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/migrate.h> |
40 | #include <linux/ramfs.h> | |
723be6e3 | 41 | #include <linux/percpu-refcount.h> |
71ad7490 | 42 | #include <linux/mount.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 | |
e34ecee2 KO |
83 | struct percpu_ref reqs; |
84 | ||
4e179bca | 85 | unsigned long user_id; |
4e179bca | 86 | |
e1bdd5f2 KO |
87 | struct __percpu kioctx_cpu *cpu; |
88 | ||
89 | /* | |
90 | * For percpu reqs_available, number of slots we move to/from global | |
91 | * counter at a time: | |
92 | */ | |
93 | unsigned req_batch; | |
3e845ce0 KO |
94 | /* |
95 | * This is what userspace passed to io_setup(), it's not used for | |
96 | * anything but counting against the global max_reqs quota. | |
97 | * | |
58c85dc2 | 98 | * The real limit is nr_events - 1, which will be larger (see |
3e845ce0 KO |
99 | * aio_setup_ring()) |
100 | */ | |
4e179bca KO |
101 | unsigned max_reqs; |
102 | ||
58c85dc2 KO |
103 | /* Size of ringbuffer, in units of struct io_event */ |
104 | unsigned nr_events; | |
4e179bca | 105 | |
58c85dc2 KO |
106 | unsigned long mmap_base; |
107 | unsigned long mmap_size; | |
108 | ||
109 | struct page **ring_pages; | |
110 | long nr_pages; | |
111 | ||
723be6e3 | 112 | struct work_struct free_work; |
4e23bcae KO |
113 | |
114 | struct { | |
34e83fc6 KO |
115 | /* |
116 | * This counts the number of available slots in the ringbuffer, | |
117 | * so we avoid overflowing it: it's decremented (if positive) | |
118 | * when allocating a kiocb and incremented when the resulting | |
119 | * io_event is pulled off the ringbuffer. | |
e1bdd5f2 KO |
120 | * |
121 | * We batch accesses to it with a percpu version. | |
34e83fc6 KO |
122 | */ |
123 | atomic_t reqs_available; | |
4e23bcae KO |
124 | } ____cacheline_aligned_in_smp; |
125 | ||
126 | struct { | |
127 | spinlock_t ctx_lock; | |
128 | struct list_head active_reqs; /* used for cancellation */ | |
129 | } ____cacheline_aligned_in_smp; | |
130 | ||
58c85dc2 KO |
131 | struct { |
132 | struct mutex ring_lock; | |
4e23bcae KO |
133 | wait_queue_head_t wait; |
134 | } ____cacheline_aligned_in_smp; | |
58c85dc2 KO |
135 | |
136 | struct { | |
137 | unsigned tail; | |
138 | spinlock_t completion_lock; | |
4e23bcae | 139 | } ____cacheline_aligned_in_smp; |
58c85dc2 KO |
140 | |
141 | struct page *internal_pages[AIO_RING_PAGES]; | |
36bc08cc | 142 | struct file *aio_ring_file; |
db446a08 BL |
143 | |
144 | unsigned id; | |
4e179bca KO |
145 | }; |
146 | ||
1da177e4 | 147 | /*------ sysctl variables----*/ |
d55b5fda ZB |
148 | static DEFINE_SPINLOCK(aio_nr_lock); |
149 | unsigned long aio_nr; /* current system wide number of aio requests */ | |
150 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ | |
1da177e4 LT |
151 | /*----end sysctl variables---*/ |
152 | ||
e18b890b CL |
153 | static struct kmem_cache *kiocb_cachep; |
154 | static struct kmem_cache *kioctx_cachep; | |
1da177e4 | 155 | |
71ad7490 BL |
156 | static struct vfsmount *aio_mnt; |
157 | ||
158 | static const struct file_operations aio_ring_fops; | |
159 | static const struct address_space_operations aio_ctx_aops; | |
160 | ||
161 | static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) | |
162 | { | |
163 | struct qstr this = QSTR_INIT("[aio]", 5); | |
164 | struct file *file; | |
165 | struct path path; | |
166 | struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); | |
7f62656b DC |
167 | if (IS_ERR(inode)) |
168 | return ERR_CAST(inode); | |
71ad7490 BL |
169 | |
170 | inode->i_mapping->a_ops = &aio_ctx_aops; | |
171 | inode->i_mapping->private_data = ctx; | |
172 | inode->i_size = PAGE_SIZE * nr_pages; | |
173 | ||
174 | path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this); | |
175 | if (!path.dentry) { | |
176 | iput(inode); | |
177 | return ERR_PTR(-ENOMEM); | |
178 | } | |
179 | path.mnt = mntget(aio_mnt); | |
180 | ||
181 | d_instantiate(path.dentry, inode); | |
182 | file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops); | |
183 | if (IS_ERR(file)) { | |
184 | path_put(&path); | |
185 | return file; | |
186 | } | |
187 | ||
188 | file->f_flags = O_RDWR; | |
189 | file->private_data = ctx; | |
190 | return file; | |
191 | } | |
192 | ||
193 | static struct dentry *aio_mount(struct file_system_type *fs_type, | |
194 | int flags, const char *dev_name, void *data) | |
195 | { | |
196 | static const struct dentry_operations ops = { | |
197 | .d_dname = simple_dname, | |
198 | }; | |
199 | return mount_pseudo(fs_type, "aio:", NULL, &ops, 0xa10a10a1); | |
200 | } | |
201 | ||
1da177e4 LT |
202 | /* aio_setup |
203 | * Creates the slab caches used by the aio routines, panic on | |
204 | * failure as this is done early during the boot sequence. | |
205 | */ | |
206 | static int __init aio_setup(void) | |
207 | { | |
71ad7490 BL |
208 | static struct file_system_type aio_fs = { |
209 | .name = "aio", | |
210 | .mount = aio_mount, | |
211 | .kill_sb = kill_anon_super, | |
212 | }; | |
213 | aio_mnt = kern_mount(&aio_fs); | |
214 | if (IS_ERR(aio_mnt)) | |
215 | panic("Failed to create aio fs mount."); | |
216 | ||
0a31bd5f CL |
217 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
218 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); | |
1da177e4 | 219 | |
caf4167a | 220 | pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page)); |
1da177e4 LT |
221 | |
222 | return 0; | |
223 | } | |
385773e0 | 224 | __initcall(aio_setup); |
1da177e4 | 225 | |
5e9ae2e5 BL |
226 | static void put_aio_ring_file(struct kioctx *ctx) |
227 | { | |
228 | struct file *aio_ring_file = ctx->aio_ring_file; | |
229 | if (aio_ring_file) { | |
230 | truncate_setsize(aio_ring_file->f_inode, 0); | |
231 | ||
232 | /* Prevent further access to the kioctx from migratepages */ | |
233 | spin_lock(&aio_ring_file->f_inode->i_mapping->private_lock); | |
234 | aio_ring_file->f_inode->i_mapping->private_data = NULL; | |
235 | ctx->aio_ring_file = NULL; | |
236 | spin_unlock(&aio_ring_file->f_inode->i_mapping->private_lock); | |
237 | ||
238 | fput(aio_ring_file); | |
239 | } | |
240 | } | |
241 | ||
1da177e4 LT |
242 | static void aio_free_ring(struct kioctx *ctx) |
243 | { | |
36bc08cc | 244 | int i; |
1da177e4 | 245 | |
36bc08cc | 246 | for (i = 0; i < ctx->nr_pages; i++) { |
8e321fef | 247 | struct page *page; |
36bc08cc GZ |
248 | pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, |
249 | page_count(ctx->ring_pages[i])); | |
8e321fef BL |
250 | page = ctx->ring_pages[i]; |
251 | if (!page) | |
252 | continue; | |
253 | ctx->ring_pages[i] = NULL; | |
254 | put_page(page); | |
36bc08cc | 255 | } |
1da177e4 | 256 | |
5e9ae2e5 BL |
257 | put_aio_ring_file(ctx); |
258 | ||
ddb8c45b | 259 | if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) { |
58c85dc2 | 260 | kfree(ctx->ring_pages); |
ddb8c45b SL |
261 | ctx->ring_pages = NULL; |
262 | } | |
36bc08cc GZ |
263 | } |
264 | ||
265 | static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) | |
266 | { | |
267 | vma->vm_ops = &generic_file_vm_ops; | |
