req;
1603
1604 spin_lock_irq(&ctx->ctx_lock);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001605 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001606 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001607 /* drain the run list */
1608 while (__aio_run_iocbs(ctx))
1609 ;
1610 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611 spin_unlock_irq(&ctx->ctx_lock);
1612 aio_put_req(req); /* drop extra ref to req */
1613 return 0;
1614
1615out_put_req:
1616 aio_put_req(req); /* drop extra ref to req */
1617 aio_put_req(req); /* drop i/o ref to req */
1618 return ret;
1619}
1620
1621/* sys_io_submit:
1622 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1623 * the number of iocbs queued. May return -EINVAL if the aio_context
1624 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1625 * *iocbpp[0] is not properly initialized, if the operation specified
1626 * is invalid for the file descriptor in the iocb. May fail with
1627 * -EFAULT if any of the data structures point to invalid data. May
1628 * fail with -EBADF if the file descriptor specified in the first
1629 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1630 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1631 * fail with -ENOSYS if not implemented.
1632 */
1633asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
1634 struct iocb __user * __user *iocbpp)
1635{
1636 struct kioctx *ctx;
1637 long ret = 0;
1638 int i;
1639
1640 if (unlikely(nr < 0))
1641 return -EINVAL;
1642
1643 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1644 return -EFAULT;
1645
1646 ctx = lookup_ioctx(ctx_id);
1647 if (unlikely(!ctx)) {
1648 pr_debug("EINVAL: io_submit: invalid context id\n");
1649 return -EINVAL;
1650 }
1651
1652 /*
1653 * AKPM: should this return a partial result if some of the IOs were
1654 * successfully submitted?
1655 */
1656 for (i=0; i<nr; i++) {
1657 struct iocb __user *user_iocb;
1658 struct iocb tmp;
1659
1660 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1661 ret = -EFAULT;
1662 break;
1663 }
1664
1665 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1666 ret = -EFAULT;
1667 break;
1668 }
1669
1670 ret = io_submit_one(ctx, user_iocb, &tmp);
1671 if (ret)
1672 break;
1673 }
1674
1675 put_ioctx(ctx);
1676 return i ? i : ret;
1677}
1678
1679/* lookup_kiocb
1680 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001682static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1683 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684{
1685 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001686
1687 assert_spin_locked(&ctx->ctx_lock);
1688
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 /* TODO: use a hash or array, this sucks. */
1690 list_for_each(pos, &ctx->active_reqs) {
1691 struct kiocb *kiocb = list_kiocb(pos);
1692 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1693 return kiocb;
1694 }
1695 return NULL;
1696}
1697
1698/* sys_io_cancel:
1699 * Attempts to cancel an iocb previously passed to io_submit. If
1700 * the operation is successfully cancelled, the resulting event is
1701 * copied into the memory pointed to by result without being placed
1702 * into the completion queue and 0 is returned. May fail with
1703 * -EFAULT if any of the data structures pointed to are invalid.
1704 * May fail with -EINVAL if aio_context specified by ctx_id is
1705 * invalid. May fail with -EAGAIN if the iocb specified was not
1706 * cancelled. Will fail with -ENOSYS if not implemented.
1707 */
1708asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
1709 struct io_event __user *result)
1710{
1711 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1712 struct kioctx *ctx;
1713 struct kiocb *kiocb;
1714 u32 key;
1715 int ret;
1716
1717 ret = get_user(key, &iocb->aio_key);
1718 if (unlikely(ret))
1719 return -EFAULT;
1720
1721 ctx = lookup_ioctx(ctx_id);
1722 if (unlikely(!ctx))
1723 return -EINVAL;
1724
1725 spin_lock_irq(&ctx->ctx_lock);
1726 ret = -EAGAIN;
1727 kiocb = lookup_kiocb(ctx, iocb, key);
1728 if (kiocb && kiocb->ki_cancel) {
1729 cancel = kiocb->ki_cancel;
1730 kiocb->ki_users ++;
1731 kiocbSetCancelled(kiocb);
1732 } else
1733 cancel = NULL;
1734 spin_unlock_irq(&ctx->ctx_lock);
1735
1736 if (NULL != cancel) {
1737 struct io_event tmp;
1738 pr_debug("calling cancel\n");
1739 memset(&tmp, 0, sizeof(tmp));
1740 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1741 tmp.data = kiocb->ki_user_data;
1742 ret = cancel(kiocb, &tmp);
1743 if (!ret) {
1744 /* Cancellation succeeded -- copy the result
1745 * into the user's buffer.
1746 */
1747 if (copy_to_user(result, &tmp, sizeof(tmp)))
1748 ret = -EFAULT;
1749 }
1750 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001751 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752
1753 put_ioctx(ctx);
1754
1755 return ret;
1756}
1757
1758/* io_getevents:
1759 * Attempts to read at least min_nr events and up to nr events from
1760 * the completion queue for the aio_context specified by ctx_id. May
1761 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1762 * if nr is out of range, if when is out of range. May fail with
1763 * -EFAULT if any of the memory specified to is invalid. May return
1764 * 0 or < min_nr if no events are available and the timeout specified
1765 * by when has elapsed, where when == NULL specifies an infinite
1766 * timeout. Note that the timeout pointed to by when is relative and
1767 * will be updated if not NULL and the operation blocks. Will fail
1768 * with -ENOSYS if not implemented.
1769 */
1770asmlinkage long sys_io_getevents(aio_context_t ctx_id,
1771 long min_nr,
1772 long nr,
1773 struct io_event __user *events,
1774 struct timespec __user *timeout)
1775{
1776 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1777 long ret = -EINVAL;
1778
1779 if (likely(ioctx)) {
1780 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1781 ret = read_events(ioctx, min_nr, nr, events, timeout);
1782 put_ioctx(ioctx);
1783 }
1784
1785 return ret;
1786}
1787
1788__initcall(aio_setup);
1789
1790EXPORT_SYMBOL(aio_complete);
1791EXPORT_SYMBOL(aio_put_req);
1792EXPORT_SYMBOL(wait_on_sync_kiocb);