1264 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 1991, 1992 Linus Torvalds4 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics5 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE6 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>7 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>8 * - July20009 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 200110 */11 12/*13 * This handles all read/write requests to block devices14 */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_POINTS45#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 allocation67 */68static struct kmem_cache *blk_requestq_cachep;69 70/*71 * Controlling structure to kblockd72 */73static struct workqueue_struct *kblockd_workqueue;74 75/**76 * blk_queue_flag_set - atomically set a queue flag77 * @flag: flag to be set78 * @q: request queue79 */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 flag88 * @flag: flag to be cleared89 * @q: request queue90 */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#define REQ_OP_NAME(name) [REQ_OP_##name] = #name98static const char *const blk_op_name[] = {99 REQ_OP_NAME(READ),100 REQ_OP_NAME(WRITE),101 REQ_OP_NAME(FLUSH),102 REQ_OP_NAME(DISCARD),103 REQ_OP_NAME(SECURE_ERASE),104 REQ_OP_NAME(ZONE_RESET),105 REQ_OP_NAME(ZONE_RESET_ALL),106 REQ_OP_NAME(ZONE_OPEN),107 REQ_OP_NAME(ZONE_CLOSE),108 REQ_OP_NAME(ZONE_FINISH),109 REQ_OP_NAME(ZONE_APPEND),110 REQ_OP_NAME(WRITE_ZEROES),111 REQ_OP_NAME(DRV_IN),112 REQ_OP_NAME(DRV_OUT),113};114#undef REQ_OP_NAME115 116/**117 * blk_op_str - Return string XXX in the REQ_OP_XXX.118 * @op: REQ_OP_XXX.119 *120 * Description: Centralize block layer function to convert REQ_OP_XXX into121 * string format. Useful in the debugging and tracing bio or request. For122 * invalid REQ_OP_XXX it returns string "UNKNOWN".123 */124inline const char *blk_op_str(enum req_op op)125{126 const char *op_str = "UNKNOWN";127 128 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])129 op_str = blk_op_name[op];130 131 return op_str;132}133EXPORT_SYMBOL_GPL(blk_op_str);134 135static const struct {136 int errno;137 const char *name;138} blk_errors[] = {139 [BLK_STS_OK] = { 0, "" },140 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },141 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },142 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },143 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },144 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },145 [BLK_STS_RESV_CONFLICT] = { -EBADE, "reservation conflict" },146 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },147 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },148 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },149 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },150 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },151 [BLK_STS_OFFLINE] = { -ENODEV, "device offline" },152 153 /* device mapper special case, should not leak out: */154 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },155 156 /* zone device specific errors */157 [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },158 [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },159 160 /* Command duration limit device-side timeout */161 [BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit exceeded" },162 163 [BLK_STS_INVAL] = { -EINVAL, "invalid" },164 165 /* everything else not covered above: */166 [BLK_STS_IOERR] = { -EIO, "I/O" },167};168 169blk_status_t errno_to_blk_status(int errno)170{171 int i;172 173 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {174 if (blk_errors[i].errno == errno)175 return (__force blk_status_t)i;176 }177 178 return BLK_STS_IOERR;179}180EXPORT_SYMBOL_GPL(errno_to_blk_status);181 182int blk_status_to_errno(blk_status_t status)183{184 int idx = (__force int)status;185 186 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))187 return -EIO;188 return blk_errors[idx].errno;189}190EXPORT_SYMBOL_GPL(blk_status_to_errno);191 192const char *blk_status_to_str(blk_status_t status)193{194 int idx = (__force int)status;195 196 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))197 return "<null>";198 return blk_errors[idx].name;199}200EXPORT_SYMBOL_GPL(blk_status_to_str);201 202/**203 * blk_sync_queue - cancel any pending callbacks on a queue204 * @q: the queue205 *206 * Description:207 * The block layer may perform asynchronous callback activity208 * on a queue, such