Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
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 | */ | |
caf4167a KO |
11 | #define pr_fmt(fmt) "%s: " fmt, __func__ |
12 | ||
1da177e4 LT |
13 | #include <linux/kernel.h> |
14 | #include <linux/init.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/time.h> | |
17 | #include <linux/aio_abi.h> | |
630d9c47 | 18 | #include <linux/export.h> |
1da177e4 | 19 | #include <linux/syscalls.h> |
b9d128f1 | 20 | #include <linux/backing-dev.h> |
027445c3 | 21 | #include <linux/uio.h> |
1da177e4 | 22 | |
1da177e4 LT |
23 | #include <linux/sched.h> |
24 | #include <linux/fs.h> | |
25 | #include <linux/file.h> | |
26 | #include <linux/mm.h> | |
27 | #include <linux/mman.h> | |
3d2d827f | 28 | #include <linux/mmu_context.h> |
e1bdd5f2 | 29 | #include <linux/percpu.h> |
1da177e4 LT |
30 | #include <linux/slab.h> |
31 | #include <linux/timer.h> | |
32 | #include <linux/aio.h> | |
33 | #include <linux/highmem.h> | |
34 | #include <linux/workqueue.h> | |
35 | #include <linux/security.h> | |
9c3060be | 36 | #include <linux/eventfd.h> |
cfb1e33e | 37 | #include <linux/blkdev.h> |
9d85cba7 | 38 | #include <linux/compat.h> |
36bc08cc GZ |
39 | #include <linux/anon_inodes.h> |
40 | #include <linux/migrate.h> | |
41 | #include <linux/ramfs.h> | |
723be6e3 | 42 | #include <linux/percpu-refcount.h> |
1da177e4 LT |
43 | |
44 | #include <asm/kmap_types.h> | |
45 | #include <asm/uaccess.h> | |
1da177e4 | 46 | |
68d70d03 AV |
47 | #include "internal.h" |
48 | ||
4e179bca KO |
49 | #define AIO_RING_MAGIC 0xa10a10a1 |
50 | #define AIO_RING_COMPAT_FEATURES 1 | |
51 | #define AIO_RING_INCOMPAT_FEATURES 0 | |
52 | struct aio_ring { | |
53 | unsigned id; /* kernel internal index number */ | |
54 | unsigned nr; /* number of io_events */ | |
55 | unsigned head; | |
56 | unsigned tail; | |
57 | ||
58 | unsigned magic; | |
59 | unsigned compat_features; | |
60 | unsigned incompat_features; | |
61 | unsigned header_length; /* size of aio_ring */ | |
62 | ||
63 | ||
64 | struct io_event io_events[0]; | |
65 | }; /* 128 bytes + ring size */ | |
66 | ||
67 | #define AIO_RING_PAGES 8 | |
4e179bca | 68 | |
db446a08 BL |
69 | struct kioctx_table { |
70 | struct rcu_head rcu; | |
71 | unsigned nr; | |
72 | struct kioctx *table[]; | |
73 | }; | |
74 | ||
e1bdd5f2 KO |
75 | struct kioctx_cpu { |
76 | unsigned reqs_available; | |
77 | }; | |
78 | ||
4e179bca | 79 | struct kioctx { |
723be6e3 | 80 | struct percpu_ref users; |
36f55889 | 81 | atomic_t dead; |
4e179bca | 82 | |
4e179bca | 83 | unsigned long user_id; |
4e179bca | 84 | |
e1bdd5f2 KO |
85 | struct __percpu kioctx_cpu *cpu; |
86 | ||
87 | /* | |
88 | * For percpu reqs_available, number of slots we move to/from global | |
89 | * counter at a time: | |
90 | */ | |
91 | unsigned req_batch; | |
3e845ce0 KO |
92 | /* |
93 | * This is what userspace passed to io_setup(), it's not used for | |
94 | * anything but counting against the global max_reqs quota. | |
95 | * | |
58c85dc2 | 96 | * The real limit is nr_events - 1, which will be larger (see |
3e845ce0 KO |
97 | * aio_setup_ring()) |
98 | */ | |
4e179bca KO |
99 | unsigned max_reqs; |
100 | ||
58c85dc2 KO |
101 | /* Size of ringbuffer, in units of struct io_event */ |
102 | unsigned nr_events; | |
4e179bca | 103 | |
58c85dc2 KO |
104 | unsigned long mmap_base; |
105 | unsigned long mmap_size; | |
106 | ||
107 | struct page **ring_pages; | |
108 | long nr_pages; | |
109 | ||
4e23bcae | 110 | struct rcu_head rcu_head; |
723be6e3 | 111 | struct work_struct free_work; |
4e23bcae KO |
112 | |
113 | struct { | |
34e83fc6 KO |
114 | /* |
115 | * This counts the number of available slots in the ringbuffer, | |
116 | * so we avoid overflowing it: it's decremented (if positive) | |
117 | * when allocating a kiocb and incremented when the resulting | |
118 | * io_event is pulled off the ringbuffer. | |
e1bdd5f2 KO |
119 | * |
120 | * We batch accesses to it with a percpu version. | |
34e83fc6 KO |
121 | */ |
122 | atomic_t reqs_available; | |
4e23bcae KO |
123 | } ____cacheline_aligned_in_smp; |
124 | ||
125 | struct { | |
126 | spinlock_t ctx_lock; | |
127 | struct list_head active_reqs; /* used for cancellation */ | |
128 | } ____cacheline_aligned_in_smp; | |
129 | ||
58c85dc2 KO |
130 | struct { |
131 | struct mutex ring_lock; | |
4e23bcae KO |
132 | wait_queue_head_t wait; |
133 | } ____cacheline_aligned_in_smp; | |
58c85dc2 KO |
134 | |
135 | struct { | |
136 | unsigned tail; | |
137 | spinlock_t completion_lock; | |
4e23bcae | 138 | } ____cacheline_aligned_in_smp; |
58c85dc2 KO |
139 | |
140 | struct page *internal_pages[AIO_RING_PAGES]; | |
36bc08cc | 141 | struct file *aio_ring_file; |
db446a08 BL |
142 | |
143 | unsigned id; | |
4e179bca KO |
144 | }; |
145 | ||
1da177e4 | 146 | /*------ sysctl variables----*/ |
d55b5fda ZB |
147 | static DEFINE_SPINLOCK(aio_nr_lock); |
148 | unsigned long aio_nr; /* current system wide number of aio requests */ | |
149 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ | |
1da177e4 LT |
150 | /*----end sysctl variables---*/ |
151 | ||
e18b890b CL |
152 | static struct kmem_cache *kiocb_cachep; |
153 | static struct kmem_cache *kioctx_cachep; | |
1da177e4 | 154 | |
1da177e4 LT |
155 | /* aio_setup |
156 | * Creates the slab caches used by the aio routines, panic on | |
157 | * failure as this is done early during the boot sequence. | |
158 | */ | |
159 | static int __init aio_setup(void) | |
160 | { | |
0a31bd5f CL |
161 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
162 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); | |
1da177e4 | 163 | |
caf4167a | 164 | pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page)); |
1da177e4 LT |
165 | |
166 | return 0; | |
167 | } | |
385773e0 | 168 | __initcall(aio_setup); |
1da177e4 LT |
169 | |
170 | static void aio_free_ring(struct kioctx *ctx) | |
171 | { | |
36bc08cc GZ |
172 | int i; |
173 | struct file *aio_ring_file = ctx->aio_ring_file; | |
1da177e4 | 174 | |
36bc08cc GZ |
175 | for (i = 0; i < ctx->nr_pages; i++) { |
176 | pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, | |
177 | page_count(ctx->ring_pages[i])); | |
58c85dc2 | 178 | put_page(ctx->ring_pages[i]); |
36bc08cc | 179 | } |
1da177e4 | 180 | |
58c85dc2 KO |
181 | if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) |
182 | kfree(ctx->ring_pages); | |
36bc08cc GZ |
183 | |
184 | if (aio_ring_file) { | |
185 | truncate_setsize(aio_ring_file->f_inode, 0); | |
186 | pr_debug("pid(%d) i_nlink=%u d_count=%d d_unhashed=%d i_count=%d\n", | |
187 | current->pid, aio_ring_file->f_inode->i_nlink, | |
188 | aio_ring_file->f_path.dentry->d_count, | |
189 | d_unhashed(aio_ring_file->f_path.dentry), | |
190 | atomic_read(&aio_ring_file->f_inode->i_count)); | |
191 | fput(aio_ring_file); | |
192 | ctx->aio_ring_file = NULL; | |
193 | } | |
194 | } | |
195 | ||
196 | static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) | |
197 | { | |
198 | vma->vm_ops = &generic_file_vm_ops; | |
