2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics
4 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
6 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
8 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
12 * This handles all read/write requests to block devices
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/backing-dev.h>
17 #include <linux/bio.h>
18 #include <linux/blkdev.h>
19 #include <linux/blk-mq.h>
20 #include <linux/highmem.h>
22 #include <linux/kernel_stat.h>
23 #include <linux/string.h>
24 #include <linux/init.h>
25 #include <linux/completion.h>
26 #include <linux/slab.h>
27 #include <linux/swap.h>
28 #include <linux/writeback.h>
29 #include <linux/task_io_accounting_ops.h>
30 #include <linux/fault-inject.h>
31 #include <linux/list_sort.h>
32 #include <linux/delay.h>
33 #include <linux/ratelimit.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/blk-cgroup.h>
36 #include <linux/debugfs.h>
37 #include <linux/bpf.h>
39 #define CREATE_TRACE_POINTS
40 #include <trace/events/block.h>
44 #include "blk-mq-sched.h"
47 #ifdef CONFIG_DEBUG_FS
48 struct dentry
*blk_debugfs_root
;
51 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap
);
52 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap
);
53 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete
);
54 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split
);
55 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug
);
57 DEFINE_IDA(blk_queue_ida
);
60 * For the allocated request tables
62 struct kmem_cache
*request_cachep
;
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
)
83 spin_lock_irqsave(q
->queue_lock
, flags
);
84 queue_flag_set(flag
, q
);
85 spin_unlock_irqrestore(q
->queue_lock
, flags
);
87 EXPORT_SYMBOL(blk_queue_flag_set
);
90 * blk_queue_flag_clear - atomically clear a queue flag
91 * @flag: flag to be cleared
94 void blk_queue_flag_clear(unsigned int flag
, struct request_queue
*q
)
98 spin_lock_irqsave(q
->queue_lock
, flags
);
99 queue_flag_clear(flag
, q
);
100 spin_unlock_irqrestore(q
->queue_lock
, flags
);
102 EXPORT_SYMBOL(blk_queue_flag_clear
);
105 * blk_queue_flag_test_and_set - atomically test and set a queue flag
106 * @flag: flag to be set
109 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
110 * the flag was already set.
112 bool blk_queue_flag_test_and_set(unsigned int flag
, struct request_queue
*q
)
117 spin_lock_irqsave(q
->queue_lock
, flags
);
118 res
= queue_flag_test_and_set(flag
, q
);
119 spin_unlock_irqrestore(q
->queue_lock
, flags
);
123 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set
);
126 * blk_queue_flag_test_and_clear - atomically test and clear a queue flag
127 * @flag: flag to be cleared
130 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
133 bool blk_queue_flag_test_and_clear(unsigned int flag
, struct request_queue
*q
)
138 spin_lock_irqsave(q
->queue_lock
, flags
);
139 res
= queue_flag_test_and_clear(flag
, q
);
140 spin_unlock_irqrestore(q
->queue_lock
, flags
);
144 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_clear
);
146 static void blk_clear_congested(struct request_list
*rl
, int sync
)
148 #ifdef CONFIG_CGROUP_WRITEBACK
149 clear_wb_congested(rl
->blkg
->wb_congested
, sync
);
152 * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
153 * flip its congestion state for events on other blkcgs.
155 if (rl
== &rl
->q
->root_rl
)
156 clear_wb_congested(rl
->q
->backing_dev_info
->wb
.congested
, sync
);
160 static void blk_set_congested(struct request_list
*rl
, int sync
)
162 #ifdef CONFIG_CGROUP_WRITEBACK
163 set_wb_congested(rl
->blkg
->wb_congested
, sync
);
165 /* see blk_clear_congested() */
166 if (rl
== &rl
->q
->root_rl
)
167 set_wb_congested(rl
->q
->backing_dev_info
->wb
.congested
, sync
);
171 void blk_queue_congestion_threshold(struct request_queue
*q
)
175 nr
= q
->nr_requests
- (q
->nr_requests
/ 8) + 1;
176 if (nr
> q
->nr_requests
)
178 q
->nr_congestion_on
= nr
;
180 nr
= q
->nr_requests
- (q
->nr_requests
/ 8) - (q
->nr_requests
/ 16) - 1;
183 q
->nr_congestion_off
= nr
;
186 void blk_rq_init(struct request_queue
*q
, struct request
*rq
)
188 memset(rq
, 0, sizeof(*rq
));
190 INIT_LIST_HEAD(&rq
->queuelist
);
191 INIT_LIST_HEAD(&rq
->timeout_list
);
194 rq
->__sector
= (sector_t
) -1;
195 INIT_HLIST_NODE(&rq
->hash
);
196 RB_CLEAR_NODE(&rq
->rb_node
);
198 rq
->internal_tag
= -1;
199 rq
->start_time
= jiffies
;
200 set_start_time_ns(rq
);
202 seqcount_init(&rq
->gstate_seq
);
203 u64_stats_init(&rq
->aborted_gstate_sync
);
205 EXPORT_SYMBOL(blk_rq_init
);
207 static const struct {
211 [BLK_STS_OK
] = { 0, "" },
212 [BLK_STS_NOTSUPP
] = { -EOPNOTSUPP
, "operation not supported" },
213 [BLK_STS_TIMEOUT
] = { -ETIMEDOUT
, "timeout" },
214 [BLK_STS_NOSPC
] = { -ENOSPC
, "critical space allocation" },
215 [BLK_STS_TRANSPORT
] = { -ENOLINK
, "recoverable transport" },
216 [BLK_STS_TARGET
] = { -EREMOTEIO
, "critical target" },
217 [BLK_STS_NEXUS
] = { -EBADE
, "critical nexus" },
218 [BLK_STS_MEDIUM
] = { -ENODATA
, "critical medium" },
219 [BLK_STS_PROTECTION
] = { -EILSEQ
, "protection" },
220 [BLK_STS_RESOURCE
] = { -ENOMEM
, "kernel resource" },
221 [BLK_STS_DEV_RESOURCE
] = { -EBUSY
, "device resource" },
222 [BLK_STS_AGAIN
] = { -EAGAIN
, "nonblocking retry" },
224 /* device mapper special case, should not leak out: */
225 [BLK_STS_DM_REQUEUE
] = { -EREMCHG
, "dm internal retry" },
227 /* everything else not covered above: */
228 [BLK_STS_IOERR
] = { -EIO
, "I/O" },
231 blk_status_t
errno_to_blk_status(int errno
)
235 for (i
= 0; i
< ARRAY_SIZE(blk_errors
); i
++) {
236 if (blk_errors
[i
].errno
== errno
)
237 return (__force blk_status_t
)i
;
240 return BLK_STS_IOERR
;
242 EXPORT_SYMBOL_GPL(errno_to_blk_status
);
244 int blk_status_to_errno(blk_status_t status
)
246 int idx
= (__force
int)status
;
248 if (WARN_ON_ONCE(idx
>= ARRAY_SIZE(blk_errors
)))
250 return blk_errors
[idx
].errno
;
252 EXPORT_SYMBOL_GPL(blk_status_to_errno
);
254 static void print_req_error(struct request
*req
, blk_status_t status
)
256 int idx
= (__force
int)status
;
258 if (WARN_ON_ONCE(idx
>= ARRAY_SIZE(blk_errors
)))
261 printk_ratelimited(KERN_ERR
"%s: %s error, dev %s, sector %llu\n",
262 __func__
, blk_errors
[idx
].name
, req
->rq_disk
?
263 req
->rq_disk
->disk_name
: "?",
264 (unsigned long long)blk_rq_pos(req
));
267 static void req_bio_endio(struct request
*rq
, struct bio
*bio
,
268 unsigned int nbytes
, blk_status_t error
)
271 bio
->bi_status
= error
;
273 if (unlikely(rq
->rq_flags
& RQF_QUIET
))
274 bio_set_flag(bio
, BIO_QUIET
);
276 bio_advance(bio
, nbytes
);
278 /* don't actually finish bio if it's part of flush sequence */
279 if (bio
->bi_iter
.bi_size
== 0 && !(rq
->rq_flags
& RQF_FLUSH_SEQ
))
283 void blk_dump_rq_flags(struct request
*rq
, char *msg
)
285 printk(KERN_INFO
"%s: dev %s: flags=%llx\n", msg
,
286 rq
->rq_disk
? rq
->rq_disk
->disk_name
: "?",
287 (unsigned long long) rq
->cmd_flags
);
289 printk(KERN_INFO
" sector %llu, nr/cnr %u/%u\n",
290 (unsigned long long)blk_rq_pos(rq
),
291 blk_rq_sectors(rq
), blk_rq_cur_sectors(rq
));
292 printk(KERN_INFO
" bio %p, biotail %p, len %u\n",
293 rq
->bio
, rq
->biotail
, blk_rq_bytes(rq
));
295 EXPORT_SYMBOL(blk_dump_rq_flags
);
297 static void blk_delay_work(struct work_struct
*work
)
299 struct request_queue
*q
;
301 q
= container_of(work
, struct request_queue
, delay_work
.work
);
302 spin_lock_irq(q
->queue_lock
);
304 spin_unlock_irq(q
->queue_lock
);
308 * blk_delay_queue - restart queueing after defined interval
309 * @q: The &struct request_queue in question
310 * @msecs: Delay in msecs
313 * Sometimes queueing needs to be postponed for a little while, to allow
314 * resources to come back. This function will make sure that queueing is
315 * restarted around the specified time.
317 void blk_delay_queue(struct request_queue
*q
, unsigned long msecs
)
319 lockdep_assert_held(q
->queue_lock
);
320 WARN_ON_ONCE(q
->mq_ops
);
322 if (likely(!blk_queue_dead(q
)))
323 queue_delayed_work(kblockd_workqueue
, &q
->delay_work
,
324 msecs_to_jiffies(msecs
));
326 EXPORT_SYMBOL(blk_delay_queue
);
329 * blk_start_queue_async - asynchronously restart a previously stopped queue
330 * @q: The &struct request_queue in question
333 * blk_start_queue_async() will clear the stop flag on the queue, and
334 * ensure that the request_fn for the queue is run from an async
337 void blk_start_queue_async(struct request_queue
*q
)
339 lockdep_assert_held(q
->queue_lock
);
340 WARN_ON_ONCE(q
->mq_ops
);
342 queue_flag_clear(QUEUE_FLAG_STOPPED
, q
);
343 blk_run_queue_async(q
);
345 EXPORT_SYMBOL(blk_start_queue_async
);
348 * blk_start_queue - restart a previously stopped queue
349 * @q: The &struct request_queue in question
352 * blk_start_queue() will clear the stop flag on the queue, and call
353 * the request_fn for the queue if it was in a stopped state when
354 * entered. Also see blk_stop_queue().
356 void blk_start_queue(struct request_queue
*q
)
358 lockdep_assert_held(q
->queue_lock
);
359 WARN_ON(!in_interrupt() && !irqs_disabled());
360 WARN_ON_ONCE(q
->mq_ops
);
362 queue_flag_clear(QUEUE_FLAG_STOPPED
, q
);
365 EXPORT_SYMBOL(blk_start_queue
);
368 * blk_stop_queue - stop a queue
369 * @q: The &struct request_queue in question
372 * The Linux block layer assumes that a block driver will consume all
373 * entries on the request queue when the request_fn strategy is called.
374 * Often this will not happen, because of hardware limitations (queue
375 * depth settings). If a device driver gets a 'queue full' response,
376 * or if it simply chooses not to queue more I/O at one point, it can
377 * call this function to prevent the request_fn from being called until
378 * the driver has signalled it's ready to go again. This happens by calling
379 * blk_start_queue() to restart queue operations.
381 void blk_stop_queue(struct request_queue
*q
)
383 lockdep_assert_held(q
->queue_lock
);
384 WARN_ON_ONCE(q
->mq_ops
);
386 cancel_delayed_work(&q
->delay_work
);
387 queue_flag_set(QUEUE_FLAG_STOPPED
, q
);
389 EXPORT_SYMBOL(blk_stop_queue
);
392 * blk_sync_queue - cancel any pending callbacks on a queue
396 * The block layer may perform asynchronous callback activity
397 * on a queue, such as calling the unplug function after a timeout.
398 * A block device may call blk_sync_queue to ensure that any
399 * such activity is cancelled, thus allowing it to release resources
400 * that the callbacks might use. The caller must already have made sure
401 * that its ->make_request_fn will not re-add plugging prior to calling
404 * This function does not cancel any asynchronous activity arising
405 * out of elevator or throttling code. That would require elevator_exit()
406 * and blkcg_exit_queue() to be called with queue lock initialized.
409 void blk_sync_queue(struct request_queue
*q
)
411 del_timer_sync(&q
->timeout
);
412 cancel_work_sync(&q
->timeout_work
);
415 struct blk_mq_hw_ctx
*hctx
;
418 cancel_delayed_work_sync(&q
->requeue_work
);
419 queue_for_each_hw_ctx(q
, hctx
, i
)
420 cancel_delayed_work_sync(&hctx
->run_work
);
422 cancel_delayed_work_sync(&q
->delay_work
);
425 EXPORT_SYMBOL(blk_sync_queue
);
428 * blk_set_preempt_only - set QUEUE_FLAG_PREEMPT_ONLY
429 * @q: request queue pointer
431 * Returns the previous value of the PREEMPT_ONLY flag - 0 if the flag was not
432 * set and 1 if the flag was already set.
434 int blk_set_preempt_only(struct request_queue
*q
)
436 return blk_queue_flag_test_and_set(QUEUE_FLAG_PREEMPT_ONLY
, q
);
438 EXPORT_SYMBOL_GPL(blk_set_preempt_only
);
440 void blk_clear_preempt_only(struct request_queue
*q
)
442 blk_queue_flag_clear(QUEUE_FLAG_PREEMPT_ONLY
, q
);
443 wake_up_all(&q
->mq_freeze_wq
);
445 EXPORT_SYMBOL_GPL(blk_clear_preempt_only
);
448 * __blk_run_queue_uncond - run a queue whether or not it has been stopped
449 * @q: The queue to run
452 * Invoke request handling on a queue if there are any pending requests.
453 * May be used to restart request handling after a request has completed.
454 * This variant runs the queue whether or not the queue has been
455 * stopped. Must be called with the queue lock held and interrupts
456 * disabled. See also @blk_run_queue.
458 inline void __blk_run_queue_uncond(struct request_queue
*q
)
460 lockdep_assert_held(q
->queue_lock
);
461 WARN_ON_ONCE(q
->mq_ops
);
463 if (unlikely(blk_queue_dead(q
)))
467 * Some request_fn implementations, e.g. scsi_request_fn(), unlock
468 * the queue lock internally. As a result multiple threads may be
469 * running such a request function concurrently. Keep track of the
470 * number of active request_fn invocations such that blk_drain_queue()
471 * can wait until all these request_fn calls have finished.
473 q
->request_fn_active
++;
475 q
->request_fn_active
--;
477 EXPORT_SYMBOL_GPL(__blk_run_queue_uncond
);
480 * __blk_run_queue - run a single device queue
481 * @q: The queue to run
484 * See @blk_run_queue.
