| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 4 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics |
| 5 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| 6 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> |
| 7 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
| 8 | * - July2000 |
| 9 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
| 10 | */ |
| 11 | |
| 12 | /* |
| 13 | * This handles all read/write requests to block devices |
| 14 | */ |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/bio.h> |
| 18 | #include <linux/blkdev.h> |
| 19 | #include <linux/blk-pm.h> |
| 20 | #include <linux/blk-integrity.h> |
| 21 | #include <linux/highmem.h> |
| 22 | #include <linux/mm.h> |
| 23 | #include <linux/pagemap.h> |
| 24 | #include <linux/kernel_stat.h> |
| 25 | #include <linux/string.h> |
| 26 | #include <linux/init.h> |
| 27 | #include <linux/completion.h> |
| 28 | #include <linux/slab.h> |
| 29 | #include <linux/swap.h> |
| 30 | #include <linux/writeback.h> |
| 31 | #include <linux/task_io_accounting_ops.h> |
| 32 | #include <linux/fault-inject.h> |
| 33 | #include <linux/list_sort.h> |
| 34 | #include <linux/delay.h> |
| 35 | #include <linux/ratelimit.h> |
| 36 | #include <linux/pm_runtime.h> |
| 37 | #include <linux/t10-pi.h> |
| 38 | #include <linux/debugfs.h> |
| 39 | #include <linux/bpf.h> |
| 40 | #include <linux/part_stat.h> |
| 41 | #include <linux/sched/sysctl.h> |
| 42 | #include <linux/blk-crypto.h> |
| 43 | |
| 44 | #define CREATE_TRACE_POINTS |
| 45 | #include <trace/events/block.h> |
| 46 | |
| 47 | #include "blk.h" |
| 48 | #include "blk-mq-sched.h" |
| 49 | #include "blk-pm.h" |
| 50 | #include "blk-cgroup.h" |
| 51 | #include "blk-throttle.h" |
| 52 | |
| 53 | struct dentry *blk_debugfs_root; |
| 54 | |
| 55 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
| 56 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
| 57 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
| 58 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
| 59 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
| 60 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert); |
| 61 | |
| 62 | static DEFINE_IDA(blk_queue_ida); |
| 63 | |
| 64 | /* |
| 65 | * For queue allocation |
| 66 | */ |
| 67 | static struct kmem_cache *blk_requestq_cachep; |
| 68 | |
| 69 | /* |
| 70 | * Controlling structure to kblockd |
| 71 | */ |
| 72 | static struct workqueue_struct *kblockd_workqueue; |
| 73 | |
| 74 | /** |
| 75 | * blk_queue_flag_set - atomically set a queue flag |
| 76 | * @flag: flag to be set |
| 77 | * @q: request queue |
| 78 | */ |
| 79 | void blk_queue_flag_set(unsigned int flag, struct request_queue *q) |
| 80 | { |
| 81 | set_bit(flag, &q->queue_flags); |
| 82 | } |
| 83 | EXPORT_SYMBOL(blk_queue_flag_set); |
| 84 | |
| 85 | /** |
| 86 | * blk_queue_flag_clear - atomically clear a queue flag |
| 87 | * @flag: flag to be cleared |
| 88 | * @q: request queue |
| 89 | */ |
| 90 | void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) |
| 91 | { |
| 92 | clear_bit(flag, &q->queue_flags); |
| 93 | } |
| 94 | EXPORT_SYMBOL(blk_queue_flag_clear); |
| 95 | |
| 96 | /** |
| 97 | * blk_queue_flag_test_and_set - atomically test and set a queue flag |
| 98 | * @flag: flag to be set |
| 99 | * @q: request queue |
| 100 | * |
| 101 | * Returns the previous value of @flag - 0 if the flag was not set and 1 if |
| 102 | * the flag was already set. |
| 103 | */ |
| 104 | bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) |
| 105 | { |
| 106 | return test_and_set_bit(flag, &q->queue_flags); |
| 107 | } |
| 108 | EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); |
| 109 | |
| 110 | #define REQ_OP_NAME(name) [REQ_OP_##name] = #name |
| 111 | static const char *const blk_op_name[] = { |
| 112 | REQ_OP_NAME(READ), |
| 113 | REQ_OP_NAME(WRITE), |
| 114 | REQ_OP_NAME(FLUSH), |
| 115 | REQ_OP_NAME(DISCARD), |
| 116 | REQ_OP_NAME(SECURE_ERASE), |
| 117 | REQ_OP_NAME(ZONE_RESET), |
| 118 | REQ_OP_NAME(ZONE_RESET_ALL), |
| 119 | REQ_OP_NAME(ZONE_OPEN), |
| 120 | REQ_OP_NAME(ZONE_CLOSE), |
| 121 | REQ_OP_NAME(ZONE_FINISH), |
| 122 | REQ_OP_NAME(ZONE_APPEND), |
| 123 | REQ_OP_NAME(WRITE_ZEROES), |
| 124 | REQ_OP_NAME(DRV_IN), |
| 125 | REQ_OP_NAME(DRV_OUT), |
| 126 | }; |
| 127 | #undef REQ_OP_NAME |
| 128 | |
| 129 | /** |
| 130 | * blk_op_str - Return string XXX in the REQ_OP_XXX. |
| 131 | * @op: REQ_OP_XXX. |
| 132 | * |
| 133 | * Description: Centralize block layer function to convert REQ_OP_XXX into |
| 134 | * string format. Useful in the debugging and tracing bio or request. For |
| 135 | * invalid REQ_OP_XXX it returns string "UNKNOWN". |
| 136 | */ |
| 137 | inline const char *blk_op_str(enum req_op op) |
| 138 | { |
| 139 | const char *op_str = "UNKNOWN"; |
| 140 | |
| 141 | if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op]) |
| 142 | op_str = blk_op_name[op]; |
| 143 | |
| 144 | return op_str; |
| 145 | } |
| 146 | EXPORT_SYMBOL_GPL(blk_op_str); |
| 147 | |
| 148 | static const struct { |
| 149 | int errno; |
| 150 | const char *name; |
| 151 | } blk_errors[] = { |
| 152 | [BLK_STS_OK] = { 0, "" }, |
| 153 | [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, |
| 154 | [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, |
| 155 | [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, |
| 156 | [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, |
| 157 | [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, |
| 158 | [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, |