199 | return 0; | |
200 | } | |
201 | ||
202 | static const struct file_operations aio_ring_fops = { | |
203 | .mmap = aio_ring_mmap, | |
204 | }; | |
205 | ||
206 | static int aio_set_page_dirty(struct page *page) | |
207 | { | |
208 | return 0; | |
209 | } | |
210 | ||
0c45355f | 211 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc GZ |
212 | static int aio_migratepage(struct address_space *mapping, struct page *new, |
213 | struct page *old, enum migrate_mode mode) | |
214 | { | |
215 | struct kioctx *ctx = mapping->private_data; | |
216 | unsigned long flags; | |
217 | unsigned idx = old->index; | |
218 | int rc; | |
219 | ||
220 | /* Writeback must be complete */ | |
221 | BUG_ON(PageWriteback(old)); | |
222 | put_page(old); | |
223 | ||
224 | rc = migrate_page_move_mapping(mapping, new, old, NULL, mode); | |
225 | if (rc != MIGRATEPAGE_SUCCESS) { | |
226 | get_page(old); | |
227 | return rc; | |
228 | } | |
229 | ||
230 | get_page(new); | |
231 | ||
232 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
233 | migrate_page_copy(new, old); | |
234 | ctx->ring_pages[idx] = new; | |
235 | spin_unlock_irqrestore(&ctx->completion_lock, flags); | |
236 | ||
237 | return rc; | |
1da177e4 | 238 | } |
0c45355f | 239 | #endif |
1da177e4 | 240 | |
36bc08cc GZ |
241 | static const struct address_space_operations aio_ctx_aops = { |
242 | .set_page_dirty = aio_set_page_dirty, | |
0c45355f | 243 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc | 244 | .migratepage = aio_migratepage, |
0c45355f | 245 | #endif |
36bc08cc GZ |
246 | }; |
247 | ||
1da177e4 LT |
248 | static int aio_setup_ring(struct kioctx *ctx) |
249 | { | |
250 | struct aio_ring *ring; | |
1da177e4 | 251 | unsigned nr_events = ctx->max_reqs; |
41003a7b | 252 | struct mm_struct *mm = current->mm; |
41badc15 | 253 | unsigned long size, populate; |
1da177e4 | 254 | int nr_pages; |
36bc08cc GZ |
255 | int i; |
256 | struct file *file; | |
1da177e4 LT |
257 | |
258 | /* Compensate for the ring buffer's head/tail overlap entry */ | |
259 | nr_events += 2; /* 1 is required, 2 for good luck */ | |
260 | ||
261 | size = sizeof(struct aio_ring); | |
262 | size += sizeof(struct io_event) * nr_events; | |
1da177e4 | 263 | |
36bc08cc | 264 | nr_pages = PFN_UP(size); |
1da177e4 LT |
265 | if (nr_pages < 0) |
266 | return -EINVAL; | |
267 | ||
36bc08cc GZ |
268 | file = anon_inode_getfile_private("[aio]", &aio_ring_fops, ctx, O_RDWR); |
269 | if (IS_ERR(file)) { | |
270 | ctx->aio_ring_file = NULL; | |
271 | return -EAGAIN; | |
272 | } | |
273 | ||
274 | file->f_inode->i_mapping->a_ops = &aio_ctx_aops; | |
275 | file->f_inode->i_mapping->private_data = ctx; | |
276 | file->f_inode->i_size = PAGE_SIZE * (loff_t)nr_pages; | |
277 | ||
278 | for (i = 0; i < nr_pages; i++) { | |
279 | struct page *page; | |
280 | page = find_or_create_page(file->f_inode->i_mapping, | |
281 | i, GFP_HIGHUSER | __GFP_ZERO); | |
282 | if (!page) | |
283 | break; | |
284 | pr_debug("pid(%d) page[%d]->count=%d\n", | |
285 | current->pid, i, page_count(page)); | |
286 | SetPageUptodate(page); | |
287 | SetPageDirty(page); | |
288 | unlock_page(page); | |
289 | } | |
290 | ctx->aio_ring_file = file; | |
291 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) | |
292 | / sizeof(struct io_event); | |
1da177e4 | 293 | |
58c85dc2 | 294 | ctx->ring_pages = ctx->internal_pages; |
1da177e4 | 295 | if (nr_pages > AIO_RING_PAGES) { |
58c85dc2 KO |
296 | ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), |
297 | GFP_KERNEL); | |
298 | if (!ctx->ring_pages) | |
1da177e4 | 299 | return -ENOMEM; |
1da177e4 LT |
300 | } |
301 | ||
58c85dc2 KO |
302 | ctx->mmap_size = nr_pages * PAGE_SIZE; |
303 | pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); | |
36bc08cc | 304 | |
41003a7b | 305 | down_write(&mm->mmap_sem); |
36bc08cc GZ |
306 | ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, |
307 | PROT_READ | PROT_WRITE, | |
308 | MAP_SHARED | MAP_POPULATE, 0, &populate); | |
58c85dc2 | 309 | if (IS_ERR((void *)ctx->mmap_base)) { |
41003a7b | 310 | up_write(&mm->mmap_sem); |
58c85dc2 | 311 | ctx->mmap_size = 0; |
1da177e4 LT |
312 | aio_free_ring(ctx); |
313 | return -EAGAIN; | |
314 | } | |
36bc08cc GZ |
315 | up_write(&mm->mmap_sem); |
316 | ||
317 | mm_populate(ctx->mmap_base, populate); | |
1da177e4 | 318 | |
58c85dc2 KO |
319 | pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); |
320 | ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages, | |
321 | 1, 0, ctx->ring_pages, NULL); | |
36bc08cc GZ |
322 | for (i = 0; i < ctx->nr_pages; i++) |
323 | put_page(ctx->ring_pages[i]); | |
1da177e4 | 324 | |
58c85dc2 | 325 | if (unlikely(ctx->nr_pages != nr_pages)) { |
1da177e4 LT |
326 | aio_free_ring(ctx); |
327 | return -EAGAIN; | |
328 | } | |
329 | ||
58c85dc2 KO |
330 | ctx->user_id = ctx->mmap_base; |
331 | ctx->nr_events = nr_events; /* trusted copy */ | |
1da177e4 | 332 | |
58c85dc2 | 333 | ring = kmap_atomic(ctx->ring_pages[0]); |
1da177e4 | 334 | ring->nr = nr_events; /* user copy */ |
db446a08 | 335 | ring->id = ~0U; |
1da177e4 LT |
336 | ring->head = ring->tail = 0; |
337 | ring->magic = AIO_RING_MAGIC; | |
338 | ring->compat_features = AIO_RING_COMPAT_FEATURES; | |
339 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; | |
340 | ring->header_length = sizeof(struct aio_ring); | |
e8e3c3d6 | 341 | kunmap_atomic(ring); |
58c85dc2 | 342 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 LT |
343 | |
344 | return 0; | |
345 | } | |
346 | ||
1da177e4 LT |
347 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
348 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) | |
349 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) | |
350 | ||
0460fef2 KO |
351 | void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel) |
352 | { | |
353 | struct kioctx *ctx = req->ki_ctx; | |
354 | unsigned long flags; | |
355 | ||
356 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
357 | ||
358 | if (!req->ki_list.next) | |
359 | list_add(&req->ki_list, &ctx->active_reqs); | |
360 | ||
361 | req->ki_cancel = cancel; | |
362 | ||
363 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
364 | } | |
365 | EXPORT_SYMBOL(kiocb_set_cancel_fn); | |
366 | ||
bec68faa | 367 | static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb) |
906b973c | 368 | { |
0460fef2 | 369 | kiocb_cancel_fn *old, *cancel; |
906b973c | 370 | |
0460fef2 KO |
371 | /* |
372 | * Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it | |
373 | * actually has a cancel function, hence the cmpxchg() | |
374 | */ | |
375 | ||
376 | cancel = ACCESS_ONCE(kiocb->ki_cancel); | |
377 | do { | |
378 | if (!cancel || cancel == KIOCB_CANCELLED) | |
57282d8f | 379 | return -EINVAL; |
906b973c | 380 | |
0460fef2 KO |
381 | old = cancel; |
382 | cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED); | |
383 | } while (cancel != old); | |
906b973c | 384 | |
57282d8f | 385 | return cancel(kiocb); |
906b973c KO |
386 | } |
387 | ||
