blob: 0051fd94b44e7e75bde7882b2d9c074a1d1f8188 [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
Adrian Bunkd5470b52008-04-29 00:58:57 -0700194
195/* __put_ioctx
196 * Called when the last user of an aio context has gone away,
197 * and the struct needs to be freed.
198 */
199static void __put_ioctx(struct kioctx *ctx)
200{
201 unsigned nr_events = ctx->max_reqs;
202
203 BUG_ON(ctx->reqs_active);
204
205 cancel_delayed_work(&ctx->wq);
206 cancel_work_sync(&ctx->wq.work);
207 aio_free_ring(ctx);
208 mmdrop(ctx->mm);
209 ctx->mm = NULL;
210 pr_debug("__put_ioctx: freeing %p\n", ctx);
211 kmem_cache_free(kioctx_cachep, ctx);
212
213 if (nr_events) {
214 spin_lock(&aio_nr_lock);
215 BUG_ON(aio_nr - nr_events > aio_nr);
216 aio_nr -= nr_events;
217 spin_unlock(&aio_nr_lock);
218 }
219}
220
221#define get_ioctx(kioctx) do { \
222 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
223 atomic_inc(&(kioctx)->users); \
224} while (0)
225#define put_ioctx(kioctx) do { \
226 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
227 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
228 __put_ioctx(kioctx); \
229} while (0)
230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231/* ioctx_alloc
232 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
233 */
234static struct kioctx *ioctx_alloc(unsigned nr_events)
235{
236 struct mm_struct *mm;
237 struct kioctx *ctx;
238
239 /* Prevent overflows */
240 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
241 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
242 pr_debug("ENOMEM: nr_events too high\n");
243 return ERR_PTR(-EINVAL);
244 }
245
Zach Brownd55b5fd2005-11-07 00:59:31 -0800246 if ((unsigned long)nr_events > aio_max_nr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 return ERR_PTR(-EAGAIN);
248
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800249 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 if (!ctx)
251 return ERR_PTR(-ENOMEM);
252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 ctx->max_reqs = nr_events;
254 mm = ctx->mm = current->mm;
255 atomic_inc(&mm->mm_count);
256
257 atomic_set(&ctx->users, 1);
258 spin_lock_init(&ctx->ctx_lock);
259 spin_lock_init(&ctx->ring_info.ring_lock);
260 init_waitqueue_head(&ctx->wait);
261
262 INIT_LIST_HEAD(&ctx->active_reqs);
263 INIT_LIST_HEAD(&ctx->run_list);
David Howells65f27f32006-11-22 14:55:48 +0000264 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265
266 if (aio_setup_ring(ctx) < 0)
267 goto out_freectx;
268
269 /* limit the number of system wide aios */
Zach Brownd55b5fd2005-11-07 00:59:31 -0800270 spin_lock(&aio_nr_lock);
271 if (aio_nr + ctx->max_reqs > aio_max_nr ||
272 aio_nr + ctx->max_reqs < aio_nr)
273 ctx->max_reqs = 0;
274 else
275 aio_nr += ctx->max_reqs;
276 spin_unlock(&aio_nr_lock);
277 if (ctx->max_reqs == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 goto out_cleanup;
279
Jeff Moyer39fa0032008-04-29 01:03:48 -0700280 /* now link into global list. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 write_lock(&mm->ioctx_list_lock);
282 ctx->next = mm->ioctx_list;
283 mm->ioctx_list = ctx;
284 write_unlock(&mm->ioctx_list_lock);
285
286 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
287 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
288 return ctx;
289
290out_cleanup:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 __put_ioctx(ctx);
292 return ERR_PTR(-EAGAIN);
293
294out_freectx:
295 mmdrop(mm);
296 kmem_cache_free(kioctx_cachep, ctx);
297 ctx = ERR_PTR(-ENOMEM);
298
299 dprintk("aio: error allocating ioctx %p\n", ctx);
300 return ctx;
301}
302
303/* aio_cancel_all
304 * Cancels all outstanding aio requests on an aio context. Used
305 * when the processes owning a context have all exited to encourage
306 * the rapid destruction of the kioctx.
307 */
308static void aio_cancel_all(struct kioctx *ctx)
309{
310 int (*cancel)(struct kiocb *, struct io_event *);
311 struct io_event res;
312 spin_lock_irq(&ctx->ctx_lock);
313 ctx->dead = 1;
314 while (!list_empty(&ctx->active_reqs)) {
315 struct list_head *pos = ctx->active_reqs.next;
316 struct kiocb *iocb = list_kiocb(pos);
317 list_del_init(&iocb->ki_list);
318 cancel = iocb->ki_cancel;
319 kiocbSetCancelled(iocb);
320 if (cancel) {
321 iocb->ki_users++;
322 spin_unlock_irq(&ctx->ctx_lock);
323 cancel(iocb, &res);
324 spin_lock_irq(&ctx->ctx_lock);
325 }
326 }
327 spin_unlock_irq(&ctx->ctx_lock);
328}
329
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700330static void wait_for_all_aios(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331{
332 struct task_struct *tsk = current;
333 DECLARE_WAITQUEUE(wait, tsk);
334
Ken Chendee11c22007-02-03 01:13:45 -0800335 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 if (!ctx->reqs_active)
Ken Chendee11c22007-02-03 01:13:45 -0800337 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 add_wait_queue(&ctx->wait, &wait);
340 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
341 while (ctx->reqs_active) {
Ken Chendee11c22007-02-03 01:13:45 -0800342 spin_unlock_irq(&ctx->ctx_lock);
Jeff Moyer41d10da2007-10-16 23:27:20 -0700343 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
Ken Chendee11c22007-02-03 01:13:45 -0800345 spin_lock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 }
347 __set_task_state(tsk, TASK_RUNNING);
348 remove_wait_queue(&ctx->wait, &wait);
Ken Chendee11c22007-02-03 01:13:45 -0800349
350out:
351 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352}
353
354/* wait_on_sync_kiocb:
355 * Waits on the given sync kiocb to complete.
356 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800357ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358{
359 while (iocb->ki_users) {
360 set_current_state(TASK_UNINTERRUPTIBLE);
361 if (!iocb->ki_users)
362 break;
Jeff Moyer41d10da2007-10-16 23:27:20 -0700363 io_schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 }
365 __set_current_state(TASK_RUNNING);
366 return iocb->ki_user_data;
367}
368
369/* exit_aio: called when the last user of mm goes away. At this point,
370 * there is no way for any new requests to be submited or any of the
371 * io_* syscalls to be called on the context. However, there may be
372 * outstanding requests which hold references to the context; as they
373 * go away, they will call put_ioctx and release any pinned memory
374 * associated with the request (held via struct page * references).
