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Commit | Line | Data |
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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 | 169 | |
5e9ae2e5 BL |
170 | static void put_aio_ring_file(struct kioctx *ctx) |
171 | { | |
172 | struct file *aio_ring_file = ctx->aio_ring_file; | |
173 | if (aio_ring_file) { | |
174 | truncate_setsize(aio_ring_file->f_inode, 0); | |
175 | ||
176 | /* Prevent further access to the kioctx from migratepages */ | |
177 | spin_lock(&aio_ring_file->f_inode->i_mapping->private_lock); | |
178 | aio_ring_file->f_inode->i_mapping->private_data = NULL; | |
179 | ctx->aio_ring_file = NULL; | |
180 | spin_unlock(&aio_ring_file->f_inode->i_mapping->private_lock); | |
181 | ||
182 | fput(aio_ring_file); | |
183 | } | |
184 | } | |
185 | ||
1da177e4 LT |
186 | static void aio_free_ring(struct kioctx *ctx) |
187 | { | |
36bc08cc | 188 | int i; |
1da177e4 | 189 | |
36bc08cc GZ |
190 | for (i = 0; i < ctx->nr_pages; i++) { |
191 | pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, | |
192 | page_count(ctx->ring_pages[i])); | |
58c85dc2 | 193 | put_page(ctx->ring_pages[i]); |
36bc08cc | 194 | } |
1da177e4 | 195 | |
5e9ae2e5 BL |
196 | put_aio_ring_file(ctx); |
197 | ||
58c85dc2 KO |
198 | if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) |
199 | kfree(ctx->ring_pages); | |
36bc08cc GZ |
200 | } |
201 | ||
202 | static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) | |
203 | { | |
204 | vma->vm_ops = &generic_file_vm_ops; | |
205 | return 0; | |
206 | } | |
207 | ||
208 | static const struct file_operations aio_ring_fops = { | |
209 | .mmap = aio_ring_mmap, | |
210 | }; | |
211 | ||
212 | static int aio_set_page_dirty(struct page *page) | |
213 | { | |
214 | return 0; | |
215 | } | |
216 | ||
0c45355f | 217 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc GZ |
218 | static int aio_migratepage(struct address_space *mapping, struct page *new, |
219 | struct page *old, enum migrate_mode mode) | |
220 | { | |
5e9ae2e5 | 221 | struct kioctx *ctx; |
36bc08cc | 222 | unsigned long flags; |
36bc08cc GZ |
223 | int rc; |
224 | ||
225 | /* Writeback must be complete */ | |
226 | BUG_ON(PageWriteback(old)); | |
227 | put_page(old); | |
228 | ||
229 | rc = migrate_page_move_mapping(mapping, new, old, NULL, mode); | |
230 | if (rc != MIGRATEPAGE_SUCCESS) { | |
231 | get_page(old); | |
232 | return rc; | |
233 | } | |
234 | ||
235 | get_page(new); | |
236 | ||
5e9ae2e5 BL |
237 | /* We can potentially race against kioctx teardown here. Use the |
238 | * address_space's private data lock to protect the mapping's | |
239 | * private_data. | |
240 | */ | |
241 | spin_lock(&mapping->private_lock); | |
242 | ctx = mapping->private_data; | |
243 | if (ctx) { | |
244 | pgoff_t idx; | |
245 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
246 | migrate_page_copy(new, old); | |
247 | idx = old->index; | |
248 | if (idx < (pgoff_t)ctx->nr_pages) | |
249 | ctx->ring_pages[idx] = new; | |
250 | spin_unlock_irqrestore(&ctx->completion_lock, flags); | |
251 | } else | |
252 | rc = -EBUSY; | |
253 | spin_unlock(&mapping->private_lock); | |
36bc08cc GZ |
254 | |
255 | return rc; | |
1da177e4 | 256 | } |
0c45355f | 257 | #endif |
1da177e4 | 258 | |
36bc08cc GZ |
259 | static const struct address_space_operations aio_ctx_aops = { |
260 | .set_page_dirty = aio_set_page_dirty, | |
0c45355f | 261 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc | 262 | .migratepage = aio_migratepage, |
0c45355f | 263 | #endif |
36bc08cc GZ |
264 | }; |
265 | ||
1da177e4 LT |
266 | static int aio_setup_ring(struct kioctx *ctx) |
267 | { | |
268 | struct aio_ring *ring; | |
1da177e4 | 269 | unsigned nr_events = ctx->max_reqs; |
41003a7b | 270 | struct mm_struct *mm = current->mm; |
41badc15 | 271 | unsigned long size, populate; |
1da177e4 | 272 | int nr_pages; |
36bc08cc GZ |
273 | int i; |
274 | struct file *file; | |
1da177e4 LT |
275 | |
276 | /* Compensate for the ring buffer's head/tail overlap entry */ | |
277 | nr_events += 2; /* 1 is required, 2 for good luck */ | |
278 | ||
279 | size = sizeof(struct aio_ring); | |
280 | size += sizeof(struct io_event) * nr_events; | |
1da177e4 | 281 | |
36bc08cc | 282 | nr_pages = PFN_UP(size); |
1da177e4 LT |
283 | if (nr_pages < 0) |
284 | return -EINVAL; | |
285 | ||
36bc08cc GZ |
286 | file = anon_inode_getfile_private("[aio]", &aio_ring_fops, ctx, O_RDWR); |
287 | if (IS_ERR(file)) { | |
288 | ctx->aio_ring_file = NULL; | |
289 | return -EAGAIN; | |
290 | } | |
291 | ||
292 | file->f_inode->i_mapping->a_ops = &aio_ctx_aops; | |
293 | file->f_inode->i_mapping->private_data = ctx; | |
294 | file->f_inode->i_size = PAGE_SIZE * (loff_t)nr_pages; | |
295 | ||
296 | for (i = 0; i < nr_pages; i++) { | |
297 | struct page *page; | |
298 | page = find_or_create_page(file->f_inode->i_mapping, | |
299 | i, GFP_HIGHUSER | __GFP_ZERO); | |
300 | if (!page) | |
301 | break; | |
302 | pr_debug("pid(%d) page[%d]->count=%d\n", | |
303 | current->pid, i, page_count(page)); | |
304 | SetPageUptodate(page); | |
305 | SetPageDirty(page); | |
306 | unlock_page(page); | |
307 | } | |
308 | ctx->aio_ring_file = file; | |
309 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) | |
310 | / sizeof(struct io_event); | |
1da177e4 | 311 | |
58c85dc2 | 312 | ctx->ring_pages = ctx->internal_pages; |
1da177e4 | 313 | if (nr_pages > AIO_RING_PAGES) { |
58c85dc2 KO |
314 | ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), |
315 | GFP_KERNEL); | |
316 | if (!ctx->ring_pages) | |
1da177e4 | 317 | return -ENOMEM; |
1da177e4 LT |
318 | } |
319 | ||
58c85dc2 KO |
320 | ctx->mmap_size = nr_pages * PAGE_SIZE; |
321 | pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); | |
36bc08cc | 322 | |
41003a7b | 323 | down_write(&mm->mmap_sem); |
36bc08cc GZ |
324 | ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, |
325 | PROT_READ | PROT_WRITE, | |
326 | MAP_SHARED | MAP_POPULATE, 0, &populate); | |
58c85dc2 | 327 | if (IS_ERR((void *)ctx->mmap_base)) { |
41003a7b | 328 | up_write(&mm->mmap_sem); |
58c85dc2 | 329 | ctx->mmap_size = 0; |
1da177e4 LT |
330 | aio_free_ring(ctx); |
331 | return -EAGAIN; | |
332 | } | |
333 | ||
58c85dc2 | 334 | pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); |
d6c355c7 BL |
335 | |
336 | /* We must do this while still holding mmap_sem for write, as we | |
337 | * need to be protected against userspace attempting to mremap() | |
