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>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h>
16 #include <linux/smp.h>
17 #include <linux/llist.h>
18 #include <linux/list_sort.h>
19 #include <linux/cpu.h>
20 #include <linux/cache.h>
21 #include <linux/sched/sysctl.h>
22 #include <linux/delay.h>
23 #include <linux/crash_dump.h>
25 #include <trace/events/block.h>
27 #include <linux/blk-mq.h>
30 #include "blk-mq-tag.h"
32 static DEFINE_MUTEX(all_q_mutex
);
33 static LIST_HEAD(all_q_list
);
35 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
38 * Check if any of the ctx's have pending work in this hardware queue
40 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
44 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++)
45 if (hctx
->ctx_map
.map
[i
].word
)
51 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
52 struct blk_mq_ctx
*ctx
)
54 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
57 #define CTX_TO_BIT(hctx, ctx) \
58 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
61 * Mark this ctx as having pending work in this hardware queue
63 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
64 struct blk_mq_ctx
*ctx
)
66 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
68 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
69 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
72 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
73 struct blk_mq_ctx
*ctx
)
75 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
77 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
80 static int blk_mq_queue_enter(struct request_queue
*q
)
85 if (percpu_ref_tryget_live(&q
->mq_usage_counter
))
88 ret
= wait_event_interruptible(q
->mq_freeze_wq
,
89 !q
->mq_freeze_depth
|| blk_queue_dying(q
));
90 if (blk_queue_dying(q
))
97 static void blk_mq_queue_exit(struct request_queue
*q
)
99 percpu_ref_put(&q
->mq_usage_counter
);
102 static void blk_mq_usage_counter_release(struct percpu_ref
*ref
)
104 struct request_queue
*q
=
105 container_of(ref
, struct request_queue
, mq_usage_counter
);
107 wake_up_all(&q
->mq_freeze_wq
);
111 * Guarantee no request is in use, so we can change any data structure of
112 * the queue afterward.
114 void blk_mq_freeze_queue(struct request_queue
*q
)
118 spin_lock_irq(q
->queue_lock
);
119 freeze
= !q
->mq_freeze_depth
++;
120 spin_unlock_irq(q
->queue_lock
);
123 percpu_ref_kill(&q
->mq_usage_counter
);
124 blk_mq_run_queues(q
, false);
126 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->mq_usage_counter
));
129 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
133 spin_lock_irq(q
->queue_lock
);
134 wake
= !--q
->mq_freeze_depth
;
135 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
136 spin_unlock_irq(q
->queue_lock
);
138 percpu_ref_reinit(&q
->mq_usage_counter
);
139 wake_up_all(&q
->mq_freeze_wq
);
143 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
145 return blk_mq_has_free_tags(hctx
->tags
);
147 EXPORT_SYMBOL(blk_mq_can_queue
);
149 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
150 struct request
*rq
, unsigned int rw_flags
)
152 if (blk_queue_io_stat(q
))
153 rw_flags
|= REQ_IO_STAT
;
155 INIT_LIST_HEAD(&rq
->queuelist
);
156 /* csd/requeue_work/fifo_time is initialized before use */
159 rq
->cmd_flags
|= rw_flags
;
160 /* do not touch atomic flags, it needs atomic ops against the timer */
162 INIT_HLIST_NODE(&rq
->hash
);
163 RB_CLEAR_NODE(&rq
->rb_node
);
166 rq
->start_time
= jiffies
;
167 #ifdef CONFIG_BLK_CGROUP
169 set_start_time_ns(rq
);
170 rq
->io_start_time_ns
= 0;
172 rq
->nr_phys_segments
= 0;
173 #if defined(CONFIG_BLK_DEV_INTEGRITY)
174 rq
->nr_integrity_segments
= 0;
177 /* tag was already set */
187 INIT_LIST_HEAD(&rq
->timeout_list
);
191 rq
->end_io_data
= NULL
;
194 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
197 static struct request
*
198 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
203 tag
= blk_mq_get_tag(data
);
204 if (tag
!= BLK_MQ_TAG_FAIL
) {
205 rq
= data
->hctx
->tags
->rqs
[tag
];
207 if (blk_mq_tag_busy(data
->hctx
)) {
208 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
209 atomic_inc(&data
->hctx
->nr_active
);
213 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
220 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
223 struct blk_mq_ctx
*ctx
;