375 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800376void exit_aio(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377{
378 struct kioctx *ctx = mm->ioctx_list;
379 mm->ioctx_list = NULL;
380 while (ctx) {
381 struct kioctx *next = ctx->next;
382 ctx->next = NULL;
383 aio_cancel_all(ctx);
384
385 wait_for_all_aios(ctx);
386 /*
Andrew Mortona9df62c2007-05-09 02:33:54 -0700387 * Ensure we don't leave the ctx on the aio_wq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 */
Oleg Nesterov28e53bd2007-05-09 02:34:22 -0700389 cancel_work_sync(&ctx->wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390
391 if (1 != atomic_read(&ctx->users))
392 printk(KERN_DEBUG
393 "exit_aio:ioctx still alive: %d %d %d\n",
394 atomic_read(&ctx->users), ctx->dead,
395 ctx->reqs_active);
396 put_ioctx(ctx);
397 ctx = next;
398 }
399}
400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401/* aio_get_req
402 * Allocate a slot for an aio request. Increments the users count
403 * of the kioctx so that the kioctx stays around until all requests are
404 * complete. Returns NULL if no requests are free.
405 *
406 * Returns with kiocb->users set to 2. The io submit code path holds
407 * an extra reference while submitting the i/o.
408 * This prevents races between the aio code path referencing the
409 * req (after submitting it) and aio_complete() freeing the req.
410 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800411static struct kiocb *__aio_get_req(struct kioctx *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412{
413 struct kiocb *req = NULL;
414 struct aio_ring *ring;
415 int okay = 0;
416
417 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
418 if (unlikely(!req))
419 return NULL;
420
Zach Brown4faa5282005-10-17 16:43:33 -0700421 req->ki_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 req->ki_users = 2;
423 req->ki_key = 0;
424 req->ki_ctx = ctx;
425 req->ki_cancel = NULL;
426 req->ki_retry = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 req->ki_dtor = NULL;
428 req->private = NULL;
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700429 req->ki_iovec = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 INIT_LIST_HEAD(&req->ki_run_list);
Davide Libenzi9c3060b2007-05-10 22:23:21 -0700431 req->ki_eventfd = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
433 /* Check if the completion queue has enough free space to
434 * accept an event from this io.
435 */
436 spin_lock_irq(&ctx->ctx_lock);
437 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
438 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
439 list_add(&req->ki_list, &ctx->active_reqs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 ctx->reqs_active++;
441 okay = 1;
442 }
443 kunmap_atomic(ring, KM_USER0);
444 spin_unlock_irq(&ctx->ctx_lock);
445
446 if (!okay) {
447 kmem_cache_free(kiocb_cachep, req);
448 req = NULL;
449 }
450
451 return req;
452}
453
454static inline struct kiocb *aio_get_req(struct kioctx *ctx)
455{
456 struct kiocb *req;
457 /* Handle a potential starvation case -- should be exceedingly rare as
458 * requests will be stuck on fput_head only if the aio_fput_routine is
459 * delayed and the requests were the last user of the struct file.
460 */
461 req = __aio_get_req(ctx);
462 if (unlikely(NULL == req)) {
463 aio_fput_routine(NULL);
464 req = __aio_get_req(ctx);
465 }
466 return req;
467}
468
469static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
470{
Zach Brownd00689a2005-11-13 16:07:34 -0800471 assert_spin_locked(&ctx->ctx_lock);
472
Davide Libenzi9c3060b2007-05-10 22:23:21 -0700473 if (!IS_ERR(req->ki_eventfd))
474 fput(req->ki_eventfd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (req->ki_dtor)
476 req->ki_dtor(req);
Badari Pulavartyeed4e512006-09-30 23:28:49 -0700477 if (req->ki_iovec != &req->ki_inline_vec)
478 kfree(req->ki_iovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 kmem_cache_free(kiocb_cachep, req);
480 ctx->reqs_active--;
481
482 if (unlikely(!ctx->reqs_active && ctx->dead))
483 wake_up(&ctx->wait);
484}
485
David Howells65f27f32006-11-22 14:55:48 +0000486static void aio_fput_routine(struct work_struct *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487{
488 spin_lock_irq(&fput_lock);
489 while (likely(!list_empty(&fput_head))) {
490 struct kiocb *req = list_kiocb(fput_head.next);
491 struct kioctx *ctx = req->ki_ctx;
492
493 list_del(&req->ki_list);
494 spin_unlock_irq(&fput_lock);
495
496 /* Complete the fput */
497 __fput(req->ki_filp);
498
499 /* Link the iocb into the context's free list */
500 spin_lock_irq(&ctx->ctx_lock);
501 really_put_req(ctx, req);
502 spin_unlock_irq(&ctx->ctx_lock);
503
504 put_ioctx(ctx);
505 spin_lock_irq(&fput_lock);
506 }
507 spin_unlock_irq(&fput_lock);
508}
509
510/* __aio_put_req
511 * Returns true if this put was the last user of the request.
512 */
513static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
514{
515 dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
516 req, atomic_read(&req->ki_filp->f_count));
517
Zach Brownd00689a2005-11-13 16:07:34 -0800518 assert_spin_locked(&ctx->ctx_lock);
519
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 req->ki_users --;
Eric Sesterhenn93e06b42006-11-30 05:29:23 +0100521 BUG_ON(req->ki_users < 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 if (likely(req->ki_users))
523 return 0;
524 list_del(&req->ki_list); /* remove from active_reqs */
525 req->ki_cancel = NULL;
526 req->ki_retry = NULL;
527
528 /* Must be done under the lock to serialise against cancellation.
529 * Call this aio_fput as it duplicates fput via the fput_work.
530 */
Nick Piggin095975d2006-01-08 01:02:19 -0800531 if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 get_ioctx(ctx);
533 spin_lock(&fput_lock);
534 list_add(&req->ki_list, &fput_head);
535 spin_unlock(&fput_lock);
536 queue_work(aio_wq, &fput_work);
537 } else
538 really_put_req(ctx, req);
539 return 1;
540}
541
542/* aio_put_req
543 * Returns true if this put was the last user of the kiocb,
544 * false if the request is still in use.
545 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800546int aio_put_req(struct kiocb *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547{
548 struct kioctx *ctx = req->ki_ctx;
549 int ret;
550 spin_lock_irq(&ctx->ctx_lock);
551 ret = __aio_put_req(ctx, req);
552 spin_unlock_irq(&ctx->ctx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 return ret;
554}
555
Adrian Bunkd5470b52008-04-29 00:58:57 -0700556static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557{
558 struct kioctx *ioctx;
559 struct mm_struct *mm;
560
561 mm = current->mm;
562 read_lock(&mm->ioctx_list_lock);
563 for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next)
564 if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) {
565 get_ioctx(ioctx);
566 break;
567 }
568 read_unlock(&mm->ioctx_list_lock);
569
570 return ioctx;
571}
572
573/*
574 * use_mm
575 * Makes the calling kernel thread take on the specified
576 * mm context.
577 * Called by the retry thread execute retries within the
578 * iocb issuer's mm context, so that copy_from/to_user
579 * operations work seamlessly for aio.
