Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | */ |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/time.h> |
| 15 | #include <linux/aio_abi.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/syscalls.h> |
| 18 | |
| 19 | #define DEBUG 0 |
| 20 | |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/file.h> |
| 24 | #include <linux/mm.h> |
| 25 | #include <linux/mman.h> |
| 26 | #include <linux/slab.h> |
| 27 | #include <linux/timer.h> |
| 28 | #include <linux/aio.h> |
| 29 | #include <linux/highmem.h> |
| 30 | #include <linux/workqueue.h> |
| 31 | #include <linux/security.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 32 | #include <linux/rcuref.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | |
| 34 | #include <asm/kmap_types.h> |
| 35 | #include <asm/uaccess.h> |
| 36 | #include <asm/mmu_context.h> |
| 37 | |
| 38 | #if DEBUG > 1 |
| 39 | #define dprintk printk |
| 40 | #else |
| 41 | #define dprintk(x...) do { ; } while (0) |
| 42 | #endif |
| 43 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | /*------ sysctl variables----*/ |
| 45 | atomic_t aio_nr = ATOMIC_INIT(0); /* current system wide number of aio requests */ |
| 46 | unsigned aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ |
| 47 | /*----end sysctl variables---*/ |
| 48 | |
| 49 | static kmem_cache_t *kiocb_cachep; |
| 50 | static kmem_cache_t *kioctx_cachep; |
| 51 | |
| 52 | static struct workqueue_struct *aio_wq; |
| 53 | |
| 54 | /* Used for rare fput completion. */ |
| 55 | static void aio_fput_routine(void *); |
| 56 | static DECLARE_WORK(fput_work, aio_fput_routine, NULL); |
| 57 | |
| 58 | static DEFINE_SPINLOCK(fput_lock); |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 59 | static LIST_HEAD(fput_head); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
| 61 | static void aio_kick_handler(void *); |
Sébastien Dugu | c016e22 | 2005-06-28 20:44:59 -0700 | [diff] [blame] | 62 | static void aio_queue_work(struct kioctx *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | /* aio_setup |
| 65 | * Creates the slab caches used by the aio routines, panic on |
| 66 | * failure as this is done early during the boot sequence. |
| 67 | */ |
| 68 | static int __init aio_setup(void) |
| 69 | { |
| 70 | kiocb_cachep = kmem_cache_create("kiocb", sizeof(struct kiocb), |
| 71 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 72 | kioctx_cachep = kmem_cache_create("kioctx", sizeof(struct kioctx), |
| 73 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 74 | |
| 75 | aio_wq = create_workqueue("aio"); |
| 76 | |
| 77 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
| 78 | |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | static void aio_free_ring(struct kioctx *ctx) |
| 83 | { |
| 84 | struct aio_ring_info *info = &ctx->ring_info; |
| 85 | long i; |
| 86 | |
| 87 | for (i=0; i<info->nr_pages; i++) |
| 88 | put_page(info->ring_pages[i]); |
| 89 | |
| 90 | if (info->mmap_size) { |
| 91 | down_write(&ctx->mm->mmap_sem); |
| 92 | do_munmap(ctx->mm, info->mmap_base, info->mmap_size); |
| 93 | up_write(&ctx->mm->mmap_sem); |
| 94 | } |
| 95 | |
| 96 | if (info->ring_pages && info->ring_pages != info->internal_pages) |
| 97 | kfree(info->ring_pages); |
| 98 | info->ring_pages = NULL; |
| 99 | info->nr = 0; |
| 100 | } |
| 101 | |
| 102 | static int aio_setup_ring(struct kioctx *ctx) |
| 103 | { |
| 104 | struct aio_ring *ring; |
| 105 | struct aio_ring_info *info = &ctx->ring_info; |
| 106 | unsigned nr_events = ctx->max_reqs; |
| 107 | unsigned long size; |
| 108 | int nr_pages; |
| 109 | |
| 110 | /* Compensate for the ring buffer's head/tail overlap entry */ |
| 111 | nr_events += 2; /* 1 is required, 2 for good luck */ |
| 112 | |
| 113 | size = sizeof(struct aio_ring); |
| 114 | size += sizeof(struct io_event) * nr_events; |
| 115 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
| 116 | |
| 117 | if (nr_pages < 0) |
| 118 | return -EINVAL; |
| 119 | |
| 120 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
| 121 | |
| 122 | info->nr = 0; |
| 123 | info->ring_pages = info->internal_pages; |
| 124 | if (nr_pages > AIO_RING_PAGES) { |
| 125 | info->ring_pages = kmalloc(sizeof(struct page *) * nr_pages, GFP_KERNEL); |
| 126 | if (!info->ring_pages) |
| 127 | return -ENOMEM; |
| 128 | memset(info->ring_pages, 0, sizeof(struct page *) * nr_pages); |
| 129 | } |
| 130 | |
| 131 | info->mmap_size = nr_pages * PAGE_SIZE; |
| 132 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
| 133 | down_write(&ctx->mm->mmap_sem); |
| 134 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, |
| 135 | PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, |
| 136 | 0); |
| 137 | if (IS_ERR((void *)info->mmap_base)) { |
| 138 | up_write(&ctx->mm->mmap_sem); |
| 139 | printk("mmap err: %ld\n", -info->mmap_base); |
| 140 | info->mmap_size = 0; |
| 141 | aio_free_ring(ctx); |
| 142 | return -EAGAIN; |
| 143 | } |
| 144 | |
| 145 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
| 146 | info->nr_pages = get_user_pages(current, ctx->mm, |
| 147 | info->mmap_base, nr_pages, |
| 148 | 1, 0, info->ring_pages, NULL); |
| 149 | up_write(&ctx->mm->mmap_sem); |
| 150 | |
| 151 | if (unlikely(info->nr_pages != nr_pages)) { |
| 152 | aio_free_ring(ctx); |
| 153 | return -EAGAIN; |
| 154 | } |
| 155 | |
| 156 | ctx->user_id = info->mmap_base; |
| 157 | |
| 158 | info->nr = nr_events; /* trusted copy */ |
| 159 | |
| 160 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
| 161 | ring->nr = nr_events; /* user copy */ |
| 162 | ring->id = ctx->user_id; |
| 163 | ring->head = ring->tail = 0; |
| 164 | ring->magic = AIO_RING_MAGIC; |
| 165 | ring->compat_features = AIO_RING_COMPAT_FEATURES; |
| 166 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; |
| 167 | ring->header_length = sizeof(struct aio_ring); |
| 168 | kunmap_atomic(ring, KM_USER0); |
| 169 | |
| 170 | return 0; |
| 171 | } |
| 172 | |
| 173 | |
| 174 | /* aio_ring_event: returns a pointer to the event at the given index from |
| 175 | * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); |
| 176 | */ |
| 177 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
| 178 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) |
| 179 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) |
| 180 | |
| 181 | #define aio_ring_event(info, nr, km) ({ \ |
| 182 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ |
| 183 | struct io_event *__event; \ |
| 184 | __event = kmap_atomic( \ |
| 185 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ |
| 186 | __event += pos % AIO_EVENTS_PER_PAGE; \ |
| 187 | __event; \ |
| 188 | }) |
| 189 | |
| 190 | #define put_aio_ring_event(event, km) do { \ |
| 191 | struct io_event *__event = (event); \ |
| 192 | (void)__event; \ |
| 193 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ |
| 194 | } while(0) |
| 195 | |
| 196 | /* ioctx_alloc |
| 197 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
| 198 | */ |
| 199 | static struct kioctx *ioctx_alloc(unsigned nr_events) |
| 200 | { |
| 201 | struct mm_struct *mm; |
| 202 | struct kioctx *ctx; |
| 203 | |
| 204 | /* Prevent overflows */ |
| 205 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
| 206 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
| 207 | pr_debug("ENOMEM: nr_events too high\n"); |
| 208 | return ERR_PTR(-EINVAL); |
| 209 | } |
| 210 | |
| 211 | if (nr_events > aio_max_nr) |
| 212 | return ERR_PTR(-EAGAIN); |
| 213 | |
| 214 | ctx = kmem_cache_alloc(kioctx_cachep, GFP_KERNEL); |
| 215 | if (!ctx) |
| 216 | return ERR_PTR(-ENOMEM); |
| 217 | |
| 218 | memset(ctx, 0, sizeof(*ctx)); |
| 219 | ctx->max_reqs = nr_events; |
| 220 | mm = ctx->mm = current->mm; |
| 221 | atomic_inc(&mm->mm_count); |
| 222 | |
| 223 | atomic_set(&ctx->users, 1); |
| 224 | spin_lock_init(&ctx->ctx_lock); |
| 225 | spin_lock_init(&ctx->ring_info.ring_lock); |
