2 * Block multiqueue core code
4 * Copyright (C) 2013-2014 Jens Axboe
5 * Copyright (C) 2013-2014 Christoph Hellwig
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/backing-dev.h>
10 #include <linux/bio.h>
11 #include <linux/blkdev.h>
12 #include <linux/kmemleak.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/workqueue.h>
17 #include <linux/smp.h>
18 #include <linux/llist.h>
19 #include <linux/list_sort.h>
20 #include <linux/cpu.h>
21 #include <linux/cache.h>
22 #include <linux/sched/sysctl.h>
23 #include <linux/delay.h>
24 #include <linux/crash_dump.h>
26 #include <trace/events/block.h>
28 #include <linux/blk-mq.h>
31 #include "blk-mq-tag.h"
33 static DEFINE_MUTEX(all_q_mutex
);
34 static LIST_HEAD(all_q_list
);
36 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
39 * Check if any of the ctx's have pending work in this hardware queue
41 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
45 for (i
= 0; i
< hctx
->ctx_map
.size
; i
++)
46 if (hctx
->ctx_map
.map
[i
].word
)
52 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
53 struct blk_mq_ctx
*ctx
)
55 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
58 #define CTX_TO_BIT(hctx, ctx) \
59 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
62 * Mark this ctx as having pending work in this hardware queue
64 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
65 struct blk_mq_ctx
*ctx
)
67 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
69 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
70 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
73 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
74 struct blk_mq_ctx
*ctx
)
76 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
78 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
81 void blk_mq_freeze_queue_start(struct request_queue
*q
)
85 freeze_depth
= atomic_inc_return(&q
->mq_freeze_depth
);
86 if (freeze_depth
== 1) {
87 percpu_ref_kill(&q
->q_usage_counter
);
88 blk_mq_run_hw_queues(q
, false);
91 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start
);
93 static void blk_mq_freeze_queue_wait(struct request_queue
*q
)
95 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
99 * Guarantee no request is in use, so we can change any data structure of
100 * the queue afterward.
102 void blk_freeze_queue(struct request_queue
*q
)
105 * In the !blk_mq case we are only calling this to kill the
106 * q_usage_counter, otherwise this increases the freeze depth
107 * and waits for it to return to zero. For this reason there is
108 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
109 * exported to drivers as the only user for unfreeze is blk_mq.
111 blk_mq_freeze_queue_start(q
);
112 blk_mq_freeze_queue_wait(q
);
115 void blk_mq_freeze_queue(struct request_queue
*q
)
118 * ...just an alias to keep freeze and unfreeze actions balanced
119 * in the blk_mq_* namespace
123 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
125 void blk_mq_unfreeze_queue(struct request_queue
*q
)
129 freeze_depth
= atomic_dec_return(&q
->mq_freeze_depth
);
130 WARN_ON_ONCE(freeze_depth
< 0);
132 percpu_ref_reinit(&q
->q_usage_counter
);
133 wake_up_all(&q
->mq_freeze_wq
);
136 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
138 void blk_mq_wake_waiters(struct request_queue
*q
)
140 struct blk_mq_hw_ctx
*hctx
;
143 queue_for_each_hw_ctx(q
, hctx
, i
)
144 if (blk_mq_hw_queue_mapped(hctx
))
145 blk_mq_tag_wakeup_all(hctx
->tags
, true);
148 * If we are called because the queue has now been marked as
149 * dying, we need to ensure that processes currently waiting on
150 * the queue are notified as well.
152 wake_up_all(&q
->mq_freeze_wq
);
155 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
157 return blk_mq_has_free_tags(hctx
->tags
);
159 EXPORT_SYMBOL(blk_mq_can_queue
);
161 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
162 struct request
*rq
, int op
,
163 unsigned int op_flags
)
165 if (blk_queue_io_stat(q
))
166 op_flags
|= REQ_IO_STAT
;
168 INIT_LIST_HEAD(&rq
->queuelist
);
169 /* csd/requeue_work/fifo_time is initialized before use */
172 req_set_op_attrs(rq
, op
, op_flags
);
173 /* do not touch atomic flags, it needs atomic ops against the timer */
175 INIT_HLIST_NODE(&rq
->hash
);
176 RB_CLEAR_NODE(&rq
->rb_node
);
179 rq
->start_time
= jiffies
;
180 #ifdef CONFIG_BLK_CGROUP
182 set_start_time_ns(rq
);
183 rq
->io_start_time_ns
= 0;
185 rq
->nr_phys_segments
= 0;
186 #if defined(CONFIG_BLK_DEV_INTEGRITY)
187 rq
->nr_integrity_segments
= 0;
190 /* tag was already set */
200 INIT_LIST_HEAD(&rq
->timeout_list
);
204 rq
->end_io_data
= NULL
;
207 ctx
->rq_dispatched
[rw_is_sync(op
, op_flags
)]++;
210 static struct request
*
211 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int op
, int op_flags
)
216 tag
= blk_mq_get_tag(data
);
217 if (tag
!= BLK_MQ_TAG_FAIL
) {
218 rq
= data
->hctx
->tags
->rqs
[tag
];
220 if (blk_mq_tag_busy(data
->hctx
)) {
221 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
222 atomic_inc(&data
->hctx
->nr_active
);
226 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, op
, op_flags
);
233 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
,
236 struct blk_mq_ctx
*ctx
;
237 struct blk_mq_hw_ctx
*hctx
;
239 struct blk_mq_alloc_data alloc_data
;
242 ret
= blk_queue_enter(q
, flags
& BLK_MQ_REQ_NOWAIT
);
246 ctx
= blk_mq_get_ctx(q
);
247 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
248 blk_mq_set_alloc_data(&alloc_data
, q
, flags
, ctx
, hctx
);
250 rq
= __blk_mq_alloc_request(&alloc_data
, rw
, 0);
251 if (!rq
&& !(flags
& BLK_MQ_REQ_NOWAIT
)) {
252 __blk_mq_run_hw_queue(hctx
);
255 ctx
= blk_mq_get_ctx(q
);
256 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
257 blk_mq_set_alloc_data(&alloc_data
, q
, flags
, ctx
, hctx
);
258 rq
= __blk_mq_alloc_request(&alloc_data
, rw
, 0);
259 ctx
= alloc_data
.ctx
;
264 return ERR_PTR(-EWOULDBLOCK
);
268 rq
->__sector
= (sector_t
) -1;
269 rq
->bio
= rq
->biotail
= NULL
;
272 EXPORT_SYMBOL(blk_mq_alloc_request
);
274 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
, int rw
,
275 unsigned int flags
, unsigned int hctx_idx
)
277 struct blk_mq_hw_ctx
*hctx
;
278 struct blk_mq_ctx
*ctx
;
280 struct blk_mq_alloc_data alloc_data
;
284 * If the tag allocator sleeps we could get an allocation for a
285 * different hardware context. No need to complicate the low level
286 * allocator for this for the rare use case of a command tied to
289 if (WARN_ON_ONCE(!(flags
& BLK_MQ_REQ_NOWAIT
)))
290 return ERR_PTR(-EINVAL
);
292 if (hctx_idx
>= q
->nr_hw_queues
)
293 return ERR_PTR(-EIO
);
295 ret
= blk_queue_enter(q
, true);
299 hctx
= q
->queue_hw_ctx
[hctx_idx
];
300 ctx
= __blk_mq_get_ctx(q
, cpumask_first(hctx
->cpumask
));
302 blk_mq_set_alloc_data(&alloc_data
, q
, flags
, ctx
, hctx
);
303 rq
= __blk_mq_alloc_request(&alloc_data
, rw
, 0);
306 return ERR_PTR(-EWOULDBLOCK
);
311 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
313 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
314 struct blk_mq_ctx
*ctx
, struct request
*rq
)
316 const int tag
= rq
->tag
;
317 struct request_queue
*q
= rq
->q
;
319 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
320 atomic_dec(&hctx
->nr_active
);
323 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
324 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