224 struct blk_mq_hw_ctx
*hctx
;
226 struct blk_mq_alloc_data alloc_data
;
229 ret
= blk_mq_queue_enter(q
);
233 ctx
= blk_mq_get_ctx(q
);
234 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
235 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
236 reserved
, ctx
, hctx
);
238 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
239 if (!rq
&& (gfp
& __GFP_WAIT
)) {
240 __blk_mq_run_hw_queue(hctx
);
243 ctx
= blk_mq_get_ctx(q
);
244 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
245 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
247 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
248 ctx
= alloc_data
.ctx
;
252 return ERR_PTR(-EWOULDBLOCK
);
255 EXPORT_SYMBOL(blk_mq_alloc_request
);
257 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
258 struct blk_mq_ctx
*ctx
, struct request
*rq
)
260 const int tag
= rq
->tag
;
261 struct request_queue
*q
= rq
->q
;
263 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
264 atomic_dec(&hctx
->nr_active
);
267 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
268 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
269 blk_mq_queue_exit(q
);
272 void blk_mq_free_request(struct request
*rq
)
274 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
275 struct blk_mq_hw_ctx
*hctx
;
276 struct request_queue
*q
= rq
->q
;
278 ctx
->rq_completed
[rq_is_sync(rq
)]++;
280 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
281 __blk_mq_free_request(hctx
, ctx
, rq
);
285 * Clone all relevant state from a request that has been put on hold in
286 * the flush state machine into the preallocated flush request that hangs
287 * off the request queue.
289 * For a driver the flush request should be invisible, that's why we are
290 * impersonating the original request here.
292 void blk_mq_clone_flush_request(struct request
*flush_rq
,
293 struct request
*orig_rq
)
295 struct blk_mq_hw_ctx
*hctx
=
296 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
298 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
299 flush_rq
->tag
= orig_rq
->tag
;
300 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
304 inline void __blk_mq_end_request(struct request
*rq
, int error
)
306 blk_account_io_done(rq
);
309 rq
->end_io(rq
, error
);
311 if (unlikely(blk_bidi_rq(rq
)))
312 blk_mq_free_request(rq
->next_rq
);
313 blk_mq_free_request(rq
);
316 EXPORT_SYMBOL(__blk_mq_end_request
);
318 void blk_mq_end_request(struct request
*rq
, int error
)
320 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
322 __blk_mq_end_request(rq
, error
);
324 EXPORT_SYMBOL(blk_mq_end_request
);
326 static void __blk_mq_complete_request_remote(void *data
)
328 struct request
*rq
= data
;
330 rq
->q
->softirq_done_fn(rq
);
333 static void blk_mq_ipi_complete_request(struct request
*rq
)
335 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
339 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
340 rq
->q
->softirq_done_fn(rq
);
345 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
346 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
348 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
349 rq
->csd
.func
= __blk_mq_complete_request_remote
;
352 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
354 rq
->q
->softirq_done_fn(rq
);
359 void __blk_mq_complete_request(struct request
*rq
)
361 struct request_queue
*q
= rq
->q
;
363 if (!q
->softirq_done_fn
)
364 blk_mq_end_request(rq
, rq
->errors
);
366 blk_mq_ipi_complete_request(rq
);
370 * blk_mq_complete_request - end I/O on a request
371 * @rq: the request being processed
374 * Ends all I/O on a request. It does not handle partial completions.
375 * The actual completion happens out-of-order, through a IPI handler.
377 void blk_mq_complete_request(struct request
*rq
)
379 struct request_queue
*q
= rq
->q
;
381 if (unlikely(blk_should_fake_timeout(q
)))
383 if (!blk_mark_rq_complete(rq
))
384 __blk_mq_complete_request(rq
);
386 EXPORT_SYMBOL(blk_mq_complete_request
);
388 void blk_mq_start_request(struct request
*rq
)
390 struct request_queue
*q
= rq
->q
;
392 trace_block_rq_issue(q
, rq
);
394 rq
->resid_len
= blk_rq_bytes(rq
);
395 if (unlikely(blk_bidi_rq(rq
)))
396 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
401 * Ensure that ->deadline is visible before set the started
402 * flag and clear the completed flag.
