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 mutex_init(&q->rq_qos_mutex); 424 spin_lock_init(&q->queue_lock); 425 426 init_waitqueue_head(&q->mq_freeze_wq); 427 mutex_init(&q->mq_freeze_lock); 428 429 /* 430 * Init percpu_ref in atomic mode so that it's faster to shutdown. 431 * See blk_register_queue() for details. 432 */ 433 if (percpu_ref_init(&q->q_usage_counter, 434 blk_queue_usage_counter_release, 435 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) 436 goto fail_stats; 437 438 blk_set_default_limits(&q->limits); 439 q->nr_requests = BLKDEV_DEFAULT_RQ; 440 441 return q; 442 443 fail_stats: 444 blk_free_queue_stats(q->stats); 445 fail_id: 446 ida_free(&blk_queue_ida, q->id); 447 fail_q: 448 kmem_cache_free(blk_requestq_cachep, q); 449 return NULL; 450 } 451 452 /** 453 * blk_get_queue - increment the request_queue refcount 454 * @q: the request_queue structure to increment the refcount for 455 * 456 * Increment the refcount of the request_queue kobject. 457 * 458 * Context: Any context. 459 */ 460 bool blk_get_queue(struct request_queue *q) 461 { 462 if (unlikely(blk_queue_dying(q))) 463 return false; 464 refcount_inc(&q->refs); 465 return true; 466 } 467 EXPORT_SYMBOL(blk_get_queue); 468 469 #ifdef CONFIG_FAIL_MAKE_REQUEST 470 471 static DECLARE_FAULT_ATTR(fail_make_request); 472 473 static int __init setup_fail_make_request(char *str) 474 { 475 return setup_fault_attr(&fail_make_request, str); 476 } 477 __setup("fail_make_request=", setup_fail_make_request); 478 479 bool should_fail_request(struct block_device *part, unsigned int bytes) 480 { 481 return part->bd_make_it_fail && should_fail(&fail_make_request, bytes); 482 } 483 484 static int __init fail_make_request_debugfs(void) 485 { 486 struct dentry *dir = fault_create_debugfs_attr("fail_make_request", 487 NULL, &fail_make_request); 488 489 return PTR_ERR_OR_ZERO(dir); 490 } 491 492 late_initcall(fail_make_request_debugfs); 493 #endif /* CONFIG_FAIL_MAKE_REQUEST */ 494 495 static inline void bio_check_ro(struct bio *bio) 496 { 497 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) { 498 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) 499 return; 500 pr_warn("Trying to write to read-only block-device %pg\n", 501 bio->bi_bdev); 502 /* Older lvm-tools actually trigger this */ 503 } 504 } 505 506 static noinline int should_fail_bio(struct bio *bio) 507 { 508 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size)) 509 return -EIO; 510 return 0; 511 } 512 ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); 513 514 /* 515 * Check whether this bio extends beyond the end of the device or partition. 516 * This may well happen - the kernel calls bread() without checking the size of 517 * the device, e.g., when mounting a file system. 518 */ 519 static inline int bio_check_eod(struct bio *bio) 520 { 521 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); 522 unsigned int nr_sectors = bio_sectors(bio); 523 524 if (nr_sectors && 525 (nr_sectors > maxsector || 526 bio->bi_iter.bi_sector > maxsector - nr_sectors)) { 527 pr_info_ratelimited("%s: attempt to access beyond end of device\n" 528 "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n", 529 current->comm, bio->bi_bdev, bio->bi_opf, 530 bio->bi_iter.bi_sector, nr_sectors, maxsector); 531 return -EIO; 532 } 533 return 0; 534 } 535 536 /* 537 * Remap block n of partition p to block n+start(p) of the disk. 538 */ 539 static int blk_partition_remap(struct bio *bio) 540 { 541 struct block_device *p = bio->bi_bdev; 542 543 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) 544 return -EIO; 545 if (bio_sectors(bio)) { 546 bio->bi_iter.bi_sector += p->bd_start_sect; 547 trace_block_bio_remap(bio, p->bd_dev, 548 bio->bi_iter.bi_sector - 549 p->bd_start_sect); 550 } 551 bio_set_flag(bio, BIO_REMAPPED); 552 return 0; 553 } 554 555 /* 556 * Check write append to a zoned block device. 