328 void blk_mq_free_hctx_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
330 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
332 ctx
->rq_completed
[rq_is_sync(rq
)]++;
333 __blk_mq_free_request(hctx
, ctx
, rq
);
336 EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request
);
338 void blk_mq_free_request(struct request
*rq
)
340 struct blk_mq_hw_ctx
*hctx
;
341 struct request_queue
*q
= rq
->q
;
343 hctx
= q
->mq_ops
->map_queue(q
, rq
->mq_ctx
->cpu
);
344 blk_mq_free_hctx_request(hctx
, rq
);
346 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
348 inline void __blk_mq_end_request(struct request
*rq
, int error
)
350 blk_account_io_done(rq
);
353 rq
->end_io(rq
, error
);
355 if (unlikely(blk_bidi_rq(rq
)))
356 blk_mq_free_request(rq
->next_rq
);
357 blk_mq_free_request(rq
);
360 EXPORT_SYMBOL(__blk_mq_end_request
);
362 void blk_mq_end_request(struct request
*rq
, int error
)
364 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
366 __blk_mq_end_request(rq
, error
);
368 EXPORT_SYMBOL(blk_mq_end_request
);
370 static void __blk_mq_complete_request_remote(void *data
)
372 struct request
*rq
= data
;
374 rq
->q
->softirq_done_fn(rq
);
377 static void blk_mq_ipi_complete_request(struct request
*rq
)
379 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
383 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
384 rq
->q
->softirq_done_fn(rq
);
389 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
390 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
392 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
393 rq
->csd
.func
= __blk_mq_complete_request_remote
;
396 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
398 rq
->q
->softirq_done_fn(rq
);
403 static void __blk_mq_complete_request(struct request
*rq
)
405 struct request_queue
*q
= rq
->q
;
407 if (!q
->softirq_done_fn
)
408 blk_mq_end_request(rq
, rq
->errors
);
410 blk_mq_ipi_complete_request(rq
);
414 * blk_mq_complete_request - end I/O on a request
415 * @rq: the request being processed
418 * Ends all I/O on a request. It does not handle partial completions.
419 * The actual completion happens out-of-order, through a IPI handler.
421 void blk_mq_complete_request(struct request
*rq
, int error
)
423 struct request_queue
*q
= rq
->q
;
425 if (unlikely(blk_should_fake_timeout(q
)))
427 if (!blk_mark_rq_complete(rq
)) {
429 __blk_mq_complete_request(rq
);
432 EXPORT_SYMBOL(blk_mq_complete_request
);
434 int blk_mq_request_started(struct request
*rq
)
436 return test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
438 EXPORT_SYMBOL_GPL(blk_mq_request_started
);
440 void blk_mq_start_request(struct request
*rq
)
442 struct request_queue
*q
= rq
->q
;
444 trace_block_rq_issue(q
, rq
);
446 rq
->resid_len
= blk_rq_bytes(rq
);
447 if (unlikely(blk_bidi_rq(rq
)))
448 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
453 * Ensure that ->deadline is visible before set the started
454 * flag and clear the completed flag.
456 smp_mb__before_atomic();
459 * Mark us as started and clear complete. Complete might have been
460 * set if requeue raced with timeout, which then marked it as
461 * complete. So be sure to clear complete again when we start
462 * the request, otherwise we'll ignore the completion event.
464 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
465 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
466 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
467 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
469 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
471 * Make sure space for the drain appears. We know we can do
472 * this because max_hw_segments has been adjusted to be one
473 * fewer than the device can handle.
475 rq
->nr_phys_segments
++;
478 EXPORT_SYMBOL(blk_mq_start_request
);
480 static void __blk_mq_requeue_request(struct request
*rq
)
482 struct request_queue
*q
= rq
->q
;
484 trace_block_rq_requeue(q
, rq
);
486 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
487 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
488 rq
->nr_phys_segments
--;
492 void blk_mq_requeue_request(struct request
*rq
)
494 __blk_mq_requeue_request(rq
);
496 BUG_ON(blk_queued_rq(rq
));
497 blk_mq_add_to_requeue_list(rq
, true);
499 EXPORT_SYMBOL(blk_mq_requeue_request
);
501 static void blk_mq_requeue_work(struct work_struct
*work
)
503 struct request_queue
*q
=
504 container_of(work
, struct request_queue
, requeue_work
);
506 struct request
*rq
, *next
;
509 spin_lock_irqsave(&q
->requeue_lock
, flags
);
510 list_splice_init(&q
->requeue_list
, &rq_list
);
511 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
513 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
514 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
517 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
518 list_del_init(&rq
->queuelist
);
519 blk_mq_insert_request(rq
, true, false, false);
522 while (!list_empty(&rq_list
)) {
523 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
524 list_del_init(&rq
->queuelist
);
525 blk_mq_insert_request(rq
, false, false, false);
529 * Use the start variant of queue running here, so that running
530 * the requeue work will kick stopped queues.
532 blk_mq_start_hw_queues(q
);
535 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
537 struct request_queue
*q
= rq
->q
;
541 * We abuse this flag that is otherwise used by the I/O scheduler to
542 * request head insertation from the workqueue.
544 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
546 spin_lock_irqsave(&q
->requeue_lock
, flags
);
548 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
549 list_add(&rq
->queuelist
, &q
->requeue_list
);
551 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
553 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
555 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
557 void blk_mq_cancel_requeue_work(struct request_queue
*q
)
559 cancel_work_sync(&q
->requeue_work
);
561 EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work
);
563 void blk_mq_kick_requeue_list(struct request_queue
*q
)
565 kblockd_schedule_work(&q
->requeue_work
);
567 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
569 void blk_mq_abort_requeue_list(struct request_queue
*q
)
574 spin_lock_irqsave(&q
->requeue_lock
, flags
);
575 list_splice_init(&q
->requeue_list
, &rq_list
);
576 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
578 while (!list_empty(&rq_list
)) {
581 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
582 list_del_init(&rq
->queuelist
);
584 blk_mq_end_request(rq
, rq
->errors
);
587 EXPORT_SYMBOL(blk_mq_abort_requeue_list
);
589 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
591 if (tag
< tags
->nr_tags
)
592 return tags
->rqs
[tag
];
596 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
598 struct blk_mq_timeout_data
{
600 unsigned int next_set
;
603 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
605 struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
606 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
609 * We know that complete is set at this point. If STARTED isn't set
610 * anymore, then the request isn't active and the "timeout" should
611 * just be ignored. This can happen due to the bitflag ordering.