404 smp_mb__before_atomic();
407 * Mark us as started and clear complete. Complete might have been
408 * set if requeue raced with timeout, which then marked it as
409 * complete. So be sure to clear complete again when we start
410 * the request, otherwise we'll ignore the completion event.
412 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
413 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
414 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
415 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
417 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
419 * Make sure space for the drain appears. We know we can do
420 * this because max_hw_segments has been adjusted to be one
421 * fewer than the device can handle.
423 rq
->nr_phys_segments
++;
426 EXPORT_SYMBOL(blk_mq_start_request
);
428 static void __blk_mq_requeue_request(struct request
*rq
)
430 struct request_queue
*q
= rq
->q
;
432 trace_block_rq_requeue(q
, rq
);
434 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
435 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
436 rq
->nr_phys_segments
--;
440 void blk_mq_requeue_request(struct request
*rq
)
442 __blk_mq_requeue_request(rq
);
444 BUG_ON(blk_queued_rq(rq
));
445 blk_mq_add_to_requeue_list(rq
, true);
447 EXPORT_SYMBOL(blk_mq_requeue_request
);
449 static void blk_mq_requeue_work(struct work_struct
*work
)
451 struct request_queue
*q
=
452 container_of(work
, struct request_queue
, requeue_work
);
454 struct request
*rq
, *next
;
457 spin_lock_irqsave(&q
->requeue_lock
, flags
);
458 list_splice_init(&q
->requeue_list
, &rq_list
);
459 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
461 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
462 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
465 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
466 list_del_init(&rq
->queuelist
);
467 blk_mq_insert_request(rq
, true, false, false);
470 while (!list_empty(&rq_list
)) {
471 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
472 list_del_init(&rq
->queuelist
);
473 blk_mq_insert_request(rq
, false, false, false);
477 * Use the start variant of queue running here, so that running
478 * the requeue work will kick stopped queues.
480 blk_mq_start_hw_queues(q
);
483 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
485 struct request_queue
*q
= rq
->q
;
489 * We abuse this flag that is otherwise used by the I/O scheduler to
490 * request head insertation from the workqueue.
492 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
494 spin_lock_irqsave(&q
->requeue_lock
, flags
);
496 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
497 list_add(&rq
->queuelist
, &q
->requeue_list
);
499 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
501 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
503 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
505 void blk_mq_kick_requeue_list(struct request_queue
*q
)
507 kblockd_schedule_work(&q
->requeue_work
);
509 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
511 static inline bool is_flush_request(struct request
*rq
, unsigned int tag
)
513 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
514 rq
->q
->flush_rq
->tag
== tag
);
517 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
519 struct request
*rq
= tags
->rqs
[tag
];
521 if (!is_flush_request(rq
, tag
))
524 return rq
->q
->flush_rq
;
526 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
528 struct blk_mq_timeout_data
{
530 unsigned int next_set
;
533 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
535 struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
536 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
539 * We know that complete is set at this point. If STARTED isn't set
540 * anymore, then the request isn't active and the "timeout" should
541 * just be ignored. This can happen due to the bitflag ordering.
542 * Timeout first checks if STARTED is set, and if it is, assumes
543 * the request is active. But if we race with completion, then
544 * we both flags will get cleared. So check here again, and ignore
545 * a timeout event with a request that isn't active.