338 | * or munmap() the ring buffer. | |
339 | */ | |
58c85dc2 KO |
340 | ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages, |
341 | 1, 0, ctx->ring_pages, NULL); | |
d6c355c7 BL |
342 | |
343 | /* Dropping the reference here is safe as the page cache will hold | |
344 | * onto the pages for us. It is also required so that page migration | |
345 | * can unmap the pages and get the right reference count. | |
346 | */ | |
36bc08cc GZ |
347 | for (i = 0; i < ctx->nr_pages; i++) |
348 | put_page(ctx->ring_pages[i]); | |
1da177e4 | 349 | |
d6c355c7 BL |
350 | up_write(&mm->mmap_sem); |
351 | ||
58c85dc2 | 352 | if (unlikely(ctx->nr_pages != nr_pages)) { |
1da177e4 LT |
353 | aio_free_ring(ctx); |
354 | return -EAGAIN; | |
355 | } | |
356 | ||
58c85dc2 KO |
357 | ctx->user_id = ctx->mmap_base; |
358 | ctx->nr_events = nr_events; /* trusted copy */ | |
1da177e4 | 359 | |
58c85dc2 | 360 | ring = kmap_atomic(ctx->ring_pages[0]); |
1da177e4 | 361 | ring->nr = nr_events; /* user copy */ |
db446a08 | 362 | ring->id = ~0U; |
1da177e4 LT |
363 | ring->head = ring->tail = 0; |
364 | ring->magic = AIO_RING_MAGIC; | |
365 | ring->compat_features = AIO_RING_COMPAT_FEATURES; | |
366 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; | |
367 | ring->header_length = sizeof(struct aio_ring); | |
e8e3c3d6 | 368 | kunmap_atomic(ring); |
58c85dc2 | 369 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 LT |
370 | |
371 | return 0; | |
372 | } | |
373 | ||
1da177e4 LT |
374 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
375 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) | |
376 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) | |
377 | ||
0460fef2 KO |
378 | void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel) |
379 | { | |
380 | struct kioctx *ctx = req->ki_ctx; | |
381 | unsigned long flags; | |
382 | ||
383 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
384 | ||
385 | if (!req->ki_list.next) | |
386 | list_add(&req->ki_list, &ctx->active_reqs); | |
387 | ||
388 | req->ki_cancel = cancel; | |
389 | ||
390 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
391 | } | |
392 | EXPORT_SYMBOL(kiocb_set_cancel_fn); | |
393 | ||
bec68faa | 394 | static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb) |
906b973c | 395 | { |
0460fef2 | 396 | kiocb_cancel_fn *old, *cancel; |
906b973c | 397 | |
0460fef2 KO |
398 | /* |
399 | * Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it | |
400 | * actually has a cancel function, hence the cmpxchg() | |
401 | */ | |
402 | ||
403 | cancel = ACCESS_ONCE(kiocb->ki_cancel); | |
404 | do { | |
405 | if (!cancel || cancel == KIOCB_CANCELLED) | |
57282d8f | 406 | return -EINVAL; |
906b973c | 407 | |
0460fef2 KO |
408 | old = cancel; |
409 | cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED); | |
410 | } while (cancel != old); | |
906b973c | 411 | |
57282d8f | 412 | return cancel(kiocb); |
906b973c KO |
413 | } |
414 | ||
36f55889 KO |
415 | static void free_ioctx_rcu(struct rcu_head *head) |
416 | { | |
417 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); | |
e1bdd5f2 KO |
418 | |
419 | free_percpu(ctx->cpu); | |
36f55889 KO |
420 | kmem_cache_free(kioctx_cachep, ctx); |
421 | } | |
422 | ||
423 | /* | |
424 | * When this function runs, the kioctx has been removed from the "hash table" | |
425 | * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - | |
426 | * now it's safe to cancel any that need to be. | |
427 | */ | |
723be6e3 | 428 | static void free_ioctx(struct work_struct *work) |
36f55889 | 429 | { |
723be6e3 | 430 | struct kioctx *ctx = container_of(work, struct kioctx, free_work); |
3e845ce0 | 431 | struct aio_ring *ring; |
36f55889 | 432 | struct kiocb *req; |
5ffac122 KO |
433 | unsigned cpu, avail; |
434 | DEFINE_WAIT(wait); | |
36f55889 KO |
435 | |
436 | spin_lock_irq(&ctx->ctx_lock); | |
437 | ||
438 | while (!list_empty(&ctx->active_reqs)) { | |
439 | req = list_first_entry(&ctx->active_reqs, | |
440 | struct kiocb, ki_list); | |
441 | ||
442 | list_del_init(&req->ki_list); | |
bec68faa | 443 | kiocb_cancel(ctx, req); |
36f55889 KO |
444 | } |
445 | ||
446 | spin_unlock_irq(&ctx->ctx_lock); | |
447 | ||
e1bdd5f2 KO |
448 | for_each_possible_cpu(cpu) { |
449 | struct kioctx_cpu *kcpu = per_cpu_ptr(ctx->cpu, cpu); | |
450 | ||
451 | atomic_add(kcpu->reqs_available, &ctx->reqs_available); | |
452 | kcpu->reqs_available = 0; | |
453 | } | |
454 | ||
5ffac122 KO |
455 | while (1) { |
456 | prepare_to_wait(&ctx->wait, &wait, TASK_UNINTERRUPTIBLE); | |
3e845ce0 | 457 | |
5ffac122 KO |
458 | ring = kmap_atomic(ctx->ring_pages[0]); |
459 | avail = (ring->head <= ring->tail) | |
460 | ? ring->tail - ring->head | |
461 | : ctx->nr_events - ring->head + ring->tail; | |
3e845ce0 | 462 | |
34e83fc6 | 463 | atomic_add(avail, &ctx->reqs_available); |
5ffac122 KO |
464 | ring->head = ring->tail; |
465 | kunmap_atomic(ring); | |
466 | ||
467 | if (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1) | |
468 | break; | |
469 | ||
470 | schedule(); | |
3e845ce0 | 471 | } |
5ffac122 | 472 | finish_wait(&ctx->wait, &wait); |
3e845ce0 | 473 | |
34e83fc6 | 474 | WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr_events - 1); |
36f55889 KO |
475 | |
476 | aio_free_ring(ctx); | |
477 | ||
36f55889 KO |
478 | pr_debug("freeing %p\n", ctx); |
479 | ||
480 | /* | |
481 | * Here the call_rcu() is between the wait_event() for reqs_active to | |
482 | * hit 0, and freeing the ioctx. | |
483 | * | |
484 | * aio_complete() decrements reqs_active, but it has to touch the ioctx | |
485 | * after to issue a wakeup so we use rcu. | |
486 | */ | |
487 | call_rcu(&ctx->rcu_head, free_ioctx_rcu); | |
488 | } | |
489 | ||
723be6e3 | 490 | static void free_ioctx_ref(struct percpu_ref *ref) |
36f55889 | 491 | { |
723be6e3 KO |
492 | struct kioctx *ctx = container_of(ref, struct kioctx, users); |
493 | ||
494 | INIT_WORK(&ctx->free_work, free_ioctx); | |
495 | schedule_work(&ctx->free_work); | |
36f55889 KO |
496 | } |
497 | ||
db446a08 BL |
498 | static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) |
499 | { | |
500 | unsigned i, new_nr; | |
501 | struct kioctx_table *table, *old; | |
502 | struct aio_ring *ring; | |
503 | ||
504 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 505 | rcu_read_lock(); |
77d30b14 | 506 | table = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
507 | |
508 | while (1) { | |
509 | if (table) | |
510 | for (i = 0; i < table->nr; i++) | |
