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#include "blk-ioprio.h" 53 54struct dentry *blk_debugfs_root; 55 56EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); 57EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); 58EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); 59EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); 60EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); 61EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert); 62 63static DEFINE_IDA(blk_queue_ida); 64 65/* 66 * For queue allocation 67 */ 68static struct kmem_cache *blk_requestq_cachep; 69 70/* 71 * Controlling structure to kblockd 72 */ 73static struct workqueue_struct *kblockd_workqueue; 74 75/** 76 * blk_queue_flag_set - atomically set a queue flag 77 * @flag: flag to be set 78 * @q: request queue 79 */ 80void blk_queue_flag_set(unsigned int flag, struct request_queue *q) 81{ 82 set_bit(flag, &q->queue_flags); 83} 84EXPORT_SYMBOL(blk_queue_flag_set); 85 86/** 87 * blk_queue_flag_clear - atomically clear a queue flag 88 * @flag: flag to be cleared 89 * @q: request queue 90 */ 91void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) 92{ 93 clear_bit(flag, &q->queue_flags); 94} 95EXPORT_SYMBOL(blk_queue_flag_clear); 96 97/** 98 * blk_queue_flag_test_and_set - atomically test and set a queue flag 99 * @flag: flag to be set 100 * @q: request queue 101 * 102 * Returns the previous value of @flag - 0 if the flag was not set and 1 if 103 * the flag was already set. 104 */ 105bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) 106{ 107 return test_and_set_bit(flag, &q->queue_flags); 108} 109EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); 110 111#define REQ_OP_NAME(name) [REQ_OP_##name] = #name 112static const char *const blk_op_name[] = { 113 REQ_OP_NAME(READ), 114 REQ_OP_NAME(WRITE), 115 REQ_OP_NAME(FLUSH), 116 REQ_OP_NAME(DISCARD), 117 REQ_OP_NAME(SECURE_ERASE), 118 REQ_OP_NAME(ZONE_RESET), 119 REQ_OP_NAME(ZONE_RESET_ALL), 120 REQ_OP_NAME(ZONE_OPEN), 121 REQ_OP_NAME(ZONE_CLOSE), 122 REQ_OP_NAME(ZONE_FINISH), 123 REQ_OP_NAME(ZONE_APPEND), 124 REQ_OP_NAME(WRITE_ZEROES), 125 REQ_OP_NAME(DRV_IN), 126 REQ_OP_NAME(DRV_OUT), 127}; 128#undef REQ_OP_NAME 129 130/** 131 * blk_op_str - Return string XXX in the REQ_OP_XXX. 132 * @op: REQ_OP_XXX. 133 * 134 * Description: Centralize block layer function to convert REQ_OP_XXX into 135 * string format. Useful in the debugging and tracing bio or request. For 136 * invalid REQ_OP_XXX it returns string "UNKNOWN". 137 */ 138inline const char *blk_op_str(enum req_op op) 139{ 140 const char *op_str = "UNKNOWN"; 141 142 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op]) 143 op_str = blk_op_name[op]; 144 145 return op_str; 146} 147EXPORT_SYMBOL_GPL(blk_op_str); 148 149static const struct { 150 int errno; 151 const char *name; 152} blk_errors[] = { 153 [BLK_STS_OK] = { 0, "" }, 154 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, 155 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, 156 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, 157 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, 158 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, 159 [BLK_STS_RESV_CONFLICT] = { -EBADE, "reservation conflict" }, 160 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, 161 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, 162 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, 163 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, 164 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, 165 [BLK_STS_OFFLINE] = { -ENODEV, "device offline" }, 166 167 /* device mapper special case, should not leak out: */ 168 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, 169 170 /* zone device specific errors */ 171 [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" }, 172 [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" }, 173 174 /* Command duration limit device-side timeout */ 175 [BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit exceeded" }, 176 177 /* everything else not covered above: */ 178 [BLK_STS_IOERR] = { -EIO, "I/O" }, 179}; 180 181blk_status_t errno_to_blk_status(int errno) 182{ 183 int i; 184 185 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { 186 if (blk_errors[i].errno == errno) 187 return (__force blk_status_t)i; 188 } 189 190 return BLK_STS_IOERR; 191} 192EXPORT_SYMBOL_GPL(errno_to_blk_status); 193 194int blk_status_to_errno(blk_status_t status) 195{ 196 int idx = (__force int)status; 197 198 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 199 return -EIO; 200 return blk_errors[idx].errno; 201} 202EXPORT_SYMBOL_GPL(blk_status_to_errno); 203 204const char *blk_status_to_str(blk_status_t status) 205{ 206 int idx = (__force int)status; 207 208 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 209 return "<null>"; 210 return blk_errors[idx].name; 211} 212EXPORT_SYMBOL_GPL(blk_status_to_str); 213 214/** 215 * blk_sync_queue - cancel any pending callbacks on a queue 216 * @q: the queue 217 * 218 * Description: 219 * The block layer may perform asynchronous callback activity 220 * on a queue, such as calling the unplug function after a timeout. 