| 159 | [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, |
| 160 | [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, |
| 161 | [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, |
| 162 | [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, |
| 163 | [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, |
| 164 | [BLK_STS_OFFLINE] = { -ENODEV, "device offline" }, |
| 165 | |
| 166 | /* device mapper special case, should not leak out: */ |
| 167 | [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, |
| 168 | |
| 169 | /* zone device specific errors */ |
| 170 | [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" }, |
| 171 | [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" }, |
| 172 | |
| 173 | /* everything else not covered above: */ |
| 174 | [BLK_STS_IOERR] = { -EIO, "I/O" }, |
| 175 | }; |
| 176 | |
| 177 | blk_status_t errno_to_blk_status(int errno) |
| 178 | { |
| 179 | int i; |
| 180 | |
| 181 | for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { |
| 182 | if (blk_errors[i].errno == errno) |
| 183 | return (__force blk_status_t)i; |
| 184 | } |
| 185 | |
| 186 | return BLK_STS_IOERR; |
| 187 | } |
| 188 | EXPORT_SYMBOL_GPL(errno_to_blk_status); |
| 189 | |
| 190 | int blk_status_to_errno(blk_status_t status) |
| 191 | { |
| 192 | int idx = (__force int)status; |
| 193 | |
| 194 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
| 195 | return -EIO; |
| 196 | return blk_errors[idx].errno; |
| 197 | } |
| 198 | EXPORT_SYMBOL_GPL(blk_status_to_errno); |
| 199 | |
| 200 | const char *blk_status_to_str(blk_status_t status) |
| 201 | { |
| 202 | int idx = (__force int)status; |
| 203 | |
| 204 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
| 205 | return "<null>"; |
| 206 | return blk_errors[idx].name; |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * blk_sync_queue - cancel any pending callbacks on a queue |
| 211 | * @q: the queue |
| 212 | * |
| 213 | * Description: |
| 214 | * The block layer may perform asynchronous callback activity |
| 215 | * on a queue, such as calling the unplug function after a timeout. |
| 216 | * A block device may call blk_sync_queue to ensure that any |
| 217 | * such activity is cancelled, thus allowing it to release resources |
| 218 | * that the callbacks might use. The caller must already have made sure |
| 219 | * that its ->submit_bio will not re-add plugging prior to calling |
| 220 | * this function. |
| 221 | * |
| 222 | * This function does not cancel any asynchronous activity arising |
| 223 | * out of elevator or throttling code. That would require elevator_exit() |
| 224 | * and blkcg_exit_queue() to be called with queue lock initialized. |
| 225 | * |
| 226 | */ |
| 227 | void blk_sync_queue(struct request_queue *q) |
| 228 | { |
| 229 | del_timer_sync(&q->timeout); |
| 230 | cancel_work_sync(&q->timeout_work); |
| 231 | } |
| 232 | EXPORT_SYMBOL(blk_sync_queue); |
| 233 | |
| 234 | /** |
| 235 | * blk_set_pm_only - increment pm_only counter |
| 236 | * @q: request queue pointer |
| 237 | */ |
| 238 | void blk_set_pm_only(struct request_queue *q) |
| 239 | { |
| 240 | atomic_inc(&q->pm_only); |
| 241 | } |
| 242 | EXPORT_SYMBOL_GPL(blk_set_pm_only); |
| 243 | |
| 244 | void blk_clear_pm_only(struct request_queue *q) |
| 245 | { |
| 246 | int pm_only; |
| 247 | |
| 248 | pm_only = atomic_dec_return(&q->pm_only); |
| 249 | WARN_ON_ONCE(pm_only < 0); |
| 250 | if (pm_only == 0) |
| 251 | wake_up_all(&q->mq_freeze_wq); |
| 252 | } |
| 253 | EXPORT_SYMBOL_GPL(blk_clear_pm_only); |
| 254 | |
| 255 | static void blk_free_queue_rcu(struct rcu_head *rcu_head) |
| 256 | { |
| 257 | struct request_queue *q = container_of(rcu_head, |
| 258 | struct request_queue, rcu_head); |
| 259 | |
| 260 | percpu_ref_exit(&q->q_usage_counter); |
| 261 | kmem_cache_free(blk_requestq_cachep, q); |
| 262 | } |
| 263 | |
| 264 | static void blk_free_queue(struct request_queue *q) |
| 265 | { |
| 266 | blk_free_queue_stats(q->stats); |
| 267 | if (queue_is_mq(q)) |
| 268 | blk_mq_release(q); |
| 269 | |
| 270 | ida_free(&blk_queue_ida, q->id); |
| 271 | call_rcu(&q->rcu_head, blk_free_queue_rcu); |
| 272 | } |
| 273 | |
| 274 | /** |
| 275 | * blk_put_queue - decrement the request_queue refcount |
| 276 | * @q: the request_queue structure to decrement the refcount for |
| 277 | * |
| 278 | * Decrements the refcount of the request_queue and free it when the refcount |
| 279 | * reaches 0. |
| 280 | */ |
| 281 | void blk_put_queue(struct request_queue *q) |
| 282 | { |
| 283 | if (refcount_dec_and_test(&q->refs)) |
| 284 | blk_free_queue(q); |
| 285 | } |
| 286 | EXPORT_SYMBOL(blk_put_queue); |
| 287 | |
| 288 | void blk_queue_start_drain(struct request_queue *q) |
| 289 | { |
| 290 | /* |
| 291 | * When queue DYING flag is set, we need to block new req |
| 292 | * entering queue, so we call blk_freeze_queue_start() to |
| 293 | * prevent I/O from crossing blk_queue_enter(). |
| 294 | */ |
| 295 | blk_freeze_queue_start(q); |
| 296 | if (queue_is_mq(q)) |
| 297 | blk_mq_wake_waiters(q); |
| 298 | /* Make blk_queue_enter() reexamine the DYING flag. */ |
| 299 | wake_up_all(&q->mq_freeze_wq); |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * blk_queue_enter() - try to increase q->q_usage_counter |
| 304 | * @q: request queue pointer |
| 305 | * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM |
| 306 | */ |
| 307 | int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) |
| 308 | { |