511 | if (!table->table[i]) { | |
512 | ctx->id = i; | |
513 | table->table[i] = ctx; | |
d9b2c871 | 514 | rcu_read_unlock(); |
db446a08 BL |
515 | spin_unlock(&mm->ioctx_lock); |
516 | ||
517 | ring = kmap_atomic(ctx->ring_pages[0]); | |
518 | ring->id = ctx->id; | |
519 | kunmap_atomic(ring); | |
520 | return 0; | |
521 | } | |
522 | ||
523 | new_nr = (table ? table->nr : 1) * 4; | |
524 | ||
d9b2c871 | 525 | rcu_read_unlock(); |
db446a08 BL |
526 | spin_unlock(&mm->ioctx_lock); |
527 | ||
528 | table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * | |
529 | new_nr, GFP_KERNEL); | |
530 | if (!table) | |
531 | return -ENOMEM; | |
532 | ||
533 | table->nr = new_nr; | |
534 | ||
535 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 536 | rcu_read_lock(); |
77d30b14 | 537 | old = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
538 | |
539 | if (!old) { | |
540 | rcu_assign_pointer(mm->ioctx_table, table); | |
541 | } else if (table->nr > old->nr) { | |
542 | memcpy(table->table, old->table, | |
543 | old->nr * sizeof(struct kioctx *)); | |
544 | ||
545 | rcu_assign_pointer(mm->ioctx_table, table); | |
546 | kfree_rcu(old, rcu); | |
547 | } else { | |
548 | kfree(table); | |
549 | table = old; | |
550 | } | |
551 | } | |
552 | } | |
553 | ||
1da177e4 LT |
554 | /* ioctx_alloc |
555 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. | |
556 | */ | |
557 | static struct kioctx *ioctx_alloc(unsigned nr_events) | |
558 | { | |
41003a7b | 559 | struct mm_struct *mm = current->mm; |
1da177e4 | 560 | struct kioctx *ctx; |
e23754f8 | 561 | int err = -ENOMEM; |
1da177e4 | 562 | |
e1bdd5f2 KO |
563 | /* |
564 | * We keep track of the number of available ringbuffer slots, to prevent | |
565 | * overflow (reqs_available), and we also use percpu counters for this. | |
566 | * | |
567 | * So since up to half the slots might be on other cpu's percpu counters | |
568 | * and unavailable, double nr_events so userspace sees what they | |
569 | * expected: additionally, we move req_batch slots to/from percpu | |
570 | * counters at a time, so make sure that isn't 0: | |
571 | */ | |
572 | nr_events = max(nr_events, num_possible_cpus() * 4); | |
573 | nr_events *= 2; | |
574 | ||
1da177e4 LT |
575 | /* Prevent overflows */ |
576 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || | |
577 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { | |
578 | pr_debug("ENOMEM: nr_events too high\n"); | |
579 | return ERR_PTR(-EINVAL); | |
580 | } | |
581 | ||
4cd81c3d | 582 | if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL)) |
1da177e4 LT |
583 | return ERR_PTR(-EAGAIN); |
584 | ||
c3762229 | 585 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
1da177e4 LT |
586 | if (!ctx) |
587 | return ERR_PTR(-ENOMEM); | |
588 | ||
1da177e4 | 589 | ctx->max_reqs = nr_events; |
1da177e4 | 590 | |
723be6e3 KO |
591 | if (percpu_ref_init(&ctx->users, free_ioctx_ref)) |
592 | goto out_freectx; | |
593 | ||
1da177e4 | 594 | spin_lock_init(&ctx->ctx_lock); |
0460fef2 | 595 | spin_lock_init(&ctx->completion_lock); |
58c85dc2 | 596 | mutex_init(&ctx->ring_lock); |
1da177e4 LT |
597 | init_waitqueue_head(&ctx->wait); |
598 | ||
599 | INIT_LIST_HEAD(&ctx->active_reqs); | |
1da177e4 | 600 | |
e1bdd5f2 KO |
601 | ctx->cpu = alloc_percpu(struct kioctx_cpu); |
602 | if (!ctx->cpu) | |
723be6e3 | 603 | goto out_freeref; |
1da177e4 | 604 | |
e1bdd5f2 KO |
605 | if (aio_setup_ring(ctx) < 0) |
606 | goto out_freepcpu; | |
607 | ||
34e83fc6 | 608 | atomic_set(&ctx->reqs_available, ctx->nr_events - 1); |
e1bdd5f2 | 609 | ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); |
6878ea72 BL |
610 | if (ctx->req_batch < 1) |
611 | ctx->req_batch = 1; | |
34e83fc6 | 612 | |
1da177e4 | 613 | /* limit the number of system wide aios */ |
9fa1cb39 | 614 | spin_lock(&aio_nr_lock); |
4cd81c3d | 615 | if (aio_nr + nr_events > (aio_max_nr * 2UL) || |
2dd542b7 | 616 | aio_nr + nr_events < aio_nr) { |
9fa1cb39 | 617 | spin_unlock(&aio_nr_lock); |
1da177e4 | 618 | goto out_cleanup; |
2dd542b7 AV |
619 | } |
620 | aio_nr += ctx->max_reqs; | |
9fa1cb39 | 621 | spin_unlock(&aio_nr_lock); |
1da177e4 | 622 | |
723be6e3 KO |
623 | percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ |
624 | ||
da90382c BL |
625 | err = ioctx_add_table(ctx, mm); |
626 | if (err) | |
627 | goto out_cleanup_put; | |
628 | ||
caf4167a | 629 | pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
58c85dc2 | 630 | ctx, ctx->user_id, mm, ctx->nr_events); |
1da177e4 LT |
631 | return ctx; |
632 | ||
da90382c BL |
633 | out_cleanup_put: |
634 | percpu_ref_put(&ctx->users); | |
1da177e4 | 635 | out_cleanup: |
e23754f8 AV |
636 | err = -EAGAIN; |
637 | aio_free_ring(ctx); | |
e1bdd5f2 KO |
638 | out_freepcpu: |
639 | free_percpu(ctx->cpu); | |
723be6e3 KO |
640 | out_freeref: |
641 | free_percpu(ctx->users.pcpu_count); | |
1da177e4 | 642 | out_freectx: |
5e9ae2e5 | 643 | put_aio_ring_file(ctx); |
1da177e4 | 644 | kmem_cache_free(kioctx_cachep, ctx); |
caf4167a | 645 | pr_debug("error allocating ioctx %d\n", err); |
e23754f8 | 646 | return ERR_PTR(err); |
1da177e4 LT |
647 | } |
648 | ||
36f55889 KO |
649 | /* kill_ioctx |
650 | * Cancels all outstanding aio requests on an aio context. Used | |
651 | * when the processes owning a context have all exited to encourage | |
652 | * the rapid destruction of the kioctx. | |
653 | */ | |
db446a08 | 654 | static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx) |
36f55889 KO |
655 | { |
656 | if (!atomic_xchg(&ctx->dead, 1)) { | |
db446a08 BL |
657 | struct kioctx_table *table; |
658 | ||
659 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 660 | rcu_read_lock(); |
77d30b14 | 661 | table = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
662 | |
663 | WARN_ON(ctx != table->table[ctx->id]); | |
664 | table->table[ctx->id] = NULL; | |
d9b2c871 | 665 | rcu_read_unlock(); |
db446a08 BL |
666 | spin_unlock(&mm->ioctx_lock); |
667 | ||
723be6e3 KO |
668 | /* percpu_ref_kill() will do the necessary call_rcu() */ |
669 | wake_up_all(&ctx->wait); | |
dee11c23 | 670 | |
36f55889 | 671 | /* |
4fcc712f KO |
672 | * It'd be more correct to do this in free_ioctx(), after all |
673 | * the outstanding kiocbs have finished - but by then io_destroy | |
674 | * has already returned, so io_setup() could potentially return | |
675 | * -EAGAIN with no ioctxs actually in use (as far as userspace | |
676 | * could tell). | |
36f55889 | 677 | */ |
4fcc712f KO |
678 | spin_lock(&aio_nr_lock); |