268 | return 0; | |
269 | } | |
270 | ||
271 | static const struct file_operations aio_ring_fops = { | |
272 | .mmap = aio_ring_mmap, | |
273 | }; | |
274 | ||
275 | static int aio_set_page_dirty(struct page *page) | |
276 | { | |
277 | return 0; | |
278 | } | |
279 | ||
0c45355f | 280 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc GZ |
281 | static int aio_migratepage(struct address_space *mapping, struct page *new, |
282 | struct page *old, enum migrate_mode mode) | |
283 | { | |
5e9ae2e5 | 284 | struct kioctx *ctx; |
36bc08cc | 285 | unsigned long flags; |
36bc08cc GZ |
286 | int rc; |
287 | ||
8e321fef BL |
288 | rc = 0; |
289 | ||
290 | /* Make sure the old page hasn't already been changed */ | |
291 | spin_lock(&mapping->private_lock); | |
292 | ctx = mapping->private_data; | |
293 | if (ctx) { | |
294 | pgoff_t idx; | |
295 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
296 | idx = old->index; | |
297 | if (idx < (pgoff_t)ctx->nr_pages) { | |
298 | if (ctx->ring_pages[idx] != old) | |
299 | rc = -EAGAIN; | |
300 | } else | |
301 | rc = -EINVAL; | |
302 | spin_unlock_irqrestore(&ctx->completion_lock, flags); | |
303 | } else | |
304 | rc = -EINVAL; | |
305 | spin_unlock(&mapping->private_lock); | |
306 | ||
307 | if (rc != 0) | |
308 | return rc; | |
309 | ||
36bc08cc GZ |
310 | /* Writeback must be complete */ |
311 | BUG_ON(PageWriteback(old)); | |
8e321fef | 312 | get_page(new); |
36bc08cc | 313 | |
8e321fef | 314 | rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1); |
36bc08cc | 315 | if (rc != MIGRATEPAGE_SUCCESS) { |
8e321fef | 316 | put_page(new); |
36bc08cc GZ |
317 | return rc; |
318 | } | |
319 | ||
5e9ae2e5 BL |
320 | /* We can potentially race against kioctx teardown here. Use the |
321 | * address_space's private data lock to protect the mapping's | |
322 | * private_data. | |
323 | */ | |
324 | spin_lock(&mapping->private_lock); | |
325 | ctx = mapping->private_data; | |
326 | if (ctx) { | |
327 | pgoff_t idx; | |
328 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
329 | migrate_page_copy(new, old); | |
330 | idx = old->index; | |
8e321fef BL |
331 | if (idx < (pgoff_t)ctx->nr_pages) { |
332 | /* And only do the move if things haven't changed */ | |
333 | if (ctx->ring_pages[idx] == old) | |
334 | ctx->ring_pages[idx] = new; | |
335 | else | |
336 | rc = -EAGAIN; | |
337 | } else | |
338 | rc = -EINVAL; | |
5e9ae2e5 BL |
339 | spin_unlock_irqrestore(&ctx->completion_lock, flags); |
340 | } else | |
341 | rc = -EBUSY; | |
342 | spin_unlock(&mapping->private_lock); | |
36bc08cc | 343 | |
8e321fef BL |
344 | if (rc == MIGRATEPAGE_SUCCESS) |
345 | put_page(old); | |
346 | else | |
347 | put_page(new); | |
348 | ||
36bc08cc | 349 | return rc; |
1da177e4 | 350 | } |
0c45355f | 351 | #endif |
1da177e4 | 352 | |
36bc08cc GZ |
353 | static const struct address_space_operations aio_ctx_aops = { |
354 | .set_page_dirty = aio_set_page_dirty, | |
0c45355f | 355 | #if IS_ENABLED(CONFIG_MIGRATION) |
36bc08cc | 356 | .migratepage = aio_migratepage, |
0c45355f | 357 | #endif |
36bc08cc GZ |
358 | }; |
359 | ||
1da177e4 LT |
360 | static int aio_setup_ring(struct kioctx *ctx) |
361 | { | |
362 | struct aio_ring *ring; | |
1da177e4 | 363 | unsigned nr_events = ctx->max_reqs; |
41003a7b | 364 | struct mm_struct *mm = current->mm; |
3dc9acb6 | 365 | unsigned long size, unused; |
1da177e4 | 366 | int nr_pages; |
36bc08cc GZ |
367 | int i; |
368 | struct file *file; | |
1da177e4 LT |
369 | |
370 | /* Compensate for the ring buffer's head/tail overlap entry */ | |
371 | nr_events += 2; /* 1 is required, 2 for good luck */ | |
372 | ||
373 | size = sizeof(struct aio_ring); | |
374 | size += sizeof(struct io_event) * nr_events; | |
1da177e4 | 375 | |
36bc08cc | 376 | nr_pages = PFN_UP(size); |
1da177e4 LT |
377 | if (nr_pages < 0) |
378 | return -EINVAL; | |
379 | ||
71ad7490 | 380 | file = aio_private_file(ctx, nr_pages); |
36bc08cc GZ |
381 | if (IS_ERR(file)) { |
382 | ctx->aio_ring_file = NULL; | |
383 | return -EAGAIN; | |
384 | } | |
385 | ||
3dc9acb6 LT |
386 | ctx->aio_ring_file = file; |
387 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) | |
388 | / sizeof(struct io_event); | |
389 | ||
390 | ctx->ring_pages = ctx->internal_pages; | |
391 | if (nr_pages > AIO_RING_PAGES) { | |
392 | ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), | |
393 | GFP_KERNEL); | |
394 | if (!ctx->ring_pages) { | |
395 | put_aio_ring_file(ctx); | |
396 | return -ENOMEM; | |
397 | } | |
398 | } | |
399 | ||
36bc08cc GZ |
400 | for (i = 0; i < nr_pages; i++) { |
401 | struct page *page; | |
402 | page = find_or_create_page(file->f_inode->i_mapping, | |
403 | i, GFP_HIGHUSER | __GFP_ZERO); | |
404 | if (!page) | |
405 | break; | |
406 | pr_debug("pid(%d) page[%d]->count=%d\n", | |
407 | current->pid, i, page_count(page)); | |
408 | SetPageUptodate(page); | |
409 | SetPageDirty(page); | |
410 | unlock_page(page); | |
3dc9acb6 LT |
411 | |
412 | ctx->ring_pages[i] = page; | |
36bc08cc | 413 | } |
3dc9acb6 | 414 | ctx->nr_pages = i; |
1da177e4 | 415 | |
3dc9acb6 LT |
416 | if (unlikely(i != nr_pages)) { |
417 | aio_free_ring(ctx); | |
418 | return -EAGAIN; | |
1da177e4 LT |
419 | } |
420 | ||
58c85dc2 KO |
421 | ctx->mmap_size = nr_pages * PAGE_SIZE; |
422 | pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); | |
36bc08cc | 423 | |
41003a7b | 424 | down_write(&mm->mmap_sem); |
36bc08cc GZ |
425 | ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, |
426 | PROT_READ | PROT_WRITE, | |
3dc9acb6 LT |
427 | MAP_SHARED, 0, &unused); |
428 | up_write(&mm->mmap_sem); | |
58c85dc2 | 429 | if (IS_ERR((void *)ctx->mmap_base)) { |
58c85dc2 | 430 | ctx->mmap_size = 0; |
1da177e4 LT |
431 | aio_free_ring(ctx); |
432 | return -EAGAIN; | |
433 | } | |
434 | ||
58c85dc2 | 435 | pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); |
d6c355c7 | 436 | |
58c85dc2 KO |
437 | ctx->user_id = ctx->mmap_base; |
438 | ctx->nr_events = nr_events; /* trusted copy */ | |
1da177e4 | 439 | |
58c85dc2 | 440 | ring = kmap_atomic(ctx->ring_pages[0]); |
1da177e4 | 441 | ring->nr = nr_events; /* user copy */ |
db446a08 | 442 | ring->id = ~0U; |
1da177e4 LT |
443 | ring->head = ring->tail = 0; |
444 | ring->magic = AIO_RING_MAGIC; | |
445 | ring->compat_features = AIO_RING_COMPAT_FEATURES; | |
446 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; | |
447 | ring->header_length = sizeof(struct aio_ring); | |
e8e3c3d6 | 448 | kunmap_atomic(ring); |
58c85dc2 | 449 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 LT |
450 | |
451 | return 0; | |
452 | } | |
453 | ||
1da177e4 LT |
454 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
455 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) | |
456 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) | |
457 | ||
0460fef2 KO |
458 | void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel) |
459 | { | |
460 | struct kioctx *ctx = req->ki_ctx; | |
461 | unsigned long flags; | |
462 | ||
463 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
