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-mq.h>
20 #include <linux/blk-pm.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/blk-cgroup.h>
38 #include <linux/t10-pi.h>
39 #include <linux/debugfs.h>
40 #include <linux/bpf.h>
41 #include <linux/psi.h>
42 #include <linux/sched/sysctl.h>
43 #include <linux/blk-crypto.h>
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/block.h>
50 #include "blk-mq-sched.h"
53 struct dentry
*blk_debugfs_root
;
55 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap
);
56 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap
);
57 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete
);
58 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split
);
59 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug
);
60 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert
);
62 DEFINE_IDA(blk_queue_ida
);
65 * For queue allocation
67 struct kmem_cache
*blk_requestq_cachep
;
70 * Controlling structure to kblockd
72 static struct workqueue_struct
*kblockd_workqueue
;
75 * blk_queue_flag_set - atomically set a queue flag
76 * @flag: flag to be set
79 void blk_queue_flag_set(unsigned int flag
, struct request_queue
*q
)
81 set_bit(flag
, &q
->queue_flags
);
83 EXPORT_SYMBOL(blk_queue_flag_set
);
86 * blk_queue_flag_clear - atomically clear a queue flag
87 * @flag: flag to be cleared
90 void blk_queue_flag_clear(unsigned int flag
, struct request_queue
*q
)
92 clear_bit(flag
, &q
->queue_flags
);
94 EXPORT_SYMBOL(blk_queue_flag_clear
);
97 * blk_queue_flag_test_and_set - atomically test and set a queue flag
98 * @flag: flag to be set
101 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
102 * the flag was already set.
104 bool blk_queue_flag_test_and_set(unsigned int flag
, struct request_queue
*q
)
106 return test_and_set_bit(flag
, &q
->queue_flags
);
108 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set
);
110 void blk_rq_init(struct request_queue
*q
, struct request
*rq
)
112 memset(rq
, 0, sizeof(*rq
));
114 INIT_LIST_HEAD(&rq
->queuelist
);
116 rq
->__sector
= (sector_t
) -1;
117 INIT_HLIST_NODE(&rq
->hash
);
118 RB_CLEAR_NODE(&rq
->rb_node
);
119 rq
->tag
= BLK_MQ_NO_TAG
;
120 rq
->internal_tag
= BLK_MQ_NO_TAG
;
121 rq
->start_time_ns
= ktime_get_ns();
123 blk_crypto_rq_set_defaults(rq
);
125 EXPORT_SYMBOL(blk_rq_init
);
127 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
128 static const char *const blk_op_name
[] = {
132 REQ_OP_NAME(DISCARD
),
133 REQ_OP_NAME(SECURE_ERASE
),
134 REQ_OP_NAME(ZONE_RESET
),
135 REQ_OP_NAME(ZONE_RESET_ALL
),
136 REQ_OP_NAME(ZONE_OPEN
),
137 REQ_OP_NAME(ZONE_CLOSE
),
138 REQ_OP_NAME(ZONE_FINISH
),
139 REQ_OP_NAME(ZONE_APPEND
),
140 REQ_OP_NAME(WRITE_SAME
),
141 REQ_OP_NAME(WRITE_ZEROES
),
143 REQ_OP_NAME(DRV_OUT
),
148 * blk_op_str - Return string XXX in the REQ_OP_XXX.
151 * Description: Centralize block layer function to convert REQ_OP_XXX into
152 * string format. Useful in the debugging and tracing bio or request. For
153 * invalid REQ_OP_XXX it returns string "UNKNOWN".
155 inline const char *blk_op_str(unsigned int op
)
157 const char *op_str
= "UNKNOWN";
159 if (op
< ARRAY_SIZE(blk_op_name
) && blk_op_name
[op
])
160 op_str
= blk_op_name
[op
];
164 EXPORT_SYMBOL_GPL(blk_op_str
);
166 static const struct {
170 [BLK_STS_OK
] = { 0, "" },
171 [BLK_STS_NOTSUPP
] = { -EOPNOTSUPP
, "operation not supported" },
172 [BLK_STS_TIMEOUT
] = { -ETIMEDOUT
, "timeout" },
173 [BLK_STS_NOSPC
] = { -ENOSPC
, "critical space allocation" },
174 [BLK_STS_TRANSPORT
] = { -ENOLINK
, "recoverable transport" },
175 [BLK_STS_TARGET
] = { -EREMOTEIO
, "critical target" },
176 [BLK_STS_NEXUS
] = { -EBADE
, "critical nexus" },
177 [BLK_STS_MEDIUM
] = { -ENODATA
, "critical medium" },
178 [BLK_STS_PROTECTION
] = { -EILSEQ
, "protection" },
179 [BLK_STS_RESOURCE
] = { -ENOMEM
, "kernel resource" },
180 [BLK_STS_DEV_RESOURCE
] = { -EBUSY
, "device resource" },
181 [BLK_STS_AGAIN
] = { -EAGAIN
, "nonblocking retry" },
183 /* device mapper special case, should not leak out: */
184 [BLK_STS_DM_REQUEUE
] = { -EREMCHG
, "dm internal retry" },
186 /* zone device specific errors */
187 [BLK_STS_ZONE_OPEN_RESOURCE
] = { -ETOOMANYREFS
, "open zones exceeded" },
188 [BLK_STS_ZONE_ACTIVE_RESOURCE
] = { -EOVERFLOW
, "active zones exceeded" },
190 /* everything else not covered above: */
191 [BLK_STS_IOERR
] = { -EIO
, "I/O" },
194 blk_status_t
errno_to_blk_status(int errno
)
198 for (i
= 0; i
< ARRAY_SIZE(blk_errors
); i
++) {
199 if (blk_errors
[i
].errno
== errno
)
200 return (__force blk_status_t
)i
;
203 return BLK_STS_IOERR
;
205 EXPORT_SYMBOL_GPL(errno_to_blk_status
);
207 int blk_status_to_errno(blk_status_t status
)
209 int idx
= (__force
int)status
;
211 if (WARN_ON_ONCE(idx
>= ARRAY_SIZE(blk_errors
)))
213 return blk_errors
[idx
].errno
;
215 EXPORT_SYMBOL_GPL(blk_status_to_errno
);
217 static void print_req_error(struct request
*req
, blk_status_t status
,
220 int idx
= (__force
int)status
;
222 if (WARN_ON_ONCE(idx
>= ARRAY_SIZE(blk_errors
)))
225 printk_ratelimited(KERN_ERR
226 "%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
227 "phys_seg %u prio class %u\n",
228 caller
, blk_errors
[idx
].name
,
229 req
->rq_disk
? req
->rq_disk
->disk_name
: "?",
230 blk_rq_pos(req
), req_op(req
), blk_op_str(req_op(req
)),
231 req
->cmd_flags
& ~REQ_OP_MASK
,
232 req
->nr_phys_segments
,
233 IOPRIO_PRIO_CLASS(req
->ioprio
));
236 static void req_bio_endio(struct request
*rq
, struct bio
*bio
,
237 unsigned int nbytes
, blk_status_t error
)
240 bio
->bi_status
= error
;
242 if (unlikely(rq
->rq_flags
& RQF_QUIET
))
243 bio_set_flag(bio
, BIO_QUIET
);
245 bio_advance(bio
, nbytes
);
247 if (req_op(rq
) == REQ_OP_ZONE_APPEND
&& error
== BLK_STS_OK
) {
249 * Partial zone append completions cannot be supported as the
250 * BIO fragments may end up not being written sequentially.