221 * A block device may call blk_sync_queue to ensure that any 222 * such activity is cancelled, thus allowing it to release resources 223 * that the callbacks might use. The caller must already have made sure 224 * that its ->submit_bio will not re-add plugging prior to calling 225 * this function. 226 * 227 * This function does not cancel any asynchronous activity arising 228 * out of elevator or throttling code. That would require elevator_exit() 229 * and blkcg_exit_queue() to be called with queue lock initialized. 230 * 231 */ 232void blk_sync_queue(struct request_queue *q) 233{ 234 del_timer_sync(&q->timeout); 235 cancel_work_sync(&q->timeout_work); 236} 237EXPORT_SYMBOL(blk_sync_queue); 238 239/** 240 * blk_set_pm_only - increment pm_only counter 241 * @q: request queue pointer 242 */ 243void blk_set_pm_only(struct request_queue *q) 244{ 245 atomic_inc(&q->pm_only); 246} 247EXPORT_SYMBOL_GPL(blk_set_pm_only); 248 249void blk_clear_pm_only(struct request_queue *q) 250{ 251 int pm_only; 252 253 pm_only = atomic_dec_return(&q->pm_only); 254 WARN_ON_ONCE(pm_only < 0); 255 if (pm_only == 0) 256 wake_up_all(&q->mq_freeze_wq); 257} 258EXPORT_SYMBOL_GPL(blk_clear_pm_only); 259 260static void blk_free_queue_rcu(struct rcu_head *rcu_head) 261{ 262 struct request_queue *q = container_of(rcu_head, 263 struct request_queue, rcu_head); 264 265 percpu_ref_exit(&q->q_usage_counter); 266 kmem_cache_free(blk_requestq_cachep, q); 267} 268 269static void blk_free_queue(struct request_queue *q) 270{ 271 blk_free_queue_stats(q->stats); 272 if (queue_is_mq(q)) 273 blk_mq_release(q); 274 275 ida_free(&blk_queue_ida, q->id); 276 call_rcu(&q->rcu_head, blk_free_queue_rcu); 277} 278 279/** 280 * blk_put_queue - decrement the request_queue refcount 281 * @q: the request_queue structure to decrement the refcount for 282 * 283 * Decrements the refcount of the request_queue and free it when the refcount 284 * reaches 0. 285 */ 286void blk_put_queue(struct request_queue *q) 287{ 288 if (refcount_dec_and_test(&q->refs)) 289 blk_free_queue(q); 290} 291EXPORT_SYMBOL(blk_put_queue); 292 293void blk_queue_start_drain(struct request_queue *q) 294{ 295 /* 296 * When queue DYING flag is set, we need to block new req 297 * entering queue, so we call blk_freeze_queue_start() to 298 * prevent I/O from crossing blk_queue_enter(). 299 */ 300 blk_freeze_queue_start(q); 301 if (queue_is_mq(q)) 302 blk_mq_wake_waiters(q); 303 /* Make blk_queue_enter() reexamine the DYING flag. */ 304 wake_up_all(&q->mq_freeze_wq); 305} 306 307/** 308 * blk_queue_enter() - try to increase q->q_usage_counter 309 * @q: request queue pointer 310 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM 311 */ 312int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) 313{ 314 const bool pm = flags & BLK_MQ_REQ_PM; 315 316 while (!blk_try_enter_queue(q, pm)) { 317 if (flags & BLK_MQ_REQ_NOWAIT) 318 return -EAGAIN; 319 320 /* 321 * read pair of barrier in blk_freeze_queue_start(), we need to 322 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and 323 * reading .mq_freeze_depth or queue dying flag, otherwise the 324 * following wait may never return if the two reads are 325 * reordered. 326 */ 327 smp_rmb(); 328 wait_event(q->mq_freeze_wq, 329 (!q->mq_freeze_depth && 330 blk_pm_resume_queue(pm, q)) || 331 blk_queue_dying(q)); 332 if (blk_queue_dying(q)) 333 return -ENODEV; 334 } 335 336 return 0; 337} 338 339int __bio_queue_enter(struct request_queue *q, struct bio *bio) 340{ 341 while (!blk_try_enter_queue(q, false)) { 342 struct gendisk *disk = bio->bi_bdev->bd_disk; 343 344 if (bio->bi_opf & REQ_NOWAIT) { 345 if (test_bit(GD_DEAD, &disk->state)) 346 goto dead; 347 bio_wouldblock_error(bio); 348 return -EAGAIN; 349 } 350 351 /* 352 * read pair of barrier in blk_freeze_queue_start(), we need to 353 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and 354 * reading .mq_freeze_depth or queue dying flag, otherwise the 355 * following wait may never return if the two reads are 356 * reordered. 