679 | BUG_ON(aio_nr - ctx->max_reqs > aio_nr); | |
680 | aio_nr -= ctx->max_reqs; | |
681 | spin_unlock(&aio_nr_lock); | |
682 | ||
683 | if (ctx->mmap_size) | |
684 | vm_munmap(ctx->mmap_base, ctx->mmap_size); | |
685 | ||
723be6e3 | 686 | percpu_ref_kill(&ctx->users); |
36f55889 | 687 | } |
1da177e4 LT |
688 | } |
689 | ||
690 | /* wait_on_sync_kiocb: | |
691 | * Waits on the given sync kiocb to complete. | |
692 | */ | |
57282d8f | 693 | ssize_t wait_on_sync_kiocb(struct kiocb *req) |
1da177e4 | 694 | { |
57282d8f | 695 | while (!req->ki_ctx) { |
1da177e4 | 696 | set_current_state(TASK_UNINTERRUPTIBLE); |
57282d8f | 697 | if (req->ki_ctx) |
1da177e4 | 698 | break; |
41d10da3 | 699 | io_schedule(); |
1da177e4 LT |
700 | } |
701 | __set_current_state(TASK_RUNNING); | |
57282d8f | 702 | return req->ki_user_data; |
1da177e4 | 703 | } |
385773e0 | 704 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
1da177e4 | 705 | |
36f55889 KO |
706 | /* |
707 | * exit_aio: called when the last user of mm goes away. At this point, there is | |
708 | * no way for any new requests to be submited or any of the io_* syscalls to be | |
709 | * called on the context. | |
710 | * | |
711 | * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on | |
712 | * them. | |
1da177e4 | 713 | */ |
fc9b52cd | 714 | void exit_aio(struct mm_struct *mm) |
1da177e4 | 715 | { |
db446a08 | 716 | struct kioctx_table *table; |
abf137dd | 717 | struct kioctx *ctx; |
db446a08 BL |
718 | unsigned i = 0; |
719 | ||
720 | while (1) { | |
721 | rcu_read_lock(); | |
722 | table = rcu_dereference(mm->ioctx_table); | |
723 | ||
724 | do { | |
725 | if (!table || i >= table->nr) { | |
726 | rcu_read_unlock(); | |
727 | rcu_assign_pointer(mm->ioctx_table, NULL); | |
728 | if (table) | |
729 | kfree(table); | |
730 | return; | |
731 | } | |
732 | ||
733 | ctx = table->table[i++]; | |
734 | } while (!ctx); | |
735 | ||
736 | rcu_read_unlock(); | |
abf137dd | 737 | |
936af157 AV |
738 | /* |
739 | * We don't need to bother with munmap() here - | |
740 | * exit_mmap(mm) is coming and it'll unmap everything. | |
741 | * Since aio_free_ring() uses non-zero ->mmap_size | |
742 | * as indicator that it needs to unmap the area, | |
743 | * just set it to 0; aio_free_ring() is the only | |
744 | * place that uses ->mmap_size, so it's safe. | |
936af157 | 745 | */ |
58c85dc2 | 746 | ctx->mmap_size = 0; |
36f55889 | 747 | |
db446a08 | 748 | kill_ioctx(mm, ctx); |
1da177e4 LT |
749 | } |
750 | } | |
751 | ||
e1bdd5f2 KO |
752 | static void put_reqs_available(struct kioctx *ctx, unsigned nr) |
753 | { | |
754 | struct kioctx_cpu *kcpu; | |
755 | ||
756 | preempt_disable(); | |
757 | kcpu = this_cpu_ptr(ctx->cpu); | |
758 | ||
759 | kcpu->reqs_available += nr; | |
760 | while (kcpu->reqs_available >= ctx->req_batch * 2) { | |
761 | kcpu->reqs_available -= ctx->req_batch; | |
762 | atomic_add(ctx->req_batch, &ctx->reqs_available); | |
763 | } | |
764 | ||
765 | preempt_enable(); | |
766 | } | |
767 | ||
768 | static bool get_reqs_available(struct kioctx *ctx) | |
769 | { | |
770 | struct kioctx_cpu *kcpu; | |
771 | bool ret = false; | |
772 | ||
773 | preempt_disable(); | |
774 | kcpu = this_cpu_ptr(ctx->cpu); | |
775 | ||
776 | if (!kcpu->reqs_available) { | |
777 | int old, avail = atomic_read(&ctx->reqs_available); | |
778 | ||
779 | do { | |
780 | if (avail < ctx->req_batch) | |
781 | goto out; | |
782 | ||
783 | old = avail; | |
784 | avail = atomic_cmpxchg(&ctx->reqs_available, | |
785 | avail, avail - ctx->req_batch); | |
786 | } while (avail != old); | |
787 | ||
788 | kcpu->reqs_available += ctx->req_batch; | |
789 | } | |
790 | ||
791 | ret = true; | |
792 | kcpu->reqs_available--; | |
793 | out: | |
794 | preempt_enable(); | |
795 | return ret; | |
796 | } | |
797 | ||
1da177e4 | 798 | /* aio_get_req |
57282d8f KO |
799 | * Allocate a slot for an aio request. |
800 | * Returns NULL if no requests are free. | |
1da177e4 | 801 | */ |
a1c8eae7 | 802 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
1da177e4 | 803 | { |
a1c8eae7 KO |
804 | struct kiocb *req; |
805 | ||
e1bdd5f2 | 806 | if (!get_reqs_available(ctx)) |
a1c8eae7 KO |
807 | return NULL; |
808 | ||
0460fef2 | 809 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); |
1da177e4 | 810 | if (unlikely(!req)) |
a1c8eae7 | 811 | goto out_put; |
1da177e4 | 812 | |
1da177e4 | 813 | req->ki_ctx = ctx; |
080d676d | 814 | return req; |
a1c8eae7 | 815 | out_put: |
e1bdd5f2 | 816 | put_reqs_available(ctx, 1); |
a1c8eae7 | 817 | return NULL; |
1da177e4 LT |
818 | } |
819 | ||
11599eba | 820 | static void kiocb_free(struct kiocb *req) |
1da177e4 | 821 | { |
1d98ebfc KO |
822 | if (req->ki_filp) |
823 | fput(req->ki_filp); | |
13389010 DL |
824 | if (req->ki_eventfd != NULL) |
825 | eventfd_ctx_put(req->ki_eventfd); | |
1da177e4 | 826 | kmem_cache_free(kiocb_cachep, req); |
1da177e4 LT |
827 | } |
828 | ||
d5470b59 | 829 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
1da177e4 | 830 | { |
db446a08 | 831 | struct aio_ring __user *ring = (void __user *)ctx_id; |
abf137dd | 832 | struct mm_struct *mm = current->mm; |
65c24491 | 833 | struct kioctx *ctx, *ret = NULL; |
db446a08 BL |
834 | struct kioctx_table *table; |
835 | unsigned id; | |
836 | ||
837 | if (get_user(id, &ring->id)) | |
838 | return NULL; | |
1da177e4 | 839 | |
abf137dd | 840 | rcu_read_lock(); |
db446a08 | 841 | table = rcu_dereference(mm->ioctx_table); |
abf137dd | 842 | |
db446a08 BL |
843 | if (!table || id >= table->nr) |
844 | goto out; | |
1da177e4 | 845 | |
db446a08 | 846 | ctx = table->table[id]; |
f30d704f | 847 | if (ctx && ctx->user_id == ctx_id) { |
db446a08 BL |
848 | percpu_ref_get(&ctx->users); |
849 | ret = ctx; | |
850 | } | |
851 | out: | |
abf137dd | 852 | rcu_read_unlock(); |
65c24491 | 853 | return ret; |
1da177e4 LT |
854 | } |
855 | ||
1da177e4 LT |
856 | /* aio_complete |
857 | * Called when the io request on the given iocb is complete. | |
1da177e4 | 858 | */ |
2d68449e | 859 | void aio_complete(struct kiocb *iocb, long res, long res2) |
1da177e4 LT |
860 | { |
861 | struct kioctx *ctx = iocb->ki_ctx; | |
1da177e4 | 862 | struct aio_ring *ring; |
21b40200 | 863 | struct io_event *ev_page, *event; |
1da177e4 | 864 | unsigned long flags; |
21b40200 | 865 | unsigned tail, pos; |
1da177e4 | 866 | |
20dcae32 ZB |
867 | /* |
868 | * Special case handling for sync iocbs: | |
869 | * - events go directly into the iocb for fast handling | |