252 if (bio
->bi_iter
.bi_size
)
253 bio
->bi_status
= BLK_STS_IOERR
;
255 bio
->bi_iter
.bi_sector
= rq
->__sector
;
258 /* don't actually finish bio if it's part of flush sequence */
259 if (bio
->bi_iter
.bi_size
== 0 && !(rq
->rq_flags
& RQF_FLUSH_SEQ
))
263 void blk_dump_rq_flags(struct request
*rq
, char *msg
)
265 printk(KERN_INFO
"%s: dev %s: flags=%llx\n", msg
,
266 rq
->rq_disk
? rq
->rq_disk
->disk_name
: "?",
267 (unsigned long long) rq
->cmd_flags
);
269 printk(KERN_INFO
" sector %llu, nr/cnr %u/%u\n",
270 (unsigned long long)blk_rq_pos(rq
),
271 blk_rq_sectors(rq
), blk_rq_cur_sectors(rq
));
272 printk(KERN_INFO
" bio %p, biotail %p, len %u\n",
273 rq
->bio
, rq
->biotail
, blk_rq_bytes(rq
));
275 EXPORT_SYMBOL(blk_dump_rq_flags
);
278 * blk_sync_queue - cancel any pending callbacks on a queue
282 * The block layer may perform asynchronous callback activity
283 * on a queue, such as calling the unplug function after a timeout.
284 * A block device may call blk_sync_queue to ensure that any
285 * such activity is cancelled, thus allowing it to release resources
286 * that the callbacks might use. The caller must already have made sure
287 * that its ->submit_bio will not re-add plugging prior to calling
290 * This function does not cancel any asynchronous activity arising
291 * out of elevator or throttling code. That would require elevator_exit()
292 * and blkcg_exit_queue() to be called with queue lock initialized.
295 void blk_sync_queue(struct request_queue
*q
)
297 del_timer_sync(&q
->timeout
);
298 cancel_work_sync(&q
->timeout_work
);
300 EXPORT_SYMBOL(blk_sync_queue
);
303 * blk_set_pm_only - increment pm_only counter
304 * @q: request queue pointer
306 void blk_set_pm_only(struct request_queue
*q
)
308 atomic_inc(&q
->pm_only
);
310 EXPORT_SYMBOL_GPL(blk_set_pm_only
);
312 void blk_clear_pm_only(struct request_queue
*q
)
316 pm_only
= atomic_dec_return(&q
->pm_only
);
317 WARN_ON_ONCE(pm_only
< 0);
319 wake_up_all(&q
->mq_freeze_wq
);
321 EXPORT_SYMBOL_GPL(blk_clear_pm_only
);
324 * blk_put_queue - decrement the request_queue refcount
325 * @q: the request_queue structure to decrement the refcount for
327 * Decrements the refcount of the request_queue kobject. When this reaches 0
328 * we'll have blk_release_queue() called.
330 * Context: Any context, but the last reference must not be dropped from
333 void blk_put_queue(struct request_queue
*q
)
335 kobject_put(&q
->kobj
);
337 EXPORT_SYMBOL(blk_put_queue
);
339 void blk_queue_start_drain(struct request_queue
*q
)
342 * When queue DYING flag is set, we need to block new req
343 * entering queue, so we call blk_freeze_queue_start() to
344 * prevent I/O from crossing blk_queue_enter().
346 blk_freeze_queue_start(q
);
348 blk_mq_wake_waiters(q
);
349 /* Make blk_queue_enter() reexamine the DYING flag. */
350 wake_up_all(&q
->mq_freeze_wq
);
353 void blk_set_queue_dying(struct request_queue
*q
)
355 blk_queue_flag_set(QUEUE_FLAG_DYING
, q
);
356 blk_queue_start_drain(q
);
358 EXPORT_SYMBOL_GPL(blk_set_queue_dying
);
361 * blk_cleanup_queue - shutdown a request queue
362 * @q: request queue to shutdown
364 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
365 * put it. All future requests will be failed immediately with -ENODEV.
369 void blk_cleanup_queue(struct request_queue
*q
)
371 /* cannot be called from atomic context */
374 WARN_ON_ONCE(blk_queue_registered(q
));
376 /* mark @q DYING, no new request or merges will be allowed afterwards */
377 blk_set_queue_dying(q
);
379 blk_queue_flag_set(QUEUE_FLAG_NOMERGES
, q
);
380 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES
, q
);
383 * Drain all requests queued before DYING marking. Set DEAD flag to
384 * prevent that blk_mq_run_hw_queues() accesses the hardware queues
385 * after draining finished.
389 blk_queue_flag_set(QUEUE_FLAG_DEAD
, q
);
393 blk_mq_exit_queue(q
);
396 * In theory, request pool of sched_tags belongs to request queue.
397 * However, the current implementation requires tag_set for freeing
398 * requests, so free the pool now.
400 * Queue has become frozen, there can't be any in-queue requests, so
401 * it is safe to free requests now.
403 mutex_lock(&q
->sysfs_lock
);
405 blk_mq_sched_free_requests(q
);
406 mutex_unlock(&q
->sysfs_lock
);
408 percpu_ref_exit(&q
->q_usage_counter
);
410 /* @q is and will stay empty, shutdown and put */
413 EXPORT_SYMBOL(blk_cleanup_queue
);
415 static bool blk_try_enter_queue(struct request_queue
*q
, bool pm
)
418 if (!percpu_ref_tryget_live(&q
->q_usage_counter
))
422 * The code that increments the pm_only counter must ensure that the
423 * counter is globally visible before the queue is unfrozen.