as calling the unplug function after a timeout.209 * A block device may call blk_sync_queue to ensure that any210 * such activity is cancelled, thus allowing it to release resources211 * that the callbacks might use. The caller must already have made sure212 * that its ->submit_bio will not re-add plugging prior to calling213 * this function.214 *215 * This function does not cancel any asynchronous activity arising216 * out of elevator or throttling code. That would require elevator_exit()217 * and blkcg_exit_queue() to be called with queue lock initialized.218 *219 */220void blk_sync_queue(struct request_queue *q)221{222 del_timer_sync(&q->timeout);223 cancel_work_sync(&q->timeout_work);224}225EXPORT_SYMBOL(blk_sync_queue);226 227/**228 * blk_set_pm_only - increment pm_only counter229 * @q: request queue pointer230 */231void blk_set_pm_only(struct request_queue *q)232{233 atomic_inc(&q->pm_only);234}235EXPORT_SYMBOL_GPL(blk_set_pm_only);236 237void blk_clear_pm_only(struct request_queue *q)238{239 int pm_only;240 241 pm_only = atomic_dec_return(&q->pm_only);242 WARN_ON_ONCE(pm_only < 0);243 if (pm_only == 0)244 wake_up_all(&q->mq_freeze_wq);245}246EXPORT_SYMBOL_GPL(blk_clear_pm_only);247 248static void blk_free_queue_rcu(struct rcu_head *rcu_head)249{250 struct request_queue *q = container_of(rcu_head,251 struct request_queue, rcu_head);252 253 percpu_ref_exit(&q->q_usage_counter);254 kmem_cache_free(blk_requestq_cachep, q);255}256 257static void blk_free_queue(struct request_queue *q)258{259 blk_free_queue_stats(q->stats);260 if (queue_is_mq(q))261 blk_mq_release(q);262 263 ida_free(&blk_queue_ida, q->id);264 call_rcu(&q->rcu_head, blk_free_queue_rcu);265}266 267/**268 * blk_put_queue - decrement the request_queue refcount269 * @q: the request_queue structure to decrement the refcount for270 *271 * Decrements the refcount of the request_queue and free it when the refcount272 * reaches 0.273 */274void blk_put_queue(struct request_queue *q)275{276 if (refcount_dec_and_test(&q->refs))277 blk_free_queue(q);278}279EXPORT_SYMBOL(blk_put_queue);280 281void blk_queue_start_drain(struct request_queue *q)282{283 /*284 * When queue DYING flag is set, we need to block new req285 * entering queue, so we call blk_freeze_queue_start() to286 * prevent I/O from crossing blk_queue_enter().287 */288 blk_freeze_queue_start(q);289 if (queue_is_mq(q))290 blk_mq_wake_waiters(q);291 /* Make blk_queue_enter() reexamine the DYING flag. */292 wake_up_all(&q->mq_freeze_wq);293}294 295/**296 * blk_queue_enter() - try to increase q->q_usage_counter297 * @q: request queue pointer298 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM299 */300int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)301{302 const bool pm = flags & BLK_MQ_REQ_PM;303 304 while (!blk_try_enter_queue(q, pm)) {305 if (flags & BLK_MQ_REQ_NOWAIT)306 return -EAGAIN;307 308 /*309 * read pair of barrier in blk_freeze_queue_start(), we need to310 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and311 * reading .mq_freeze_depth or queue dying flag, otherwise the312 * following wait may never return if the two reads are313 * reordered.314 */315 smp_rmb();316 wait_event(q->mq_freeze_wq,317 (!q->mq_freeze_depth &&318 blk_pm_resume_queue(pm, q)) ||319 blk_queue_dying(q));320 if (blk_queue_dying(q))321 return -ENODEV;322 }323 324 return 0;325}326 327int __bio_queue_enter(struct request_queue *q, struct bio *bio)328{329 while (!blk_try_enter_queue(q, false)) {330 struct gendisk *disk = bio->bi_bdev->bd_disk;331 332 if (bio->bi_opf & REQ_NOWAIT) {333 if (test_bit(GD_DEAD, &disk->state))334 goto dead;335 bio_wouldblock_error(bio);336 return -EAGAIN;337 }338 339 /*340 * read pair of barrier in blk_freeze_queue_start(), we need to341 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and342 * reading .mq_freeze_depth or queue dying flag, otherwise the343 * following wait may never return if the two reads are344 * reordered.345 */346 smp_rmb();347 wait_event(q->mq_freeze_wq,348 (!q->mq_freeze_depth &&349 blk_pm_resume_queue(false, q)) ||350 test_bit(GD_DEAD, &disk->state));351 if (test_bit(GD_DEAD, &disk->state))352 goto dead;353 }354 355 return 0;356dead:357 bio_io_error(bio);358 return -ENODEV;359}360 361void blk_queue_exit(struct request_queue *q)362{363 percpu_ref_put(&q->q_usage_counter);364}365 366static void blk_queue_usage_counter_release(struct percpu_ref *ref)367{368 struct