36f55889 KO |
388 | static void free_ioctx_rcu(struct rcu_head *head) |
389 | { | |
390 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); | |
e1bdd5f2 KO |
391 | |
392 | free_percpu(ctx->cpu); | |
36f55889 KO |
393 | kmem_cache_free(kioctx_cachep, ctx); |
394 | } | |
395 | ||
396 | /* | |
397 | * When this function runs, the kioctx has been removed from the "hash table" | |
398 | * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - | |
399 | * now it's safe to cancel any that need to be. | |
400 | */ | |
723be6e3 | 401 | static void free_ioctx(struct work_struct *work) |
36f55889 | 402 | { |
723be6e3 | 403 | struct kioctx *ctx = container_of(work, struct kioctx, free_work); |
3e845ce0 | 404 | struct aio_ring *ring; |
36f55889 | 405 | struct kiocb *req; |
5ffac122 KO |
406 | unsigned cpu, avail; |
407 | DEFINE_WAIT(wait); | |
36f55889 KO |
408 | |
409 | spin_lock_irq(&ctx->ctx_lock); | |
410 | ||
411 | while (!list_empty(&ctx->active_reqs)) { | |
412 | req = list_first_entry(&ctx->active_reqs, | |
413 | struct kiocb, ki_list); | |
414 | ||
415 | list_del_init(&req->ki_list); | |
bec68faa | 416 | kiocb_cancel(ctx, req); |
36f55889 KO |
417 | } |
418 | ||
419 | spin_unlock_irq(&ctx->ctx_lock); | |
420 | ||
e1bdd5f2 KO |
421 | for_each_possible_cpu(cpu) { |
422 | struct kioctx_cpu *kcpu = per_cpu_ptr(ctx->cpu, cpu); | |
423 | ||
424 | atomic_add(kcpu->reqs_available, &ctx->reqs_available); | |
425 | kcpu->reqs_available = 0; | |
426 | } | |
427 | ||
5ffac122 KO |
428 | while (1) { |
429 | prepare_to_wait(&ctx->wait, &wait, TASK_UNINTERRUPTIBLE); | |
3e845ce0 | 430 | |
5ffac122 KO |
431 | ring = kmap_atomic(ctx->ring_pages[0]); |
432 | avail = (ring->head <= ring->tail) | |
433 | ? ring->tail - ring->head | |
434 | : ctx->nr_events - ring->head + ring->tail; | |
3e845ce0 | 435 | |
34e83fc6 | 436 | atomic_add(avail, &ctx->reqs_available); |
5ffac122 KO |
437 | ring->head = ring->tail; |
438 | kunmap_atomic(ring); | |
439 | ||
440 | if (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1) | |
441 | break; | |
442 | ||
443 | schedule(); | |
3e845ce0 | 444 | } |
5ffac122 | 445 | finish_wait(&ctx->wait, &wait); |
3e845ce0 | 446 | |
34e83fc6 | 447 | WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr_events - 1); |
36f55889 KO |
448 | |
449 | aio_free_ring(ctx); | |
450 | ||
36f55889 KO |
451 | pr_debug("freeing %p\n", ctx); |
452 | ||
453 | /* | |
454 | * Here the call_rcu() is between the wait_event() for reqs_active to | |
455 | * hit 0, and freeing the ioctx. | |
456 | * | |
457 | * aio_complete() decrements reqs_active, but it has to touch the ioctx | |
458 | * after to issue a wakeup so we use rcu. | |
459 | */ | |
460 | call_rcu(&ctx->rcu_head, free_ioctx_rcu); | |
461 | } | |
462 | ||
723be6e3 | 463 | static void free_ioctx_ref(struct percpu_ref *ref) |
36f55889 | 464 | { |
723be6e3 KO |
465 | struct kioctx *ctx = container_of(ref, struct kioctx, users); |
466 | ||
467 | INIT_WORK(&ctx->free_work, free_ioctx); | |
468 | schedule_work(&ctx->free_work); | |
36f55889 KO |
469 | } |
470 | ||
db446a08 BL |
471 | static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) |
472 | { | |
473 | unsigned i, new_nr; | |
474 | struct kioctx_table *table, *old; | |
475 | struct aio_ring *ring; | |
476 | ||
477 | spin_lock(&mm->ioctx_lock); | |
478 | table = rcu_dereference(mm->ioctx_table); | |
479 | ||
480 | while (1) { | |
481 | if (table) | |
482 | for (i = 0; i < table->nr; i++) | |
483 | if (!table->table[i]) { | |
484 | ctx->id = i; | |
485 | table->table[i] = ctx; | |
486 | spin_unlock(&mm->ioctx_lock); | |
487 | ||
488 | ring = kmap_atomic(ctx->ring_pages[0]); | |
489 | ring->id = ctx->id; | |
490 | kunmap_atomic(ring); | |
491 | return 0; | |
492 | } | |
493 | ||
494 | new_nr = (table ? table->nr : 1) * 4; | |
495 | ||
496 | spin_unlock(&mm->ioctx_lock); | |
497 | ||
498 | table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * | |
499 | new_nr, GFP_KERNEL); | |
500 | if (!table) | |
501 | return -ENOMEM; | |
502 | ||
503 | table->nr = new_nr; | |
504 | ||
505 | spin_lock(&mm->ioctx_lock); | |
506 | old = rcu_dereference(mm->ioctx_table); | |
507 | ||
508 | if (!old) { | |
509 | rcu_assign_pointer(mm->ioctx_table, table); | |
510 | } else if (table->nr > old->nr) { | |
511 | memcpy(table->table, old->table, | |
512 | old->nr * sizeof(struct kioctx *)); | |
513 | ||
514 | rcu_assign_pointer(mm->ioctx_table, table); | |
515 | kfree_rcu(old, rcu); | |
516 | } else { | |
517 | kfree(table); | |
518 | table = old; | |
519 | } | |
520 | } | |
521 | } | |
522 | ||
1da177e4 LT |
523 | /* ioctx_alloc |
524 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. | |
525 | */ | |
526 | static struct kioctx *ioctx_alloc(unsigned nr_events) | |
527 | { | |
41003a7b | 528 | struct mm_struct *mm = current->mm; |
1da177e4 | 529 | struct kioctx *ctx; |
e23754f8 | 530 | int err = -ENOMEM; |
1da177e4 | 531 | |
e1bdd5f2 KO |
532 | /* |
533 | * We keep track of the number of available ringbuffer slots, to prevent | |
534 | * overflow (reqs_available), and we also use percpu counters for this. | |
535 | * | |
536 | * So since up to half the slots might be on other cpu's percpu counters | |
537 | * and unavailable, double nr_events so userspace sees what they | |
538 | * expected: additionally, we move req_batch slots to/from percpu | |
539 | * counters at a time, so make sure that isn't 0: | |
540 | */ | |
541 | nr_events = max(nr_events, num_possible_cpus() * 4); | |
542 | nr_events *= 2; | |
543 | ||
1da177e4 LT |
544 | /* Prevent overflows */ |
545 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || | |
546 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { | |
547 | pr_debug("ENOMEM: nr_events too high\n"); | |
548 | return ERR_PTR(-EINVAL); | |
549 | } | |
550 | ||
4cd81c3d | 551 | if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL)) |
1da177e4 LT |
552 | return ERR_PTR(-EAGAIN); |
553 | ||
c3762229 | 554 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
1da177e4 LT |
555 | if (!ctx) |
556 | return ERR_PTR(-ENOMEM); | |
557 | ||
1da177e4 | 558 | ctx->max_reqs = nr_events; |
1da177e4 | 559 | |
723be6e3 KO |
560 | if (percpu_ref_init(&ctx->users, free_ioctx_ref)) |
561 | goto out_freectx; | |
562 | ||
1da177e4 | 563 | spin_lock_init(&ctx->ctx_lock); |
0460fef2 | 564 | spin_lock_init(&ctx->completion_lock); |
58c85dc2 | 565 | mutex_init(&ctx->ring_lock); |
1da177e4 LT |
566 | init_waitqueue_head(&ctx->wait); |
567 | ||
568 | INIT_LIST_HEAD(&ctx->active_reqs); | |
1da177e4 | 569 | |
e1bdd5f2 KO |
570 | ctx->cpu = alloc_percpu(struct kioctx_cpu); |
571 | if (!ctx->cpu) | |
723be6e3 | 572 | goto out_freeref; |
1da177e4 | 573 | |
e1bdd5f2 KO |
574 | if (aio_setup_ring(ctx) < 0) |
575 | goto out_freepcpu; | |
576 | ||
34e83fc6 | 577 | atomic_set(&ctx->reqs_available, ctx->nr_events - 1); |
e1bdd5f2 KO |
578 | ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); |
579 | BUG_ON(!ctx->req_batch); | |
34e83fc6 | 580 | |
db446a08 BL |