870 | * - the sync task with the iocb in its stack holds the single iocb | |
871 | * ref, no other paths have a way to get another ref | |
872 | * - the sync task helpfully left a reference to itself in the iocb | |
1da177e4 LT |
873 | */ |
874 | if (is_sync_kiocb(iocb)) { | |
1da177e4 | 875 | iocb->ki_user_data = res; |
57282d8f KO |
876 | smp_wmb(); |
877 | iocb->ki_ctx = ERR_PTR(-EXDEV); | |
1da177e4 | 878 | wake_up_process(iocb->ki_obj.tsk); |
2d68449e | 879 | return; |
1da177e4 LT |
880 | } |
881 | ||
36f55889 | 882 | /* |
36f55889 | 883 | * Take rcu_read_lock() in case the kioctx is being destroyed, as we |
34e83fc6 | 884 | * need to issue a wakeup after incrementing reqs_available. |
1da177e4 | 885 | */ |
36f55889 | 886 | rcu_read_lock(); |
1da177e4 | 887 | |
0460fef2 KO |
888 | if (iocb->ki_list.next) { |
889 | unsigned long flags; | |
890 | ||
891 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
892 | list_del(&iocb->ki_list); | |
893 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
894 | } | |
11599eba | 895 | |
0460fef2 KO |
896 | /* |
897 | * Add a completion event to the ring buffer. Must be done holding | |
4b30f07e | 898 | * ctx->completion_lock to prevent other code from messing with the tail |
0460fef2 KO |
899 | * pointer since we might be called from irq context. |
900 | */ | |
901 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
902 | ||
58c85dc2 | 903 | tail = ctx->tail; |
21b40200 KO |
904 | pos = tail + AIO_EVENTS_OFFSET; |
905 | ||
58c85dc2 | 906 | if (++tail >= ctx->nr_events) |
4bf69b2a | 907 | tail = 0; |
1da177e4 | 908 | |
58c85dc2 | 909 | ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
910 | event = ev_page + pos % AIO_EVENTS_PER_PAGE; |
911 | ||
1da177e4 LT |
912 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
913 | event->data = iocb->ki_user_data; | |
914 | event->res = res; | |
915 | event->res2 = res2; | |
916 | ||
21b40200 | 917 | kunmap_atomic(ev_page); |
58c85dc2 | 918 | flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
919 | |
920 | pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n", | |
caf4167a KO |
921 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
922 | res, res2); | |
1da177e4 LT |
923 | |
924 | /* after flagging the request as done, we | |
925 | * must never even look at it again | |
926 | */ | |
927 | smp_wmb(); /* make event visible before updating tail */ | |
928 | ||
58c85dc2 | 929 | ctx->tail = tail; |
1da177e4 | 930 | |
58c85dc2 | 931 | ring = kmap_atomic(ctx->ring_pages[0]); |
21b40200 | 932 | ring->tail = tail; |
e8e3c3d6 | 933 | kunmap_atomic(ring); |
58c85dc2 | 934 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 | 935 | |
0460fef2 KO |
936 | spin_unlock_irqrestore(&ctx->completion_lock, flags); |
937 | ||
21b40200 | 938 | pr_debug("added to ring %p at [%u]\n", iocb, tail); |
8d1c98b0 DL |
939 | |
940 | /* | |
941 | * Check if the user asked us to deliver the result through an | |
942 | * eventfd. The eventfd_signal() function is safe to be called | |
943 | * from IRQ context. | |
944 | */ | |
87c3a86e | 945 | if (iocb->ki_eventfd != NULL) |
8d1c98b0 DL |
946 | eventfd_signal(iocb->ki_eventfd, 1); |
947 | ||
1da177e4 | 948 | /* everything turned out well, dispose of the aiocb. */ |
57282d8f | 949 | kiocb_free(iocb); |
1da177e4 | 950 | |
6cb2a210 QB |
951 | /* |
952 | * We have to order our ring_info tail store above and test | |
953 | * of the wait list below outside the wait lock. This is | |
954 | * like in wake_up_bit() where clearing a bit has to be | |
955 | * ordered with the unlocked test. | |
956 | */ | |
957 | smp_mb(); | |
958 | ||
1da177e4 LT |
959 | if (waitqueue_active(&ctx->wait)) |
960 | wake_up(&ctx->wait); | |
961 | ||
36f55889 | 962 | rcu_read_unlock(); |
1da177e4 | 963 | } |
385773e0 | 964 | EXPORT_SYMBOL(aio_complete); |
1da177e4 | 965 | |
a31ad380 KO |
966 | /* aio_read_events |
967 | * Pull an event off of the ioctx's event ring. Returns the number of | |
968 | * events fetched | |
1da177e4 | 969 | */ |
a31ad380 KO |
970 | static long aio_read_events_ring(struct kioctx *ctx, |
971 | struct io_event __user *event, long nr) | |
1da177e4 | 972 | { |
1da177e4 | 973 | struct aio_ring *ring; |
5ffac122 | 974 | unsigned head, tail, pos; |
a31ad380 KO |
975 | long ret = 0; |
976 | int copy_ret; | |
977 | ||
58c85dc2 | 978 | mutex_lock(&ctx->ring_lock); |
1da177e4 | 979 | |
58c85dc2 | 980 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 981 | head = ring->head; |
5ffac122 | 982 | tail = ring->tail; |
a31ad380 KO |
983 | kunmap_atomic(ring); |
984 | ||
5ffac122 | 985 | pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); |
1da177e4 | 986 | |
5ffac122 | 987 | if (head == tail) |
1da177e4 LT |
988 | goto out; |
989 | ||
a31ad380 KO |
990 | while (ret < nr) { |
991 | long avail; | |
992 | struct io_event *ev; | |
993 | struct page *page; | |
994 | ||
5ffac122 KO |
995 | avail = (head <= tail ? tail : ctx->nr_events) - head; |
996 | if (head == tail) | |
a31ad380 KO |
997 | break; |
998 | ||
999 | avail = min(avail, nr - ret); | |
1000 | avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - | |
1001 | ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE)); | |
1002 | ||
1003 | pos = head + AIO_EVENTS_OFFSET; | |
58c85dc2 | 1004 | page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; |
a31ad380 KO |
1005 | pos %= AIO_EVENTS_PER_PAGE; |
1006 | ||
1007 | ev = kmap(page); | |
1008 | copy_ret = copy_to_user(event + ret, ev + pos, | |
1009 | sizeof(*ev) * avail); | |
1010 | kunmap(page); | |
1011 | ||
1012 | if (unlikely(copy_ret)) { | |
1013 | ret = -EFAULT; | |
1014 | goto out; | |
1015 | } | |
1016 | ||
1017 | ret += avail; | |
1018 | head += avail; | |
58c85dc2 | 1019 | head %= ctx->nr_events; |
1da177e4 | 1020 | } |
1da177e4 | 1021 | |
58c85dc2 | 1022 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 1023 | ring->head = head; |
91d80a84 | 1024 | kunmap_atomic(ring); |
58c85dc2 | 1025 | flush_dcache_page(ctx->ring_pages[0]); |
a31ad380 | 1026 | |
5ffac122 | 1027 | pr_debug("%li h%u t%u\n", ret, head, tail); |
3e845ce0 | 1028 | |
e1bdd5f2 | 1029 | put_reqs_available(ctx, ret); |
a31ad380 | 1030 | out: |
58c85dc2 | 1031 | mutex_unlock(&ctx->ring_lock); |
a31ad380 | 1032 | |
1da177e4 LT |
1033 | return ret; |
1034 | } | |
1035 | ||
a31ad380 KO |
1036 | static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, |
1037 | struct io_event __user *event, long *i) | |
1da177e4 | 1038 | { |