557 */ 558 static inline blk_status_t blk_check_zone_append(struct request_queue *q, 559 struct bio *bio) 560 { 561 int nr_sectors = bio_sectors(bio); 562 563 /* Only applicable to zoned block devices */ 564 if (!bdev_is_zoned(bio->bi_bdev)) 565 return BLK_STS_NOTSUPP; 566 567 /* The bio sector must point to the start of a sequential zone */ 568 if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) || 569 !bio_zone_is_seq(bio)) 570 return BLK_STS_IOERR; 571 572 /* 573 * Not allowed to cross zone boundaries. Otherwise, the BIO will be 574 * split and could result in non-contiguous sectors being written in 575 * different zones. 576 */ 577 if (nr_sectors > q->limits.chunk_sectors) 578 return BLK_STS_IOERR; 579 580 /* Make sure the BIO is small enough and will not get split */ 581 if (nr_sectors > q->limits.max_zone_append_sectors) 582 return BLK_STS_IOERR; 583 584 bio->bi_opf |= REQ_NOMERGE; 585 586 return BLK_STS_OK; 587 } 588 589 static void __submit_bio(struct bio *bio) 590 { 591 if (unlikely(!blk_crypto_bio_prep(&bio))) 592 return; 593 594 if (!bio->bi_bdev->bd_has_submit_bio) { 595 blk_mq_submit_bio(bio); 596 } else if (likely(bio_queue_enter(bio) == 0)) { 597 struct gendisk *disk = bio->bi_bdev->bd_disk; 598 599 disk->fops->submit_bio(bio); 600 blk_queue_exit(disk->queue); 601 } 602 } 603 604 /* 605 * The loop in this function may be a bit non-obvious, and so deserves some 606 * explanation: 607 * 608 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure 609 * that), so we have a list with a single bio. 610 * - We pretend that we have just taken it off a longer list, so we assign 611 * bio_list to a pointer to the bio_list_on_stack, thus initialising the 612 * bio_list of new bios to be added. ->submit_bio() may indeed add some more 613 * bios through a recursive call to submit_bio_noacct. If it did, we find a 614 * non-NULL value in bio_list and re-enter the loop from the top. 615 * - In this case we really did just take the bio of the top of the list (no 616 * pretending) and so remove it from bio_list, and call into ->submit_bio() 617 * again. 618 * 619 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. 620 * bio_list_on_stack[1] contains bios that were submitted before the current 621 * ->submit_bio, but that haven't been processed yet. 622 */ 623 static void __submit_bio_noacct(struct bio *bio) 624 { 625 struct bio_list bio_list_on_stack[2]; 626 627 BUG_ON(bio->bi_next); 628 629 bio_list_init(&bio_list_on_stack[0]); 630 current->bio_list = bio_list_on_stack; 631 632 do { 633 struct request_queue *q = bdev_get_queue(bio->bi_bdev); 634 struct bio_list lower, same; 635 636 /* 637 * Create a fresh bio_list for all subordinate requests. 638 */ 639 bio_list_on_stack[1] = bio_list_on_stack[0]; 640 bio_list_init(&bio_list_on_stack[0]); 641 642 __submit_bio(bio); 643 644 /* 645 * Sort new bios into those for a lower level and those for the 646 * same level. 647 */ 648 bio_list_init(&lower); 649 bio_list_init(&same); 650 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) 651 if (q == bdev_get_queue(bio->bi_bdev)) 652 bio_list_add(&same, bio); 653 else 654 bio_list_add(&lower, bio); 655 656 /* 657 * Now assemble so we handle the lowest level first. 