486 void __blk_run_queue(struct request_queue
*q
)
488 lockdep_assert_held(q
->queue_lock
);
489 WARN_ON_ONCE(q
->mq_ops
);
491 if (unlikely(blk_queue_stopped(q
)))
494 __blk_run_queue_uncond(q
);
496 EXPORT_SYMBOL(__blk_run_queue
);
499 * blk_run_queue_async - run a single device queue in workqueue context
500 * @q: The queue to run
503 * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
507 * Since it is not allowed to run q->delay_work after blk_cleanup_queue()
508 * has canceled q->delay_work, callers must hold the queue lock to avoid
509 * race conditions between blk_cleanup_queue() and blk_run_queue_async().
511 void blk_run_queue_async(struct request_queue
*q
)
513 lockdep_assert_held(q
->queue_lock
);
514 WARN_ON_ONCE(q
->mq_ops
);
516 if (likely(!blk_queue_stopped(q
) && !blk_queue_dead(q
)))
517 mod_delayed_work(kblockd_workqueue
, &q
->delay_work
, 0);
519 EXPORT_SYMBOL(blk_run_queue_async
);
522 * blk_run_queue - run a single device queue
523 * @q: The queue to run
526 * Invoke request handling on this queue, if it has pending work to do.
527 * May be used to restart queueing when a request has completed.
529 void blk_run_queue(struct request_queue
*q
)
533 WARN_ON_ONCE(q
->mq_ops
);
535 spin_lock_irqsave(q
->queue_lock
, flags
);
537 spin_unlock_irqrestore(q
->queue_lock
, flags
);
539 EXPORT_SYMBOL(blk_run_queue
);
541 void blk_put_queue(struct request_queue
*q
)
543 kobject_put(&q
->kobj
);
545 EXPORT_SYMBOL(blk_put_queue
);
548 * __blk_drain_queue - drain requests from request_queue
550 * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
552 * Drain requests from @q. If @drain_all is set, all requests are drained.
553 * If not, only ELVPRIV requests are drained. The caller is responsible
554 * for ensuring that no new requests which need to be drained are queued.
556 static void __blk_drain_queue(struct request_queue
*q
, bool drain_all
)
557 __releases(q
->queue_lock
)
558 __acquires(q
->queue_lock
)
562 lockdep_assert_held(q
->queue_lock
);
563 WARN_ON_ONCE(q
->mq_ops
);
569 * The caller might be trying to drain @q before its
570 * elevator is initialized.
573 elv_drain_elevator(q
);
575 blkcg_drain_queue(q
);
578 * This function might be called on a queue which failed
579 * driver init after queue creation or is not yet fully
580 * active yet. Some drivers (e.g. fd and loop) get unhappy
581 * in such cases. Kick queue iff dispatch queue has
582 * something on it and @q has request_fn set.
584 if (!list_empty(&q
->queue_head
) && q
->request_fn
)
587 drain
|= q
->nr_rqs_elvpriv
;
588 drain
|= q
->request_fn_active
;
591 * Unfortunately, requests are queued at and tracked from
592 * multiple places and there's no single counter which can
593 * be drained. Check all the queues and counters.
596 struct blk_flush_queue
*fq
= blk_get_flush_queue(q
, NULL
);
597 drain
|= !list_empty(&q
->queue_head
);
598 for (i
= 0; i
< 2; i
++) {
599 drain
|= q
->nr_rqs
[i
];
600 drain
|= q
->in_flight
[i
];
602 drain
|= !list_empty(&fq
->flush_queue
[i
]);
609 spin_unlock_irq(q
->queue_lock
);
613 spin_lock_irq(q
->queue_lock
);
617 * With queue marked dead, any woken up waiter will fail the
618 * allocation path, so the wakeup chaining is lost and we're
619 * left with hung waiters. We need to wake up those waiters.
622 struct request_list
*rl
;
624 blk_queue_for_each_rl(rl
, q
)
625 for (i
= 0; i
< ARRAY_SIZE(rl
->wait
); i
++)
626 wake_up_all(&rl
->wait
[i
]);
630 void blk_drain_queue(struct request_queue
*q
)
632 spin_lock_irq(q
->queue_lock
);
633 __blk_drain_queue(q
, true);
634 spin_unlock_irq(q
->queue_lock
);
638 * blk_queue_bypass_start - enter queue bypass mode
639 * @q: queue of interest
641 * In bypass mode, only the dispatch FIFO queue of @q is used. This
642 * function makes @q enter bypass mode and drains all requests which were
643 * throttled or issued before. On return, it's guaranteed that no request
644 * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
645 * inside queue or RCU read lock.
647 void blk_queue_bypass_start(struct request_queue
*q
)
649 WARN_ON_ONCE(q
->mq_ops
);
651 spin_lock_irq(q
->queue_lock
);
653 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
654 spin_unlock_irq(q
->queue_lock
);
657 * Queues start drained. Skip actual draining till init is
658 * complete. This avoids lenghty delays during queue init which
659 * can happen many times during boot.
661 if (blk_queue_init_done(q
)) {
662 spin_lock_irq(q
->queue_lock
);
663 __blk_drain_queue(q
, false);
664 spin_unlock_irq(q
->queue_lock
);
666 /* ensure blk_queue_bypass() is %true inside RCU read lock */
670 EXPORT_SYMBOL_GPL(blk_queue_bypass_start
);
673 * blk_queue_bypass_end - leave queue bypass mode
674 * @q: queue of interest
676 * Leave bypass mode and restore the normal queueing behavior.
678 * Note: although blk_queue_bypass_start() is only called for blk-sq queues,
679 * this function is called for both blk-sq and blk-mq queues.
681 void blk_queue_bypass_end(struct request_queue
*q
)
683 spin_lock_irq(q
->queue_lock
);
684 if (!--q
->bypass_depth
)
685 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
686 WARN_ON_ONCE(q
->bypass_depth
< 0);
687 spin_unlock_irq(q
->queue_lock
);
689 EXPORT_SYMBOL_GPL(blk_queue_bypass_end
);
691 void blk_set_queue_dying(struct request_queue
*q
)
693 blk_queue_flag_set(QUEUE_FLAG_DYING
, q
);
696 * When queue DYING flag is set, we need to block new req
697 * entering queue, so we call blk_freeze_queue_start() to
698 * prevent I/O from crossing blk_queue_enter().
700 blk_freeze_queue_start(q
);
703 blk_mq_wake_waiters(q
);
705 struct request_list
*rl
;
707 spin_lock_irq(q
->queue_lock
);
708 blk_queue_for_each_rl(rl
, q
) {
710 wake_up_all(&rl
->wait
[BLK_RW_SYNC
]);
711 wake_up_all(&rl
->wait
[BLK_RW_ASYNC
]);
714 spin_unlock_irq(q
->queue_lock
);
717 /* Make blk_queue_enter() reexamine the DYING flag. */
718 wake_up_all(&q
->mq_freeze_wq
);
720 EXPORT_SYMBOL_GPL(blk_set_queue_dying
);
723 * blk_cleanup_queue - shutdown a request queue
724 * @q: request queue to shutdown
726 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
727 * put it. All future requests will be failed immediately with -ENODEV.
729 void blk_cleanup_queue(struct request_queue
*q
)
731 spinlock_t
*lock
= q
->queue_lock
;
733 /* mark @q DYING, no new request or merges will be allowed afterwards */
734 mutex_lock(&q
->sysfs_lock
);
735 blk_set_queue_dying(q
);
739 * A dying queue is permanently in bypass mode till released. Note
740 * that, unlike blk_queue_bypass_start(), we aren't performing
741 * synchronize_rcu() after entering bypass mode to avoid the delay
742 * as some drivers create and destroy a lot of queues while
743 * probing. This is still safe because blk_release_queue() will be
744 * called only after the queue refcnt drops to zero and nothing,
745 * RCU or not, would be traversing the queue by then.
748 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
750 queue_flag_set(QUEUE_FLAG_NOMERGES
, q
);
751 queue_flag_set(QUEUE_FLAG_NOXMERGES
, q
);
752 queue_flag_set(QUEUE_FLAG_DYING
, q
);
753 spin_unlock_irq(lock
);
754 mutex_unlock(&q
->sysfs_lock
);
757 * Drain all requests queued before DYING marking. Set DEAD flag to
758 * prevent that q->request_fn() gets invoked after draining finished.
762 queue_flag_set(QUEUE_FLAG_DEAD
, q
);
763 spin_unlock_irq(lock
);
766 * make sure all in-progress dispatch are completed because
767 * blk_freeze_queue() can only complete all requests, and
768 * dispatch may still be in-progress since we dispatch requests
769 * from more than one contexts
772 blk_mq_quiesce_queue(q
);
774 /* for synchronous bio-based driver finish in-flight integrity i/o */
775 blk_flush_integrity();
777 /* @q won't process any more request, flush async actions */
778 del_timer_sync(&q
->backing_dev_info
->laptop_mode_wb_timer
);
782 * I/O scheduler exit is only safe after the sysfs scheduler attribute
785 WARN_ON_ONCE(q
->kobj
.state_in_sysfs
);
788 * Since the I/O scheduler exit code may access cgroup information,
789 * perform I/O scheduler exit before disassociating from the block
794 elevator_exit(q
, q
->elevator
);
799 * Remove all references to @q from the block cgroup controller before
800 * restoring @q->queue_lock to avoid that restoring this pointer causes
801 * e.g. blkcg_print_blkgs() to crash.
806 * Since the cgroup code may dereference the @q->backing_dev_info
807 * pointer, only decrease its reference count after having removed the
808 * association with the block cgroup controller.
810 bdi_put(q
->backing_dev_info
);
813 blk_mq_free_queue(q
);
814 percpu_ref_exit(&q
->q_usage_counter
);
817 if (q
->queue_lock
!= &q
->__queue_lock
)
818 q
->queue_lock
= &q
->__queue_lock
;
819 spin_unlock_irq(lock
);
821 /* @q is and will stay empty, shutdown and put */
824 EXPORT_SYMBOL(blk_cleanup_queue
);
826 /* Allocate memory local to the request queue */
827 static void *alloc_request_simple(gfp_t gfp_mask
, void *data
)
829 struct request_queue
*q
= data
;
831 return kmem_cache_alloc_node(request_cachep
, gfp_mask
, q
->node
);
834 static void free_request_simple(void *element
, void *data
)
836 kmem_cache_free(request_cachep
, element
);
839 static void *alloc_request_size(gfp_t gfp_mask
, void *data
)
841 struct request_queue
*q
= data
;
844 rq
= kmalloc_node(sizeof(struct request
) + q
->cmd_size
, gfp_mask
,
846 if (rq
&& q
->init_rq_fn
&& q
->init_rq_fn(q
, rq
, gfp_mask
) < 0) {
853 static void free_request_size(void *element
, void *data
)
855 struct request_queue
*q
= data
;
858 q
->exit_rq_fn(q
, element
);
862 int blk_init_rl(struct request_list
*rl
, struct request_queue
*q
,
865 if (unlikely(rl
->rq_pool
) || q
->mq_ops
)
869 rl
->count
[BLK_RW_SYNC
] = rl
->count
[BLK_RW_ASYNC
] = 0;
870 rl
->starved
[BLK_RW_SYNC
] = rl
->starved
[BLK_RW_ASYNC
] = 0;
871 init_waitqueue_head(&rl
->wait
[BLK_RW_SYNC
]);
872 init_waitqueue_head(&rl
->wait
[BLK_RW_ASYNC
]);
875 rl
->rq_pool
= mempool_create_node(BLKDEV_MIN_RQ
,
876 alloc_request_size
, free_request_size
,
877 q
, gfp_mask
, q
->node
);
879 rl
->rq_pool
= mempool_create_node(BLKDEV_MIN_RQ
,
880 alloc_request_simple
, free_request_simple
,
881 q
, gfp_mask
, q
->node
);
886 if (rl
!= &q
->root_rl
)
887 WARN_ON_ONCE(!blk_get_queue(q
));
892 void blk_exit_rl(struct request_queue
*q
, struct request_list
*rl
)
895 mempool_destroy(rl
->rq_pool
);
896 if (rl
!= &q
->root_rl
)
901 struct request_queue
*blk_alloc_queue(gfp_t gfp_mask
)
903 return blk_alloc_queue_node(gfp_mask
, NUMA_NO_NODE
, NULL
);
905 EXPORT_SYMBOL(blk_alloc_queue
);
908 * blk_queue_enter() - try to increase q->q_usage_counter
909 * @q: request queue pointer
910 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PREEMPT
912 int blk_queue_enter(struct request_queue
*q
, blk_mq_req_flags_t flags
)
914 const bool preempt
= flags
& BLK_MQ_REQ_PREEMPT
;
917 bool success
= false;
921 if (percpu_ref_tryget_live(&q
->q_usage_counter
)) {
923 * The code that sets the PREEMPT_ONLY flag is
924 * responsible for ensuring that that flag is globally
925 * visible before the queue is unfrozen.
927 if (preempt
|| !blk_queue_preempt_only(q
)) {
930 percpu_ref_put(&q
->q_usage_counter
);
938 if (flags
& BLK_MQ_REQ_NOWAIT
)
942 * read pair of barrier in blk_freeze_queue_start(),
943 * we need to order reading __PERCPU_REF_DEAD flag of
944 * .q_usage_counter and reading .mq_freeze_depth or
945 * queue dying flag, otherwise the following wait may
946 * never return if the two reads are reordered.
950 ret
= wait_event_interruptible(q
->mq_freeze_wq
,
951 (atomic_read(&q
->mq_freeze_depth
) == 0 &&
952 (preempt
|| !blk_queue_preempt_only(q
))) ||
954 if (blk_queue_dying(q
))
961 void blk_queue_exit(struct request_queue
*q
)
963 percpu_ref_put(&q
->q_usage_counter
);
966 static void blk_queue_usage_counter_release(struct percpu_ref
*ref
)
968 struct request_queue
*q
=
969 container_of(ref
, struct request_queue
, q_usage_counter
);
971 wake_up_all(&q
->mq_freeze_wq
);
974 static void blk_rq_timed_out_timer(struct timer_list
*t
)
976 struct request_queue
*q
= from_timer(q
, t
, timeout
);
978 kblockd_schedule_work(&q
->timeout_work
);
982 * blk_alloc_queue_node - allocate a request queue
983 * @gfp_mask: memory allocation flags
984 * @node_id: NUMA node to allocate memory from
985 * @lock: For legacy queues, pointer to a spinlock that will be used to e.g.
986 * serialize calls to the legacy .request_fn() callback. Ignored for
987 * blk-mq request queues.
989 * Note: pass the queue lock as the third argument to this function instead of
990 * setting the queue lock pointer explicitly to avoid triggering a sporadic
991 * crash in the blkcg code. This function namely calls blkcg_init_queue() and
992 * the queue lock pointer must be set before blkcg_init_queue() is called.