464 | ||
465 | if (!req->ki_list.next) | |
466 | list_add(&req->ki_list, &ctx->active_reqs); | |
467 | ||
468 | req->ki_cancel = cancel; | |
469 | ||
470 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
471 | } | |
472 | EXPORT_SYMBOL(kiocb_set_cancel_fn); | |
473 | ||
bec68faa | 474 | static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb) |
906b973c | 475 | { |
0460fef2 | 476 | kiocb_cancel_fn *old, *cancel; |
906b973c | 477 | |
0460fef2 KO |
478 | /* |
479 | * Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it | |
480 | * actually has a cancel function, hence the cmpxchg() | |
481 | */ | |
482 | ||
483 | cancel = ACCESS_ONCE(kiocb->ki_cancel); | |
484 | do { | |
485 | if (!cancel || cancel == KIOCB_CANCELLED) | |
57282d8f | 486 | return -EINVAL; |
906b973c | 487 | |
0460fef2 KO |
488 | old = cancel; |
489 | cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED); | |
490 | } while (cancel != old); | |
906b973c | 491 | |
57282d8f | 492 | return cancel(kiocb); |
906b973c KO |
493 | } |
494 | ||
e34ecee2 | 495 | static void free_ioctx(struct work_struct *work) |
36f55889 | 496 | { |
e34ecee2 | 497 | struct kioctx *ctx = container_of(work, struct kioctx, free_work); |
e1bdd5f2 | 498 | |
e34ecee2 | 499 | pr_debug("freeing %p\n", ctx); |
e1bdd5f2 | 500 | |
e34ecee2 | 501 | aio_free_ring(ctx); |
e1bdd5f2 | 502 | free_percpu(ctx->cpu); |
36f55889 KO |
503 | kmem_cache_free(kioctx_cachep, ctx); |
504 | } | |
505 | ||
e34ecee2 KO |
506 | static void free_ioctx_reqs(struct percpu_ref *ref) |
507 | { | |
508 | struct kioctx *ctx = container_of(ref, struct kioctx, reqs); | |
509 | ||
510 | INIT_WORK(&ctx->free_work, free_ioctx); | |
511 | schedule_work(&ctx->free_work); | |
512 | } | |
513 | ||
36f55889 KO |
514 | /* |
515 | * When this function runs, the kioctx has been removed from the "hash table" | |
516 | * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - | |
517 | * now it's safe to cancel any that need to be. | |
518 | */ | |
e34ecee2 | 519 | static void free_ioctx_users(struct percpu_ref *ref) |
36f55889 | 520 | { |
e34ecee2 | 521 | struct kioctx *ctx = container_of(ref, struct kioctx, users); |
36f55889 KO |
522 | struct kiocb *req; |
523 | ||
524 | spin_lock_irq(&ctx->ctx_lock); | |
525 | ||
526 | while (!list_empty(&ctx->active_reqs)) { | |
527 | req = list_first_entry(&ctx->active_reqs, | |
528 | struct kiocb, ki_list); | |
529 | ||
530 | list_del_init(&req->ki_list); | |
bec68faa | 531 | kiocb_cancel(ctx, req); |
36f55889 KO |
532 | } |
533 | ||
534 | spin_unlock_irq(&ctx->ctx_lock); | |
535 | ||
e34ecee2 KO |
536 | percpu_ref_kill(&ctx->reqs); |
537 | percpu_ref_put(&ctx->reqs); | |
36f55889 KO |
538 | } |
539 | ||
db446a08 BL |
540 | static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) |
541 | { | |
542 | unsigned i, new_nr; | |
543 | struct kioctx_table *table, *old; | |
544 | struct aio_ring *ring; | |
545 | ||
546 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 547 | rcu_read_lock(); |
77d30b14 | 548 | table = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
549 | |
550 | while (1) { | |
551 | if (table) | |
552 | for (i = 0; i < table->nr; i++) | |
553 | if (!table->table[i]) { | |
554 | ctx->id = i; | |
555 | table->table[i] = ctx; | |
d9b2c871 | 556 | rcu_read_unlock(); |
db446a08 BL |
557 | spin_unlock(&mm->ioctx_lock); |
558 | ||
559 | ring = kmap_atomic(ctx->ring_pages[0]); | |
560 | ring->id = ctx->id; | |
561 | kunmap_atomic(ring); | |
562 | return 0; | |
563 | } | |
564 | ||
565 | new_nr = (table ? table->nr : 1) * 4; | |
566 | ||
d9b2c871 | 567 | rcu_read_unlock(); |
db446a08 BL |
568 | spin_unlock(&mm->ioctx_lock); |
569 | ||
570 | table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * | |
571 | new_nr, GFP_KERNEL); | |
572 | if (!table) | |
573 | return -ENOMEM; | |
574 | ||
575 | table->nr = new_nr; | |
576 | ||
577 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 578 | rcu_read_lock(); |
77d30b14 | 579 | old = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
580 | |
581 | if (!old) { | |
582 | rcu_assign_pointer(mm->ioctx_table, table); | |
583 | } else if (table->nr > old->nr) { | |
584 | memcpy(table->table, old->table, | |
585 | old->nr * sizeof(struct kioctx *)); | |
586 | ||
587 | rcu_assign_pointer(mm->ioctx_table, table); | |
588 | kfree_rcu(old, rcu); | |
589 | } else { | |
590 | kfree(table); | |
591 | table = old; | |
592 | } | |
593 | } | |
594 | } | |
595 | ||
e34ecee2 KO |
596 | static void aio_nr_sub(unsigned nr) |
597 | { | |
598 | spin_lock(&aio_nr_lock); | |
599 | if (WARN_ON(aio_nr - nr > aio_nr)) | |
600 | aio_nr = 0; | |
601 | else | |
602 | aio_nr -= nr; | |
603 | spin_unlock(&aio_nr_lock); | |
604 | } | |
605 | ||
1da177e4 LT |
606 | /* ioctx_alloc |
607 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. | |
608 | */ | |
609 | static struct kioctx *ioctx_alloc(unsigned nr_events) | |
610 | { | |
41003a7b | 611 | struct mm_struct *mm = current->mm; |
1da177e4 | 612 | struct kioctx *ctx; |
e23754f8 | 613 | int err = -ENOMEM; |
1da177e4 | 614 | |
e1bdd5f2 KO |
615 | /* |
616 | * We keep track of the number of available ringbuffer slots, to prevent | |
617 | * overflow (reqs_available), and we also use percpu counters for this. | |
618 | * | |
619 | * So since up to half the slots might be on other cpu's percpu counters | |
620 | * and unavailable, double nr_events so userspace sees what they | |
621 | * expected: additionally, we move req_batch slots to/from percpu | |
622 | * counters at a time, so make sure that isn't 0: | |
623 | */ | |
624 | nr_events = max(nr_events, num_possible_cpus() * 4); | |
625 | nr_events *= 2; | |
626 | ||
1da177e4 LT |
627 | /* Prevent overflows */ |
628 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || | |
629 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { | |
630 | pr_debug("ENOMEM: nr_events too high\n"); | |
631 | return ERR_PTR(-EINVAL); | |
632 | } | |
633 | ||
4cd81c3d | 634 | if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL)) |
1da177e4 LT |
635 | return ERR_PTR(-EAGAIN); |
636 | ||
c3762229 | 637 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
1da177e4 LT |
638 | if (!ctx) |
639 | return ERR_PTR(-ENOMEM); | |
640 | ||
1da177e4 | 641 | ctx->max_reqs = nr_events; |
1da177e4 | 642 | |
e34ecee2 KO |
643 | if (percpu_ref_init(&ctx->users, free_ioctx_users)) |
644 | goto err; | |
645 | ||
646 | if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs)) | |
647 | goto err; | |
723be6e3 | 648 | |
1da177e4 | 649 | spin_lock_init(&ctx->ctx_lock); |
0460fef2 | 650 | spin_lock_init(&ctx->completion_lock); |
58c85dc2 | 651 | mutex_init(&ctx->ring_lock); |
1da177e4 LT |
652 | init_waitqueue_head(&ctx->wait); |
653 | ||
654 | INIT_LIST_HEAD(&ctx->active_reqs); | |
1da177e4 | 655 | |
e1bdd5f2 KO |
656 | ctx->cpu = alloc_percpu(struct kioctx_cpu); |
657 | if (!ctx->cpu) | |
e34ecee2 | 658 | goto err; |
1da177e4 | 659 | |
e1bdd5f2 | 660 | if (aio_setup_ring(ctx) < 0) |
e34ecee2 | 661 | goto err; |
e1bdd5f2 | 662 | |