612 * Timeout first checks if STARTED is set, and if it is, assumes
613 * the request is active. But if we race with completion, then
614 * we both flags will get cleared. So check here again, and ignore
615 * a timeout event with a request that isn't active.
617 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
621 ret
= ops
->timeout(req
, reserved
);
625 __blk_mq_complete_request(req
);
627 case BLK_EH_RESET_TIMER
:
629 blk_clear_rq_complete(req
);
631 case BLK_EH_NOT_HANDLED
:
634 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
639 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
640 struct request
*rq
, void *priv
, bool reserved
)
642 struct blk_mq_timeout_data
*data
= priv
;
644 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
646 * If a request wasn't started before the queue was
647 * marked dying, kill it here or it'll go unnoticed.
649 if (unlikely(blk_queue_dying(rq
->q
))) {
651 blk_mq_end_request(rq
, rq
->errors
);
656 if (time_after_eq(jiffies
, rq
->deadline
)) {
657 if (!blk_mark_rq_complete(rq
))
658 blk_mq_rq_timed_out(rq
, reserved
);
659 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
660 data
->next
= rq
->deadline
;
665 static void blk_mq_timeout_work(struct work_struct
*work
)
667 struct request_queue
*q
=
668 container_of(work
, struct request_queue
, timeout_work
);
669 struct blk_mq_timeout_data data
= {
675 if (blk_queue_enter(q
, true))
678 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &data
);
681 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
682 mod_timer(&q
->timeout
, data
.next
);
684 struct blk_mq_hw_ctx
*hctx
;
686 queue_for_each_hw_ctx(q
, hctx
, i
) {
687 /* the hctx may be unmapped, so check it here */
688 if (blk_mq_hw_queue_mapped(hctx
))
689 blk_mq_tag_idle(hctx
);
696 * Reverse check our software queue for entries that we could potentially
697 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
698 * too much time checking for merges.
700 static bool blk_mq_attempt_merge(struct request_queue
*q
,
701 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
706 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
712 if (!blk_rq_merge_ok(rq
, bio
))
715 el_ret
= blk_try_merge(rq
, bio
);
716 if (el_ret
== ELEVATOR_BACK_MERGE
) {
717 if (bio_attempt_back_merge(q
, rq
, bio
)) {
722 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
723 if (bio_attempt_front_merge(q
, rq
, bio
)) {
735 * Process software queues that have been marked busy, splicing them
736 * to the for-dispatch
738 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
740 struct blk_mq_ctx
*ctx
;
743 for (i
= 0; i
< hctx
->ctx_map
.size
; i
++) {
744 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
745 unsigned int off
, bit
;
751 off
= i
* hctx
->ctx_map
.bits_per_word
;
753 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
754 if (bit
>= bm
->depth
)
757 ctx
= hctx
->ctxs
[bit
+ off
];
758 clear_bit(bit
, &bm
->word
);
759 spin_lock(&ctx
->lock
);
760 list_splice_tail_init(&ctx
->rq_list
, list
);
761 spin_unlock(&ctx
->lock
);
769 * Run this hardware queue, pulling any software queues mapped to it in.
770 * Note that this function currently has various problems around ordering
771 * of IO. In particular, we'd like FIFO behaviour on handling existing
772 * items on the hctx->dispatch list. Ignore that for now.
774 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
776 struct request_queue
*q
= hctx
->queue
;
779 LIST_HEAD(driver_list
);
780 struct list_head
*dptr
;
783 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
785 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
791 * Touch any software queue that has pending entries.
793 flush_busy_ctxs(hctx
, &rq_list
);
796 * If we have previous entries on our dispatch list, grab them
797 * and stuff them at the front for more fair dispatch.
799 if (!list_empty_careful(&hctx
->dispatch
)) {
800 spin_lock(&hctx
->lock
);
801 if (!list_empty(&hctx
->dispatch
))
802 list_splice_init(&hctx
->dispatch
, &rq_list
);
803 spin_unlock(&hctx
->lock
);
807 * Start off with dptr being NULL, so we start the first request
808 * immediately, even if we have more pending.
813 * Now process all the entries, sending them to the driver.
816 while (!list_empty(&rq_list
)) {
817 struct blk_mq_queue_data bd
;
820 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
821 list_del_init(&rq
->queuelist
);
825 bd
.last
= list_empty(&rq_list
);
827 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
829 case BLK_MQ_RQ_QUEUE_OK
:
832 case BLK_MQ_RQ_QUEUE_BUSY
:
833 list_add(&rq
->queuelist
, &rq_list
);
834 __blk_mq_requeue_request(rq
);
837 pr_err("blk-mq: bad return on queue: %d\n", ret
);
838 case BLK_MQ_RQ_QUEUE_ERROR
:
840 blk_mq_end_request(rq
, rq
->errors
);
844 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
848 * We've done the first request. If we have more than 1
849 * left in the list, set dptr to defer issue.
851 if (!dptr
&& rq_list
.next
!= rq_list
.prev
)
856 hctx
->dispatched
[0]++;
857 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
858 hctx
->dispatched
[ilog2(queued
) + 1]++;
861 * Any items that need requeuing? Stuff them into hctx->dispatch,
862 * that is where we will continue on next queue run.
864 if (!list_empty(&rq_list
)) {
865 spin_lock(&hctx
->lock
);
866 list_splice(&rq_list
, &hctx
->dispatch
);
867 spin_unlock(&hctx
->lock
);
869 * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
870 * it's possible the queue is stopped and restarted again
871 * before this. Queue restart will dispatch requests. And since
872 * requests in rq_list aren't added into hctx->dispatch yet,
873 * the requests in rq_list might get lost.
875 * blk_mq_run_hw_queue() already checks the STOPPED bit
877 blk_mq_run_hw_queue(hctx
, true);
882 * It'd be great if the workqueue API had a way to pass
883 * in a mask and had some smarts for more clever placement.
884 * For now we just round-robin here, switching for every
885 * BLK_MQ_CPU_WORK_BATCH queued items.