994 struct request_queue
*blk_alloc_queue_node(gfp_t gfp_mask
, int node_id
,
997 struct request_queue
*q
;
999 q
= kmem_cache_alloc_node(blk_requestq_cachep
,
1000 gfp_mask
| __GFP_ZERO
, node_id
);
1004 q
->id
= ida_simple_get(&blk_queue_ida
, 0, 0, gfp_mask
);
1008 q
->bio_split
= bioset_create(BIO_POOL_SIZE
, 0, BIOSET_NEED_BVECS
);
1012 q
->backing_dev_info
= bdi_alloc_node(gfp_mask
, node_id
);
1013 if (!q
->backing_dev_info
)
1016 q
->stats
= blk_alloc_queue_stats();
1020 q
->backing_dev_info
->ra_pages
=
1021 (VM_MAX_READAHEAD
* 1024) / PAGE_SIZE
;
1022 q
->backing_dev_info
->capabilities
= BDI_CAP_CGROUP_WRITEBACK
;
1023 q
->backing_dev_info
->name
= "block";
1026 timer_setup(&q
->backing_dev_info
->laptop_mode_wb_timer
,
1027 laptop_mode_timer_fn
, 0);
1028 timer_setup(&q
->timeout
, blk_rq_timed_out_timer
, 0);
1029 INIT_WORK(&q
->timeout_work
, NULL
);
1030 INIT_LIST_HEAD(&q
->queue_head
);
1031 INIT_LIST_HEAD(&q
->timeout_list
);
1032 INIT_LIST_HEAD(&q
->icq_list
);
1033 #ifdef CONFIG_BLK_CGROUP
1034 INIT_LIST_HEAD(&q
->blkg_list
);
1036 INIT_DELAYED_WORK(&q
->delay_work
, blk_delay_work
);
1038 kobject_init(&q
->kobj
, &blk_queue_ktype
);
1040 #ifdef CONFIG_BLK_DEV_IO_TRACE
1041 mutex_init(&q
->blk_trace_mutex
);
1043 mutex_init(&q
->sysfs_lock
);
1044 spin_lock_init(&q
->__queue_lock
);
1047 q
->queue_lock
= lock
? : &q
->__queue_lock
;
1050 * A queue starts its life with bypass turned on to avoid
1051 * unnecessary bypass on/off overhead and nasty surprises during
1052 * init. The initial bypass will be finished when the queue is
1053 * registered by blk_register_queue().
1055 q
->bypass_depth
= 1;
1056 queue_flag_set_unlocked(QUEUE_FLAG_BYPASS
, q
);
1058 init_waitqueue_head(&q
->mq_freeze_wq
);
1061 * Init percpu_ref in atomic mode so that it's faster to shutdown.
1062 * See blk_register_queue() for details.
1064 if (percpu_ref_init(&q
->q_usage_counter
,
1065 blk_queue_usage_counter_release
,
1066 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
1069 if (blkcg_init_queue(q
))
1075 percpu_ref_exit(&q
->q_usage_counter
);
1077 blk_free_queue_stats(q
->stats
);
1079 bdi_put(q
->backing_dev_info
);
1081 bioset_free(q
->bio_split
);
1083 ida_simple_remove(&blk_queue_ida
, q
->id
);
1085 kmem_cache_free(blk_requestq_cachep
, q
);
1088 EXPORT_SYMBOL(blk_alloc_queue_node
);
1091 * blk_init_queue - prepare a request queue for use with a block device
1092 * @rfn: The function to be called to process requests that have been
1093 * placed on the queue.
1094 * @lock: Request queue spin lock
1097 * If a block device wishes to use the standard request handling procedures,
1098 * which sorts requests and coalesces adjacent requests, then it must
1099 * call blk_init_queue(). The function @rfn will be called when there
1100 * are requests on the queue that need to be processed. If the device
1101 * supports plugging, then @rfn may not be called immediately when requests
1102 * are available on the queue, but may be called at some time later instead.
1103 * Plugged queues are generally unplugged when a buffer belonging to one
1104 * of the requests on the queue is needed, or due to memory pressure.
1106 * @rfn is not required, or even expected, to remove all requests off the
1107 * queue, but only as many as it can handle at a time. If it does leave
1108 * requests on the queue, it is responsible for arranging that the requests
1109 * get dealt with eventually.
1111 * The queue spin lock must be held while manipulating the requests on the
1112 * request queue; this lock will be taken also from interrupt context, so irq
1113 * disabling is needed for it.
1115 * Function returns a pointer to the initialized request queue, or %NULL if
1116 * it didn't succeed.
1119 * blk_init_queue() must be paired with a blk_cleanup_queue() call
1120 * when the block device is deactivated (such as at module unload).
1123 struct request_queue
*blk_init_queue(request_fn_proc
*rfn
, spinlock_t
*lock
)
1125 return blk_init_queue_node(rfn
, lock
, NUMA_NO_NODE
);
1127 EXPORT_SYMBOL(blk_init_queue
);
1129 struct request_queue
*
1130 blk_init_queue_node(request_fn_proc
*rfn
, spinlock_t
*lock
, int node_id
)
1132 struct request_queue
*q
;
1134 q
= blk_alloc_queue_node(GFP_KERNEL
, node_id
, lock
);
1138 q
->request_fn
= rfn
;
1139 if (blk_init_allocated_queue(q
) < 0) {
1140 blk_cleanup_queue(q
);
1146 EXPORT_SYMBOL(blk_init_queue_node
);
1148 static blk_qc_t
blk_queue_bio(struct request_queue
*q
, struct bio
*bio
);
1151 int blk_init_allocated_queue(struct request_queue
*q
)
1153 WARN_ON_ONCE(q
->mq_ops
);
1155 q
->fq
= blk_alloc_flush_queue(q
, NUMA_NO_NODE
, q
->cmd_size
);
1159 if (q
->init_rq_fn
&& q
->init_rq_fn(q
, q
->fq
->flush_rq
, GFP_KERNEL
))
1160 goto out_free_flush_queue
;
1162 if (blk_init_rl(&q
->root_rl
, q
, GFP_KERNEL
))
1163 goto out_exit_flush_rq
;
1165 INIT_WORK(&q
->timeout_work
, blk_timeout_work
);
1166 q
->queue_flags
|= QUEUE_FLAG_DEFAULT
;
1169 * This also sets hw/phys segments, boundary and size
1171 blk_queue_make_request(q
, blk_queue_bio
);
1173 q
->sg_reserved_size
= INT_MAX
;
1175 /* Protect q->elevator from elevator_change */
1176 mutex_lock(&q
->sysfs_lock
);
1179 if (elevator_init(q
, NULL
)) {
1180 mutex_unlock(&q
->sysfs_lock
);
1181 goto out_exit_flush_rq
;
1184 mutex_unlock(&q
->sysfs_lock
);
1189 q
->exit_rq_fn(q
, q
->fq
->flush_rq
);
1190 out_free_flush_queue
:
1191 blk_free_flush_queue(q
->fq
);
1194 EXPORT_SYMBOL(blk_init_allocated_queue
);
1196 bool blk_get_queue(struct request_queue
*q
)
1198 if (likely(!blk_queue_dying(q
))) {
1205 EXPORT_SYMBOL(blk_get_queue
);
1207 static inline void blk_free_request(struct request_list
*rl
, struct request
*rq
)
1209 if (rq
->rq_flags
& RQF_ELVPRIV
) {
1210 elv_put_request(rl
->q
, rq
);
1212 put_io_context(rq
->elv
.icq
->ioc
);
1215 mempool_free(rq
, rl
->rq_pool
);
1219 * ioc_batching returns true if the ioc is a valid batching request and
1220 * should be given priority access to a request.
1222 static inline int ioc_batching(struct request_queue
*q
, struct io_context
*ioc
)
1228 * Make sure the process is able to allocate at least 1 request
1229 * even if the batch times out, otherwise we could theoretically
1232 return ioc
->nr_batch_requests
== q
->nr_batching
||
1233 (ioc
->nr_batch_requests
> 0
1234 && time_before(jiffies
, ioc
->last_waited
+ BLK_BATCH_TIME
));
1238 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
1239 * will cause the process to be a "batcher" on all queues in the system. This
1240 * is the behaviour we want though - once it gets a wakeup it should be given
1243 static void ioc_set_batching(struct request_queue
*q
, struct io_context
*ioc
)
1245 if (!ioc
|| ioc_batching(q
, ioc
))
1248 ioc
->nr_batch_requests
= q
->nr_batching
;
1249 ioc
->last_waited
= jiffies
;
1252 static void __freed_request(struct request_list
*rl
, int sync
)
1254 struct request_queue
*q
= rl
->q
;
1256 if (rl
->count
[sync
] < queue_congestion_off_threshold(q
))
1257 blk_clear_congested(rl
, sync
);
1259 if (rl
->count
[sync
] + 1 <= q
->nr_requests
) {
1260 if (waitqueue_active(&rl
->wait
[sync
]))
1261 wake_up(&rl
->wait
[sync
]);
1263 blk_clear_rl_full(rl
, sync
);
1268 * A request has just been released. Account for it, update the full and
1269 * congestion status, wake up any waiters. Called under q->queue_lock.
1271 static void freed_request(struct request_list
*rl
, bool sync
,
1272 req_flags_t rq_flags
)
1274 struct request_queue
*q
= rl
->q
;
1278 if (rq_flags
& RQF_ELVPRIV
)
1279 q
->nr_rqs_elvpriv
--;
1281 __freed_request(rl
, sync
);
1283 if (unlikely(rl
->starved
[sync
^ 1]))
1284 __freed_request(rl
, sync
^ 1);
1287 int blk_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
1289 struct request_list
*rl
;
1290 int on_thresh
, off_thresh
;
1292 WARN_ON_ONCE(q
->mq_ops
);
1294 spin_lock_irq(q
->queue_lock
);
1295 q
->nr_requests
= nr
;
1296 blk_queue_congestion_threshold(q
);
1297 on_thresh
= queue_congestion_on_threshold(q
);
1298 off_thresh
= queue_congestion_off_threshold(q
);
1300 blk_queue_for_each_rl(rl
, q
) {
1301 if (rl
->count
[BLK_RW_SYNC
] >= on_thresh
)
1302 blk_set_congested(rl
, BLK_RW_SYNC
);
1303 else if (rl
->count
[BLK_RW_SYNC
] < off_thresh
)
1304 blk_clear_congested(rl
, BLK_RW_SYNC
);
1306 if (rl
->count
[BLK_RW_ASYNC
] >= on_thresh
)
1307 blk_set_congested(rl
, BLK_RW_ASYNC
);
1308 else if (rl
->count
[BLK_RW_ASYNC
] < off_thresh
)
1309 blk_clear_congested(rl
, BLK_RW_ASYNC
);
1311 if (rl
->count
[BLK_RW_SYNC
] >= q
->nr_requests
) {
1312 blk_set_rl_full(rl
, BLK_RW_SYNC
);
1314 blk_clear_rl_full(rl
, BLK_RW_SYNC
);
1315 wake_up(&rl
->wait
[BLK_RW_SYNC
]);
1318 if (rl
->count
[BLK_RW_ASYNC
] >= q
->nr_requests
) {
1319 blk_set_rl_full(rl
, BLK_RW_ASYNC
);
1321 blk_clear_rl_full(rl
, BLK_RW_ASYNC
);
1322 wake_up(&rl
->wait
[BLK_RW_ASYNC
]);
1326 spin_unlock_irq(q
->queue_lock
);
1331 * __get_request - get a free request
1332 * @rl: request list to allocate from
1333 * @op: operation and flags
1334 * @bio: bio to allocate request for (can be %NULL)
1335 * @flags: BLQ_MQ_REQ_* flags
1337 * Get a free request from @q. This function may fail under memory
1338 * pressure or if @q is dead.
1340 * Must be called with @q->queue_lock held and,
1341 * Returns ERR_PTR on failure, with @q->queue_lock held.
1342 * Returns request pointer on success, with @q->queue_lock *not held*.
1344 static struct request
*__get_request(struct request_list
*rl
, unsigned int op
,
1345 struct bio
*bio
, blk_mq_req_flags_t flags
)
1347 struct request_queue
*q
= rl
->q
;
1349 struct elevator_type
*et
= q
->elevator
->type
;
1350 struct io_context
*ioc
= rq_ioc(bio
);
1351 struct io_cq
*icq
= NULL
;
1352 const bool is_sync
= op_is_sync(op
);
1354 gfp_t gfp_mask
= flags
& BLK_MQ_REQ_NOWAIT
? GFP_ATOMIC
:
1355 __GFP_DIRECT_RECLAIM
;
1356 req_flags_t rq_flags
= RQF_ALLOCED
;
1358 lockdep_assert_held(q
->queue_lock
);
1360 if (unlikely(blk_queue_dying(q
)))
1361 return ERR_PTR(-ENODEV
);
1363 may_queue
= elv_may_queue(q
, op
);
1364 if (may_queue
== ELV_MQUEUE_NO
)
1367 if (rl
->count
[is_sync
]+1 >= queue_congestion_on_threshold(q
)) {
1368 if (rl
->count
[is_sync
]+1 >= q
->nr_requests
) {
1370 * The queue will fill after this allocation, so set
1371 * it as full, and mark this process as "batching".
1372 * This process will be allowed to complete a batch of
1373 * requests, others will be blocked.
1375 if (!blk_rl_full(rl
, is_sync
)) {
1376 ioc_set_batching(q
, ioc
);
1377 blk_set_rl_full(rl
, is_sync
);
1379 if (may_queue
!= ELV_MQUEUE_MUST
1380 && !ioc_batching(q
, ioc
)) {
1382 * The queue is full and the allocating
1383 * process is not a "batcher", and not
1384 * exempted by the IO scheduler
1386 return ERR_PTR(-ENOMEM
);
1390 blk_set_congested(rl
, is_sync
);
1394 * Only allow batching queuers to allocate up to 50% over the defined
1395 * limit of requests, otherwise we could have thousands of requests
1396 * allocated with any setting of ->nr_requests
1398 if (rl
->count
[is_sync
] >= (3 * q
->nr_requests
/ 2))
1399 return ERR_PTR(-ENOMEM
);
1401 q
->nr_rqs
[is_sync
]++;
1402 rl
->count
[is_sync
]++;
1403 rl
->starved
[is_sync
] = 0;
1406 * Decide whether the new request will be managed by elevator. If
1407 * so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will
1408 * prevent the current elevator from being destroyed until the new
1409 * request is freed. This guarantees icq's won't be destroyed and
1410 * makes creating new ones safe.
1412 * Flush requests do not use the elevator so skip initialization.
1413 * This allows a request to share the flush and elevator data.
1415 * Also, lookup icq while holding queue_lock. If it doesn't exist,
1416 * it will be created after releasing queue_lock.
1418 if (!op_is_flush(op
) && !blk_queue_bypass(q
)) {
1419 rq_flags
|= RQF_ELVPRIV
;
1420 q
->nr_rqs_elvpriv
++;
1421 if (et
->icq_cache
&& ioc
)
1422 icq
= ioc_lookup_icq(ioc
, q
);
1425 if (blk_queue_io_stat(q
))
1426 rq_flags
|= RQF_IO_STAT
;
1427 spin_unlock_irq(q
->queue_lock
);
1429 /* allocate and init request */
1430 rq
= mempool_alloc(rl
->rq_pool
, gfp_mask
);
1435 blk_rq_set_rl(rq
, rl
);
1437 rq
->rq_flags
= rq_flags
;
1438 if (flags
& BLK_MQ_REQ_PREEMPT
)
1439 rq
->rq_flags
|= RQF_PREEMPT
;
1442 if (rq_flags
& RQF_ELVPRIV
) {
1443 if (unlikely(et
->icq_cache
&& !icq
)) {
1445 icq
= ioc_create_icq(ioc
, q
, gfp_mask
);
1451 if (unlikely(elv_set_request(q
, rq
, bio
, gfp_mask
)))
1454 /* @rq->elv.icq holds io_context until @rq is freed */
1456 get_io_context(icq
->ioc
);
1460 * ioc may be NULL here, and ioc_batching will be false. That's
1461 * OK, if the queue is under the request limit then requests need
1462 * not count toward the nr_batch_requests limit. There will always
1463 * be some limit enforced by BLK_BATCH_TIME.