580 * (Note: this routine is intended to be called only
581 * from a kernel thread context)
582 */
583static void use_mm(struct mm_struct *mm)
584{
585 struct mm_struct *active_mm;
586 struct task_struct *tsk = current;
587
588 task_lock(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 active_mm = tsk->active_mm;
590 atomic_inc(&mm->mm_count);
591 tsk->mm = mm;
592 tsk->active_mm = mm;
Jeremy Fitzhardinge90aef122006-12-13 00:34:49 -0800593 switch_mm(active_mm, mm, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 task_unlock(tsk);
595
596 mmdrop(active_mm);
597}
598
599/*
600 * unuse_mm
601 * Reverses the effect of use_mm, i.e. releases the
602 * specified mm context which was earlier taken on
603 * by the calling kernel thread
604 * (Note: this routine is intended to be called only
605 * from a kernel thread context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -0700607static void unuse_mm(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608{
609 struct task_struct *tsk = current;
610
611 task_lock(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 tsk->mm = NULL;
613 /* active_mm is still 'mm' */
614 enter_lazy_tlb(mm, tsk);
615 task_unlock(tsk);
616}
617
618/*
619 * Queue up a kiocb to be retried. Assumes that the kiocb
620 * has already been marked as kicked, and places it on
621 * the retry run list for the corresponding ioctx, if it
622 * isn't already queued. Returns 1 if it actually queued
623 * the kiocb (to tell the caller to activate the work
624 * queue to process it), or 0, if it found that it was
625 * already queued.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 */
627static inline int __queue_kicked_iocb(struct kiocb *iocb)
628{
629 struct kioctx *ctx = iocb->ki_ctx;
630
Zach Brownd00689a2005-11-13 16:07:34 -0800631 assert_spin_locked(&ctx->ctx_lock);
632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if (list_empty(&iocb->ki_run_list)) {
634 list_add_tail(&iocb->ki_run_list,
635 &ctx->run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 return 1;
637 }
638 return 0;
639}
640
641/* aio_run_iocb
642 * This is the core aio execution routine. It is
643 * invoked both for initial i/o submission and
644 * subsequent retries via the aio_kick_handler.
645 * Expects to be invoked with iocb->ki_ctx->lock
Andreas Mohrd6e05ed2006-06-26 18:35:02 +0200646 * already held. The lock is released and reacquired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 * as needed during processing.
648 *
649 * Calls the iocb retry method (already setup for the
650 * iocb on initial submission) for operation specific
651 * handling, but takes care of most of common retry
652 * execution details for a given iocb. The retry method
653 * needs to be non-blocking as far as possible, to avoid
654 * holding up other iocbs waiting to be serviced by the
655 * retry kernel thread.
656 *
657 * The trickier parts in this code have to do with
658 * ensuring that only one retry instance is in progress
659 * for a given iocb at any time. Providing that guarantee
660 * simplifies the coding of individual aio operations as
661 * it avoids various potential races.
662 */
663static ssize_t aio_run_iocb(struct kiocb *iocb)
664{
665 struct kioctx *ctx = iocb->ki_ctx;
666 ssize_t (*retry)(struct kiocb *);
667 ssize_t ret;
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 if (!(retry = iocb->ki_retry)) {
670 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
671 return 0;
672 }
673
674 /*
675 * We don't want the next retry iteration for this
676 * operation to start until this one has returned and
677 * updated the iocb state. However, wait_queue functions
678 * can trigger a kick_iocb from interrupt context in the
679 * meantime, indicating that data is available for the next
680 * iteration. We want to remember that and enable the
681 * next retry iteration _after_ we are through with
682 * this one.
683 *
684 * So, in order to be able to register a "kick", but
685 * prevent it from being queued now, we clear the kick
686 * flag, but make the kick code *think* that the iocb is
687 * still on the run list until we are actually done.
688 * When we are done with this iteration, we check if
689 * the iocb was kicked in the meantime and if so, queue
690 * it up afresh.
691 */
692
693 kiocbClearKicked(iocb);
694
695 /*
696 * This is so that aio_complete knows it doesn't need to
697 * pull the iocb off the run list (We can't just call
698 * INIT_LIST_HEAD because we don't want a kick_iocb to
699 * queue this on the run list yet)
700 */
701 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
702 spin_unlock_irq(&ctx->ctx_lock);
703
704 /* Quit retrying if the i/o has been cancelled */
705 if (kiocbIsCancelled(iocb)) {
706 ret = -EINTR;
707 aio_complete(iocb, ret, 0);
708 /* must not access the iocb after this */
709 goto out;
710 }
711
712 /*
713 * Now we are all set to call the retry method in async
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -0700714 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 ret = retry(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
Zach Brown897f15f2005-09-30 11:58:55 -0700718 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
719 BUG_ON(!list_empty(&iocb->ki_wait.task_list));
720 aio_complete(iocb, ret, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 }
722out:
723 spin_lock_irq(&ctx->ctx_lock);
724
725 if (-EIOCBRETRY == ret) {
726 /*
727 * OK, now that we are done with this iteration
728 * and know that there is more left to go,
729 * this is where we let go so that a subsequent
730 * "kick" can start the next iteration
731 */
732
733 /* will make __queue_kicked_iocb succeed from here on */
734 INIT_LIST_HEAD(&iocb->ki_run_list);
735 /* we must queue the next iteration ourselves, if it
736 * has already been kicked */
737 if (kiocbIsKicked(iocb)) {
738 __queue_kicked_iocb(iocb);
Sébastien Duguc016e222005-06-28 20:44:59 -0700739
740 /*
741 * __queue_kicked_iocb will always return 1 here, because
742 * iocb->ki_run_list is empty at this point so it should
743 * be safe to unconditionally queue the context into the
744 * work queue.
745 */
746 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 }
748 }
749 return ret;
750}
751
752/*
753 * __aio_run_iocbs:
754 * Process all pending retries queued on the ioctx
755 * run list.
756 * Assumes it is operating within the aio issuer's mm
Zach Brownd00689a2005-11-13 16:07:34 -0800757 * context.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 */
759static int __aio_run_iocbs(struct kioctx *ctx)
760{
761 struct kiocb *iocb;
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700762 struct list_head run_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
Zach Brownd00689a2005-11-13 16:07:34 -0800764 assert_spin_locked(&ctx->ctx_lock);
765
Oleg Nesterov626ab0e2006-06-23 02:05:55 -0700766 list_replace_init(&ctx->run_list, &run_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 while (!list_empty(&run_list)) {
768 iocb = list_entry(run_list.next, struct kiocb,
769 ki_run_list);
770 list_del(&iocb->ki_run_list);
771 /*
772 * Hold an extra reference while retrying i/o.