425 if (blk_queue_pm_only(q
) &&
426 (!pm
|| queue_rpm_status(q
) == RPM_SUSPENDED
))
433 percpu_ref_put(&q
->q_usage_counter
);
440 * blk_queue_enter() - try to increase q->q_usage_counter
441 * @q: request queue pointer
442 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
444 int blk_queue_enter(struct request_queue
*q
, blk_mq_req_flags_t flags
)
446 const bool pm
= flags
& BLK_MQ_REQ_PM
;
448 while (!blk_try_enter_queue(q
, pm
)) {
449 if (flags
& BLK_MQ_REQ_NOWAIT
)
453 * read pair of barrier in blk_freeze_queue_start(), we need to
454 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
455 * reading .mq_freeze_depth or queue dying flag, otherwise the
456 * following wait may never return if the two reads are
460 wait_event(q
->mq_freeze_wq
,
461 (!q
->mq_freeze_depth
&&
462 blk_pm_resume_queue(pm
, q
)) ||
464 if (blk_queue_dying(q
))
471 static inline int bio_queue_enter(struct bio
*bio
)
473 struct gendisk
*disk
= bio
->bi_bdev
->bd_disk
;
474 struct request_queue
*q
= disk
->queue
;
476 while (!blk_try_enter_queue(q
, false)) {
477 if (bio
->bi_opf
& REQ_NOWAIT
) {
478 if (test_bit(GD_DEAD
, &disk
->state
))
480 bio_wouldblock_error(bio
);
485 * read pair of barrier in blk_freeze_queue_start(), we need to
486 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
487 * reading .mq_freeze_depth or queue dying flag, otherwise the
488 * following wait may never return if the two reads are
492 wait_event(q
->mq_freeze_wq
,
493 (!q
->mq_freeze_depth
&&
494 blk_pm_resume_queue(false, q
)) ||
495 test_bit(GD_DEAD
, &disk
->state
));
496 if (test_bit(GD_DEAD
, &disk
->state
))
506 void blk_queue_exit(struct request_queue
*q
)
508 percpu_ref_put(&q
->q_usage_counter
);
511 static void blk_queue_usage_counter_release(struct percpu_ref
*ref
)
513 struct request_queue
*q
=
514 container_of(ref
, struct request_queue
, q_usage_counter
);
516 wake_up_all(&q
->mq_freeze_wq
);
519 static void blk_rq_timed_out_timer(struct timer_list
*t
)
521 struct request_queue
*q
= from_timer(q
, t
, timeout
);
523 kblockd_schedule_work(&q
->timeout_work
);
526 static void blk_timeout_work(struct work_struct
*work
)
530 struct request_queue
*blk_alloc_queue(int node_id
)
532 struct request_queue
*q
;
535 q
= kmem_cache_alloc_node(blk_requestq_cachep
,
536 GFP_KERNEL
| __GFP_ZERO
, node_id
);
540 q
->last_merge
= NULL
;
542 q
->id
= ida_simple_get(&blk_queue_ida
, 0, 0, GFP_KERNEL
);
546 ret
= bioset_init(&q
->bio_split
, BIO_POOL_SIZE
, 0, 0);
550 q
->stats
= blk_alloc_queue_stats();
556 atomic_set(&q
->nr_active_requests_shared_sbitmap
, 0);
558 timer_setup(&q
->timeout
, blk_rq_timed_out_timer
, 0);
559 INIT_WORK(&q
->timeout_work
, blk_timeout_work
);
560 INIT_LIST_HEAD(&q
->icq_list
);
561 #ifdef CONFIG_BLK_CGROUP
562 INIT_LIST_HEAD(&q
->blkg_list
);
565 kobject_init(&q
->kobj
, &blk_queue_ktype
);
567 mutex_init(&q
->debugfs_mutex
);
568 mutex_init(&q
->sysfs_lock
);
569 mutex_init(&q
->sysfs_dir_lock
);
570 spin_lock_init(&q
->queue_lock
);
572 init_waitqueue_head(&q
->mq_freeze_wq
);
573 mutex_init(&q
->mq_freeze_lock
);
576 * Init percpu_ref in atomic mode so that it's faster to shutdown.
577 * See blk_register_queue() for details.
579 if (percpu_ref_init(&q
->q_usage_counter
,
580 blk_queue_usage_counter_release
,
581 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
584 if (blkcg_init_queue(q
))
587 blk_queue_dma_alignment(q
, 511);
588 blk_set_default_limits(&q
->limits
);
589 q
->nr_requests
= BLKDEV_MAX_RQ
;
594 percpu_ref_exit(&q
->q_usage_counter
);
596 blk_free_queue_stats(q
->stats
);
598 bioset_exit(&q
->bio_split
);
600 ida_simple_remove(&blk_queue_ida
, q
->id
);
602 kmem_cache_free(blk_requestq_cachep
, q
);
607 * blk_get_queue - increment the request_queue refcount
608 * @q: the request_queue structure to increment the refcount for
610 * Increment the refcount of the request_queue kobject.
612 * Context: Any context.
614 bool blk_get_queue(struct request_queue
*q
)
616 if (likely(!blk_queue_dying(q
))) {
623 EXPORT_SYMBOL(blk_get_queue
);
626 * blk_get_request - allocate a request
627 * @q: request queue to allocate a request for
628 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
629 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
631 struct request
*blk_get_request(struct request_queue
*q
, unsigned int op
,
632 blk_mq_req_flags_t flags
)
636 WARN_ON_ONCE(op
& REQ_NOWAIT
);
637 WARN_ON_ONCE(flags
& ~(BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_PM
));
639 req
= blk_mq_alloc_request(q
, op
, flags
);
640 if (!IS_ERR(req
) && q
->mq_ops
->initialize_rq_fn
)
641 q
->mq_ops
->initialize_rq_fn(req
);
645 EXPORT_SYMBOL(blk_get_request
);
647 void blk_put_request(struct request
*req
)
649 blk_mq_free_request(req
);
651 EXPORT_SYMBOL(blk_put_request
);
653 static void handle_bad_sector(struct bio
*bio
, sector_t maxsector
)
655 char b
[BDEVNAME_SIZE
];
657 pr_info_ratelimited("attempt to access beyond end of device\n"
658 "%s: rw=%d, want=%llu, limit=%llu\n",
659 bio_devname(bio
, b
), bio
->bi_opf
,
660 bio_end_sector(bio
), maxsector
);
663 #ifdef CONFIG_FAIL_MAKE_REQUEST
665 static DECLARE_FAULT_ATTR(fail_make_request
);
667 static int __init
setup_fail_make_request(char *str
)
669 return setup_fault_attr(&fail_make_request
, str
);
671 __setup("fail_make_request=", setup_fail_make_request
);
673 static bool should_fail_request(struct block_device
*part
, unsigned int bytes
)
675 return part
->bd_make_it_fail
&& should_fail(&fail_make_request
, bytes
);
678 static int __init
fail_make_request_debugfs(void)
680 struct dentry
*dir
= fault_create_debugfs_attr("fail_make_request",
681 NULL
, &fail_make_request
);
683 return PTR_ERR_OR_ZERO(dir
);
686 late_initcall(fail_make_request_debugfs
);
688 #else /* CONFIG_FAIL_MAKE_REQUEST */
690 static inline bool should_fail_request(struct block_device
*part
,
696 #endif /* CONFIG_FAIL_MAKE_REQUEST */
698 static inline bool bio_check_ro(struct bio
*bio
)
700 if (op_is_write(bio_op(bio
)) && bdev_read_only(bio
->bi_bdev
)) {
701 char b
[BDEVNAME_SIZE
];
703 if (op_is_flush(bio
->bi_opf
) && !bio_sectors(bio
))
707 "Trying to write to read-only block-device %s (partno %d)\n",
708 bio_devname(bio
, b
), bio
->bi_bdev
->bd_partno
);
709 /* Older lvm-tools actually trigger this */
716 static noinline
int should_fail_bio(struct bio
*bio
)
718 if (should_fail_request(bdev_whole(bio
->bi_bdev
), bio
->bi_iter
.bi_size
))
722 ALLOW_ERROR_INJECTION(should_fail_bio
, ERRNO
);
725 * Check whether this bio extends beyond the end of the device or partition.