887 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
889 if (hctx
->queue
->nr_hw_queues
== 1)
890 return WORK_CPU_UNBOUND
;
892 if (--hctx
->next_cpu_batch
<= 0) {
893 int cpu
= hctx
->next_cpu
, next_cpu
;
895 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
896 if (next_cpu
>= nr_cpu_ids
)
897 next_cpu
= cpumask_first(hctx
->cpumask
);
899 hctx
->next_cpu
= next_cpu
;
900 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
905 return hctx
->next_cpu
;
908 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
910 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
) ||
911 !blk_mq_hw_queue_mapped(hctx
)))
916 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
917 __blk_mq_run_hw_queue(hctx
);
925 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
929 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
931 struct blk_mq_hw_ctx
*hctx
;
934 queue_for_each_hw_ctx(q
, hctx
, i
) {
935 if ((!blk_mq_hctx_has_pending(hctx
) &&
936 list_empty_careful(&hctx
->dispatch
)) ||
937 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
940 blk_mq_run_hw_queue(hctx
, async
);
943 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
945 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
947 cancel_delayed_work(&hctx
->run_work
);
948 cancel_delayed_work(&hctx
->delay_work
);
949 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
951 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
953 void blk_mq_stop_hw_queues(struct request_queue
*q
)
955 struct blk_mq_hw_ctx
*hctx
;
958 queue_for_each_hw_ctx(q
, hctx
, i
)
959 blk_mq_stop_hw_queue(hctx
);
961 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
963 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
965 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
967 blk_mq_run_hw_queue(hctx
, false);
969 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
971 void blk_mq_start_hw_queues(struct request_queue
*q
)
973 struct blk_mq_hw_ctx
*hctx
;
976 queue_for_each_hw_ctx(q
, hctx
, i
)
977 blk_mq_start_hw_queue(hctx
);
979 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
981 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
983 struct blk_mq_hw_ctx
*hctx
;
986 queue_for_each_hw_ctx(q
, hctx
, i
) {
987 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
990 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
991 blk_mq_run_hw_queue(hctx
, async
);
994 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
996 static void blk_mq_run_work_fn(struct work_struct
*work
)
998 struct blk_mq_hw_ctx
*hctx
;
1000 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
1002 __blk_mq_run_hw_queue(hctx
);
1005 static void blk_mq_delay_work_fn(struct work_struct
*work
)
1007 struct blk_mq_hw_ctx
*hctx
;
1009 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
1011 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
1012 __blk_mq_run_hw_queue(hctx
);
1015 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1017 if (unlikely(!blk_mq_hw_queue_mapped(hctx
)))
1020 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1021 &hctx
->delay_work
, msecs_to_jiffies(msecs
));
1023 EXPORT_SYMBOL(blk_mq_delay_queue
);
1025 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
1026 struct blk_mq_ctx
*ctx
,
1030 trace_block_rq_insert(hctx
->queue
, rq
);
1033 list_add(&rq
->queuelist
, &ctx
->rq_list
);
1035 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
1038 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
1039 struct request
*rq
, bool at_head
)
1041 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1043 __blk_mq_insert_req_list(hctx
, ctx
, rq
, at_head
);
1044 blk_mq_hctx_mark_pending(hctx
, ctx
);
1047 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
1050 struct request_queue
*q
= rq
->q
;
1051 struct blk_mq_hw_ctx
*hctx
;
1052 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
1054 current_ctx
= blk_mq_get_ctx(q
);
1055 if (!cpu_online(ctx
->cpu
))
1056 rq
->mq_ctx
= ctx
= current_ctx
;
1058 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1060 spin_lock(&ctx
->lock
);
1061 __blk_mq_insert_request(hctx
, rq
, at_head
);
1062 spin_unlock(&ctx
->lock
);
1065 blk_mq_run_hw_queue(hctx
, async
);
1067 blk_mq_put_ctx(current_ctx
);
1070 static void blk_mq_insert_requests(struct request_queue
*q
,
1071 struct blk_mq_ctx
*ctx
,
1072 struct list_head
*list
,
1077 struct blk_mq_hw_ctx
*hctx
;
1078 struct blk_mq_ctx
*current_ctx
;
1080 trace_block_unplug(q
, depth
, !from_schedule
);
1082 current_ctx
= blk_mq_get_ctx(q
);
1084 if (!cpu_online(ctx
->cpu
))
1086 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1089 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1092 spin_lock(&ctx
->lock
);
1093 while (!list_empty(list
)) {
1096 rq
= list_first_entry(list
, struct request
, queuelist
);
1097 list_del_init(&rq
->queuelist
);
1099 __blk_mq_insert_req_list(hctx
, ctx
, rq
, false);
1101 blk_mq_hctx_mark_pending(hctx
, ctx
);
1102 spin_unlock(&ctx
->lock
);
1104 blk_mq_run_hw_queue(hctx
, from_schedule
);
1105 blk_mq_put_ctx(current_ctx
);
1108 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1110 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1111 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1113 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1114 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1115 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1118 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1120 struct blk_mq_ctx
*this_ctx
;
1121 struct request_queue
*this_q
;
1124 LIST_HEAD(ctx_list
);
1127 list_splice_init(&plug
->mq_list
, &list
);
1129 list_sort(NULL
, &list
, plug_ctx_cmp
);
1135 while (!list_empty(&list
)) {
1136 rq
= list_entry_rq(list
.next
);
1137 list_del_init(&rq
->queuelist
);
1139 if (rq
->mq_ctx
!= this_ctx
) {
1141 blk_mq_insert_requests(this_q
, this_ctx
,
1146 this_ctx
= rq
->mq_ctx
;
1152 list_add_tail(&rq
->queuelist
, &ctx_list
);
1156 * If 'this_ctx' is set, we know we have entries to complete
1157 * on 'ctx_list'. Do those.
1160 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1165 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1167 init_request_from_bio(rq
, bio
);
1169 blk_account_io_start(rq
, 1);
1172 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1174 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1175 !blk_queue_nomerges(hctx
->queue
);
1178 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1179 struct blk_mq_ctx
*ctx
,
1180 struct request
*rq
, struct bio
*bio
)
1182 if (!hctx_allow_merges(hctx
) || !bio_mergeable(bio
)) {
1183 blk_mq_bio_to_request(rq
, bio
);
1184 spin_lock(&ctx
->lock
);
1186 __blk_mq_insert_request(hctx
, rq
, false);
1187 spin_unlock(&ctx
->lock
);
1190 struct request_queue
*q
= hctx
->queue
;
1192 spin_lock(&ctx
->lock
);
1193 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1194 blk_mq_bio_to_request(rq
, bio
);
1198 spin_unlock(&ctx
->lock
);
1199 __blk_mq_free_request(hctx
, ctx
, rq
);
1204 struct blk_map_ctx
{
1205 struct blk_mq_hw_ctx
*hctx
;
1206 struct blk_mq_ctx
*ctx
;
1209 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1211 struct blk_map_ctx
*data
)
1213 struct blk_mq_hw_ctx
*hctx
;
1214 struct blk_mq_ctx
*ctx
;
1216 int op
= bio_data_dir(bio
);
1218 struct blk_mq_alloc_data alloc_data
;
1220 blk_queue_enter_live(q
);
1221 ctx
= blk_mq_get_ctx(q
);
1222 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1224 if (rw_is_sync(bio_op(bio
), bio
->bi_rw
))
1225 op_flags
|= REQ_SYNC
;
1227 trace_block_getrq(q
, bio
, op
);
1228 blk_mq_set_alloc_data(&alloc_data
, q
, BLK_MQ_REQ_NOWAIT
, ctx
, hctx
);
1229 rq
= __blk_mq_alloc_request(&alloc_data
, op
, op_flags
);
1230 if (unlikely(!rq
)) {
1231 __blk_mq_run_hw_queue(hctx
);
1232 blk_mq_put_ctx(ctx
);
1233 trace_block_sleeprq(q
, bio
, op
);
1235 ctx
= blk_mq_get_ctx(q
);
1236 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1237 blk_mq_set_alloc_data(&alloc_data
, q
, 0, ctx
, hctx
);
1238 rq
= __blk_mq_alloc_request(&alloc_data
, op
, op_flags
);
1239 ctx
= alloc_data
.ctx
;
1240 hctx
= alloc_data
.hctx
;
1249 static int blk_mq_direct_issue_request(struct request
*rq
, blk_qc_t
*cookie
)
1252 struct request_queue
*q
= rq
->q
;
1253 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
,
1255 struct blk_mq_queue_data bd
= {
1260 blk_qc_t new_cookie
= blk_tag_to_qc_t(rq
->tag
, hctx
->queue_num
);
1263 * For OK queue, we are done. For error, kill it. Any other
1264 * error (busy), just add it to our list as we previously
1267 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1268 if (ret
== BLK_MQ_RQ_QUEUE_OK
) {
1269 *cookie
= new_cookie
;
1273 __blk_mq_requeue_request(rq
);
1275 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1276 *cookie
= BLK_QC_T_NONE
;
1278 blk_mq_end_request(rq
, rq
->errors
);
1286 * Multiple hardware queue variant. This will not use per-process plugs,
1287 * but will attempt to bypass the hctx queueing if we can go straight to
1288 * hardware for SYNC IO.