| 226 | init_waitqueue_head(&ctx->wait); |
| 227 | |
| 228 | INIT_LIST_HEAD(&ctx->active_reqs); |
| 229 | INIT_LIST_HEAD(&ctx->run_list); |
| 230 | INIT_WORK(&ctx->wq, aio_kick_handler, ctx); |
| 231 | |
| 232 | if (aio_setup_ring(ctx) < 0) |
| 233 | goto out_freectx; |
| 234 | |
| 235 | /* limit the number of system wide aios */ |
| 236 | atomic_add(ctx->max_reqs, &aio_nr); /* undone by __put_ioctx */ |
| 237 | if (unlikely(atomic_read(&aio_nr) > aio_max_nr)) |
| 238 | goto out_cleanup; |
| 239 | |
| 240 | /* now link into global list. kludge. FIXME */ |
| 241 | write_lock(&mm->ioctx_list_lock); |
| 242 | ctx->next = mm->ioctx_list; |
| 243 | mm->ioctx_list = ctx; |
| 244 | write_unlock(&mm->ioctx_list_lock); |
| 245 | |
| 246 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
| 247 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
| 248 | return ctx; |
| 249 | |
| 250 | out_cleanup: |
| 251 | atomic_sub(ctx->max_reqs, &aio_nr); |
| 252 | ctx->max_reqs = 0; /* prevent __put_ioctx from sub'ing aio_nr */ |
| 253 | __put_ioctx(ctx); |
| 254 | return ERR_PTR(-EAGAIN); |
| 255 | |
| 256 | out_freectx: |
| 257 | mmdrop(mm); |
| 258 | kmem_cache_free(kioctx_cachep, ctx); |
| 259 | ctx = ERR_PTR(-ENOMEM); |
| 260 | |
| 261 | dprintk("aio: error allocating ioctx %p\n", ctx); |
| 262 | return ctx; |
| 263 | } |
| 264 | |
| 265 | /* aio_cancel_all |
| 266 | * Cancels all outstanding aio requests on an aio context. Used |
| 267 | * when the processes owning a context have all exited to encourage |
| 268 | * the rapid destruction of the kioctx. |
| 269 | */ |
| 270 | static void aio_cancel_all(struct kioctx *ctx) |
| 271 | { |
| 272 | int (*cancel)(struct kiocb *, struct io_event *); |
| 273 | struct io_event res; |
| 274 | spin_lock_irq(&ctx->ctx_lock); |
| 275 | ctx->dead = 1; |
| 276 | while (!list_empty(&ctx->active_reqs)) { |
| 277 | struct list_head *pos = ctx->active_reqs.next; |
| 278 | struct kiocb *iocb = list_kiocb(pos); |
| 279 | list_del_init(&iocb->ki_list); |
| 280 | cancel = iocb->ki_cancel; |
| 281 | kiocbSetCancelled(iocb); |
| 282 | if (cancel) { |
| 283 | iocb->ki_users++; |
| 284 | spin_unlock_irq(&ctx->ctx_lock); |
| 285 | cancel(iocb, &res); |
| 286 | spin_lock_irq(&ctx->ctx_lock); |
| 287 | } |
| 288 | } |
| 289 | spin_unlock_irq(&ctx->ctx_lock); |
| 290 | } |
| 291 | |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 292 | static void wait_for_all_aios(struct kioctx *ctx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | { |
| 294 | struct task_struct *tsk = current; |
| 295 | DECLARE_WAITQUEUE(wait, tsk); |
| 296 | |
| 297 | if (!ctx->reqs_active) |
| 298 | return; |
| 299 | |
| 300 | add_wait_queue(&ctx->wait, &wait); |
| 301 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| 302 | while (ctx->reqs_active) { |
| 303 | schedule(); |
| 304 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| 305 | } |
| 306 | __set_task_state(tsk, TASK_RUNNING); |
| 307 | remove_wait_queue(&ctx->wait, &wait); |
| 308 | } |
| 309 | |
| 310 | /* wait_on_sync_kiocb: |
| 311 | * Waits on the given sync kiocb to complete. |
| 312 | */ |
| 313 | ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb) |
| 314 | { |
| 315 | while (iocb->ki_users) { |
| 316 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 317 | if (!iocb->ki_users) |
| 318 | break; |
| 319 | schedule(); |
| 320 | } |
| 321 | __set_current_state(TASK_RUNNING); |
| 322 | return iocb->ki_user_data; |
| 323 | } |
| 324 | |
| 325 | /* exit_aio: called when the last user of mm goes away. At this point, |
| 326 | * there is no way for any new requests to be submited or any of the |
| 327 | * io_* syscalls to be called on the context. However, there may be |
| 328 | * outstanding requests which hold references to the context; as they |
| 329 | * go away, they will call put_ioctx and release any pinned memory |
| 330 | * associated with the request (held via struct page * references). |
| 331 | */ |
| 332 | void fastcall exit_aio(struct mm_struct *mm) |
| 333 | { |
| 334 | struct kioctx *ctx = mm->ioctx_list; |
| 335 | mm->ioctx_list = NULL; |
| 336 | while (ctx) { |
| 337 | struct kioctx *next = ctx->next; |
| 338 | ctx->next = NULL; |
| 339 | aio_cancel_all(ctx); |
| 340 | |
| 341 | wait_for_all_aios(ctx); |
| 342 | /* |
| 343 | * this is an overkill, but ensures we don't leave |
| 344 | * the ctx on the aio_wq |
| 345 | */ |
| 346 | flush_workqueue(aio_wq); |
| 347 | |
| 348 | if (1 != atomic_read(&ctx->users)) |
| 349 | printk(KERN_DEBUG |
| 350 | "exit_aio:ioctx still alive: %d %d %d\n", |
| 351 | atomic_read(&ctx->users), ctx->dead, |
| 352 | ctx->reqs_active); |
| 353 | put_ioctx(ctx); |
| 354 | ctx = next; |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | /* __put_ioctx |
| 359 | * Called when the last user of an aio context has gone away, |
| 360 | * and the struct needs to be freed. |
| 361 | */ |
| 362 | void fastcall __put_ioctx(struct kioctx *ctx) |
| 363 | { |
| 364 | unsigned nr_events = ctx->max_reqs; |
| 365 | |
| 366 | if (unlikely(ctx->reqs_active)) |
| 367 | BUG(); |
| 368 | |
| 369 | cancel_delayed_work(&ctx->wq); |
| 370 | flush_workqueue(aio_wq); |
| 371 | aio_free_ring(ctx); |
| 372 | mmdrop(ctx->mm); |
| 373 | ctx->mm = NULL; |
| 374 | pr_debug("__put_ioctx: freeing %p\n", ctx); |
| 375 | kmem_cache_free(kioctx_cachep, ctx); |
| 376 | |
| 377 | atomic_sub(nr_events, &aio_nr); |
| 378 | } |
| 379 | |
| 380 | /* aio_get_req |
| 381 | * Allocate a slot for an aio request. Increments the users count |
| 382 | * of the kioctx so that the kioctx stays around until all requests are |
| 383 | * complete. Returns NULL if no requests are free. |
| 384 | * |
| 385 | * Returns with kiocb->users set to 2. The io submit code path holds |
| 386 | * an extra reference while submitting the i/o. |
| 387 | * This prevents races between the aio code path referencing the |
| 388 | * req (after submitting it) and aio_complete() freeing the req. |
| 389 | */ |
| 390 | static struct kiocb *FASTCALL(__aio_get_req(struct kioctx *ctx)); |
| 391 | static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx) |
| 392 | { |
| 393 | struct kiocb *req = NULL; |
| 394 | struct aio_ring *ring; |
| 395 | int okay = 0; |
| 396 | |
| 397 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
| 398 | if (unlikely(!req)) |
| 399 | return NULL; |
| 400 | |
Zach Brown | 4faa528 | 2005-10-17 16:43:33 -0700 | [diff] [blame^] | 401 | req->ki_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | req->ki_users = 2; |
| 403 | req->ki_key = 0; |
| 404 | req->ki_ctx = ctx; |
| 405 | req->ki_cancel = NULL; |
| 406 | req->ki_retry = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | req->ki_dtor = NULL; |
| 408 | req->private = NULL; |
| 409 | INIT_LIST_HEAD(&req->ki_run_list); |
| 410 | |
| 411 | /* Check if the completion queue has enough free space to |
| 412 | * accept an event from this io. |
| 413 | */ |
| 414 | spin_lock_irq(&ctx->ctx_lock); |
| 415 | ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0); |
| 416 | if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) { |
| 417 | list_add(&req->ki_list, &ctx->active_reqs); |
| 418 | get_ioctx(ctx); |
| 419 | ctx->reqs_active++; |
| 420 | okay = 1; |
| 421 | } |
| 422 | kunmap_atomic(ring, KM_USER0); |
| 423 | spin_unlock_irq(&ctx->ctx_lock); |
| 424 | |
| 425 | if (!okay) { |
| 426 | kmem_cache_free(kiocb_cachep, req); |
| 427 | req = NULL; |
| 428 | } |
| 429 | |
| 430 | return req; |
| 431 | } |
| 432 | |
| 433 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
| 434 | { |
| 435 | struct kiocb *req; |
| 436 | /* Handle a potential starvation case -- should be exceedingly rare as |
| 437 | * requests will be stuck on fput_head only if the aio_fput_routine is |
| 438 | * delayed and the requests were the last user of the struct file. |
| 439 | */ |
| 440 | req = __aio_get_req(ctx); |
| 441 | if (unlikely(NULL == req)) { |