request_queue *q =369 container_of(ref, struct request_queue, q_usage_counter);370 371 wake_up_all(&q->mq_freeze_wq);372}373 374static void blk_rq_timed_out_timer(struct timer_list *t)375{376 struct request_queue *q = from_timer(q, t, timeout);377 378 kblockd_schedule_work(&q->timeout_work);379}380 381static void blk_timeout_work(struct work_struct *work)382{383}384 385struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id)386{387 struct request_queue *q;388 int error;389 390 q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO,391 node_id);392 if (!q)393 return ERR_PTR(-ENOMEM);394 395 q->last_merge = NULL;396 397 q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL);398 if (q->id < 0) {399 error = q->id;400 goto fail_q;401 }402 403 q->stats = blk_alloc_queue_stats();404 if (!q->stats) {405 error = -ENOMEM;406 goto fail_id;407 }408 409 error = blk_set_default_limits(lim);410 if (error)411 goto fail_stats;412 q->limits = *lim;413 414 q->node = node_id;415 416 atomic_set(&q->nr_active_requests_shared_tags, 0);417 418 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);419 INIT_WORK(&q->timeout_work, blk_timeout_work);420 INIT_LIST_HEAD(&q->icq_list);421 422 refcount_set(&q->refs, 1);423 mutex_init(&q->debugfs_mutex);424 mutex_init(&q->sysfs_lock);425 mutex_init(&q->sysfs_dir_lock);426 mutex_init(&q->limits_lock);427 mutex_init(&q->rq_qos_mutex);428 spin_lock_init(&q->queue_lock);429 430 init_waitqueue_head(&q->mq_freeze_wq);431 mutex_init(&q->mq_freeze_lock);432 433 blkg_init_queue(q);434 435 /*436 * Init percpu_ref in atomic mode so that it's faster to shutdown.437 * See blk_register_queue() for details.438 */439 error = percpu_ref_init(&q->q_usage_counter,440 blk_queue_usage_counter_release,441 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);442 if (error)443 goto fail_stats;444 445 q->nr_requests = BLKDEV_DEFAULT_RQ;446 447 return q;448 449fail_stats:450 blk_free_queue_stats(q->stats);451fail_id:452 ida_free(&blk_queue_ida, q->id);453fail_q:454 kmem_cache_free(blk_requestq_cachep, q);455 return ERR_PTR(error);456}457 458/**459 * blk_get_queue - increment the request_queue refcount460 * @q: the request_queue structure to increment the refcount for461 *462 * Increment the refcount of the request_queue kobject.463 *464 * Context: Any context.465 */466bool blk_get_queue(struct request_queue *q)467{468 if (unlikely(blk_queue_dying(q)))469 return false;470 refcount_inc(&q->refs);471 return true;472}473EXPORT_SYMBOL(blk_get_queue);474 475#ifdef CONFIG_FAIL_MAKE_REQUEST476 477static DECLARE_FAULT_ATTR(fail_make_request);478 479static int __init setup_fail_make_request(char *str)480{481 return setup_fault_attr(&fail_make_request, str);482}483__setup("fail_make_request=", setup_fail_make_request);484 485bool should_fail_request(struct block_device *part, unsigned int bytes)486{487 return bdev_test_flag(part, BD_MAKE_IT_FAIL) &&488 should_fail(&fail_make_request, bytes);489}490 491static int __init fail_make_request_debugfs(void)492{493 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",494 NULL, &fail_make_request);495 496 return PTR_ERR_OR_ZERO(dir);497}498 499late_initcall(fail_make_request_debugfs);500#endif /* CONFIG_FAIL_MAKE_REQUEST */501 502static inline void bio_check_ro(struct bio *bio)503{504 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {505 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))506 return;507 508 if (bdev_test_flag(bio->bi_bdev, BD_RO_WARNED))509 return;510 511 bdev_set_flag(bio->bi_bdev, BD_RO_WARNED);512 513 /*514 * Use ioctl to set underlying disk of raid/dm to read-only515 * will trigger this.516 */517 pr_warn("Trying to write to read-only block-device %pg\n",518 bio->bi_bdev);519 }520}521 522static noinline int should_fail_bio(struct bio *bio)523{524 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))525 return -EIO;526 return 0;527}528ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);529 530/*531 * Check whether this bio extends beyond the end of the device or partition.532 * This may well happen - the kernel calls bread() without checking the size of533 * the device, e.g., when mounting a file system.534 */535static inline int bio_check_eod(struct bio *bio)536{537 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);538 unsigned int nr_sectors = bio_sectors(bio);539 540 if (nr_sectors &&541 (nr_sectors > maxsector ||542 bio->bi_iter.bi_sector > maxsector - nr_sectors)) {543 