357 */ 358 smp_rmb(); 359 wait_event(q->mq_freeze_wq, 360 (!q->mq_freeze_depth && 361 blk_pm_resume_queue(false, q)) || 362 test_bit(GD_DEAD, &disk->state)); 363 if (test_bit(GD_DEAD, &disk->state)) 364 goto dead; 365 } 366 367 return 0; 368dead: 369 bio_io_error(bio); 370 return -ENODEV; 371} 372 373void blk_queue_exit(struct request_queue *q) 374{ 375 percpu_ref_put(&q->q_usage_counter); 376} 377 378static void blk_queue_usage_counter_release(struct percpu_ref *ref) 379{ 380 struct request_queue *q = 381 container_of(ref, struct request_queue, q_usage_counter); 382 383 wake_up_all(&q->mq_freeze_wq); 384} 385 386static void blk_rq_timed_out_timer(struct timer_list *t) 387{ 388 struct request_queue *q = from_timer(q, t, timeout); 389 390 kblockd_schedule_work(&q->timeout_work); 391} 392 393static void blk_timeout_work(struct work_struct *work) 394{ 395} 396 397struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id) 398{ 399 struct request_queue *q; 400 int error; 401 402 q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO, 403 node_id); 404 if (!q) 405 return ERR_PTR(-ENOMEM); 406 407 q->last_merge = NULL; 408 409 q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL); 410 if (q->id < 0) { 411 error = q->id; 412 goto fail_q; 413 } 414 415 q->stats = blk_alloc_queue_stats(); 416 if (!q->stats) { 417 error = -ENOMEM; 418 goto fail_id; 419 } 420 421 error = blk_set_default_limits(lim); 422 if (error) 423 goto fail_stats; 424 q->limits = *lim; 425 426 q->node = node_id; 427 428 atomic_set(&q->nr_active_requests_shared_tags, 0); 429 430 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); 431 INIT_WORK(&q->timeout_work, blk_timeout_work); 432 INIT_LIST_HEAD(&q->icq_list); 433 434 refcount_set(&q->refs, 1); 435 mutex_init(&q->debugfs_mutex); 436 mutex_init(&q->sysfs_lock); 437 mutex_init(&q->sysfs_dir_lock); 438 mutex_init(&q->limits_lock); 439 mutex_init(&q->rq_qos_mutex); 440 spin_lock_init(&q->queue_lock); 441 442 init_waitqueue_head(&q->mq_freeze_wq); 443 mutex_init(&q->mq_freeze_lock); 444 445 blkg_init_queue(q); 446 447 /* 448 * Init percpu_ref in atomic mode so that it's faster to shutdown. 449 * See blk_register_queue() for details. 450 */ 451 error = percpu_ref_init(&q->q_usage_counter, 452 blk_queue_usage_counter_release, 453 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL); 454 if (error) 455 goto fail_stats; 456 457 q->nr_requests = BLKDEV_DEFAULT_RQ; 458 459 return q; 460 461fail_stats: 462 blk_free_queue_stats(q->stats); 463fail_id: 464 ida_free(&blk_queue_ida, q->id); 465fail_q: 466 kmem_cache_free(blk_requestq_cachep, q); 467 return ERR_PTR(error); 468} 469 470/** 471 * blk_get_queue - increment the request_queue refcount 472 * @q: the request_queue structure to increment the refcount for 473 * 474 * Increment the refcount of the request_queue kobject. 475 * 476 * Context: Any context. 477 */ 478bool blk_get_queue(struct request_queue *q) 479{ 480 if (unlikely(blk_queue_dying(q))) 481 return false; 482 refcount_inc(&q->refs); 483 return true; 484} 485EXPORT_SYMBOL(blk_get_queue); 486 487#ifdef CONFIG_FAIL_MAKE_REQUEST 488 489static DECLARE_FAULT_ATTR(fail_make_request); 490 491static int __init setup_fail_make_request(char *str) 492{ 493 return setup_fault_attr(&fail_make_request, str); 494} 495__setup("fail_make_request=", setup_fail_make_request); 496 497bool should_fail_request(struct block_device *part, unsigned int bytes) 498{ 499 return part->bd_make_it_fail && should_fail(&fail_make_request, bytes); 500} 501 502static int __init fail_make_request_debugfs(void) 503{ 504 struct dentry *dir = fault_create_debugfs_attr("fail_make_request", 505 NULL, &fail_make_request); 506 507 return PTR_ERR_OR_ZERO(dir); 508} 509 510late_initcall(fail_make_request_debugfs); 511#endif /* CONFIG_FAIL_MAKE_REQUEST */ 512 513static inline void bio_check_ro(struct bio *bio) 514{ 515 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) { 516 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) 517 return; 518 519 if (bio->bi_bdev->bd_ro_warned) 520 return; 521 522 bio->bi_bdev->bd_ro_warned = true; 523 /* 524 * Use ioctl to set underlying disk of raid/dm to read-only 525 * will trigger this. 526 */ 527 pr_warn("Trying to write to read-only block-device %pg\n", 528 bio->bi_bdev); 529 } 530} 531 532static noinline int should_fail_bio(struct bio *bio) 533{ 534 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size)) 535 return -EIO; 536 return 0; 537} 538ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); 539 540/* 541 * Check whether this bio extends beyond the end of the device or partition. 