| 442 | aio_fput_routine(NULL); |
| 443 | req = __aio_get_req(ctx); |
| 444 | } |
| 445 | return req; |
| 446 | } |
| 447 | |
| 448 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
| 449 | { |
| 450 | if (req->ki_dtor) |
| 451 | req->ki_dtor(req); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | kmem_cache_free(kiocb_cachep, req); |
| 453 | ctx->reqs_active--; |
| 454 | |
| 455 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
| 456 | wake_up(&ctx->wait); |
| 457 | } |
| 458 | |
| 459 | static void aio_fput_routine(void *data) |
| 460 | { |
| 461 | spin_lock_irq(&fput_lock); |
| 462 | while (likely(!list_empty(&fput_head))) { |
| 463 | struct kiocb *req = list_kiocb(fput_head.next); |
| 464 | struct kioctx *ctx = req->ki_ctx; |
| 465 | |
| 466 | list_del(&req->ki_list); |
| 467 | spin_unlock_irq(&fput_lock); |
| 468 | |
| 469 | /* Complete the fput */ |
| 470 | __fput(req->ki_filp); |
| 471 | |
| 472 | /* Link the iocb into the context's free list */ |
| 473 | spin_lock_irq(&ctx->ctx_lock); |
| 474 | really_put_req(ctx, req); |
| 475 | spin_unlock_irq(&ctx->ctx_lock); |
| 476 | |
| 477 | put_ioctx(ctx); |
| 478 | spin_lock_irq(&fput_lock); |
| 479 | } |
| 480 | spin_unlock_irq(&fput_lock); |
| 481 | } |
| 482 | |
| 483 | /* __aio_put_req |
| 484 | * Returns true if this put was the last user of the request. |
| 485 | */ |
| 486 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
| 487 | { |
| 488 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n", |
| 489 | req, atomic_read(&req->ki_filp->f_count)); |
| 490 | |
| 491 | req->ki_users --; |
| 492 | if (unlikely(req->ki_users < 0)) |
| 493 | BUG(); |
| 494 | if (likely(req->ki_users)) |
| 495 | return 0; |
| 496 | list_del(&req->ki_list); /* remove from active_reqs */ |
| 497 | req->ki_cancel = NULL; |
| 498 | req->ki_retry = NULL; |
| 499 | |
| 500 | /* Must be done under the lock to serialise against cancellation. |
| 501 | * Call this aio_fput as it duplicates fput via the fput_work. |
| 502 | */ |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 503 | if (unlikely(rcuref_dec_and_test(&req->ki_filp->f_count))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | get_ioctx(ctx); |
| 505 | spin_lock(&fput_lock); |
| 506 | list_add(&req->ki_list, &fput_head); |
| 507 | spin_unlock(&fput_lock); |
| 508 | queue_work(aio_wq, &fput_work); |
| 509 | } else |
| 510 | really_put_req(ctx, req); |
| 511 | return 1; |
| 512 | } |
| 513 | |
| 514 | /* aio_put_req |
| 515 | * Returns true if this put was the last user of the kiocb, |
| 516 | * false if the request is still in use. |
| 517 | */ |
| 518 | int fastcall aio_put_req(struct kiocb *req) |
| 519 | { |
| 520 | struct kioctx *ctx = req->ki_ctx; |
| 521 | int ret; |
| 522 | spin_lock_irq(&ctx->ctx_lock); |
| 523 | ret = __aio_put_req(ctx, req); |
| 524 | spin_unlock_irq(&ctx->ctx_lock); |
| 525 | if (ret) |
| 526 | put_ioctx(ctx); |
| 527 | return ret; |
| 528 | } |
| 529 | |
| 530 | /* Lookup an ioctx id. ioctx_list is lockless for reads. |
| 531 | * FIXME: this is O(n) and is only suitable for development. |
| 532 | */ |
| 533 | struct kioctx *lookup_ioctx(unsigned long ctx_id) |
| 534 | { |
| 535 | struct kioctx *ioctx; |
| 536 | struct mm_struct *mm; |
| 537 | |
| 538 | mm = current->mm; |
| 539 | read_lock(&mm->ioctx_list_lock); |
| 540 | for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next) |
| 541 | if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) { |
| 542 | get_ioctx(ioctx); |
| 543 | break; |
| 544 | } |
| 545 | read_unlock(&mm->ioctx_list_lock); |
| 546 | |
| 547 | return ioctx; |
| 548 | } |
| 549 | |
| 550 | /* |
| 551 | * use_mm |
| 552 | * Makes the calling kernel thread take on the specified |
| 553 | * mm context. |
| 554 | * Called by the retry thread execute retries within the |
| 555 | * iocb issuer's mm context, so that copy_from/to_user |
| 556 | * operations work seamlessly for aio. |
| 557 | * (Note: this routine is intended to be called only |
| 558 | * from a kernel thread context) |
| 559 | */ |
| 560 | static void use_mm(struct mm_struct *mm) |
| 561 | { |
| 562 | struct mm_struct *active_mm; |
| 563 | struct task_struct *tsk = current; |
| 564 | |
| 565 | task_lock(tsk); |
| 566 | tsk->flags |= PF_BORROWED_MM; |
| 567 | active_mm = tsk->active_mm; |
| 568 | atomic_inc(&mm->mm_count); |
| 569 | tsk->mm = mm; |
| 570 | tsk->active_mm = mm; |
Paolo 'Blaisorblade' Giarrusso | 1e40cd3 | 2005-09-03 15:57:25 -0700 | [diff] [blame] | 571 | /* |
| 572 | * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise |
| 573 | * it won't work. Update it accordingly if you change it here |
| 574 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | activate_mm(active_mm, mm); |
| 576 | task_unlock(tsk); |
| 577 | |
| 578 | mmdrop(active_mm); |
| 579 | } |
| 580 | |
| 581 | /* |
| 582 | * unuse_mm |
| 583 | * Reverses the effect of use_mm, i.e. releases the |
| 584 | * specified mm context which was earlier taken on |
| 585 | * by the calling kernel thread |
| 586 | * (Note: this routine is intended to be called only |
| 587 | * from a kernel thread context) |
| 588 | * |
| 589 | * Comments: Called with ctx->ctx_lock held. This nests |
| 590 | * task_lock instead ctx_lock. |
| 591 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 592 | static void unuse_mm(struct mm_struct *mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | { |
| 594 | struct task_struct *tsk = current; |
| 595 | |
| 596 | task_lock(tsk); |
| 597 | tsk->flags &= ~PF_BORROWED_MM; |
| 598 | tsk->mm = NULL; |
| 599 | /* active_mm is still 'mm' */ |
| 600 | enter_lazy_tlb(mm, tsk); |
| 601 | task_unlock(tsk); |
| 602 | } |
| 603 | |
| 604 | /* |
| 605 | * Queue up a kiocb to be retried. Assumes that the kiocb |
| 606 | * has already been marked as kicked, and places it on |
| 607 | * the retry run list for the corresponding ioctx, if it |
| 608 | * isn't already queued. Returns 1 if it actually queued |
| 609 | * the kiocb (to tell the caller to activate the work |
| 610 | * queue to process it), or 0, if it found that it was |
| 611 | * already queued. |
| 612 | * |
| 613 | * Should be called with the spin lock iocb->ki_ctx->ctx_lock |
| 614 | * held |
| 615 | */ |
| 616 | static inline int __queue_kicked_iocb(struct kiocb *iocb) |
| 617 | { |
| 618 | struct kioctx *ctx = iocb->ki_ctx; |
| 619 | |
| 620 | if (list_empty(&iocb->ki_run_list)) { |
| 621 | list_add_tail(&iocb->ki_run_list, |
| 622 | &ctx->run_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | return 1; |
| 624 | } |
| 625 | return 0; |
| 626 | } |
| 627 | |
| 628 | /* aio_run_iocb |
| 629 | * This is the core aio execution routine. It is |
| 630 | * invoked both for initial i/o submission and |
| 631 | * subsequent retries via the aio_kick_handler. |
| 632 | * Expects to be invoked with iocb->ki_ctx->lock |
| 633 | * already held. The lock is released and reaquired |
| 634 | * as needed during processing. |
| 635 | * |
| 636 | * Calls the iocb retry method (already setup for the |
| 637 | * iocb on initial submission) for operation specific |
| 638 | * handling, but takes care of most of common retry |
| 639 | * execution details for a given iocb. The retry method |
| 640 | * needs to be non-blocking as far as possible, to avoid |
| 641 | * holding up other iocbs waiting to be serviced by the |
| 642 | * retry kernel thread. |
| 643 | * |
| 644 | * The trickier parts in this code have to do with |
| 645 | * ensuring that only one retry instance is in progress |
| 646 | * for a given iocb at any time. Providing that guarantee |
| 647 | * simplifies the coding of individual aio operations as |
| 648 | * it avoids various potential races. |
| 649 | */ |
| 650 | static ssize_t aio_run_iocb(struct kiocb *iocb) |
| 651 | { |
| 652 | struct kioctx *ctx = iocb->ki_ctx; |
| 653 | ssize_t (*retry)(struct kiocb *); |
| 654 | ssize_t ret; |