773 */
774 iocb->ki_users++; /* grab extra reference */
775 aio_run_iocb(iocb);
Ken Chendee11c22007-02-03 01:13:45 -0800776 __aio_put_req(ctx, iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 if (!list_empty(&ctx->run_list))
779 return 1;
780 return 0;
781}
782
783static void aio_queue_work(struct kioctx * ctx)
784{
785 unsigned long timeout;
786 /*
787 * if someone is waiting, get the work started right
788 * away, otherwise, use a longer delay
789 */
790 smp_mb();
791 if (waitqueue_active(&ctx->wait))
792 timeout = 1;
793 else
794 timeout = HZ/10;
795 queue_delayed_work(aio_wq, &ctx->wq, timeout);
796}
797
798
799/*
800 * aio_run_iocbs:
801 * Process all pending retries queued on the ioctx
802 * run list.
803 * Assumes it is operating within the aio issuer's mm
804 * context.
805 */
806static inline void aio_run_iocbs(struct kioctx *ctx)
807{
808 int requeue;
809
810 spin_lock_irq(&ctx->ctx_lock);
811
812 requeue = __aio_run_iocbs(ctx);
813 spin_unlock_irq(&ctx->ctx_lock);
814 if (requeue)
815 aio_queue_work(ctx);
816}
817
818/*
819 * just like aio_run_iocbs, but keeps running them until
820 * the list stays empty
821 */
822static inline void aio_run_all_iocbs(struct kioctx *ctx)
823{
824 spin_lock_irq(&ctx->ctx_lock);
825 while (__aio_run_iocbs(ctx))
826 ;
827 spin_unlock_irq(&ctx->ctx_lock);
828}
829
830/*
831 * aio_kick_handler:
832 * Work queue handler triggered to process pending
833 * retries on an ioctx. Takes on the aio issuer's
834 * mm context before running the iocbs, so that
835 * copy_xxx_user operates on the issuer's address
836 * space.
837 * Run on aiod's context.
838 */
David Howells65f27f32006-11-22 14:55:48 +0000839static void aio_kick_handler(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840{
David Howells65f27f32006-11-22 14:55:48 +0000841 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 mm_segment_t oldfs = get_fs();
Zach Brown1ebb1102006-12-29 16:47:02 -0800843 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 int requeue;
845
846 set_fs(USER_DS);
847 use_mm(ctx->mm);
848 spin_lock_irq(&ctx->ctx_lock);
849 requeue =__aio_run_iocbs(ctx);
Zach Brown1ebb1102006-12-29 16:47:02 -0800850 mm = ctx->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 spin_unlock_irq(&ctx->ctx_lock);
Zach Brown1ebb1102006-12-29 16:47:02 -0800852 unuse_mm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 set_fs(oldfs);
854 /*
855 * we're in a worker thread already, don't use queue_delayed_work,
856 */
857 if (requeue)
David Howells52bad642006-11-22 14:54:01 +0000858 queue_delayed_work(aio_wq, &ctx->wq, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859}
860
861
862/*
863 * Called by kick_iocb to queue the kiocb for retry
864 * and if required activate the aio work queue to process
865 * it
866 */
Zach Brown998765e2005-09-30 11:58:54 -0700867static void try_queue_kicked_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868{
869 struct kioctx *ctx = iocb->ki_ctx;
870 unsigned long flags;
871 int run = 0;
872
Zach Brown998765e2005-09-30 11:58:54 -0700873 /* We're supposed to be the only path putting the iocb back on the run
874 * list. If we find that the iocb is *back* on a wait queue already
875 * than retry has happened before we could queue the iocb. This also
876 * means that the retry could have completed and freed our iocb, no
877 * good. */
878 BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
880 spin_lock_irqsave(&ctx->ctx_lock, flags);
Zach Brown998765e2005-09-30 11:58:54 -0700881 /* set this inside the lock so that we can't race with aio_run_iocb()
882 * testing it and putting the iocb on the run list under the lock */
883 if (!kiocbTryKick(iocb))
884 run = __queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Ken Chen644d3a02005-05-01 08:59:15 -0700886 if (run)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 aio_queue_work(ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888}
889
890/*
891 * kick_iocb:
892 * Called typically from a wait queue callback context
893 * (aio_wake_function) to trigger a retry of the iocb.
894 * The retry is usually executed by aio workqueue
895 * threads (See aio_kick_handler).
896 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800897void kick_iocb(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898{
899 /* sync iocbs are easy: they can only ever be executing from a
900 * single context. */
901 if (is_sync_kiocb(iocb)) {
902 kiocbSetKicked(iocb);
903 wake_up_process(iocb->ki_obj.tsk);
904 return;
905 }
906
Zach Brown998765e2005-09-30 11:58:54 -0700907 try_queue_kicked_iocb(iocb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908}
909EXPORT_SYMBOL(kick_iocb);
910
911/* aio_complete
912 * Called when the io request on the given iocb is complete.
913 * Returns true if this is the last user of the request. The
914 * only other user of the request can be the cancellation code.
915 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800916int aio_complete(struct kiocb *iocb, long res, long res2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917{
918 struct kioctx *ctx = iocb->ki_ctx;
919 struct aio_ring_info *info;
920 struct aio_ring *ring;
921 struct io_event *event;
922 unsigned long flags;
923 unsigned long tail;
924 int ret;
925
Zach Brown20dcae32005-11-13 16:07:33 -0800926 /*
927 * Special case handling for sync iocbs:
928 * - events go directly into the iocb for fast handling
929 * - the sync task with the iocb in its stack holds the single iocb
930 * ref, no other paths have a way to get another ref
931 * - the sync task helpfully left a reference to itself in the iocb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 */
933 if (is_sync_kiocb(iocb)) {
Zach Brown20dcae32005-11-13 16:07:33 -0800934 BUG_ON(iocb->ki_users != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 iocb->ki_user_data = res;
Zach Brown20dcae32005-11-13 16:07:33 -0800936 iocb->ki_users = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 wake_up_process(iocb->ki_obj.tsk);
Zach Brown20dcae32005-11-13 16:07:33 -0800938 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 }
940
941 info = &ctx->ring_info;
942
943 /* add a completion event to the ring buffer.
944 * must be done holding ctx->ctx_lock to prevent
945 * other code from messing with the tail
946 * pointer since we might be called from irq
947 * context.
948 */
949 spin_lock_irqsave(&ctx->ctx_lock, flags);
950
951 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
952 list_del_init(&iocb->ki_run_list);
953
954 /*
955 * cancelled requests don't get events, userland was given one
956 * when the event got cancelled.
957 */
958 if (kiocbIsCancelled(iocb))
959 goto put_rq;
960
961 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
962
963 tail = info->tail;
964 event = aio_ring_event(info, tail, KM_IRQ0);
Ken Chen4bf69b22005-05-01 08:59:15 -0700965 if (++tail >= info->nr)
966 tail = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
968 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
969 event->data = iocb->ki_user_data;
970 event->res = res;
971 event->res2 = res2;
972
973 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
974 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
975 res, res2);
976
977 /* after flagging the request as done, we
978 * must never even look at it again
979 */
980 smp_wmb(); /* make event visible before updating tail */
981
982 info->tail = tail;
983 ring->tail = tail;
984
985 put_aio_ring_event(event, KM_IRQ0);
986 kunmap_atomic(ring, KM_IRQ1);
987
988 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
Davide Libenzi8d1c98b2008-04-10 21:29:19 -0700989
990 /*
991 * Check if the user asked us to deliver the result through an
992 * eventfd. The eventfd_signal() function is safe to be called
993 * from IRQ context.
