1 // SPDX-License-Identifier: GPL-2.0
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>
9 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
13 * This handles all read/write requests to block devices
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>
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>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/block.h>
48 #include "blk-mq-sched.h"
50 #include "blk-cgroup.h"
51 #include "blk-throttle.h"
52 #include "blk-ioprio.h"
54 struct dentry *blk_debugfs_root;
56 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
57 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
58 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
59 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
60 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
61 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
63 static DEFINE_IDA(blk_queue_ida);
66 * For queue allocation
68 static struct kmem_cache *blk_requestq_cachep;
71 * Controlling structure to kblockd
73 static struct workqueue_struct *kblockd_workqueue;
76 * blk_queue_flag_set - atomically set a queue flag
77 * @flag: flag to be set
80 void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
82 set_bit(flag, &q->queue_flags);
84 EXPORT_SYMBOL(blk_queue_flag_set);
87 * blk_queue_flag_clear - atomically clear a queue flag
88 * @flag: flag to be cleared
91 void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
93 clear_bit(flag, &q->queue_flags);
95 EXPORT_SYMBOL(blk_queue_flag_clear);
98 * blk_queue_flag_test_and_set - atomically test and set a queue flag
99 * @flag: flag to be set
102 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
103 * the flag was already set.
105 bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
107 return test_and_set_bit(flag, &q->queue_flags);
109 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
111 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
112 static const char *const blk_op_name[] = {
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),
126 REQ_OP_NAME(DRV_OUT),
131 * blk_op_str - Return string XXX in the REQ_OP_XXX.
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".
138 inline const char *blk_op_str(enum req_op op)
140 const char *op_str = "UNKNOWN";
142 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
143 op_str = blk_op_name[op];
147 EXPORT_SYMBOL_GPL(blk_op_str);
149 static const struct {
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" },
167 /* device mapper special case, should not leak out: */
168 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
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" },
174 /* Command duration limit device-side timeout */
175 [BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit exceeded" },
177 /* everything else not covered above: */
178 [BLK_STS_IOERR] = { -EIO, "I/O" },
181 blk_status_t errno_to_blk_status(int errno)
185 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
186 if (blk_errors[i].errno == errno)
187 return (__force blk_status_t)i;
190 return BLK_STS_IOERR;
192 EXPORT_SYMBOL_GPL(errno_to_blk_status);
194 int blk_status_to_errno(blk_status_t status)
196 int idx = (__force int)status;
198 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
200 return blk_errors[idx].errno;
202 EXPORT_SYMBOL_GPL(blk_status_to_errno);
204 const char *blk_status_to_str(blk_status_t status)
206 int idx = (__force int)status;
208 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
210 return blk_errors[idx].name;
212 EXPORT_SYMBOL_GPL(blk_status_to_str);
215 * blk_sync_queue - cancel any pending callbacks on a queue
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
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.
232 void blk_sync_queue(struct request_queue *q)
234 del_timer_sync(&q->timeout);
235 cancel_work_sync(&q->timeout_work);
237 EXPORT_SYMBOL(blk_sync_queue);
240 * blk_set_pm_only - increment pm_only counter
241 * @q: request queue pointer
243 void blk_set_pm_only(struct request_queue *q)
245 atomic_inc(&q->pm_only);
247 EXPORT_SYMBOL_GPL(blk_set_pm_only);
249 void blk_clear_pm_only(struct request_queue *q)
253 pm_only = atomic_dec_return(&q->pm_only);
254 WARN_ON_ONCE(pm_only < 0);
256 wake_up_all(&q->mq_freeze_wq);
258 EXPORT_SYMBOL_GPL(blk_clear_pm_only);
260 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
262 struct request_queue *q = container_of(rcu_head,
263 struct request_queue, rcu_head);
265 percpu_ref_exit(&q->q_usage_counter);
266 kmem_cache_free(blk_requestq_cachep, q);
269 static void blk_free_queue(struct request_queue *q)
271 blk_free_queue_stats(q->stats);
275 ida_free(&blk_queue_ida, q->id);
276 call_rcu(&q->rcu_head, blk_free_queue_rcu);
280 * blk_put_queue - decrement the request_queue refcount
281 * @q: the request_queue structure to decrement the refcount for
283 * Decrements the refcount of the request_queue and free it when the refcount
286 void blk_put_queue(struct request_queue *q)
288 if (refcount_dec_and_test(&q->refs))
291 EXPORT_SYMBOL(blk_put_queue);
293 void blk_queue_start_drain(struct request_queue *q)
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().