34e83fc6 | 663 | atomic_set(&ctx->reqs_available, ctx->nr_events - 1); |
e1bdd5f2 | 664 | ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); |
6878ea72 BL |
665 | if (ctx->req_batch < 1) |
666 | ctx->req_batch = 1; | |
34e83fc6 | 667 | |
1da177e4 | 668 | /* limit the number of system wide aios */ |
9fa1cb39 | 669 | spin_lock(&aio_nr_lock); |
4cd81c3d | 670 | if (aio_nr + nr_events > (aio_max_nr * 2UL) || |
2dd542b7 | 671 | aio_nr + nr_events < aio_nr) { |
9fa1cb39 | 672 | spin_unlock(&aio_nr_lock); |
e34ecee2 | 673 | err = -EAGAIN; |
d1b94327 | 674 | goto err_ctx; |
2dd542b7 AV |
675 | } |
676 | aio_nr += ctx->max_reqs; | |
9fa1cb39 | 677 | spin_unlock(&aio_nr_lock); |
1da177e4 | 678 | |
1881686f BL |
679 | percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ |
680 | percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */ | |
723be6e3 | 681 | |
da90382c BL |
682 | err = ioctx_add_table(ctx, mm); |
683 | if (err) | |
e34ecee2 | 684 | goto err_cleanup; |
da90382c | 685 | |
caf4167a | 686 | pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
58c85dc2 | 687 | ctx, ctx->user_id, mm, ctx->nr_events); |
1da177e4 LT |
688 | return ctx; |
689 | ||
e34ecee2 KO |
690 | err_cleanup: |
691 | aio_nr_sub(ctx->max_reqs); | |
d1b94327 GZ |
692 | err_ctx: |
693 | aio_free_ring(ctx); | |
e34ecee2 | 694 | err: |
e1bdd5f2 | 695 | free_percpu(ctx->cpu); |
e34ecee2 | 696 | free_percpu(ctx->reqs.pcpu_count); |
723be6e3 | 697 | free_percpu(ctx->users.pcpu_count); |
1da177e4 | 698 | kmem_cache_free(kioctx_cachep, ctx); |
caf4167a | 699 | pr_debug("error allocating ioctx %d\n", err); |
e23754f8 | 700 | return ERR_PTR(err); |
1da177e4 LT |
701 | } |
702 | ||
36f55889 KO |
703 | /* kill_ioctx |
704 | * Cancels all outstanding aio requests on an aio context. Used | |
705 | * when the processes owning a context have all exited to encourage | |
706 | * the rapid destruction of the kioctx. | |
707 | */ | |
db446a08 | 708 | static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx) |
36f55889 KO |
709 | { |
710 | if (!atomic_xchg(&ctx->dead, 1)) { | |
db446a08 BL |
711 | struct kioctx_table *table; |
712 | ||
713 | spin_lock(&mm->ioctx_lock); | |
d9b2c871 | 714 | rcu_read_lock(); |
77d30b14 | 715 | table = rcu_dereference(mm->ioctx_table); |
db446a08 BL |
716 | |
717 | WARN_ON(ctx != table->table[ctx->id]); | |
718 | table->table[ctx->id] = NULL; | |
d9b2c871 | 719 | rcu_read_unlock(); |
db446a08 BL |
720 | spin_unlock(&mm->ioctx_lock); |
721 | ||
723be6e3 KO |
722 | /* percpu_ref_kill() will do the necessary call_rcu() */ |
723 | wake_up_all(&ctx->wait); | |
dee11c23 | 724 | |
36f55889 | 725 | /* |
4fcc712f KO |
726 | * It'd be more correct to do this in free_ioctx(), after all |
727 | * the outstanding kiocbs have finished - but by then io_destroy | |
728 | * has already returned, so io_setup() could potentially return | |
729 | * -EAGAIN with no ioctxs actually in use (as far as userspace | |
730 | * could tell). | |
36f55889 | 731 | */ |
e34ecee2 | 732 | aio_nr_sub(ctx->max_reqs); |
4fcc712f KO |
733 | |
734 | if (ctx->mmap_size) | |
735 | vm_munmap(ctx->mmap_base, ctx->mmap_size); | |
736 | ||
723be6e3 | 737 | percpu_ref_kill(&ctx->users); |
36f55889 | 738 | } |
1da177e4 LT |
739 | } |
740 | ||
741 | /* wait_on_sync_kiocb: | |
742 | * Waits on the given sync kiocb to complete. | |
743 | */ | |
57282d8f | 744 | ssize_t wait_on_sync_kiocb(struct kiocb *req) |
1da177e4 | 745 | { |
57282d8f | 746 | while (!req->ki_ctx) { |
1da177e4 | 747 | set_current_state(TASK_UNINTERRUPTIBLE); |
57282d8f | 748 | if (req->ki_ctx) |
1da177e4 | 749 | break; |
41d10da3 | 750 | io_schedule(); |
1da177e4 LT |
751 | } |
752 | __set_current_state(TASK_RUNNING); | |
57282d8f | 753 | return req->ki_user_data; |
1da177e4 | 754 | } |
385773e0 | 755 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
1da177e4 | 756 | |
36f55889 KO |
757 | /* |
758 | * exit_aio: called when the last user of mm goes away. At this point, there is | |
759 | * no way for any new requests to be submited or any of the io_* syscalls to be | |
760 | * called on the context. | |
761 | * | |
762 | * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on | |
763 | * them. | |
1da177e4 | 764 | */ |
fc9b52cd | 765 | void exit_aio(struct mm_struct *mm) |
1da177e4 | 766 | { |
db446a08 | 767 | struct kioctx_table *table; |
abf137dd | 768 | struct kioctx *ctx; |
db446a08 BL |
769 | unsigned i = 0; |
770 | ||
771 | while (1) { | |
772 | rcu_read_lock(); | |
773 | table = rcu_dereference(mm->ioctx_table); | |
774 | ||
775 | do { | |
776 | if (!table || i >= table->nr) { | |
777 | rcu_read_unlock(); | |
778 | rcu_assign_pointer(mm->ioctx_table, NULL); | |
779 | if (table) | |
780 | kfree(table); | |
781 | return; | |
782 | } | |
783 | ||
784 | ctx = table->table[i++]; | |
785 | } while (!ctx); | |
786 | ||
787 | rcu_read_unlock(); | |
abf137dd | 788 | |
936af157 AV |
789 | /* |
790 | * We don't need to bother with munmap() here - | |
791 | * exit_mmap(mm) is coming and it'll unmap everything. | |
792 | * Since aio_free_ring() uses non-zero ->mmap_size | |
793 | * as indicator that it needs to unmap the area, | |
794 | * just set it to 0; aio_free_ring() is the only | |
795 | * place that uses ->mmap_size, so it's safe. | |
936af157 | 796 | */ |
58c85dc2 | 797 | ctx->mmap_size = 0; |
36f55889 | 798 | |
db446a08 | 799 | kill_ioctx(mm, ctx); |
1da177e4 LT |
800 | } |
801 | } | |
802 | ||
e1bdd5f2 KO |
803 | static void put_reqs_available(struct kioctx *ctx, unsigned nr) |
804 | { | |
805 | struct kioctx_cpu *kcpu; | |
806 | ||
807 | preempt_disable(); | |
808 | kcpu = this_cpu_ptr(ctx->cpu); | |
809 | ||
810 | kcpu->reqs_available += nr; | |
811 | while (kcpu->reqs_available >= ctx->req_batch * 2) { | |
812 | kcpu->reqs_available -= ctx->req_batch; | |
813 | atomic_add(ctx->req_batch, &ctx->reqs_available); | |
814 | } | |
815 | ||
816 | preempt_enable(); | |
817 | } | |
818 | ||
819 | static bool get_reqs_available(struct kioctx *ctx) | |
820 | { | |
821 | struct kioctx_cpu *kcpu; | |
822 | bool ret = false; | |
823 | ||
824 | preempt_disable(); | |
825 | kcpu = this_cpu_ptr(ctx->cpu); | |
826 | ||
827 | if (!kcpu->reqs_available) { | |
828 | int old, avail = atomic_read(&ctx->reqs_available); | |
829 | ||
830 | do { | |
831 | if (avail < ctx->req_batch) | |
832 | goto out; | |
833 | ||
834 | old = avail; | |
835 | avail = atomic_cmpxchg(&ctx->reqs_available, | |
836 | avail, avail - ctx->req_batch); | |
837 | } while (avail != old); | |
838 | ||
839 | kcpu->reqs_available += ctx->req_batch; | |
840 | } | |
841 | ||
842 | ret = true; | |
843 | kcpu->reqs_available--; | |
844 | out: | |
845 | preempt_enable(); | |
846 | return ret; | |
847 | } | |
848 | ||
1da177e4 | 849 | /* aio_get_req |
57282d8f KO |
850 | * Allocate a slot for an aio request. |
851 | * Returns NULL if no requests are free. | |
1da177e4 | 852 | */ |
a1c8eae7 | 853 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
1da177e4 | 854 | { |
a1c8eae7 KO |
855 | struct kiocb *req; |
856 | ||
e1bdd5f2 | 857 | if (!get_reqs_available(ctx)) |