994 */
995 if (!IS_ERR(iocb->ki_eventfd))
996 eventfd_signal(iocb->ki_eventfd, 1);
997
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998put_rq:
999 /* everything turned out well, dispose of the aiocb. */
1000 ret = __aio_put_req(ctx, iocb);
1001
Quentin Barnes6cb2a212008-03-19 17:00:39 -07001002 /*
1003 * We have to order our ring_info tail store above and test
1004 * of the wait list below outside the wait lock. This is
1005 * like in wake_up_bit() where clearing a bit has to be
1006 * ordered with the unlocked test.
1007 */
1008 smp_mb();
1009
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 if (waitqueue_active(&ctx->wait))
1011 wake_up(&ctx->wait);
1012
Ken Chendee11c22007-02-03 01:13:45 -08001013 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 return ret;
1015}
1016
1017/* aio_read_evt
1018 * Pull an event off of the ioctx's event ring. Returns the number of
1019 * events fetched (0 or 1 ;-)
1020 * FIXME: make this use cmpxchg.
1021 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1022 */
1023static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1024{
1025 struct aio_ring_info *info = &ioctx->ring_info;
1026 struct aio_ring *ring;
1027 unsigned long head;
1028 int ret = 0;
1029
1030 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1031 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1032 (unsigned long)ring->head, (unsigned long)ring->tail,
1033 (unsigned long)ring->nr);
1034
1035 if (ring->head == ring->tail)
1036 goto out;
1037
1038 spin_lock(&info->ring_lock);
1039
1040 head = ring->head % info->nr;
1041 if (head != ring->tail) {
1042 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1043 *ent = *evp;
1044 head = (head + 1) % info->nr;
1045 smp_mb(); /* finish reading the event before updatng the head */
1046 ring->head = head;
1047 ret = 1;
1048 put_aio_ring_event(evp, KM_USER1);
1049 }
1050 spin_unlock(&info->ring_lock);
1051
1052out:
1053 kunmap_atomic(ring, KM_USER0);
1054 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1055 (unsigned long)ring->head, (unsigned long)ring->tail);
1056 return ret;
1057}
1058
1059struct aio_timeout {
1060 struct timer_list timer;
1061 int timed_out;
1062 struct task_struct *p;
1063};
1064
1065static void timeout_func(unsigned long data)
1066{
1067 struct aio_timeout *to = (struct aio_timeout *)data;
1068
1069 to->timed_out = 1;
1070 wake_up_process(to->p);
1071}
1072
1073static inline void init_timeout(struct aio_timeout *to)
1074{
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001075 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 to->timed_out = 0;
1077 to->p = current;
1078}
1079
1080static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1081 const struct timespec *ts)
1082{
1083 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1084 if (time_after(to->timer.expires, jiffies))
1085 add_timer(&to->timer);
1086 else
1087 to->timed_out = 1;
1088}
1089
1090static inline void clear_timeout(struct aio_timeout *to)
1091{
1092 del_singleshot_timer_sync(&to->timer);
1093}
1094
1095static int read_events(struct kioctx *ctx,
1096 long min_nr, long nr,
1097 struct io_event __user *event,
1098 struct timespec __user *timeout)
1099{
1100 long start_jiffies = jiffies;
1101 struct task_struct *tsk = current;
1102 DECLARE_WAITQUEUE(wait, tsk);
1103 int ret;
1104 int i = 0;
1105 struct io_event ent;
1106 struct aio_timeout to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 int retry = 0;
1108
1109 /* needed to zero any padding within an entry (there shouldn't be
1110 * any, but C is fun!
1111 */
1112 memset(&ent, 0, sizeof(ent));
1113retry:
1114 ret = 0;
1115 while (likely(i < nr)) {
1116 ret = aio_read_evt(ctx, &ent);
1117 if (unlikely(ret <= 0))
1118 break;
1119
1120 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1121 ent.data, ent.obj, ent.res, ent.res2);
1122
1123 /* Could we split the check in two? */
1124 ret = -EFAULT;
1125 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1126 dprintk("aio: lost an event due to EFAULT.\n");
1127 break;
1128 }
1129 ret = 0;
1130
1131 /* Good, event copied to userland, update counts. */
1132 event ++;
1133 i ++;
1134 }
1135
1136 if (min_nr <= i)
1137 return i;
1138 if (ret)
1139 return ret;
1140
1141 /* End fast path */
1142
1143 /* racey check, but it gets redone */
1144 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1145 retry = 1;
1146 aio_run_all_iocbs(ctx);
1147 goto retry;
1148 }
1149
1150 init_timeout(&to);
1151 if (timeout) {
1152 struct timespec ts;
1153 ret = -EFAULT;
1154 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1155 goto out;
1156
1157 set_timeout(start_jiffies, &to, &ts);
1158 }
1159
1160 while (likely(i < nr)) {
1161 add_wait_queue_exclusive(&ctx->wait, &wait);
1162 do {
1163 set_task_state(tsk, TASK_INTERRUPTIBLE);
1164 ret = aio_read_evt(ctx, &ent);
1165 if (ret)
1166 break;
1167 if (min_nr <= i)
1168 break;
Jeff Moyere92adcb2008-04-28 02:12:04 -07001169 if (unlikely(ctx->dead)) {
1170 ret = -EINVAL;
1171 break;
1172 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 if (to.timed_out) /* Only check after read evt */
1174 break;
Jeff Moyere00ba3d2007-12-04 23:45:02 -08001175 /* Try to only show up in io wait if there are ops
1176 * in flight */
1177 if (ctx->reqs_active)
1178 io_schedule();
1179 else
1180 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 if (signal_pending(tsk)) {
1182 ret = -EINTR;
1183 break;
1184 }
1185 /*ret = aio_read_evt(ctx, &ent);*/
1186 } while (1) ;
1187
1188 set_task_state(tsk, TASK_RUNNING);
1189 remove_wait_queue(&ctx->wait, &wait);
1190
1191 if (unlikely(ret <= 0))
1192 break;
1193
1194 ret = -EFAULT;
1195 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1196 dprintk("aio: lost an event due to EFAULT.\n");
1197 break;
1198 }
1199
1200 /* Good, event copied to userland, update counts. */
1201 event ++;
1202 i ++;
1203 }
1204
1205 if (timeout)
1206 clear_timeout(&to);
1207out:
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -07001208 destroy_timer_on_stack(&to.timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 return i ? i : ret;
1210}
1211
1212/* Take an ioctx and remove it from the list of ioctx's. Protects
1213 * against races with itself via ->dead.