300 blk_freeze_queue_start(q);
302 blk_mq_wake_waiters(q);
303 /* Make blk_queue_enter() reexamine the DYING flag. */
304 wake_up_all(&q->mq_freeze_wq);
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
312 int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
314 const bool pm = flags & BLK_MQ_REQ_PM;
316 while (!blk_try_enter_queue(q, pm)) {
317 if (flags & BLK_MQ_REQ_NOWAIT)
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
328 wait_event(q->mq_freeze_wq,
329 (!q->mq_freeze_depth &&
330 blk_pm_resume_queue(pm, q)) ||
332 if (blk_queue_dying(q))
339 int __bio_queue_enter(struct request_queue *q, struct bio *bio)
341 while (!blk_try_enter_queue(q, false)) {
342 struct gendisk *disk = bio->bi_bdev->bd_disk;
344 if (bio->bi_opf & REQ_NOWAIT) {
345 if (test_bit(GD_DEAD, &disk->state))
347 bio_wouldblock_error(bio);
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
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))
373 void blk_queue_exit(struct request_queue *q)
375 percpu_ref_put(&q->q_usage_counter);
378 static void blk_queue_usage_counter_release(struct percpu_ref *ref)
380 struct request_queue *q =
381 container_of(ref, struct request_queue, q_usage_counter);
383 wake_up_all(&q->mq_freeze_wq);
386 static void blk_rq_timed_out_timer(struct timer_list *t)
388 struct request_queue *q = from_timer(q, t, timeout);
390 kblockd_schedule_work(&q->timeout_work);
393 static void blk_timeout_work(struct work_struct *work)
397 struct request_queue *blk_alloc_queue(int node_id)
399 struct request_queue *q;
401 q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO,
406 q->last_merge = NULL;
408 q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL);
412 q->stats = blk_alloc_queue_stats();
418 atomic_set(&q->nr_active_requests_shared_tags, 0);
420 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
421 INIT_WORK(&q->timeout_work, blk_timeout_work);
422 INIT_LIST_HEAD(&q->icq_list);
424 refcount_set(&q->refs, 1);
425 mutex_init(&q->debugfs_mutex);
426 mutex_init(&q->sysfs_lock);
427 mutex_init(&q->sysfs_dir_lock);
428 mutex_init(&q->rq_qos_mutex);
429 spin_lock_init(&q->queue_lock);
431 init_waitqueue_head(&q->mq_freeze_wq);
432 mutex_init(&q->mq_freeze_lock);
435 * Init percpu_ref in atomic mode so that it's faster to shutdown.
436 * See blk_register_queue() for details.
438 if (percpu_ref_init(&q->q_usage_counter,
439 blk_queue_usage_counter_release,
440 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
443 blk_set_default_limits(&q->limits);
444 q->nr_requests = BLKDEV_DEFAULT_RQ;
449 blk_free_queue_stats(q->stats);
451 ida_free(&blk_queue_ida, q->id);
453 kmem_cache_free(blk_requestq_cachep, q);
458 * blk_get_queue - increment the request_queue refcount
459 * @q: the request_queue structure to increment the refcount for
461 * Increment the refcount of the request_queue kobject.
463 * Context: Any context.