a31ad380 | 1039 | long ret = aio_read_events_ring(ctx, event + *i, nr - *i); |
1da177e4 | 1040 | |
a31ad380 KO |
1041 | if (ret > 0) |
1042 | *i += ret; | |
1da177e4 | 1043 | |
a31ad380 KO |
1044 | if (unlikely(atomic_read(&ctx->dead))) |
1045 | ret = -EINVAL; | |
1da177e4 | 1046 | |
a31ad380 KO |
1047 | if (!*i) |
1048 | *i = ret; | |
1da177e4 | 1049 | |
a31ad380 | 1050 | return ret < 0 || *i >= min_nr; |
1da177e4 LT |
1051 | } |
1052 | ||
a31ad380 | 1053 | static long read_events(struct kioctx *ctx, long min_nr, long nr, |
1da177e4 LT |
1054 | struct io_event __user *event, |
1055 | struct timespec __user *timeout) | |
1056 | { | |
a31ad380 KO |
1057 | ktime_t until = { .tv64 = KTIME_MAX }; |
1058 | long ret = 0; | |
1da177e4 | 1059 | |
1da177e4 LT |
1060 | if (timeout) { |
1061 | struct timespec ts; | |
a31ad380 | 1062 | |
1da177e4 | 1063 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
a31ad380 | 1064 | return -EFAULT; |
1da177e4 | 1065 | |
a31ad380 | 1066 | until = timespec_to_ktime(ts); |
1da177e4 LT |
1067 | } |
1068 | ||
a31ad380 KO |
1069 | /* |
1070 | * Note that aio_read_events() is being called as the conditional - i.e. | |
1071 | * we're calling it after prepare_to_wait() has set task state to | |
1072 | * TASK_INTERRUPTIBLE. | |
1073 | * | |
1074 | * But aio_read_events() can block, and if it blocks it's going to flip | |
1075 | * the task state back to TASK_RUNNING. | |
1076 | * | |
1077 | * This should be ok, provided it doesn't flip the state back to | |
1078 | * TASK_RUNNING and return 0 too much - that causes us to spin. That | |
1079 | * will only happen if the mutex_lock() call blocks, and we then find | |
1080 | * the ringbuffer empty. So in practice we should be ok, but it's | |
1081 | * something to be aware of when touching this code. | |
1082 | */ | |
1083 | wait_event_interruptible_hrtimeout(ctx->wait, | |
1084 | aio_read_events(ctx, min_nr, nr, event, &ret), until); | |
1da177e4 | 1085 | |
a31ad380 KO |
1086 | if (!ret && signal_pending(current)) |
1087 | ret = -EINTR; | |
1da177e4 | 1088 | |
a31ad380 | 1089 | return ret; |
1da177e4 LT |
1090 | } |
1091 | ||
1da177e4 LT |
1092 | /* sys_io_setup: |
1093 | * Create an aio_context capable of receiving at least nr_events. | |
1094 | * ctxp must not point to an aio_context that already exists, and | |
1095 | * must be initialized to 0 prior to the call. On successful | |
1096 | * creation of the aio_context, *ctxp is filled in with the resulting | |
1097 | * handle. May fail with -EINVAL if *ctxp is not initialized, | |
1098 | * if the specified nr_events exceeds internal limits. May fail | |
1099 | * with -EAGAIN if the specified nr_events exceeds the user's limit | |
1100 | * of available events. May fail with -ENOMEM if insufficient kernel | |
1101 | * resources are available. May fail with -EFAULT if an invalid | |
1102 | * pointer is passed for ctxp. Will fail with -ENOSYS if not | |
1103 | * implemented. | |
1104 | */ | |
002c8976 | 1105 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1da177e4 LT |
1106 | { |
1107 | struct kioctx *ioctx = NULL; | |
1108 | unsigned long ctx; | |
1109 | long ret; | |
1110 | ||
1111 | ret = get_user(ctx, ctxp); | |
1112 | if (unlikely(ret)) | |
1113 | goto out; | |
1114 | ||
1115 | ret = -EINVAL; | |
d55b5fda ZB |
1116 | if (unlikely(ctx || nr_events == 0)) { |
1117 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", | |
1118 | ctx, nr_events); | |
1da177e4 LT |
1119 | goto out; |
1120 | } | |
1121 | ||
1122 | ioctx = ioctx_alloc(nr_events); | |
1123 | ret = PTR_ERR(ioctx); | |
1124 | if (!IS_ERR(ioctx)) { | |
1125 | ret = put_user(ioctx->user_id, ctxp); | |
a2e1859a | 1126 | if (ret) |
db446a08 | 1127 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1128 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1129 | } |
1130 | ||
1131 | out: | |
1132 | return ret; | |
1133 | } | |
1134 | ||
1135 | /* sys_io_destroy: | |
1136 | * Destroy the aio_context specified. May cancel any outstanding | |
1137 | * AIOs and block on completion. Will fail with -ENOSYS if not | |
642b5123 | 1138 | * implemented. May fail with -EINVAL if the context pointed to |
1da177e4 LT |
1139 | * is invalid. |
1140 | */ | |
002c8976 | 1141 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1da177e4 LT |
1142 | { |
1143 | struct kioctx *ioctx = lookup_ioctx(ctx); | |
1144 | if (likely(NULL != ioctx)) { | |
db446a08 | 1145 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1146 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1147 | return 0; |
1148 | } | |
1149 | pr_debug("EINVAL: io_destroy: invalid context id\n"); | |
1150 | return -EINVAL; | |
1151 | } | |
1152 | ||
41ef4eb8 KO |
1153 | typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *, |
1154 | unsigned long, loff_t); | |
1155 | ||
8bc92afc KO |
1156 | static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb, |
1157 | int rw, char __user *buf, | |
1158 | unsigned long *nr_segs, | |
1159 | struct iovec **iovec, | |
1160 | bool compat) | |
eed4e51f BP |
1161 | { |
1162 | ssize_t ret; | |
1163 | ||
8bc92afc | 1164 | *nr_segs = kiocb->ki_nbytes; |
41ef4eb8 | 1165 | |
9d85cba7 JM |
1166 | #ifdef CONFIG_COMPAT |
1167 | if (compat) | |
41ef4eb8 | 1168 | ret = compat_rw_copy_check_uvector(rw, |
8bc92afc KO |
1169 | (struct compat_iovec __user *)buf, |
1170 | *nr_segs, 1, *iovec, iovec); | |
9d85cba7 JM |
1171 | else |
1172 | #endif | |
41ef4eb8 | 1173 | ret = rw_copy_check_uvector(rw, |
8bc92afc KO |
1174 | (struct iovec __user *)buf, |
1175 | *nr_segs, 1, *iovec, iovec); | |
eed4e51f | 1176 | if (ret < 0) |
41ef4eb8 | 1177 | return ret; |
a70b52ec | 1178 | |
41ef4eb8 | 1179 | /* ki_nbytes now reflect bytes instead of segs */ |
eed4e51f | 1180 | kiocb->ki_nbytes = ret; |
41ef4eb8 | 1181 | return 0; |
eed4e51f BP |
1182 | } |
1183 | ||
8bc92afc KO |
1184 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb, |
1185 | int rw, char __user *buf, | |
1186 | unsigned long *nr_segs, | |
1187 | struct iovec *iovec) | |
eed4e51f | 1188 | { |
8bc92afc | 1189 | if (unlikely(!access_ok(!rw, buf, kiocb->ki_nbytes))) |
41ef4eb8 | 1190 | return -EFAULT; |
a70b52ec | 1191 | |
8bc92afc KO |
1192 | iovec->iov_base = buf; |
1193 | iovec->iov_len = kiocb->ki_nbytes; | |
1194 | *nr_segs = 1; | |
eed4e51f BP |
1195 | return 0; |
1196 | } | |
1197 | ||
1da177e4 LT |
1198 | /* |
1199 | * aio_setup_iocb: | |
1200 | * Performs the initial checks and aio retry method | |
1201 | * setup for the kiocb at the time of io submission. | |