| 655 | |
| 656 | if (iocb->ki_retried++ > 1024*1024) { |
| 657 | printk("Maximal retry count. Bytes done %Zd\n", |
| 658 | iocb->ki_nbytes - iocb->ki_left); |
| 659 | return -EAGAIN; |
| 660 | } |
| 661 | |
| 662 | if (!(iocb->ki_retried & 0xff)) { |
Ken Chen | 644d3a0 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 663 | pr_debug("%ld retry: %d of %d\n", iocb->ki_retried, |
| 664 | iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | } |
| 666 | |
| 667 | if (!(retry = iocb->ki_retry)) { |
| 668 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
| 669 | return 0; |
| 670 | } |
| 671 | |
| 672 | /* |
| 673 | * We don't want the next retry iteration for this |
| 674 | * operation to start until this one has returned and |
| 675 | * updated the iocb state. However, wait_queue functions |
| 676 | * can trigger a kick_iocb from interrupt context in the |
| 677 | * meantime, indicating that data is available for the next |
| 678 | * iteration. We want to remember that and enable the |
| 679 | * next retry iteration _after_ we are through with |
| 680 | * this one. |
| 681 | * |
| 682 | * So, in order to be able to register a "kick", but |
| 683 | * prevent it from being queued now, we clear the kick |
| 684 | * flag, but make the kick code *think* that the iocb is |
| 685 | * still on the run list until we are actually done. |
| 686 | * When we are done with this iteration, we check if |
| 687 | * the iocb was kicked in the meantime and if so, queue |
| 688 | * it up afresh. |
| 689 | */ |
| 690 | |
| 691 | kiocbClearKicked(iocb); |
| 692 | |
| 693 | /* |
| 694 | * This is so that aio_complete knows it doesn't need to |
| 695 | * pull the iocb off the run list (We can't just call |
| 696 | * INIT_LIST_HEAD because we don't want a kick_iocb to |
| 697 | * queue this on the run list yet) |
| 698 | */ |
| 699 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
| 700 | spin_unlock_irq(&ctx->ctx_lock); |
| 701 | |
| 702 | /* Quit retrying if the i/o has been cancelled */ |
| 703 | if (kiocbIsCancelled(iocb)) { |
| 704 | ret = -EINTR; |
| 705 | aio_complete(iocb, ret, 0); |
| 706 | /* must not access the iocb after this */ |
| 707 | goto out; |
| 708 | } |
| 709 | |
| 710 | /* |
| 711 | * Now we are all set to call the retry method in async |
| 712 | * context. By setting this thread's io_wait context |
| 713 | * to point to the wait queue entry inside the currently |
| 714 | * running iocb for the duration of the retry, we ensure |
| 715 | * that async notification wakeups are queued by the |
| 716 | * operation instead of blocking waits, and when notified, |
| 717 | * cause the iocb to be kicked for continuation (through |
| 718 | * the aio_wake_function callback). |
| 719 | */ |
| 720 | BUG_ON(current->io_wait != NULL); |
| 721 | current->io_wait = &iocb->ki_wait; |
| 722 | ret = retry(iocb); |
| 723 | current->io_wait = NULL; |
| 724 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 725 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
| 726 | BUG_ON(!list_empty(&iocb->ki_wait.task_list)); |
| 727 | aio_complete(iocb, ret, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | } |
| 729 | out: |
| 730 | spin_lock_irq(&ctx->ctx_lock); |
| 731 | |
| 732 | if (-EIOCBRETRY == ret) { |
| 733 | /* |
| 734 | * OK, now that we are done with this iteration |
| 735 | * and know that there is more left to go, |
| 736 | * this is where we let go so that a subsequent |
| 737 | * "kick" can start the next iteration |
| 738 | */ |
| 739 | |
| 740 | /* will make __queue_kicked_iocb succeed from here on */ |
| 741 | INIT_LIST_HEAD(&iocb->ki_run_list); |
| 742 | /* we must queue the next iteration ourselves, if it |
| 743 | * has already been kicked */ |
| 744 | if (kiocbIsKicked(iocb)) { |
| 745 | __queue_kicked_iocb(iocb); |
Sébastien Dugu | c016e22 | 2005-06-28 20:44:59 -0700 | [diff] [blame] | 746 | |
| 747 | /* |
| 748 | * __queue_kicked_iocb will always return 1 here, because |
| 749 | * iocb->ki_run_list is empty at this point so it should |
| 750 | * be safe to unconditionally queue the context into the |
| 751 | * work queue. |
| 752 | */ |
| 753 | aio_queue_work(ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 754 | } |
| 755 | } |
| 756 | return ret; |
| 757 | } |
| 758 | |
| 759 | /* |
| 760 | * __aio_run_iocbs: |
| 761 | * Process all pending retries queued on the ioctx |
| 762 | * run list. |
| 763 | * Assumes it is operating within the aio issuer's mm |
| 764 | * context. Expects to be called with ctx->ctx_lock held |
| 765 | */ |
| 766 | static int __aio_run_iocbs(struct kioctx *ctx) |
| 767 | { |
| 768 | struct kiocb *iocb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | LIST_HEAD(run_list); |
| 770 | |
| 771 | list_splice_init(&ctx->run_list, &run_list); |
| 772 | while (!list_empty(&run_list)) { |
| 773 | iocb = list_entry(run_list.next, struct kiocb, |
| 774 | ki_run_list); |
| 775 | list_del(&iocb->ki_run_list); |
| 776 | /* |
| 777 | * Hold an extra reference while retrying i/o. |
| 778 | */ |
| 779 | iocb->ki_users++; /* grab extra reference */ |
| 780 | aio_run_iocb(iocb); |
| 781 | if (__aio_put_req(ctx, iocb)) /* drop extra ref */ |
| 782 | put_ioctx(ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | if (!list_empty(&ctx->run_list)) |
| 785 | return 1; |
| 786 | return 0; |
| 787 | } |
| 788 | |
| 789 | static void aio_queue_work(struct kioctx * ctx) |
| 790 | { |
| 791 | unsigned long timeout; |
| 792 | /* |
| 793 | * if someone is waiting, get the work started right |
| 794 | * away, otherwise, use a longer delay |
| 795 | */ |
| 796 | smp_mb(); |
| 797 | if (waitqueue_active(&ctx->wait)) |
| 798 | timeout = 1; |
| 799 | else |
| 800 | timeout = HZ/10; |
| 801 | queue_delayed_work(aio_wq, &ctx->wq, timeout); |
| 802 | } |
| 803 | |
| 804 | |
| 805 | /* |
| 806 | * aio_run_iocbs: |
| 807 | * Process all pending retries queued on the ioctx |
| 808 | * run list. |
| 809 | * Assumes it is operating within the aio issuer's mm |
| 810 | * context. |
| 811 | */ |
| 812 | static inline void aio_run_iocbs(struct kioctx *ctx) |
| 813 | { |
| 814 | int requeue; |
| 815 | |
| 816 | spin_lock_irq(&ctx->ctx_lock); |
| 817 | |
| 818 | requeue = __aio_run_iocbs(ctx); |
| 819 | spin_unlock_irq(&ctx->ctx_lock); |
| 820 | if (requeue) |
| 821 | aio_queue_work(ctx); |
| 822 | } |
| 823 | |
| 824 | /* |
| 825 | * just like aio_run_iocbs, but keeps running them until |
| 826 | * the list stays empty |
| 827 | */ |
| 828 | static inline void aio_run_all_iocbs(struct kioctx *ctx) |
| 829 | { |
| 830 | spin_lock_irq(&ctx->ctx_lock); |
| 831 | while (__aio_run_iocbs(ctx)) |
| 832 | ; |
| 833 | spin_unlock_irq(&ctx->ctx_lock); |
| 834 | } |
| 835 | |
| 836 | /* |
| 837 | * aio_kick_handler: |
| 838 | * Work queue handler triggered to process pending |
| 839 | * retries on an ioctx. Takes on the aio issuer's |
| 840 | * mm context before running the iocbs, so that |
| 841 | * copy_xxx_user operates on the issuer's address |
| 842 | * space. |
| 843 | * Run on aiod's context. |
| 844 | */ |
| 845 | static void aio_kick_handler(void *data) |
| 846 | { |
| 847 | struct kioctx *ctx = data; |
| 848 | mm_segment_t oldfs = get_fs(); |
| 849 | int requeue; |
| 850 | |
| 851 | set_fs(USER_DS); |
| 852 | use_mm(ctx->mm); |
| 853 | spin_lock_irq(&ctx->ctx_lock); |
| 854 | requeue =__aio_run_iocbs(ctx); |
| 855 | unuse_mm(ctx->mm); |
| 856 | spin_unlock_irq(&ctx->ctx_lock); |
| 857 | set_fs(oldfs); |
| 858 | /* |
| 859 | * we're in a worker thread already, don't use queue_delayed_work, |
| 860 | */ |
| 861 | if (requeue) |
| 862 | queue_work(aio_wq, &ctx->wq); |
| 863 | } |
| 864 | |
| 865 | |
| 866 | /* |
| 867 | * Called by kick_iocb to queue the kiocb for retry |
| 868 | * and if required activate the aio work queue to process |
| 869 | * it |