581 | err = ioctx_add_table(ctx, mm); |
582 | if (err) | |
583 | goto out_cleanup_noerr; | |
584 | ||
1da177e4 | 585 | /* limit the number of system wide aios */ |
9fa1cb39 | 586 | spin_lock(&aio_nr_lock); |
4cd81c3d | 587 | if (aio_nr + nr_events > (aio_max_nr * 2UL) || |
2dd542b7 | 588 | aio_nr + nr_events < aio_nr) { |
9fa1cb39 | 589 | spin_unlock(&aio_nr_lock); |
1da177e4 | 590 | goto out_cleanup; |
2dd542b7 AV |
591 | } |
592 | aio_nr += ctx->max_reqs; | |
9fa1cb39 | 593 | spin_unlock(&aio_nr_lock); |
1da177e4 | 594 | |
723be6e3 KO |
595 | percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ |
596 | ||
caf4167a | 597 | pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
58c85dc2 | 598 | ctx, ctx->user_id, mm, ctx->nr_events); |
1da177e4 LT |
599 | return ctx; |
600 | ||
601 | out_cleanup: | |
e23754f8 | 602 | err = -EAGAIN; |
db446a08 | 603 | out_cleanup_noerr: |
e23754f8 | 604 | aio_free_ring(ctx); |
e1bdd5f2 KO |
605 | out_freepcpu: |
606 | free_percpu(ctx->cpu); | |
723be6e3 KO |
607 | out_freeref: |
608 | free_percpu(ctx->users.pcpu_count); | |
1da177e4 | 609 | out_freectx: |
36bc08cc GZ |
610 | if (ctx->aio_ring_file) |
611 | fput(ctx->aio_ring_file); | |
1da177e4 | 612 | kmem_cache_free(kioctx_cachep, ctx); |
caf4167a | 613 | pr_debug("error allocating ioctx %d\n", err); |
e23754f8 | 614 | return ERR_PTR(err); |
1da177e4 LT |
615 | } |
616 | ||
36f55889 KO |
617 | /* kill_ioctx |
618 | * Cancels all outstanding aio requests on an aio context. Used | |
619 | * when the processes owning a context have all exited to encourage | |
620 | * the rapid destruction of the kioctx. | |
621 | */ | |
db446a08 | 622 | static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx) |
36f55889 KO |
623 | { |
624 | if (!atomic_xchg(&ctx->dead, 1)) { | |
db446a08 BL |
625 | struct kioctx_table *table; |
626 | ||
627 | spin_lock(&mm->ioctx_lock); | |
628 | table = rcu_dereference(mm->ioctx_table); | |
629 | ||
630 | WARN_ON(ctx != table->table[ctx->id]); | |
631 | table->table[ctx->id] = NULL; | |
632 | spin_unlock(&mm->ioctx_lock); | |
633 | ||
723be6e3 KO |
634 | /* percpu_ref_kill() will do the necessary call_rcu() */ |
635 | wake_up_all(&ctx->wait); | |
dee11c23 | 636 | |
36f55889 | 637 | /* |
4fcc712f KO |
638 | * It'd be more correct to do this in free_ioctx(), after all |
639 | * the outstanding kiocbs have finished - but by then io_destroy | |
640 | * has already returned, so io_setup() could potentially return | |
641 | * -EAGAIN with no ioctxs actually in use (as far as userspace | |
642 | * could tell). | |
36f55889 | 643 | */ |
4fcc712f KO |
644 | spin_lock(&aio_nr_lock); |
645 | BUG_ON(aio_nr - ctx->max_reqs > aio_nr); | |
646 | aio_nr -= ctx->max_reqs; | |
647 | spin_unlock(&aio_nr_lock); | |
648 | ||
649 | if (ctx->mmap_size) | |
650 | vm_munmap(ctx->mmap_base, ctx->mmap_size); | |
651 | ||
723be6e3 | 652 | percpu_ref_kill(&ctx->users); |
36f55889 | 653 | } |
1da177e4 LT |
654 | } |
655 | ||
656 | /* wait_on_sync_kiocb: | |
657 | * Waits on the given sync kiocb to complete. | |
658 | */ | |
57282d8f | 659 | ssize_t wait_on_sync_kiocb(struct kiocb *req) |
1da177e4 | 660 | { |
57282d8f | 661 | while (!req->ki_ctx) { |
1da177e4 | 662 | set_current_state(TASK_UNINTERRUPTIBLE); |
57282d8f | 663 | if (req->ki_ctx) |
1da177e4 | 664 | break; |
41d10da3 | 665 | io_schedule(); |
1da177e4 LT |
666 | } |
667 | __set_current_state(TASK_RUNNING); | |
57282d8f | 668 | return req->ki_user_data; |
1da177e4 | 669 | } |
385773e0 | 670 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
1da177e4 | 671 | |
36f55889 KO |
672 | /* |
673 | * exit_aio: called when the last user of mm goes away. At this point, there is | |
674 | * no way for any new requests to be submited or any of the io_* syscalls to be | |
675 | * called on the context. | |
676 | * | |
677 | * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on | |
678 | * them. | |
1da177e4 | 679 | */ |
fc9b52cd | 680 | void exit_aio(struct mm_struct *mm) |
1da177e4 | 681 | { |
db446a08 | 682 | struct kioctx_table *table; |
abf137dd | 683 | struct kioctx *ctx; |
db446a08 BL |
684 | unsigned i = 0; |
685 | ||
686 | while (1) { | |
687 | rcu_read_lock(); | |
688 | table = rcu_dereference(mm->ioctx_table); | |
689 | ||
690 | do { | |
691 | if (!table || i >= table->nr) { | |
692 | rcu_read_unlock(); | |
693 | rcu_assign_pointer(mm->ioctx_table, NULL); | |
694 | if (table) | |
695 | kfree(table); | |
696 | return; | |
697 | } | |
698 | ||
699 | ctx = table->table[i++]; | |
700 | } while (!ctx); | |
701 | ||
702 | rcu_read_unlock(); | |
abf137dd | 703 | |
936af157 AV |
704 | /* |
705 | * We don't need to bother with munmap() here - | |
706 | * exit_mmap(mm) is coming and it'll unmap everything. | |
707 | * Since aio_free_ring() uses non-zero ->mmap_size | |
708 | * as indicator that it needs to unmap the area, | |
709 | * just set it to 0; aio_free_ring() is the only | |
710 | * place that uses ->mmap_size, so it's safe. | |
936af157 | 711 | */ |
58c85dc2 | 712 | ctx->mmap_size = 0; |
36f55889 | 713 | |
db446a08 | 714 | kill_ioctx(mm, ctx); |
1da177e4 LT |
715 | } |
716 | } | |
717 | ||
e1bdd5f2 KO |
718 | static void put_reqs_available(struct kioctx *ctx, unsigned nr) |
719 | { | |
720 | struct kioctx_cpu *kcpu; | |
721 | ||
722 | preempt_disable(); | |
723 | kcpu = this_cpu_ptr(ctx->cpu); | |
724 | ||
725 | kcpu->reqs_available += nr; | |
726 | while (kcpu->reqs_available >= ctx->req_batch * 2) { | |
727 | kcpu->reqs_available -= ctx->req_batch; | |
728 | atomic_add(ctx->req_batch, &ctx->reqs_available); | |
729 | } | |
730 | ||
731 | preempt_enable(); | |
732 | } | |
733 | ||
734 | static bool get_reqs_available(struct kioctx *ctx) | |
735 | { | |
736 | struct kioctx_cpu *kcpu; | |
737 | bool ret = false; | |
738 | ||
739 | preempt_disable(); | |
740 | kcpu = this_cpu_ptr(ctx->cpu); | |
741 | ||
742 | if (!kcpu->reqs_available) { | |
743 | int old, avail = atomic_read(&ctx->reqs_available); | |
744 | ||
745 | do { | |
746 | if (avail < ctx->req_batch) | |
747 | goto out; | |
748 | ||
749 | old = avail; | |
750 | avail = atomic_cmpxchg(&ctx->reqs_available, | |
751 | avail, avail - ctx->req_batch); | |
752 | } while (avail != old); | |
753 | ||
754 | kcpu->reqs_available += ctx->req_batch; | |
755 | } | |
756 | ||
757 | ret = true; | |
758 | kcpu->reqs_available--; | |
759 | out: | |
760 | preempt_enable(); | |
761 | return ret; | |
762 | } | |
763 | ||
1da177e4 | 764 | /* aio_get_req |
57282d8f KO |
765 | * Allocate a slot for an aio request. |
766 | * Returns NULL if no requests are free. | |
1da177e4 | 767 | */ |
a1c8eae7 | 768 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
1da177e4 | 769 | { |
a1c8eae7 KO |
770 | struct kiocb *req; |
771 | ||
e1bdd5f2 | 772 | if (!get_reqs_available(ctx)) |
a1c8eae7 KO |
773 | return NULL; |
774 | ||
0460fef2 | 775 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); |
1da177e4 | 776 | if (unlikely(!req)) |
a1c8eae7 | 777 | goto out_put; |
1da177e4 | 778 | |