726 * This may well happen - the kernel calls bread() without checking the size of
727 * the device, e.g., when mounting a file system.
729 static inline int bio_check_eod(struct bio
*bio
)
731 sector_t maxsector
= bdev_nr_sectors(bio
->bi_bdev
);
732 unsigned int nr_sectors
= bio_sectors(bio
);
734 if (nr_sectors
&& maxsector
&&
735 (nr_sectors
> maxsector
||
736 bio
->bi_iter
.bi_sector
> maxsector
- nr_sectors
)) {
737 handle_bad_sector(bio
, maxsector
);
744 * Remap block n of partition p to block n+start(p) of the disk.
746 static int blk_partition_remap(struct bio
*bio
)
748 struct block_device
*p
= bio
->bi_bdev
;
750 if (unlikely(should_fail_request(p
, bio
->bi_iter
.bi_size
)))
752 if (bio_sectors(bio
)) {
753 bio
->bi_iter
.bi_sector
+= p
->bd_start_sect
;
754 trace_block_bio_remap(bio
, p
->bd_dev
,
755 bio
->bi_iter
.bi_sector
-
758 bio_set_flag(bio
, BIO_REMAPPED
);
763 * Check write append to a zoned block device.
765 static inline blk_status_t
blk_check_zone_append(struct request_queue
*q
,
768 sector_t pos
= bio
->bi_iter
.bi_sector
;
769 int nr_sectors
= bio_sectors(bio
);
771 /* Only applicable to zoned block devices */
772 if (!blk_queue_is_zoned(q
))
773 return BLK_STS_NOTSUPP
;
775 /* The bio sector must point to the start of a sequential zone */
776 if (pos
& (blk_queue_zone_sectors(q
) - 1) ||
777 !blk_queue_zone_is_seq(q
, pos
))
778 return BLK_STS_IOERR
;
781 * Not allowed to cross zone boundaries. Otherwise, the BIO will be
782 * split and could result in non-contiguous sectors being written in
785 if (nr_sectors
> q
->limits
.chunk_sectors
)
786 return BLK_STS_IOERR
;
788 /* Make sure the BIO is small enough and will not get split */
789 if (nr_sectors
> q
->limits
.max_zone_append_sectors
)
790 return BLK_STS_IOERR
;
792 bio
->bi_opf
|= REQ_NOMERGE
;
797 static noinline_for_stack
bool submit_bio_checks(struct bio
*bio
)
799 struct block_device
*bdev
= bio
->bi_bdev
;
800 struct request_queue
*q
= bdev
->bd_disk
->queue
;
801 blk_status_t status
= BLK_STS_IOERR
;
802 struct blk_plug
*plug
;
806 plug
= blk_mq_plug(q
, bio
);
807 if (plug
&& plug
->nowait
)
808 bio
->bi_opf
|= REQ_NOWAIT
;
811 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
812 * if queue does not support NOWAIT.
814 if ((bio
->bi_opf
& REQ_NOWAIT
) && !blk_queue_nowait(q
))
817 if (should_fail_bio(bio
))
819 if (unlikely(bio_check_ro(bio
)))
821 if (!bio_flagged(bio
, BIO_REMAPPED
)) {
822 if (unlikely(bio_check_eod(bio
)))
824 if (bdev
->bd_partno
&& unlikely(blk_partition_remap(bio
)))
829 * Filter flush bio's early so that bio based drivers without flush
830 * support don't have to worry about them.
832 if (op_is_flush(bio
->bi_opf
) &&
833 !test_bit(QUEUE_FLAG_WC
, &q
->queue_flags
)) {
834 bio
->bi_opf
&= ~(REQ_PREFLUSH
| REQ_FUA
);
835 if (!bio_sectors(bio
)) {
841 if (!test_bit(QUEUE_FLAG_POLL
, &q
->queue_flags
))
842 bio_clear_hipri(bio
);
844 switch (bio_op(bio
)) {
846 if (!blk_queue_discard(q
))
849 case REQ_OP_SECURE_ERASE
:
850 if (!blk_queue_secure_erase(q
))
853 case REQ_OP_WRITE_SAME
:
854 if (!q
->limits
.max_write_same_sectors
)
857 case REQ_OP_ZONE_APPEND
:
858 status
= blk_check_zone_append(q
, bio
);
859 if (status
!= BLK_STS_OK
)
862 case REQ_OP_ZONE_RESET
:
863 case REQ_OP_ZONE_OPEN
:
864 case REQ_OP_ZONE_CLOSE
:
865 case REQ_OP_ZONE_FINISH
:
866 if (!blk_queue_is_zoned(q
))
869 case REQ_OP_ZONE_RESET_ALL
:
870 if (!blk_queue_is_zoned(q
) || !blk_queue_zone_resetall(q
))
873 case REQ_OP_WRITE_ZEROES
:
874 if (!q
->limits
.max_write_zeroes_sectors
)
882 * Various block parts want %current->io_context, so allocate it up
883 * front rather than dealing with lots of pain to allocate it only
884 * where needed. This may fail and the block layer knows how to live
887 if (unlikely(!current
->io_context
))
888 create_task_io_context(current
, GFP_ATOMIC
, q
->node
);
890 if (blk_throtl_bio(bio
)) {
891 blkcg_bio_issue_init(bio
);
895 blk_cgroup_bio_start(bio
);
896 blkcg_bio_issue_init(bio
);
898 if (!bio_flagged(bio
, BIO_TRACE_COMPLETION
)) {
899 trace_block_bio_queue(bio
);
900 /* Now that enqueuing has been traced, we need to trace
901 * completion as well.
903 bio_set_flag(bio
, BIO_TRACE_COMPLETION
);
908 status
= BLK_STS_NOTSUPP
;
910 bio
->bi_status
= status
;
915 static blk_qc_t
__submit_bio(struct bio
*bio
)
917 struct gendisk
*disk
= bio
->bi_bdev
->bd_disk
;
918 blk_qc_t ret
= BLK_QC_T_NONE
;
920 if (unlikely(bio_queue_enter(bio
) != 0))
921 return BLK_QC_T_NONE
;
923 if (!submit_bio_checks(bio
) || !blk_crypto_bio_prep(&bio
))
925 if (disk
->fops
->submit_bio
) {
926 ret
= disk
->fops
->submit_bio(bio
);
929 return blk_mq_submit_bio(bio
);
932 blk_queue_exit(disk
->queue
);
937 * The loop in this function may be a bit non-obvious, and so deserves some
940 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure
941 * that), so we have a list with a single bio.