| 870 | */ |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 871 | static void try_queue_kicked_iocb(struct kiocb *iocb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 872 | { |
| 873 | struct kioctx *ctx = iocb->ki_ctx; |
| 874 | unsigned long flags; |
| 875 | int run = 0; |
| 876 | |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 877 | /* We're supposed to be the only path putting the iocb back on the run |
| 878 | * list. If we find that the iocb is *back* on a wait queue already |
| 879 | * than retry has happened before we could queue the iocb. This also |
| 880 | * means that the retry could have completed and freed our iocb, no |
| 881 | * good. */ |
| 882 | BUG_ON((!list_empty(&iocb->ki_wait.task_list))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | |
| 884 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 885 | /* set this inside the lock so that we can't race with aio_run_iocb() |
| 886 | * testing it and putting the iocb on the run list under the lock */ |
| 887 | if (!kiocbTryKick(iocb)) |
| 888 | run = __queue_kicked_iocb(iocb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 889 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
Ken Chen | 644d3a0 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 890 | if (run) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 891 | aio_queue_work(ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | } |
| 893 | |
| 894 | /* |
| 895 | * kick_iocb: |
| 896 | * Called typically from a wait queue callback context |
| 897 | * (aio_wake_function) to trigger a retry of the iocb. |
| 898 | * The retry is usually executed by aio workqueue |
| 899 | * threads (See aio_kick_handler). |
| 900 | */ |
| 901 | void fastcall kick_iocb(struct kiocb *iocb) |
| 902 | { |
| 903 | /* sync iocbs are easy: they can only ever be executing from a |
| 904 | * single context. */ |
| 905 | if (is_sync_kiocb(iocb)) { |
| 906 | kiocbSetKicked(iocb); |
| 907 | wake_up_process(iocb->ki_obj.tsk); |
| 908 | return; |
| 909 | } |
| 910 | |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 911 | try_queue_kicked_iocb(iocb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | } |
| 913 | EXPORT_SYMBOL(kick_iocb); |
| 914 | |
| 915 | /* aio_complete |
| 916 | * Called when the io request on the given iocb is complete. |
| 917 | * Returns true if this is the last user of the request. The |
| 918 | * only other user of the request can be the cancellation code. |
| 919 | */ |
| 920 | int fastcall aio_complete(struct kiocb *iocb, long res, long res2) |
| 921 | { |
| 922 | struct kioctx *ctx = iocb->ki_ctx; |
| 923 | struct aio_ring_info *info; |
| 924 | struct aio_ring *ring; |
| 925 | struct io_event *event; |
| 926 | unsigned long flags; |
| 927 | unsigned long tail; |
| 928 | int ret; |
| 929 | |
| 930 | /* Special case handling for sync iocbs: events go directly |
| 931 | * into the iocb for fast handling. Note that this will not |
| 932 | * work if we allow sync kiocbs to be cancelled. in which |
| 933 | * case the usage count checks will have to move under ctx_lock |
| 934 | * for all cases. |
| 935 | */ |
| 936 | if (is_sync_kiocb(iocb)) { |
| 937 | int ret; |
| 938 | |
| 939 | iocb->ki_user_data = res; |
| 940 | if (iocb->ki_users == 1) { |
| 941 | iocb->ki_users = 0; |
| 942 | ret = 1; |
| 943 | } else { |
| 944 | spin_lock_irq(&ctx->ctx_lock); |
| 945 | iocb->ki_users--; |
| 946 | ret = (0 == iocb->ki_users); |
| 947 | spin_unlock_irq(&ctx->ctx_lock); |
| 948 | } |
| 949 | /* sync iocbs put the task here for us */ |
| 950 | wake_up_process(iocb->ki_obj.tsk); |
| 951 | return ret; |
| 952 | } |
| 953 | |
| 954 | info = &ctx->ring_info; |
| 955 | |
| 956 | /* add a completion event to the ring buffer. |
| 957 | * must be done holding ctx->ctx_lock to prevent |
| 958 | * other code from messing with the tail |
| 959 | * pointer since we might be called from irq |
| 960 | * context. |
| 961 | */ |
| 962 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
| 963 | |
| 964 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
| 965 | list_del_init(&iocb->ki_run_list); |
| 966 | |
| 967 | /* |
| 968 | * cancelled requests don't get events, userland was given one |
| 969 | * when the event got cancelled. |
| 970 | */ |
| 971 | if (kiocbIsCancelled(iocb)) |
| 972 | goto put_rq; |
| 973 | |
| 974 | ring = kmap_atomic(info->ring_pages[0], KM_IRQ1); |
| 975 | |
| 976 | tail = info->tail; |
| 977 | event = aio_ring_event(info, tail, KM_IRQ0); |
Ken Chen | 4bf69b2 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 978 | if (++tail >= info->nr) |
| 979 | tail = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 980 | |
| 981 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
| 982 | event->data = iocb->ki_user_data; |
| 983 | event->res = res; |
| 984 | event->res2 = res2; |
| 985 | |
| 986 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
| 987 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
| 988 | res, res2); |
| 989 | |
| 990 | /* after flagging the request as done, we |
| 991 | * must never even look at it again |
| 992 | */ |
| 993 | smp_wmb(); /* make event visible before updating tail */ |
| 994 | |
| 995 | info->tail = tail; |
| 996 | ring->tail = tail; |
| 997 | |
| 998 | put_aio_ring_event(event, KM_IRQ0); |
| 999 | kunmap_atomic(ring, KM_IRQ1); |
| 1000 | |
| 1001 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); |
| 1002 | |
Ken Chen | 644d3a0 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 1003 | pr_debug("%ld retries: %d of %d\n", iocb->ki_retried, |
| 1004 | iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1005 | put_rq: |
| 1006 | /* everything turned out well, dispose of the aiocb. */ |
| 1007 | ret = __aio_put_req(ctx, iocb); |
| 1008 | |
| 1009 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
| 1010 | |
| 1011 | if (waitqueue_active(&ctx->wait)) |
| 1012 | wake_up(&ctx->wait); |
| 1013 | |
| 1014 | if (ret) |
| 1015 | put_ioctx(ctx); |
| 1016 | |
| 1017 | return ret; |
| 1018 | } |
| 1019 | |
| 1020 | /* aio_read_evt |
| 1021 | * Pull an event off of the ioctx's event ring. Returns the number of |
| 1022 | * events fetched (0 or 1 ;-) |
| 1023 | * FIXME: make this use cmpxchg. |
| 1024 | * TODO: make the ringbuffer user mmap()able (requires FIXME). |
| 1025 | */ |
| 1026 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
| 1027 | { |
| 1028 | struct aio_ring_info *info = &ioctx->ring_info; |
| 1029 | struct aio_ring *ring; |
| 1030 | unsigned long head; |
| 1031 | int ret = 0; |
| 1032 | |
| 1033 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
| 1034 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
| 1035 | (unsigned long)ring->head, (unsigned long)ring->tail, |
| 1036 | (unsigned long)ring->nr); |
| 1037 | |
| 1038 | if (ring->head == ring->tail) |
| 1039 | goto out; |
| 1040 | |
| 1041 | spin_lock(&info->ring_lock); |
| 1042 | |
| 1043 | head = ring->head % info->nr; |
| 1044 | if (head != ring->tail) { |
| 1045 | struct io_event *evp = aio_ring_event(info, head, KM_USER1); |
| 1046 | *ent = *evp; |
| 1047 | head = (head + 1) % info->nr; |
| 1048 | smp_mb(); /* finish reading the event before updatng the head */ |
| 1049 | ring->head = head; |
| 1050 | ret = 1; |
| 1051 | put_aio_ring_event(evp, KM_USER1); |
| 1052 | } |
| 1053 | spin_unlock(&info->ring_lock); |
| 1054 | |
| 1055 | out: |
| 1056 | kunmap_atomic(ring, KM_USER0); |
| 1057 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
| 1058 | (unsigned long)ring->head, (unsigned long)ring->tail); |
| 1059 | return ret; |
| 1060 | } |
| 1061 | |
| 1062 | struct aio_timeout { |
| 1063 | struct timer_list timer; |
| 1064 | int timed_out; |
| 1065 | struct task_struct *p; |
| 1066 | }; |
| 1067 | |
| 1068 | static void timeout_func(unsigned long data) |
| 1069 | { |
| 1070 | struct aio_timeout *to = (struct aio_timeout *)data; |
| 1071 | |
| 1072 | to->timed_out = 1; |
| 1073 | wake_up_process(to->p); |