1da177e4 | 779 | req->ki_ctx = ctx; |
080d676d | 780 | return req; |
a1c8eae7 | 781 | out_put: |
e1bdd5f2 | 782 | put_reqs_available(ctx, 1); |
a1c8eae7 | 783 | return NULL; |
1da177e4 LT |
784 | } |
785 | ||
11599eba | 786 | static void kiocb_free(struct kiocb *req) |
1da177e4 | 787 | { |
1d98ebfc KO |
788 | if (req->ki_filp) |
789 | fput(req->ki_filp); | |
13389010 DL |
790 | if (req->ki_eventfd != NULL) |
791 | eventfd_ctx_put(req->ki_eventfd); | |
1da177e4 | 792 | kmem_cache_free(kiocb_cachep, req); |
1da177e4 LT |
793 | } |
794 | ||
d5470b59 | 795 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
1da177e4 | 796 | { |
db446a08 | 797 | struct aio_ring __user *ring = (void __user *)ctx_id; |
abf137dd | 798 | struct mm_struct *mm = current->mm; |
65c24491 | 799 | struct kioctx *ctx, *ret = NULL; |
db446a08 BL |
800 | struct kioctx_table *table; |
801 | unsigned id; | |
802 | ||
803 | if (get_user(id, &ring->id)) | |
804 | return NULL; | |
1da177e4 | 805 | |
abf137dd | 806 | rcu_read_lock(); |
db446a08 | 807 | table = rcu_dereference(mm->ioctx_table); |
abf137dd | 808 | |
db446a08 BL |
809 | if (!table || id >= table->nr) |
810 | goto out; | |
1da177e4 | 811 | |
db446a08 BL |
812 | ctx = table->table[id]; |
813 | if (ctx->user_id == ctx_id) { | |
814 | percpu_ref_get(&ctx->users); | |
815 | ret = ctx; | |
816 | } | |
817 | out: | |
abf137dd | 818 | rcu_read_unlock(); |
65c24491 | 819 | return ret; |
1da177e4 LT |
820 | } |
821 | ||
1da177e4 LT |
822 | /* aio_complete |
823 | * Called when the io request on the given iocb is complete. | |
1da177e4 | 824 | */ |
2d68449e | 825 | void aio_complete(struct kiocb *iocb, long res, long res2) |
1da177e4 LT |
826 | { |
827 | struct kioctx *ctx = iocb->ki_ctx; | |
1da177e4 | 828 | struct aio_ring *ring; |
21b40200 | 829 | struct io_event *ev_page, *event; |
1da177e4 | 830 | unsigned long flags; |
21b40200 | 831 | unsigned tail, pos; |
1da177e4 | 832 | |
20dcae32 ZB |
833 | /* |
834 | * Special case handling for sync iocbs: | |
835 | * - events go directly into the iocb for fast handling | |
836 | * - the sync task with the iocb in its stack holds the single iocb | |
837 | * ref, no other paths have a way to get another ref | |
838 | * - the sync task helpfully left a reference to itself in the iocb | |
1da177e4 LT |
839 | */ |
840 | if (is_sync_kiocb(iocb)) { | |
1da177e4 | 841 | iocb->ki_user_data = res; |
57282d8f KO |
842 | smp_wmb(); |
843 | iocb->ki_ctx = ERR_PTR(-EXDEV); | |
1da177e4 | 844 | wake_up_process(iocb->ki_obj.tsk); |
2d68449e | 845 | return; |
1da177e4 LT |
846 | } |
847 | ||
36f55889 | 848 | /* |
36f55889 | 849 | * Take rcu_read_lock() in case the kioctx is being destroyed, as we |
34e83fc6 | 850 | * need to issue a wakeup after incrementing reqs_available. |
1da177e4 | 851 | */ |
36f55889 | 852 | rcu_read_lock(); |
1da177e4 | 853 | |
0460fef2 KO |
854 | if (iocb->ki_list.next) { |
855 | unsigned long flags; | |
856 | ||
857 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
858 | list_del(&iocb->ki_list); | |
859 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
860 | } | |
11599eba | 861 | |
0460fef2 KO |
862 | /* |
863 | * Add a completion event to the ring buffer. Must be done holding | |
4b30f07e | 864 | * ctx->completion_lock to prevent other code from messing with the tail |
0460fef2 KO |
865 | * pointer since we might be called from irq context. |
866 | */ | |
867 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
868 | ||
58c85dc2 | 869 | tail = ctx->tail; |
21b40200 KO |
870 | pos = tail + AIO_EVENTS_OFFSET; |
871 | ||
58c85dc2 | 872 | if (++tail >= ctx->nr_events) |
4bf69b2a | 873 | tail = 0; |
1da177e4 | 874 | |
58c85dc2 | 875 | ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
876 | event = ev_page + pos % AIO_EVENTS_PER_PAGE; |
877 | ||
1da177e4 LT |
878 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
879 | event->data = iocb->ki_user_data; | |
880 | event->res = res; | |
881 | event->res2 = res2; | |
882 | ||
21b40200 | 883 | kunmap_atomic(ev_page); |
58c85dc2 | 884 | flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
885 | |
886 | pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n", | |
caf4167a KO |
887 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
888 | res, res2); | |
1da177e4 LT |
889 | |
890 | /* after flagging the request as done, we | |
891 | * must never even look at it again | |
892 | */ | |
893 | smp_wmb(); /* make event visible before updating tail */ | |
894 | ||
58c85dc2 | 895 | ctx->tail = tail; |
1da177e4 | 896 | |
58c85dc2 | 897 | ring = kmap_atomic(ctx->ring_pages[0]); |
21b40200 | 898 | ring->tail = tail; |
e8e3c3d6 | 899 | kunmap_atomic(ring); |
58c85dc2 | 900 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 | 901 | |
0460fef2 KO |
902 | spin_unlock_irqrestore(&ctx->completion_lock, flags); |
903 | ||
21b40200 | 904 | pr_debug("added to ring %p at [%u]\n", iocb, tail); |
8d1c98b0 DL |
905 | |
906 | /* | |
907 | * Check if the user asked us to deliver the result through an | |
908 | * eventfd. The eventfd_signal() function is safe to be called | |
909 | * from IRQ context. | |
910 | */ | |
87c3a86e | 911 | if (iocb->ki_eventfd != NULL) |
8d1c98b0 DL |
912 | eventfd_signal(iocb->ki_eventfd, 1); |
913 | ||
1da177e4 | 914 | /* everything turned out well, dispose of the aiocb. */ |
57282d8f | 915 | kiocb_free(iocb); |
1da177e4 | 916 | |
6cb2a210 QB |
917 | /* |
918 | * We have to order our ring_info tail store above and test | |
919 | * of the wait list below outside the wait lock. This is | |
920 | * like in wake_up_bit() where clearing a bit has to be | |
921 | * ordered with the unlocked test. | |
922 | */ | |
923 | smp_mb(); | |
924 | ||
1da177e4 LT |
925 | if (waitqueue_active(&ctx->wait)) |
926 | wake_up(&ctx->wait); | |
927 | ||
36f55889 | 928 | rcu_read_unlock(); |
1da177e4 | 929 | } |
385773e0 | 930 | EXPORT_SYMBOL(aio_complete); |
1da177e4 | 931 | |
a31ad380 KO |
932 | /* aio_read_events |
933 | * Pull an event off of the ioctx's event ring. Returns the number of | |
934 | * events fetched | |
1da177e4 | 935 | */ |
a31ad380 KO |
936 | static long aio_read_events_ring(struct kioctx *ctx, |
937 | struct io_event __user *event, long nr) | |
1da177e4 | 938 | { |
1da177e4 | 939 | struct aio_ring *ring; |
5ffac122 | 940 | unsigned head, tail, pos; |
a31ad380 KO |
941 | long ret = 0; |
942 | int copy_ret; | |
943 | ||
58c85dc2 | 944 | mutex_lock(&ctx->ring_lock); |
1da177e4 | 945 | |
58c85dc2 | 946 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 947 | head = ring->head; |
5ffac122 | 948 | tail = ring->tail; |
a31ad380 KO |
949 | kunmap_atomic(ring); |
950 | ||
5ffac122 | 951 | pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); |
1da177e4 | 952 | |
5ffac122 | 953 | if (head == tail) |
1da177e4 LT |
954 | goto out; |
955 | ||
a31ad380 KO |
956 | while (ret < nr) { |
957 | long avail; | |
958 | struct io_event *ev; | |
959 | struct page *page; | |
960 | ||
5ffac122 KO |