465 bool blk_get_queue(struct request_queue *q)
467 if (unlikely(blk_queue_dying(q)))
469 refcount_inc(&q->refs);
472 EXPORT_SYMBOL(blk_get_queue);
474 #ifdef CONFIG_FAIL_MAKE_REQUEST
476 static DECLARE_FAULT_ATTR(fail_make_request);
478 static int __init setup_fail_make_request(char *str)
480 return setup_fault_attr(&fail_make_request, str);
482 __setup("fail_make_request=", setup_fail_make_request);
484 bool should_fail_request(struct block_device *part, unsigned int bytes)
486 return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
489 static int __init fail_make_request_debugfs(void)
491 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
492 NULL, &fail_make_request);
494 return PTR_ERR_OR_ZERO(dir);
497 late_initcall(fail_make_request_debugfs);
498 #endif /* CONFIG_FAIL_MAKE_REQUEST */
500 static inline void bio_check_ro(struct bio *bio)
502 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
503 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
506 if (bio->bi_bdev->bd_ro_warned)
509 bio->bi_bdev->bd_ro_warned = true;
511 * Use ioctl to set underlying disk of raid/dm to read-only
514 pr_warn("Trying to write to read-only block-device %pg\n",
519 static noinline int should_fail_bio(struct bio *bio)
521 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
525 ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
528 * Check whether this bio extends beyond the end of the device or partition.
529 * This may well happen - the kernel calls bread() without checking the size of
530 * the device, e.g., when mounting a file system.
532 static inline int bio_check_eod(struct bio *bio)
534 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
535 unsigned int nr_sectors = bio_sectors(bio);
538 (nr_sectors > maxsector ||
539 bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
540 pr_info_ratelimited("%s: attempt to access beyond end of device\n"
541 "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n",
542 current->comm, bio->bi_bdev, bio->bi_opf,
543 bio->bi_iter.bi_sector, nr_sectors, maxsector);
550 * Remap block n of partition p to block n+start(p) of the disk.
552 static int blk_partition_remap(struct bio *bio)
554 struct block_device *p = bio->bi_bdev;
556 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
558 if (bio_sectors(bio)) {
559 bio->bi_iter.bi_sector += p->bd_start_sect;
560 trace_block_bio_remap(bio, p->bd_dev,
561 bio->bi_iter.bi_sector -
564 bio_set_flag(bio, BIO_REMAPPED);
569 * Check write append to a zoned block device.
571 static inline blk_status_t blk_check_zone_append(struct request_queue *q,
574 int nr_sectors = bio_sectors(bio);
576 /* Only applicable to zoned block devices */
577 if (!bdev_is_zoned(bio->bi_bdev))
578 return BLK_STS_NOTSUPP;
580 /* The bio sector must point to the start of a sequential zone */
581 if (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) ||
582 !bio_zone_is_seq(bio))
583 return BLK_STS_IOERR;
586 * Not allowed to cross zone boundaries. Otherwise, the BIO will be
587 * split and could result in non-contiguous sectors being written in
590 if (nr_sectors > q->limits.chunk_sectors)
591 return BLK_STS_IOERR;
593 /* Make sure the BIO is small enough and will not get split */
594 if (nr_sectors > q->limits.max_zone_append_sectors)
595 return BLK_STS_IOERR;
597 bio->bi_opf |= REQ_NOMERGE;
602 static void __submit_bio(struct bio *bio)
604 if (unlikely(!blk_crypto_bio_prep(&bio)))
607 if (!bio->bi_bdev->bd_has_submit_bio) {
608 blk_mq_submit_bio(bio);
609 } else if (likely(bio_queue_enter(bio) == 0)) {
610 struct gendisk *disk = bio->bi_bdev->bd_disk;
612 disk->fops->submit_bio(bio);
613 blk_queue_exit(disk->queue);
618 * The loop in this function may be a bit non-obvious, and so deserves some
621 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure
622 * that), so we have a list with a single bio.
623 * - We pretend that we have just taken it off a longer list, so we assign
624 * bio_list to a pointer to the bio_list_on_stack, thus initialising the
625 * bio_list of new bios to be added. ->submit_bio() may indeed add some more
626 * bios through a recursive call to submit_bio_noacct. If it did, we find a
627 * non-NULL value in bio_list and re-enter the loop from the top.
628 * - In this case we really did just take the bio of the top of the list (no
629 * pretending) and so remove it from bio_list, and call into ->submit_bio()
632 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
633 * bio_list_on_stack[1] contains bios that were submitted before the current
634 * ->submit_bio, but that haven't been processed yet.