542 * This may well happen - the kernel calls bread() without checking the size of 543 * the device, e.g., when mounting a file system. 544 */ 545static inline int bio_check_eod(struct bio *bio) 546{ 547 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); 548 unsigned int nr_sectors = bio_sectors(bio); 549 550 if (nr_sectors && 551 (nr_sectors > maxsector || 552 bio->bi_iter.bi_sector > maxsector - nr_sectors)) { 553 pr_info_ratelimited("%s: attempt to access beyond end of device\n" 554 "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n", 555 current->comm, bio->bi_bdev, bio->bi_opf, 556 bio->bi_iter.bi_sector, nr_sectors, maxsector); 557 return -EIO; 558 } 559 return 0; 560} 561 562/* 563 * Remap block n of partition p to block n+start(p) of the disk. 564 */ 565static int blk_partition_remap(struct bio *bio) 566{ 567 struct block_device *p = bio->bi_bdev; 568 569 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) 570 return -EIO; 571 if (bio_sectors(bio)) { 572 bio->bi_iter.bi_sector += p->bd_start_sect; 573 trace_block_bio_remap(bio, p->bd_dev, 574 bio->bi_iter.bi_sector - 575 p->bd_start_sect); 576 } 577 bio_set_flag(bio, BIO_REMAPPED); 578 return 0; 579} 580 581/* 582 * Check write append to a zoned block device. 583 */ 584static inline blk_status_t blk_check_zone_append(struct request_queue *q, 585 struct bio *bio) 586{ 587 int nr_sectors = bio_sectors(bio); 588 589 /* Only applicable to zoned block devices */ 590 if (!bdev_is_zoned(bio->bi_bdev)) 591 return BLK_STS_NOTSUPP; 592 593 /* The bio sector must point to the start of a sequential zone */ 594 if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) || 595 !bio_zone_is_seq(bio)) 596 return BLK_STS_IOERR; 597 598 /* 599 * Not allowed to cross zone boundaries. Otherwise, the BIO will be 600 * split and could result in non-contiguous sectors being written in 601 * different zones. 602 */ 603 if (nr_sectors > q->limits.chunk_sectors) 604 return BLK_STS_IOERR; 605 606 /* Make sure the BIO is small enough and will not get split */ 607 if (nr_sectors > q->limits.max_zone_append_sectors) 608 return BLK_STS_IOERR; 609 610 bio->bi_opf |= REQ_NOMERGE; 611 612 return BLK_STS_OK; 613} 614 615static void __submit_bio(struct bio *bio) 616{ 617 if (unlikely(!blk_crypto_bio_prep(&bio))) 618 return; 619 620 if (!bio->bi_bdev->bd_has_submit_bio) { 621 blk_mq_submit_bio(bio); 622 } else if (likely(bio_queue_enter(bio) == 0)) { 623 struct gendisk *disk = bio->bi_bdev->bd_disk; 624 625 disk->fops->submit_bio(bio); 626 blk_queue_exit(disk->queue); 627 } 628} 629 630/* 631 * The loop in this function may be a bit non-obvious, and so deserves some 632 * explanation: 633 * 634 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure 635 * that), so we have a list with a single bio. 636 * - We pretend that we have just taken it off a longer list, so we assign 637 * bio_list to a pointer to the bio_list_on_stack, thus initialising the 638 * bio_list of new bios to be added. ->submit_bio() may indeed add some more 639 * bios through a recursive call to submit_bio_noacct. If it did, we find a 640 * non-NULL value in bio_list and re-enter the loop from the top. 641 * - In this case we really did just take the bio of the top of the list (no 642 * pretending) and so remove it from bio_list, and call into ->submit_bio() 643 * again. 644 * 645 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. 646 * bio_list_on_stack[1] contains bios that were submitted before the current 647 * ->submit_bio, but that haven't been processed yet. 648 */ 649static void __submit_bio_noacct(struct bio *bio) 650{ 651 struct bio_list bio_list_on_stack[2]; 652 653 BUG_ON(bio->bi_next); 654 655 bio_list_init(&bio_list_on_stack[0]); 656 current->bio_list = bio_list_on_stack; 657 658 do { 659 struct request_queue *q = bdev_get_queue(bio->bi_bdev); 660 struct bio_list lower, same; 661 662 /* 663 * Create a fresh bio_list for all subordinate requests. 664 */ 665 bio_list_on_stack[1] = bio_list_on_stack[0]; 666 bio_list_init(&bio_list_on_stack[0]); 667 668 __submit_bio(bio); 669 670 /* 671 * Sort new bios into those for a lower level and those for the 672 * same level. 673 */ 674 bio_list_init(&lower); 675 bio_list_init(&same); 676 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) 677 if (q == bdev_get_queue(bio->bi_bdev)) 678 bio_list_add(&same, bio); 679 else 680 bio_list_add(&lower, bio); 681 682 /* 683 * Now assemble so we handle the lowest level first. 