1465 if (ioc_batching(q
, ioc
))
1466 ioc
->nr_batch_requests
--;
1468 trace_block_getrq(q
, bio
, op
);
1473 * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
1474 * and may fail indefinitely under memory pressure and thus
1475 * shouldn't stall IO. Treat this request as !elvpriv. This will
1476 * disturb iosched and blkcg but weird is bettern than dead.
1478 printk_ratelimited(KERN_WARNING
"%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
1479 __func__
, dev_name(q
->backing_dev_info
->dev
));
1481 rq
->rq_flags
&= ~RQF_ELVPRIV
;
1484 spin_lock_irq(q
->queue_lock
);
1485 q
->nr_rqs_elvpriv
--;
1486 spin_unlock_irq(q
->queue_lock
);
1491 * Allocation failed presumably due to memory. Undo anything we
1492 * might have messed up.
1494 * Allocating task should really be put onto the front of the wait
1495 * queue, but this is pretty rare.
1497 spin_lock_irq(q
->queue_lock
);
1498 freed_request(rl
, is_sync
, rq_flags
);
1501 * in the very unlikely event that allocation failed and no
1502 * requests for this direction was pending, mark us starved so that
1503 * freeing of a request in the other direction will notice
1504 * us. another possible fix would be to split the rq mempool into
1508 if (unlikely(rl
->count
[is_sync
] == 0))
1509 rl
->starved
[is_sync
] = 1;
1510 return ERR_PTR(-ENOMEM
);
1514 * get_request - get a free request
1515 * @q: request_queue to allocate request from
1516 * @op: operation and flags
1517 * @bio: bio to allocate request for (can be %NULL)
1518 * @flags: BLK_MQ_REQ_* flags.
1520 * Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,
1521 * this function keeps retrying under memory pressure and fails iff @q is dead.
1523 * Must be called with @q->queue_lock held and,
1524 * Returns ERR_PTR on failure, with @q->queue_lock held.
1525 * Returns request pointer on success, with @q->queue_lock *not held*.
1527 static struct request
*get_request(struct request_queue
*q
, unsigned int op
,
1528 struct bio
*bio
, blk_mq_req_flags_t flags
)
1530 const bool is_sync
= op_is_sync(op
);
1532 struct request_list
*rl
;
1535 lockdep_assert_held(q
->queue_lock
);
1536 WARN_ON_ONCE(q
->mq_ops
);
1538 rl
= blk_get_rl(q
, bio
); /* transferred to @rq on success */
1540 rq
= __get_request(rl
, op
, bio
, flags
);
1544 if (op
& REQ_NOWAIT
) {
1546 return ERR_PTR(-EAGAIN
);
1549 if ((flags
& BLK_MQ_REQ_NOWAIT
) || unlikely(blk_queue_dying(q
))) {
1554 /* wait on @rl and retry */
1555 prepare_to_wait_exclusive(&rl
->wait
[is_sync
], &wait
,
1556 TASK_UNINTERRUPTIBLE
);
1558 trace_block_sleeprq(q
, bio
, op
);
1560 spin_unlock_irq(q
->queue_lock
);
1564 * After sleeping, we become a "batching" process and will be able
1565 * to allocate at least one request, and up to a big batch of them
1566 * for a small period time. See ioc_batching, ioc_set_batching
1568 ioc_set_batching(q
, current
->io_context
);
1570 spin_lock_irq(q
->queue_lock
);
1571 finish_wait(&rl
->wait
[is_sync
], &wait
);
1576 /* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */
1577 static struct request
*blk_old_get_request(struct request_queue
*q
,
1578 unsigned int op
, blk_mq_req_flags_t flags
)
1581 gfp_t gfp_mask
= flags
& BLK_MQ_REQ_NOWAIT
? GFP_ATOMIC
:
1582 __GFP_DIRECT_RECLAIM
;
1585 WARN_ON_ONCE(q
->mq_ops
);
1587 /* create ioc upfront */
1588 create_io_context(gfp_mask
, q
->node
);
1590 ret
= blk_queue_enter(q
, flags
);
1592 return ERR_PTR(ret
);
1593 spin_lock_irq(q
->queue_lock
);
1594 rq
= get_request(q
, op
, NULL
, flags
);
1596 spin_unlock_irq(q
->queue_lock
);
1601 /* q->queue_lock is unlocked at this point */
1603 rq
->__sector
= (sector_t
) -1;
1604 rq
->bio
= rq
->biotail
= NULL
;
1609 * blk_get_request_flags - allocate a request
1610 * @q: request queue to allocate a request for
1611 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
1612 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
1614 struct request
*blk_get_request_flags(struct request_queue
*q
, unsigned int op
,
1615 blk_mq_req_flags_t flags
)
1617 struct request
*req
;
1619 WARN_ON_ONCE(op
& REQ_NOWAIT
);
1620 WARN_ON_ONCE(flags
& ~(BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_PREEMPT
));
1623 req
= blk_mq_alloc_request(q
, op
, flags
);
1624 if (!IS_ERR(req
) && q
->mq_ops
->initialize_rq_fn
)
1625 q
->mq_ops
->initialize_rq_fn(req
);
1627 req
= blk_old_get_request(q
, op
, flags
);
1628 if (!IS_ERR(req
) && q
->initialize_rq_fn
)
1629 q
->initialize_rq_fn(req
);
1634 EXPORT_SYMBOL(blk_get_request_flags
);
1636 struct request
*blk_get_request(struct request_queue
*q
, unsigned int op
,
1639 return blk_get_request_flags(q
, op
, gfp_mask
& __GFP_DIRECT_RECLAIM
?
1640 0 : BLK_MQ_REQ_NOWAIT
);
1642 EXPORT_SYMBOL(blk_get_request
);
1645 * blk_requeue_request - put a request back on queue
1646 * @q: request queue where request should be inserted
1647 * @rq: request to be inserted
1650 * Drivers often keep queueing requests until the hardware cannot accept
1651 * more, when that condition happens we need to put the request back
1652 * on the queue. Must be called with queue lock held.
1654 void blk_requeue_request(struct request_queue
*q
, struct request
*rq
)
1656 lockdep_assert_held(q
->queue_lock
);
1657 WARN_ON_ONCE(q
->mq_ops
);
1659 blk_delete_timer(rq
);
1660 blk_clear_rq_complete(rq
);
1661 trace_block_rq_requeue(q
, rq
);
1662 wbt_requeue(q
->rq_wb
, &rq
->issue_stat
);
1664 if (rq
->rq_flags
& RQF_QUEUED
)
1665 blk_queue_end_tag(q
, rq
);
1667 BUG_ON(blk_queued_rq(rq
));
1669 elv_requeue_request(q
, rq
);
1671 EXPORT_SYMBOL(blk_requeue_request
);
1673 static void add_acct_request(struct request_queue
*q
, struct request
*rq
,
1676 blk_account_io_start(rq
, true);
1677 __elv_add_request(q
, rq
, where
);
1680 static void part_round_stats_single(struct request_queue
*q
, int cpu
,
1681 struct hd_struct
*part
, unsigned long now
,
1682 unsigned int inflight
)
1685 __part_stat_add(cpu
, part
, time_in_queue
,
1686 inflight
* (now
- part
->stamp
));
1687 __part_stat_add(cpu
, part
, io_ticks
, (now
- part
->stamp
));
1693 * part_round_stats() - Round off the performance stats on a struct disk_stats.
1694 * @q: target block queue
1695 * @cpu: cpu number for stats access
1696 * @part: target partition
1698 * The average IO queue length and utilisation statistics are maintained
1699 * by observing the current state of the queue length and the amount of
1700 * time it has been in this state for.
1702 * Normally, that accounting is done on IO completion, but that can result
1703 * in more than a second's worth of IO being accounted for within any one
1704 * second, leading to >100% utilisation. To deal with that, we call this
1705 * function to do a round-off before returning the results when reading
1706 * /proc/diskstats. This accounts immediately for all queue usage up to
1707 * the current jiffies and restarts the counters again.
1709 void part_round_stats(struct request_queue
*q
, int cpu
, struct hd_struct
*part
)
1711 struct hd_struct
*part2
= NULL
;
1712 unsigned long now
= jiffies
;
1713 unsigned int inflight
[2];
1716 if (part
->stamp
!= now
)
1720 part2
= &part_to_disk(part
)->part0
;
1721 if (part2
->stamp
!= now
)
1728 part_in_flight(q
, part
, inflight
);
1731 part_round_stats_single(q
, cpu
, part2
, now
, inflight
[1]);
1733 part_round_stats_single(q
, cpu
, part
, now
, inflight
[0]);
1735 EXPORT_SYMBOL_GPL(part_round_stats
);
1738 static void blk_pm_put_request(struct request
*rq
)
1740 if (rq
->q
->dev
&& !(rq
->rq_flags
& RQF_PM
) && !--rq
->q
->nr_pending
)
1741 pm_runtime_mark_last_busy(rq
->q
->dev
);
1744 static inline void blk_pm_put_request(struct request
*rq
) {}
1747 void __blk_put_request(struct request_queue
*q
, struct request
*req
)
1749 req_flags_t rq_flags
= req
->rq_flags
;
1755 blk_mq_free_request(req
);
1759 lockdep_assert_held(q
->queue_lock
);
1761 blk_req_zone_write_unlock(req
);
1762 blk_pm_put_request(req
);
1764 elv_completed_request(q
, req
);
1766 /* this is a bio leak */
1767 WARN_ON(req
->bio
!= NULL
);
1769 wbt_done(q
->rq_wb
, &req
->issue_stat
);
1772 * Request may not have originated from ll_rw_blk. if not,
1773 * it didn't come out of our reserved rq pools
1775 if (rq_flags
& RQF_ALLOCED
) {
1776 struct request_list
*rl
= blk_rq_rl(req
);
1777 bool sync
= op_is_sync(req
->cmd_flags
);
1779 BUG_ON(!list_empty(&req
->queuelist
));
1780 BUG_ON(ELV_ON_HASH(req
));
1782 blk_free_request(rl
, req
);
1783 freed_request(rl
, sync
, rq_flags
);
1788 EXPORT_SYMBOL_GPL(__blk_put_request
);
1790 void blk_put_request(struct request
*req
)
1792 struct request_queue
*q
= req
->q
;
1795 blk_mq_free_request(req
);
1797 unsigned long flags
;
1799 spin_lock_irqsave(q
->queue_lock
, flags
);
1800 __blk_put_request(q
, req
);
1801 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1804 EXPORT_SYMBOL(blk_put_request
);
1806 bool bio_attempt_back_merge(struct request_queue
*q
, struct request
*req
,
1809 const int ff
= bio
->bi_opf
& REQ_FAILFAST_MASK
;
1811 if (!ll_back_merge_fn(q
, req
, bio
))
1814 trace_block_bio_backmerge(q
, req
, bio
);
1816 if ((req
->cmd_flags
& REQ_FAILFAST_MASK
) != ff
)
1817 blk_rq_set_mixed_merge(req
);
1819 req
->biotail
->bi_next
= bio
;
1821 req
->__data_len
+= bio
->bi_iter
.bi_size
;
1822 req
->ioprio
= ioprio_best(req
->ioprio
, bio_prio(bio
));
1824 blk_account_io_start(req
, false);
1828 bool bio_attempt_front_merge(struct request_queue
*q
, struct request
*req
,
1831 const int ff
= bio
->bi_opf
& REQ_FAILFAST_MASK
;
1833 if (!ll_front_merge_fn(q
, req
, bio
))
1836 trace_block_bio_frontmerge(q
, req
, bio
);
1838 if ((req
->cmd_flags
& REQ_FAILFAST_MASK
) != ff
)
1839 blk_rq_set_mixed_merge(req
);
1841 bio
->bi_next
= req
->bio
;
1844 req
->__sector
= bio
->bi_iter
.bi_sector
;
1845 req
->__data_len
+= bio
->bi_iter
.bi_size
;
1846 req
->ioprio
= ioprio_best(req
->ioprio
, bio_prio(bio
));
1848 blk_account_io_start(req
, false);
1852 bool bio_attempt_discard_merge(struct request_queue
*q
, struct request
*req
,
1855 unsigned short segments
= blk_rq_nr_discard_segments(req
);
1857 if (segments
>= queue_max_discard_segments(q
))
1859 if (blk_rq_sectors(req
) + bio_sectors(bio
) >
1860 blk_rq_get_max_sectors(req
, blk_rq_pos(req
)))
1863 req
->biotail
->bi_next
= bio
;
1865 req
->__data_len
+= bio
->bi_iter
.bi_size
;
1866 req
->ioprio
= ioprio_best(req
->ioprio
, bio_prio(bio
));
1867 req
->nr_phys_segments
= segments
+ 1;
1869 blk_account_io_start(req
, false);
1872 req_set_nomerge(q
, req
);
1877 * blk_attempt_plug_merge - try to merge with %current's plugged list
1878 * @q: request_queue new bio is being queued at
1879 * @bio: new bio being queued
1880 * @request_count: out parameter for number of traversed plugged requests
1881 * @same_queue_rq: pointer to &struct request that gets filled in when
1882 * another request associated with @q is found on the plug list
1883 * (optional, may be %NULL)
1885 * Determine whether @bio being queued on @q can be merged with a request
1886 * on %current's plugged list. Returns %true if merge was successful,
1889 * Plugging coalesces IOs from the same issuer for the same purpose without
1890 * going through @q->queue_lock. As such it's more of an issuing mechanism
1891 * than scheduling, and the request, while may have elvpriv data, is not
1892 * added on the elevator at this point. In addition, we don't have
1893 * reliable access to the elevator outside queue lock. Only check basic
1894 * merging parameters without querying the elevator.
1896 * Caller must ensure !blk_queue_nomerges(q) beforehand.