636 static void __submit_bio_noacct(struct bio *bio)
638 struct bio_list bio_list_on_stack[2];
640 BUG_ON(bio->bi_next);
642 bio_list_init(&bio_list_on_stack[0]);
643 current->bio_list = bio_list_on_stack;
646 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
647 struct bio_list lower, same;
650 * Create a fresh bio_list for all subordinate requests.
652 bio_list_on_stack[1] = bio_list_on_stack[0];
653 bio_list_init(&bio_list_on_stack[0]);
658 * Sort new bios into those for a lower level and those for the
661 bio_list_init(&lower);
662 bio_list_init(&same);
663 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
664 if (q == bdev_get_queue(bio->bi_bdev))
665 bio_list_add(&same, bio);
667 bio_list_add(&lower, bio);
670 * Now assemble so we handle the lowest level first.
672 bio_list_merge(&bio_list_on_stack[0], &lower);
673 bio_list_merge(&bio_list_on_stack[0], &same);
674 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
675 } while ((bio = bio_list_pop(&bio_list_on_stack[0])));
677 current->bio_list = NULL;
680 static void __submit_bio_noacct_mq(struct bio *bio)
682 struct bio_list bio_list[2] = { };
684 current->bio_list = bio_list;
688 } while ((bio = bio_list_pop(&bio_list[0])));
690 current->bio_list = NULL;
693 void submit_bio_noacct_nocheck(struct bio *bio)
695 blk_cgroup_bio_start(bio);
696 blkcg_bio_issue_init(bio);
698 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
699 trace_block_bio_queue(bio);
701 * Now that enqueuing has been traced, we need to trace
702 * completion as well.
704 bio_set_flag(bio, BIO_TRACE_COMPLETION);
708 * We only want one ->submit_bio to be active at a time, else stack
709 * usage with stacked devices could be a problem. Use current->bio_list
710 * to collect a list of requests submited by a ->submit_bio method while
711 * it is active, and then process them after it returned.
713 if (current->bio_list)
714 bio_list_add(¤t->bio_list[0], bio);
715 else if (!bio->bi_bdev->bd_has_submit_bio)
716 __submit_bio_noacct_mq(bio);
718 __submit_bio_noacct(bio);
722 * submit_bio_noacct - re-submit a bio to the block device layer for I/O
723 * @bio: The bio describing the location in memory and on the device.
725 * This is a version of submit_bio() that shall only be used for I/O that is
726 * resubmitted to lower level drivers by stacking block drivers. All file
727 * systems and other upper level users of the block layer should use
728 * submit_bio() instead.
730 void submit_bio_noacct(struct bio *bio)
732 struct block_device *bdev = bio->bi_bdev;
733 struct request_queue *q = bdev_get_queue(bdev);
734 blk_status_t status = BLK_STS_IOERR;
739 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
740 * if queue does not support NOWAIT.
742 if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev))
745 if (should_fail_bio(bio))
748 if (!bio_flagged(bio, BIO_REMAPPED)) {
749 if (unlikely(bio_check_eod(bio)))
751 if (bdev->bd_partno && unlikely(blk_partition_remap(bio)))
756 * Filter flush bio's early so that bio based drivers without flush
757 * support don't have to worry about them.
759 if (op_is_flush(bio->bi_opf)) {
760 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE &&
761 bio_op(bio) != REQ_OP_ZONE_APPEND))
763 if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
764 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
765 if (!bio_sectors(bio)) {
772 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
773 bio_clear_polled(bio);
775 switch (bio_op(bio)) {
781 * REQ_OP_FLUSH can't be submitted through bios, it is only
782 * synthetized in struct request by the flush state machine.