| 309 | const bool pm = flags & BLK_MQ_REQ_PM; |
| 310 | |
| 311 | while (!blk_try_enter_queue(q, pm)) { |
| 312 | if (flags & BLK_MQ_REQ_NOWAIT) |
| 313 | return -EAGAIN; |
| 314 | |
| 315 | /* |
| 316 | * read pair of barrier in blk_freeze_queue_start(), we need to |
| 317 | * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
| 318 | * reading .mq_freeze_depth or queue dying flag, otherwise the |
| 319 | * following wait may never return if the two reads are |
| 320 | * reordered. |
| 321 | */ |
| 322 | smp_rmb(); |
| 323 | wait_event(q->mq_freeze_wq, |
| 324 | (!q->mq_freeze_depth && |
| 325 | blk_pm_resume_queue(pm, q)) || |
| 326 | blk_queue_dying(q)); |
| 327 | if (blk_queue_dying(q)) |
| 328 | return -ENODEV; |
| 329 | } |
| 330 | |
| 331 | return 0; |
| 332 | } |
| 333 | |
| 334 | int __bio_queue_enter(struct request_queue *q, struct bio *bio) |
| 335 | { |
| 336 | while (!blk_try_enter_queue(q, false)) { |
| 337 | struct gendisk *disk = bio->bi_bdev->bd_disk; |
| 338 | |
| 339 | if (bio->bi_opf & REQ_NOWAIT) { |
| 340 | if (test_bit(GD_DEAD, &disk->state)) |
| 341 | goto dead; |
| 342 | bio_wouldblock_error(bio); |
| 343 | return -EAGAIN; |
| 344 | } |
| 345 | |
| 346 | /* |
| 347 | * read pair of barrier in blk_freeze_queue_start(), we need to |
| 348 | * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
| 349 | * reading .mq_freeze_depth or queue dying flag, otherwise the |
| 350 | * following wait may never return if the two reads are |
| 351 | * reordered. |
| 352 | */ |
| 353 | smp_rmb(); |
| 354 | wait_event(q->mq_freeze_wq, |
| 355 | (!q->mq_freeze_depth && |
| 356 | blk_pm_resume_queue(false, q)) || |
| 357 | test_bit(GD_DEAD, &disk->state)); |
| 358 | if (test_bit(GD_DEAD, &disk->state)) |
| 359 | goto dead; |
| 360 | } |
| 361 | |
| 362 | return 0; |
| 363 | dead: |
| 364 | bio_io_error(bio); |
| 365 | return -ENODEV; |
| 366 | } |
| 367 | |
| 368 | void blk_queue_exit(struct request_queue *q) |
| 369 | { |
| 370 | percpu_ref_put(&q->q_usage_counter); |
| 371 | } |
| 372 | |
| 373 | static void blk_queue_usage_counter_release(struct percpu_ref *ref) |
| 374 | { |
| 375 | struct request_queue *q = |
| 376 | container_of(ref, struct request_queue, q_usage_counter); |
| 377 | |
| 378 | wake_up_all(&q->mq_freeze_wq); |
| 379 | } |
| 380 | |
| 381 | static void blk_rq_timed_out_timer(struct timer_list *t) |
| 382 | { |
| 383 | struct request_queue *q = from_timer(q, t, timeout); |
| 384 | |
| 385 | kblockd_schedule_work(&q->timeout_work); |
| 386 | } |
| 387 | |
| 388 | static void blk_timeout_work(struct work_struct *work) |
| 389 | { |
| 390 | } |
| 391 | |
| 392 | struct request_queue *blk_alloc_queue(int node_id) |
| 393 | { |
| 394 | struct request_queue *q; |
| 395 | |
| 396 | q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO, |
| 397 | node_id); |
| 398 | if (!q) |
| 399 | return NULL; |
| 400 | |
| 401 | q->last_merge = NULL; |
| 402 | |
| 403 | q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL); |
| 404 | if (q->id < 0) |
| 405 | goto fail_q; |
| 406 | |
| 407 | q->stats = blk_alloc_queue_stats(); |
| 408 | if (!q->stats) |
| 409 | goto fail_id; |
| 410 | |
| 411 | q->node = node_id; |
| 412 | |
| 413 | atomic_set(&q->nr_active_requests_shared_tags, 0); |
| 414 | |
| 415 | timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); |
| 416 | INIT_WORK(&q->timeout_work, blk_timeout_work); |
| 417 | INIT_LIST_HEAD(&q->icq_list); |
| 418 | |
| 419 | refcount_set(&q->refs, 1); |
| 420 | mutex_init(&q->debugfs_mutex); |
| 421 | mutex_init(&q->sysfs_lock); |
| 422 | mutex_init(&q->sysfs_dir_lock); |
| 423 | spin_lock_init(&q->queue_lock); |
| 424 | |
| 425 | init_waitqueue_head(&q->mq_freeze_wq); |
| 426 | mutex_init(&q->mq_freeze_lock); |
| 427 | |
| 428 | /* |
| 429 | * Init percpu_ref in atomic mode so that it's faster to shutdown. |
| 430 | * See blk_register_queue() for details. |
| 431 | */ |
| 432 | if (percpu_ref_init(&q->q_usage_counter, |
| 433 | blk_queue_usage_counter_release, |
| 434 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) |
| 435 | goto fail_stats; |
| 436 | |
| 437 | blk_set_default_limits(&q->limits); |
| 438 | q->nr_requests = BLKDEV_DEFAULT_RQ; |
| 439 | |
| 440 | return q; |
| 441 | |
| 442 | fail_stats: |
| 443 | blk_free_queue_stats(q->stats); |
| 444 | fail_id: |
| 445 | ida_free(&blk_queue_ida, q->id); |
| 446 | fail_q: |
| 447 | kmem_cache_free(blk_requestq_cachep, q); |
| 448 | return NULL; |
| 449 | } |
| 450 | |
| 451 | /** |
| 452 | * blk_get_queue - increment the request_queue refcount |
| 453 | * @q: the request_queue structure to increment the refcount for |
| 454 | * |
| 455 | * Increment the refcount of the request_queue kobject. |
| 456 | * |
| 457 | * Context: Any context. |
| 458 | */ |
| 459 | bool blk_get_queue(struct request_queue *q) |
| 460 | { |
| 461 | if (unlikely(blk_queue_dying(q))) |
| 462 | return false; |
| 463 | refcount_inc(&q->refs); |
| 464 | return true; |
| 465 | } |
| 466 | EXPORT_SYMBOL(blk_get_queue); |
| 467 | |
| 468 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
| 469 | |
| 470 | static DECLARE_FAULT_ATTR(fail_make_request); |
| 471 | |
| 472 | static int __init setup_fail_make_request(char *str) |
| 473 | { |
| 474 | return setup_fault_attr(&fail_make_request, str); |
| 475 | } |
| 476 | __setup("fail_make_request=", setup_fail_make_request); |
| 477 | |
| 478 | bool should_fail_request(struct block_device *part, unsigned int bytes) |
| 479 | { |
| 480 | return part->bd_make_it_fail && should_fail(&fail_make_request, bytes); |