1898 bool blk_attempt_plug_merge(struct request_queue
*q
, struct bio
*bio
,
1899 unsigned int *request_count
,
1900 struct request
**same_queue_rq
)
1902 struct blk_plug
*plug
;
1904 struct list_head
*plug_list
;
1906 plug
= current
->plug
;
1912 plug_list
= &plug
->mq_list
;
1914 plug_list
= &plug
->list
;
1916 list_for_each_entry_reverse(rq
, plug_list
, queuelist
) {
1917 bool merged
= false;
1922 * Only blk-mq multiple hardware queues case checks the
1923 * rq in the same queue, there should be only one such
1927 *same_queue_rq
= rq
;
1930 if (rq
->q
!= q
|| !blk_rq_merge_ok(rq
, bio
))
1933 switch (blk_try_merge(rq
, bio
)) {
1934 case ELEVATOR_BACK_MERGE
:
1935 merged
= bio_attempt_back_merge(q
, rq
, bio
);
1937 case ELEVATOR_FRONT_MERGE
:
1938 merged
= bio_attempt_front_merge(q
, rq
, bio
);
1940 case ELEVATOR_DISCARD_MERGE
:
1941 merged
= bio_attempt_discard_merge(q
, rq
, bio
);
1954 unsigned int blk_plug_queued_count(struct request_queue
*q
)
1956 struct blk_plug
*plug
;
1958 struct list_head
*plug_list
;
1959 unsigned int ret
= 0;
1961 plug
= current
->plug
;
1966 plug_list
= &plug
->mq_list
;
1968 plug_list
= &plug
->list
;
1970 list_for_each_entry(rq
, plug_list
, queuelist
) {
1978 void blk_init_request_from_bio(struct request
*req
, struct bio
*bio
)
1980 struct io_context
*ioc
= rq_ioc(bio
);
1982 if (bio
->bi_opf
& REQ_RAHEAD
)
1983 req
->cmd_flags
|= REQ_FAILFAST_MASK
;
1985 req
->__sector
= bio
->bi_iter
.bi_sector
;
1986 if (ioprio_valid(bio_prio(bio
)))
1987 req
->ioprio
= bio_prio(bio
);
1989 req
->ioprio
= ioc
->ioprio
;
1991 req
->ioprio
= IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE
, 0);
1992 req
->write_hint
= bio
->bi_write_hint
;
1993 blk_rq_bio_prep(req
->q
, req
, bio
);
1995 EXPORT_SYMBOL_GPL(blk_init_request_from_bio
);
1997 static blk_qc_t
blk_queue_bio(struct request_queue
*q
, struct bio
*bio
)
1999 struct blk_plug
*plug
;
2000 int where
= ELEVATOR_INSERT_SORT
;
2001 struct request
*req
, *free
;
2002 unsigned int request_count
= 0;
2003 unsigned int wb_acct
;
2006 * low level driver can indicate that it wants pages above a
2007 * certain limit bounced to low memory (ie for highmem, or even
2008 * ISA dma in theory)
2010 blk_queue_bounce(q
, &bio
);
2012 blk_queue_split(q
, &bio
);
2014 if (!bio_integrity_prep(bio
))
2015 return BLK_QC_T_NONE
;
2017 if (op_is_flush(bio
->bi_opf
)) {
2018 spin_lock_irq(q
->queue_lock
);
2019 where
= ELEVATOR_INSERT_FLUSH
;
2024 * Check if we can merge with the plugged list before grabbing
2027 if (!blk_queue_nomerges(q
)) {
2028 if (blk_attempt_plug_merge(q
, bio
, &request_count
, NULL
))
2029 return BLK_QC_T_NONE
;
2031 request_count
= blk_plug_queued_count(q
);
2033 spin_lock_irq(q
->queue_lock
);
2035 switch (elv_merge(q
, &req
, bio
)) {
2036 case ELEVATOR_BACK_MERGE
:
2037 if (!bio_attempt_back_merge(q
, req
, bio
))
2039 elv_bio_merged(q
, req
, bio
);
2040 free
= attempt_back_merge(q
, req
);
2042 __blk_put_request(q
, free
);
2044 elv_merged_request(q
, req
, ELEVATOR_BACK_MERGE
);
2046 case ELEVATOR_FRONT_MERGE
:
2047 if (!bio_attempt_front_merge(q
, req
, bio
))
2049 elv_bio_merged(q
, req
, bio
);
2050 free
= attempt_front_merge(q
, req
);
2052 __blk_put_request(q
, free
);
2054 elv_merged_request(q
, req
, ELEVATOR_FRONT_MERGE
);
2061 wb_acct
= wbt_wait(q
->rq_wb
, bio
, q
->queue_lock
);
2064 * Grab a free request. This is might sleep but can not fail.
2065 * Returns with the queue unlocked.
2067 blk_queue_enter_live(q
);
2068 req
= get_request(q
, bio
->bi_opf
, bio
, 0);
2071 __wbt_done(q
->rq_wb
, wb_acct
);
2072 if (PTR_ERR(req
) == -ENOMEM
)
2073 bio
->bi_status
= BLK_STS_RESOURCE
;
2075 bio
->bi_status
= BLK_STS_IOERR
;
2080 wbt_track(&req
->issue_stat
, wb_acct
);
2083 * After dropping the lock and possibly sleeping here, our request
2084 * may now be mergeable after it had proven unmergeable (above).
2085 * We don't worry about that case for efficiency. It won't happen
2086 * often, and the elevators are able to handle it.
2088 blk_init_request_from_bio(req
, bio
);
2090 if (test_bit(QUEUE_FLAG_SAME_COMP
, &q
->queue_flags
))
2091 req
->cpu
= raw_smp_processor_id();
2093 plug
= current
->plug
;
2096 * If this is the first request added after a plug, fire
2099 * @request_count may become stale because of schedule
2100 * out, so check plug list again.
2102 if (!request_count
|| list_empty(&plug
->list
))
2103 trace_block_plug(q
);
2105 struct request
*last
= list_entry_rq(plug
->list
.prev
);
2106 if (request_count
>= BLK_MAX_REQUEST_COUNT
||
2107 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
) {
2108 blk_flush_plug_list(plug
, false);
2109 trace_block_plug(q
);
2112 list_add_tail(&req
->queuelist
, &plug
->list
);
2113 blk_account_io_start(req
, true);
2115 spin_lock_irq(q
->queue_lock
);
2116 add_acct_request(q
, req
, where
);
2119 spin_unlock_irq(q
->queue_lock
);
2122 return BLK_QC_T_NONE
;
2125 static void handle_bad_sector(struct bio
*bio
, sector_t maxsector
)
2127 char b
[BDEVNAME_SIZE
];
2129 printk(KERN_INFO
"attempt to access beyond end of device\n");
2130 printk(KERN_INFO
"%s: rw=%d, want=%Lu, limit=%Lu\n",
2131 bio_devname(bio
, b
), bio
->bi_opf
,
2132 (unsigned long long)bio_end_sector(bio
),
2133 (long long)maxsector
);
2136 #ifdef CONFIG_FAIL_MAKE_REQUEST
2138 static DECLARE_FAULT_ATTR(fail_make_request
);
2140 static int __init
setup_fail_make_request(char *str
)
2142 return setup_fault_attr(&fail_make_request
, str
);
2144 __setup("fail_make_request=", setup_fail_make_request
);
2146 static bool should_fail_request(struct hd_struct
*part
, unsigned int bytes
)
2148 return part
->make_it_fail
&& should_fail(&fail_make_request
, bytes
);
2151 static int __init
fail_make_request_debugfs(void)
2153 struct dentry
*dir
= fault_create_debugfs_attr("fail_make_request",
2154 NULL
, &fail_make_request
);
2156 return PTR_ERR_OR_ZERO(dir
);
2159 late_initcall(fail_make_request_debugfs
);
2161 #else /* CONFIG_FAIL_MAKE_REQUEST */
2163 static inline bool should_fail_request(struct hd_struct
*part
,
2169 #endif /* CONFIG_FAIL_MAKE_REQUEST */
2171 static inline bool bio_check_ro(struct bio
*bio
, struct hd_struct
*part
)
2173 if (part
->policy
&& op_is_write(bio_op(bio
))) {
2174 char b
[BDEVNAME_SIZE
];
2177 "generic_make_request: Trying to write "
2178 "to read-only block-device %s (partno %d)\n",
2179 bio_devname(bio
, b
), part
->partno
);
2186 static noinline
int should_fail_bio(struct bio
*bio
)
2188 if (should_fail_request(&bio
->bi_disk
->part0
, bio
->bi_iter
.bi_size
))
2192 ALLOW_ERROR_INJECTION(should_fail_bio
, ERRNO
);
2195 * Check whether this bio extends beyond the end of the device or partition.
2196 * This may well happen - the kernel calls bread() without checking the size of
2197 * the device, e.g., when mounting a file system.
2199 static inline int bio_check_eod(struct bio
*bio
, sector_t maxsector
)
2201 unsigned int nr_sectors
= bio_sectors(bio
);
2203 if (nr_sectors
&& maxsector
&&
2204 (nr_sectors
> maxsector
||
2205 bio
->bi_iter
.bi_sector
> maxsector
- nr_sectors
)) {
2206 handle_bad_sector(bio
, maxsector
);
2213 * Remap block n of partition p to block n+start(p) of the disk.
2215 static inline int blk_partition_remap(struct bio
*bio
)
2217 struct hd_struct
*p
;
2221 p
= __disk_get_part(bio
->bi_disk
, bio
->bi_partno
);
2224 if (unlikely(should_fail_request(p
, bio
->bi_iter
.bi_size
)))
2226 if (unlikely(bio_check_ro(bio
, p
)))
2230 * Zone reset does not include bi_size so bio_sectors() is always 0.
2231 * Include a test for the reset op code and perform the remap if needed.
2233 if (bio_sectors(bio
) || bio_op(bio
) == REQ_OP_ZONE_RESET
) {
2234 if (bio_check_eod(bio
, part_nr_sects_read(p
)))
2236 bio
->bi_iter
.bi_sector
+= p
->start_sect
;
2238 trace_block_bio_remap(bio
->bi_disk
->queue
, bio
, part_devt(p
),
2239 bio
->bi_iter
.bi_sector
- p
->start_sect
);
2247 static noinline_for_stack
bool
2248 generic_make_request_checks(struct bio
*bio
)
2250 struct request_queue
*q
;
2251 int nr_sectors
= bio_sectors(bio
);
2252 blk_status_t status
= BLK_STS_IOERR
;
2253 char b
[BDEVNAME_SIZE
];
2257 q
= bio
->bi_disk
->queue
;
2260 "generic_make_request: Trying to access "
2261 "nonexistent block-device %s (%Lu)\n",
2262 bio_devname(bio
, b
), (long long)bio
->bi_iter
.bi_sector
);
2267 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
2268 * if queue is not a request based queue.
2270 if ((bio
->bi_opf
& REQ_NOWAIT
) && !queue_is_rq_based(q
))
2273 if (should_fail_bio(bio
))
2276 if (bio
->bi_partno
) {
2277 if (unlikely(blk_partition_remap(bio
)))
2280 if (unlikely(bio_check_ro(bio
, &bio
->bi_disk
->part0
)))
2282 if (unlikely(bio_check_eod(bio
, get_capacity(bio
->bi_disk
))))
2287 * Filter flush bio's early so that make_request based
2288 * drivers without flush support don't have to worry
2291 if (op_is_flush(bio
->bi_opf
) &&
2292 !test_bit(QUEUE_FLAG_WC
, &q
->queue_flags
)) {
2293 bio
->bi_opf
&= ~(REQ_PREFLUSH
| REQ_FUA
);
2295 status
= BLK_STS_OK
;
2300 switch (bio_op(bio
)) {
2301 case REQ_OP_DISCARD
:
2302 if (!blk_queue_discard(q
))
2305 case REQ_OP_SECURE_ERASE
:
2306 if (!blk_queue_secure_erase(q
))
2309 case REQ_OP_WRITE_SAME
:
2310 if (!q
->limits
.max_write_same_sectors
)
2313 case REQ_OP_ZONE_REPORT
:
2314 case REQ_OP_ZONE_RESET
:
2315 if (!blk_queue_is_zoned(q
))
2318 case REQ_OP_WRITE_ZEROES
:
2319 if (!q
->limits
.max_write_zeroes_sectors
)
2327 * Various block parts want %current->io_context and lazy ioc
2328 * allocation ends up trading a lot of pain for a small amount of
2329 * memory. Just allocate it upfront. This may fail and block
2330 * layer knows how to live with it.
2332 create_io_context(GFP_ATOMIC
, q
->node
);
2334 if (!blkcg_bio_issue_check(q
, bio
))
2337 if (!bio_flagged(bio
, BIO_TRACE_COMPLETION
)) {
2338 trace_block_bio_queue(q
, bio
);
2339 /* Now that enqueuing has been traced, we need to trace
2340 * completion as well.
2342 bio_set_flag(bio
, BIO_TRACE_COMPLETION
);
2347 status
= BLK_STS_NOTSUPP
;
2349 bio
->bi_status
= status
;
2355 * generic_make_request - hand a buffer to its device driver for I/O
2356 * @bio: The bio describing the location in memory and on the device.
2358 * generic_make_request() is used to make I/O requests of block
2359 * devices. It is passed a &struct bio, which describes the I/O that needs
2362 * generic_make_request() does not return any status. The
2363 * success/failure status of the request, along with notification of
2364 * completion, is delivered asynchronously through the bio->bi_end_io
2365 * function described (one day) else where.
2367 * The caller of generic_make_request must make sure that bi_io_vec
2368 * are set to describe the memory buffer, and that bi_dev and bi_sector are
2369 * set to describe the device address, and the
2370 * bi_end_io and optionally bi_private are set to describe how
2371 * completion notification should be signaled.
2373 * generic_make_request and the drivers it calls may use bi_next if this
2374 * bio happens to be merged with someone else, and may resubmit the bio to
2375 * a lower device by calling into generic_make_request recursively, which
2376 * means the bio should NOT be touched after the call to ->make_request_fn.
2378 blk_qc_t
generic_make_request(struct bio
*bio
)
2381 * bio_list_on_stack[0] contains bios submitted by the current
2383 * bio_list_on_stack[1] contains bios that were submitted before
2384 * the current make_request_fn, but that haven't been processed
2387 struct bio_list bio_list_on_stack
[2];
2388 blk_qc_t ret
= BLK_QC_T_NONE
;
2390 if (!generic_make_request_checks(bio
))
2394 * We only want one ->make_request_fn to be active at a time, else
2395 * stack usage with stacked devices could be a problem. So use
2396 * current->bio_list to keep a list of requests submited by a
2397 * make_request_fn function. current->bio_list is also used as a
2398 * flag to say if generic_make_request is currently active in this
2399 * task or not. If it is NULL, then no make_request is active. If
2400 * it is non-NULL, then a make_request is active, and new requests
2401 * should be added at the tail
2403 if (current
->bio_list
) {
2404 bio_list_add(¤t
->bio_list
[0], bio
);
2408 /* following loop may be a bit non-obvious, and so deserves some
2410 * Before entering the loop, bio->bi_next is NULL (as all callers
2411 * ensure that) so we have a list with a single bio.
2412 * We pretend that we have just taken it off a longer list, so
2413 * we assign bio_list to a pointer to the bio_list_on_stack,
2414 * thus initialising the bio_list of new bios to be
2415 * added. ->make_request() may indeed add some more bios
2416 * through a recursive call to generic_make_request. If it
2417 * did, we find a non-NULL value in bio_list and re-enter the loop
2418 * from the top. In this case we really did just take the bio
2419 * of the top of the list (no pretending) and so remove it from
2420 * bio_list, and call into ->make_request() again.
2422 BUG_ON(bio
->bi_next
);
2423 bio_list_init(&bio_list_on_stack
[0]);
2424 current
->bio_list
= bio_list_on_stack
;
2426 struct request_queue
*q
= bio
->bi_disk
->queue
;
2427 blk_mq_req_flags_t flags
= bio
->bi_opf
& REQ_NOWAIT
?