1214 */
1215static void io_destroy(struct kioctx *ioctx)
1216{
1217 struct mm_struct *mm = current->mm;
1218 struct kioctx **tmp;
1219 int was_dead;
1220
1221 /* delete the entry from the list is someone else hasn't already */
1222 write_lock(&mm->ioctx_list_lock);
1223 was_dead = ioctx->dead;
1224 ioctx->dead = 1;
1225 for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx;
1226 tmp = &(*tmp)->next)
1227 ;
1228 if (*tmp)
1229 *tmp = ioctx->next;
1230 write_unlock(&mm->ioctx_list_lock);
1231
1232 dprintk("aio_release(%p)\n", ioctx);
1233 if (likely(!was_dead))
1234 put_ioctx(ioctx); /* twice for the list */
1235
1236 aio_cancel_all(ioctx);
1237 wait_for_all_aios(ioctx);
Jeff Moyere92adcb2008-04-28 02:12:04 -07001238
1239 /*
1240 * Wake up any waiters. The setting of ctx->dead must be seen
1241 * by other CPUs at this point. Right now, we rely on the
1242 * locking done by the above calls to ensure this consistency.
1243 */
1244 wake_up(&ioctx->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 put_ioctx(ioctx); /* once for the lookup */
1246}
1247
1248/* sys_io_setup:
1249 * Create an aio_context capable of receiving at least nr_events.
1250 * ctxp must not point to an aio_context that already exists, and
1251 * must be initialized to 0 prior to the call. On successful
1252 * creation of the aio_context, *ctxp is filled in with the resulting
1253 * handle. May fail with -EINVAL if *ctxp is not initialized,
1254 * if the specified nr_events exceeds internal limits. May fail
1255 * with -EAGAIN if the specified nr_events exceeds the user's limit
1256 * of available events. May fail with -ENOMEM if insufficient kernel
1257 * resources are available. May fail with -EFAULT if an invalid
1258 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1259 * implemented.
1260 */
1261asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp)
1262{
1263 struct kioctx *ioctx = NULL;
1264 unsigned long ctx;
1265 long ret;
1266
1267 ret = get_user(ctx, ctxp);
1268 if (unlikely(ret))
1269 goto out;
1270
1271 ret = -EINVAL;
Zach Brownd55b5fd2005-11-07 00:59:31 -08001272 if (unlikely(ctx || nr_events == 0)) {
1273 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1274 ctx, nr_events);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 goto out;
1276 }
1277
1278 ioctx = ioctx_alloc(nr_events);
1279 ret = PTR_ERR(ioctx);
1280 if (!IS_ERR(ioctx)) {
1281 ret = put_user(ioctx->user_id, ctxp);
1282 if (!ret)
1283 return 0;
1284
1285 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1286 io_destroy(ioctx);
1287 }
1288
1289out:
1290 return ret;
1291}
1292
1293/* sys_io_destroy:
1294 * Destroy the aio_context specified. May cancel any outstanding
1295 * AIOs and block on completion. Will fail with -ENOSYS if not
1296 * implemented. May fail with -EFAULT if the context pointed to
1297 * is invalid.
1298 */
1299asmlinkage long sys_io_destroy(aio_context_t ctx)
1300{
1301 struct kioctx *ioctx = lookup_ioctx(ctx);
1302 if (likely(NULL != ioctx)) {
1303 io_destroy(ioctx);
1304 return 0;
1305 }
1306 pr_debug("EINVAL: io_destroy: invalid context id\n");
1307 return -EINVAL;
1308}
1309
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001310static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1311{
1312 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1313
1314 BUG_ON(ret <= 0);
1315
1316 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1317 ssize_t this = min((ssize_t)iov->iov_len, ret);
1318 iov->iov_base += this;
1319 iov->iov_len -= this;
1320 iocb->ki_left -= this;
1321 ret -= this;
1322 if (iov->iov_len == 0) {
1323 iocb->ki_cur_seg++;
1324 iov++;
1325 }
1326 }
1327
1328 /* the caller should not have done more io than what fit in
1329 * the remaining iovecs */
1330 BUG_ON(ret > 0 && iocb->ki_left == 0);
1331}
1332
1333static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334{
1335 struct file *file = iocb->ki_filp;
1336 struct address_space *mapping = file->f_mapping;
1337 struct inode *inode = mapping->host;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001338 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1339 unsigned long, loff_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 ssize_t ret = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001341 unsigned short opcode;
1342
1343 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1344 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1345 rw_op = file->f_op->aio_read;
1346 opcode = IOCB_CMD_PREADV;
1347 } else {
1348 rw_op = file->f_op->aio_write;
1349 opcode = IOCB_CMD_PWRITEV;
1350 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351
Rusty Russellc2ec6682008-02-08 04:20:15 -08001352 /* This matches the pread()/pwrite() logic */
1353 if (iocb->ki_pos < 0)
1354 return -EINVAL;
1355
Zach Brown897f15f2005-09-30 11:58:55 -07001356 do {
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001357 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1358 iocb->ki_nr_segs - iocb->ki_cur_seg,
1359 iocb->ki_pos);
1360 if (ret > 0)
1361 aio_advance_iovec(iocb, ret);
Badari Pulavarty027445c2006-09-30 23:28:46 -07001362
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001363 /* retry all partial writes. retry partial reads as long as its a
1364 * regular file. */
Zach Brown353fb072005-09-30 11:58:56 -07001365 } while (ret > 0 && iocb->ki_left > 0 &&
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001366 (opcode == IOCB_CMD_PWRITEV ||
1367 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368
1369 /* This means we must have transferred all that we could */
1370 /* No need to retry anymore */
1371 if ((ret == 0) || (iocb->ki_left == 0))
1372 ret = iocb->ki_nbytes - iocb->ki_left;
1373
Rusty Russell7adfa2f2008-02-08 04:20:14 -08001374 /* If we managed to write some out we return that, rather than
1375 * the eventual error. */
1376 if (opcode == IOCB_CMD_PWRITEV
1377 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1378 && iocb->ki_nbytes - iocb->ki_left)
1379 ret = iocb->ki_nbytes - iocb->ki_left;
1380
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 return ret;
1382}
1383
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384static ssize_t aio_fdsync(struct kiocb *iocb)
1385{
1386 struct file *file = iocb->ki_filp;
1387 ssize_t ret = -EINVAL;
1388
1389 if (file->f_op->aio_fsync)
1390 ret = file->f_op->aio_fsync(iocb, 1);
1391 return ret;
1392}
1393
1394static ssize_t aio_fsync(struct kiocb *iocb)
1395{
1396 struct file *file = iocb->ki_filp;
1397 ssize_t ret = -EINVAL;
1398
1399 if (file->f_op->aio_fsync)
1400 ret = file->f_op->aio_fsync(iocb, 0);
1401 return ret;
1402}
1403
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001404static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb)
1405{
1406 ssize_t ret;
1407
1408 ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf,
1409 kiocb->ki_nbytes, 1,
1410 &kiocb->ki_inline_vec, &kiocb->ki_iovec);
1411 if (ret < 0)
1412 goto out;
1413
1414 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1415 kiocb->ki_cur_seg = 0;
1416 /* ki_nbytes/left now reflect bytes instead of segs */
1417 kiocb->ki_nbytes = ret;
1418 kiocb->ki_left = ret;
1419
1420 ret = 0;
1421out:
1422 return ret;
1423}
1424
1425static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1426{
1427 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1428 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1429 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1430 kiocb->ki_nr_segs = 1;
1431 kiocb->ki_cur_seg = 0;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001432 return 0;
1433}
1434
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435/*
1436 * aio_setup_iocb:
1437 * Performs the initial checks and aio retry method
1438 * setup for the kiocb at the time of io submission.