942 * - We pretend that we have just taken it off a longer list, so we assign
943 * bio_list to a pointer to the bio_list_on_stack, thus initialising the
944 * bio_list of new bios to be added. ->submit_bio() may indeed add some more
945 * bios through a recursive call to submit_bio_noacct. If it did, we find a
946 * non-NULL value in bio_list and re-enter the loop from the top.
947 * - In this case we really did just take the bio of the top of the list (no
948 * pretending) and so remove it from bio_list, and call into ->submit_bio()
951 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
952 * bio_list_on_stack[1] contains bios that were submitted before the current
953 * ->submit_bio_bio, but that haven't been processed yet.
955 static blk_qc_t
__submit_bio_noacct(struct bio
*bio
)
957 struct bio_list bio_list_on_stack
[2];
958 blk_qc_t ret
= BLK_QC_T_NONE
;
960 BUG_ON(bio
->bi_next
);
962 bio_list_init(&bio_list_on_stack
[0]);
963 current
->bio_list
= bio_list_on_stack
;
966 struct request_queue
*q
= bio
->bi_bdev
->bd_disk
->queue
;
967 struct bio_list lower
, same
;
970 * Create a fresh bio_list for all subordinate requests.
972 bio_list_on_stack
[1] = bio_list_on_stack
[0];
973 bio_list_init(&bio_list_on_stack
[0]);
975 ret
= __submit_bio(bio
);
978 * Sort new bios into those for a lower level and those for the
981 bio_list_init(&lower
);
982 bio_list_init(&same
);
983 while ((bio
= bio_list_pop(&bio_list_on_stack
[0])) != NULL
)
984 if (q
== bio
->bi_bdev
->bd_disk
->queue
)
985 bio_list_add(&same
, bio
);
987 bio_list_add(&lower
, bio
);
990 * Now assemble so we handle the lowest level first.
992 bio_list_merge(&bio_list_on_stack
[0], &lower
);
993 bio_list_merge(&bio_list_on_stack
[0], &same
);
994 bio_list_merge(&bio_list_on_stack
[0], &bio_list_on_stack
[1]);
995 } while ((bio
= bio_list_pop(&bio_list_on_stack
[0])));
997 current
->bio_list
= NULL
;
1001 static blk_qc_t
__submit_bio_noacct_mq(struct bio
*bio
)
1003 struct bio_list bio_list
[2] = { };
1006 current
->bio_list
= bio_list
;
1009 ret
= __submit_bio(bio
);
1010 } while ((bio
= bio_list_pop(&bio_list
[0])));
1012 current
->bio_list
= NULL
;
1017 * submit_bio_noacct - re-submit a bio to the block device layer for I/O
1018 * @bio: The bio describing the location in memory and on the device.
1020 * This is a version of submit_bio() that shall only be used for I/O that is
1021 * resubmitted to lower level drivers by stacking block drivers. All file
1022 * systems and other upper level users of the block layer should use
1023 * submit_bio() instead.
1025 blk_qc_t
submit_bio_noacct(struct bio
*bio
)
1028 * We only want one ->submit_bio to be active at a time, else stack
1029 * usage with stacked devices could be a problem. Use current->bio_list
1030 * to collect a list of requests submited by a ->submit_bio method while
1031 * it is active, and then process them after it returned.
1033 if (current
->bio_list
) {
1034 bio_list_add(¤t
->bio_list
[0], bio
);
1035 return BLK_QC_T_NONE
;
1038 if (!bio
->bi_bdev
->bd_disk
->fops
->submit_bio
)
1039 return __submit_bio_noacct_mq(bio
);
1040 return __submit_bio_noacct(bio
);
1042 EXPORT_SYMBOL(submit_bio_noacct
);
1045 * submit_bio - submit a bio to the block device layer for I/O
1046 * @bio: The &struct bio which describes the I/O
1048 * submit_bio() is used to submit I/O requests to block devices. It is passed a
1049 * fully set up &struct bio that describes the I/O that needs to be done. The
1050 * bio will be send to the device described by the bi_bdev field.
1052 * The success/failure status of the request, along with notification of
1053 * completion, is delivered asynchronously through the ->bi_end_io() callback
1054 * in @bio. The bio must NOT be touched by thecaller until ->bi_end_io() has
1057 blk_qc_t
submit_bio(struct bio
*bio
)
1059 if (blkcg_punt_bio_submit(bio
))
1060 return BLK_QC_T_NONE
;
1063 * If it's a regular read/write or a barrier with data attached,
1064 * go through the normal accounting stuff before submission.
1066 if (bio_has_data(bio
)) {
1069 if (unlikely(bio_op(bio
) == REQ_OP_WRITE_SAME
))
1070 count
= queue_logical_block_size(
1071 bio
->bi_bdev
->bd_disk
->queue
) >> 9;
1073 count
= bio_sectors(bio
);
1075 if (op_is_write(bio_op(bio
))) {
1076 count_vm_events(PGPGOUT
, count
);
1078 task_io_account_read(bio
->bi_iter
.bi_size
);
1079 count_vm_events(PGPGIN
, count
);
1084 * If we're reading data that is part of the userspace workingset, count
1085 * submission time as memory stall. When the device is congested, or
1086 * the submitting cgroup IO-throttled, submission can be a significant
1087 * part of overall IO time.
1089 if (unlikely(bio_op(bio
) == REQ_OP_READ
&&
1090 bio_flagged(bio
, BIO_WORKINGSET
))) {
1091 unsigned long pflags
;
1094 psi_memstall_enter(&pflags
);
1095 ret
= submit_bio_noacct(bio
);
1096 psi_memstall_leave(&pflags
);
1101 return submit_bio_noacct(bio
);
1103 EXPORT_SYMBOL(submit_bio
);
1106 * blk_cloned_rq_check_limits - Helper function to check a cloned request
1107 * for the new queue limits
1109 * @rq: the request being checked
1112 * @rq may have been made based on weaker limitations of upper-level queues
1113 * in request stacking drivers, and it may violate the limitation of @q.
1114 * Since the block layer and the underlying device driver trust @rq
1115 * after it is inserted to @q, it should be checked against @q before
1116 * the insertion using this generic function.
1118 * Request stacking drivers like request-based dm may change the queue
1119 * limits when retrying requests on other queues. Those requests need
1120 * to be checked against the new queue limits again during dispatch.