961 | avail = (head <= tail ? tail : ctx->nr_events) - head; |
962 | if (head == tail) | |
a31ad380 KO |
963 | break; |
964 | ||
965 | avail = min(avail, nr - ret); | |
966 | avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - | |
967 | ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE)); | |
968 | ||
969 | pos = head + AIO_EVENTS_OFFSET; | |
58c85dc2 | 970 | page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; |
a31ad380 KO |
971 | pos %= AIO_EVENTS_PER_PAGE; |
972 | ||
973 | ev = kmap(page); | |
974 | copy_ret = copy_to_user(event + ret, ev + pos, | |
975 | sizeof(*ev) * avail); | |
976 | kunmap(page); | |
977 | ||
978 | if (unlikely(copy_ret)) { | |
979 | ret = -EFAULT; | |
980 | goto out; | |
981 | } | |
982 | ||
983 | ret += avail; | |
984 | head += avail; | |
58c85dc2 | 985 | head %= ctx->nr_events; |
1da177e4 | 986 | } |
1da177e4 | 987 | |
58c85dc2 | 988 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 989 | ring->head = head; |
91d80a84 | 990 | kunmap_atomic(ring); |
58c85dc2 | 991 | flush_dcache_page(ctx->ring_pages[0]); |
a31ad380 | 992 | |
5ffac122 | 993 | pr_debug("%li h%u t%u\n", ret, head, tail); |
3e845ce0 | 994 | |
e1bdd5f2 | 995 | put_reqs_available(ctx, ret); |
a31ad380 | 996 | out: |
58c85dc2 | 997 | mutex_unlock(&ctx->ring_lock); |
a31ad380 | 998 | |
1da177e4 LT |
999 | return ret; |
1000 | } | |
1001 | ||
a31ad380 KO |
1002 | static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, |
1003 | struct io_event __user *event, long *i) | |
1da177e4 | 1004 | { |
a31ad380 | 1005 | long ret = aio_read_events_ring(ctx, event + *i, nr - *i); |
1da177e4 | 1006 | |
a31ad380 KO |
1007 | if (ret > 0) |
1008 | *i += ret; | |
1da177e4 | 1009 | |
a31ad380 KO |
1010 | if (unlikely(atomic_read(&ctx->dead))) |
1011 | ret = -EINVAL; | |
1da177e4 | 1012 | |
a31ad380 KO |
1013 | if (!*i) |
1014 | *i = ret; | |
1da177e4 | 1015 | |
a31ad380 | 1016 | return ret < 0 || *i >= min_nr; |
1da177e4 LT |
1017 | } |
1018 | ||
a31ad380 | 1019 | static long read_events(struct kioctx *ctx, long min_nr, long nr, |
1da177e4 LT |
1020 | struct io_event __user *event, |
1021 | struct timespec __user *timeout) | |
1022 | { | |
a31ad380 KO |
1023 | ktime_t until = { .tv64 = KTIME_MAX }; |
1024 | long ret = 0; | |
1da177e4 | 1025 | |
1da177e4 LT |
1026 | if (timeout) { |
1027 | struct timespec ts; | |
a31ad380 | 1028 | |
1da177e4 | 1029 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
a31ad380 | 1030 | return -EFAULT; |
1da177e4 | 1031 | |
a31ad380 | 1032 | until = timespec_to_ktime(ts); |
1da177e4 LT |
1033 | } |
1034 | ||
a31ad380 KO |
1035 | /* |
1036 | * Note that aio_read_events() is being called as the conditional - i.e. | |
1037 | * we're calling it after prepare_to_wait() has set task state to | |
1038 | * TASK_INTERRUPTIBLE. | |
1039 | * | |
1040 | * But aio_read_events() can block, and if it blocks it's going to flip | |
1041 | * the task state back to TASK_RUNNING. | |
1042 | * | |
1043 | * This should be ok, provided it doesn't flip the state back to | |
1044 | * TASK_RUNNING and return 0 too much - that causes us to spin. That | |
1045 | * will only happen if the mutex_lock() call blocks, and we then find | |
1046 | * the ringbuffer empty. So in practice we should be ok, but it's | |
1047 | * something to be aware of when touching this code. | |
1048 | */ | |
1049 | wait_event_interruptible_hrtimeout(ctx->wait, | |
1050 | aio_read_events(ctx, min_nr, nr, event, &ret), until); | |
1da177e4 | 1051 | |
a31ad380 KO |
1052 | if (!ret && signal_pending(current)) |
1053 | ret = -EINTR; | |
1da177e4 | 1054 | |
a31ad380 | 1055 | return ret; |
1da177e4 LT |
1056 | } |
1057 | ||
1da177e4 LT |
1058 | /* sys_io_setup: |
1059 | * Create an aio_context capable of receiving at least nr_events. | |
1060 | * ctxp must not point to an aio_context that already exists, and | |
1061 | * must be initialized to 0 prior to the call. On successful | |
1062 | * creation of the aio_context, *ctxp is filled in with the resulting | |
1063 | * handle. May fail with -EINVAL if *ctxp is not initialized, | |
1064 | * if the specified nr_events exceeds internal limits. May fail | |
1065 | * with -EAGAIN if the specified nr_events exceeds the user's limit | |
1066 | * of available events. May fail with -ENOMEM if insufficient kernel | |
1067 | * resources are available. May fail with -EFAULT if an invalid | |
1068 | * pointer is passed for ctxp. Will fail with -ENOSYS if not | |
1069 | * implemented. | |
1070 | */ | |
002c8976 | 1071 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1da177e4 LT |
1072 | { |
1073 | struct kioctx *ioctx = NULL; | |
1074 | unsigned long ctx; | |
1075 | long ret; | |
1076 | ||
1077 | ret = get_user(ctx, ctxp); | |
1078 | if (unlikely(ret)) | |
1079 | goto out; | |
1080 | ||
1081 | ret = -EINVAL; | |
d55b5fda ZB |
1082 | if (unlikely(ctx || nr_events == 0)) { |
1083 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", | |
1084 | ctx, nr_events); | |
1da177e4 LT |
1085 | goto out; |
1086 | } | |
1087 | ||
1088 | ioctx = ioctx_alloc(nr_events); | |
1089 | ret = PTR_ERR(ioctx); | |
1090 | if (!IS_ERR(ioctx)) { | |
1091 | ret = put_user(ioctx->user_id, ctxp); | |
a2e1859a | 1092 | if (ret) |
db446a08 | 1093 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1094 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1095 | } |
1096 | ||
1097 | out: | |
1098 | return ret; | |
1099 | } | |
1100 | ||
1101 | /* sys_io_destroy: | |
1102 | * Destroy the aio_context specified. May cancel any outstanding | |
1103 | * AIOs and block on completion. Will fail with -ENOSYS if not | |
642b5123 | 1104 | * implemented. May fail with -EINVAL if the context pointed to |
1da177e4 LT |
1105 | * is invalid. |
1106 | */ | |
002c8976 | 1107 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1da177e4 LT |
1108 | { |
1109 | struct kioctx *ioctx = lookup_ioctx(ctx); | |
1110 | if (likely(NULL != ioctx)) { | |
db446a08 | 1111 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1112 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1113 | return 0; |
1114 | } | |
1115 | pr_debug("EINVAL: io_destroy: invalid context id\n"); | |
1116 | return -EINVAL; | |
1117 | } | |
1118 | ||
41ef4eb8 KO |
1119 | typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *, |
1120 | unsigned long, loff_t); | |
1121 | ||
8bc92afc KO |
1122 | static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb, |
1123 | int rw, char __user *buf, | |
1124 | unsigned long *nr_segs, | |
1125 | struct iovec **iovec, | |
1126 | bool compat) | |
eed4e51f BP |
1127 | { |
1128 | ssize_t ret; | |
1129 | ||
8bc92afc | 1130 | *nr_segs = kiocb->ki_nbytes; |
41ef4eb8 | 1131 | |
9d85cba7 JM |
1132 | #ifdef CONFIG_COMPAT |
1133 | if (compat) | |
41ef4eb8 | 1134 | ret = compat_rw_copy_check_uvector(rw, |
8bc92afc KO |
1135 | (struct compat_iovec __user *)buf, |
1136 | *nr_segs, 1, *iovec, iovec); | |
9d85cba7 JM |
1137 | else |
1138 | #endif | |
41ef4eb8 | 1139 | ret = rw_copy_check_uvector(rw, |
8bc92afc KO |