pr_info_ratelimited("%s: attempt to access beyond end of device\n"544 "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n",545 current->comm, bio->bi_bdev, bio->bi_opf,546 bio->bi_iter.bi_sector, nr_sectors, maxsector);547 return -EIO;548 }549 return 0;550}551 552/*553 * Remap block n of partition p to block n+start(p) of the disk.554 */555static int blk_partition_remap(struct bio *bio)556{557 struct block_device *p = bio->bi_bdev;558 559 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))560 return -EIO;561 if (bio_sectors(bio)) {562 bio->bi_iter.bi_sector += p->bd_start_sect;563 trace_block_bio_remap(bio, p->bd_dev,564 bio->bi_iter.bi_sector -565 p->bd_start_sect);566 }567 bio_set_flag(bio, BIO_REMAPPED);568 return 0;569}570 571/*572 * Check write append to a zoned block device.573 */574static inline blk_status_t blk_check_zone_append(struct request_queue *q,575 struct bio *bio)576{577 int nr_sectors = bio_sectors(bio);578 579 /* Only applicable to zoned block devices */580 if (!bdev_is_zoned(bio->bi_bdev))581 return BLK_STS_NOTSUPP;582 583 /* The bio sector must point to the start of a sequential zone */584 if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector))585 return BLK_STS_IOERR;586 587 /*588 * Not allowed to cross zone boundaries. Otherwise, the BIO will be589 * split and could result in non-contiguous sectors being written in590 * different zones.591 */592 if (nr_sectors > q->limits.chunk_sectors)593 return BLK_STS_IOERR;594 595 /* Make sure the BIO is small enough and will not get split */596 if (nr_sectors > queue_max_zone_append_sectors(q))597 return BLK_STS_IOERR;598 599 bio->bi_opf |= REQ_NOMERGE;600 601 return BLK_STS_OK;602}603 604static void __submit_bio(struct bio *bio)605{606 /* If plug is not used, add new plug here to cache nsecs time. */607 struct blk_plug plug;608 609 if (unlikely(!blk_crypto_bio_prep(&bio)))610 return;611 612 blk_start_plug(&plug);613 614 if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO)) {615 blk_mq_submit_bio(bio);616 } else if (likely(bio_queue_enter(bio) == 0)) {617 struct gendisk *disk = bio->bi_bdev->bd_disk;618 619 disk->fops->submit_bio(bio);620 blk_queue_exit(disk->queue);621 }622 623 blk_finish_plug(&plug);624}625 626/*627 * The loop in this function may be a bit non-obvious, and so deserves some628 * explanation:629 *630 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure631 * that), so we have a list with a single bio.632 * - We pretend that we have just taken it off a longer list, so we assign633 * bio_list to a pointer to the bio_list_on_stack, thus initialising the634 * bio_list of new bios to be added. ->submit_bio() may indeed add some more635 * bios through a recursive call to submit_bio_noacct. If it did, we find a636 * non-NULL value in bio_list and re-enter the loop from the top.637 * - In this case we really did just take the bio of the top of the list (no638 * pretending) and so remove it from bio_list, and call into ->submit_bio()639 * again.640 *641 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.642 * bio_list_on_stack[1] contains bios that were submitted before the current643 * ->submit_bio, but that haven't been processed yet.644 */645static void __submit_bio_noacct(struct bio *bio)646{647 struct bio_list bio_list_on_stack[2];648 649 BUG_ON(bio->bi_next);650 651 bio_list_init(&bio_list_on_stack[0]);652 current->bio_list = bio_list_on_stack;653 654 do {655 struct request_queue *q = bdev_get_queue(bio->bi_bdev);656 struct bio_list lower, same;657 658 /*659 * Create a fresh bio_list for all subordinate requests.660 */661 bio_list_on_stack[1] = bio_list_on_stack[0];662 bio_list_init(&bio_list_on_stack[0]);663 664 __submit_bio(bio);665 666 /*667 * Sort new bios into those for a lower level and those for the668 * same level.669 */670 bio_list_init(&lower);671 bio_list_init(&same);672 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)673 if (q == bdev_get_queue(bio->bi_bdev))674 bio_list_add(&same, bio);675 else676 bio_list_add(&lower, bio);677 678 /*679 * Now assemble so we handle the lowest level first.680 */681 bio_list_merge(&bio_list_on_stack[0], &lower);682 bio_list_merge(&bio_list_on_stack[0], &same);683 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);684 } while ((bio = bio_list_pop(&bio_list_on_stack[0])));685 686 current->bio_list = NULL;687}688 689static void __submit_bio_noacct_mq(struct bio *bio)690{691 