658 */ 659 bio_list_merge(&bio_list_on_stack[0], &lower); 660 bio_list_merge(&bio_list_on_stack[0], &same); 661 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); 662 } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); 663 664 current->bio_list = NULL; 665 } 666 667 static void __submit_bio_noacct_mq(struct bio *bio) 668 { 669 struct bio_list bio_list[2] = { }; 670 671 current->bio_list = bio_list; 672 673 do { 674 __submit_bio(bio); 675 } while ((bio = bio_list_pop(&bio_list[0]))); 676 677 current->bio_list = NULL; 678 } 679 680 void submit_bio_noacct_nocheck(struct bio *bio) 681 { 682 blk_cgroup_bio_start(bio); 683 blkcg_bio_issue_init(bio); 684 685 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { 686 trace_block_bio_queue(bio); 687 /* 688 * Now that enqueuing has been traced, we need to trace 689 * completion as well. 690 */ 691 bio_set_flag(bio, BIO_TRACE_COMPLETION); 692 } 693 694 /* 695 * We only want one ->submit_bio to be active at a time, else stack 696 * usage with stacked devices could be a problem. Use current->bio_list 697 * to collect a list of requests submited by a ->submit_bio method while 698 * it is active, and then process them after it returned. 699 */ 700 if (current->bio_list) 701 bio_list_add(¤t->bio_list[0], bio); 702 else if (!bio->bi_bdev->bd_has_submit_bio) 703 __submit_bio_noacct_mq(bio); 704 else 705 __submit_bio_noacct(bio); 706 } 707 708 /** 709 * submit_bio_noacct - re-submit a bio to the block device layer for I/O 710 * @bio: The bio describing the location in memory and on the device. 711 * 712 * This is a version of submit_bio() that shall only be used for I/O that is 713 * resubmitted to lower level drivers by stacking block drivers. All file 714 * systems and other upper level users of the block layer should use 715 * submit_bio() instead. 716 */ 717 void submit_bio_noacct(struct bio *bio) 718 { 719 struct block_device *bdev = bio->bi_bdev; 720 struct request_queue *q = bdev_get_queue(bdev); 721 blk_status_t status = BLK_STS_IOERR; 722 struct blk_plug *plug; 723 724 might_sleep(); 725 726 plug = blk_mq_plug(bio); 727 if (plug && plug->nowait) 728 bio->bi_opf |= REQ_NOWAIT; 729 730 /* 731 * For a REQ_NOWAIT based request, return -EOPNOTSUPP 732 * if queue does not support NOWAIT. 733 */ 734 if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev)) 735 goto not_supported; 736 737 if (should_fail_bio(bio)) 738 goto end_io; 739 bio_check_ro(bio); 740 if (!bio_flagged(bio, BIO_REMAPPED)) { 741 if (unlikely(bio_check_eod(bio))) 742 goto end_io; 743 if (bdev->bd_partno && unlikely(blk_partition_remap(bio))) 744 goto end_io; 745 } 746 747 /* 748 * Filter flush bio's early so that bio based drivers without flush 749 * support don't have to worry about them. 750 */ 751 if (op_is_flush(bio->bi_opf)) { 752 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE && 753 bio_op(bio) != REQ_OP_ZONE_APPEND)) 754 goto end_io; 755 if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 756 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); 757 if (!bio_sectors(bio)) { 758 status = BLK_STS_OK; 759 goto end_io; 760 } 761 } 762 } 763 764 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 765 bio_clear_polled(bio); 766 767 switch (bio_op(bio)) { 768 case REQ_OP_DISCARD: 769 if (!bdev_max_discard_sectors(bdev)) 770 goto not_supported; 771 break; 772 case REQ_OP_SECURE_ERASE: 773 if (!bdev_max_secure_erase_sectors(bdev)) 774 goto not_supported; 775 break; 776 case REQ_OP_ZONE_APPEND: 777 status = blk_check_zone_append(q, bio); 778 if (status != BLK_STS_OK) 779 goto end_io; 780 break; 781 case REQ_OP_ZONE_RESET: 782 case REQ_OP_ZONE_OPEN: 783 case REQ_OP_ZONE_CLOSE: 784 case REQ_OP_ZONE_FINISH: 785 if (!bdev_is_zoned(bio->bi_bdev)) 786 goto not_supported; 787 break; 788 case REQ_OP_ZONE_RESET_ALL: 789 if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q)) 790 goto not_supported; 791 break; 792 case REQ_OP_WRITE_ZEROES: 793 if (!q->limits.max_write_zeroes_sectors) 794 goto not_supported; 795 break; 796 default: 797 break; 798 } 799 800 if (blk_throtl_bio(bio)) 801 return; 802 submit_bio_noacct_nocheck(bio); 803 return; 804 805 not_supported: 806 status = BLK_STS_NOTSUPP; 807 end_io: 808 bio->bi_status = status; 809 bio_endio(bio); 810 } 811 EXPORT_SYMBOL(submit_bio_noacct); 812 813 /** 814 * submit_bio - submit a bio to the block device layer for I/O 815 * @bio: The &struct bio which describes the I/O 816 * 817 * submit_bio() is used to submit I/O requests to block devices. It is passed a 818 * fully set up &struct bio that describes the I/O that needs to be done. The 819 * bio will be send to the device described by the bi_bdev field. 820 * 821 * The success/failure status of the request, along with notification of 822 * completion, is delivered asynchronously through the ->bi_end_io() callback 823 * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has 824 * been called. 825 */ 826 void submit_bio(struct bio *bio) 827 { 828 if (bio_op(bio) == REQ_OP_READ) { 829 task_io_account_read(bio->bi_iter.bi_size); 830 count_vm_events(PGPGIN, bio_sectors(bio)); 831 } else if (bio_op(bio) == REQ_OP_WRITE) { 832 count_vm_events(PGPGOUT, bio_sectors(bio)); 833 } 834 835 submit_bio_noacct(bio); 836 } 837 EXPORT_SYMBOL(submit_bio); 838 839 /** 840 * bio_poll - poll for BIO completions 841 * @bio: bio to poll for 842 * @iob: batches of IO 843 * @flags: BLK_POLL_* flags that control the behavior 844 * 845 * Poll for completions on queue associated with the bio. Returns number of 846 * completed entries found. 847 * 848 * Note: the caller must either be the context that submitted @bio, or 849 * be in a RCU critical section to prevent freeing of @bio. 850 */ 851 int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) 852 { 853 blk_qc_t cookie = READ_ONCE(bio->bi_cookie); 854 struct block_device *bdev; 855 struct request_queue *q; 856 int ret = 0; 857 858 bdev = READ_ONCE(bio->bi_bdev); 859 if (!bdev) 860 return 0; 861 862 q = bdev_get_queue(bdev); 863 if (cookie == BLK_QC_T_NONE || 864 !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 865 return 0; 866 867 /* 868 * As the requests that require a zone lock are not plugged in the 869 * first place, directly accessing the plug instead of using 870 * blk_mq_plug() should not have any consequences during flushing for 871 * zoned devices. 872 */ 873 blk_flush_plug(current->plug, false); 874 875 /* 876 * We need to be able to enter a frozen queue, similar to how 877 * timeouts also need to do that. If that is blocked, then we can 878 * have pending IO when a queue freeze is started, and then the 879 * wait for the freeze to finish will wait for polled requests to 880 * timeout as the poller is preventer from entering the queue and 881 * completing them. As long as we prevent new IO from being queued, 882 * that should be all that matters. 