| 1074 | } |
| 1075 | |
| 1076 | static inline void init_timeout(struct aio_timeout *to) |
| 1077 | { |
| 1078 | init_timer(&to->timer); |
| 1079 | to->timer.data = (unsigned long)to; |
| 1080 | to->timer.function = timeout_func; |
| 1081 | to->timed_out = 0; |
| 1082 | to->p = current; |
| 1083 | } |
| 1084 | |
| 1085 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
| 1086 | const struct timespec *ts) |
| 1087 | { |
| 1088 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
| 1089 | if (time_after(to->timer.expires, jiffies)) |
| 1090 | add_timer(&to->timer); |
| 1091 | else |
| 1092 | to->timed_out = 1; |
| 1093 | } |
| 1094 | |
| 1095 | static inline void clear_timeout(struct aio_timeout *to) |
| 1096 | { |
| 1097 | del_singleshot_timer_sync(&to->timer); |
| 1098 | } |
| 1099 | |
| 1100 | static int read_events(struct kioctx *ctx, |
| 1101 | long min_nr, long nr, |
| 1102 | struct io_event __user *event, |
| 1103 | struct timespec __user *timeout) |
| 1104 | { |
| 1105 | long start_jiffies = jiffies; |
| 1106 | struct task_struct *tsk = current; |
| 1107 | DECLARE_WAITQUEUE(wait, tsk); |
| 1108 | int ret; |
| 1109 | int i = 0; |
| 1110 | struct io_event ent; |
| 1111 | struct aio_timeout to; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | int retry = 0; |
| 1113 | |
| 1114 | /* needed to zero any padding within an entry (there shouldn't be |
| 1115 | * any, but C is fun! |
| 1116 | */ |
| 1117 | memset(&ent, 0, sizeof(ent)); |
| 1118 | retry: |
| 1119 | ret = 0; |
| 1120 | while (likely(i < nr)) { |
| 1121 | ret = aio_read_evt(ctx, &ent); |
| 1122 | if (unlikely(ret <= 0)) |
| 1123 | break; |
| 1124 | |
| 1125 | dprintk("read event: %Lx %Lx %Lx %Lx\n", |
| 1126 | ent.data, ent.obj, ent.res, ent.res2); |
| 1127 | |
| 1128 | /* Could we split the check in two? */ |
| 1129 | ret = -EFAULT; |
| 1130 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| 1131 | dprintk("aio: lost an event due to EFAULT.\n"); |
| 1132 | break; |
| 1133 | } |
| 1134 | ret = 0; |
| 1135 | |
| 1136 | /* Good, event copied to userland, update counts. */ |
| 1137 | event ++; |
| 1138 | i ++; |
| 1139 | } |
| 1140 | |
| 1141 | if (min_nr <= i) |
| 1142 | return i; |
| 1143 | if (ret) |
| 1144 | return ret; |
| 1145 | |
| 1146 | /* End fast path */ |
| 1147 | |
| 1148 | /* racey check, but it gets redone */ |
| 1149 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
| 1150 | retry = 1; |
| 1151 | aio_run_all_iocbs(ctx); |
| 1152 | goto retry; |
| 1153 | } |
| 1154 | |
| 1155 | init_timeout(&to); |
| 1156 | if (timeout) { |
| 1157 | struct timespec ts; |
| 1158 | ret = -EFAULT; |
| 1159 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
| 1160 | goto out; |
| 1161 | |
| 1162 | set_timeout(start_jiffies, &to, &ts); |
| 1163 | } |
| 1164 | |
| 1165 | while (likely(i < nr)) { |
| 1166 | add_wait_queue_exclusive(&ctx->wait, &wait); |
| 1167 | do { |
| 1168 | set_task_state(tsk, TASK_INTERRUPTIBLE); |
| 1169 | ret = aio_read_evt(ctx, &ent); |
| 1170 | if (ret) |
| 1171 | break; |
| 1172 | if (min_nr <= i) |
| 1173 | break; |
| 1174 | ret = 0; |
| 1175 | if (to.timed_out) /* Only check after read evt */ |
| 1176 | break; |
| 1177 | schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | if (signal_pending(tsk)) { |
| 1179 | ret = -EINTR; |
| 1180 | break; |
| 1181 | } |
| 1182 | /*ret = aio_read_evt(ctx, &ent);*/ |
| 1183 | } while (1) ; |
| 1184 | |
| 1185 | set_task_state(tsk, TASK_RUNNING); |
| 1186 | remove_wait_queue(&ctx->wait, &wait); |
| 1187 | |
| 1188 | if (unlikely(ret <= 0)) |
| 1189 | break; |
| 1190 | |
| 1191 | ret = -EFAULT; |
| 1192 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| 1193 | dprintk("aio: lost an event due to EFAULT.\n"); |
| 1194 | break; |
| 1195 | } |
| 1196 | |
| 1197 | /* Good, event copied to userland, update counts. */ |
| 1198 | event ++; |
| 1199 | i ++; |
| 1200 | } |
| 1201 | |
| 1202 | if (timeout) |
| 1203 | clear_timeout(&to); |
| 1204 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | return i ? i : ret; |
| 1206 | } |
| 1207 | |
| 1208 | /* Take an ioctx and remove it from the list of ioctx's. Protects |
| 1209 | * against races with itself via ->dead. |
| 1210 | */ |
| 1211 | static void io_destroy(struct kioctx *ioctx) |
| 1212 | { |
| 1213 | struct mm_struct *mm = current->mm; |
| 1214 | struct kioctx **tmp; |
| 1215 | int was_dead; |
| 1216 | |
| 1217 | /* delete the entry from the list is someone else hasn't already */ |
| 1218 | write_lock(&mm->ioctx_list_lock); |
| 1219 | was_dead = ioctx->dead; |
| 1220 | ioctx->dead = 1; |
| 1221 | for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx; |
| 1222 | tmp = &(*tmp)->next) |
| 1223 | ; |
| 1224 | if (*tmp) |
| 1225 | *tmp = ioctx->next; |
| 1226 | write_unlock(&mm->ioctx_list_lock); |
| 1227 | |
| 1228 | dprintk("aio_release(%p)\n", ioctx); |
| 1229 | if (likely(!was_dead)) |
| 1230 | put_ioctx(ioctx); /* twice for the list */ |
| 1231 | |
| 1232 | aio_cancel_all(ioctx); |
| 1233 | wait_for_all_aios(ioctx); |
| 1234 | put_ioctx(ioctx); /* once for the lookup */ |
| 1235 | } |
| 1236 | |
| 1237 | /* sys_io_setup: |
| 1238 | * Create an aio_context capable of receiving at least nr_events. |
| 1239 | * ctxp must not point to an aio_context that already exists, and |
| 1240 | * must be initialized to 0 prior to the call. On successful |
| 1241 | * creation of the aio_context, *ctxp is filled in with the resulting |
| 1242 | * handle. May fail with -EINVAL if *ctxp is not initialized, |
| 1243 | * if the specified nr_events exceeds internal limits. May fail |
| 1244 | * with -EAGAIN if the specified nr_events exceeds the user's limit |
| 1245 | * of available events. May fail with -ENOMEM if insufficient kernel |
| 1246 | * resources are available. May fail with -EFAULT if an invalid |
| 1247 | * pointer is passed for ctxp. Will fail with -ENOSYS if not |
| 1248 | * implemented. |
| 1249 | */ |
| 1250 | asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp) |
| 1251 | { |
| 1252 | struct kioctx *ioctx = NULL; |
| 1253 | unsigned long ctx; |
| 1254 | long ret; |
| 1255 | |
| 1256 | ret = get_user(ctx, ctxp); |
| 1257 | if (unlikely(ret)) |
| 1258 | goto out; |
| 1259 | |
| 1260 | ret = -EINVAL; |
| 1261 | if (unlikely(ctx || (int)nr_events <= 0)) { |
| 1262 | pr_debug("EINVAL: io_setup: ctx or nr_events > max\n"); |
| 1263 | goto out; |
| 1264 | } |
| 1265 | |
| 1266 | ioctx = ioctx_alloc(nr_events); |
| 1267 | ret = PTR_ERR(ioctx); |
| 1268 | if (!IS_ERR(ioctx)) { |
| 1269 | ret = put_user(ioctx->user_id, ctxp); |
| 1270 | if (!ret) |
| 1271 | return 0; |
| 1272 | |
| 1273 | get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ |
| 1274 | io_destroy(ioctx); |
| 1275 | } |
| 1276 | |
| 1277 | out: |
| 1278 | return ret; |
| 1279 | } |
| 1280 | |
| 1281 | /* sys_io_destroy: |
| 1282 | * Destroy the aio_context specified. May cancel any outstanding |
| 1283 | * AIOs and block on completion. Will fail with -ENOSYS if not |
| 1284 | * implemented. May fail with -EFAULT if the context pointed to |
| 1285 | * is invalid. |
| 1286 | */ |
| 1287 | asmlinkage long sys_io_destroy(aio_context_t ctx) |
| 1288 | { |
| 1289 | struct kioctx *ioctx = lookup_ioctx(ctx); |
| 1290 | if (likely(NULL != ioctx)) { |
| 1291 | io_destroy(ioctx); |
| 1292 | return 0; |
| 1293 | } |
| 1294 | pr_debug("EINVAL: io_destroy: invalid context id\n"); |
| 1295 | return -EINVAL; |
| 1296 | } |
| 1297 | |
| 1298 | /* |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1299 | * aio_p{read,write} are the default ki_retry methods for |
| 1300 | * IO_CMD_P{READ,WRITE}. They maintains kiocb retry state around potentially |
| 1301 | * multiple calls to f_op->aio_read(). They loop around partial progress |
| 1302 | * instead of returning -EIOCBRETRY because they don't have the means to call |
| 1303 | * kick_iocb(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1304 | */ |