1122 static blk_status_t
blk_cloned_rq_check_limits(struct request_queue
*q
,
1125 unsigned int max_sectors
= blk_queue_get_max_sectors(q
, req_op(rq
));
1127 if (blk_rq_sectors(rq
) > max_sectors
) {
1129 * SCSI device does not have a good way to return if
1130 * Write Same/Zero is actually supported. If a device rejects
1131 * a non-read/write command (discard, write same,etc.) the
1132 * low-level device driver will set the relevant queue limit to
1133 * 0 to prevent blk-lib from issuing more of the offending
1134 * operations. Commands queued prior to the queue limit being
1135 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
1136 * errors being propagated to upper layers.
1138 if (max_sectors
== 0)
1139 return BLK_STS_NOTSUPP
;
1141 printk(KERN_ERR
"%s: over max size limit. (%u > %u)\n",
1142 __func__
, blk_rq_sectors(rq
), max_sectors
);
1143 return BLK_STS_IOERR
;
1147 * The queue settings related to segment counting may differ from the
1150 rq
->nr_phys_segments
= blk_recalc_rq_segments(rq
);
1151 if (rq
->nr_phys_segments
> queue_max_segments(q
)) {
1152 printk(KERN_ERR
"%s: over max segments limit. (%hu > %hu)\n",
1153 __func__
, rq
->nr_phys_segments
, queue_max_segments(q
));
1154 return BLK_STS_IOERR
;
1161 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
1162 * @q: the queue to submit the request
1163 * @rq: the request being queued
1165 blk_status_t
blk_insert_cloned_request(struct request_queue
*q
, struct request
*rq
)
1169 ret
= blk_cloned_rq_check_limits(q
, rq
);
1170 if (ret
!= BLK_STS_OK
)
1174 should_fail_request(rq
->rq_disk
->part0
, blk_rq_bytes(rq
)))
1175 return BLK_STS_IOERR
;
1177 if (blk_crypto_insert_cloned_request(rq
))
1178 return BLK_STS_IOERR
;
1180 if (blk_queue_io_stat(q
))
1181 blk_account_io_start(rq
);
1184 * Since we have a scheduler attached on the top device,
1185 * bypass a potential scheduler on the bottom device for
1188 return blk_mq_request_issue_directly(rq
, true);
1190 EXPORT_SYMBOL_GPL(blk_insert_cloned_request
);
1193 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
1194 * @rq: request to examine
1197 * A request could be merge of IOs which require different failure
1198 * handling. This function determines the number of bytes which
1199 * can be failed from the beginning of the request without
1200 * crossing into area which need to be retried further.
1203 * The number of bytes to fail.
1205 unsigned int blk_rq_err_bytes(const struct request
*rq
)
1207 unsigned int ff
= rq
->cmd_flags
& REQ_FAILFAST_MASK
;
1208 unsigned int bytes
= 0;
1211 if (!(rq
->rq_flags
& RQF_MIXED_MERGE
))
1212 return blk_rq_bytes(rq
);
1215 * Currently the only 'mixing' which can happen is between
1216 * different fastfail types. We can safely fail portions
1217 * which have all the failfast bits that the first one has -
1218 * the ones which are at least as eager to fail as the first
1221 for (bio
= rq
->bio
; bio
; bio
= bio
->bi_next
) {
1222 if ((bio
->bi_opf
& ff
) != ff
)
1224 bytes
+= bio
->bi_iter
.bi_size
;
1227 /* this could lead to infinite loop */
1228 BUG_ON(blk_rq_bytes(rq
) && !bytes
);
1231 EXPORT_SYMBOL_GPL(blk_rq_err_bytes
);
1233 static void update_io_ticks(struct block_device
*part
, unsigned long now
,
1236 unsigned long stamp
;
1238 stamp
= READ_ONCE(part
->bd_stamp
);
1239 if (unlikely(time_after(now
, stamp
))) {
1240 if (likely(cmpxchg(&part
->bd_stamp
, stamp
, now
) == stamp
))
1241 __part_stat_add(part
, io_ticks
, end
? now
- stamp
: 1);
1243 if (part
->bd_partno
) {
1244 part
= bdev_whole(part
);
1249 static void blk_account_io_completion(struct request
*req
, unsigned int bytes
)
1251 if (req
->part
&& blk_do_io_stat(req
)) {
1252 const int sgrp
= op_stat_group(req_op(req
));
1255 part_stat_add(req
->part
, sectors
[sgrp
], bytes
>> 9);
1260 void blk_account_io_done(struct request
*req
, u64 now
)
1263 * Account IO completion. flush_rq isn't accounted as a
1264 * normal IO on queueing nor completion. Accounting the
1265 * containing request is enough.
1267 if (req
->part
&& blk_do_io_stat(req
) &&
1268 !(req
->rq_flags
& RQF_FLUSH_SEQ
)) {
1269 const int sgrp
= op_stat_group(req_op(req
));
1272 update_io_ticks(req
->part
, jiffies
, true);
1273 part_stat_inc(req
->part
, ios
[sgrp
]);
1274 part_stat_add(req
->part
, nsecs
[sgrp
], now
- req
->start_time_ns
);
1279 void blk_account_io_start(struct request
*rq
)
1281 if (!blk_do_io_stat(rq
))
1284 /* passthrough requests can hold bios that do not have ->bi_bdev set */
1285 if (rq
->bio
&& rq
->bio
->bi_bdev
)
1286 rq
->part
= rq
->bio
->bi_bdev
;
1288 rq
->part
= rq
->rq_disk
->part0
;
1291 update_io_ticks(rq
->part
, jiffies
, false);
1295 static unsigned long __part_start_io_acct(struct block_device
*part
,
1296 unsigned int sectors
, unsigned int op
)
1298 const int sgrp
= op_stat_group(op
);
1299 unsigned long now
= READ_ONCE(jiffies
);
1302 update_io_ticks(part
, now
, false);
1303 part_stat_inc(part
, ios
[sgrp
]);
1304 part_stat_add(part
, sectors
[sgrp
], sectors
);
1305 part_stat_local_inc(part
, in_flight
[op_is_write(op
)]);
1312 * bio_start_io_acct - start I/O accounting for bio based drivers
1313 * @bio: bio to start account for
1315 * Returns the start time that should be passed back to bio_end_io_acct().
1317 unsigned long bio_start_io_acct(struct bio
*bio
)
1319 return __part_start_io_acct(bio
->bi_bdev
, bio_sectors(bio
), bio_op(bio
));
1321 EXPORT_SYMBOL_GPL(bio_start_io_acct
);
1323 unsigned long disk_start_io_acct(struct gendisk
*disk
, unsigned int sectors
,
1326 return __part_start_io_acct(disk
->part0
, sectors
, op
);
1328 EXPORT_SYMBOL(disk_start_io_acct
);
1330 static void __part_end_io_acct(struct block_device
*part
, unsigned int op
,
1331 unsigned long start_time
)
1333 const int sgrp
= op_stat_group(op
);
1334 unsigned long now
= READ_ONCE(jiffies
);
1335 unsigned long duration
= now
- start_time
;
1338 update_io_ticks(part
, now
, true);
1339 part_stat_add(part
, nsecs
[sgrp
], jiffies_to_nsecs(duration
));
1340 part_stat_local_dec(part
, in_flight
[op_is_write(op
)]);
1344 void bio_end_io_acct_remapped(struct bio
*bio
, unsigned long start_time
,
1345 struct block_device
*orig_bdev
)
1347 __part_end_io_acct(orig_bdev
, bio_op(bio
), start_time
);
1349 EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped
);
1351 void disk_end_io_acct(struct gendisk
*disk
, unsigned int op
,
1352 unsigned long start_time
)
1354 __part_end_io_acct(disk
->part0
, op
, start_time
);
1356 EXPORT_SYMBOL(disk_end_io_acct
);
1359 * Steal bios from a request and add them to a bio list.