struct bio_list bio_list[2] = { };692 693 current->bio_list = bio_list;694 695 do {696 __submit_bio(bio);697 } while ((bio = bio_list_pop(&bio_list[0])));698 699 current->bio_list = NULL;700}701 702void submit_bio_noacct_nocheck(struct bio *bio)703{704 blk_cgroup_bio_start(bio);705 blkcg_bio_issue_init(bio);706 707 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {708 trace_block_bio_queue(bio);709 /*710 * Now that enqueuing has been traced, we need to trace711 * completion as well.712 */713 bio_set_flag(bio, BIO_TRACE_COMPLETION);714 }715 716 /*717 * We only want one ->submit_bio to be active at a time, else stack718 * usage with stacked devices could be a problem. Use current->bio_list719 * to collect a list of requests submited by a ->submit_bio method while720 * it is active, and then process them after it returned.721 */722 if (current->bio_list)723 bio_list_add(¤t->bio_list[0], bio);724 else if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO))725 __submit_bio_noacct_mq(bio);726 else727 __submit_bio_noacct(bio);728}729 730static blk_status_t blk_validate_atomic_write_op_size(struct request_queue *q,731 struct bio *bio)732{733 if (bio->bi_iter.bi_size > queue_atomic_write_unit_max_bytes(q))734 return BLK_STS_INVAL;735 736 if (bio->bi_iter.bi_size % queue_atomic_write_unit_min_bytes(q))737 return BLK_STS_INVAL;738 739 return BLK_STS_OK;740}741 742/**743 * submit_bio_noacct - re-submit a bio to the block device layer for I/O744 * @bio: The bio describing the location in memory and on the device.745 *746 * This is a version of submit_bio() that shall only be used for I/O that is747 * resubmitted to lower level drivers by stacking block drivers. All file748 * systems and other upper level users of the block layer should use749 * submit_bio() instead.750 */751void submit_bio_noacct(struct bio *bio)752{753 struct block_device *bdev = bio->bi_bdev;754 struct request_queue *q = bdev_get_queue(bdev);755 blk_status_t status = BLK_STS_IOERR;756 757 might_sleep();758 759 /*760 * For a REQ_NOWAIT based request, return -EOPNOTSUPP761 * if queue does not support NOWAIT.762 */763 if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev))764 goto not_supported;765 766 if (should_fail_bio(bio))767 goto end_io;768 bio_check_ro(bio);769 if (!bio_flagged(bio, BIO_REMAPPED)) {770 if (unlikely(bio_check_eod(bio)))771 goto end_io;772 if (bdev_is_partition(bdev) &&773 unlikely(blk_partition_remap(bio)))774 goto end_io;775 }776 777 /*778 * Filter flush bio's early so that bio based drivers without flush779 * support don't have to worry about them.780 */781 if (op_is_flush(bio->bi_opf)) {782 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE &&783 bio_op(bio) != REQ_OP_ZONE_APPEND))784 goto end_io;785 if (!bdev_write_cache(bdev)) {786 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);787 if (!bio_sectors(bio)) {788 status = BLK_STS_OK;789 goto end_io;790 }791 }792 }793 794 if (!(q->limits.features & BLK_FEAT_POLL) &&795 (bio->bi_opf & REQ_POLLED)) {796 bio_clear_polled(bio);797 goto not_supported;798 }799 800 switch (bio_op(bio)) {801 case REQ_OP_READ:802 break;803 case REQ_OP_WRITE:804 if (bio->bi_opf & REQ_ATOMIC) {805 status = blk_validate_atomic_write_op_size(q, bio);806 if (status != BLK_STS_OK)807 goto end_io;808 }809 break;810 case REQ_OP_FLUSH:811 /*812 * REQ_OP_FLUSH can't be submitted through bios, it is only813 * synthetized in struct request by the flush state machine.814 */815 goto not_supported;816 case REQ_OP_DISCARD:817 if (!bdev_max_discard_sectors(bdev))818 goto not_supported;819 break;820 case REQ_OP_SECURE_ERASE:821 if (!bdev_max_secure_erase_sectors(bdev))822 goto not_supported;823 break;824 case REQ_OP_ZONE_APPEND:825 status = blk_check_zone_append(q, bio);826 if (status != BLK_STS_OK)827 goto end_io;828 break;829 case REQ_OP_WRITE_ZEROES:830 if (!q->limits.max_write_zeroes_sectors)831 goto not_supported;832 break;833 case REQ_OP_ZONE_RESET:834 case REQ_OP_ZONE_OPEN:835 case REQ_OP_ZONE_CLOSE:836 case REQ_OP_ZONE_FINISH:837 case REQ_OP_ZONE_RESET_ALL:838 if (!bdev_is_zoned(bio->bi_bdev))839 goto not_supported;840 break;841 case REQ_OP_DRV_IN:842 case REQ_OP_DRV_OUT:843 /*844 * Driver private operations are only used with passthrough845 * requests.846 */847 fallthrough;848 default:849 goto not_supported;850 }851 852 if (blk_throtl_bio(bio))853 return;854 submit_bio_noacct_nocheck(bio);855 return;856 