547 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
551 ret
= ops
->timeout(req
, reserved
);
555 __blk_mq_complete_request(req
);
557 case BLK_EH_RESET_TIMER
:
559 blk_clear_rq_complete(req
);
561 case BLK_EH_NOT_HANDLED
:
564 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
569 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
570 struct request
*rq
, void *priv
, bool reserved
)
572 struct blk_mq_timeout_data
*data
= priv
;
574 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
577 if (time_after_eq(jiffies
, rq
->deadline
)) {
578 if (!blk_mark_rq_complete(rq
))
579 blk_mq_rq_timed_out(rq
, reserved
);
580 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
581 data
->next
= rq
->deadline
;
586 static void blk_mq_rq_timer(unsigned long priv
)
588 struct request_queue
*q
= (struct request_queue
*)priv
;
589 struct blk_mq_timeout_data data
= {
593 struct blk_mq_hw_ctx
*hctx
;
596 queue_for_each_hw_ctx(q
, hctx
, i
) {
598 * If not software queues are currently mapped to this
599 * hardware queue, there's nothing to check
601 if (!hctx
->nr_ctx
|| !hctx
->tags
)
604 blk_mq_tag_busy_iter(hctx
, blk_mq_check_expired
, &data
);
608 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
609 mod_timer(&q
->timeout
, data
.next
);
611 queue_for_each_hw_ctx(q
, hctx
, i
)
612 blk_mq_tag_idle(hctx
);
617 * Reverse check our software queue for entries that we could potentially
618 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
619 * too much time checking for merges.
621 static bool blk_mq_attempt_merge(struct request_queue
*q
,
622 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
627 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
633 if (!blk_rq_merge_ok(rq
, bio
))
636 el_ret
= blk_try_merge(rq
, bio
);
637 if (el_ret
== ELEVATOR_BACK_MERGE
) {
638 if (bio_attempt_back_merge(q
, rq
, bio
)) {
643 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
644 if (bio_attempt_front_merge(q
, rq
, bio
)) {
656 * Process software queues that have been marked busy, splicing them
657 * to the for-dispatch
659 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
661 struct blk_mq_ctx
*ctx
;
664 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
665 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
666 unsigned int off
, bit
;
672 off
= i
* hctx
->ctx_map
.bits_per_word
;
674 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
675 if (bit
>= bm
->depth
)
678 ctx
= hctx
->ctxs
[bit
+ off
];
679 clear_bit(bit
, &bm
->word
);
680 spin_lock(&ctx
->lock
);
681 list_splice_tail_init(&ctx
->rq_list
, list
);
682 spin_unlock(&ctx
->lock
);
690 * Run this hardware queue, pulling any software queues mapped to it in.
691 * Note that this function currently has various problems around ordering
692 * of IO. In particular, we'd like FIFO behaviour on handling existing
693 * items on the hctx->dispatch list. Ignore that for now.
695 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
697 struct request_queue
*q
= hctx
->queue
;
702 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
704 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
710 * Touch any software queue that has pending entries.
712 flush_busy_ctxs(hctx
, &rq_list
);
715 * If we have previous entries on our dispatch list, grab them
716 * and stuff them at the front for more fair dispatch.
718 if (!list_empty_careful(&hctx
->dispatch
)) {
719 spin_lock(&hctx
->lock
);
720 if (!list_empty(&hctx
->dispatch
))
721 list_splice_init(&hctx
->dispatch
, &rq_list
);
722 spin_unlock(&hctx
->lock
);
726 * Now process all the entries, sending them to the driver.
729 while (!list_empty(&rq_list
)) {
732 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
733 list_del_init(&rq
->queuelist
);
735 ret
= q
->mq_ops
->queue_rq(hctx
, rq
, list_empty(&rq_list
));
737 case BLK_MQ_RQ_QUEUE_OK
:
740 case BLK_MQ_RQ_QUEUE_BUSY
:
741 list_add(&rq
->queuelist
, &rq_list
);
742 __blk_mq_requeue_request(rq
);
745 pr_err("blk-mq: bad return on queue: %d\n", ret
);
746 case BLK_MQ_RQ_QUEUE_ERROR
:
748 blk_mq_end_request(rq
, rq
->errors
);
752 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
757 hctx
->dispatched
[0]++;
758 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
759 hctx
->dispatched
[ilog2(queued
) + 1]++;
762 * Any items that need requeuing? Stuff them into hctx->dispatch,
763 * that is where we will continue on next queue run.