1140 | (struct iovec __user *)buf, |
1141 | *nr_segs, 1, *iovec, iovec); | |
eed4e51f | 1142 | if (ret < 0) |
41ef4eb8 | 1143 | return ret; |
a70b52ec | 1144 | |
41ef4eb8 | 1145 | /* ki_nbytes now reflect bytes instead of segs */ |
eed4e51f | 1146 | kiocb->ki_nbytes = ret; |
41ef4eb8 | 1147 | return 0; |
eed4e51f BP |
1148 | } |
1149 | ||
8bc92afc KO |
1150 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb, |
1151 | int rw, char __user *buf, | |
1152 | unsigned long *nr_segs, | |
1153 | struct iovec *iovec) | |
eed4e51f | 1154 | { |
8bc92afc | 1155 | if (unlikely(!access_ok(!rw, buf, kiocb->ki_nbytes))) |
41ef4eb8 | 1156 | return -EFAULT; |
a70b52ec | 1157 | |
8bc92afc KO |
1158 | iovec->iov_base = buf; |
1159 | iovec->iov_len = kiocb->ki_nbytes; | |
1160 | *nr_segs = 1; | |
eed4e51f BP |
1161 | return 0; |
1162 | } | |
1163 | ||
1da177e4 LT |
1164 | /* |
1165 | * aio_setup_iocb: | |
1166 | * Performs the initial checks and aio retry method | |
1167 | * setup for the kiocb at the time of io submission. | |
1168 | */ | |
8bc92afc KO |
1169 | static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode, |
1170 | char __user *buf, bool compat) | |
1da177e4 | 1171 | { |
41ef4eb8 KO |
1172 | struct file *file = req->ki_filp; |
1173 | ssize_t ret; | |
8bc92afc | 1174 | unsigned long nr_segs; |
41ef4eb8 KO |
1175 | int rw; |
1176 | fmode_t mode; | |
1177 | aio_rw_op *rw_op; | |
8bc92afc | 1178 | struct iovec inline_vec, *iovec = &inline_vec; |
1da177e4 | 1179 | |
8bc92afc | 1180 | switch (opcode) { |
1da177e4 | 1181 | case IOCB_CMD_PREAD: |
eed4e51f | 1182 | case IOCB_CMD_PREADV: |
41ef4eb8 KO |
1183 | mode = FMODE_READ; |
1184 | rw = READ; | |
1185 | rw_op = file->f_op->aio_read; | |
1186 | goto rw_common; | |
1187 | ||
1188 | case IOCB_CMD_PWRITE: | |
eed4e51f | 1189 | case IOCB_CMD_PWRITEV: |
41ef4eb8 KO |
1190 | mode = FMODE_WRITE; |
1191 | rw = WRITE; | |
1192 | rw_op = file->f_op->aio_write; | |
1193 | goto rw_common; | |
1194 | rw_common: | |
1195 | if (unlikely(!(file->f_mode & mode))) | |
1196 | return -EBADF; | |
1197 | ||
1198 | if (!rw_op) | |
1199 | return -EINVAL; | |
1200 | ||
8bc92afc KO |
1201 | ret = (opcode == IOCB_CMD_PREADV || |
1202 | opcode == IOCB_CMD_PWRITEV) | |
1203 | ? aio_setup_vectored_rw(req, rw, buf, &nr_segs, | |
1204 | &iovec, compat) | |
1205 | : aio_setup_single_vector(req, rw, buf, &nr_segs, | |
1206 | iovec); | |
eed4e51f | 1207 | if (ret) |
41ef4eb8 KO |
1208 | return ret; |
1209 | ||
1210 | ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes); | |
8bc92afc KO |
1211 | if (ret < 0) { |
1212 | if (iovec != &inline_vec) | |
1213 | kfree(iovec); | |
41ef4eb8 | 1214 | return ret; |
8bc92afc | 1215 | } |
41ef4eb8 KO |
1216 | |
1217 | req->ki_nbytes = ret; | |
41ef4eb8 | 1218 | |
73a7075e KO |
1219 | /* XXX: move/kill - rw_verify_area()? */ |
1220 | /* This matches the pread()/pwrite() logic */ | |
1221 | if (req->ki_pos < 0) { | |
1222 | ret = -EINVAL; | |
1223 | break; | |
1224 | } | |
1225 | ||
1226 | if (rw == WRITE) | |
1227 | file_start_write(file); | |
1228 | ||
8bc92afc | 1229 | ret = rw_op(req, iovec, nr_segs, req->ki_pos); |
73a7075e KO |
1230 | |
1231 | if (rw == WRITE) | |
1232 | file_end_write(file); | |
1da177e4 | 1233 | break; |
41ef4eb8 | 1234 | |
1da177e4 | 1235 | case IOCB_CMD_FDSYNC: |
41ef4eb8 KO |
1236 | if (!file->f_op->aio_fsync) |
1237 | return -EINVAL; | |
1238 | ||
1239 | ret = file->f_op->aio_fsync(req, 1); | |
1da177e4 | 1240 | break; |
41ef4eb8 | 1241 | |
1da177e4 | 1242 | case IOCB_CMD_FSYNC: |
41ef4eb8 KO |
1243 | if (!file->f_op->aio_fsync) |
1244 | return -EINVAL; | |
1245 | ||
1246 | ret = file->f_op->aio_fsync(req, 0); | |
1da177e4 | 1247 | break; |
41ef4eb8 | 1248 | |
1da177e4 | 1249 | default: |
caf4167a | 1250 | pr_debug("EINVAL: no operation provided\n"); |
41ef4eb8 | 1251 | return -EINVAL; |
1da177e4 LT |
1252 | } |
1253 | ||
8bc92afc KO |
1254 | if (iovec != &inline_vec) |
1255 | kfree(iovec); | |
1256 | ||
41ef4eb8 KO |
1257 | if (ret != -EIOCBQUEUED) { |
1258 | /* | |
1259 | * There's no easy way to restart the syscall since other AIO's | |
1260 | * may be already running. Just fail this IO with EINTR. | |
1261 | */ | |
1262 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || | |
1263 | ret == -ERESTARTNOHAND || | |
1264 | ret == -ERESTART_RESTARTBLOCK)) | |
1265 | ret = -EINTR; | |
1266 | aio_complete(req, ret, 0); | |
1267 | } | |
1da177e4 LT |
1268 | |
1269 | return 0; | |
1270 | } | |
1271 | ||
d5470b59 | 1272 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
a1c8eae7 | 1273 | struct iocb *iocb, bool compat) |
1da177e4 LT |
1274 | { |
1275 | struct kiocb *req; | |
1da177e4 LT |
1276 | ssize_t ret; |
1277 | ||
1278 | /* enforce forwards compatibility on users */ | |
9c3060be | 1279 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
caf4167a | 1280 | pr_debug("EINVAL: reserve field set\n"); |
1da177e4 LT |
1281 | return -EINVAL; |
1282 | } | |
1283 | ||
1284 | /* prevent overflows */ | |
1285 | if (unlikely( | |
1286 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || | |
1287 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || | |
1288 | ((ssize_t)iocb->aio_nbytes < 0) | |
1289 | )) { | |
1290 | pr_debug("EINVAL: io_submit: overflow check\n"); | |
1291 | return -EINVAL; | |
1292 | } | |
1293 | ||
41ef4eb8 | 1294 | req = aio_get_req(ctx); |
1d98ebfc | 1295 | if (unlikely(!req)) |
1da177e4 | 1296 | return -EAGAIN; |
1d98ebfc KO |
1297 | |
1298 | req->ki_filp = fget(iocb->aio_fildes); | |
1299 | if (unlikely(!req->ki_filp)) { | |
1300 | ret = -EBADF; | |
1301 | goto out_put_req; | |
1da177e4 | 1302 | } |
1d98ebfc | 1303 | |
9c3060be DL |
1304 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1305 | /* | |
1306 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an | |
1307 | * instance of the file* now. The file descriptor must be | |
1308 | * an eventfd() fd, and will be signaled for each completed | |
1309 | * event using the eventfd_signal() function. | |
1310 | */ | |
13389010 | 1311 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
801678c5 | 1312 | if (IS_ERR(req->ki_eventfd)) { |
9c3060be | 1313 | ret = PTR_ERR(req->ki_eventfd); |
87c3a86e | 1314 | req->ki_eventfd = NULL; |
9c3060be DL |
1315 | goto out_put_req; |
1316 | } | |
1317 | } | |
1da177e4 | 1318 | |
8a660890 | 1319 | ret = put_user(KIOCB_KEY, &user_iocb->aio_key); |
1da177e4 | 1320 | if (unlikely(ret)) { |
caf4167a | 1321 | pr_debug("EFAULT: aio_key\n"); |
1da177e4 LT |
1322 | goto out_put_req; |
1323 | } | |
1324 | ||
1325 | req->ki_obj.user = user_iocb; | |
1326 | req->ki_user_data = iocb->aio_data; | |
1327 | req->ki_pos = iocb->aio_offset; | |
73a7075e | 1328 | req->ki_nbytes = iocb->aio_nbytes; |
1da177e4 | 1329 | |
8bc92afc KO |
1330 | ret = aio_run_iocb(req, iocb->aio_lio_opcode, |
1331 | (char __user *)(unsigned long)iocb->aio_buf, | |
1332 | compat); | |
41003a7b | 1333 | if (ret) |
7137c6bd | 1334 | goto out_put_req; |
41003a7b | 1335 | |
1da177e4 | 1336 | return 0; |