| 1305 | static ssize_t aio_pread(struct kiocb *iocb) |
| 1306 | { |
| 1307 | struct file *file = iocb->ki_filp; |
| 1308 | struct address_space *mapping = file->f_mapping; |
| 1309 | struct inode *inode = mapping->host; |
| 1310 | ssize_t ret = 0; |
| 1311 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1312 | do { |
| 1313 | ret = file->f_op->aio_read(iocb, iocb->ki_buf, |
| 1314 | iocb->ki_left, iocb->ki_pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1315 | /* |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1316 | * Can't just depend on iocb->ki_left to determine |
| 1317 | * whether we are done. This may have been a short read. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1318 | */ |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1319 | if (ret > 0) { |
| 1320 | iocb->ki_buf += ret; |
| 1321 | iocb->ki_left -= ret; |
| 1322 | } |
| 1323 | |
| 1324 | /* |
| 1325 | * For pipes and sockets we return once we have some data; for |
| 1326 | * regular files we retry till we complete the entire read or |
| 1327 | * find that we can't read any more data (e.g short reads). |
| 1328 | */ |
Zach Brown | 353fb07 | 2005-09-30 11:58:56 -0700 | [diff] [blame] | 1329 | } while (ret > 0 && iocb->ki_left > 0 && |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1330 | !S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | |
| 1332 | /* This means we must have transferred all that we could */ |
| 1333 | /* No need to retry anymore */ |
| 1334 | if ((ret == 0) || (iocb->ki_left == 0)) |
| 1335 | ret = iocb->ki_nbytes - iocb->ki_left; |
| 1336 | |
| 1337 | return ret; |
| 1338 | } |
| 1339 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1340 | /* see aio_pread() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | static ssize_t aio_pwrite(struct kiocb *iocb) |
| 1342 | { |
| 1343 | struct file *file = iocb->ki_filp; |
| 1344 | ssize_t ret = 0; |
| 1345 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1346 | do { |
| 1347 | ret = file->f_op->aio_write(iocb, iocb->ki_buf, |
| 1348 | iocb->ki_left, iocb->ki_pos); |
| 1349 | if (ret > 0) { |
| 1350 | iocb->ki_buf += ret; |
| 1351 | iocb->ki_left -= ret; |
| 1352 | } |
Zach Brown | 353fb07 | 2005-09-30 11:58:56 -0700 | [diff] [blame] | 1353 | } while (ret > 0 && iocb->ki_left > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1354 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1355 | if ((ret == 0) || (iocb->ki_left == 0)) |
| 1356 | ret = iocb->ki_nbytes - iocb->ki_left; |
| 1357 | |
| 1358 | return ret; |
| 1359 | } |
| 1360 | |
| 1361 | static ssize_t aio_fdsync(struct kiocb *iocb) |
| 1362 | { |
| 1363 | struct file *file = iocb->ki_filp; |
| 1364 | ssize_t ret = -EINVAL; |
| 1365 | |
| 1366 | if (file->f_op->aio_fsync) |
| 1367 | ret = file->f_op->aio_fsync(iocb, 1); |
| 1368 | return ret; |
| 1369 | } |
| 1370 | |
| 1371 | static ssize_t aio_fsync(struct kiocb *iocb) |
| 1372 | { |
| 1373 | struct file *file = iocb->ki_filp; |
| 1374 | ssize_t ret = -EINVAL; |
| 1375 | |
| 1376 | if (file->f_op->aio_fsync) |
| 1377 | ret = file->f_op->aio_fsync(iocb, 0); |
| 1378 | return ret; |
| 1379 | } |
| 1380 | |
| 1381 | /* |
| 1382 | * aio_setup_iocb: |
| 1383 | * Performs the initial checks and aio retry method |
| 1384 | * setup for the kiocb at the time of io submission. |
| 1385 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1386 | static ssize_t aio_setup_iocb(struct kiocb *kiocb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1387 | { |
| 1388 | struct file *file = kiocb->ki_filp; |
| 1389 | ssize_t ret = 0; |
| 1390 | |
| 1391 | switch (kiocb->ki_opcode) { |
| 1392 | case IOCB_CMD_PREAD: |
| 1393 | ret = -EBADF; |
| 1394 | if (unlikely(!(file->f_mode & FMODE_READ))) |
| 1395 | break; |
| 1396 | ret = -EFAULT; |
| 1397 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
| 1398 | kiocb->ki_left))) |
| 1399 | break; |
| 1400 | ret = -EINVAL; |
| 1401 | if (file->f_op->aio_read) |
| 1402 | kiocb->ki_retry = aio_pread; |
| 1403 | break; |
| 1404 | case IOCB_CMD_PWRITE: |
| 1405 | ret = -EBADF; |
| 1406 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| 1407 | break; |
| 1408 | ret = -EFAULT; |
| 1409 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
| 1410 | kiocb->ki_left))) |
| 1411 | break; |
| 1412 | ret = -EINVAL; |
| 1413 | if (file->f_op->aio_write) |
| 1414 | kiocb->ki_retry = aio_pwrite; |
| 1415 | break; |
| 1416 | case IOCB_CMD_FDSYNC: |
| 1417 | ret = -EINVAL; |
| 1418 | if (file->f_op->aio_fsync) |
| 1419 | kiocb->ki_retry = aio_fdsync; |
| 1420 | break; |
| 1421 | case IOCB_CMD_FSYNC: |
| 1422 | ret = -EINVAL; |
| 1423 | if (file->f_op->aio_fsync) |
| 1424 | kiocb->ki_retry = aio_fsync; |
| 1425 | break; |
| 1426 | default: |
| 1427 | dprintk("EINVAL: io_submit: no operation provided\n"); |
| 1428 | ret = -EINVAL; |
| 1429 | } |
| 1430 | |
| 1431 | if (!kiocb->ki_retry) |
| 1432 | return ret; |
| 1433 | |
| 1434 | return 0; |
| 1435 | } |
| 1436 | |
| 1437 | /* |
| 1438 | * aio_wake_function: |
| 1439 | * wait queue callback function for aio notification, |
| 1440 | * Simply triggers a retry of the operation via kick_iocb. |
| 1441 | * |
| 1442 | * This callback is specified in the wait queue entry in |
| 1443 | * a kiocb (current->io_wait points to this wait queue |
| 1444 | * entry when an aio operation executes; it is used |
| 1445 | * instead of a synchronous wait when an i/o blocking |
| 1446 | * condition is encountered during aio). |
| 1447 | * |
| 1448 | * Note: |
| 1449 | * This routine is executed with the wait queue lock held. |
| 1450 | * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests |
| 1451 | * the ioctx lock inside the wait queue lock. This is safe |
| 1452 | * because this callback isn't used for wait queues which |
| 1453 | * are nested inside ioctx lock (i.e. ctx->wait) |
| 1454 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1455 | static int aio_wake_function(wait_queue_t *wait, unsigned mode, |
| 1456 | int sync, void *key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1457 | { |
| 1458 | struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait); |
| 1459 | |
| 1460 | list_del_init(&wait->task_list); |
| 1461 | kick_iocb(iocb); |
| 1462 | return 1; |
| 1463 | } |
| 1464 | |
| 1465 | int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
| 1466 | struct iocb *iocb) |
| 1467 | { |
| 1468 | struct kiocb *req; |
| 1469 | struct file *file; |
| 1470 | ssize_t ret; |
| 1471 | |
| 1472 | /* enforce forwards compatibility on users */ |
| 1473 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2 || |
| 1474 | iocb->aio_reserved3)) { |
| 1475 | pr_debug("EINVAL: io_submit: reserve field set\n"); |
| 1476 | return -EINVAL; |
| 1477 | } |
| 1478 | |
| 1479 | /* prevent overflows */ |
| 1480 | if (unlikely( |
| 1481 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || |
| 1482 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || |
| 1483 | ((ssize_t)iocb->aio_nbytes < 0) |
| 1484 | )) { |
| 1485 | pr_debug("EINVAL: io_submit: overflow check\n"); |
| 1486 | return -EINVAL; |
| 1487 | } |
| 1488 | |
| 1489 | file = fget(iocb->aio_fildes); |
| 1490 | if (unlikely(!file)) |
| 1491 | return -EBADF; |
| 1492 | |
| 1493 | req = aio_get_req(ctx); /* returns with 2 references to req */ |
| 1494 | if (unlikely(!req)) { |
| 1495 | fput(file); |
| 1496 | return -EAGAIN; |
| 1497 | } |
| 1498 | |
| 1499 | req->ki_filp = file; |
Ken Chen | 212079c | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 1500 | ret = put_user(req->ki_key, &user_iocb->aio_key); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1501 | if (unlikely(ret)) { |
| 1502 | dprintk("EFAULT: aio_key\n"); |
| 1503 | goto out_put_req; |
| 1504 | } |
| 1505 | |
| 1506 | req->ki_obj.user = user_iocb; |
| 1507 | req->ki_user_data = iocb->aio_data; |
| 1508 | req->ki_pos = iocb->aio_offset; |