684 */ 685 bio_list_merge(&bio_list_on_stack[0], &lower); 686 bio_list_merge(&bio_list_on_stack[0], &same); 687 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); 688 } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); 689 690 current->bio_list = NULL; 691} 692 693static void __submit_bio_noacct_mq(struct bio *bio) 694{ 695 struct bio_list bio_list[2] = { }; 696 697 current->bio_list = bio_list; 698 699 do { 700 __submit_bio(bio); 701 } while ((bio = bio_list_pop(&bio_list[0]))); 702 703 current->bio_list = NULL; 704} 705 706void submit_bio_noacct_nocheck(struct bio *bio) 707{ 708 blk_cgroup_bio_start(bio); 709 blkcg_bio_issue_init(bio); 710 711 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { 712 trace_block_bio_queue(bio); 713 /* 714 * Now that enqueuing has been traced, we need to trace 715 * completion as well. 716 */ 717 bio_set_flag(bio, BIO_TRACE_COMPLETION); 718 } 719 720 /* 721 * We only want one ->submit_bio to be active at a time, else stack 722 * usage with stacked devices could be a problem. Use current->bio_list 723 * to collect a list of requests submited by a ->submit_bio method while 724 * it is active, and then process them after it returned. 725 */ 726 if (current->bio_list) 727 bio_list_add(¤t->bio_list[0], bio); 728 else if (!bio->bi_bdev->bd_has_submit_bio) 729 __submit_bio_noacct_mq(bio); 730 else 731 __submit_bio_noacct(bio); 732} 733 734/** 735 * submit_bio_noacct - re-submit a bio to the block device layer for I/O 736 * @bio: The bio describing the location in memory and on the device. 737 * 738 * This is a version of submit_bio() that shall only be used for I/O that is 739 * resubmitted to lower level drivers by stacking block drivers. All file 740 * systems and other upper level users of the block layer should use 741 * submit_bio() instead. 742 */ 743void submit_bio_noacct(struct bio *bio) 744{ 745 struct block_device *bdev = bio->bi_bdev; 746 struct request_queue *q = bdev_get_queue(bdev); 747 blk_status_t status = BLK_STS_IOERR; 748 749 might_sleep(); 750 751 /* 752 * For a REQ_NOWAIT based request, return -EOPNOTSUPP 753 * if queue does not support NOWAIT. 754 */ 755 if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev)) 756 goto not_supported; 757 758 if (should_fail_bio(bio)) 759 goto end_io; 760 bio_check_ro(bio); 761 if (!bio_flagged(bio, BIO_REMAPPED)) { 762 if (unlikely(bio_check_eod(bio))) 763 goto end_io; 764 if (bdev->bd_partno && unlikely(blk_partition_remap(bio))) 765 goto end_io; 766 } 767 768 /* 769 * Filter flush bio's early so that bio based drivers without flush 770 * support don't have to worry about them. 771 */ 772 if (op_is_flush(bio->bi_opf)) { 773 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE && 774 bio_op(bio) != REQ_OP_ZONE_APPEND)) 775 goto end_io; 776 if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 777 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); 778 if (!bio_sectors(bio)) { 779 status = BLK_STS_OK; 780 goto end_io; 781 } 782 } 783 } 784 785 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 786 bio_clear_polled(bio); 787 788 switch (bio_op(bio)) { 789 case REQ_OP_READ: 790 case REQ_OP_WRITE: 791 break; 792 case REQ_OP_FLUSH: 793 /* 794 * REQ_OP_FLUSH can't be submitted through bios, it is only 795 * synthetized in struct request by the flush state machine. 796 */ 797 goto not_supported; 798 case REQ_OP_DISCARD: 799 if (!bdev_max_discard_sectors(bdev)) 800 goto not_supported; 801 break; 802 case REQ_OP_SECURE_ERASE: 803 if (!bdev_max_secure_erase_sectors(bdev)) 804 goto not_supported; 805 break; 806 case REQ_OP_ZONE_APPEND: 807 status = blk_check_zone_append(q, bio); 808 if (status != BLK_STS_OK) 809 goto end_io; 810 break; 811 case REQ_OP_WRITE_ZEROES: 812 if (!q->limits.max_write_zeroes_sectors) 813 goto not_supported; 814 break; 815 case REQ_OP_ZONE_RESET: 816 case REQ_OP_ZONE_OPEN: 817 case REQ_OP_ZONE_CLOSE: 818 case REQ_OP_ZONE_FINISH: 819 if (!bdev_is_zoned(bio->bi_bdev)) 820 goto not_supported; 821 break; 822 case REQ_OP_ZONE_RESET_ALL: 823 if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q)) 824 goto not_supported; 825 break; 826 case REQ_OP_DRV_IN: 827 case REQ_OP_DRV_OUT: 828 /* 829 * Driver private operations are only used with passthrough 830 * requests. 