883 */ 884 if (!percpu_ref_tryget(&q->q_usage_counter)) 885 return 0; 886 if (queue_is_mq(q)) { 887 ret = blk_mq_poll(q, cookie, iob, flags); 888 } else { 889 struct gendisk *disk = q->disk; 890 891 if (disk && disk->fops->poll_bio) 892 ret = disk->fops->poll_bio(bio, iob, flags); 893 } 894 blk_queue_exit(q); 895 return ret; 896 } 897 EXPORT_SYMBOL_GPL(bio_poll); 898 899 /* 900 * Helper to implement file_operations.iopoll. Requires the bio to be stored 901 * in iocb->private, and cleared before freeing the bio. 902 */ 903 int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob, 904 unsigned int flags) 905 { 906 struct bio *bio; 907 int ret = 0; 908 909 /* 910 * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can 911 * point to a freshly allocated bio at this point. If that happens 912 * we have a few cases to consider: 913 * 914 * 1) the bio is beeing initialized and bi_bdev is NULL. We can just 915 * simply nothing in this case 916 * 2) the bio points to a not poll enabled device. bio_poll will catch 917 * this and return 0 918 * 3) the bio points to a poll capable device, including but not 919 * limited to the one that the original bio pointed to. In this 920 * case we will call into the actual poll method and poll for I/O, 921 * even if we don't need to, but it won't cause harm either. 922 * 923 * For cases 2) and 3) above the RCU grace period ensures that bi_bdev 924 * is still allocated. Because partitions hold a reference to the whole 925 * device bdev and thus disk, the disk is also still valid. Grabbing 926 * a reference to the queue in bio_poll() ensures the hctxs and requests 927 * are still valid as well. 928 */ 929 rcu_read_lock(); 930 bio = READ_ONCE(kiocb->private); 931 if (bio) 932 ret = bio_poll(bio, iob, flags); 933 rcu_read_unlock(); 934 935 return ret; 936 } 937 EXPORT_SYMBOL_GPL(iocb_bio_iopoll); 938 939 void update_io_ticks(struct block_device *part, unsigned long now, bool end) 940 { 941 unsigned long stamp; 942 again: 943 stamp = READ_ONCE(part->bd_stamp); 944 if (unlikely(time_after(now, stamp))) { 945 if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now))) 946 __part_stat_add(part, io_ticks, end ? now - stamp : 1); 947 } 948 if (part->bd_partno) { 949 part = bdev_whole(part); 950 goto again; 951 } 952 } 953 954 unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op, 955 unsigned long start_time) 956 { 957 part_stat_lock(); 958 update_io_ticks(bdev, start_time, false); 959 part_stat_local_inc(bdev, in_flight[op_is_write(op)]); 960 part_stat_unlock(); 961 962 return start_time; 963 } 964 EXPORT_SYMBOL(bdev_start_io_acct); 965 966 /** 967 * bio_start_io_acct - start I/O accounting for bio based drivers 968 * @bio: bio to start account for 969 * 970 * Returns the start time that should be passed back to bio_end_io_acct(). 971 */ 972 unsigned long bio_start_io_acct(struct bio *bio) 973 { 974 return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies); 975 } 976 EXPORT_SYMBOL_GPL(bio_start_io_acct); 977 978 void bdev_end_io_acct(struct block_device *bdev, enum req_op op, 979 unsigned int sectors, unsigned long start_time) 980 { 981 const int sgrp = op_stat_group(op); 982 unsigned long now = READ_ONCE(jiffies); 983 unsigned long duration = now - start_time; 984 985 part_stat_lock(); 986 update_io_ticks(bdev, now, true); 987 part_stat_inc(bdev, ios[sgrp]); 988 part_stat_add(bdev, sectors[sgrp], sectors); 989 part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration)); 990 part_stat_local_dec(bdev, in_flight[op_is_write(op)]); 991 part_stat_unlock(); 992 } 993 EXPORT_SYMBOL(bdev_end_io_acct); 994 995 void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, 996 struct block_device *orig_bdev) 997 { 998 bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time); 999 } 1000 EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped); 1001 1002 /** 1003 * blk_lld_busy - Check if underlying low-level drivers of a device are busy 1004 * @q : the queue of the device being checked 1005 * 1006 * Description: 1007 * Check if underlying low-level drivers of a device are busy. 1008 * If the drivers want to export their busy state, they must set own 1009 * exporting function using blk_queue_lld_busy() first. 