765 if (!list_empty(&rq_list
)) {
766 spin_lock(&hctx
->lock
);
767 list_splice(&rq_list
, &hctx
->dispatch
);
768 spin_unlock(&hctx
->lock
);
773 * It'd be great if the workqueue API had a way to pass
774 * in a mask and had some smarts for more clever placement.
775 * For now we just round-robin here, switching for every
776 * BLK_MQ_CPU_WORK_BATCH queued items.
778 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
780 int cpu
= hctx
->next_cpu
;
782 if (--hctx
->next_cpu_batch
<= 0) {
785 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
786 if (next_cpu
>= nr_cpu_ids
)
787 next_cpu
= cpumask_first(hctx
->cpumask
);
789 hctx
->next_cpu
= next_cpu
;
790 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
796 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
798 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
801 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
802 __blk_mq_run_hw_queue(hctx
);
803 else if (hctx
->queue
->nr_hw_queues
== 1)
804 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
808 cpu
= blk_mq_hctx_next_cpu(hctx
);
809 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
813 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
815 struct blk_mq_hw_ctx
*hctx
;
818 queue_for_each_hw_ctx(q
, hctx
, i
) {
819 if ((!blk_mq_hctx_has_pending(hctx
) &&
820 list_empty_careful(&hctx
->dispatch
)) ||
821 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
825 blk_mq_run_hw_queue(hctx
, async
);
829 EXPORT_SYMBOL(blk_mq_run_queues
);
831 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
833 cancel_delayed_work(&hctx
->run_work
);
834 cancel_delayed_work(&hctx
->delay_work
);
835 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
837 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
839 void blk_mq_stop_hw_queues(struct request_queue
*q
)
841 struct blk_mq_hw_ctx
*hctx
;
844 queue_for_each_hw_ctx(q
, hctx
, i
)
845 blk_mq_stop_hw_queue(hctx
);
847 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
849 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
851 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
854 blk_mq_run_hw_queue(hctx
, false);
857 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
859 void blk_mq_start_hw_queues(struct request_queue
*q
)
861 struct blk_mq_hw_ctx
*hctx
;
864 queue_for_each_hw_ctx(q
, hctx
, i
)
865 blk_mq_start_hw_queue(hctx
);
867 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
870 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
872 struct blk_mq_hw_ctx
*hctx
;
875 queue_for_each_hw_ctx(q
, hctx
, i
) {
876 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
879 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
881 blk_mq_run_hw_queue(hctx
, async
);
885 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
887 static void blk_mq_run_work_fn(struct work_struct
*work
)
889 struct blk_mq_hw_ctx
*hctx
;
891 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
893 __blk_mq_run_hw_queue(hctx
);
896 static void blk_mq_delay_work_fn(struct work_struct
*work
)
898 struct blk_mq_hw_ctx
*hctx
;
900 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
902 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
903 __blk_mq_run_hw_queue(hctx
);
906 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
908 unsigned long tmo
= msecs_to_jiffies(msecs
);
910 if (hctx
->queue
->nr_hw_queues
== 1)
911 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
915 cpu
= blk_mq_hctx_next_cpu(hctx
);
916 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
919 EXPORT_SYMBOL(blk_mq_delay_queue
);
921 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
922 struct request
*rq
, bool at_head
)
924 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
926 trace_block_rq_insert(hctx
->queue
, rq
);
929 list_add(&rq
->queuelist
, &ctx
->rq_list
);
931 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
933 blk_mq_hctx_mark_pending(hctx
, ctx
);
936 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
939 struct request_queue
*q
= rq
->q
;
940 struct blk_mq_hw_ctx
*hctx
;
941 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
943 current_ctx
= blk_mq_get_ctx(q
);
944 if (!cpu_online(ctx
->cpu
))
945 rq
->mq_ctx
= ctx
= current_ctx
;