a1c8eae7 KO |
858 | return NULL; |
859 | ||
0460fef2 | 860 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); |
1da177e4 | 861 | if (unlikely(!req)) |
a1c8eae7 | 862 | goto out_put; |
1da177e4 | 863 | |
e34ecee2 KO |
864 | percpu_ref_get(&ctx->reqs); |
865 | ||
1da177e4 | 866 | req->ki_ctx = ctx; |
080d676d | 867 | return req; |
a1c8eae7 | 868 | out_put: |
e1bdd5f2 | 869 | put_reqs_available(ctx, 1); |
a1c8eae7 | 870 | return NULL; |
1da177e4 LT |
871 | } |
872 | ||
11599eba | 873 | static void kiocb_free(struct kiocb *req) |
1da177e4 | 874 | { |
1d98ebfc KO |
875 | if (req->ki_filp) |
876 | fput(req->ki_filp); | |
13389010 DL |
877 | if (req->ki_eventfd != NULL) |
878 | eventfd_ctx_put(req->ki_eventfd); | |
1da177e4 | 879 | kmem_cache_free(kiocb_cachep, req); |
1da177e4 LT |
880 | } |
881 | ||
d5470b59 | 882 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
1da177e4 | 883 | { |
db446a08 | 884 | struct aio_ring __user *ring = (void __user *)ctx_id; |
abf137dd | 885 | struct mm_struct *mm = current->mm; |
65c24491 | 886 | struct kioctx *ctx, *ret = NULL; |
db446a08 BL |
887 | struct kioctx_table *table; |
888 | unsigned id; | |
889 | ||
890 | if (get_user(id, &ring->id)) | |
891 | return NULL; | |
1da177e4 | 892 | |
abf137dd | 893 | rcu_read_lock(); |
db446a08 | 894 | table = rcu_dereference(mm->ioctx_table); |
abf137dd | 895 | |
db446a08 BL |
896 | if (!table || id >= table->nr) |
897 | goto out; | |
1da177e4 | 898 | |
db446a08 | 899 | ctx = table->table[id]; |
f30d704f | 900 | if (ctx && ctx->user_id == ctx_id) { |
db446a08 BL |
901 | percpu_ref_get(&ctx->users); |
902 | ret = ctx; | |
903 | } | |
904 | out: | |
abf137dd | 905 | rcu_read_unlock(); |
65c24491 | 906 | return ret; |
1da177e4 LT |
907 | } |
908 | ||
1da177e4 LT |
909 | /* aio_complete |
910 | * Called when the io request on the given iocb is complete. | |
1da177e4 | 911 | */ |
2d68449e | 912 | void aio_complete(struct kiocb *iocb, long res, long res2) |
1da177e4 LT |
913 | { |
914 | struct kioctx *ctx = iocb->ki_ctx; | |
1da177e4 | 915 | struct aio_ring *ring; |
21b40200 | 916 | struct io_event *ev_page, *event; |
1da177e4 | 917 | unsigned long flags; |
21b40200 | 918 | unsigned tail, pos; |
1da177e4 | 919 | |
20dcae32 ZB |
920 | /* |
921 | * Special case handling for sync iocbs: | |
922 | * - events go directly into the iocb for fast handling | |
923 | * - the sync task with the iocb in its stack holds the single iocb | |
924 | * ref, no other paths have a way to get another ref | |
925 | * - the sync task helpfully left a reference to itself in the iocb | |
1da177e4 LT |
926 | */ |
927 | if (is_sync_kiocb(iocb)) { | |
1da177e4 | 928 | iocb->ki_user_data = res; |
57282d8f KO |
929 | smp_wmb(); |
930 | iocb->ki_ctx = ERR_PTR(-EXDEV); | |
1da177e4 | 931 | wake_up_process(iocb->ki_obj.tsk); |
2d68449e | 932 | return; |
1da177e4 LT |
933 | } |
934 | ||
0460fef2 KO |
935 | if (iocb->ki_list.next) { |
936 | unsigned long flags; | |
937 | ||
938 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
939 | list_del(&iocb->ki_list); | |
940 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
941 | } | |
11599eba | 942 | |
0460fef2 KO |
943 | /* |
944 | * Add a completion event to the ring buffer. Must be done holding | |
4b30f07e | 945 | * ctx->completion_lock to prevent other code from messing with the tail |
0460fef2 KO |
946 | * pointer since we might be called from irq context. |
947 | */ | |
948 | spin_lock_irqsave(&ctx->completion_lock, flags); | |
949 | ||
58c85dc2 | 950 | tail = ctx->tail; |
21b40200 KO |
951 | pos = tail + AIO_EVENTS_OFFSET; |
952 | ||
58c85dc2 | 953 | if (++tail >= ctx->nr_events) |
4bf69b2a | 954 | tail = 0; |
1da177e4 | 955 | |
58c85dc2 | 956 | ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
957 | event = ev_page + pos % AIO_EVENTS_PER_PAGE; |
958 | ||
1da177e4 LT |
959 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
960 | event->data = iocb->ki_user_data; | |
961 | event->res = res; | |
962 | event->res2 = res2; | |
963 | ||
21b40200 | 964 | kunmap_atomic(ev_page); |
58c85dc2 | 965 | flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
21b40200 KO |
966 | |
967 | pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n", | |
caf4167a KO |
968 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
969 | res, res2); | |
1da177e4 LT |
970 | |
971 | /* after flagging the request as done, we | |
972 | * must never even look at it again | |
973 | */ | |
974 | smp_wmb(); /* make event visible before updating tail */ | |
975 | ||
58c85dc2 | 976 | ctx->tail = tail; |
1da177e4 | 977 | |
58c85dc2 | 978 | ring = kmap_atomic(ctx->ring_pages[0]); |
21b40200 | 979 | ring->tail = tail; |
e8e3c3d6 | 980 | kunmap_atomic(ring); |
58c85dc2 | 981 | flush_dcache_page(ctx->ring_pages[0]); |
1da177e4 | 982 | |
0460fef2 KO |
983 | spin_unlock_irqrestore(&ctx->completion_lock, flags); |
984 | ||
21b40200 | 985 | pr_debug("added to ring %p at [%u]\n", iocb, tail); |
8d1c98b0 DL |
986 | |
987 | /* | |
988 | * Check if the user asked us to deliver the result through an | |
989 | * eventfd. The eventfd_signal() function is safe to be called | |
990 | * from IRQ context. | |
991 | */ | |
87c3a86e | 992 | if (iocb->ki_eventfd != NULL) |
8d1c98b0 DL |
993 | eventfd_signal(iocb->ki_eventfd, 1); |
994 | ||
1da177e4 | 995 | /* everything turned out well, dispose of the aiocb. */ |
57282d8f | 996 | kiocb_free(iocb); |
1da177e4 | 997 | |
6cb2a210 QB |
998 | /* |
999 | * We have to order our ring_info tail store above and test | |
1000 | * of the wait list below outside the wait lock. This is | |
1001 | * like in wake_up_bit() where clearing a bit has to be | |
1002 | * ordered with the unlocked test. | |
1003 | */ | |
1004 | smp_mb(); | |
1005 | ||
1da177e4 LT |
1006 | if (waitqueue_active(&ctx->wait)) |
1007 | wake_up(&ctx->wait); | |
1008 | ||
e34ecee2 | 1009 | percpu_ref_put(&ctx->reqs); |
1da177e4 | 1010 | } |
385773e0 | 1011 | EXPORT_SYMBOL(aio_complete); |
1da177e4 | 1012 | |
a31ad380 KO |
1013 | /* aio_read_events |
1014 | * Pull an event off of the ioctx's event ring. Returns the number of | |
1015 | * events fetched | |
1da177e4 | 1016 | */ |
a31ad380 KO |
1017 | static long aio_read_events_ring(struct kioctx *ctx, |
1018 | struct io_event __user *event, long nr) | |
1da177e4 | 1019 | { |
1da177e4 | 1020 | struct aio_ring *ring; |
5ffac122 | 1021 | unsigned head, tail, pos; |
a31ad380 KO |
1022 | long ret = 0; |
1023 | int copy_ret; | |
1024 | ||
58c85dc2 | 1025 | mutex_lock(&ctx->ring_lock); |
1da177e4 | 1026 | |
58c85dc2 | 1027 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 1028 | head = ring->head; |
5ffac122 | 1029 | tail = ring->tail; |
a31ad380 KO |
1030 | kunmap_atomic(ring); |
1031 | ||
5ffac122 | 1032 | pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); |
1da177e4 | 1033 | |
5ffac122 | 1034 | if (head == tail) |
1da177e4 LT |
1035 | goto out; |
1036 | ||
a31ad380 KO |
1037 | while (ret < nr) { |
1038 | long avail; | |
1039 | struct io_event *ev; | |
1040 | struct page *page; | |