1360 * The request must not have been partially completed before.
1362 void blk_steal_bios(struct bio_list
*list
, struct request
*rq
)
1366 list
->tail
->bi_next
= rq
->bio
;
1368 list
->head
= rq
->bio
;
1369 list
->tail
= rq
->biotail
;
1377 EXPORT_SYMBOL_GPL(blk_steal_bios
);
1380 * blk_update_request - Complete multiple bytes without completing the request
1381 * @req: the request being processed
1382 * @error: block status code
1383 * @nr_bytes: number of bytes to complete for @req
1386 * Ends I/O on a number of bytes attached to @req, but doesn't complete
1387 * the request structure even if @req doesn't have leftover.
1388 * If @req has leftover, sets it up for the next range of segments.
1390 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
1391 * %false return from this function.
1394 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
1395 * except in the consistency check at the end of this function.
1398 * %false - this request doesn't have any more data
1399 * %true - this request has more data
1401 bool blk_update_request(struct request
*req
, blk_status_t error
,
1402 unsigned int nr_bytes
)
1406 trace_block_rq_complete(req
, blk_status_to_errno(error
), nr_bytes
);
1411 #ifdef CONFIG_BLK_DEV_INTEGRITY
1412 if (blk_integrity_rq(req
) && req_op(req
) == REQ_OP_READ
&&
1413 error
== BLK_STS_OK
)
1414 req
->q
->integrity
.profile
->complete_fn(req
, nr_bytes
);
1417 if (unlikely(error
&& !blk_rq_is_passthrough(req
) &&
1418 !(req
->rq_flags
& RQF_QUIET
)))
1419 print_req_error(req
, error
, __func__
);
1421 blk_account_io_completion(req
, nr_bytes
);
1425 struct bio
*bio
= req
->bio
;
1426 unsigned bio_bytes
= min(bio
->bi_iter
.bi_size
, nr_bytes
);
1428 if (bio_bytes
== bio
->bi_iter
.bi_size
)
1429 req
->bio
= bio
->bi_next
;
1431 /* Completion has already been traced */
1432 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
1433 req_bio_endio(req
, bio
, bio_bytes
, error
);
1435 total_bytes
+= bio_bytes
;
1436 nr_bytes
-= bio_bytes
;
1447 * Reset counters so that the request stacking driver
1448 * can find how many bytes remain in the request
1451 req
->__data_len
= 0;
1455 req
->__data_len
-= total_bytes
;
1457 /* update sector only for requests with clear definition of sector */
1458 if (!blk_rq_is_passthrough(req
))
1459 req
->__sector
+= total_bytes
>> 9;
1461 /* mixed attributes always follow the first bio */
1462 if (req
->rq_flags
& RQF_MIXED_MERGE
) {
1463 req
->cmd_flags
&= ~REQ_FAILFAST_MASK
;
1464 req
->cmd_flags
|= req
->bio
->bi_opf
& REQ_FAILFAST_MASK
;
1467 if (!(req
->rq_flags
& RQF_SPECIAL_PAYLOAD
)) {
1469 * If total number of sectors is less than the first segment
1470 * size, something has gone terribly wrong.
1472 if (blk_rq_bytes(req
) < blk_rq_cur_bytes(req
)) {
1473 blk_dump_rq_flags(req
, "request botched");
1474 req
->__data_len
= blk_rq_cur_bytes(req
);
1477 /* recalculate the number of segments */
1478 req
->nr_phys_segments
= blk_recalc_rq_segments(req
);
1483 EXPORT_SYMBOL_GPL(blk_update_request
);
1485 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1487 * rq_flush_dcache_pages - Helper function to flush all pages in a request
1488 * @rq: the request to be flushed
1491 * Flush all pages in @rq.
1493 void rq_flush_dcache_pages(struct request
*rq
)
1495 struct req_iterator iter
;
1496 struct bio_vec bvec
;
1498 rq_for_each_segment(bvec
, rq
, iter
)
1499 flush_dcache_page(bvec
.bv_page
);
1501 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages
);
1505 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
1506 * @q : the queue of the device being checked
1509 * Check if underlying low-level drivers of a device are busy.
1510 * If the drivers want to export their busy state, they must set own
1511 * exporting function using blk_queue_lld_busy() first.
1513 * Basically, this function is used only by request stacking drivers
1514 * to stop dispatching requests to underlying devices when underlying
1515 * devices are busy. This behavior helps more I/O merging on the queue
1516 * of the request stacking driver and prevents I/O throughput regression
1517 * on burst I/O load.
1520 * 0 - Not busy (The request stacking driver should dispatch request)
1521 * 1 - Busy (The request stacking driver should stop dispatching request)
1523 int blk_lld_busy(struct request_queue
*q
)
1525 if (queue_is_mq(q
) && q
->mq_ops
->busy
)
1526 return q
->mq_ops
->busy(q
);
1530 EXPORT_SYMBOL_GPL(blk_lld_busy
);
1533 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
1534 * @rq: the clone request to be cleaned up
1537 * Free all bios in @rq for a cloned request.
1539 void blk_rq_unprep_clone(struct request
*rq
)
1543 while ((bio
= rq
->bio
) != NULL
) {
1544 rq
->bio
= bio
->bi_next
;
1549 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone
);
1552 * blk_rq_prep_clone - Helper function to setup clone request
1553 * @rq: the request to be setup
1554 * @rq_src: original request to be cloned
1555 * @bs: bio_set that bios for clone are allocated from
1556 * @gfp_mask: memory allocation mask for bio
1557 * @bio_ctr: setup function to be called for each clone bio.
1558 * Returns %0 for success, non %0 for failure.
1559 * @data: private data to be passed to @bio_ctr
1562 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
1563 * Also, pages which the original bios are pointing to are not copied
1564 * and the cloned bios just point same pages.
1565 * So cloned bios must be completed before original bios, which means
1566 * the caller must complete @rq before @rq_src.