786 if (!bdev_max_discard_sectors(bdev))
789 case REQ_OP_SECURE_ERASE:
790 if (!bdev_max_secure_erase_sectors(bdev))
793 case REQ_OP_ZONE_APPEND:
794 status = blk_check_zone_append(q, bio);
795 if (status != BLK_STS_OK)
798 case REQ_OP_WRITE_ZEROES:
799 if (!q->limits.max_write_zeroes_sectors)
802 case REQ_OP_ZONE_RESET:
803 case REQ_OP_ZONE_OPEN:
804 case REQ_OP_ZONE_CLOSE:
805 case REQ_OP_ZONE_FINISH:
806 if (!bdev_is_zoned(bio->bi_bdev))
809 case REQ_OP_ZONE_RESET_ALL:
810 if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q))
816 * Driver private operations are only used with passthrough
824 if (blk_throtl_bio(bio))
826 submit_bio_noacct_nocheck(bio);
830 status = BLK_STS_NOTSUPP;
832 bio->bi_status = status;
835 EXPORT_SYMBOL(submit_bio_noacct);
837 static void bio_set_ioprio(struct bio *bio)
839 /* Nobody set ioprio so far? Initialize it based on task's nice value */
840 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
841 bio->bi_ioprio = get_current_ioprio();
842 blkcg_set_ioprio(bio);
846 * submit_bio - submit a bio to the block device layer for I/O
847 * @bio: The &struct bio which describes the I/O
849 * submit_bio() is used to submit I/O requests to block devices. It is passed a
850 * fully set up &struct bio that describes the I/O that needs to be done. The
851 * bio will be send to the device described by the bi_bdev field.
853 * The success/failure status of the request, along with notification of
854 * completion, is delivered asynchronously through the ->bi_end_io() callback
855 * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has
858 void submit_bio(struct bio *bio)
860 if (bio_op(bio) == REQ_OP_READ) {
861 task_io_account_read(bio->bi_iter.bi_size);
862 count_vm_events(PGPGIN, bio_sectors(bio));
863 } else if (bio_op(bio) == REQ_OP_WRITE) {
864 count_vm_events(PGPGOUT, bio_sectors(bio));
868 submit_bio_noacct(bio);
870 EXPORT_SYMBOL(submit_bio);
873 * bio_poll - poll for BIO completions
874 * @bio: bio to poll for
875 * @iob: batches of IO
876 * @flags: BLK_POLL_* flags that control the behavior
878 * Poll for completions on queue associated with the bio. Returns number of
879 * completed entries found.
881 * Note: the caller must either be the context that submitted @bio, or
882 * be in a RCU critical section to prevent freeing of @bio.
884 int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
886 blk_qc_t cookie = READ_ONCE(bio->bi_cookie);
887 struct block_device *bdev;
888 struct request_queue *q;
891 bdev = READ_ONCE(bio->bi_bdev);
895 q = bdev_get_queue(bdev);
896 if (cookie == BLK_QC_T_NONE ||
897 !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
901 * As the requests that require a zone lock are not plugged in the
902 * first place, directly accessing the plug instead of using
903 * blk_mq_plug() should not have any consequences during flushing for
906 blk_flush_plug(current->plug, false);
909 * We need to be able to enter a frozen queue, similar to how
910 * timeouts also need to do that. If that is blocked, then we can
911 * have pending IO when a queue freeze is started, and then the
912 * wait for the freeze to finish will wait for polled requests to
913 * timeout as the poller is preventer from entering the queue and
914 * completing them. As long as we prevent new IO from being queued,
915 * that should be all that matters.
917 if (!percpu_ref_tryget(&q->q_usage_counter))
919 if (queue_is_mq(q)) {
920 ret = blk_mq_poll(q, cookie, iob, flags);
922 struct gendisk *disk = q->disk;
924 if (disk && disk->fops->poll_bio)
925 ret = disk->fops->poll_bio(bio, iob, flags);
930 EXPORT_SYMBOL_GPL(bio_poll);
933 * Helper to implement file_operations.iopoll. Requires the bio to be stored
934 * in iocb->private, and cleared before freeing the bio.
936 int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,
943 * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can
944 * point to a freshly allocated bio at this point. If that happens
945 * we have a few cases to consider:
947 * 1) the bio is beeing initialized and bi_bdev is NULL. We can just
948 * simply nothing in this case
949 * 2) the bio points to a not poll enabled device. bio_poll will catch
951 * 3) the bio points to a poll capable device, including but not
952 * limited to the one that the original bio pointed to. In this
953 * case we will call into the actual poll method and poll for I/O,
954 * even if we don't need to, but it won't cause harm either.