| 481 | } |
| 482 | |
| 483 | static int __init fail_make_request_debugfs(void) |
| 484 | { |
| 485 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
| 486 | NULL, &fail_make_request); |
| 487 | |
| 488 | return PTR_ERR_OR_ZERO(dir); |
| 489 | } |
| 490 | |
| 491 | late_initcall(fail_make_request_debugfs); |
| 492 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
| 493 | |
| 494 | static inline void bio_check_ro(struct bio *bio) |
| 495 | { |
| 496 | if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) { |
| 497 | if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) |
| 498 | return; |
| 499 | pr_warn("Trying to write to read-only block-device %pg\n", |
| 500 | bio->bi_bdev); |
| 501 | /* Older lvm-tools actually trigger this */ |
| 502 | } |
| 503 | } |
| 504 | |
| 505 | static noinline int should_fail_bio(struct bio *bio) |
| 506 | { |
| 507 | if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size)) |
| 508 | return -EIO; |
| 509 | return 0; |
| 510 | } |
| 511 | ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); |
| 512 | |
| 513 | /* |
| 514 | * Check whether this bio extends beyond the end of the device or partition. |
| 515 | * This may well happen - the kernel calls bread() without checking the size of |
| 516 | * the device, e.g., when mounting a file system. |
| 517 | */ |
| 518 | static inline int bio_check_eod(struct bio *bio) |
| 519 | { |
| 520 | sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); |
| 521 | unsigned int nr_sectors = bio_sectors(bio); |
| 522 | |
| 523 | if (nr_sectors && maxsector && |
| 524 | (nr_sectors > maxsector || |
| 525 | bio->bi_iter.bi_sector > maxsector - nr_sectors)) { |
| 526 | pr_info_ratelimited("%s: attempt to access beyond end of device\n" |
| 527 | "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n", |
| 528 | current->comm, bio->bi_bdev, bio->bi_opf, |
| 529 | bio->bi_iter.bi_sector, nr_sectors, maxsector); |
| 530 | return -EIO; |
| 531 | } |
| 532 | return 0; |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * Remap block n of partition p to block n+start(p) of the disk. |
| 537 | */ |
| 538 | static int blk_partition_remap(struct bio *bio) |
| 539 | { |
| 540 | struct block_device *p = bio->bi_bdev; |
| 541 | |
| 542 | if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) |
| 543 | return -EIO; |
| 544 | if (bio_sectors(bio)) { |
| 545 | bio->bi_iter.bi_sector += p->bd_start_sect; |
| 546 | trace_block_bio_remap(bio, p->bd_dev, |
| 547 | bio->bi_iter.bi_sector - |
| 548 | p->bd_start_sect); |
| 549 | } |
| 550 | bio_set_flag(bio, BIO_REMAPPED); |
| 551 | return 0; |
| 552 | } |
| 553 | |
| 554 | /* |
| 555 | * Check write append to a zoned block device. |
| 556 | */ |
| 557 | static inline blk_status_t blk_check_zone_append(struct request_queue *q, |
| 558 | struct bio *bio) |
| 559 | { |
| 560 | int nr_sectors = bio_sectors(bio); |
| 561 | |
| 562 | /* Only applicable to zoned block devices */ |
| 563 | if (!bdev_is_zoned(bio->bi_bdev)) |
| 564 | return BLK_STS_NOTSUPP; |
| 565 | |
| 566 | /* The bio sector must point to the start of a sequential zone */ |
| 567 | if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) || |
| 568 | !bio_zone_is_seq(bio)) |
| 569 | return BLK_STS_IOERR; |
| 570 | |
| 571 | /* |
| 572 | * Not allowed to cross zone boundaries. Otherwise, the BIO will be |
| 573 | * split and could result in non-contiguous sectors being written in |
| 574 | * different zones. |
| 575 | */ |
| 576 | if (nr_sectors > q->limits.chunk_sectors) |
| 577 | return BLK_STS_IOERR; |
| 578 | |
| 579 | /* Make sure the BIO is small enough and will not get split */ |
| 580 | if (nr_sectors > q->limits.max_zone_append_sectors) |
| 581 | return BLK_STS_IOERR; |
| 582 | |
| 583 | bio->bi_opf |= REQ_NOMERGE; |
| 584 | |
| 585 | return BLK_STS_OK; |
| 586 | } |
| 587 | |
| 588 | static void __submit_bio(struct bio *bio) |
| 589 | { |
| 590 | if (unlikely(!blk_crypto_bio_prep(&bio))) |
| 591 | return; |
| 592 | |
| 593 | if (!bio->bi_bdev->bd_has_submit_bio) { |
| 594 | blk_mq_submit_bio(bio); |
| 595 | } else if (likely(bio_queue_enter(bio) == 0)) { |
| 596 | struct gendisk *disk = bio->bi_bdev->bd_disk; |
| 597 | |
| 598 | disk->fops->submit_bio(bio); |
| 599 | blk_queue_exit(disk->queue); |
| 600 | } |
| 601 | } |
| 602 | |
| 603 | /* |
| 604 | * The loop in this function may be a bit non-obvious, and so deserves some |
| 605 | * explanation: |
| 606 | * |
| 607 | * - Before entering the loop, bio->bi_next is NULL (as all callers ensure |
| 608 | * that), so we have a list with a single bio. |
| 609 | * - We pretend that we have just taken it off a longer list, so we assign |
| 610 | * bio_list to a pointer to the bio_list_on_stack, thus initialising the |
| 611 | * bio_list of new bios to be added. ->submit_bio() may indeed add some more |
| 612 | * bios through a recursive call to submit_bio_noacct. If it did, we find a |
| 613 | * non-NULL value in bio_list and re-enter the loop from the top. |
| 614 | * - In this case we really did just take the bio of the top of the list (no |
| 615 | * pretending) and so remove it from bio_list, and call into ->submit_bio() |
| 616 | * again. |
| 617 | * |
| 618 | * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. |
| 619 | * bio_list_on_stack[1] contains bios that were submitted before the current |
| 620 | * ->submit_bio, but that haven't been processed yet. |
| 621 | */ |
| 622 | static void __submit_bio_noacct(struct bio *bio) |