1da177e4 | 1337 | out_put_req: |
e1bdd5f2 | 1338 | put_reqs_available(ctx, 1); |
57282d8f | 1339 | kiocb_free(req); |
1da177e4 LT |
1340 | return ret; |
1341 | } | |
1342 | ||
9d85cba7 JM |
1343 | long do_io_submit(aio_context_t ctx_id, long nr, |
1344 | struct iocb __user *__user *iocbpp, bool compat) | |
1da177e4 LT |
1345 | { |
1346 | struct kioctx *ctx; | |
1347 | long ret = 0; | |
080d676d | 1348 | int i = 0; |
9f5b9425 | 1349 | struct blk_plug plug; |
1da177e4 LT |
1350 | |
1351 | if (unlikely(nr < 0)) | |
1352 | return -EINVAL; | |
1353 | ||
75e1c70f JM |
1354 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1355 | nr = LONG_MAX/sizeof(*iocbpp); | |
1356 | ||
1da177e4 LT |
1357 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1358 | return -EFAULT; | |
1359 | ||
1360 | ctx = lookup_ioctx(ctx_id); | |
1361 | if (unlikely(!ctx)) { | |
caf4167a | 1362 | pr_debug("EINVAL: invalid context id\n"); |
1da177e4 LT |
1363 | return -EINVAL; |
1364 | } | |
1365 | ||
9f5b9425 SL |
1366 | blk_start_plug(&plug); |
1367 | ||
1da177e4 LT |
1368 | /* |
1369 | * AKPM: should this return a partial result if some of the IOs were | |
1370 | * successfully submitted? | |
1371 | */ | |
1372 | for (i=0; i<nr; i++) { | |
1373 | struct iocb __user *user_iocb; | |
1374 | struct iocb tmp; | |
1375 | ||
1376 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { | |
1377 | ret = -EFAULT; | |
1378 | break; | |
1379 | } | |
1380 | ||
1381 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { | |
1382 | ret = -EFAULT; | |
1383 | break; | |
1384 | } | |
1385 | ||
a1c8eae7 | 1386 | ret = io_submit_one(ctx, user_iocb, &tmp, compat); |
1da177e4 LT |
1387 | if (ret) |
1388 | break; | |
1389 | } | |
9f5b9425 | 1390 | blk_finish_plug(&plug); |
1da177e4 | 1391 | |
723be6e3 | 1392 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1393 | return i ? i : ret; |
1394 | } | |
1395 | ||
9d85cba7 JM |
1396 | /* sys_io_submit: |
1397 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns | |
1398 | * the number of iocbs queued. May return -EINVAL if the aio_context | |
1399 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at | |
1400 | * *iocbpp[0] is not properly initialized, if the operation specified | |
1401 | * is invalid for the file descriptor in the iocb. May fail with | |
1402 | * -EFAULT if any of the data structures point to invalid data. May | |
1403 | * fail with -EBADF if the file descriptor specified in the first | |
1404 | * iocb is invalid. May fail with -EAGAIN if insufficient resources | |
1405 | * are available to queue any iocbs. Will return 0 if nr is 0. Will | |
1406 | * fail with -ENOSYS if not implemented. | |
1407 | */ | |
1408 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, | |
1409 | struct iocb __user * __user *, iocbpp) | |
1410 | { | |
1411 | return do_io_submit(ctx_id, nr, iocbpp, 0); | |
1412 | } | |
1413 | ||
1da177e4 LT |
1414 | /* lookup_kiocb |
1415 | * Finds a given iocb for cancellation. | |
1da177e4 | 1416 | */ |
25ee7e38 AB |
1417 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1418 | u32 key) | |
1da177e4 LT |
1419 | { |
1420 | struct list_head *pos; | |
d00689af ZB |
1421 | |
1422 | assert_spin_locked(&ctx->ctx_lock); | |
1423 | ||
8a660890 KO |
1424 | if (key != KIOCB_KEY) |
1425 | return NULL; | |
1426 | ||
1da177e4 LT |
1427 | /* TODO: use a hash or array, this sucks. */ |
1428 | list_for_each(pos, &ctx->active_reqs) { | |
1429 | struct kiocb *kiocb = list_kiocb(pos); | |
8a660890 | 1430 | if (kiocb->ki_obj.user == iocb) |
1da177e4 LT |
1431 | return kiocb; |
1432 | } | |
1433 | return NULL; | |
1434 | } | |
1435 | ||
1436 | /* sys_io_cancel: | |
1437 | * Attempts to cancel an iocb previously passed to io_submit. If | |
1438 | * the operation is successfully cancelled, the resulting event is | |
1439 | * copied into the memory pointed to by result without being placed | |
1440 | * into the completion queue and 0 is returned. May fail with | |
1441 | * -EFAULT if any of the data structures pointed to are invalid. | |
1442 | * May fail with -EINVAL if aio_context specified by ctx_id is | |
1443 | * invalid. May fail with -EAGAIN if the iocb specified was not | |
1444 | * cancelled. Will fail with -ENOSYS if not implemented. | |
1445 | */ | |
002c8976 HC |
1446 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1447 | struct io_event __user *, result) | |
1da177e4 | 1448 | { |
1da177e4 LT |
1449 | struct kioctx *ctx; |
1450 | struct kiocb *kiocb; | |
1451 | u32 key; | |
1452 | int ret; | |
1453 | ||
1454 | ret = get_user(key, &iocb->aio_key); | |
1455 | if (unlikely(ret)) | |
1456 | return -EFAULT; | |
1457 | ||
1458 | ctx = lookup_ioctx(ctx_id); | |
1459 | if (unlikely(!ctx)) | |
1460 | return -EINVAL; | |
1461 | ||
1462 | spin_lock_irq(&ctx->ctx_lock); | |
906b973c | 1463 | |
1da177e4 | 1464 | kiocb = lookup_kiocb(ctx, iocb, key); |
906b973c | 1465 | if (kiocb) |
bec68faa | 1466 | ret = kiocb_cancel(ctx, kiocb); |
906b973c KO |
1467 | else |
1468 | ret = -EINVAL; | |
1469 | ||
1da177e4 LT |
1470 | spin_unlock_irq(&ctx->ctx_lock); |
1471 | ||
906b973c | 1472 | if (!ret) { |
bec68faa KO |
1473 | /* |
1474 | * The result argument is no longer used - the io_event is | |
1475 | * always delivered via the ring buffer. -EINPROGRESS indicates | |
1476 | * cancellation is progress: | |
906b973c | 1477 | */ |
bec68faa | 1478 | ret = -EINPROGRESS; |
906b973c | 1479 | } |
1da177e4 | 1480 | |
723be6e3 | 1481 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1482 | |
1483 | return ret; | |
1484 | } | |
1485 | ||
1486 | /* io_getevents: | |
1487 | * Attempts to read at least min_nr events and up to nr events from | |
642b5123 ST |
1488 | * the completion queue for the aio_context specified by ctx_id. If |
1489 | * it succeeds, the number of read events is returned. May fail with | |
1490 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is | |
1491 | * out of range, if timeout is out of range. May fail with -EFAULT | |
1492 | * if any of the memory specified is invalid. May return 0 or | |
1493 | * < min_nr if the timeout specified by timeout has elapsed | |
1494 | * before sufficient events are available, where timeout == NULL | |
1495 | * specifies an infinite timeout. Note that the timeout pointed to by | |
6900807c | 1496 | * timeout is relative. Will fail with -ENOSYS if not implemented. |
1da177e4 | 1497 | */ |
002c8976 HC |
1498 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1499 | long, min_nr, | |
1500 | long, nr, | |
1501 | struct io_event __user *, events, | |
1502 | struct timespec __user *, timeout) | |
1da177e4 LT |
1503 | { |
1504 | struct kioctx *ioctx = lookup_ioctx(ctx_id); | |
1505 | long ret = -EINVAL; | |
1506 | ||
1507 | if (likely(ioctx)) { | |
2e410255 | 1508 | if (likely(min_nr <= nr && min_nr >= 0)) |
1da177e4 | 1509 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
723be6e3 | 1510 | percpu_ref_put(&ioctx->users); |
1da177e4 | 1511 | } |
1da177e4 LT |
1512 | return ret; |
1513 | } |