1041 | ||
5ffac122 KO |
1042 | avail = (head <= tail ? tail : ctx->nr_events) - head; |
1043 | if (head == tail) | |
a31ad380 KO |
1044 | break; |
1045 | ||
1046 | avail = min(avail, nr - ret); | |
1047 | avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - | |
1048 | ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE)); | |
1049 | ||
1050 | pos = head + AIO_EVENTS_OFFSET; | |
58c85dc2 | 1051 | page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; |
a31ad380 KO |
1052 | pos %= AIO_EVENTS_PER_PAGE; |
1053 | ||
1054 | ev = kmap(page); | |
1055 | copy_ret = copy_to_user(event + ret, ev + pos, | |
1056 | sizeof(*ev) * avail); | |
1057 | kunmap(page); | |
1058 | ||
1059 | if (unlikely(copy_ret)) { | |
1060 | ret = -EFAULT; | |
1061 | goto out; | |
1062 | } | |
1063 | ||
1064 | ret += avail; | |
1065 | head += avail; | |
58c85dc2 | 1066 | head %= ctx->nr_events; |
1da177e4 | 1067 | } |
1da177e4 | 1068 | |
58c85dc2 | 1069 | ring = kmap_atomic(ctx->ring_pages[0]); |
a31ad380 | 1070 | ring->head = head; |
91d80a84 | 1071 | kunmap_atomic(ring); |
58c85dc2 | 1072 | flush_dcache_page(ctx->ring_pages[0]); |
a31ad380 | 1073 | |
5ffac122 | 1074 | pr_debug("%li h%u t%u\n", ret, head, tail); |
3e845ce0 | 1075 | |
e1bdd5f2 | 1076 | put_reqs_available(ctx, ret); |
a31ad380 | 1077 | out: |
58c85dc2 | 1078 | mutex_unlock(&ctx->ring_lock); |
a31ad380 | 1079 | |
1da177e4 LT |
1080 | return ret; |
1081 | } | |
1082 | ||
a31ad380 KO |
1083 | static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, |
1084 | struct io_event __user *event, long *i) | |
1da177e4 | 1085 | { |
a31ad380 | 1086 | long ret = aio_read_events_ring(ctx, event + *i, nr - *i); |
1da177e4 | 1087 | |
a31ad380 KO |
1088 | if (ret > 0) |
1089 | *i += ret; | |
1da177e4 | 1090 | |
a31ad380 KO |
1091 | if (unlikely(atomic_read(&ctx->dead))) |
1092 | ret = -EINVAL; | |
1da177e4 | 1093 | |
a31ad380 KO |
1094 | if (!*i) |
1095 | *i = ret; | |
1da177e4 | 1096 | |
a31ad380 | 1097 | return ret < 0 || *i >= min_nr; |
1da177e4 LT |
1098 | } |
1099 | ||
a31ad380 | 1100 | static long read_events(struct kioctx *ctx, long min_nr, long nr, |
1da177e4 LT |
1101 | struct io_event __user *event, |
1102 | struct timespec __user *timeout) | |
1103 | { | |
a31ad380 KO |
1104 | ktime_t until = { .tv64 = KTIME_MAX }; |
1105 | long ret = 0; | |
1da177e4 | 1106 | |
1da177e4 LT |
1107 | if (timeout) { |
1108 | struct timespec ts; | |
a31ad380 | 1109 | |
1da177e4 | 1110 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
a31ad380 | 1111 | return -EFAULT; |
1da177e4 | 1112 | |
a31ad380 | 1113 | until = timespec_to_ktime(ts); |
1da177e4 LT |
1114 | } |
1115 | ||
a31ad380 KO |
1116 | /* |
1117 | * Note that aio_read_events() is being called as the conditional - i.e. | |
1118 | * we're calling it after prepare_to_wait() has set task state to | |
1119 | * TASK_INTERRUPTIBLE. | |
1120 | * | |
1121 | * But aio_read_events() can block, and if it blocks it's going to flip | |
1122 | * the task state back to TASK_RUNNING. | |
1123 | * | |
1124 | * This should be ok, provided it doesn't flip the state back to | |
1125 | * TASK_RUNNING and return 0 too much - that causes us to spin. That | |
1126 | * will only happen if the mutex_lock() call blocks, and we then find | |
1127 | * the ringbuffer empty. So in practice we should be ok, but it's | |
1128 | * something to be aware of when touching this code. | |
1129 | */ | |
1130 | wait_event_interruptible_hrtimeout(ctx->wait, | |
1131 | aio_read_events(ctx, min_nr, nr, event, &ret), until); | |
1da177e4 | 1132 | |
a31ad380 KO |
1133 | if (!ret && signal_pending(current)) |
1134 | ret = -EINTR; | |
1da177e4 | 1135 | |
a31ad380 | 1136 | return ret; |
1da177e4 LT |
1137 | } |
1138 | ||
1da177e4 LT |
1139 | /* sys_io_setup: |
1140 | * Create an aio_context capable of receiving at least nr_events. | |
1141 | * ctxp must not point to an aio_context that already exists, and | |
1142 | * must be initialized to 0 prior to the call. On successful | |
1143 | * creation of the aio_context, *ctxp is filled in with the resulting | |
1144 | * handle. May fail with -EINVAL if *ctxp is not initialized, | |
1145 | * if the specified nr_events exceeds internal limits. May fail | |
1146 | * with -EAGAIN if the specified nr_events exceeds the user's limit | |
1147 | * of available events. May fail with -ENOMEM if insufficient kernel | |
1148 | * resources are available. May fail with -EFAULT if an invalid | |
1149 | * pointer is passed for ctxp. Will fail with -ENOSYS if not | |
1150 | * implemented. | |
1151 | */ | |
002c8976 | 1152 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1da177e4 LT |
1153 | { |
1154 | struct kioctx *ioctx = NULL; | |
1155 | unsigned long ctx; | |
1156 | long ret; | |
1157 | ||
1158 | ret = get_user(ctx, ctxp); | |
1159 | if (unlikely(ret)) | |
1160 | goto out; | |
1161 | ||
1162 | ret = -EINVAL; | |
d55b5fda ZB |
1163 | if (unlikely(ctx || nr_events == 0)) { |
1164 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", | |
1165 | ctx, nr_events); | |
1da177e4 LT |
1166 | goto out; |
1167 | } | |
1168 | ||
1169 | ioctx = ioctx_alloc(nr_events); | |
1170 | ret = PTR_ERR(ioctx); | |
1171 | if (!IS_ERR(ioctx)) { | |
1172 | ret = put_user(ioctx->user_id, ctxp); | |
a2e1859a | 1173 | if (ret) |
db446a08 | 1174 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1175 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1176 | } |
1177 | ||
1178 | out: | |
1179 | return ret; | |
1180 | } | |
1181 | ||
1182 | /* sys_io_destroy: | |
1183 | * Destroy the aio_context specified. May cancel any outstanding | |
1184 | * AIOs and block on completion. Will fail with -ENOSYS if not | |
642b5123 | 1185 | * implemented. May fail with -EINVAL if the context pointed to |
1da177e4 LT |
1186 | * is invalid. |
1187 | */ | |
002c8976 | 1188 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1da177e4 LT |
1189 | { |
1190 | struct kioctx *ioctx = lookup_ioctx(ctx); | |
1191 | if (likely(NULL != ioctx)) { | |
db446a08 | 1192 | kill_ioctx(current->mm, ioctx); |
723be6e3 | 1193 | percpu_ref_put(&ioctx->users); |
1da177e4 LT |
1194 | return 0; |
1195 | } | |
1196 | pr_debug("EINVAL: io_destroy: invalid context id\n"); | |
1197 | return -EINVAL; | |
1198 | } | |
1199 | ||
41ef4eb8 KO |
1200 | typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *, |
1201 | unsigned long, loff_t); | |
1202 | ||
8bc92afc KO |
1203 | static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb, |
1204 | int rw, char __user *buf, | |
1205 | unsigned long *nr_segs, | |
1206 | struct iovec **iovec, | |
1207 | bool compat) | |
eed4e51f BP |
1208 | { |
1209 | ssize_t ret; | |
1210 | ||
8bc92afc | 1211 | *nr_segs = kiocb->ki_nbytes; |
41ef4eb8 | 1212 | |
9d85cba7 JM |
1213 | #ifdef CONFIG_COMPAT |
1214 | if (compat) | |
41ef4eb8 | 1215 | ret = compat_rw_copy_check_uvector(rw, |
8bc92afc KO |
1216 | (struct compat_iovec __user *)buf, |
1217 | *nr_segs, 1, *iovec, iovec); | |
9d85cba7 JM |
1218 | else |
1219 | #endif | |
41ef4eb8 | 1220 | ret = rw_copy_check_uvector(rw, |