| 623 | { |
| 624 | struct bio_list bio_list_on_stack[2]; |
| 625 | |
| 626 | BUG_ON(bio->bi_next); |
| 627 | |
| 628 | bio_list_init(&bio_list_on_stack[0]); |
| 629 | current->bio_list = bio_list_on_stack; |
| 630 | |
| 631 | do { |
| 632 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| 633 | struct bio_list lower, same; |
| 634 | |
| 635 | /* |
| 636 | * Create a fresh bio_list for all subordinate requests. |
| 637 | */ |
| 638 | bio_list_on_stack[1] = bio_list_on_stack[0]; |
| 639 | bio_list_init(&bio_list_on_stack[0]); |
| 640 | |
| 641 | __submit_bio(bio); |
| 642 | |
| 643 | /* |
| 644 | * Sort new bios into those for a lower level and those for the |
| 645 | * same level. |
| 646 | */ |
| 647 | bio_list_init(&lower); |
| 648 | bio_list_init(&same); |
| 649 | while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) |
| 650 | if (q == bdev_get_queue(bio->bi_bdev)) |
| 651 | bio_list_add(&same, bio); |
| 652 | else |
| 653 | bio_list_add(&lower, bio); |
| 654 | |
| 655 | /* |
| 656 | * Now assemble so we handle the lowest level first. |
| 657 | */ |
| 658 | bio_list_merge(&bio_list_on_stack[0], &lower); |
| 659 | bio_list_merge(&bio_list_on_stack[0], &same); |
| 660 | bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); |
| 661 | } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); |
| 662 | |
| 663 | current->bio_list = NULL; |
| 664 | } |
| 665 | |
| 666 | static void __submit_bio_noacct_mq(struct bio *bio) |
| 667 | { |
| 668 | struct bio_list bio_list[2] = { }; |
| 669 | |
| 670 | current->bio_list = bio_list; |
| 671 | |
| 672 | do { |
| 673 | __submit_bio(bio); |
| 674 | } while ((bio = bio_list_pop(&bio_list[0]))); |
| 675 | |
| 676 | current->bio_list = NULL; |
| 677 | } |
| 678 | |
| 679 | void submit_bio_noacct_nocheck(struct bio *bio) |
| 680 | { |
| 681 | blk_cgroup_bio_start(bio); |
| 682 | blkcg_bio_issue_init(bio); |
| 683 | |
| 684 | if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
| 685 | trace_block_bio_queue(bio); |
| 686 | /* |
| 687 | * Now that enqueuing has been traced, we need to trace |
| 688 | * completion as well. |
| 689 | */ |
| 690 | bio_set_flag(bio, BIO_TRACE_COMPLETION); |
| 691 | } |
| 692 | |
| 693 | /* |
| 694 | * We only want one ->submit_bio to be active at a time, else stack |
| 695 | * usage with stacked devices could be a problem. Use current->bio_list |
| 696 | * to collect a list of requests submited by a ->submit_bio method while |
| 697 | * it is active, and then process them after it returned. |
| 698 | */ |
| 699 | if (current->bio_list) |
| 700 | bio_list_add(¤t->bio_list[0], bio); |
| 701 | else if (!bio->bi_bdev->bd_has_submit_bio) |
| 702 | __submit_bio_noacct_mq(bio); |
| 703 | else |
| 704 | __submit_bio_noacct(bio); |
| 705 | } |
| 706 | |
| 707 | /** |
| 708 | * submit_bio_noacct - re-submit a bio to the block device layer for I/O |
| 709 | * @bio: The bio describing the location in memory and on the device. |
| 710 | * |
| 711 | * This is a version of submit_bio() that shall only be used for I/O that is |
| 712 | * resubmitted to lower level drivers by stacking block drivers. All file |
| 713 | * systems and other upper level users of the block layer should use |
| 714 | * submit_bio() instead. |
| 715 | */ |
| 716 | void submit_bio_noacct(struct bio *bio) |
| 717 | { |
| 718 | struct block_device *bdev = bio->bi_bdev; |
| 719 | struct request_queue *q = bdev_get_queue(bdev); |
| 720 | blk_status_t status = BLK_STS_IOERR; |
| 721 | struct blk_plug *plug; |
| 722 | |
| 723 | might_sleep(); |
| 724 | |
| 725 | plug = blk_mq_plug(bio); |
| 726 | if (plug && plug->nowait) |
| 727 | bio->bi_opf |= REQ_NOWAIT; |
| 728 | |
| 729 | /* |
| 730 | * For a REQ_NOWAIT based request, return -EOPNOTSUPP |
| 731 | * if queue does not support NOWAIT. |
| 732 | */ |
| 733 | if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev)) |
| 734 | goto not_supported; |
| 735 | |
| 736 | if (should_fail_bio(bio)) |
| 737 | goto end_io; |
| 738 | bio_check_ro(bio); |
| 739 | if (!bio_flagged(bio, BIO_REMAPPED)) { |
| 740 | if (unlikely(bio_check_eod(bio))) |
| 741 | goto end_io; |
| 742 | if (bdev->bd_partno && unlikely(blk_partition_remap(bio))) |
| 743 | goto end_io; |
| 744 | } |
| 745 | |
| 746 | /* |
| 747 | * Filter flush bio's early so that bio based drivers without flush |
| 748 | * support don't have to worry about them. |
| 749 | */ |
| 750 | if (op_is_flush(bio->bi_opf)) { |
| 751 | if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE && |
| 752 | bio_op(bio) != REQ_OP_ZONE_APPEND)) |
| 753 | goto end_io; |
| 754 | if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { |
| 755 | bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); |
| 756 | if (!bio_sectors(bio)) { |
| 757 | status = BLK_STS_OK; |
| 758 | goto end_io; |
| 759 | } |
| 760 | } |
| 761 | } |
| 762 | |
| 763 | if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
| 764 | bio_clear_polled(bio); |
| 765 | |
| 766 | switch (bio_op(bio)) { |
| 767 | case REQ_OP_DISCARD: |
| 768 | if (!bdev_max_discard_sectors(bdev)) |
| 769 | goto not_supported; |
| 770 | break; |
| 771 | case REQ_OP_SECURE_ERASE: |
| 772 | if (!bdev_max_secure_erase_sectors(bdev)) |
| 773 | goto not_supported; |
| 774 | break; |
| 775 | case REQ_OP_ZONE_APPEND: |
| 776 | status = blk_check_zone_append(q, bio); |
| 777 | if (status != BLK_STS_OK) |
| 778 | goto end_io; |
| 779 | break; |
| 780 | case REQ_OP_ZONE_RESET: |
| 781 | case REQ_OP_ZONE_OPEN: |
| 782 | case REQ_OP_ZONE_CLOSE: |