1568 int blk_rq_prep_clone(struct request
*rq
, struct request
*rq_src
,
1569 struct bio_set
*bs
, gfp_t gfp_mask
,
1570 int (*bio_ctr
)(struct bio
*, struct bio
*, void *),
1573 struct bio
*bio
, *bio_src
;
1578 __rq_for_each_bio(bio_src
, rq_src
) {
1579 bio
= bio_clone_fast(bio_src
, gfp_mask
, bs
);
1583 if (bio_ctr
&& bio_ctr(bio
, bio_src
, data
))
1587 rq
->biotail
->bi_next
= bio
;
1590 rq
->bio
= rq
->biotail
= bio
;
1595 /* Copy attributes of the original request to the clone request. */
1596 rq
->__sector
= blk_rq_pos(rq_src
);
1597 rq
->__data_len
= blk_rq_bytes(rq_src
);
1598 if (rq_src
->rq_flags
& RQF_SPECIAL_PAYLOAD
) {
1599 rq
->rq_flags
|= RQF_SPECIAL_PAYLOAD
;
1600 rq
->special_vec
= rq_src
->special_vec
;
1602 rq
->nr_phys_segments
= rq_src
->nr_phys_segments
;
1603 rq
->ioprio
= rq_src
->ioprio
;
1605 if (rq
->bio
&& blk_crypto_rq_bio_prep(rq
, rq
->bio
, gfp_mask
) < 0)
1613 blk_rq_unprep_clone(rq
);
1617 EXPORT_SYMBOL_GPL(blk_rq_prep_clone
);
1619 int kblockd_schedule_work(struct work_struct
*work
)
1621 return queue_work(kblockd_workqueue
, work
);
1623 EXPORT_SYMBOL(kblockd_schedule_work
);
1625 int kblockd_mod_delayed_work_on(int cpu
, struct delayed_work
*dwork
,
1626 unsigned long delay
)
1628 return mod_delayed_work_on(cpu
, kblockd_workqueue
, dwork
, delay
);
1630 EXPORT_SYMBOL(kblockd_mod_delayed_work_on
);
1633 * blk_start_plug - initialize blk_plug and track it inside the task_struct
1634 * @plug: The &struct blk_plug that needs to be initialized
1637 * blk_start_plug() indicates to the block layer an intent by the caller
1638 * to submit multiple I/O requests in a batch. The block layer may use
1639 * this hint to defer submitting I/Os from the caller until blk_finish_plug()
1640 * is called. However, the block layer may choose to submit requests
1641 * before a call to blk_finish_plug() if the number of queued I/Os
1642 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
1643 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
1644 * the task schedules (see below).
1646 * Tracking blk_plug inside the task_struct will help with auto-flushing the
1647 * pending I/O should the task end up blocking between blk_start_plug() and
1648 * blk_finish_plug(). This is important from a performance perspective, but
1649 * also ensures that we don't deadlock. For instance, if the task is blocking
1650 * for a memory allocation, memory reclaim could end up wanting to free a
1651 * page belonging to that request that is currently residing in our private
1652 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
1653 * this kind of deadlock.
1655 void blk_start_plug(struct blk_plug
*plug
)
1657 struct task_struct
*tsk
= current
;
1660 * If this is a nested plug, don't actually assign it.
1665 INIT_LIST_HEAD(&plug
->mq_list
);
1666 INIT_LIST_HEAD(&plug
->cb_list
);
1668 plug
->multiple_queues
= false;
1669 plug
->nowait
= false;
1672 * Store ordering should not be needed here, since a potential
1673 * preempt will imply a full memory barrier
1677 EXPORT_SYMBOL(blk_start_plug
);
1679 static void flush_plug_callbacks(struct blk_plug
*plug
, bool from_schedule
)
1681 LIST_HEAD(callbacks
);
1683 while (!list_empty(&plug
->cb_list
)) {
1684 list_splice_init(&plug
->cb_list
, &callbacks
);
1686 while (!list_empty(&callbacks
)) {
1687 struct blk_plug_cb
*cb
= list_first_entry(&callbacks
,
1690 list_del(&cb
->list
);
1691 cb
->callback(cb
, from_schedule
);
1696 struct blk_plug_cb
*blk_check_plugged(blk_plug_cb_fn unplug
, void *data
,
1699 struct blk_plug
*plug
= current
->plug
;
1700 struct blk_plug_cb
*cb
;
1705 list_for_each_entry(cb
, &plug
->cb_list
, list
)
1706 if (cb
->callback
== unplug
&& cb
->data
== data
)
1709 /* Not currently on the callback list */
1710 BUG_ON(size
< sizeof(*cb
));
1711 cb
= kzalloc(size
, GFP_ATOMIC
);
1714 cb
->callback
= unplug
;
1715 list_add(&cb
->list
, &plug
->cb_list
);
1719 EXPORT_SYMBOL(blk_check_plugged
);
1721 void blk_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1723 flush_plug_callbacks(plug
, from_schedule
);
1725 if (!list_empty(&plug
->mq_list
))
1726 blk_mq_flush_plug_list(plug
, from_schedule
);
1730 * blk_finish_plug - mark the end of a batch of submitted I/O
1731 * @plug: The &struct blk_plug passed to blk_start_plug()
1734 * Indicate that a batch of I/O submissions is complete. This function
1735 * must be paired with an initial call to blk_start_plug(). The intent
1736 * is to allow the block layer to optimize I/O submission. See the
1737 * documentation for blk_start_plug() for more information.
1739 void blk_finish_plug(struct blk_plug
*plug
)
1741 if (plug
!= current
->plug
)
1743 blk_flush_plug_list(plug
, false);
1745 current
->plug
= NULL
;
1747 EXPORT_SYMBOL(blk_finish_plug
);
1749 void blk_io_schedule(void)
1751 /* Prevent hang_check timer from firing at us during very long I/O */
1752 unsigned long timeout
= sysctl_hung_task_timeout_secs
* HZ
/ 2;
1755 io_schedule_timeout(timeout
);
1759 EXPORT_SYMBOL_GPL(blk_io_schedule
);
1761 int __init
blk_dev_init(void)
1763 BUILD_BUG_ON(REQ_OP_LAST
>= (1 << REQ_OP_BITS
));
1764 BUILD_BUG_ON(REQ_OP_BITS
+ REQ_FLAG_BITS
> 8 *
1765 sizeof_field(struct request
, cmd_flags
));
1766 BUILD_BUG_ON(REQ_OP_BITS
+ REQ_FLAG_BITS
> 8 *
1767 sizeof_field(struct bio
, bi_opf
));
1769 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
1770 kblockd_workqueue
= alloc_workqueue("kblockd",
1771 WQ_MEM_RECLAIM
| WQ_HIGHPRI
, 0);
1772 if (!kblockd_workqueue
)
1773 panic("Failed to create kblockd\n");
1775 blk_requestq_cachep
= kmem_cache_create("request_queue",
1776 sizeof(struct request_queue
), 0, SLAB_PANIC
, NULL
);
1778 blk_debugfs_root
= debugfs_create_dir("block", NULL
);