1290 static blk_qc_t
blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1292 const int is_sync
= rw_is_sync(bio_op(bio
), bio
->bi_rw
);
1293 const int is_flush_fua
= bio
->bi_rw
& (REQ_PREFLUSH
| REQ_FUA
);
1294 struct blk_map_ctx data
;
1296 unsigned int request_count
= 0;
1297 struct blk_plug
*plug
;
1298 struct request
*same_queue_rq
= NULL
;
1301 blk_queue_bounce(q
, &bio
);
1303 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1305 return BLK_QC_T_NONE
;
1308 blk_queue_split(q
, &bio
, q
->bio_split
);
1310 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1311 blk_attempt_plug_merge(q
, bio
, &request_count
, &same_queue_rq
))
1312 return BLK_QC_T_NONE
;
1314 rq
= blk_mq_map_request(q
, bio
, &data
);
1316 return BLK_QC_T_NONE
;
1318 cookie
= blk_tag_to_qc_t(rq
->tag
, data
.hctx
->queue_num
);
1320 if (unlikely(is_flush_fua
)) {
1321 blk_mq_bio_to_request(rq
, bio
);
1322 blk_insert_flush(rq
);
1326 plug
= current
->plug
;
1328 * If the driver supports defer issued based on 'last', then
1329 * queue it up like normal since we can potentially save some
1332 if (((plug
&& !blk_queue_nomerges(q
)) || is_sync
) &&
1333 !(data
.hctx
->flags
& BLK_MQ_F_DEFER_ISSUE
)) {
1334 struct request
*old_rq
= NULL
;
1336 blk_mq_bio_to_request(rq
, bio
);
1339 * We do limited pluging. If the bio can be merged, do that.
1340 * Otherwise the existing request in the plug list will be
1341 * issued. So the plug list will have one request at most
1345 * The plug list might get flushed before this. If that
1346 * happens, same_queue_rq is invalid and plug list is
1349 if (same_queue_rq
&& !list_empty(&plug
->mq_list
)) {
1350 old_rq
= same_queue_rq
;
1351 list_del_init(&old_rq
->queuelist
);
1353 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1354 } else /* is_sync */
1356 blk_mq_put_ctx(data
.ctx
);
1359 if (!blk_mq_direct_issue_request(old_rq
, &cookie
))
1361 blk_mq_insert_request(old_rq
, false, true, true);
1365 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1367 * For a SYNC request, send it to the hardware immediately. For
1368 * an ASYNC request, just ensure that we run it later on. The
1369 * latter allows for merging opportunities and more efficient
1373 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1375 blk_mq_put_ctx(data
.ctx
);
1381 * Single hardware queue variant. This will attempt to use any per-process
1382 * plug for merging and IO deferral.
1384 static blk_qc_t
blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1386 const int is_sync
= rw_is_sync(bio_op(bio
), bio
->bi_rw
);
1387 const int is_flush_fua
= bio
->bi_rw
& (REQ_PREFLUSH
| REQ_FUA
);
1388 struct blk_plug
*plug
;
1389 unsigned int request_count
= 0;
1390 struct blk_map_ctx data
;
1394 blk_queue_bounce(q
, &bio
);
1396 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1398 return BLK_QC_T_NONE
;
1401 blk_queue_split(q
, &bio
, q
->bio_split
);
1403 if (!is_flush_fua
&& !blk_queue_nomerges(q
)) {
1404 if (blk_attempt_plug_merge(q
, bio
, &request_count
, NULL
))
1405 return BLK_QC_T_NONE
;
1407 request_count
= blk_plug_queued_count(q
);
1409 rq
= blk_mq_map_request(q
, bio
, &data
);
1411 return BLK_QC_T_NONE
;
1413 cookie
= blk_tag_to_qc_t(rq
->tag
, data
.hctx
->queue_num
);
1415 if (unlikely(is_flush_fua
)) {
1416 blk_mq_bio_to_request(rq
, bio
);
1417 blk_insert_flush(rq
);
1422 * A task plug currently exists. Since this is completely lockless,
1423 * utilize that to temporarily store requests until the task is
1424 * either done or scheduled away.
1426 plug
= current
->plug
;
1428 blk_mq_bio_to_request(rq
, bio
);
1430 trace_block_plug(q
);
1432 blk_mq_put_ctx(data
.ctx
);
1434 if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1435 blk_flush_plug_list(plug
, false);
1436 trace_block_plug(q
);
1439 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1443 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1445 * For a SYNC request, send it to the hardware immediately. For
1446 * an ASYNC request, just ensure that we run it later on. The
1447 * latter allows for merging opportunities and more efficient
1451 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1454 blk_mq_put_ctx(data
.ctx
);
1459 * Default mapping to a software queue, since we use one per CPU.
1461 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1463 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1465 EXPORT_SYMBOL(blk_mq_map_queue
);
1467 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1468 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1472 if (tags
->rqs
&& set
->ops
->exit_request
) {
1475 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1478 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1480 tags
->rqs
[i
] = NULL
;
1484 while (!list_empty(&tags
->page_list
)) {
1485 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1486 list_del_init(&page
->lru
);
1488 * Remove kmemleak object previously allocated in
1489 * blk_mq_init_rq_map().