| 783 | case REQ_OP_ZONE_FINISH: |
| 784 | if (!bdev_is_zoned(bio->bi_bdev)) |
| 785 | goto not_supported; |
| 786 | break; |
| 787 | case REQ_OP_ZONE_RESET_ALL: |
| 788 | if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q)) |
| 789 | goto not_supported; |
| 790 | break; |
| 791 | case REQ_OP_WRITE_ZEROES: |
| 792 | if (!q->limits.max_write_zeroes_sectors) |
| 793 | goto not_supported; |
| 794 | break; |
| 795 | default: |
| 796 | break; |
| 797 | } |
| 798 | |
| 799 | if (blk_throtl_bio(bio)) |
| 800 | return; |
| 801 | submit_bio_noacct_nocheck(bio); |
| 802 | return; |
| 803 | |
| 804 | not_supported: |
| 805 | status = BLK_STS_NOTSUPP; |
| 806 | end_io: |
| 807 | bio->bi_status = status; |
| 808 | bio_endio(bio); |
| 809 | } |
| 810 | EXPORT_SYMBOL(submit_bio_noacct); |
| 811 | |
| 812 | /** |
| 813 | * submit_bio - submit a bio to the block device layer for I/O |
| 814 | * @bio: The &struct bio which describes the I/O |
| 815 | * |
| 816 | * submit_bio() is used to submit I/O requests to block devices. It is passed a |
| 817 | * fully set up &struct bio that describes the I/O that needs to be done. The |
| 818 | * bio will be send to the device described by the bi_bdev field. |
| 819 | * |
| 820 | * The success/failure status of the request, along with notification of |
| 821 | * completion, is delivered asynchronously through the ->bi_end_io() callback |
| 822 | * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has |
| 823 | * been called. |
| 824 | */ |
| 825 | void submit_bio(struct bio *bio) |
| 826 | { |
| 827 | if (bio_op(bio) == REQ_OP_READ) { |
| 828 | task_io_account_read(bio->bi_iter.bi_size); |
| 829 | count_vm_events(PGPGIN, bio_sectors(bio)); |
| 830 | } else if (bio_op(bio) == REQ_OP_WRITE) { |
| 831 | count_vm_events(PGPGOUT, bio_sectors(bio)); |
| 832 | } |
| 833 | |
| 834 | submit_bio_noacct(bio); |
| 835 | } |
| 836 | EXPORT_SYMBOL(submit_bio); |
| 837 | |
| 838 | /** |
| 839 | * bio_poll - poll for BIO completions |
| 840 | * @bio: bio to poll for |
| 841 | * @iob: batches of IO |
| 842 | * @flags: BLK_POLL_* flags that control the behavior |
| 843 | * |
| 844 | * Poll for completions on queue associated with the bio. Returns number of |
| 845 | * completed entries found. |
| 846 | * |
| 847 | * Note: the caller must either be the context that submitted @bio, or |
| 848 | * be in a RCU critical section to prevent freeing of @bio. |
| 849 | */ |
| 850 | int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) |
| 851 | { |
| 852 | blk_qc_t cookie = READ_ONCE(bio->bi_cookie); |
| 853 | struct block_device *bdev; |
| 854 | struct request_queue *q; |
| 855 | int ret = 0; |
| 856 | |
| 857 | bdev = READ_ONCE(bio->bi_bdev); |
| 858 | if (!bdev) |
| 859 | return 0; |
| 860 | |
| 861 | q = bdev_get_queue(bdev); |
| 862 | if (cookie == BLK_QC_T_NONE || |
| 863 | !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
| 864 | return 0; |
| 865 | |
| 866 | /* |
| 867 | * As the requests that require a zone lock are not plugged in the |
| 868 | * first place, directly accessing the plug instead of using |
| 869 | * blk_mq_plug() should not have any consequences during flushing for |
| 870 | * zoned devices. |
| 871 | */ |
| 872 | blk_flush_plug(current->plug, false); |
| 873 | |
| 874 | /* |
| 875 | * We need to be able to enter a frozen queue, similar to how |
| 876 | * timeouts also need to do that. If that is blocked, then we can |
| 877 | * have pending IO when a queue freeze is started, and then the |
| 878 | * wait for the freeze to finish will wait for polled requests to |
| 879 | * timeout as the poller is preventer from entering the queue and |
| 880 | * completing them. As long as we prevent new IO from being queued, |
| 881 | * that should be all that matters. |
| 882 | */ |
| 883 | if (!percpu_ref_tryget(&q->q_usage_counter)) |
| 884 | return 0; |
| 885 | if (queue_is_mq(q)) { |
| 886 | ret = blk_mq_poll(q, cookie, iob, flags); |
| 887 | } else { |
| 888 | struct gendisk *disk = q->disk; |
| 889 | |
| 890 | if (disk && disk->fops->poll_bio) |
| 891 | ret = disk->fops->poll_bio(bio, iob, flags); |
| 892 | } |
| 893 | blk_queue_exit(q); |
| 894 | return ret; |
| 895 | } |
| 896 | EXPORT_SYMBOL_GPL(bio_poll); |
| 897 | |
| 898 | /* |
| 899 | * Helper to implement file_operations.iopoll. Requires the bio to be stored |
| 900 | * in iocb->private, and cleared before freeing the bio. |
| 901 | */ |
| 902 | int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob, |
| 903 | unsigned int flags) |
| 904 | { |
| 905 | struct bio *bio; |
| 906 | int ret = 0; |
| 907 | |
| 908 | /* |
| 909 | * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can |
| 910 | * point to a freshly allocated bio at this point. If that happens |
| 911 | * we have a few cases to consider: |
| 912 | * |
| 913 | * 1) the bio is beeing initialized and bi_bdev is NULL. We can just |
| 914 | * simply nothing in this case |
| 915 | * 2) the bio points to a not poll enabled device. bio_poll will catch |
| 916 | * this and return 0 |
| 917 | * 3) the bio points to a poll capable device, including but not |
| 918 | * limited to the one that the original bio pointed to. In this |
| 919 | * case we will call into the actual poll method and poll for I/O, |
| 920 | * even if we don't need to, but it won't cause harm either. |
| 921 | * |
| 922 | * For cases 2) and 3) above the RCU grace period ensures that bi_bdev |
| 923 | * is still allocated. Because partitions hold a reference to the whole |