857not_supported:858 status = BLK_STS_NOTSUPP;859end_io:860 bio->bi_status = status;861 bio_endio(bio);862}863EXPORT_SYMBOL(submit_bio_noacct);864 865static void bio_set_ioprio(struct bio *bio)866{867 /* Nobody set ioprio so far? Initialize it based on task's nice value */868 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)869 bio->bi_ioprio = get_current_ioprio();870 blkcg_set_ioprio(bio);871}872 873/**874 * submit_bio - submit a bio to the block device layer for I/O875 * @bio: The &struct bio which describes the I/O876 *877 * submit_bio() is used to submit I/O requests to block devices. It is passed a878 * fully set up &struct bio that describes the I/O that needs to be done. The879 * bio will be send to the device described by the bi_bdev field.880 *881 * The success/failure status of the request, along with notification of882 * completion, is delivered asynchronously through the ->bi_end_io() callback883 * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has884 * been called.885 */886void submit_bio(struct bio *bio)887{888 if (bio_op(bio) == REQ_OP_READ) {889 task_io_account_read(bio->bi_iter.bi_size);890 count_vm_events(PGPGIN, bio_sectors(bio));891 } else if (bio_op(bio) == REQ_OP_WRITE) {892 count_vm_events(PGPGOUT, bio_sectors(bio));893 }894 895 bio_set_ioprio(bio);896 submit_bio_noacct(bio);897}898EXPORT_SYMBOL(submit_bio);899 900/**901 * bio_poll - poll for BIO completions902 * @bio: bio to poll for903 * @iob: batches of IO904 * @flags: BLK_POLL_* flags that control the behavior905 *906 * Poll for completions on queue associated with the bio. Returns number of907 * completed entries found.908 *909 * Note: the caller must either be the context that submitted @bio, or910 * be in a RCU critical section to prevent freeing of @bio.911 */912int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)913{914 blk_qc_t cookie = READ_ONCE(bio->bi_cookie);915 struct block_device *bdev;916 struct request_queue *q;917 int ret = 0;918 919 bdev = READ_ONCE(bio->bi_bdev);920 if (!bdev)921 return 0;922 923 q = bdev_get_queue(bdev);924 if (cookie == BLK_QC_T_NONE || !(q->limits.features & BLK_FEAT_POLL))925 return 0;926 927 blk_flush_plug(current->plug, false);928 929 /*930 * We need to be able to enter a frozen queue, similar to how931 * timeouts also need to do that. If that is blocked, then we can932 * have pending IO when a queue freeze is started, and then the933 * wait for the freeze to finish will wait for polled requests to934 * timeout as the poller is preventer from entering the queue and935 * completing them. As long as we prevent new IO from being queued,936 * that should be all that matters.937 */938 if (!percpu_ref_tryget(&q->q_usage_counter))939 return 0;940 if (queue_is_mq(q)) {941 ret = blk_mq_poll(q, cookie, iob, flags);942 } else {943 struct gendisk *disk = q->disk;944 945 if (disk && disk->fops->poll_bio)946 ret = disk->fops->poll_bio(bio, iob, flags);947 }948 blk_queue_exit(q);949 return ret;950}951EXPORT_SYMBOL_GPL(bio_poll);952 953/*954 * Helper to implement file_operations.iopoll. Requires the bio to be stored955 * in iocb->private, and cleared before freeing the bio.956 */957int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,958 unsigned int flags)959{960 struct bio *bio;961 int ret = 0;962 963 /*964 * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can965 * point to a freshly allocated bio at this point. If that happens966 * we have a few cases to consider:967 *968 * 1) the bio is beeing initialized and bi_bdev is NULL. We can just969 * simply nothing in this case970 * 2) the bio points to a not poll enabled device. bio_poll will catch971 * this and return 0972 * 3) the bio points to a poll capable device, including but not973 * limited to the one that the original bio pointed to. In this974 * case we will call into the actual poll method and poll for I/O,975 * even if we don't need to, but it won't cause harm either.976 *977 * For cases 2) and 3) above the RCU grace period ensures that bi_bdev978 * is still allocated. Because partitions hold a reference to the whole979 * device bdev and thus disk, the disk is also still valid. Grabbing980 * a reference to the queue in bio_poll() ensures the hctxs and requests981 * are still valid as well.982 */983 rcu_read_lock();984 bio = READ_ONCE(kiocb->private);985 if (bio)986 ret = bio_poll(bio, iob, flags);987 rcu_read_unlock();988 989 return