1202 | */ | |
8bc92afc KO |
1203 | static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode, |
1204 | char __user *buf, bool compat) | |
1da177e4 | 1205 | { |
41ef4eb8 KO |
1206 | struct file *file = req->ki_filp; |
1207 | ssize_t ret; | |
8bc92afc | 1208 | unsigned long nr_segs; |
41ef4eb8 KO |
1209 | int rw; |
1210 | fmode_t mode; | |
1211 | aio_rw_op *rw_op; | |
8bc92afc | 1212 | struct iovec inline_vec, *iovec = &inline_vec; |
1da177e4 | 1213 | |
8bc92afc | 1214 | switch (opcode) { |
1da177e4 | 1215 | case IOCB_CMD_PREAD: |
eed4e51f | 1216 | case IOCB_CMD_PREADV: |
41ef4eb8 KO |
1217 | mode = FMODE_READ; |
1218 | rw = READ; | |
1219 | rw_op = file->f_op->aio_read; | |
1220 | goto rw_common; | |
1221 | ||
1222 | case IOCB_CMD_PWRITE: | |
eed4e51f | 1223 | case IOCB_CMD_PWRITEV: |
41ef4eb8 KO |
1224 | mode = FMODE_WRITE; |
1225 | rw = WRITE; | |
1226 | rw_op = file->f_op->aio_write; | |
1227 | goto rw_common; | |
1228 | rw_common: | |
1229 | if (unlikely(!(file->f_mode & mode))) | |
1230 | return -EBADF; | |
1231 | ||
1232 | if (!rw_op) | |
1233 | return -EINVAL; | |
1234 | ||
8bc92afc KO |
1235 | ret = (opcode == IOCB_CMD_PREADV || |
1236 | opcode == IOCB_CMD_PWRITEV) | |
1237 | ? aio_setup_vectored_rw(req, rw, buf, &nr_segs, | |
1238 | &iovec, compat) | |
1239 | : aio_setup_single_vector(req, rw, buf, &nr_segs, | |
1240 | iovec); | |
eed4e51f | 1241 | if (ret) |
41ef4eb8 KO |
1242 | return ret; |
1243 | ||
1244 | ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes); | |
8bc92afc KO |
1245 | if (ret < 0) { |
1246 | if (iovec != &inline_vec) | |
1247 | kfree(iovec); | |
41ef4eb8 | 1248 | return ret; |
8bc92afc | 1249 | } |
41ef4eb8 KO |
1250 | |
1251 | req->ki_nbytes = ret; | |
41ef4eb8 | 1252 | |
73a7075e KO |
1253 | /* XXX: move/kill - rw_verify_area()? */ |
1254 | /* This matches the pread()/pwrite() logic */ | |
1255 | if (req->ki_pos < 0) { | |
1256 | ret = -EINVAL; | |
1257 | break; | |
1258 | } | |
1259 | ||
1260 | if (rw == WRITE) | |
1261 | file_start_write(file); | |
1262 | ||
8bc92afc | 1263 | ret = rw_op(req, iovec, nr_segs, req->ki_pos); |
73a7075e KO |
1264 | |
1265 | if (rw == WRITE) | |
1266 | file_end_write(file); | |
1da177e4 | 1267 | break; |
41ef4eb8 | 1268 | |
1da177e4 | 1269 | case IOCB_CMD_FDSYNC: |
41ef4eb8 KO |
1270 | if (!file->f_op->aio_fsync) |
1271 | return -EINVAL; | |
1272 | ||
1273 | ret = file->f_op->aio_fsync(req, 1); | |
1da177e4 | 1274 | break; |
41ef4eb8 | 1275 | |
1da177e4 | 1276 | case IOCB_CMD_FSYNC: |
41ef4eb8 KO |
1277 | if (!file->f_op->aio_fsync) |
1278 | return -EINVAL; | |
1279 | ||
1280 | ret = file->f_op->aio_fsync(req, 0); | |
1da177e4 | 1281 | break; |
41ef4eb8 | 1282 | |
1da177e4 | 1283 | default: |
caf4167a | 1284 | pr_debug("EINVAL: no operation provided\n"); |
41ef4eb8 | 1285 | return -EINVAL; |
1da177e4 LT |
1286 | } |
1287 | ||
8bc92afc KO |
1288 | if (iovec != &inline_vec) |
1289 | kfree(iovec); | |
1290 | ||
41ef4eb8 KO |
1291 | if (ret != -EIOCBQUEUED) { |
1292 | /* | |
1293 | * There's no easy way to restart the syscall since other AIO's | |
1294 | * may be already running. Just fail this IO with EINTR. | |
1295 | */ | |
1296 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || | |
1297 | ret == -ERESTARTNOHAND || | |
1298 | ret == -ERESTART_RESTARTBLOCK)) | |
1299 | ret = -EINTR; | |
1300 | aio_complete(req, ret, 0); | |
1301 | } | |
1da177e4 LT |
1302 | |
1303 | return 0; | |
1304 | } | |
1305 | ||
d5470b59 | 1306 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
a1c8eae7 | 1307 | struct iocb *iocb, bool compat) |
1da177e4 LT |
1308 | { |
1309 | struct kiocb *req; | |
1da177e4 LT |
1310 | ssize_t ret; |
1311 | ||
1312 | /* enforce forwards compatibility on users */ | |
9c3060be | 1313 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
caf4167a | 1314 | pr_debug("EINVAL: reserve field set\n"); |
1da177e4 LT |
1315 | return -EINVAL; |
1316 | } | |
1317 | ||
1318 | /* prevent overflows */ | |
1319 | if (unlikely( | |
1320 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || | |
1321 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || | |
1322 | ((ssize_t)iocb->aio_nbytes < 0) | |
1323 | )) { | |
1324 | pr_debug("EINVAL: io_submit: overflow check\n"); | |
1325 | return -EINVAL; | |
1326 | } | |
1327 | ||
41ef4eb8 | 1328 | req = aio_get_req(ctx); |
1d98ebfc | 1329 | if (unlikely(!req)) |
1da177e4 | 1330 | return -EAGAIN; |
1d98ebfc KO |
1331 | |
1332 | req->ki_filp = fget(iocb->aio_fildes); | |
1333 | if (unlikely(!req->ki_filp)) { | |
1334 | ret = -EBADF; | |
1335 | goto out_put_req; | |
1da177e4 | 1336 | } |
1d98ebfc | 1337 | |
9c3060be DL |
1338 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1339 | /* | |
1340 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an | |
1341 | * instance of the file* now. The file descriptor must be | |
1342 | * an eventfd() fd, and will be signaled for each completed | |
1343 | * event using the eventfd_signal() function. | |
1344 | */ | |
13389010 | 1345 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
801678c5 | 1346 | if (IS_ERR(req->ki_eventfd)) { |
9c3060be | 1347 | ret = PTR_ERR(req->ki_eventfd); |
87c3a86e | 1348 | req->ki_eventfd = NULL; |
9c3060be DL |
1349 | goto out_put_req; |
1350 | } | |
1351 | } | |
1da177e4 | 1352 | |
8a660890 | 1353 | ret = put_user(KIOCB_KEY, &user_iocb->aio_key); |
1da177e4 | 1354 | if (unlikely(ret)) { |
caf4167a | 1355 | pr_debug("EFAULT: aio_key\n"); |
1da177e4 LT |
1356 | goto out_put_req; |
1357 | } | |
1358 | ||
1359 | req->ki_obj.user = user_iocb; | |
1360 | req->ki_user_data = iocb->aio_data; | |
1361 | req->ki_pos = iocb->aio_offset; | |
73a7075e | 1362 | req->ki_nbytes = iocb->aio_nbytes; |
1da177e4 | 1363 | |
8bc92afc KO |
1364 | ret = aio_run_iocb(req, iocb->aio_lio_opcode, |
1365 | (char __user *)(unsigned long)iocb->aio_buf, | |
1366 | compat); | |
41003a7b | 1367 | if (ret) |
7137c6bd | 1368 | goto out_put_req; |
41003a7b | 1369 | |
1da177e4 | 1370 | return 0; |
1da177e4 | 1371 | out_put_req: |
e1bdd5f2 | 1372 | put_reqs_available(ctx, 1); |
57282d8f | 1373 | kiocb_free(req); |
1da177e4 LT |
1374 | return ret; |
1375 | } | |
1376 | ||
9d85cba7 JM |
1377 | long do_io_submit(aio_context_t ctx_id, long nr, |
1378 | struct iocb __user *__user *iocbpp, bool compat) | |
1da177e4 LT |
1379 | { |
1380 | struct kioctx *ctx; | |
1381 | long ret = 0; | |
080d676d | 1382 | int i = 0; |
9f5b9425 | 1383 | struct blk_plug plug; |
1da177e4 LT |
1384 | |
1385 | if (unlikely(nr < 0)) | |