1439 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001440static ssize_t aio_setup_iocb(struct kiocb *kiocb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441{
1442 struct file *file = kiocb->ki_filp;
1443 ssize_t ret = 0;
1444
1445 switch (kiocb->ki_opcode) {
1446 case IOCB_CMD_PREAD:
1447 ret = -EBADF;
1448 if (unlikely(!(file->f_mode & FMODE_READ)))
1449 break;
1450 ret = -EFAULT;
1451 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1452 kiocb->ki_left)))
1453 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001454 ret = security_file_permission(file, MAY_READ);
1455 if (unlikely(ret))
1456 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001457 ret = aio_setup_single_vector(kiocb);
1458 if (ret)
1459 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 ret = -EINVAL;
1461 if (file->f_op->aio_read)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001462 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 break;
1464 case IOCB_CMD_PWRITE:
1465 ret = -EBADF;
1466 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1467 break;
1468 ret = -EFAULT;
1469 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1470 kiocb->ki_left)))
1471 break;
Kostik Belousov8766ce42005-10-23 12:57:13 -07001472 ret = security_file_permission(file, MAY_WRITE);
1473 if (unlikely(ret))
1474 break;
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001475 ret = aio_setup_single_vector(kiocb);
1476 if (ret)
1477 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 ret = -EINVAL;
1479 if (file->f_op->aio_write)
Badari Pulavartyeed4e512006-09-30 23:28:49 -07001480 kiocb->ki_retry = aio_rw_vect_retry;
1481 break;
1482 case IOCB_CMD_PREADV:
1483 ret = -EBADF;
1484 if (unlikely(!(file->f_mode & FMODE_READ)))
1485 break;
1486 ret = security_file_permission(file, MAY_READ);
1487 if (unlikely(ret))
1488 break;
1489 ret = aio_setup_vectored_rw(READ, kiocb);
1490 if (ret)
1491 break;
1492 ret = -EINVAL;
1493 if (file->f_op->aio_read)
1494 kiocb->ki_retry = aio_rw_vect_retry;
1495 break;
1496 case IOCB_CMD_PWRITEV:
1497 ret = -EBADF;
1498 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1499 break;
1500 ret = security_file_permission(file, MAY_WRITE);
1501 if (unlikely(ret))
1502 break;
1503 ret = aio_setup_vectored_rw(WRITE, kiocb);
1504 if (ret)
1505 break;
1506 ret = -EINVAL;
1507 if (file->f_op->aio_write)
1508 kiocb->ki_retry = aio_rw_vect_retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509 break;
1510 case IOCB_CMD_FDSYNC:
1511 ret = -EINVAL;
1512 if (file->f_op->aio_fsync)
1513 kiocb->ki_retry = aio_fdsync;
1514 break;
1515 case IOCB_CMD_FSYNC:
1516 ret = -EINVAL;
1517 if (file->f_op->aio_fsync)
1518 kiocb->ki_retry = aio_fsync;
1519 break;
1520 default:
1521 dprintk("EINVAL: io_submit: no operation provided\n");
1522 ret = -EINVAL;
1523 }
1524
1525 if (!kiocb->ki_retry)
1526 return ret;
1527
1528 return 0;
1529}
1530
1531/*
1532 * aio_wake_function:
1533 * wait queue callback function for aio notification,
1534 * Simply triggers a retry of the operation via kick_iocb.
1535 *
1536 * This callback is specified in the wait queue entry in
Alexey Dobriyan6212e3a2007-10-18 03:04:56 -07001537 * a kiocb.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 *
1539 * Note:
1540 * This routine is executed with the wait queue lock held.
1541 * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
1542 * the ioctx lock inside the wait queue lock. This is safe
1543 * because this callback isn't used for wait queues which
1544 * are nested inside ioctx lock (i.e. ctx->wait)
1545 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001546static int aio_wake_function(wait_queue_t *wait, unsigned mode,
1547 int sync, void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548{
1549 struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
1550
1551 list_del_init(&wait->task_list);
1552 kick_iocb(iocb);
1553 return 1;
1554}
1555
Adrian Bunkd5470b52008-04-29 00:58:57 -07001556static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 struct iocb *iocb)
1558{
1559 struct kiocb *req;
1560 struct file *file;
1561 ssize_t ret;
1562
1563 /* enforce forwards compatibility on users */
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001564 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 pr_debug("EINVAL: io_submit: reserve field set\n");
1566 return -EINVAL;
1567 }
1568
1569 /* prevent overflows */
1570 if (unlikely(
1571 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1572 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1573 ((ssize_t)iocb->aio_nbytes < 0)
1574 )) {
1575 pr_debug("EINVAL: io_submit: overflow check\n");
1576 return -EINVAL;
1577 }
1578
1579 file = fget(iocb->aio_fildes);
1580 if (unlikely(!file))
1581 return -EBADF;
1582
1583 req = aio_get_req(ctx); /* returns with 2 references to req */
1584 if (unlikely(!req)) {
1585 fput(file);
1586 return -EAGAIN;
1587 }
Yan Zheng87e28312007-10-08 12:16:20 -07001588 req->ki_filp = file;
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001589 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1590 /*
1591 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1592 * instance of the file* now. The file descriptor must be
1593 * an eventfd() fd, and will be signaled for each completed
1594 * event using the eventfd_signal() function.