1491 kmemleak_free(page_address(page
));
1492 __free_pages(page
, page
->private);
1497 blk_mq_free_tags(tags
);
1500 static size_t order_to_size(unsigned int order
)
1502 return (size_t)PAGE_SIZE
<< order
;
1505 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1506 unsigned int hctx_idx
)
1508 struct blk_mq_tags
*tags
;
1509 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1510 size_t rq_size
, left
;
1512 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1514 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
1518 INIT_LIST_HEAD(&tags
->page_list
);
1520 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1521 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1524 blk_mq_free_tags(tags
);
1529 * rq_size is the size of the request plus driver payload, rounded
1530 * to the cacheline size
1532 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1534 left
= rq_size
* set
->queue_depth
;
1536 for (i
= 0; i
< set
->queue_depth
; ) {
1537 int this_order
= max_order
;
1542 while (this_order
&& left
< order_to_size(this_order
- 1))
1546 page
= alloc_pages_node(set
->numa_node
,
1547 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
1553 if (order_to_size(this_order
) < rq_size
)
1560 page
->private = this_order
;
1561 list_add_tail(&page
->lru
, &tags
->page_list
);
1563 p
= page_address(page
);
1565 * Allow kmemleak to scan these pages as they contain pointers
1566 * to additional allocations like via ops->init_request().
1568 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_KERNEL
);
1569 entries_per_page
= order_to_size(this_order
) / rq_size
;
1570 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1571 left
-= to_do
* rq_size
;
1572 for (j
= 0; j
< to_do
; j
++) {
1574 if (set
->ops
->init_request
) {
1575 if (set
->ops
->init_request(set
->driver_data
,
1576 tags
->rqs
[i
], hctx_idx
, i
,
1578 tags
->rqs
[i
] = NULL
;
1590 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1594 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1599 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1601 unsigned int bpw
= 8, total
, num_maps
, i
;
1603 bitmap
->bits_per_word
= bpw
;
1605 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1606 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1612 for (i
= 0; i
< num_maps
; i
++) {
1613 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1614 total
-= bitmap
->map
[i
].depth
;
1620 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1622 struct request_queue
*q
= hctx
->queue
;
1623 struct blk_mq_ctx
*ctx
;
1627 * Move ctx entries to new CPU, if this one is going away.
1629 ctx
= __blk_mq_get_ctx(q
, cpu
);
1631 spin_lock(&ctx
->lock
);
1632 if (!list_empty(&ctx
->rq_list
)) {
1633 list_splice_init(&ctx
->rq_list
, &tmp
);
1634 blk_mq_hctx_clear_pending(hctx
, ctx
);
1636 spin_unlock(&ctx
->lock
);
1638 if (list_empty(&tmp
))
1641 ctx
= blk_mq_get_ctx(q
);
1642 spin_lock(&ctx
->lock
);
1644 while (!list_empty(&tmp
)) {
1647 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1649 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1652 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1653 blk_mq_hctx_mark_pending(hctx
, ctx
);
1655 spin_unlock(&ctx
->lock
);
1657 blk_mq_run_hw_queue(hctx
, true);
1658 blk_mq_put_ctx(ctx
);
1662 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1665 struct blk_mq_hw_ctx
*hctx
= data
;
1667 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1668 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1671 * In case of CPU online, tags may be reallocated
1672 * in blk_mq_map_swqueue() after mapping is updated.
1678 /* hctx->ctxs will be freed in queue's release handler */
1679 static void blk_mq_exit_hctx(struct request_queue
*q
,
1680 struct blk_mq_tag_set
*set
,
1681 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1683 unsigned flush_start_tag
= set
->queue_depth
;
1685 blk_mq_tag_idle(hctx
);
1687 if (set
->ops
->exit_request
)
1688 set
->ops
->exit_request(set
->driver_data
,
1689 hctx
->fq
->flush_rq
, hctx_idx
,
1690 flush_start_tag
+ hctx_idx
);
1692 if (set
->ops
->exit_hctx
)
1693 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1695 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1696 blk_free_flush_queue(hctx
->fq
);
1697 blk_mq_free_bitmap(&hctx
->ctx_map
);
1700 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1701 struct blk_mq_tag_set
*set
, int nr_queue
)
1703 struct blk_mq_hw_ctx
*hctx
;
1706 queue_for_each_hw_ctx(q
, hctx
, i
) {
1709 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1713 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1714 struct blk_mq_tag_set
*set
)
1716 struct blk_mq_hw_ctx
*hctx
;
1719 queue_for_each_hw_ctx(q
, hctx
, i
)
1720 free_cpumask_var(hctx
->cpumask
);
1723 static int blk_mq_init_hctx(struct request_queue
*q
,
1724 struct blk_mq_tag_set
*set
,
1725 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1728 unsigned flush_start_tag
= set
->queue_depth
;
1730 node
= hctx
->numa_node
;
1731 if (node
== NUMA_NO_NODE
)
1732 node
= hctx
->numa_node
= set
->numa_node
;
1734 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1735 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1736 spin_lock_init(&hctx
->lock
);
1737 INIT_LIST_HEAD(&hctx
->dispatch
);
1739 hctx
->queue_num
= hctx_idx
;
1740 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_SHARED
;
1742 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1743 blk_mq_hctx_notify
, hctx
);
1744 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1746 hctx
->tags
= set
->tags
[hctx_idx
];
1749 * Allocate space for all possible cpus to avoid allocation at
1752 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1755 goto unregister_cpu_notifier
;
1757 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1762 if (set
->ops
->init_hctx
&&
1763 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1766 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1770 if (set
->ops
->init_request
&&
1771 set
->ops
->init_request(set
->driver_data
,
1772 hctx
->fq
->flush_rq
, hctx_idx
,
1773 flush_start_tag
+ hctx_idx
, node
))
1781 if (set
->ops
->exit_hctx
)
1782 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1784 blk_mq_free_bitmap(&hctx
->ctx_map
);
1787 unregister_cpu_notifier
:
1788 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1793 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1794 unsigned int nr_hw_queues
)
1798 for_each_possible_cpu(i
) {
1799 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1800 struct blk_mq_hw_ctx
*hctx
;
1802 memset(__ctx
, 0, sizeof(*__ctx
));
1804 spin_lock_init(&__ctx
->lock
);
1805 INIT_LIST_HEAD(&__ctx
->rq_list
);
1808 /* If the cpu isn't online, the cpu is mapped to first hctx */
1812 hctx
= q
->mq_ops
->map_queue(q
, i
);
1815 * Set local node, IFF we have more than one hw queue. If
1816 * not, we remain on the home node of the device
1818 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1819 hctx
->numa_node
= local_memory_node(cpu_to_node(i
));
1823 static void blk_mq_map_swqueue(struct request_queue
*q
,
1824 const struct cpumask
*online_mask
)
1827 struct blk_mq_hw_ctx
*hctx
;
1828 struct blk_mq_ctx
*ctx
;
1829 struct blk_mq_tag_set
*set
= q
->tag_set
;
1832 * Avoid others reading imcomplete hctx->cpumask through sysfs
1834 mutex_lock(&q
->sysfs_lock
);
1836 queue_for_each_hw_ctx(q
, hctx
, i
) {
1837 cpumask_clear(hctx
->cpumask
);
1842 * Map software to hardware queues
1844 for_each_possible_cpu(i
) {
1845 /* If the cpu isn't online, the cpu is mapped to first hctx */
1846 if (!cpumask_test_cpu(i
, online_mask
))
1849 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1850 hctx
= q
->mq_ops
->map_queue(q
, i
);
1852 cpumask_set_cpu(i
, hctx
->cpumask
);
1853 ctx
->index_hw
= hctx
->nr_ctx
;
1854 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1857 mutex_unlock(&q
->sysfs_lock
);
1859 queue_for_each_hw_ctx(q
, hctx
, i
) {
1860 struct blk_mq_ctxmap
*map
= &hctx
->ctx_map
;
1863 * If no software queues are mapped to this hardware queue,
1864 * disable it and free the request entries.