831 */ 832 fallthrough; 833 default: 834 goto not_supported; 835 } 836 837 if (blk_throtl_bio(bio)) 838 return; 839 submit_bio_noacct_nocheck(bio); 840 return; 841 842not_supported: 843 status = BLK_STS_NOTSUPP; 844end_io: 845 bio->bi_status = status; 846 bio_endio(bio); 847} 848EXPORT_SYMBOL(submit_bio_noacct); 849 850static void bio_set_ioprio(struct bio *bio) 851{ 852 /* Nobody set ioprio so far? Initialize it based on task's nice value */ 853 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE) 854 bio->bi_ioprio = get_current_ioprio(); 855 blkcg_set_ioprio(bio); 856} 857 858/** 859 * submit_bio - submit a bio to the block device layer for I/O 860 * @bio: The &struct bio which describes the I/O 861 * 862 * submit_bio() is used to submit I/O requests to block devices. It is passed a 863 * fully set up &struct bio that describes the I/O that needs to be done. The 864 * bio will be send to the device described by the bi_bdev field. 865 * 866 * The success/failure status of the request, along with notification of 867 * completion, is delivered asynchronously through the ->bi_end_io() callback 868 * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has 869 * been called. 870 */ 871void submit_bio(struct bio *bio) 872{ 873 if (bio_op(bio) == REQ_OP_READ) { 874 task_io_account_read(bio->bi_iter.bi_size); 875 count_vm_events(PGPGIN, bio_sectors(bio)); 876 } else if (bio_op(bio) == REQ_OP_WRITE) { 877 count_vm_events(PGPGOUT, bio_sectors(bio)); 878 } 879 880 bio_set_ioprio(bio); 881 submit_bio_noacct(bio); 882} 883EXPORT_SYMBOL(submit_bio); 884 885/** 886 * bio_poll - poll for BIO completions 887 * @bio: bio to poll for 888 * @iob: batches of IO 889 * @flags: BLK_POLL_* flags that control the behavior 890 * 891 * Poll for completions on queue associated with the bio. Returns number of 892 * completed entries found. 893 * 894 * Note: the caller must either be the context that submitted @bio, or 895 * be in a RCU critical section to prevent freeing of @bio. 896 */ 897int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) 898{ 899 blk_qc_t cookie = READ_ONCE(bio->bi_cookie); 900 struct block_device *bdev; 901 struct request_queue *q; 902 int ret = 0; 903 904 bdev = READ_ONCE(bio->bi_bdev); 905 if (!bdev) 906 return 0; 907 908 q = bdev_get_queue(bdev); 909 if (cookie == BLK_QC_T_NONE || 910 !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 911 return 0; 912 913 /* 914 * As the requests that require a zone lock are not plugged in the 915 * first place, directly accessing the plug instead of using 916 * blk_mq_plug() should not have any consequences during flushing for 917 * zoned devices. 918 */ 919 blk_flush_plug(current->plug, false); 920 921 /* 922 * We need to be able to enter a frozen queue, similar to how 923 * timeouts also need to do that. If that is blocked, then we can 924 * have pending IO when a queue freeze is started, and then the 925 * wait for the freeze to finish will wait for polled requests to 926 * timeout as the poller is preventer from entering the queue and 927 * completing them. As long as we prevent new IO from being queued, 928 * that should be all that matters. 929 */ 930 if (!percpu_ref_tryget(&q->q_usage_counter)) 931 return 0; 932 if (queue_is_mq(q)) { 933 ret = blk_mq_poll(q, cookie, iob, flags); 934 } else { 935 struct gendisk *disk = q->disk; 936 937 if (disk && disk->fops->poll_bio) 938 ret = disk->fops->poll_bio(bio, iob, flags); 939 } 940 blk_queue_exit(q); 941 return ret; 942} 943EXPORT_SYMBOL_GPL(bio_poll); 944 945/* 946 * Helper to implement file_operations.iopoll. Requires the bio to be stored 947 * in iocb->private, and cleared before freeing the bio. 948 */ 949int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob, 950 unsigned int flags) 951{ 952 struct bio *bio; 953 int ret = 0; 954 955 /* 956 * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can 957 * point to a freshly allocated bio at this point. If that happens 958 * we have a few cases to consider: 959 * 960 * 1) the bio is beeing initialized and bi_bdev is NULL. We can just 961 * simply nothing in this case 962 * 2) the bio points to a not poll enabled device. bio_poll will catch 963 * this and return 0 964 * 3) the bio points to a poll capable device, including but not 965 * limited to the one that the original bio pointed to. In this 966 * case we will call into the actual poll method and poll for I/O, 967 * even if we don't need to, but it won't cause harm either. 