1595 */
1596 req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -07001597 if (IS_ERR(req->ki_eventfd)) {
Davide Libenzi9c3060b2007-05-10 22:23:21 -07001598 ret = PTR_ERR(req->ki_eventfd);
1599 goto out_put_req;
1600 }
1601 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001602
Ken Chen212079c2005-05-01 08:59:15 -07001603 ret = put_user(req->ki_key, &user_iocb->aio_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604 if (unlikely(ret)) {
1605 dprintk("EFAULT: aio_key\n");
1606 goto out_put_req;
1607 }
1608
1609 req->ki_obj.user = user_iocb;
1610 req->ki_user_data = iocb->aio_data;
1611 req->ki_pos = iocb->aio_offset;
1612
1613 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1614 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1615 req->ki_opcode = iocb->aio_lio_opcode;
1616 init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
1617 INIT_LIST_HEAD(&req->ki_wait.task_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618
1619 ret = aio_setup_iocb(req);
1620
1621 if (ret)
1622 goto out_put_req;
1623
1624 spin_lock_irq(&ctx->ctx_lock);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001625 aio_run_iocb(req);
Benjamin LaHaiseac0b1bc2005-09-09 13:02:09 -07001626 if (!list_empty(&ctx->run_list)) {
Ken Chen954d3e92005-05-01 08:59:16 -07001627 /* drain the run list */
1628 while (__aio_run_iocbs(ctx))
1629 ;
1630 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 spin_unlock_irq(&ctx->ctx_lock);
1632 aio_put_req(req); /* drop extra ref to req */
1633 return 0;
1634
1635out_put_req:
1636 aio_put_req(req); /* drop extra ref to req */
1637 aio_put_req(req); /* drop i/o ref to req */
1638 return ret;
1639}
1640
1641/* sys_io_submit:
1642 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1643 * the number of iocbs queued. May return -EINVAL if the aio_context
1644 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1645 * *iocbpp[0] is not properly initialized, if the operation specified
1646 * is invalid for the file descriptor in the iocb. May fail with
1647 * -EFAULT if any of the data structures point to invalid data. May
1648 * fail with -EBADF if the file descriptor specified in the first
1649 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1650 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1651 * fail with -ENOSYS if not implemented.
1652 */
1653asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
1654 struct iocb __user * __user *iocbpp)
1655{
1656 struct kioctx *ctx;
1657 long ret = 0;
1658 int i;
1659
1660 if (unlikely(nr < 0))
1661 return -EINVAL;
1662
1663 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1664 return -EFAULT;
1665
1666 ctx = lookup_ioctx(ctx_id);
1667 if (unlikely(!ctx)) {
1668 pr_debug("EINVAL: io_submit: invalid context id\n");
1669 return -EINVAL;
1670 }
1671
1672 /*
1673 * AKPM: should this return a partial result if some of the IOs were
1674 * successfully submitted?
1675 */
1676 for (i=0; i<nr; i++) {
1677 struct iocb __user *user_iocb;
1678 struct iocb tmp;
1679
1680 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1681 ret = -EFAULT;
1682 break;
1683 }
1684
1685 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1686 ret = -EFAULT;
1687 break;
1688 }
1689
1690 ret = io_submit_one(ctx, user_iocb, &tmp);
1691 if (ret)
1692 break;
1693 }
1694
1695 put_ioctx(ctx);
1696 return i ? i : ret;
1697}
1698
1699/* lookup_kiocb
1700 * Finds a given iocb for cancellation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 */
Adrian Bunk25ee7e32005-04-25 08:18:14 -07001702static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1703 u32 key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704{
1705 struct list_head *pos;
Zach Brownd00689a2005-11-13 16:07:34 -08001706
1707 assert_spin_locked(&ctx->ctx_lock);
1708
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 /* TODO: use a hash or array, this sucks. */
1710 list_for_each(pos, &ctx->active_reqs) {
1711 struct kiocb *kiocb = list_kiocb(pos);
1712 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1713 return kiocb;
1714 }
1715 return NULL;
1716}
1717
1718/* sys_io_cancel:
1719 * Attempts to cancel an iocb previously passed to io_submit. If
1720 * the operation is successfully cancelled, the resulting event is
1721 * copied into the memory pointed to by result without being placed
1722 * into the completion queue and 0 is returned. May fail with
1723 * -EFAULT if any of the data structures pointed to are invalid.
1724 * May fail with -EINVAL if aio_context specified by ctx_id is
1725 * invalid. May fail with -EAGAIN if the iocb specified was not
1726 * cancelled. Will fail with -ENOSYS if not implemented.
1727 */
1728asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
1729 struct io_event __user *result)
1730{
1731 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1732 struct kioctx *ctx;
1733 struct kiocb *kiocb;
1734 u32 key;
1735 int ret;
1736
1737 ret = get_user(key, &iocb->aio_key);
1738 if (unlikely(ret))
1739 return -EFAULT;
1740
1741 ctx = lookup_ioctx(ctx_id);
1742 if (unlikely(!ctx))
1743 return -EINVAL;
1744
1745 spin_lock_irq(&ctx->ctx_lock);
1746 ret = -EAGAIN;
1747 kiocb = lookup_kiocb(ctx, iocb, key);
1748 if (kiocb && kiocb->ki_cancel) {
1749 cancel = kiocb->ki_cancel;
1750 kiocb->ki_users ++;
1751 kiocbSetCancelled(kiocb);
1752 } else
1753 cancel = NULL;
1754 spin_unlock_irq(&ctx->ctx_lock);
1755
1756 if (NULL != cancel) {
1757 struct io_event tmp;
1758 pr_debug("calling cancel\n");
1759 memset(&tmp, 0, sizeof(tmp));
1760 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1761 tmp.data = kiocb->ki_user_data;
1762 ret = cancel(kiocb, &tmp);
1763 if (!ret) {
1764 /* Cancellation succeeded -- copy the result
1765 * into the user's buffer.
1766 */
1767 if (copy_to_user(result, &tmp, sizeof(tmp)))
1768 ret = -EFAULT;
1769 }
1770 } else
Wendy Cheng8f582022005-09-09 13:02:08 -07001771 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772
1773 put_ioctx(ctx);
1774
1775 return ret;
1776}
1777
1778/* io_getevents:
1779 * Attempts to read at least min_nr events and up to nr events from
1780 * the completion queue for the aio_context specified by ctx_id. May
1781 * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
1782 * if nr is out of range, if when is out of range. May fail with
1783 * -EFAULT if any of the memory specified to is invalid. May return
1784 * 0 or < min_nr if no events are available and the timeout specified
1785 * by when has elapsed, where when == NULL specifies an infinite
1786 * timeout. Note that the timeout pointed to by when is relative and
1787 * will be updated if not NULL and the operation blocks. Will fail
1788 * with -ENOSYS if not implemented.
1789 */
1790asmlinkage long sys_io_getevents(aio_context_t ctx_id,
1791 long min_nr,
1792 long nr,
1793 struct io_event __user *events,
1794 struct timespec __user *timeout)
1795{
1796 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1797 long ret = -EINVAL;
1798
1799 if (likely(ioctx)) {
1800 if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0))
1801 ret = read_events(ioctx, min_nr, nr, events, timeout);
1802 put_ioctx(ioctx);
1803 }
1804
Roland McGrath598af052008-04-10 15:38:45 -07001805 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806 return ret;
1807}
1808
1809__initcall(aio_setup);
1810
1811EXPORT_SYMBOL(aio_complete);
1812EXPORT_SYMBOL(aio_put_req);
1813EXPORT_SYMBOL(wait_on_sync_kiocb);