1010 * 1011 * Basically, this function is used only by request stacking drivers 1012 * to stop dispatching requests to underlying devices when underlying 1013 * devices are busy. This behavior helps more I/O merging on the queue 1014 * of the request stacking driver and prevents I/O throughput regression 1015 * on burst I/O load. 1016 * 1017 * Return: 1018 * 0 - Not busy (The request stacking driver should dispatch request) 1019 * 1 - Busy (The request stacking driver should stop dispatching request) 1020 */ 1021 int blk_lld_busy(struct request_queue *q) 1022 { 1023 if (queue_is_mq(q) && q->mq_ops->busy) 1024 return q->mq_ops->busy(q); 1025 1026 return 0; 1027 } 1028 EXPORT_SYMBOL_GPL(blk_lld_busy); 1029 1030 int kblockd_schedule_work(struct work_struct *work) 1031 { 1032 return queue_work(kblockd_workqueue, work); 1033 } 1034 EXPORT_SYMBOL(kblockd_schedule_work); 1035 1036 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, 1037 unsigned long delay) 1038 { 1039 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); 1040 } 1041 EXPORT_SYMBOL(kblockd_mod_delayed_work_on); 1042 1043 void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) 1044 { 1045 struct task_struct *tsk = current; 1046 1047 /* 1048 * If this is a nested plug, don't actually assign it. 1049 */ 1050 if (tsk->plug) 1051 return; 1052 1053 plug->mq_list = NULL; 1054 plug->cached_rq = NULL; 1055 plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); 1056 plug->rq_count = 0; 1057 plug->multiple_queues = false; 1058 plug->has_elevator = false; 1059 plug->nowait = false; 1060 INIT_LIST_HEAD(&plug->cb_list); 1061 1062 /* 1063 * Store ordering should not be needed here, since a potential 1064 * preempt will imply a full memory barrier 1065 */ 1066 tsk->plug = plug; 1067 } 1068 1069 /** 1070 * blk_start_plug - initialize blk_plug and track it inside the task_struct 1071 * @plug: The &struct blk_plug that needs to be initialized 1072 * 1073 * Description: 1074 * blk_start_plug() indicates to the block layer an intent by the caller 1075 * to submit multiple I/O requests in a batch. The block layer may use 1076 * this hint to defer submitting I/Os from the caller until blk_finish_plug() 1077 * is called. However, the block layer may choose to submit requests 1078 * before a call to blk_finish_plug() if the number of queued I/Os 1079 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than 1080 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if 1081 * the task schedules (see below). 1082 * 1083 * Tracking blk_plug inside the task_struct will help with auto-flushing the 1084 * pending I/O should the task end up blocking between blk_start_plug() and 1085 * blk_finish_plug(). This is important from a performance perspective, but 1086 * also ensures that we don't deadlock. For instance, if the task is blocking 1087 * for a memory allocation, memory reclaim could end up wanting to free a 1088 * page belonging to that request that is currently residing in our private 1089 * plug. By flushing the pending I/O when the process goes to sleep, we avoid 1090 * this kind of deadlock. 