1386 | return -EINVAL; | |
1387 | ||
75e1c70f JM |
1388 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1389 | nr = LONG_MAX/sizeof(*iocbpp); | |
1390 | ||
1da177e4 LT |
1391 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1392 | return -EFAULT; | |
1393 | ||
1394 | ctx = lookup_ioctx(ctx_id); | |
1395 | if (unlikely(!ctx)) { | |
caf4167a | 1396 | pr_debug("EINVAL: invalid context id\n"); |
1da177e4 LT |
1397 | return -EINVAL; |
1398 | } | |
1399 | ||
9f5b9425 SL |
1400 | blk_start_plug(&plug); |
1401 | ||
1da177e4 LT |
1402 | /* |
1403 | * AKPM: should this return a partial result if some of the IOs were | |
1404 | * successfully submitted? | |
1405 | */ | |
1406 | for (i=0; i<nr; i++) { | |
1407 | struct iocb __user *user_iocb; | |
1408 | struct iocb tmp; | |
1409 | ||
1410 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { | |
1411 | ret = -EFAULT; | |
1412 | break; | |
1413 | } | |
1414 | ||
1415 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { | |
1416 | ret = -EFAULT; | |
1417 | break; | |
1418 | } | |
1419 | ||
a1c8eae7 | 1420 | ret = io_submit_one(ctx, user_iocb, &tmp, compat); |
1da177e4 LT |
1421 | if (ret) |
1422 | break; | |
1423 | } | |
9f5b9425 | 1424 | blk_finish_plug(&plug); |
1da177e4 | 1425 | |
723be6e3 | 1426 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1427 | return i ? i : ret; |
1428 | } | |
1429 | ||
9d85cba7 JM |
1430 | /* sys_io_submit: |
1431 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns | |
1432 | * the number of iocbs queued. May return -EINVAL if the aio_context | |
1433 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at | |
1434 | * *iocbpp[0] is not properly initialized, if the operation specified | |
1435 | * is invalid for the file descriptor in the iocb. May fail with | |
1436 | * -EFAULT if any of the data structures point to invalid data. May | |
1437 | * fail with -EBADF if the file descriptor specified in the first | |
1438 | * iocb is invalid. May fail with -EAGAIN if insufficient resources | |
1439 | * are available to queue any iocbs. Will return 0 if nr is 0. Will | |
1440 | * fail with -ENOSYS if not implemented. | |
1441 | */ | |
1442 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, | |
1443 | struct iocb __user * __user *, iocbpp) | |
1444 | { | |
1445 | return do_io_submit(ctx_id, nr, iocbpp, 0); | |
1446 | } | |
1447 | ||
1da177e4 LT |
1448 | /* lookup_kiocb |
1449 | * Finds a given iocb for cancellation. | |
1da177e4 | 1450 | */ |
25ee7e38 AB |
1451 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1452 | u32 key) | |
1da177e4 LT |
1453 | { |
1454 | struct list_head *pos; | |
d00689af ZB |
1455 | |
1456 | assert_spin_locked(&ctx->ctx_lock); | |
1457 | ||
8a660890 KO |
1458 | if (key != KIOCB_KEY) |
1459 | return NULL; | |
1460 | ||
1da177e4 LT |
1461 | /* TODO: use a hash or array, this sucks. */ |
1462 | list_for_each(pos, &ctx->active_reqs) { | |
1463 | struct kiocb *kiocb = list_kiocb(pos); | |
8a660890 | 1464 | if (kiocb->ki_obj.user == iocb) |
1da177e4 LT |
1465 | return kiocb; |
1466 | } | |
1467 | return NULL; | |
1468 | } | |
1469 | ||
1470 | /* sys_io_cancel: | |
1471 | * Attempts to cancel an iocb previously passed to io_submit. If | |
1472 | * the operation is successfully cancelled, the resulting event is | |
1473 | * copied into the memory pointed to by result without being placed | |
1474 | * into the completion queue and 0 is returned. May fail with | |
1475 | * -EFAULT if any of the data structures pointed to are invalid. | |
1476 | * May fail with -EINVAL if aio_context specified by ctx_id is | |
1477 | * invalid. May fail with -EAGAIN if the iocb specified was not | |
1478 | * cancelled. Will fail with -ENOSYS if not implemented. | |
1479 | */ | |
002c8976 HC |
1480 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1481 | struct io_event __user *, result) | |
1da177e4 | 1482 | { |
1da177e4 LT |
1483 | struct kioctx *ctx; |
1484 | struct kiocb *kiocb; | |
1485 | u32 key; | |
1486 | int ret; | |
1487 | ||
1488 | ret = get_user(key, &iocb->aio_key); | |
1489 | if (unlikely(ret)) | |
1490 | return -EFAULT; | |
1491 | ||
1492 | ctx = lookup_ioctx(ctx_id); | |
1493 | if (unlikely(!ctx)) | |
1494 | return -EINVAL; | |
1495 | ||
1496 | spin_lock_irq(&ctx->ctx_lock); | |
906b973c | 1497 | |
1da177e4 | 1498 | kiocb = lookup_kiocb(ctx, iocb, key); |
906b973c | 1499 | if (kiocb) |
bec68faa | 1500 | ret = kiocb_cancel(ctx, kiocb); |
906b973c KO |
1501 | else |
1502 | ret = -EINVAL; | |
1503 | ||
1da177e4 LT |
1504 | spin_unlock_irq(&ctx->ctx_lock); |
1505 | ||
906b973c | 1506 | if (!ret) { |
bec68faa KO |
1507 | /* |
1508 | * The result argument is no longer used - the io_event is | |
1509 | * always delivered via the ring buffer. -EINPROGRESS indicates | |
1510 | * cancellation is progress: | |
906b973c | 1511 | */ |
bec68faa | 1512 | ret = -EINPROGRESS; |
906b973c | 1513 | } |
1da177e4 | 1514 | |
723be6e3 | 1515 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1516 | |
1517 | return ret; | |
1518 | } | |
1519 | ||
1520 | /* io_getevents: | |
1521 | * Attempts to read at least min_nr events and up to nr events from | |
642b5123 ST |
1522 | * the completion queue for the aio_context specified by ctx_id. If |
1523 | * it succeeds, the number of read events is returned. May fail with | |
1524 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is | |
1525 | * out of range, if timeout is out of range. May fail with -EFAULT | |
1526 | * if any of the memory specified is invalid. May return 0 or | |
1527 | * < min_nr if the timeout specified by timeout has elapsed | |
1528 | * before sufficient events are available, where timeout == NULL | |
1529 | * specifies an infinite timeout. Note that the timeout pointed to by | |
6900807c | 1530 | * timeout is relative. Will fail with -ENOSYS if not implemented. |
1da177e4 | 1531 | */ |
002c8976 HC |
1532 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1533 | long, min_nr, | |
1534 | long, nr, | |
1535 | struct io_event __user *, events, | |
1536 | struct timespec __user *, timeout) | |
1da177e4 LT |
1537 | { |
1538 | struct kioctx *ioctx = lookup_ioctx(ctx_id); | |
1539 | long ret = -EINVAL; | |
1540 | ||
1541 | if (likely(ioctx)) { | |
2e410255 | 1542 | if (likely(min_nr <= nr && min_nr >= 0)) |
1da177e4 | 1543 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
723be6e3 | 1544 | percpu_ref_put(&ioctx->users); |
1da177e4 | 1545 | } |
1da177e4 LT |
1546 | return ret; |
1547 | } |