947 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
949 spin_lock(&ctx
->lock
);
950 __blk_mq_insert_request(hctx
, rq
, at_head
);
951 spin_unlock(&ctx
->lock
);
954 blk_mq_run_hw_queue(hctx
, async
);
956 blk_mq_put_ctx(current_ctx
);
959 static void blk_mq_insert_requests(struct request_queue
*q
,
960 struct blk_mq_ctx
*ctx
,
961 struct list_head
*list
,
966 struct blk_mq_hw_ctx
*hctx
;
967 struct blk_mq_ctx
*current_ctx
;
969 trace_block_unplug(q
, depth
, !from_schedule
);
971 current_ctx
= blk_mq_get_ctx(q
);
973 if (!cpu_online(ctx
->cpu
))
975 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
978 * preemption doesn't flush plug list, so it's possible ctx->cpu is
981 spin_lock(&ctx
->lock
);
982 while (!list_empty(list
)) {
985 rq
= list_first_entry(list
, struct request
, queuelist
);
986 list_del_init(&rq
->queuelist
);
988 __blk_mq_insert_request(hctx
, rq
, false);
990 spin_unlock(&ctx
->lock
);
992 blk_mq_run_hw_queue(hctx
, from_schedule
);
993 blk_mq_put_ctx(current_ctx
);
996 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
998 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
999 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1001 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1002 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1003 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1006 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1008 struct blk_mq_ctx
*this_ctx
;
1009 struct request_queue
*this_q
;
1012 LIST_HEAD(ctx_list
);
1015 list_splice_init(&plug
->mq_list
, &list
);
1017 list_sort(NULL
, &list
, plug_ctx_cmp
);
1023 while (!list_empty(&list
)) {
1024 rq
= list_entry_rq(list
.next
);
1025 list_del_init(&rq
->queuelist
);
1027 if (rq
->mq_ctx
!= this_ctx
) {
1029 blk_mq_insert_requests(this_q
, this_ctx
,
1034 this_ctx
= rq
->mq_ctx
;
1040 list_add_tail(&rq
->queuelist
, &ctx_list
);
1044 * If 'this_ctx' is set, we know we have entries to complete
1045 * on 'ctx_list'. Do those.
1048 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1053 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1055 init_request_from_bio(rq
, bio
);
1057 if (blk_do_io_stat(rq
))
1058 blk_account_io_start(rq
, 1);
1061 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1063 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1064 !blk_queue_nomerges(hctx
->queue
);
1067 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1068 struct blk_mq_ctx
*ctx
,
1069 struct request
*rq
, struct bio
*bio
)
1071 if (!hctx_allow_merges(hctx
)) {
1072 blk_mq_bio_to_request(rq
, bio
);
1073 spin_lock(&ctx
->lock
);
1075 __blk_mq_insert_request(hctx
, rq
, false);
1076 spin_unlock(&ctx
->lock
);
1079 struct request_queue
*q
= hctx
->queue
;
1081 spin_lock(&ctx
->lock
);
1082 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1083 blk_mq_bio_to_request(rq
, bio
);
1087 spin_unlock(&ctx
->lock
);
1088 __blk_mq_free_request(hctx
, ctx
, rq
);
1093 struct blk_map_ctx
{
1094 struct blk_mq_hw_ctx
*hctx
;
1095 struct blk_mq_ctx
*ctx
;
1098 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1100 struct blk_map_ctx
*data
)
1102 struct blk_mq_hw_ctx
*hctx
;
1103 struct blk_mq_ctx
*ctx
;
1105 int rw
= bio_data_dir(bio
);
1106 struct blk_mq_alloc_data alloc_data
;
1108 if (unlikely(blk_mq_queue_enter(q
))) {
1109 bio_endio(bio
, -EIO
);
1113 ctx
= blk_mq_get_ctx(q
);
1114 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1116 if (rw_is_sync(bio
->bi_rw
))
1119 trace_block_getrq(q
, bio
, rw
);
1120 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1122 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1123 if (unlikely(!rq
)) {
1124 __blk_mq_run_hw_queue(hctx
);
1125 blk_mq_put_ctx(ctx
);
1126 trace_block_sleeprq(q
, bio
, rw
);
1128 ctx
= blk_mq_get_ctx(q
);
1129 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1130 blk_mq_set_alloc_data(&alloc_data
, q
,
1131 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1132 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1133 ctx
= alloc_data
.ctx
;
1134 hctx
= alloc_data
.hctx
;
1144 * Multiple hardware queue variant. This will not use per-process plugs,
1145 * but will attempt to bypass the hctx queueing if we can go straight to
1146 * hardware for SYNC IO.