968 * 969 * For cases 2) and 3) above the RCU grace period ensures that bi_bdev 970 * is still allocated. Because partitions hold a reference to the whole 971 * device bdev and thus disk, the disk is also still valid. Grabbing 972 * a reference to the queue in bio_poll() ensures the hctxs and requests 973 * are still valid as well. 974 */ 975 rcu_read_lock(); 976 bio = READ_ONCE(kiocb->private); 977 if (bio) 978 ret = bio_poll(bio, iob, flags); 979 rcu_read_unlock(); 980 981 return ret; 982} 983EXPORT_SYMBOL_GPL(iocb_bio_iopoll); 984 985void update_io_ticks(struct block_device *part, unsigned long now, bool end) 986{ 987 unsigned long stamp; 988again: 989 stamp = READ_ONCE(part->bd_stamp); 990 if (unlikely(time_after(now, stamp))) { 991 if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now))) 992 __part_stat_add(part, io_ticks, end ? now - stamp : 1); 993 } 994 if (part->bd_partno) { 995 part = bdev_whole(part); 996 goto again; 997 } 998} 999 1000unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op, 1001 unsigned long start_time) 1002{ 1003 part_stat_lock(); 1004 update_io_ticks(bdev, start_time, false); 1005 part_stat_local_inc(bdev, in_flight[op_is_write(op)]); 1006 part_stat_unlock(); 1007 1008 return start_time; 1009} 1010EXPORT_SYMBOL(bdev_start_io_acct); 1011 1012/** 1013 * bio_start_io_acct - start I/O accounting for bio based drivers 1014 * @bio: bio to start account for 1015 * 1016 * Returns the start time that should be passed back to bio_end_io_acct(). 1017 */ 1018unsigned long bio_start_io_acct(struct bio *bio) 1019{ 1020 return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies); 1021} 1022EXPORT_SYMBOL_GPL(bio_start_io_acct); 1023 1024void bdev_end_io_acct(struct block_device *bdev, enum req_op op, 1025 unsigned int sectors, unsigned long start_time) 1026{ 1027 const int sgrp = op_stat_group(op); 1028 unsigned long now = READ_ONCE(jiffies); 1029 unsigned long duration = now - start_time; 1030 1031 part_stat_lock(); 1032 update_io_ticks(bdev, now, true); 1033 part_stat_inc(bdev, ios[sgrp]); 1034 part_stat_add(bdev, sectors[sgrp], sectors); 1035 part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration)); 1036 part_stat_local_dec(bdev, in_flight[op_is_write(op)]); 1037 part_stat_unlock(); 1038} 1039EXPORT_SYMBOL(bdev_end_io_acct); 1040 1041void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, 1042 struct block_device *orig_bdev) 1043{ 1044 bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time); 1045} 1046EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped); 1047 1048/** 1049 * blk_lld_busy - Check if underlying low-level drivers of a device are busy 1050 * @q : the queue of the device being checked 1051 * 1052 * Description: 1053 * Check if underlying low-level drivers of a device are busy. 1054 * If the drivers want to export their busy state, they must set own 1055 * exporting function using blk_queue_lld_busy() first. 1056 * 1057 * Basically, this function is used only by request stacking drivers 1058 * to stop dispatching requests to underlying devices when underlying 1059 * devices are busy. This behavior helps more I/O merging on the queue 1060 * of the request stacking driver and prevents I/O throughput regression 1061 * on burst I/O load. 1062 * 1063 * Return: 1064 * 0 - Not busy (The request stacking driver should dispatch request) 1065 * 1 - Busy (The request stacking driver should stop dispatching request) 1066 */ 1067int blk_lld_busy(struct request_queue *q) 1068{ 1069 if (queue_is_mq(q) && q->mq_ops->busy) 1070 return q->mq_ops->busy(q); 1071 1072 return 0; 1073} 1074EXPORT_SYMBOL_GPL(blk_lld_busy); 1075 1076int kblockd_schedule_work(struct work_struct *work) 1077{ 1078 return queue_work(kblockd_workqueue, work); 1079} 1080EXPORT_SYMBOL(kblockd_schedule_work); 1081 1082int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, 1083 unsigned long delay) 1084{ 1085 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); 1086} 1087EXPORT_SYMBOL(kblockd_mod_delayed_work_on); 1088 1089void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) 1090{ 1091 struct task_struct *tsk = current; 1092 1093 /* 1094 * If this is a nested plug, don't actually assign it. 1095 */ 1096 if (tsk->plug) 1097 return; 1098 1099 plug->cur_ktime = 0; 1100 plug->mq_list = NULL; 1101 plug->cached_rq = NULL; 1102 plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); 1103 plug->rq_count = 0; 1104 plug->multiple_queues = false; 1105 plug->has_elevator = false; 1106 INIT_LIST_HEAD(&plug->cb_list); 1107 1108 /* 1109 * Store ordering should not be needed here, since a potential 1110 * preempt will imply a full memory barrier 1111 */ 1112 tsk->plug = plug; 1113} 1114 1115/** 1116 * blk_start_plug - initialize blk_plug and track it inside the task_struct 1117 * @plug: The &struct blk_plug that needs to be initialized 1118 * 1119 * Description: 1120 * blk_start_plug() indicates to the block layer an intent by the caller 1121 * to submit multiple I/O requests in a batch. The block layer may use 1122 * this hint to defer submitting I/Os from the caller until blk_finish_plug() 1123 * is called. However, the block layer may choose to submit requests 1124 * before a call to blk_finish_plug() if the number of queued I/Os 1125 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than 1126 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if 1127 * the task schedules (see below). 