8bc92afc KO |
1221 | (struct iovec __user *)buf, |
1222 | *nr_segs, 1, *iovec, iovec); | |
eed4e51f | 1223 | if (ret < 0) |
41ef4eb8 | 1224 | return ret; |
a70b52ec | 1225 | |
41ef4eb8 | 1226 | /* ki_nbytes now reflect bytes instead of segs */ |
eed4e51f | 1227 | kiocb->ki_nbytes = ret; |
41ef4eb8 | 1228 | return 0; |
eed4e51f BP |
1229 | } |
1230 | ||
8bc92afc KO |
1231 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb, |
1232 | int rw, char __user *buf, | |
1233 | unsigned long *nr_segs, | |
1234 | struct iovec *iovec) | |
eed4e51f | 1235 | { |
8bc92afc | 1236 | if (unlikely(!access_ok(!rw, buf, kiocb->ki_nbytes))) |
41ef4eb8 | 1237 | return -EFAULT; |
a70b52ec | 1238 | |
8bc92afc KO |
1239 | iovec->iov_base = buf; |
1240 | iovec->iov_len = kiocb->ki_nbytes; | |
1241 | *nr_segs = 1; | |
eed4e51f BP |
1242 | return 0; |
1243 | } | |
1244 | ||
1da177e4 LT |
1245 | /* |
1246 | * aio_setup_iocb: | |
1247 | * Performs the initial checks and aio retry method | |
1248 | * setup for the kiocb at the time of io submission. | |
1249 | */ | |
8bc92afc KO |
1250 | static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode, |
1251 | char __user *buf, bool compat) | |
1da177e4 | 1252 | { |
41ef4eb8 KO |
1253 | struct file *file = req->ki_filp; |
1254 | ssize_t ret; | |
8bc92afc | 1255 | unsigned long nr_segs; |
41ef4eb8 KO |
1256 | int rw; |
1257 | fmode_t mode; | |
1258 | aio_rw_op *rw_op; | |
8bc92afc | 1259 | struct iovec inline_vec, *iovec = &inline_vec; |
1da177e4 | 1260 | |
8bc92afc | 1261 | switch (opcode) { |
1da177e4 | 1262 | case IOCB_CMD_PREAD: |
eed4e51f | 1263 | case IOCB_CMD_PREADV: |
41ef4eb8 KO |
1264 | mode = FMODE_READ; |
1265 | rw = READ; | |
1266 | rw_op = file->f_op->aio_read; | |
1267 | goto rw_common; | |
1268 | ||
1269 | case IOCB_CMD_PWRITE: | |
eed4e51f | 1270 | case IOCB_CMD_PWRITEV: |
41ef4eb8 KO |
1271 | mode = FMODE_WRITE; |
1272 | rw = WRITE; | |
1273 | rw_op = file->f_op->aio_write; | |
1274 | goto rw_common; | |
1275 | rw_common: | |
1276 | if (unlikely(!(file->f_mode & mode))) | |
1277 | return -EBADF; | |
1278 | ||
1279 | if (!rw_op) | |
1280 | return -EINVAL; | |
1281 | ||
8bc92afc KO |
1282 | ret = (opcode == IOCB_CMD_PREADV || |
1283 | opcode == IOCB_CMD_PWRITEV) | |
1284 | ? aio_setup_vectored_rw(req, rw, buf, &nr_segs, | |
1285 | &iovec, compat) | |
1286 | : aio_setup_single_vector(req, rw, buf, &nr_segs, | |
1287 | iovec); | |
eed4e51f | 1288 | if (ret) |
41ef4eb8 KO |
1289 | return ret; |
1290 | ||
1291 | ret = rw_verify_area(rw, file, &req->ki_pos, req->ki_nbytes); | |
8bc92afc KO |
1292 | if (ret < 0) { |
1293 | if (iovec != &inline_vec) | |
1294 | kfree(iovec); | |
41ef4eb8 | 1295 | return ret; |
8bc92afc | 1296 | } |
41ef4eb8 KO |
1297 | |
1298 | req->ki_nbytes = ret; | |
41ef4eb8 | 1299 | |
73a7075e KO |
1300 | /* XXX: move/kill - rw_verify_area()? */ |
1301 | /* This matches the pread()/pwrite() logic */ | |
1302 | if (req->ki_pos < 0) { | |
1303 | ret = -EINVAL; | |
1304 | break; | |
1305 | } | |
1306 | ||
1307 | if (rw == WRITE) | |
1308 | file_start_write(file); | |
1309 | ||
8bc92afc | 1310 | ret = rw_op(req, iovec, nr_segs, req->ki_pos); |
73a7075e KO |
1311 | |
1312 | if (rw == WRITE) | |
1313 | file_end_write(file); | |
1da177e4 | 1314 | break; |
41ef4eb8 | 1315 | |
1da177e4 | 1316 | case IOCB_CMD_FDSYNC: |
41ef4eb8 KO |
1317 | if (!file->f_op->aio_fsync) |
1318 | return -EINVAL; | |
1319 | ||
1320 | ret = file->f_op->aio_fsync(req, 1); | |
1da177e4 | 1321 | break; |
41ef4eb8 | 1322 | |
1da177e4 | 1323 | case IOCB_CMD_FSYNC: |
41ef4eb8 KO |
1324 | if (!file->f_op->aio_fsync) |
1325 | return -EINVAL; | |
1326 | ||
1327 | ret = file->f_op->aio_fsync(req, 0); | |
1da177e4 | 1328 | break; |
41ef4eb8 | 1329 | |
1da177e4 | 1330 | default: |
caf4167a | 1331 | pr_debug("EINVAL: no operation provided\n"); |
41ef4eb8 | 1332 | return -EINVAL; |
1da177e4 LT |
1333 | } |
1334 | ||
8bc92afc KO |
1335 | if (iovec != &inline_vec) |
1336 | kfree(iovec); | |
1337 | ||
41ef4eb8 KO |
1338 | if (ret != -EIOCBQUEUED) { |
1339 | /* | |
1340 | * There's no easy way to restart the syscall since other AIO's | |
1341 | * may be already running. Just fail this IO with EINTR. | |
1342 | */ | |
1343 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || | |
1344 | ret == -ERESTARTNOHAND || | |
1345 | ret == -ERESTART_RESTARTBLOCK)) | |
1346 | ret = -EINTR; | |
1347 | aio_complete(req, ret, 0); | |
1348 | } | |
1da177e4 LT |
1349 | |
1350 | return 0; | |
1351 | } | |
1352 | ||
d5470b59 | 1353 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
a1c8eae7 | 1354 | struct iocb *iocb, bool compat) |
1da177e4 LT |
1355 | { |
1356 | struct kiocb *req; | |
1da177e4 LT |
1357 | ssize_t ret; |
1358 | ||
1359 | /* enforce forwards compatibility on users */ | |
9c3060be | 1360 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
caf4167a | 1361 | pr_debug("EINVAL: reserve field set\n"); |
1da177e4 LT |
1362 | return -EINVAL; |
1363 | } | |
1364 | ||
1365 | /* prevent overflows */ | |
1366 | if (unlikely( | |
1367 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || | |
1368 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || | |
1369 | ((ssize_t)iocb->aio_nbytes < 0) | |
1370 | )) { | |
1371 | pr_debug("EINVAL: io_submit: overflow check\n"); | |
1372 | return -EINVAL; | |
1373 | } | |
1374 | ||
41ef4eb8 | 1375 | req = aio_get_req(ctx); |
1d98ebfc | 1376 | if (unlikely(!req)) |
1da177e4 | 1377 | return -EAGAIN; |
1d98ebfc KO |
1378 | |
1379 | req->ki_filp = fget(iocb->aio_fildes); | |
1380 | if (unlikely(!req->ki_filp)) { | |
1381 | ret = -EBADF; | |
1382 | goto out_put_req; | |
1da177e4 | 1383 | } |
1d98ebfc | 1384 | |
9c3060be DL |
1385 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1386 | /* | |
1387 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an | |
1388 | * instance of the file* now. The file descriptor must be | |
1389 | * an eventfd() fd, and will be signaled for each completed | |
1390 | * event using the eventfd_signal() function. | |
1391 | */ | |
13389010 | 1392 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
801678c5 | 1393 | if (IS_ERR(req->ki_eventfd)) { |
9c3060be | 1394 | ret = PTR_ERR(req->ki_eventfd); |
87c3a86e | 1395 | req->ki_eventfd = NULL; |
9c3060be DL |
1396 | goto out_put_req; |
1397 | } | |
1398 | } | |
1da177e4 | 1399 | |
8a660890 | 1400 | ret = put_user(KIOCB_KEY, &user_iocb->aio_key); |
1da177e4 | 1401 | if (unlikely(ret)) { |
caf4167a | 1402 | pr_debug("EFAULT: aio_key\n"); |
1da177e4 LT |
1403 | goto out_put_req; |
1404 | } | |
1405 | ||
1406 | req->ki_obj.user = user_iocb; | |
1407 | req->ki_user_data = iocb->aio_data; | |
1408 | req->ki_pos = iocb->aio_offset; | |
73a7075e | 1409 | req->ki_nbytes = iocb->aio_nbytes; |
1da177e4 | 1410 | |
8bc92afc KO |
1411 | ret = aio_run_iocb(req, iocb->aio_lio_opcode, |
1412 | (char __user *)(unsigned long)iocb->aio_buf, | |
1413 | compat); | |
41003a7b | 1414 | if (ret) |
7137c6bd | 1415 | goto out_put_req; |
41003a7b | 1416 | |
1da177e4 | 1417 | return 0; |