1148 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1150 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1151 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1152 struct blk_map_ctx data
;
1155 blk_queue_bounce(q
, &bio
);
1157 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1158 bio_endio(bio
, -EIO
);
1162 rq
= blk_mq_map_request(q
, bio
, &data
);
1166 if (unlikely(is_flush_fua
)) {
1167 blk_mq_bio_to_request(rq
, bio
);
1168 blk_insert_flush(rq
);
1175 blk_mq_bio_to_request(rq
, bio
);
1178 * For OK queue, we are done. For error, kill it. Any other
1179 * error (busy), just add it to our list as we previously
1182 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
, true);
1183 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1186 __blk_mq_requeue_request(rq
);
1188 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1190 blk_mq_end_request(rq
, rq
->errors
);
1196 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1198 * For a SYNC request, send it to the hardware immediately. For
1199 * an ASYNC request, just ensure that we run it later on. The
1200 * latter allows for merging opportunities and more efficient
1204 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1207 blk_mq_put_ctx(data
.ctx
);
1211 * Single hardware queue variant. This will attempt to use any per-process
1212 * plug for merging and IO deferral.
1214 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1216 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1217 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1218 unsigned int use_plug
, request_count
= 0;
1219 struct blk_map_ctx data
;
1223 * If we have multiple hardware queues, just go directly to
1224 * one of those for sync IO.
1226 use_plug
= !is_flush_fua
&& !is_sync
;
1228 blk_queue_bounce(q
, &bio
);
1230 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1231 bio_endio(bio
, -EIO
);
1235 if (use_plug
&& !blk_queue_nomerges(q
) &&
1236 blk_attempt_plug_merge(q
, bio
, &request_count
))
1239 rq
= blk_mq_map_request(q
, bio
, &data
);
1243 if (unlikely(is_flush_fua
)) {
1244 blk_mq_bio_to_request(rq
, bio
);
1245 blk_insert_flush(rq
);
1250 * A task plug currently exists. Since this is completely lockless,
1251 * utilize that to temporarily store requests until the task is
1252 * either done or scheduled away.
1255 struct blk_plug
*plug
= current
->plug
;
1258 blk_mq_bio_to_request(rq
, bio
);
1259 if (list_empty(&plug
->mq_list
))
1260 trace_block_plug(q
);
1261 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1262 blk_flush_plug_list(plug
, false);
1263 trace_block_plug(q
);
1265 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1266 blk_mq_put_ctx(data
.ctx
);
1271 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1273 * For a SYNC request, send it to the hardware immediately. For
1274 * an ASYNC request, just ensure that we run it later on. The
1275 * latter allows for merging opportunities and more efficient
1279 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1282 blk_mq_put_ctx(data
.ctx
);
1286 * Default mapping to a software queue, since we use one per CPU.