1866 if (!hctx
->nr_ctx
) {
1868 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1869 set
->tags
[i
] = NULL
;
1875 /* unmapped hw queue can be remapped after CPU topo changed */
1877 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1878 hctx
->tags
= set
->tags
[i
];
1879 WARN_ON(!hctx
->tags
);
1881 cpumask_copy(hctx
->tags
->cpumask
, hctx
->cpumask
);
1883 * Set the map size to the number of mapped software queues.
1884 * This is more accurate and more efficient than looping
1885 * over all possibly mapped software queues.
1887 map
->size
= DIV_ROUND_UP(hctx
->nr_ctx
, map
->bits_per_word
);
1890 * Initialize batch roundrobin counts
1892 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1893 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1897 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
1899 struct blk_mq_hw_ctx
*hctx
;
1902 queue_for_each_hw_ctx(q
, hctx
, i
) {
1904 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1906 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1910 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
, bool shared
)
1912 struct request_queue
*q
;
1914 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1915 blk_mq_freeze_queue(q
);
1916 queue_set_hctx_shared(q
, shared
);
1917 blk_mq_unfreeze_queue(q
);
1921 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1923 struct blk_mq_tag_set
*set
= q
->tag_set
;
1925 mutex_lock(&set
->tag_list_lock
);
1926 list_del_init(&q
->tag_set_list
);
1927 if (list_is_singular(&set
->tag_list
)) {
1928 /* just transitioned to unshared */
1929 set
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1930 /* update existing queue */
1931 blk_mq_update_tag_set_depth(set
, false);
1933 mutex_unlock(&set
->tag_list_lock
);
1936 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1937 struct request_queue
*q
)
1941 mutex_lock(&set
->tag_list_lock
);
1943 /* Check to see if we're transitioning to shared (from 1 to 2 queues). */
1944 if (!list_empty(&set
->tag_list
) && !(set
->flags
& BLK_MQ_F_TAG_SHARED
)) {
1945 set
->flags
|= BLK_MQ_F_TAG_SHARED
;
1946 /* update existing queue */
1947 blk_mq_update_tag_set_depth(set
, true);
1949 if (set
->flags
& BLK_MQ_F_TAG_SHARED
)
1950 queue_set_hctx_shared(q
, true);
1951 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1953 mutex_unlock(&set
->tag_list_lock
);
1957 * It is the actual release handler for mq, but we do it from
1958 * request queue's release handler for avoiding use-after-free
1959 * and headache because q->mq_kobj shouldn't have been introduced,
1960 * but we can't group ctx/kctx kobj without it.
1962 void blk_mq_release(struct request_queue
*q
)
1964 struct blk_mq_hw_ctx
*hctx
;
1967 /* hctx kobj stays in hctx */
1968 queue_for_each_hw_ctx(q
, hctx
, i
) {
1978 kfree(q
->queue_hw_ctx
);
1980 /* ctx kobj stays in queue_ctx */
1981 free_percpu(q
->queue_ctx
);
1984 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1986 struct request_queue
*uninit_q
, *q
;
1988 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1990 return ERR_PTR(-ENOMEM
);
1992 q
= blk_mq_init_allocated_queue(set
, uninit_q
);
1994 blk_cleanup_queue(uninit_q
);
1998 EXPORT_SYMBOL(blk_mq_init_queue
);
2000 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
2001 struct request_queue
*q
)
2004 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
2006 blk_mq_sysfs_unregister(q
);
2007 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2013 node
= blk_mq_hw_queue_to_node(q
->mq_map
, i
);
2014 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
2019 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
2026 atomic_set(&hctxs
[i
]->nr_active
, 0);
2027 hctxs
[i
]->numa_node
= node
;
2028 hctxs
[i
]->queue_num
= i
;
2030 if (blk_mq_init_hctx(q
, set
, hctxs
[i
], i
)) {
2031 free_cpumask_var(hctxs
[i
]->cpumask
);
2036 blk_mq_hctx_kobj_init(hctxs
[i
]);
2038 for (j
= i
; j
< q
->nr_hw_queues
; j
++) {
2039 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
2043 blk_mq_free_rq_map(set
, hctx
->tags
, j
);
2044 set
->tags
[j
] = NULL
;
2046 blk_mq_exit_hctx(q
, set
, hctx
, j
);
2047 free_cpumask_var(hctx
->cpumask
);
2048 kobject_put(&hctx
->kobj
);
2055 q
->nr_hw_queues
= i
;
2056 blk_mq_sysfs_register(q
);
2059 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
2060 struct request_queue
*q
)
2062 /* mark the queue as mq asap */
2063 q
->mq_ops
= set
->ops
;
2065 q
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
2069 q
->queue_hw_ctx
= kzalloc_node(nr_cpu_ids
* sizeof(*(q
->queue_hw_ctx
)),
2070 GFP_KERNEL
, set
->numa_node
);
2071 if (!q
->queue_hw_ctx
)
2074 q
->mq_map
= blk_mq_make_queue_map(set
);
2078 blk_mq_realloc_hw_ctxs(set
, q
);
2079 if (!q
->nr_hw_queues
)
2082 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
2083 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
2085 q
->nr_queues
= nr_cpu_ids
;
2087 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
2089 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
2090 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
2092 q
->sg_reserved_size
= INT_MAX
;
2094 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
2095 INIT_LIST_HEAD(&q
->requeue_list
);
2096 spin_lock_init(&q
->requeue_lock
);
2098 if (q
->nr_hw_queues
> 1)
2099 blk_queue_make_request(q
, blk_mq_make_request
);
2101 blk_queue_make_request(q
, blk_sq_make_request
);
2104 * Do this after blk_queue_make_request() overrides it...
2106 q
->nr_requests
= set
->queue_depth
;
2108 if (set
->ops
->complete
)
2109 blk_queue_softirq_done(q
, set
->ops
->complete
);
2111 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
2114 mutex_lock(&all_q_mutex
);
2116 list_add_tail(&q
->all_q_node
, &all_q_list
);
2117 blk_mq_add_queue_tag_set(set
, q
);
2118 blk_mq_map_swqueue(q
, cpu_online_mask
);
2120 mutex_unlock(&all_q_mutex
);
2128 kfree(q
->queue_hw_ctx
);
2130 free_percpu(q
->queue_ctx
);
2133 return ERR_PTR(-ENOMEM
);
2135 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
2137 void blk_mq_free_queue(struct request_queue
*q
)
2139 struct blk_mq_tag_set
*set
= q
->tag_set
;
2141 mutex_lock(&all_q_mutex
);
2142 list_del_init(&q
->all_q_node
);
2143 mutex_unlock(&all_q_mutex
);
2145 blk_mq_del_queue_tag_set(q
);
2147 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
2148 blk_mq_free_hw_queues(q
, set
);
2151 /* Basically redo blk_mq_init_queue with queue frozen */
2152 static void blk_mq_queue_reinit(struct request_queue
*q
,
2153 const struct cpumask
*online_mask
)
2155 WARN_ON_ONCE(!atomic_read(&q
->mq_freeze_depth
));
2157 blk_mq_sysfs_unregister(q
);
2159 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
, online_mask
);
2162 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2163 * we should change hctx numa_node according to new topology (this
2164 * involves free and re-allocate memory, worthy doing?)