1da177e4 | 1418 | out_put_req: |
e1bdd5f2 | 1419 | put_reqs_available(ctx, 1); |
e34ecee2 | 1420 | percpu_ref_put(&ctx->reqs); |
57282d8f | 1421 | kiocb_free(req); |
1da177e4 LT |
1422 | return ret; |
1423 | } | |
1424 | ||
9d85cba7 JM |
1425 | long do_io_submit(aio_context_t ctx_id, long nr, |
1426 | struct iocb __user *__user *iocbpp, bool compat) | |
1da177e4 LT |
1427 | { |
1428 | struct kioctx *ctx; | |
1429 | long ret = 0; | |
080d676d | 1430 | int i = 0; |
9f5b9425 | 1431 | struct blk_plug plug; |
1da177e4 LT |
1432 | |
1433 | if (unlikely(nr < 0)) | |
1434 | return -EINVAL; | |
1435 | ||
75e1c70f JM |
1436 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1437 | nr = LONG_MAX/sizeof(*iocbpp); | |
1438 | ||
1da177e4 LT |
1439 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1440 | return -EFAULT; | |
1441 | ||
1442 | ctx = lookup_ioctx(ctx_id); | |
1443 | if (unlikely(!ctx)) { | |
caf4167a | 1444 | pr_debug("EINVAL: invalid context id\n"); |
1da177e4 LT |
1445 | return -EINVAL; |
1446 | } | |
1447 | ||
9f5b9425 SL |
1448 | blk_start_plug(&plug); |
1449 | ||
1da177e4 LT |
1450 | /* |
1451 | * AKPM: should this return a partial result if some of the IOs were | |
1452 | * successfully submitted? | |
1453 | */ | |
1454 | for (i=0; i<nr; i++) { | |
1455 | struct iocb __user *user_iocb; | |
1456 | struct iocb tmp; | |
1457 | ||
1458 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { | |
1459 | ret = -EFAULT; | |
1460 | break; | |
1461 | } | |
1462 | ||
1463 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { | |
1464 | ret = -EFAULT; | |
1465 | break; | |
1466 | } | |
1467 | ||
a1c8eae7 | 1468 | ret = io_submit_one(ctx, user_iocb, &tmp, compat); |
1da177e4 LT |
1469 | if (ret) |
1470 | break; | |
1471 | } | |
9f5b9425 | 1472 | blk_finish_plug(&plug); |
1da177e4 | 1473 | |
723be6e3 | 1474 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1475 | return i ? i : ret; |
1476 | } | |
1477 | ||
9d85cba7 JM |
1478 | /* sys_io_submit: |
1479 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns | |
1480 | * the number of iocbs queued. May return -EINVAL if the aio_context | |
1481 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at | |
1482 | * *iocbpp[0] is not properly initialized, if the operation specified | |
1483 | * is invalid for the file descriptor in the iocb. May fail with | |
1484 | * -EFAULT if any of the data structures point to invalid data. May | |
1485 | * fail with -EBADF if the file descriptor specified in the first | |
1486 | * iocb is invalid. May fail with -EAGAIN if insufficient resources | |
1487 | * are available to queue any iocbs. Will return 0 if nr is 0. Will | |
1488 | * fail with -ENOSYS if not implemented. | |
1489 | */ | |
1490 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, | |
1491 | struct iocb __user * __user *, iocbpp) | |
1492 | { | |
1493 | return do_io_submit(ctx_id, nr, iocbpp, 0); | |
1494 | } | |
1495 | ||
1da177e4 LT |
1496 | /* lookup_kiocb |
1497 | * Finds a given iocb for cancellation. | |
1da177e4 | 1498 | */ |
25ee7e38 AB |
1499 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1500 | u32 key) | |
1da177e4 LT |
1501 | { |
1502 | struct list_head *pos; | |
d00689af ZB |
1503 | |
1504 | assert_spin_locked(&ctx->ctx_lock); | |
1505 | ||
8a660890 KO |
1506 | if (key != KIOCB_KEY) |
1507 | return NULL; | |
1508 | ||
1da177e4 LT |
1509 | /* TODO: use a hash or array, this sucks. */ |
1510 | list_for_each(pos, &ctx->active_reqs) { | |
1511 | struct kiocb *kiocb = list_kiocb(pos); | |
8a660890 | 1512 | if (kiocb->ki_obj.user == iocb) |
1da177e4 LT |
1513 | return kiocb; |
1514 | } | |
1515 | return NULL; | |
1516 | } | |
1517 | ||
1518 | /* sys_io_cancel: | |
1519 | * Attempts to cancel an iocb previously passed to io_submit. If | |
1520 | * the operation is successfully cancelled, the resulting event is | |
1521 | * copied into the memory pointed to by result without being placed | |
1522 | * into the completion queue and 0 is returned. May fail with | |
1523 | * -EFAULT if any of the data structures pointed to are invalid. | |
1524 | * May fail with -EINVAL if aio_context specified by ctx_id is | |
1525 | * invalid. May fail with -EAGAIN if the iocb specified was not | |
1526 | * cancelled. Will fail with -ENOSYS if not implemented. | |
1527 | */ | |
002c8976 HC |
1528 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1529 | struct io_event __user *, result) | |
1da177e4 | 1530 | { |
1da177e4 LT |
1531 | struct kioctx *ctx; |
1532 | struct kiocb *kiocb; | |
1533 | u32 key; | |
1534 | int ret; | |
1535 | ||
1536 | ret = get_user(key, &iocb->aio_key); | |
1537 | if (unlikely(ret)) | |
1538 | return -EFAULT; | |
1539 | ||
1540 | ctx = lookup_ioctx(ctx_id); | |
1541 | if (unlikely(!ctx)) | |
1542 | return -EINVAL; | |
1543 | ||
1544 | spin_lock_irq(&ctx->ctx_lock); | |
906b973c | 1545 | |
1da177e4 | 1546 | kiocb = lookup_kiocb(ctx, iocb, key); |
906b973c | 1547 | if (kiocb) |
bec68faa | 1548 | ret = kiocb_cancel(ctx, kiocb); |
906b973c KO |
1549 | else |
1550 | ret = -EINVAL; | |
1551 | ||
1da177e4 LT |
1552 | spin_unlock_irq(&ctx->ctx_lock); |
1553 | ||
906b973c | 1554 | if (!ret) { |
bec68faa KO |
1555 | /* |
1556 | * The result argument is no longer used - the io_event is | |
1557 | * always delivered via the ring buffer. -EINPROGRESS indicates | |
1558 | * cancellation is progress: | |
906b973c | 1559 | */ |
bec68faa | 1560 | ret = -EINPROGRESS; |
906b973c | 1561 | } |
1da177e4 | 1562 | |
723be6e3 | 1563 | percpu_ref_put(&ctx->users); |
1da177e4 LT |
1564 | |
1565 | return ret; | |
1566 | } | |
1567 | ||
1568 | /* io_getevents: | |
1569 | * Attempts to read at least min_nr events and up to nr events from | |
642b5123 ST |
1570 | * the completion queue for the aio_context specified by ctx_id. If |
1571 | * it succeeds, the number of read events is returned. May fail with | |
1572 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is | |
1573 | * out of range, if timeout is out of range. May fail with -EFAULT | |
1574 | * if any of the memory specified is invalid. May return 0 or | |
1575 | * < min_nr if the timeout specified by timeout has elapsed | |
1576 | * before sufficient events are available, where timeout == NULL | |
1577 | * specifies an infinite timeout. Note that the timeout pointed to by | |
6900807c | 1578 | * timeout is relative. Will fail with -ENOSYS if not implemented. |
1da177e4 | 1579 | */ |
002c8976 HC |
1580 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1581 | long, min_nr, | |
1582 | long, nr, | |
1583 | struct io_event __user *, events, | |
1584 | struct timespec __user *, timeout) | |
1da177e4 LT |
1585 | { |
1586 | struct kioctx *ioctx = lookup_ioctx(ctx_id); | |
1587 | long ret = -EINVAL; | |
1588 | ||
1589 | if (likely(ioctx)) { | |
2e410255 | 1590 | if (likely(min_nr <= nr && min_nr >= 0)) |
1da177e4 | 1591 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
723be6e3 | 1592 | percpu_ref_put(&ioctx->users); |
1da177e4 | 1593 | } |
1da177e4 LT |
1594 | return ret; |
1595 | } |