| 924 | * device bdev and thus disk, the disk is also still valid. Grabbing |
| 925 | * a reference to the queue in bio_poll() ensures the hctxs and requests |
| 926 | * are still valid as well. |
| 927 | */ |
| 928 | rcu_read_lock(); |
| 929 | bio = READ_ONCE(kiocb->private); |
| 930 | if (bio) |
| 931 | ret = bio_poll(bio, iob, flags); |
| 932 | rcu_read_unlock(); |
| 933 | |
| 934 | return ret; |
| 935 | } |
| 936 | EXPORT_SYMBOL_GPL(iocb_bio_iopoll); |
| 937 | |
| 938 | void update_io_ticks(struct block_device *part, unsigned long now, bool end) |
| 939 | { |
| 940 | unsigned long stamp; |
| 941 | again: |
| 942 | stamp = READ_ONCE(part->bd_stamp); |
| 943 | if (unlikely(time_after(now, stamp))) { |
| 944 | if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now))) |
| 945 | __part_stat_add(part, io_ticks, end ? now - stamp : 1); |
| 946 | } |
| 947 | if (part->bd_partno) { |
| 948 | part = bdev_whole(part); |
| 949 | goto again; |
| 950 | } |
| 951 | } |
| 952 | |
| 953 | unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op, |
| 954 | unsigned long start_time) |
| 955 | { |
| 956 | part_stat_lock(); |
| 957 | update_io_ticks(bdev, start_time, false); |
| 958 | part_stat_local_inc(bdev, in_flight[op_is_write(op)]); |
| 959 | part_stat_unlock(); |
| 960 | |
| 961 | return start_time; |
| 962 | } |
| 963 | EXPORT_SYMBOL(bdev_start_io_acct); |
| 964 | |
| 965 | /** |
| 966 | * bio_start_io_acct - start I/O accounting for bio based drivers |
| 967 | * @bio: bio to start account for |
| 968 | * |
| 969 | * Returns the start time that should be passed back to bio_end_io_acct(). |
| 970 | */ |
| 971 | unsigned long bio_start_io_acct(struct bio *bio) |
| 972 | { |
| 973 | return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies); |
| 974 | } |
| 975 | EXPORT_SYMBOL_GPL(bio_start_io_acct); |
| 976 | |
| 977 | void bdev_end_io_acct(struct block_device *bdev, enum req_op op, |
| 978 | unsigned int sectors, unsigned long start_time) |
| 979 | { |
| 980 | const int sgrp = op_stat_group(op); |
| 981 | unsigned long now = READ_ONCE(jiffies); |
| 982 | unsigned long duration = now - start_time; |
| 983 | |
| 984 | part_stat_lock(); |
| 985 | update_io_ticks(bdev, now, true); |
| 986 | part_stat_inc(bdev, ios[sgrp]); |
| 987 | part_stat_add(bdev, sectors[sgrp], sectors); |
| 988 | part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration)); |
| 989 | part_stat_local_dec(bdev, in_flight[op_is_write(op)]); |
| 990 | part_stat_unlock(); |
| 991 | } |
| 992 | EXPORT_SYMBOL(bdev_end_io_acct); |
| 993 | |
| 994 | void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, |
| 995 | struct block_device *orig_bdev) |
| 996 | { |
| 997 | bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time); |
| 998 | } |
| 999 | EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped); |
| 1000 | |
| 1001 | /** |
| 1002 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy |
| 1003 | * @q : the queue of the device being checked |
| 1004 | * |
| 1005 | * Description: |
| 1006 | * Check if underlying low-level drivers of a device are busy. |
| 1007 | * If the drivers want to export their busy state, they must set own |
| 1008 | * exporting function using blk_queue_lld_busy() first. |
| 1009 | * |
| 1010 | * Basically, this function is used only by request stacking drivers |
| 1011 | * to stop dispatching requests to underlying devices when underlying |
| 1012 | * devices are busy. This behavior helps more I/O merging on the queue |
| 1013 | * of the request stacking driver and prevents I/O throughput regression |
| 1014 | * on burst I/O load. |
| 1015 | * |
| 1016 | * Return: |
| 1017 | * 0 - Not busy (The request stacking driver should dispatch request) |
| 1018 | * 1 - Busy (The request stacking driver should stop dispatching request) |
| 1019 | */ |
| 1020 | int blk_lld_busy(struct request_queue *q) |
| 1021 | { |
| 1022 | if (queue_is_mq(q) && q->mq_ops->busy) |
| 1023 | return q->mq_ops->busy(q); |
| 1024 | |
| 1025 | return 0; |
| 1026 | } |
| 1027 | EXPORT_SYMBOL_GPL(blk_lld_busy); |
| 1028 | |
| 1029 | int kblockd_schedule_work(struct work_struct *work) |
| 1030 | { |
| 1031 | return queue_work(kblockd_workqueue, work); |
| 1032 | } |
| 1033 | EXPORT_SYMBOL(kblockd_schedule_work); |
| 1034 | |
| 1035 | int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, |
| 1036 | unsigned long delay) |
| 1037 | { |
| 1038 | return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); |
| 1039 | } |
| 1040 | EXPORT_SYMBOL(kblockd_mod_delayed_work_on); |
| 1041 | |
| 1042 | void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) |
| 1043 | { |
| 1044 | struct task_struct *tsk = current; |
| 1045 | |
| 1046 | /* |
| 1047 | * If this is a nested plug, don't actually assign it. |
| 1048 | */ |
| 1049 | if (tsk->plug) |
| 1050 | return; |
| 1051 | |
| 1052 | plug->mq_list = NULL; |
| 1053 | plug->cached_rq = NULL; |
| 1054 | plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); |
| 1055 | plug->rq_count = 0; |
| 1056 | plug->multiple_queues = false; |
| 1057 | plug->has_elevator = false; |
| 1058 | plug->nowait = false; |
| 1059 | INIT_LIST_HEAD(&plug->cb_list); |
| 1060 | |
| 1061 | /* |
| 1062 | * Store ordering should not be needed here, since a potential |
| 1063 | * preempt will imply a full memory barrier |
| 1064 | */ |
| 1065 | tsk->plug = plug; |
| 1066 | } |
| 1067 | |
| 1068 | /** |
| 1069 | * blk_start_plug - initialize blk_plug and track it inside the task_struct |
| 1070 | * @plug: The &struct blk_plug that needs to be initialized |