ret;990}991EXPORT_SYMBOL_GPL(iocb_bio_iopoll);992 993void update_io_ticks(struct block_device *part, unsigned long now, bool end)994{995 unsigned long stamp;996again:997 stamp = READ_ONCE(part->bd_stamp);998 if (unlikely(time_after(now, stamp)) &&999 likely(try_cmpxchg(&part->bd_stamp, &stamp, now)) &&1000 (end || part_in_flight(part)))1001 __part_stat_add(part, io_ticks, now - stamp);1002 1003 if (bdev_is_partition(part)) {1004 part = bdev_whole(part);1005 goto again;1006 }1007}1008 1009unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,1010 unsigned long start_time)1011{1012 part_stat_lock();1013 update_io_ticks(bdev, start_time, false);1014 part_stat_local_inc(bdev, in_flight[op_is_write(op)]);1015 part_stat_unlock();1016 1017 return start_time;1018}1019EXPORT_SYMBOL(bdev_start_io_acct);1020 1021/**1022 * bio_start_io_acct - start I/O accounting for bio based drivers1023 * @bio: bio to start account for1024 *1025 * Returns the start time that should be passed back to bio_end_io_acct().1026 */1027unsigned long bio_start_io_acct(struct bio *bio)1028{1029 return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies);1030}1031EXPORT_SYMBOL_GPL(bio_start_io_acct);1032 1033void bdev_end_io_acct(struct block_device *bdev, enum req_op op,1034 unsigned int sectors, unsigned long start_time)1035{1036 const int sgrp = op_stat_group(op);1037 unsigned long now = READ_ONCE(jiffies);1038 unsigned long duration = now - start_time;1039 1040 part_stat_lock();1041 update_io_ticks(bdev, now, true);1042 part_stat_inc(bdev, ios[sgrp]);1043 part_stat_add(bdev, sectors[sgrp], sectors);1044 part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));1045 part_stat_local_dec(bdev, in_flight[op_is_write(op)]);1046 part_stat_unlock();1047}1048EXPORT_SYMBOL(bdev_end_io_acct);1049 1050void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,1051 struct block_device *orig_bdev)1052{1053 bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time);1054}1055EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);1056 1057/**1058 * blk_lld_busy - Check if underlying low-level drivers of a device are busy1059 * @q : the queue of the device being checked1060 *1061 * Description:1062 * Check if underlying low-level drivers of a device are busy.1063 * If the drivers want to export their busy state, they must set own1064 * exporting function using blk_queue_lld_busy() first.1065 *1066 * Basically, this function is used only by request stacking drivers1067 * to stop dispatching requests to underlying devices when underlying1068 * devices are busy. This behavior helps more I/O merging on the queue1069 * of the request stacking driver and prevents I/O throughput regression1070 * on burst I/O load.1071 *1072 * Return:1073 * 0 - Not busy (The request stacking driver should dispatch request)1074 * 1 - Busy (The request stacking driver should stop dispatching request)1075 */1076int blk_lld_busy(struct request_queue *q)1077{1078 if (queue_is_mq(q) && q->mq_ops->busy)1079 return q->mq_ops->busy(q);1080 1081 return 0;1082}1083EXPORT_SYMBOL_GPL(blk_lld_busy);1084 1085int kblockd_schedule_work(struct work_struct *work)1086{1087 return queue_work(kblockd_workqueue, work);1088}1089EXPORT_SYMBOL(kblockd_schedule_work);1090 1091int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,1092 unsigned long delay)1093{1094 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);1095}1096EXPORT_SYMBOL(kblockd_mod_delayed_work_on);1097 1098void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios)1099{1100 struct task_struct *tsk = current;1101 1102 /*1103 * If this is a nested plug, don't actually assign it.1104 */1105 if (tsk->plug)1106 return;1107 1108 plug->cur_ktime = 0;1109 plug->mq_list = NULL;1110 plug->cached_rq = NULL;1111 plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT);1112 plug->rq_count = 0;1113 plug->multiple_queues = false;1114 plug->has_elevator = false;1115 INIT_LIST_HEAD(&plug->cb_list);1116 1117 /*1118 * Store ordering should not be needed here, since a potential1119 * preempt will imply a full memory barrier1120 */1121 tsk->plug = plug;1122}1123 1124/**1125 * blk_start_plug - initialize blk_plug and track it inside the task_struct1126 * @plug: The &struct blk_plug that needs to be initialized1127 *1128 * Description:1129 * blk_start_plug() indicates to the block layer an intent by the caller1130 * to submit multiple I/O requests in a batch. The block layer may use1131 * this hint to defer submitting I/Os from the caller until blk_finish_plug()1132 * is called. However, the block layer may choose to submit requests1133 * before a call to blk_finish_plug() if the number of queued I/Os1134 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than1135 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if1136 * the task schedules (see below).1137 *1138 * Tracking blk_plug inside the task_struct will help with auto-flushing the1139 * pending I/O should the task end up blocking between blk_start_plug() and1140 * blk_finish_plug(). This is important from a performance perspective, but1141 * also ensures that we don't deadlock. For instance, if the task is blocking1142 * for a memory allocation, memory reclaim could end up wanting to free a1143 * page belonging to that request that is currently residing in our private1144 * plug. By flushing the pending I/O when the process goes to sleep, we avoid1145 * this kind of deadlock.1146 */1147void blk_start_plug(struct blk_plug *plug)1148{1149 blk_start_plug_nr_ios(plug, 1);1150}1151EXPORT_SYMBOL(blk_start_plug);1152 1153static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)1154{1155 LIST_HEAD(callbacks);1156 1157 while (!list_empty(&plug->cb_list)) {1158 list_splice_init(&plug->cb_list, &callbacks);1159 1160 while (!list_empty(&callbacks)) {1161 struct blk_plug_cb *cb = list_first_entry(&callbacks,1162 struct blk_plug_cb,1163 list);1164 list_del(&cb->list);1165 cb->callback(cb, from_schedule);1166 }1167 }1168}1169 1170struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,1171 int size)1172{1173 struct blk_plug *plug = current->plug;1174 struct blk_plug_cb *cb;1175 1176 if (!plug)1177 return NULL;1178 1179 list_for_each_entry(cb, &plug->cb_list, list)1180 if (cb->callback == unplug && cb->data == data)1181 return cb;1182 1183 /* Not currently on the callback list */1184 BUG_ON(size < sizeof(*cb));1185 cb = kzalloc(size, GFP_ATOMIC);1186 if (cb) {1187 cb->data = data;1188 cb->callback = unplug;1189 list_add(&cb->list, &plug->cb_list);1190 }1191 return cb;1192}1193EXPORT_SYMBOL(blk_check_plugged);1194 1195void __blk_flush_plug(struct blk_plug *plug, bool from_schedule)1196{1197 if (!list_empty(&plug->cb_list))1198 flush_plug_callbacks(plug, from_schedule);1199 blk_mq_flush_plug_list(plug, from_schedule);1200 /*1201 * Unconditionally flush out cached requests, even if the unplug1202 * event came from schedule. Since we know hold references to the1203 * queue for cached requests, we don't want a blocked task holding1204 * up a queue freeze/quiesce event.1205 */1206 if (unlikely(!rq_list_empty(plug->cached_rq)))1207 blk_mq_free_plug_rqs(plug);1208 1209 plug->cur_ktime = 0;1210 current->flags &= ~PF_BLOCK_TS;1211}1212 1213/**1214 * blk_finish_plug - mark the end of a batch of submitted I/O1215 * @plug: The &struct blk_plug passed to blk_start_plug()1216 *1217 * Description:1218 * Indicate that a batch of I/O submissions is complete. This function1219 * must be paired with an initial call to blk_start_plug(). The intent1220 * is to allow the block layer to optimize I/O submission. See the1221 * documentation for blk_start_plug() for more information.1222 */1223void blk_finish_plug(struct blk_plug *plug)1224{1225 if (plug == current->plug) {1226 __blk_flush_plug(plug, false);1227 current->plug = NULL;1228 }1229}1230EXPORT_SYMBOL(blk_finish_plug);1231 1232void blk_io_schedule(void)1233{1234 /* Prevent hang_check timer from firing at us during very long I/O */1235 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;1236 1237 if (timeout)1238 io_schedule_timeout(timeout);1239 else1240 io_schedule();1241}1242EXPORT_SYMBOL_GPL(blk_io_schedule);1243 1244int __init blk_dev_init(void)1245{1246 BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS));1247 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *1248 sizeof_field(struct request, cmd_flags));1249 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *1250 sizeof_field(struct bio, bi_opf));1251 1252 /* used for unplugging and affects IO latency/throughput - HIGHPRI */1253 kblockd_workqueue = alloc_workqueue("kblockd",1254 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);1255 if (!kblockd_workqueue)1256 panic("Failed to create kblockd\n");1257 1258 blk_requestq_cachep = KMEM_CACHE(request_queue, SLAB_PANIC);1259 1260 blk_debugfs_root = debugfs_create_dir("block", NULL);1261 1262 return 0;1263}1264