1091 */ 1092 void blk_start_plug(struct blk_plug *plug) 1093 { 1094 blk_start_plug_nr_ios(plug, 1); 1095 } 1096 EXPORT_SYMBOL(blk_start_plug); 1097 1098 static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) 1099 { 1100 LIST_HEAD(callbacks); 1101 1102 while (!list_empty(&plug->cb_list)) { 1103 list_splice_init(&plug->cb_list, &callbacks); 1104 1105 while (!list_empty(&callbacks)) { 1106 struct blk_plug_cb *cb = list_first_entry(&callbacks, 1107 struct blk_plug_cb, 1108 list); 1109 list_del(&cb->list); 1110 cb->callback(cb, from_schedule); 1111 } 1112 } 1113 } 1114 1115 struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, 1116 int size) 1117 { 1118 struct blk_plug *plug = current->plug; 1119 struct blk_plug_cb *cb; 1120 1121 if (!plug) 1122 return NULL; 1123 1124 list_for_each_entry(cb, &plug->cb_list, list) 1125 if (cb->callback == unplug && cb->data == data) 1126 return cb; 1127 1128 /* Not currently on the callback list */ 1129 BUG_ON(size < sizeof(*cb)); 1130 cb = kzalloc(size, GFP_ATOMIC); 1131 if (cb) { 1132 cb->data = data; 1133 cb->callback = unplug; 1134 list_add(&cb->list, &plug->cb_list); 1135 } 1136 return cb; 1137 } 1138 EXPORT_SYMBOL(blk_check_plugged); 1139 1140 void __blk_flush_plug(struct blk_plug *plug, bool from_schedule) 1141 { 1142 if (!list_empty(&plug->cb_list)) 1143 flush_plug_callbacks(plug, from_schedule); 1144 if (!rq_list_empty(plug->mq_list)) 1145 blk_mq_flush_plug_list(plug, from_schedule); 1146 /* 1147 * Unconditionally flush out cached requests, even if the unplug 1148 * event came from schedule. Since we know hold references to the 1149 * queue for cached requests, we don't want a blocked task holding 1150 * up a queue freeze/quiesce event. 1151 */ 1152 if (unlikely(!rq_list_empty(plug->cached_rq))) 1153 blk_mq_free_plug_rqs(plug); 1154 } 1155 1156 /** 1157 * blk_finish_plug - mark the end of a batch of submitted I/O 1158 * @plug: The &struct blk_plug passed to blk_start_plug() 1159 * 1160 * Description: 1161 * Indicate that a batch of I/O submissions is complete. This function 1162 * must be paired with an initial call to blk_start_plug(). The intent 1163 * is to allow the block layer to optimize I/O submission. See the 1164 * documentation for blk_start_plug() for more information. 1165 */ 1166 void blk_finish_plug(struct blk_plug *plug) 1167 { 1168 if (plug == current->plug) { 1169 __blk_flush_plug(plug, false); 1170 current->plug = NULL; 1171 } 1172 } 1173 EXPORT_SYMBOL(blk_finish_plug); 1174 1175 void blk_io_schedule(void) 1176 { 1177 /* Prevent hang_check timer from firing at us during very long I/O */ 1178 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; 1179 1180 if (timeout) 1181 io_schedule_timeout(timeout); 1182 else 1183 io_schedule(); 1184 } 1185 EXPORT_SYMBOL_GPL(blk_io_schedule); 1186 1187 int __init blk_dev_init(void) 1188 { 1189 BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS)); 1190 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1191 sizeof_field(struct request, cmd_flags)); 1192 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1193 sizeof_field(struct bio, bi_opf)); 1194 1195 /* used for unplugging and affects IO latency/throughput - HIGHPRI */ 1196 kblockd_workqueue = alloc_workqueue("kblockd", 1197 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); 1198 if (!kblockd_workqueue) 1199 panic("Failed to create kblockd\n"); 1200 1201 blk_requestq_cachep = kmem_cache_create("request_queue", 1202 sizeof(struct request_queue), 0, SLAB_PANIC, NULL); 1203 1204 blk_debugfs_root = debugfs_create_dir("block", NULL); 1205 1206 return 0; 1207 } 1208