| 1509 | |
| 1510 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
| 1511 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
| 1512 | req->ki_opcode = iocb->aio_lio_opcode; |
| 1513 | init_waitqueue_func_entry(&req->ki_wait, aio_wake_function); |
| 1514 | INIT_LIST_HEAD(&req->ki_wait.task_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1515 | req->ki_retried = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1516 | |
| 1517 | ret = aio_setup_iocb(req); |
| 1518 | |
| 1519 | if (ret) |
| 1520 | goto out_put_req; |
| 1521 | |
| 1522 | spin_lock_irq(&ctx->ctx_lock); |
Benjamin LaHaise | ac0b1bc | 2005-09-09 13:02:09 -0700 | [diff] [blame] | 1523 | aio_run_iocb(req); |
Benjamin LaHaise | ac0b1bc | 2005-09-09 13:02:09 -0700 | [diff] [blame] | 1524 | if (!list_empty(&ctx->run_list)) { |
Ken Chen | 954d3e9 | 2005-05-01 08:59:16 -0700 | [diff] [blame] | 1525 | /* drain the run list */ |
| 1526 | while (__aio_run_iocbs(ctx)) |
| 1527 | ; |
| 1528 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1529 | spin_unlock_irq(&ctx->ctx_lock); |
| 1530 | aio_put_req(req); /* drop extra ref to req */ |
| 1531 | return 0; |
| 1532 | |
| 1533 | out_put_req: |
| 1534 | aio_put_req(req); /* drop extra ref to req */ |
| 1535 | aio_put_req(req); /* drop i/o ref to req */ |
| 1536 | return ret; |
| 1537 | } |
| 1538 | |
| 1539 | /* sys_io_submit: |
| 1540 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns |
| 1541 | * the number of iocbs queued. May return -EINVAL if the aio_context |
| 1542 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at |
| 1543 | * *iocbpp[0] is not properly initialized, if the operation specified |
| 1544 | * is invalid for the file descriptor in the iocb. May fail with |
| 1545 | * -EFAULT if any of the data structures point to invalid data. May |
| 1546 | * fail with -EBADF if the file descriptor specified in the first |
| 1547 | * iocb is invalid. May fail with -EAGAIN if insufficient resources |
| 1548 | * are available to queue any iocbs. Will return 0 if nr is 0. Will |
| 1549 | * fail with -ENOSYS if not implemented. |
| 1550 | */ |
| 1551 | asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr, |
| 1552 | struct iocb __user * __user *iocbpp) |
| 1553 | { |
| 1554 | struct kioctx *ctx; |
| 1555 | long ret = 0; |
| 1556 | int i; |
| 1557 | |
| 1558 | if (unlikely(nr < 0)) |
| 1559 | return -EINVAL; |
| 1560 | |
| 1561 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
| 1562 | return -EFAULT; |
| 1563 | |
| 1564 | ctx = lookup_ioctx(ctx_id); |
| 1565 | if (unlikely(!ctx)) { |
| 1566 | pr_debug("EINVAL: io_submit: invalid context id\n"); |
| 1567 | return -EINVAL; |
| 1568 | } |
| 1569 | |
| 1570 | /* |
| 1571 | * AKPM: should this return a partial result if some of the IOs were |
| 1572 | * successfully submitted? |
| 1573 | */ |
| 1574 | for (i=0; i<nr; i++) { |
| 1575 | struct iocb __user *user_iocb; |
| 1576 | struct iocb tmp; |
| 1577 | |
| 1578 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
| 1579 | ret = -EFAULT; |
| 1580 | break; |
| 1581 | } |
| 1582 | |
| 1583 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
| 1584 | ret = -EFAULT; |
| 1585 | break; |
| 1586 | } |
| 1587 | |
| 1588 | ret = io_submit_one(ctx, user_iocb, &tmp); |
| 1589 | if (ret) |
| 1590 | break; |
| 1591 | } |
| 1592 | |
| 1593 | put_ioctx(ctx); |
| 1594 | return i ? i : ret; |
| 1595 | } |
| 1596 | |
| 1597 | /* lookup_kiocb |
| 1598 | * Finds a given iocb for cancellation. |
| 1599 | * MUST be called with ctx->ctx_lock held. |
| 1600 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1601 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
| 1602 | u32 key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1603 | { |
| 1604 | struct list_head *pos; |
| 1605 | /* TODO: use a hash or array, this sucks. */ |
| 1606 | list_for_each(pos, &ctx->active_reqs) { |
| 1607 | struct kiocb *kiocb = list_kiocb(pos); |
| 1608 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
| 1609 | return kiocb; |
| 1610 | } |
| 1611 | return NULL; |
| 1612 | } |
| 1613 | |
| 1614 | /* sys_io_cancel: |
| 1615 | * Attempts to cancel an iocb previously passed to io_submit. If |
| 1616 | * the operation is successfully cancelled, the resulting event is |
| 1617 | * copied into the memory pointed to by result without being placed |
| 1618 | * into the completion queue and 0 is returned. May fail with |
| 1619 | * -EFAULT if any of the data structures pointed to are invalid. |
| 1620 | * May fail with -EINVAL if aio_context specified by ctx_id is |
| 1621 | * invalid. May fail with -EAGAIN if the iocb specified was not |
| 1622 | * cancelled. Will fail with -ENOSYS if not implemented. |
| 1623 | */ |
| 1624 | asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb, |
| 1625 | struct io_event __user *result) |
| 1626 | { |
| 1627 | int (*cancel)(struct kiocb *iocb, struct io_event *res); |
| 1628 | struct kioctx *ctx; |
| 1629 | struct kiocb *kiocb; |
| 1630 | u32 key; |
| 1631 | int ret; |
| 1632 | |
| 1633 | ret = get_user(key, &iocb->aio_key); |
| 1634 | if (unlikely(ret)) |
| 1635 | return -EFAULT; |
| 1636 | |
| 1637 | ctx = lookup_ioctx(ctx_id); |
| 1638 | if (unlikely(!ctx)) |
| 1639 | return -EINVAL; |
| 1640 | |
| 1641 | spin_lock_irq(&ctx->ctx_lock); |
| 1642 | ret = -EAGAIN; |
| 1643 | kiocb = lookup_kiocb(ctx, iocb, key); |
| 1644 | if (kiocb && kiocb->ki_cancel) { |
| 1645 | cancel = kiocb->ki_cancel; |
| 1646 | kiocb->ki_users ++; |
| 1647 | kiocbSetCancelled(kiocb); |
| 1648 | } else |
| 1649 | cancel = NULL; |
| 1650 | spin_unlock_irq(&ctx->ctx_lock); |
| 1651 | |
| 1652 | if (NULL != cancel) { |
| 1653 | struct io_event tmp; |
| 1654 | pr_debug("calling cancel\n"); |
| 1655 | memset(&tmp, 0, sizeof(tmp)); |
| 1656 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
| 1657 | tmp.data = kiocb->ki_user_data; |
| 1658 | ret = cancel(kiocb, &tmp); |
| 1659 | if (!ret) { |
| 1660 | /* Cancellation succeeded -- copy the result |
| 1661 | * into the user's buffer. |
| 1662 | */ |
| 1663 | if (copy_to_user(result, &tmp, sizeof(tmp))) |
| 1664 | ret = -EFAULT; |
| 1665 | } |
| 1666 | } else |
Wendy Cheng | 8f58202 | 2005-09-09 13:02:08 -0700 | [diff] [blame] | 1667 | ret = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1668 | |
| 1669 | put_ioctx(ctx); |
| 1670 | |
| 1671 | return ret; |
| 1672 | } |
| 1673 | |
| 1674 | /* io_getevents: |
| 1675 | * Attempts to read at least min_nr events and up to nr events from |
| 1676 | * the completion queue for the aio_context specified by ctx_id. May |
| 1677 | * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range, |
| 1678 | * if nr is out of range, if when is out of range. May fail with |
| 1679 | * -EFAULT if any of the memory specified to is invalid. May return |
| 1680 | * 0 or < min_nr if no events are available and the timeout specified |
| 1681 | * by when has elapsed, where when == NULL specifies an infinite |
| 1682 | * timeout. Note that the timeout pointed to by when is relative and |
| 1683 | * will be updated if not NULL and the operation blocks. Will fail |
| 1684 | * with -ENOSYS if not implemented. |
| 1685 | */ |
| 1686 | asmlinkage long sys_io_getevents(aio_context_t ctx_id, |
| 1687 | long min_nr, |
| 1688 | long nr, |
| 1689 | struct io_event __user *events, |
| 1690 | struct timespec __user *timeout) |
| 1691 | { |
| 1692 | struct kioctx *ioctx = lookup_ioctx(ctx_id); |
| 1693 | long ret = -EINVAL; |
| 1694 | |
| 1695 | if (likely(ioctx)) { |
| 1696 | if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0)) |
| 1697 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
| 1698 | put_ioctx(ioctx); |
| 1699 | } |
| 1700 | |
| 1701 | return ret; |
| 1702 | } |
| 1703 | |
| 1704 | __initcall(aio_setup); |
| 1705 | |
| 1706 | EXPORT_SYMBOL(aio_complete); |
| 1707 | EXPORT_SYMBOL(aio_put_req); |
| 1708 | EXPORT_SYMBOL(wait_on_sync_kiocb); |