1128 * 1129 * Tracking blk_plug inside the task_struct will help with auto-flushing the 1130 * pending I/O should the task end up blocking between blk_start_plug() and 1131 * blk_finish_plug(). This is important from a performance perspective, but 1132 * also ensures that we don't deadlock. For instance, if the task is blocking 1133 * for a memory allocation, memory reclaim could end up wanting to free a 1134 * page belonging to that request that is currently residing in our private 1135 * plug. By flushing the pending I/O when the process goes to sleep, we avoid 1136 * this kind of deadlock. 1137 */ 1138void blk_start_plug(struct blk_plug *plug) 1139{ 1140 blk_start_plug_nr_ios(plug, 1); 1141} 1142EXPORT_SYMBOL(blk_start_plug); 1143 1144static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) 1145{ 1146 LIST_HEAD(callbacks); 1147 1148 while (!list_empty(&plug->cb_list)) { 1149 list_splice_init(&plug->cb_list, &callbacks); 1150 1151 while (!list_empty(&callbacks)) { 1152 struct blk_plug_cb *cb = list_first_entry(&callbacks, 1153 struct blk_plug_cb, 1154 list); 1155 list_del(&cb->list); 1156 cb->callback(cb, from_schedule); 1157 } 1158 } 1159} 1160 1161struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, 1162 int size) 1163{ 1164 struct blk_plug *plug = current->plug; 1165 struct blk_plug_cb *cb; 1166 1167 if (!plug) 1168 return NULL; 1169 1170 list_for_each_entry(cb, &plug->cb_list, list) 1171 if (cb->callback == unplug && cb->data == data) 1172 return cb; 1173 1174 /* Not currently on the callback list */ 1175 BUG_ON(size < sizeof(*cb)); 1176 cb = kzalloc(size, GFP_ATOMIC); 1177 if (cb) { 1178 cb->data = data; 1179 cb->callback = unplug; 1180 list_add(&cb->list, &plug->cb_list); 1181 } 1182 return cb; 1183} 1184EXPORT_SYMBOL(blk_check_plugged); 1185 1186void __blk_flush_plug(struct blk_plug *plug, bool from_schedule) 1187{ 1188 if (!list_empty(&plug->cb_list)) 1189 flush_plug_callbacks(plug, from_schedule); 1190 blk_mq_flush_plug_list(plug, from_schedule); 1191 /* 1192 * Unconditionally flush out cached requests, even if the unplug 1193 * event came from schedule. Since we know hold references to the 1194 * queue for cached requests, we don't want a blocked task holding 1195 * up a queue freeze/quiesce event. 1196 */ 1197 if (unlikely(!rq_list_empty(plug->cached_rq))) 1198 blk_mq_free_plug_rqs(plug); 1199 1200 plug->cur_ktime = 0; 1201 current->flags &= ~PF_BLOCK_TS; 1202} 1203 1204/** 1205 * blk_finish_plug - mark the end of a batch of submitted I/O 1206 * @plug: The &struct blk_plug passed to blk_start_plug() 1207 * 1208 * Description: 1209 * Indicate that a batch of I/O submissions is complete. This function 1210 * must be paired with an initial call to blk_start_plug(). The intent 1211 * is to allow the block layer to optimize I/O submission. See the 1212 * documentation for blk_start_plug() for more information. 1213 */ 1214void blk_finish_plug(struct blk_plug *plug) 1215{ 1216 if (plug == current->plug) { 1217 __blk_flush_plug(plug, false); 1218 current->plug = NULL; 1219 } 1220} 1221EXPORT_SYMBOL(blk_finish_plug); 1222 1223void blk_io_schedule(void) 1224{ 1225 /* Prevent hang_check timer from firing at us during very long I/O */ 1226 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; 1227 1228 if (timeout) 1229 io_schedule_timeout(timeout); 1230 else 1231 io_schedule(); 1232} 1233EXPORT_SYMBOL_GPL(blk_io_schedule); 1234 1235int __init blk_dev_init(void) 1236{ 1237 BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS)); 1238 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1239 sizeof_field(struct request, cmd_flags)); 1240 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1241 sizeof_field(struct bio, bi_opf)); 1242 1243 /* used for unplugging and affects IO latency/throughput - HIGHPRI */ 1244 kblockd_workqueue = alloc_workqueue("kblockd", 1245 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); 1246 if (!kblockd_workqueue) 1247 panic("Failed to create kblockd\n"); 1248 1249 blk_requestq_cachep = KMEM_CACHE(request_queue, SLAB_PANIC); 1250 1251 blk_debugfs_root = debugfs_create_dir("block", NULL); 1252 1253 return 0; 1254} 1255