2428 BLK_MQ_REQ_NOWAIT
: 0;
2430 if (likely(blk_queue_enter(q
, flags
) == 0)) {
2431 struct bio_list lower
, same
;
2433 /* Create a fresh bio_list for all subordinate requests */
2434 bio_list_on_stack
[1] = bio_list_on_stack
[0];
2435 bio_list_init(&bio_list_on_stack
[0]);
2436 ret
= q
->make_request_fn(q
, bio
);
2440 /* sort new bios into those for a lower level
2441 * and those for the same level
2443 bio_list_init(&lower
);
2444 bio_list_init(&same
);
2445 while ((bio
= bio_list_pop(&bio_list_on_stack
[0])) != NULL
)
2446 if (q
== bio
->bi_disk
->queue
)
2447 bio_list_add(&same
, bio
);
2449 bio_list_add(&lower
, bio
);
2450 /* now assemble so we handle the lowest level first */
2451 bio_list_merge(&bio_list_on_stack
[0], &lower
);
2452 bio_list_merge(&bio_list_on_stack
[0], &same
);
2453 bio_list_merge(&bio_list_on_stack
[0], &bio_list_on_stack
[1]);
2455 if (unlikely(!blk_queue_dying(q
) &&
2456 (bio
->bi_opf
& REQ_NOWAIT
)))
2457 bio_wouldblock_error(bio
);
2461 bio
= bio_list_pop(&bio_list_on_stack
[0]);
2463 current
->bio_list
= NULL
; /* deactivate */
2468 EXPORT_SYMBOL(generic_make_request
);
2471 * direct_make_request - hand a buffer directly to its device driver for I/O
2472 * @bio: The bio describing the location in memory and on the device.
2474 * This function behaves like generic_make_request(), but does not protect
2475 * against recursion. Must only be used if the called driver is known
2476 * to not call generic_make_request (or direct_make_request) again from
2477 * its make_request function. (Calling direct_make_request again from
2478 * a workqueue is perfectly fine as that doesn't recurse).
2480 blk_qc_t
direct_make_request(struct bio
*bio
)
2482 struct request_queue
*q
= bio
->bi_disk
->queue
;
2483 bool nowait
= bio
->bi_opf
& REQ_NOWAIT
;
2486 if (!generic_make_request_checks(bio
))
2487 return BLK_QC_T_NONE
;
2489 if (unlikely(blk_queue_enter(q
, nowait
? BLK_MQ_REQ_NOWAIT
: 0))) {
2490 if (nowait
&& !blk_queue_dying(q
))
2491 bio
->bi_status
= BLK_STS_AGAIN
;
2493 bio
->bi_status
= BLK_STS_IOERR
;
2495 return BLK_QC_T_NONE
;
2498 ret
= q
->make_request_fn(q
, bio
);
2502 EXPORT_SYMBOL_GPL(direct_make_request
);
2505 * submit_bio - submit a bio to the block device layer for I/O
2506 * @bio: The &struct bio which describes the I/O
2508 * submit_bio() is very similar in purpose to generic_make_request(), and
2509 * uses that function to do most of the work. Both are fairly rough
2510 * interfaces; @bio must be presetup and ready for I/O.
2513 blk_qc_t
submit_bio(struct bio
*bio
)
2516 * If it's a regular read/write or a barrier with data attached,
2517 * go through the normal accounting stuff before submission.
2519 if (bio_has_data(bio
)) {
2522 if (unlikely(bio_op(bio
) == REQ_OP_WRITE_SAME
))
2523 count
= queue_logical_block_size(bio
->bi_disk
->queue
) >> 9;
2525 count
= bio_sectors(bio
);
2527 if (op_is_write(bio_op(bio
))) {
2528 count_vm_events(PGPGOUT
, count
);
2530 task_io_account_read(bio
->bi_iter
.bi_size
);
2531 count_vm_events(PGPGIN
, count
);
2534 if (unlikely(block_dump
)) {
2535 char b
[BDEVNAME_SIZE
];
2536 printk(KERN_DEBUG
"%s(%d): %s block %Lu on %s (%u sectors)\n",
2537 current
->comm
, task_pid_nr(current
),
2538 op_is_write(bio_op(bio
)) ? "WRITE" : "READ",
2539 (unsigned long long)bio
->bi_iter
.bi_sector
,
2540 bio_devname(bio
, b
), count
);
2544 return generic_make_request(bio
);
2546 EXPORT_SYMBOL(submit_bio
);
2548 bool blk_poll(struct request_queue
*q
, blk_qc_t cookie
)
2550 if (!q
->poll_fn
|| !blk_qc_t_valid(cookie
))
2554 blk_flush_plug_list(current
->plug
, false);
2555 return q
->poll_fn(q
, cookie
);
2557 EXPORT_SYMBOL_GPL(blk_poll
);
2560 * blk_cloned_rq_check_limits - Helper function to check a cloned request
2561 * for new the queue limits
2563 * @rq: the request being checked
2566 * @rq may have been made based on weaker limitations of upper-level queues
2567 * in request stacking drivers, and it may violate the limitation of @q.
2568 * Since the block layer and the underlying device driver trust @rq
2569 * after it is inserted to @q, it should be checked against @q before
2570 * the insertion using this generic function.
2572 * Request stacking drivers like request-based dm may change the queue
2573 * limits when retrying requests on other queues. Those requests need
2574 * to be checked against the new queue limits again during dispatch.
2576 static int blk_cloned_rq_check_limits(struct request_queue
*q
,
2579 if (blk_rq_sectors(rq
) > blk_queue_get_max_sectors(q
, req_op(rq
))) {
2580 printk(KERN_ERR
"%s: over max size limit.\n", __func__
);
2585 * queue's settings related to segment counting like q->bounce_pfn
2586 * may differ from that of other stacking queues.
2587 * Recalculate it to check the request correctly on this queue's
2590 blk_recalc_rq_segments(rq
);
2591 if (rq
->nr_phys_segments
> queue_max_segments(q
)) {
2592 printk(KERN_ERR
"%s: over max segments limit.\n", __func__
);
2600 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2601 * @q: the queue to submit the request
2602 * @rq: the request being queued
2604 blk_status_t
blk_insert_cloned_request(struct request_queue
*q
, struct request
*rq
)
2606 unsigned long flags
;
2607 int where
= ELEVATOR_INSERT_BACK
;
2609 if (blk_cloned_rq_check_limits(q
, rq
))
2610 return BLK_STS_IOERR
;
2613 should_fail_request(&rq
->rq_disk
->part0
, blk_rq_bytes(rq
)))
2614 return BLK_STS_IOERR
;
2617 if (blk_queue_io_stat(q
))
2618 blk_account_io_start(rq
, true);
2620 * Since we have a scheduler attached on the top device,
2621 * bypass a potential scheduler on the bottom device for
2624 return blk_mq_request_issue_directly(rq
);
2627 spin_lock_irqsave(q
->queue_lock
, flags
);
2628 if (unlikely(blk_queue_dying(q
))) {
2629 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2630 return BLK_STS_IOERR
;
2634 * Submitting request must be dequeued before calling this function
2635 * because it will be linked to another request_queue
2637 BUG_ON(blk_queued_rq(rq
));
2639 if (op_is_flush(rq
->cmd_flags
))
2640 where
= ELEVATOR_INSERT_FLUSH
;
2642 add_acct_request(q
, rq
, where
);
2643 if (where
== ELEVATOR_INSERT_FLUSH
)
2645 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2649 EXPORT_SYMBOL_GPL(blk_insert_cloned_request
);
2652 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
2653 * @rq: request to examine
2656 * A request could be merge of IOs which require different failure
2657 * handling. This function determines the number of bytes which
2658 * can be failed from the beginning of the request without
2659 * crossing into area which need to be retried further.
2662 * The number of bytes to fail.
2664 unsigned int blk_rq_err_bytes(const struct request
*rq
)
2666 unsigned int ff
= rq
->cmd_flags
& REQ_FAILFAST_MASK
;
2667 unsigned int bytes
= 0;
2670 if (!(rq
->rq_flags
& RQF_MIXED_MERGE
))
2671 return blk_rq_bytes(rq
);
2674 * Currently the only 'mixing' which can happen is between
2675 * different fastfail types. We can safely fail portions
2676 * which have all the failfast bits that the first one has -
2677 * the ones which are at least as eager to fail as the first
2680 for (bio
= rq
->bio
; bio
; bio
= bio
->bi_next
) {
2681 if ((bio
->bi_opf
& ff
) != ff
)
2683 bytes
+= bio
->bi_iter
.bi_size
;
2686 /* this could lead to infinite loop */
2687 BUG_ON(blk_rq_bytes(rq
) && !bytes
);
2690 EXPORT_SYMBOL_GPL(blk_rq_err_bytes
);
2692 void blk_account_io_completion(struct request
*req
, unsigned int bytes
)
2694 if (blk_do_io_stat(req
)) {
2695 const int rw
= rq_data_dir(req
);
2696 struct hd_struct
*part
;
2699 cpu
= part_stat_lock();
2701 part_stat_add(cpu
, part
, sectors
[rw
], bytes
>> 9);
2706 void blk_account_io_done(struct request
*req
)
2709 * Account IO completion. flush_rq isn't accounted as a
2710 * normal IO on queueing nor completion. Accounting the
2711 * containing request is enough.
2713 if (blk_do_io_stat(req
) && !(req
->rq_flags
& RQF_FLUSH_SEQ
)) {
2714 unsigned long duration
= jiffies
- req
->start_time
;
2715 const int rw
= rq_data_dir(req
);
2716 struct hd_struct
*part
;
2719 cpu
= part_stat_lock();
2722 part_stat_inc(cpu
, part
, ios
[rw
]);
2723 part_stat_add(cpu
, part
, ticks
[rw
], duration
);
2724 part_round_stats(req
->q
, cpu
, part
);
2725 part_dec_in_flight(req
->q
, part
, rw
);
2727 hd_struct_put(part
);
2734 * Don't process normal requests when queue is suspended
2735 * or in the process of suspending/resuming
2737 static bool blk_pm_allow_request(struct request
*rq
)
2739 switch (rq
->q
->rpm_status
) {
2741 case RPM_SUSPENDING
:
2742 return rq
->rq_flags
& RQF_PM
;
2750 static bool blk_pm_allow_request(struct request
*rq
)
2756 void blk_account_io_start(struct request
*rq
, bool new_io
)
2758 struct hd_struct
*part
;
2759 int rw
= rq_data_dir(rq
);
2762 if (!blk_do_io_stat(rq
))
2765 cpu
= part_stat_lock();
2769 part_stat_inc(cpu
, part
, merges
[rw
]);
2771 part
= disk_map_sector_rcu(rq
->rq_disk
, blk_rq_pos(rq
));
2772 if (!hd_struct_try_get(part
)) {
2774 * The partition is already being removed,
2775 * the request will be accounted on the disk only
2777 * We take a reference on disk->part0 although that
2778 * partition will never be deleted, so we can treat
2779 * it as any other partition.
2781 part
= &rq
->rq_disk
->part0
;
2782 hd_struct_get(part
);
2784 part_round_stats(rq
->q
, cpu
, part
);
2785 part_inc_in_flight(rq
->q
, part
, rw
);
2792 static struct request
*elv_next_request(struct request_queue
*q
)
2795 struct blk_flush_queue
*fq
= blk_get_flush_queue(q
, NULL
);
2797 WARN_ON_ONCE(q
->mq_ops
);
2800 list_for_each_entry(rq
, &q
->queue_head
, queuelist
) {
2801 if (blk_pm_allow_request(rq
))
2804 if (rq
->rq_flags
& RQF_SOFTBARRIER
)
2809 * Flush request is running and flush request isn't queueable
2810 * in the drive, we can hold the queue till flush request is
2811 * finished. Even we don't do this, driver can't dispatch next
2812 * requests and will requeue them. And this can improve
2813 * throughput too. For example, we have request flush1, write1,
2814 * flush 2. flush1 is dispatched, then queue is hold, write1
2815 * isn't inserted to queue. After flush1 is finished, flush2
2816 * will be dispatched. Since disk cache is already clean,
2817 * flush2 will be finished very soon, so looks like flush2 is
2819 * Since the queue is hold, a flag is set to indicate the queue
2820 * should be restarted later. Please see flush_end_io() for
2823 if (fq
->flush_pending_idx
!= fq
->flush_running_idx
&&
2824 !queue_flush_queueable(q
)) {
2825 fq
->flush_queue_delayed
= 1;
2828 if (unlikely(blk_queue_bypass(q
)) ||
2829 !q
->elevator
->type
->ops
.sq
.elevator_dispatch_fn(q
, 0))
2835 * blk_peek_request - peek at the top of a request queue
2836 * @q: request queue to peek at
2839 * Return the request at the top of @q. The returned request
2840 * should be started using blk_start_request() before LLD starts
2844 * Pointer to the request at the top of @q if available. Null
2847 struct request
*blk_peek_request(struct request_queue
*q
)
2852 lockdep_assert_held(q
->queue_lock
);
2853 WARN_ON_ONCE(q
->mq_ops
);
2855 while ((rq
= elv_next_request(q
)) != NULL
) {
2856 if (!(rq
->rq_flags
& RQF_STARTED
)) {
2858 * This is the first time the device driver
2859 * sees this request (possibly after
2860 * requeueing). Notify IO scheduler.
2862 if (rq
->rq_flags
& RQF_SORTED
)
2863 elv_activate_rq(q
, rq
);
2866 * just mark as started even if we don't start
2867 * it, a request that has been delayed should
2868 * not be passed by new incoming requests
2870 rq
->rq_flags
|= RQF_STARTED
;
2871 trace_block_rq_issue(q
, rq
);
2874 if (!q
->boundary_rq
|| q
->boundary_rq
== rq
) {
2875 q
->end_sector
= rq_end_sector(rq
);
2876 q
->boundary_rq
= NULL
;
2879 if (rq
->rq_flags
& RQF_DONTPREP
)
2882 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
2884 * make sure space for the drain appears we
2885 * know we can do this because max_hw_segments
2886 * has been adjusted to be one fewer than the
2889 rq
->nr_phys_segments
++;
2895 ret
= q
->prep_rq_fn(q
, rq
);
2896 if (ret
== BLKPREP_OK
) {
2898 } else if (ret
== BLKPREP_DEFER
) {
2900 * the request may have been (partially) prepped.
2901 * we need to keep this request in the front to
2902 * avoid resource deadlock. RQF_STARTED will
2903 * prevent other fs requests from passing this one.
2905 if (q
->dma_drain_size
&& blk_rq_bytes(rq
) &&
2906 !(rq
->rq_flags
& RQF_DONTPREP
)) {
2908 * remove the space for the drain we added
2909 * so that we don't add it again
2911 --rq
->nr_phys_segments
;
2916 } else if (ret
== BLKPREP_KILL
|| ret
== BLKPREP_INVALID
) {
2917 rq
->rq_flags
|= RQF_QUIET
;
2919 * Mark this request as started so we don't trigger
2920 * any debug logic in the end I/O path.
2922 blk_start_request(rq
);
2923 __blk_end_request_all(rq
, ret
== BLKPREP_INVALID
?