2167 blk_mq_map_swqueue(q
, online_mask
);
2169 blk_mq_sysfs_register(q
);
2172 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
2173 unsigned long action
, void *hcpu
)
2175 struct request_queue
*q
;
2176 int cpu
= (unsigned long)hcpu
;
2178 * New online cpumask which is going to be set in this hotplug event.
2179 * Declare this cpumasks as global as cpu-hotplug operation is invoked
2180 * one-by-one and dynamically allocating this could result in a failure.
2182 static struct cpumask online_new
;
2185 * Before hotadded cpu starts handling requests, new mappings must
2186 * be established. Otherwise, these requests in hw queue might
2187 * never be dispatched.
2189 * For example, there is a single hw queue (hctx) and two CPU queues
2190 * (ctx0 for CPU0, and ctx1 for CPU1).
2192 * Now CPU1 is just onlined and a request is inserted into
2193 * ctx1->rq_list and set bit0 in pending bitmap as ctx1->index_hw is
2196 * And then while running hw queue, flush_busy_ctxs() finds bit0 is
2197 * set in pending bitmap and tries to retrieve requests in
2198 * hctx->ctxs[0]->rq_list. But htx->ctxs[0] is a pointer to ctx0,
2199 * so the request in ctx1->rq_list is ignored.
2201 switch (action
& ~CPU_TASKS_FROZEN
) {
2203 case CPU_UP_CANCELED
:
2204 cpumask_copy(&online_new
, cpu_online_mask
);
2206 case CPU_UP_PREPARE
:
2207 cpumask_copy(&online_new
, cpu_online_mask
);
2208 cpumask_set_cpu(cpu
, &online_new
);
2214 mutex_lock(&all_q_mutex
);
2217 * We need to freeze and reinit all existing queues. Freezing
2218 * involves synchronous wait for an RCU grace period and doing it
2219 * one by one may take a long time. Start freezing all queues in
2220 * one swoop and then wait for the completions so that freezing can
2221 * take place in parallel.
2223 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2224 blk_mq_freeze_queue_start(q
);
2225 list_for_each_entry(q
, &all_q_list
, all_q_node
) {
2226 blk_mq_freeze_queue_wait(q
);
2229 * timeout handler can't touch hw queue during the
2232 del_timer_sync(&q
->timeout
);
2235 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2236 blk_mq_queue_reinit(q
, &online_new
);
2238 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2239 blk_mq_unfreeze_queue(q
);
2241 mutex_unlock(&all_q_mutex
);
2245 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2249 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2250 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2259 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2265 * Allocate the request maps associated with this tag_set. Note that this
2266 * may reduce the depth asked for, if memory is tight. set->queue_depth
2267 * will be updated to reflect the allocated depth.
2269 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2274 depth
= set
->queue_depth
;
2276 err
= __blk_mq_alloc_rq_maps(set
);
2280 set
->queue_depth
>>= 1;
2281 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2285 } while (set
->queue_depth
);
2287 if (!set
->queue_depth
|| err
) {
2288 pr_err("blk-mq: failed to allocate request map\n");
2292 if (depth
!= set
->queue_depth
)
2293 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2294 depth
, set
->queue_depth
);
2299 struct cpumask
*blk_mq_tags_cpumask(struct blk_mq_tags
*tags
)
2301 return tags
->cpumask
;
2303 EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask
);
2306 * Alloc a tag set to be associated with one or more request queues.
2307 * May fail with EINVAL for various error conditions. May adjust the
2308 * requested depth down, if if it too large. In that case, the set
2309 * value will be stored in set->queue_depth.
2311 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2313 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
2315 if (!set
->nr_hw_queues
)
2317 if (!set
->queue_depth
)
2319 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2322 if (!set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2325 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2326 pr_info("blk-mq: reduced tag depth to %u\n",
2328 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2332 * If a crashdump is active, then we are potentially in a very
2333 * memory constrained environment. Limit us to 1 queue and
2334 * 64 tags to prevent using too much memory.
2336 if (is_kdump_kernel()) {
2337 set
->nr_hw_queues
= 1;
2338 set
->queue_depth
= min(64U, set
->queue_depth
);
2341 * There is no use for more h/w queues than cpus.
2343 if (set
->nr_hw_queues
> nr_cpu_ids
)
2344 set
->nr_hw_queues
= nr_cpu_ids
;
2346 set
->tags
= kzalloc_node(nr_cpu_ids
* sizeof(struct blk_mq_tags
*),
2347 GFP_KERNEL
, set
->numa_node
);
2351 if (blk_mq_alloc_rq_maps(set
))
2354 mutex_init(&set
->tag_list_lock
);
2355 INIT_LIST_HEAD(&set
->tag_list
);
2363 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2365 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2369 for (i
= 0; i
< nr_cpu_ids
; i
++) {
2371 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2377 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2379 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2381 struct blk_mq_tag_set
*set
= q
->tag_set
;
2382 struct blk_mq_hw_ctx
*hctx
;
2385 if (!set
|| nr
> set
->queue_depth
)
2389 queue_for_each_hw_ctx(q
, hctx
, i
) {
2392 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2398 q
->nr_requests
= nr
;
2403 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
2405 struct request_queue
*q
;
2407 if (nr_hw_queues
> nr_cpu_ids
)
2408 nr_hw_queues
= nr_cpu_ids
;
2409 if (nr_hw_queues
< 1 || nr_hw_queues
== set
->nr_hw_queues
)
2412 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2413 blk_mq_freeze_queue(q
);
2415 set
->nr_hw_queues
= nr_hw_queues
;
2416 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2417 blk_mq_realloc_hw_ctxs(set
, q
);
2419 if (q
->nr_hw_queues
> 1)
2420 blk_queue_make_request(q
, blk_mq_make_request
);
2422 blk_queue_make_request(q
, blk_sq_make_request
);
2424 blk_mq_queue_reinit(q
, cpu_online_mask
);
2427 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2428 blk_mq_unfreeze_queue(q
);
2430 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
2432 void blk_mq_disable_hotplug(void)
2434 mutex_lock(&all_q_mutex
);
2437 void blk_mq_enable_hotplug(void)
2439 mutex_unlock(&all_q_mutex
);
2442 static int __init
blk_mq_init(void)
2446 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2450 subsys_initcall(blk_mq_init
);