| 1071 | * |
| 1072 | * Description: |
| 1073 | * blk_start_plug() indicates to the block layer an intent by the caller |
| 1074 | * to submit multiple I/O requests in a batch. The block layer may use |
| 1075 | * this hint to defer submitting I/Os from the caller until blk_finish_plug() |
| 1076 | * is called. However, the block layer may choose to submit requests |
| 1077 | * before a call to blk_finish_plug() if the number of queued I/Os |
| 1078 | * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than |
| 1079 | * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if |
| 1080 | * the task schedules (see below). |
| 1081 | * |
| 1082 | * Tracking blk_plug inside the task_struct will help with auto-flushing the |
| 1083 | * pending I/O should the task end up blocking between blk_start_plug() and |
| 1084 | * blk_finish_plug(). This is important from a performance perspective, but |
| 1085 | * also ensures that we don't deadlock. For instance, if the task is blocking |
| 1086 | * for a memory allocation, memory reclaim could end up wanting to free a |
| 1087 | * page belonging to that request that is currently residing in our private |
| 1088 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid |
| 1089 | * this kind of deadlock. |
| 1090 | */ |
| 1091 | void blk_start_plug(struct blk_plug *plug) |
| 1092 | { |
| 1093 | blk_start_plug_nr_ios(plug, 1); |
| 1094 | } |
| 1095 | EXPORT_SYMBOL(blk_start_plug); |
| 1096 | |
| 1097 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
| 1098 | { |
| 1099 | LIST_HEAD(callbacks); |
| 1100 | |
| 1101 | while (!list_empty(&plug->cb_list)) { |
| 1102 | list_splice_init(&plug->cb_list, &callbacks); |
| 1103 | |
| 1104 | while (!list_empty(&callbacks)) { |
| 1105 | struct blk_plug_cb *cb = list_first_entry(&callbacks, |
| 1106 | struct blk_plug_cb, |
| 1107 | list); |
| 1108 | list_del(&cb->list); |
| 1109 | cb->callback(cb, from_schedule); |
| 1110 | } |
| 1111 | } |
| 1112 | } |
| 1113 | |
| 1114 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
| 1115 | int size) |
| 1116 | { |
| 1117 | struct blk_plug *plug = current->plug; |
| 1118 | struct blk_plug_cb *cb; |
| 1119 | |
| 1120 | if (!plug) |
| 1121 | return NULL; |
| 1122 | |
| 1123 | list_for_each_entry(cb, &plug->cb_list, list) |
| 1124 | if (cb->callback == unplug && cb->data == data) |
| 1125 | return cb; |
| 1126 | |
| 1127 | /* Not currently on the callback list */ |
| 1128 | BUG_ON(size < sizeof(*cb)); |
| 1129 | cb = kzalloc(size, GFP_ATOMIC); |
| 1130 | if (cb) { |
| 1131 | cb->data = data; |
| 1132 | cb->callback = unplug; |
| 1133 | list_add(&cb->list, &plug->cb_list); |
| 1134 | } |
| 1135 | return cb; |
| 1136 | } |
| 1137 | EXPORT_SYMBOL(blk_check_plugged); |
| 1138 | |
| 1139 | void __blk_flush_plug(struct blk_plug *plug, bool from_schedule) |
| 1140 | { |
| 1141 | if (!list_empty(&plug->cb_list)) |
| 1142 | flush_plug_callbacks(plug, from_schedule); |
| 1143 | if (!rq_list_empty(plug->mq_list)) |
| 1144 | blk_mq_flush_plug_list(plug, from_schedule); |
| 1145 | /* |
| 1146 | * Unconditionally flush out cached requests, even if the unplug |
| 1147 | * event came from schedule. Since we know hold references to the |
| 1148 | * queue for cached requests, we don't want a blocked task holding |
| 1149 | * up a queue freeze/quiesce event. |
| 1150 | */ |
| 1151 | if (unlikely(!rq_list_empty(plug->cached_rq))) |
| 1152 | blk_mq_free_plug_rqs(plug); |
| 1153 | } |
| 1154 | |
| 1155 | /** |
| 1156 | * blk_finish_plug - mark the end of a batch of submitted I/O |
| 1157 | * @plug: The &struct blk_plug passed to blk_start_plug() |
| 1158 | * |
| 1159 | * Description: |
| 1160 | * Indicate that a batch of I/O submissions is complete. This function |
| 1161 | * must be paired with an initial call to blk_start_plug(). The intent |
| 1162 | * is to allow the block layer to optimize I/O submission. See the |
| 1163 | * documentation for blk_start_plug() for more information. |
| 1164 | */ |
| 1165 | void blk_finish_plug(struct blk_plug *plug) |
| 1166 | { |
| 1167 | if (plug == current->plug) { |
| 1168 | __blk_flush_plug(plug, false); |
| 1169 | current->plug = NULL; |
| 1170 | } |
| 1171 | } |
| 1172 | EXPORT_SYMBOL(blk_finish_plug); |
| 1173 | |
| 1174 | void blk_io_schedule(void) |
| 1175 | { |
| 1176 | /* Prevent hang_check timer from firing at us during very long I/O */ |
| 1177 | unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; |
| 1178 | |
| 1179 | if (timeout) |
| 1180 | io_schedule_timeout(timeout); |
| 1181 | else |
| 1182 | io_schedule(); |
| 1183 | } |
| 1184 | EXPORT_SYMBOL_GPL(blk_io_schedule); |
| 1185 | |
| 1186 | int __init blk_dev_init(void) |
| 1187 | { |
| 1188 | BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS)); |
| 1189 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
| 1190 | sizeof_field(struct request, cmd_flags)); |
| 1191 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
| 1192 | sizeof_field(struct bio, bi_opf)); |
| 1193 | |
| 1194 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
| 1195 | kblockd_workqueue = alloc_workqueue("kblockd", |
| 1196 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); |
| 1197 | if (!kblockd_workqueue) |
| 1198 | panic("Failed to create kblockd\n"); |
| 1199 | |
| 1200 | blk_requestq_cachep = kmem_cache_create("request_queue", |
| 1201 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
| 1202 | |
| 1203 | blk_debugfs_root = debugfs_create_dir("block", NULL); |
| 1204 | |
| 1205 | return 0; |
| 1206 | } |