2924 BLK_STS_TARGET
: BLK_STS_IOERR
);
2926 printk(KERN_ERR
"%s: bad return=%d\n", __func__
, ret
);
2933 EXPORT_SYMBOL(blk_peek_request
);
2935 static void blk_dequeue_request(struct request
*rq
)
2937 struct request_queue
*q
= rq
->q
;
2939 BUG_ON(list_empty(&rq
->queuelist
));
2940 BUG_ON(ELV_ON_HASH(rq
));
2942 list_del_init(&rq
->queuelist
);
2945 * the time frame between a request being removed from the lists
2946 * and to it is freed is accounted as io that is in progress at
2949 if (blk_account_rq(rq
)) {
2950 q
->in_flight
[rq_is_sync(rq
)]++;
2951 set_io_start_time_ns(rq
);
2956 * blk_start_request - start request processing on the driver
2957 * @req: request to dequeue
2960 * Dequeue @req and start timeout timer on it. This hands off the
2961 * request to the driver.
2963 void blk_start_request(struct request
*req
)
2965 lockdep_assert_held(req
->q
->queue_lock
);
2966 WARN_ON_ONCE(req
->q
->mq_ops
);
2968 blk_dequeue_request(req
);
2970 if (test_bit(QUEUE_FLAG_STATS
, &req
->q
->queue_flags
)) {
2971 blk_stat_set_issue(&req
->issue_stat
, blk_rq_sectors(req
));
2972 req
->rq_flags
|= RQF_STATS
;
2973 wbt_issue(req
->q
->rq_wb
, &req
->issue_stat
);
2976 BUG_ON(blk_rq_is_complete(req
));
2979 EXPORT_SYMBOL(blk_start_request
);
2982 * blk_fetch_request - fetch a request from a request queue
2983 * @q: request queue to fetch a request from
2986 * Return the request at the top of @q. The request is started on
2987 * return and LLD can start processing it immediately.
2990 * Pointer to the request at the top of @q if available. Null
2993 struct request
*blk_fetch_request(struct request_queue
*q
)
2997 lockdep_assert_held(q
->queue_lock
);
2998 WARN_ON_ONCE(q
->mq_ops
);
3000 rq
= blk_peek_request(q
);
3002 blk_start_request(rq
);
3005 EXPORT_SYMBOL(blk_fetch_request
);
3008 * Steal bios from a request and add them to a bio list.
3009 * The request must not have been partially completed before.
3011 void blk_steal_bios(struct bio_list
*list
, struct request
*rq
)
3015 list
->tail
->bi_next
= rq
->bio
;
3017 list
->head
= rq
->bio
;
3018 list
->tail
= rq
->biotail
;
3026 EXPORT_SYMBOL_GPL(blk_steal_bios
);
3029 * blk_update_request - Special helper function for request stacking drivers
3030 * @req: the request being processed
3031 * @error: block status code
3032 * @nr_bytes: number of bytes to complete @req
3035 * Ends I/O on a number of bytes attached to @req, but doesn't complete
3036 * the request structure even if @req doesn't have leftover.
3037 * If @req has leftover, sets it up for the next range of segments.
3039 * This special helper function is only for request stacking drivers
3040 * (e.g. request-based dm) so that they can handle partial completion.
3041 * Actual device drivers should use blk_end_request instead.
3043 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
3044 * %false return from this function.
3047 * %false - this request doesn't have any more data
3048 * %true - this request has more data
3050 bool blk_update_request(struct request
*req
, blk_status_t error
,
3051 unsigned int nr_bytes
)
3055 trace_block_rq_complete(req
, blk_status_to_errno(error
), nr_bytes
);
3060 if (unlikely(error
&& !blk_rq_is_passthrough(req
) &&
3061 !(req
->rq_flags
& RQF_QUIET
)))
3062 print_req_error(req
, error
);
3064 blk_account_io_completion(req
, nr_bytes
);
3068 struct bio
*bio
= req
->bio
;
3069 unsigned bio_bytes
= min(bio
->bi_iter
.bi_size
, nr_bytes
);
3071 if (bio_bytes
== bio
->bi_iter
.bi_size
)
3072 req
->bio
= bio
->bi_next
;
3074 /* Completion has already been traced */
3075 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
3076 req_bio_endio(req
, bio
, bio_bytes
, error
);
3078 total_bytes
+= bio_bytes
;
3079 nr_bytes
-= bio_bytes
;
3090 * Reset counters so that the request stacking driver
3091 * can find how many bytes remain in the request
3094 req
->__data_len
= 0;
3098 req
->__data_len
-= total_bytes
;
3100 /* update sector only for requests with clear definition of sector */
3101 if (!blk_rq_is_passthrough(req
))
3102 req
->__sector
+= total_bytes
>> 9;
3104 /* mixed attributes always follow the first bio */
3105 if (req
->rq_flags
& RQF_MIXED_MERGE
) {
3106 req
->cmd_flags
&= ~REQ_FAILFAST_MASK
;
3107 req
->cmd_flags
|= req
->bio
->bi_opf
& REQ_FAILFAST_MASK
;
3110 if (!(req
->rq_flags
& RQF_SPECIAL_PAYLOAD
)) {
3112 * If total number of sectors is less than the first segment
3113 * size, something has gone terribly wrong.
3115 if (blk_rq_bytes(req
) < blk_rq_cur_bytes(req
)) {
3116 blk_dump_rq_flags(req
, "request botched");
3117 req
->__data_len
= blk_rq_cur_bytes(req
);
3120 /* recalculate the number of segments */
3121 blk_recalc_rq_segments(req
);
3126 EXPORT_SYMBOL_GPL(blk_update_request
);
3128 static bool blk_update_bidi_request(struct request
*rq
, blk_status_t error
,
3129 unsigned int nr_bytes
,
3130 unsigned int bidi_bytes
)
3132 if (blk_update_request(rq
, error
, nr_bytes
))
3135 /* Bidi request must be completed as a whole */
3136 if (unlikely(blk_bidi_rq(rq
)) &&
3137 blk_update_request(rq
->next_rq
, error
, bidi_bytes
))
3140 if (blk_queue_add_random(rq
->q
))
3141 add_disk_randomness(rq
->rq_disk
);
3147 * blk_unprep_request - unprepare a request
3150 * This function makes a request ready for complete resubmission (or
3151 * completion). It happens only after all error handling is complete,
3152 * so represents the appropriate moment to deallocate any resources
3153 * that were allocated to the request in the prep_rq_fn. The queue
3154 * lock is held when calling this.
3156 void blk_unprep_request(struct request
*req
)
3158 struct request_queue
*q
= req
->q
;
3160 req
->rq_flags
&= ~RQF_DONTPREP
;
3161 if (q
->unprep_rq_fn
)
3162 q
->unprep_rq_fn(q
, req
);
3164 EXPORT_SYMBOL_GPL(blk_unprep_request
);
3166 void blk_finish_request(struct request
*req
, blk_status_t error
)
3168 struct request_queue
*q
= req
->q
;
3170 lockdep_assert_held(req
->q
->queue_lock
);
3171 WARN_ON_ONCE(q
->mq_ops
);
3173 if (req
->rq_flags
& RQF_STATS
)
3176 if (req
->rq_flags
& RQF_QUEUED
)
3177 blk_queue_end_tag(q
, req
);
3179 BUG_ON(blk_queued_rq(req
));
3181 if (unlikely(laptop_mode
) && !blk_rq_is_passthrough(req
))
3182 laptop_io_completion(req
->q
->backing_dev_info
);
3184 blk_delete_timer(req
);
3186 if (req
->rq_flags
& RQF_DONTPREP
)
3187 blk_unprep_request(req
);
3189 blk_account_io_done(req
);
3192 wbt_done(req
->q
->rq_wb
, &req
->issue_stat
);
3193 req
->end_io(req
, error
);
3195 if (blk_bidi_rq(req
))
3196 __blk_put_request(req
->next_rq
->q
, req
->next_rq
);
3198 __blk_put_request(q
, req
);
3201 EXPORT_SYMBOL(blk_finish_request
);
3204 * blk_end_bidi_request - Complete a bidi request
3205 * @rq: the request to complete
3206 * @error: block status code
3207 * @nr_bytes: number of bytes to complete @rq
3208 * @bidi_bytes: number of bytes to complete @rq->next_rq
3211 * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
3212 * Drivers that supports bidi can safely call this member for any
3213 * type of request, bidi or uni. In the later case @bidi_bytes is
3217 * %false - we are done with this request
3218 * %true - still buffers pending for this request
3220 static bool blk_end_bidi_request(struct request
*rq
, blk_status_t error
,
3221 unsigned int nr_bytes
, unsigned int bidi_bytes
)
3223 struct request_queue
*q
= rq
->q
;
3224 unsigned long flags
;
3226 WARN_ON_ONCE(q
->mq_ops
);
3228 if (blk_update_bidi_request(rq
, error
, nr_bytes
, bidi_bytes
))
3231 spin_lock_irqsave(q
->queue_lock
, flags
);
3232 blk_finish_request(rq
, error
);
3233 spin_unlock_irqrestore(q
->queue_lock
, flags
);
3239 * __blk_end_bidi_request - Complete a bidi request with queue lock held
3240 * @rq: the request to complete
3241 * @error: block status code
3242 * @nr_bytes: number of bytes to complete @rq
3243 * @bidi_bytes: number of bytes to complete @rq->next_rq
3246 * Identical to blk_end_bidi_request() except that queue lock is
3247 * assumed to be locked on entry and remains so on return.
3250 * %false - we are done with this request
3251 * %true - still buffers pending for this request
3253 static bool __blk_end_bidi_request(struct request
*rq
, blk_status_t error
,
3254 unsigned int nr_bytes
, unsigned int bidi_bytes
)
3256 lockdep_assert_held(rq
->q
->queue_lock
);
3257 WARN_ON_ONCE(rq
->q
->mq_ops
);
3259 if (blk_update_bidi_request(rq
, error
, nr_bytes
, bidi_bytes
))
3262 blk_finish_request(rq
, error
);
3268 * blk_end_request - Helper function for drivers to complete the request.
3269 * @rq: the request being processed
3270 * @error: block status code
3271 * @nr_bytes: number of bytes to complete
3274 * Ends I/O on a number of bytes attached to @rq.
3275 * If @rq has leftover, sets it up for the next range of segments.
3278 * %false - we are done with this request
3279 * %true - still buffers pending for this request
3281 bool blk_end_request(struct request
*rq
, blk_status_t error
,
3282 unsigned int nr_bytes
)
3284 WARN_ON_ONCE(rq
->q
->mq_ops
);
3285 return blk_end_bidi_request(rq
, error
, nr_bytes
, 0);
3287 EXPORT_SYMBOL(blk_end_request
);
3290 * blk_end_request_all - Helper function for drives to finish the request.
3291 * @rq: the request to finish
3292 * @error: block status code
3295 * Completely finish @rq.
3297 void blk_end_request_all(struct request
*rq
, blk_status_t error
)
3300 unsigned int bidi_bytes
= 0;
3302 if (unlikely(blk_bidi_rq(rq
)))
3303 bidi_bytes
= blk_rq_bytes(rq
->next_rq
);
3305 pending
= blk_end_bidi_request(rq
, error
, blk_rq_bytes(rq
), bidi_bytes
);
3308 EXPORT_SYMBOL(blk_end_request_all
);
3311 * __blk_end_request - Helper function for drivers to complete the request.
3312 * @rq: the request being processed
3313 * @error: block status code
3314 * @nr_bytes: number of bytes to complete
3317 * Must be called with queue lock held unlike blk_end_request().
3320 * %false - we are done with this request
3321 * %true - still buffers pending for this request
3323 bool __blk_end_request(struct request
*rq
, blk_status_t error
,
3324 unsigned int nr_bytes
)
3326 lockdep_assert_held(rq
->q
->queue_lock
);
3327 WARN_ON_ONCE(rq
->q
->mq_ops
);
3329 return __blk_end_bidi_request(rq
, error
, nr_bytes
, 0);
3331 EXPORT_SYMBOL(__blk_end_request
);
3334 * __blk_end_request_all - Helper function for drives to finish the request.
3335 * @rq: the request to finish
3336 * @error: block status code
3339 * Completely finish @rq. Must be called with queue lock held.
3341 void __blk_end_request_all(struct request
*rq
, blk_status_t error
)
3344 unsigned int bidi_bytes
= 0;
3346 lockdep_assert_held(rq
->q
->queue_lock
);
3347 WARN_ON_ONCE(rq
->q
->mq_ops
);
3349 if (unlikely(blk_bidi_rq(rq
)))
3350 bidi_bytes
= blk_rq_bytes(rq
->next_rq
);
3352 pending
= __blk_end_bidi_request(rq
, error
, blk_rq_bytes(rq
), bidi_bytes
);
3355 EXPORT_SYMBOL(__blk_end_request_all
);
3358 * __blk_end_request_cur - Helper function to finish the current request chunk.
3359 * @rq: the request to finish the current chunk for
3360 * @error: block status code
3363 * Complete the current consecutively mapped chunk from @rq. Must
3364 * be called with queue lock held.
3367 * %false - we are done with this request
3368 * %true - still buffers pending for this request
3370 bool __blk_end_request_cur(struct request
*rq
, blk_status_t error
)
3372 return __blk_end_request(rq
, error
, blk_rq_cur_bytes(rq
));
3374 EXPORT_SYMBOL(__blk_end_request_cur
);
3376 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
3379 if (bio_has_data(bio
))
3380 rq
->nr_phys_segments
= bio_phys_segments(q
, bio
);
3381 else if (bio_op(bio
) == REQ_OP_DISCARD
)
3382 rq
->nr_phys_segments
= 1;
3384 rq
->__data_len
= bio
->bi_iter
.bi_size
;
3385 rq
->bio
= rq
->biotail
= bio
;
3388 rq
->rq_disk
= bio
->bi_disk
;
3391 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
3393 * rq_flush_dcache_pages - Helper function to flush all pages in a request
3394 * @rq: the request to be flushed
3397 * Flush all pages in @rq.
3399 void rq_flush_dcache_pages(struct request
*rq
)
3401 struct req_iterator iter
;
3402 struct bio_vec bvec
;
3404 rq_for_each_segment(bvec
, rq
, iter
)
3405 flush_dcache_page(bvec
.bv_page
);
3407 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages
);
3411 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
3412 * @q : the queue of the device being checked
3415 * Check if underlying low-level drivers of a device are busy.
3416 * If the drivers want to export their busy state, they must set own
3417 * exporting function using blk_queue_lld_busy() first.
3419 * Basically, this function is used only by request stacking drivers
3420 * to stop dispatching requests to underlying devices when underlying
3421 * devices are busy. This behavior helps more I/O merging on the queue
3422 * of the request stacking driver and prevents I/O throughput regression
3423 * on burst I/O load.
3426 * 0 - Not busy (The request stacking driver should dispatch request)
3427 * 1 - Busy (The request stacking driver should stop dispatching request)
3429 int blk_lld_busy(struct request_queue
*q
)
3432 return q
->lld_busy_fn(q
);
3436 EXPORT_SYMBOL_GPL(blk_lld_busy
);
3439 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3440 * @rq: the clone request to be cleaned up
3443 * Free all bios in @rq for a cloned request.