956 * For cases 2) and 3) above the RCU grace period ensures that bi_bdev
957 * is still allocated. Because partitions hold a reference to the whole
958 * device bdev and thus disk, the disk is also still valid. Grabbing
959 * a reference to the queue in bio_poll() ensures the hctxs and requests
960 * are still valid as well.
963 bio = READ_ONCE(kiocb->private);
965 ret = bio_poll(bio, iob, flags);
970 EXPORT_SYMBOL_GPL(iocb_bio_iopoll);
972 void update_io_ticks(struct block_device *part, unsigned long now, bool end)
976 stamp = READ_ONCE(part->bd_stamp);
977 if (unlikely(time_after(now, stamp))) {
978 if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now)))
979 __part_stat_add(part, io_ticks, end ? now - stamp : 1);
981 if (part->bd_partno) {
982 part = bdev_whole(part);
987 unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,
988 unsigned long start_time)
991 update_io_ticks(bdev, start_time, false);
992 part_stat_local_inc(bdev, in_flight[op_is_write(op)]);
997 EXPORT_SYMBOL(bdev_start_io_acct);
1000 * bio_start_io_acct - start I/O accounting for bio based drivers
1001 * @bio: bio to start account for
1003 * Returns the start time that should be passed back to bio_end_io_acct().
1005 unsigned long bio_start_io_acct(struct bio *bio)
1007 return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies);
1009 EXPORT_SYMBOL_GPL(bio_start_io_acct);
1011 void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
1012 unsigned int sectors, unsigned long start_time)
1014 const int sgrp = op_stat_group(op);
1015 unsigned long now = READ_ONCE(jiffies);
1016 unsigned long duration = now - start_time;
1019 update_io_ticks(bdev, now, true);
1020 part_stat_inc(bdev, ios[sgrp]);
1021 part_stat_add(bdev, sectors[sgrp], sectors);
1022 part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));
1023 part_stat_local_dec(bdev, in_flight[op_is_write(op)]);
1026 EXPORT_SYMBOL(bdev_end_io_acct);
1028 void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
1029 struct block_device *orig_bdev)
1031 bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time);
1033 EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
1036 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
1037 * @q : the queue of the device being checked
1040 * Check if underlying low-level drivers of a device are busy.
1041 * If the drivers want to export their busy state, they must set own
1042 * exporting function using blk_queue_lld_busy() first.
1044 * Basically, this function is used only by request stacking drivers
1045 * to stop dispatching requests to underlying devices when underlying
1046 * devices are busy. This behavior helps more I/O merging on the queue
1047 * of the request stacking driver and prevents I/O throughput regression
1048 * on burst I/O load.
1051 * 0 - Not busy (The request stacking driver should dispatch request)
1052 * 1 - Busy (The request stacking driver should stop dispatching request)
1054 int blk_lld_busy(struct request_queue *q)
1056 if (queue_is_mq(q) && q->mq_ops->busy)
1057 return q->mq_ops->busy(q);
1061 EXPORT_SYMBOL_GPL(blk_lld_busy);
1063 int kblockd_schedule_work(struct work_struct *work)
1065 return queue_work(kblockd_workqueue, work);
1067 EXPORT_SYMBOL(kblockd_schedule_work);
1069 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
1070 unsigned long delay)
1072 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
1074 EXPORT_SYMBOL(kblockd_mod_delayed_work_on);
1076 void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios)
1078 struct task_struct *tsk = current;
1081 * If this is a nested plug, don't actually assign it.
1086 plug->mq_list = NULL;
1087 plug->cached_rq = NULL;
1088 plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT);
1090 plug->multiple_queues = false;
1091 plug->has_elevator = false;
1092 INIT_LIST_HEAD(&plug->cb_list);
1095 * Store ordering should not be needed here, since a potential
1096 * preempt will imply a full memory barrier
1102 * blk_start_plug - initialize blk_plug and track it inside the task_struct
1103 * @plug: The &struct blk_plug that needs to be initialized
1106 * blk_start_plug() indicates to the block layer an intent by the caller
1107 * to submit multiple I/O requests in a batch. The block layer may use
1108 * this hint to defer submitting I/Os from the caller until blk_finish_plug()
1109 * is called. However, the block layer may choose to submit requests
1110 * before a call to blk_finish_plug() if the number of queued I/Os
1111 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
1112 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
1113 * the task schedules (see below).
1115 * Tracking blk_plug inside the task_struct will help with auto-flushing the
1116 * pending I/O should the task end up blocking between blk_start_plug() and
1117 * blk_finish_plug(). This is important from a performance perspective, but
1118 * also ensures that we don't deadlock. For instance, if the task is blocking
1119 * for a memory allocation, memory reclaim could end up wanting to free a
1120 * page belonging to that request that is currently residing in our private
1121 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
1122 * this kind of deadlock.
1124 void blk_start_plug(struct blk_plug *plug)
1126 blk_start_plug_nr_ios(plug, 1);
1128 EXPORT_SYMBOL(blk_start_plug);
1130 static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
1132 LIST_HEAD(callbacks);
1134 while (!list_empty(&plug->cb_list)) {
1135 list_splice_init(&plug->cb_list, &callbacks);
1137 while (!list_empty(&callbacks)) {
1138 struct blk_plug_cb *cb = list_first_entry(&callbacks,
1141 list_del(&cb->list);
1142 cb->callback(cb, from_schedule);
1147 struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
1150 struct blk_plug *plug = current->plug;
1151 struct blk_plug_cb *cb;
1156 list_for_each_entry(cb, &plug->cb_list, list)
1157 if (cb->callback == unplug && cb->data == data)
1160 /* Not currently on the callback list */
1161 BUG_ON(size < sizeof(*cb));
1162 cb = kzalloc(size, GFP_ATOMIC);
1165 cb->callback = unplug;
1166 list_add(&cb->list, &plug->cb_list);
1170 EXPORT_SYMBOL(blk_check_plugged);
1172 void __blk_flush_plug(struct blk_plug *plug, bool from_schedule)
1174 if (!list_empty(&plug->cb_list))
1175 flush_plug_callbacks(plug, from_schedule);
1176 blk_mq_flush_plug_list(plug, from_schedule);
1178 * Unconditionally flush out cached requests, even if the unplug
1179 * event came from schedule. Since we know hold references to the
1180 * queue for cached requests, we don't want a blocked task holding
1181 * up a queue freeze/quiesce event.
1183 if (unlikely(!rq_list_empty(plug->cached_rq)))
1184 blk_mq_free_plug_rqs(plug);
1188 * blk_finish_plug - mark the end of a batch of submitted I/O
1189 * @plug: The &struct blk_plug passed to blk_start_plug()
1192 * Indicate that a batch of I/O submissions is complete. This function
1193 * must be paired with an initial call to blk_start_plug(). The intent
1194 * is to allow the block layer to optimize I/O submission. See the
1195 * documentation for blk_start_plug() for more information.
1197 void blk_finish_plug(struct blk_plug *plug)
1199 if (plug == current->plug) {
1200 __blk_flush_plug(plug, false);
1201 current->plug = NULL;
1204 EXPORT_SYMBOL(blk_finish_plug);
1206 void blk_io_schedule(void)
1208 /* Prevent hang_check timer from firing at us during very long I/O */
1209 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;
1212 io_schedule_timeout(timeout);
1216 EXPORT_SYMBOL_GPL(blk_io_schedule);
1218 int __init blk_dev_init(void)
1220 BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS));
1221 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1222 sizeof_field(struct request, cmd_flags));
1223 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1224 sizeof_field(struct bio, bi_opf));
1226 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
1227 kblockd_workqueue = alloc_workqueue("kblockd",
1228 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1229 if (!kblockd_workqueue)
1230 panic("Failed to create kblockd\n");
1232 blk_requestq_cachep = kmem_cache_create("request_queue",
1233 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
1235 blk_debugfs_root = debugfs_create_dir("block", NULL);