3445 void blk_rq_unprep_clone(struct request
*rq
)
3449 while ((bio
= rq
->bio
) != NULL
) {
3450 rq
->bio
= bio
->bi_next
;
3455 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone
);
3458 * Copy attributes of the original request to the clone request.
3459 * The actual data parts (e.g. ->cmd, ->sense) are not copied.
3461 static void __blk_rq_prep_clone(struct request
*dst
, struct request
*src
)
3463 dst
->cpu
= src
->cpu
;
3464 dst
->__sector
= blk_rq_pos(src
);
3465 dst
->__data_len
= blk_rq_bytes(src
);
3466 dst
->nr_phys_segments
= src
->nr_phys_segments
;
3467 dst
->ioprio
= src
->ioprio
;
3468 dst
->extra_len
= src
->extra_len
;
3472 * blk_rq_prep_clone - Helper function to setup clone request
3473 * @rq: the request to be setup
3474 * @rq_src: original request to be cloned
3475 * @bs: bio_set that bios for clone are allocated from
3476 * @gfp_mask: memory allocation mask for bio
3477 * @bio_ctr: setup function to be called for each clone bio.
3478 * Returns %0 for success, non %0 for failure.
3479 * @data: private data to be passed to @bio_ctr
3482 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3483 * The actual data parts of @rq_src (e.g. ->cmd, ->sense)
3484 * are not copied, and copying such parts is the caller's responsibility.
3485 * Also, pages which the original bios are pointing to are not copied
3486 * and the cloned bios just point same pages.
3487 * So cloned bios must be completed before original bios, which means
3488 * the caller must complete @rq before @rq_src.
3490 int blk_rq_prep_clone(struct request
*rq
, struct request
*rq_src
,
3491 struct bio_set
*bs
, gfp_t gfp_mask
,
3492 int (*bio_ctr
)(struct bio
*, struct bio
*, void *),
3495 struct bio
*bio
, *bio_src
;
3500 __rq_for_each_bio(bio_src
, rq_src
) {
3501 bio
= bio_clone_fast(bio_src
, gfp_mask
, bs
);
3505 if (bio_ctr
&& bio_ctr(bio
, bio_src
, data
))
3509 rq
->biotail
->bi_next
= bio
;
3512 rq
->bio
= rq
->biotail
= bio
;
3515 __blk_rq_prep_clone(rq
, rq_src
);
3522 blk_rq_unprep_clone(rq
);
3526 EXPORT_SYMBOL_GPL(blk_rq_prep_clone
);
3528 int kblockd_schedule_work(struct work_struct
*work
)
3530 return queue_work(kblockd_workqueue
, work
);
3532 EXPORT_SYMBOL(kblockd_schedule_work
);
3534 int kblockd_schedule_work_on(int cpu
, struct work_struct
*work
)
3536 return queue_work_on(cpu
, kblockd_workqueue
, work
);
3538 EXPORT_SYMBOL(kblockd_schedule_work_on
);
3540 int kblockd_mod_delayed_work_on(int cpu
, struct delayed_work
*dwork
,
3541 unsigned long delay
)
3543 return mod_delayed_work_on(cpu
, kblockd_workqueue
, dwork
, delay
);
3545 EXPORT_SYMBOL(kblockd_mod_delayed_work_on
);
3548 * blk_start_plug - initialize blk_plug and track it inside the task_struct
3549 * @plug: The &struct blk_plug that needs to be initialized
3552 * Tracking blk_plug inside the task_struct will help with auto-flushing the
3553 * pending I/O should the task end up blocking between blk_start_plug() and
3554 * blk_finish_plug(). This is important from a performance perspective, but
3555 * also ensures that we don't deadlock. For instance, if the task is blocking
3556 * for a memory allocation, memory reclaim could end up wanting to free a
3557 * page belonging to that request that is currently residing in our private
3558 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
3559 * this kind of deadlock.
3561 void blk_start_plug(struct blk_plug
*plug
)
3563 struct task_struct
*tsk
= current
;
3566 * If this is a nested plug, don't actually assign it.
3571 INIT_LIST_HEAD(&plug
->list
);
3572 INIT_LIST_HEAD(&plug
->mq_list
);
3573 INIT_LIST_HEAD(&plug
->cb_list
);
3575 * Store ordering should not be needed here, since a potential
3576 * preempt will imply a full memory barrier
3580 EXPORT_SYMBOL(blk_start_plug
);
3582 static int plug_rq_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
3584 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
3585 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
3587 return !(rqa
->q
< rqb
->q
||
3588 (rqa
->q
== rqb
->q
&& blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
3592 * If 'from_schedule' is true, then postpone the dispatch of requests
3593 * until a safe kblockd context. We due this to avoid accidental big
3594 * additional stack usage in driver dispatch, in places where the originally
3595 * plugger did not intend it.
3597 static void queue_unplugged(struct request_queue
*q
, unsigned int depth
,
3599 __releases(q
->queue_lock
)
3601 lockdep_assert_held(q
->queue_lock
);
3603 trace_block_unplug(q
, depth
, !from_schedule
);
3606 blk_run_queue_async(q
);
3609 spin_unlock(q
->queue_lock
);
3612 static void flush_plug_callbacks(struct blk_plug
*plug
, bool from_schedule
)
3614 LIST_HEAD(callbacks
);
3616 while (!list_empty(&plug
->cb_list
)) {
3617 list_splice_init(&plug
->cb_list
, &callbacks
);
3619 while (!list_empty(&callbacks
)) {
3620 struct blk_plug_cb
*cb
= list_first_entry(&callbacks
,
3623 list_del(&cb
->list
);
3624 cb
->callback(cb
, from_schedule
);
3629 struct blk_plug_cb
*blk_check_plugged(blk_plug_cb_fn unplug
, void *data
,
3632 struct blk_plug
*plug
= current
->plug
;
3633 struct blk_plug_cb
*cb
;
3638 list_for_each_entry(cb
, &plug
->cb_list
, list
)
3639 if (cb
->callback
== unplug
&& cb
->data
== data
)
3642 /* Not currently on the callback list */
3643 BUG_ON(size
< sizeof(*cb
));
3644 cb
= kzalloc(size
, GFP_ATOMIC
);
3647 cb
->callback
= unplug
;
3648 list_add(&cb
->list
, &plug
->cb_list
);
3652 EXPORT_SYMBOL(blk_check_plugged
);
3654 void blk_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
3656 struct request_queue
*q
;
3657 unsigned long flags
;
3662 flush_plug_callbacks(plug
, from_schedule
);
3664 if (!list_empty(&plug
->mq_list
))
3665 blk_mq_flush_plug_list(plug
, from_schedule
);
3667 if (list_empty(&plug
->list
))
3670 list_splice_init(&plug
->list
, &list
);
3672 list_sort(NULL
, &list
, plug_rq_cmp
);
3678 * Save and disable interrupts here, to avoid doing it for every
3679 * queue lock we have to take.
3681 local_irq_save(flags
);
3682 while (!list_empty(&list
)) {
3683 rq
= list_entry_rq(list
.next
);
3684 list_del_init(&rq
->queuelist
);
3688 * This drops the queue lock
3691 queue_unplugged(q
, depth
, from_schedule
);
3694 spin_lock(q
->queue_lock
);
3698 * Short-circuit if @q is dead
3700 if (unlikely(blk_queue_dying(q
))) {
3701 __blk_end_request_all(rq
, BLK_STS_IOERR
);
3706 * rq is already accounted, so use raw insert
3708 if (op_is_flush(rq
->cmd_flags
))
3709 __elv_add_request(q
, rq
, ELEVATOR_INSERT_FLUSH
);
3711 __elv_add_request(q
, rq
, ELEVATOR_INSERT_SORT_MERGE
);
3717 * This drops the queue lock
3720 queue_unplugged(q
, depth
, from_schedule
);
3722 local_irq_restore(flags
);
3725 void blk_finish_plug(struct blk_plug
*plug
)
3727 if (plug
!= current
->plug
)
3729 blk_flush_plug_list(plug
, false);
3731 current
->plug
= NULL
;
3733 EXPORT_SYMBOL(blk_finish_plug
);
3737 * blk_pm_runtime_init - Block layer runtime PM initialization routine
3738 * @q: the queue of the device
3739 * @dev: the device the queue belongs to
3742 * Initialize runtime-PM-related fields for @q and start auto suspend for
3743 * @dev. Drivers that want to take advantage of request-based runtime PM
3744 * should call this function after @dev has been initialized, and its
3745 * request queue @q has been allocated, and runtime PM for it can not happen
3746 * yet(either due to disabled/forbidden or its usage_count > 0). In most
3747 * cases, driver should call this function before any I/O has taken place.
3749 * This function takes care of setting up using auto suspend for the device,
3750 * the autosuspend delay is set to -1 to make runtime suspend impossible
3751 * until an updated value is either set by user or by driver. Drivers do
3752 * not need to touch other autosuspend settings.
3754 * The block layer runtime PM is request based, so only works for drivers
3755 * that use request as their IO unit instead of those directly use bio's.
3757 void blk_pm_runtime_init(struct request_queue
*q
, struct device
*dev
)
3759 /* not support for RQF_PM and ->rpm_status in blk-mq yet */
3764 q
->rpm_status
= RPM_ACTIVE
;
3765 pm_runtime_set_autosuspend_delay(q
->dev
, -1);
3766 pm_runtime_use_autosuspend(q
->dev
);
3768 EXPORT_SYMBOL(blk_pm_runtime_init
);
3771 * blk_pre_runtime_suspend - Pre runtime suspend check
3772 * @q: the queue of the device
3775 * This function will check if runtime suspend is allowed for the device
3776 * by examining if there are any requests pending in the queue. If there
3777 * are requests pending, the device can not be runtime suspended; otherwise,
3778 * the queue's status will be updated to SUSPENDING and the driver can
3779 * proceed to suspend the device.
3781 * For the not allowed case, we mark last busy for the device so that
3782 * runtime PM core will try to autosuspend it some time later.
3784 * This function should be called near the start of the device's
3785 * runtime_suspend callback.
3788 * 0 - OK to runtime suspend the device
3789 * -EBUSY - Device should not be runtime suspended
3791 int blk_pre_runtime_suspend(struct request_queue
*q
)
3798 spin_lock_irq(q
->queue_lock
);
3799 if (q
->nr_pending
) {
3801 pm_runtime_mark_last_busy(q
->dev
);
3803 q
->rpm_status
= RPM_SUSPENDING
;
3805 spin_unlock_irq(q
->queue_lock
);
3808 EXPORT_SYMBOL(blk_pre_runtime_suspend
);
3811 * blk_post_runtime_suspend - Post runtime suspend processing
3812 * @q: the queue of the device
3813 * @err: return value of the device's runtime_suspend function
3816 * Update the queue's runtime status according to the return value of the
3817 * device's runtime suspend function and mark last busy for the device so
3818 * that PM core will try to auto suspend the device at a later time.
3820 * This function should be called near the end of the device's
3821 * runtime_suspend callback.
3823 void blk_post_runtime_suspend(struct request_queue
*q
, int err
)
3828 spin_lock_irq(q
->queue_lock
);
3830 q
->rpm_status
= RPM_SUSPENDED
;
3832 q
->rpm_status
= RPM_ACTIVE
;
3833 pm_runtime_mark_last_busy(q
->dev
);
3835 spin_unlock_irq(q
->queue_lock
);
3837 EXPORT_SYMBOL(blk_post_runtime_suspend
);
3840 * blk_pre_runtime_resume - Pre runtime resume processing
3841 * @q: the queue of the device
3844 * Update the queue's runtime status to RESUMING in preparation for the
3845 * runtime resume of the device.
3847 * This function should be called near the start of the device's
3848 * runtime_resume callback.
3850 void blk_pre_runtime_resume(struct request_queue
*q
)
3855 spin_lock_irq(q
->queue_lock
);
3856 q
->rpm_status
= RPM_RESUMING
;
3857 spin_unlock_irq(q
->queue_lock
);
3859 EXPORT_SYMBOL(blk_pre_runtime_resume
);
3862 * blk_post_runtime_resume - Post runtime resume processing
3863 * @q: the queue of the device
3864 * @err: return value of the device's runtime_resume function
3867 * Update the queue's runtime status according to the return value of the
3868 * device's runtime_resume function. If it is successfully resumed, process
3869 * the requests that are queued into the device's queue when it is resuming
3870 * and then mark last busy and initiate autosuspend for it.
3872 * This function should be called near the end of the device's
3873 * runtime_resume callback.
3875 void blk_post_runtime_resume(struct request_queue
*q
, int err
)
3880 spin_lock_irq(q
->queue_lock
);
3882 q
->rpm_status
= RPM_ACTIVE
;
3884 pm_runtime_mark_last_busy(q
->dev
);
3885 pm_request_autosuspend(q
->dev
);
3887 q
->rpm_status
= RPM_SUSPENDED
;
3889 spin_unlock_irq(q
->queue_lock
);
3891 EXPORT_SYMBOL(blk_post_runtime_resume
);
3894 * blk_set_runtime_active - Force runtime status of the queue to be active
3895 * @q: the queue of the device
3897 * If the device is left runtime suspended during system suspend the resume
3898 * hook typically resumes the device and corrects runtime status
3899 * accordingly. However, that does not affect the queue runtime PM status
3900 * which is still "suspended". This prevents processing requests from the
3903 * This function can be used in driver's resume hook to correct queue
3904 * runtime PM status and re-enable peeking requests from the queue. It
3905 * should be called before first request is added to the queue.
3907 void blk_set_runtime_active(struct request_queue
*q
)
3909 spin_lock_irq(q
->queue_lock
);
3910 q
->rpm_status
= RPM_ACTIVE
;
3911 pm_runtime_mark_last_busy(q
->dev
);
3912 pm_request_autosuspend(q
->dev
);
3913 spin_unlock_irq(q
->queue_lock
);
3915 EXPORT_SYMBOL(blk_set_runtime_active
);
3918 int __init
blk_dev_init(void)
3920 BUILD_BUG_ON(REQ_OP_LAST
>= (1 << REQ_OP_BITS
));
3921 BUILD_BUG_ON(REQ_OP_BITS
+ REQ_FLAG_BITS
> 8 *
3922 FIELD_SIZEOF(struct request
, cmd_flags
));
3923 BUILD_BUG_ON(REQ_OP_BITS
+ REQ_FLAG_BITS
> 8 *
3924 FIELD_SIZEOF(struct bio
, bi_opf
));
3926 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
3927 kblockd_workqueue
= alloc_workqueue("kblockd",
3928 WQ_MEM_RECLAIM
| WQ_HIGHPRI
, 0);
3929 if (!kblockd_workqueue
)
3930 panic("Failed to create kblockd\n");
3932 request_cachep
= kmem_cache_create("blkdev_requests",
3933 sizeof(struct request
), 0, SLAB_PANIC
, NULL
);
3935 blk_requestq_cachep
= kmem_cache_create("request_queue",
3936 sizeof(struct request_queue
), 0, SLAB_PANIC
, NULL
);
3938 #ifdef CONFIG_DEBUG_FS
3939 blk_debugfs_root
= debugfs_create_dir("block", NULL
);