1288 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1290 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1292 EXPORT_SYMBOL(blk_mq_map_queue
);
1294 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1295 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1299 if (tags
->rqs
&& set
->ops
->exit_request
) {
1302 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1305 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1307 tags
->rqs
[i
] = NULL
;
1311 while (!list_empty(&tags
->page_list
)) {
1312 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1313 list_del_init(&page
->lru
);
1314 __free_pages(page
, page
->private);
1319 blk_mq_free_tags(tags
);
1322 static size_t order_to_size(unsigned int order
)
1324 return (size_t)PAGE_SIZE
<< order
;
1327 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1328 unsigned int hctx_idx
)
1330 struct blk_mq_tags
*tags
;
1331 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1332 size_t rq_size
, left
;
1334 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1339 INIT_LIST_HEAD(&tags
->page_list
);
1341 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1342 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1345 blk_mq_free_tags(tags
);
1350 * rq_size is the size of the request plus driver payload, rounded
1351 * to the cacheline size
1353 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1355 left
= rq_size
* set
->queue_depth
;
1357 for (i
= 0; i
< set
->queue_depth
; ) {
1358 int this_order
= max_order
;
1363 while (left
< order_to_size(this_order
- 1) && this_order
)
1367 page
= alloc_pages_node(set
->numa_node
,
1368 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1374 if (order_to_size(this_order
) < rq_size
)
1381 page
->private = this_order
;
1382 list_add_tail(&page
->lru
, &tags
->page_list
);
1384 p
= page_address(page
);
1385 entries_per_page
= order_to_size(this_order
) / rq_size
;
1386 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1387 left
-= to_do
* rq_size
;
1388 for (j
= 0; j
< to_do
; j
++) {
1390 tags
->rqs
[i
]->atomic_flags
= 0;
1391 tags
->rqs
[i
]->cmd_flags
= 0;
1392 if (set
->ops
->init_request
) {
1393 if (set
->ops
->init_request(set
->driver_data
,
1394 tags
->rqs
[i
], hctx_idx
, i
,
1396 tags
->rqs
[i
] = NULL
;
1409 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1413 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1418 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1420 unsigned int bpw
= 8, total
, num_maps
, i
;
1422 bitmap
->bits_per_word
= bpw
;
1424 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1425 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1430 bitmap
->map_size
= num_maps
;
1433 for (i
= 0; i
< num_maps
; i
++) {
1434 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1435 total
-= bitmap
->map
[i
].depth
;
1441 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1443 struct request_queue
*q
= hctx
->queue
;
1444 struct blk_mq_ctx
*ctx
;
1448 * Move ctx entries to new CPU, if this one is going away.
1450 ctx
= __blk_mq_get_ctx(q
, cpu
);
1452 spin_lock(&ctx
->lock
);
1453 if (!list_empty(&ctx
->rq_list
)) {
1454 list_splice_init(&ctx
->rq_list
, &tmp
);
1455 blk_mq_hctx_clear_pending(hctx
, ctx
);
1457 spin_unlock(&ctx
->lock
);
1459 if (list_empty(&tmp
))
1462 ctx
= blk_mq_get_ctx(q
);
1463 spin_lock(&ctx
->lock
);
1465 while (!list_empty(&tmp
)) {
1468 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1470 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1473 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1474 blk_mq_hctx_mark_pending(hctx
, ctx
);
1476 spin_unlock(&ctx
->lock
);
1478 blk_mq_run_hw_queue(hctx
, true);
1479 blk_mq_put_ctx(ctx
);
1483 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1485 struct request_queue
*q
= hctx
->queue
;
1486 struct blk_mq_tag_set
*set
= q
->tag_set
;
1488 if (set
->tags
[hctx
->queue_num
])
1491 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1492 if (!set
->tags
[hctx
->queue_num
])
1495 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1499 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1502 struct blk_mq_hw_ctx
*hctx
= data
;
1504 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1505 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1506 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1507 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1512 static void blk_mq_exit_hctx(struct request_queue
*q
,
1513 struct blk_mq_tag_set
*set
,
1514 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1516 blk_mq_tag_idle(hctx
);
1518 if (set
->ops
->exit_hctx
)
1519 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1521 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1523 blk_mq_free_bitmap(&hctx
->ctx_map
);
1526 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1527 struct blk_mq_tag_set
*set
, int nr_queue
)
1529 struct blk_mq_hw_ctx
*hctx
;
1532 queue_for_each_hw_ctx(q
, hctx
, i
) {
1535 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1539 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1540 struct blk_mq_tag_set
*set
)
1542 struct blk_mq_hw_ctx
*hctx
;
1545 queue_for_each_hw_ctx(q
, hctx
, i
) {
1546 free_cpumask_var(hctx
->cpumask
);
1551 static int blk_mq_init_hctx(struct request_queue
*q
,
1552 struct blk_mq_tag_set
*set
,
1553 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1557 node
= hctx
->numa_node
;
1558 if (node
== NUMA_NO_NODE
)
1559 node
= hctx
->numa_node
= set
->numa_node
;
1561 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1562 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1563 spin_lock_init(&hctx
->lock
);
1564 INIT_LIST_HEAD(&hctx
->dispatch
);
1566 hctx
->queue_num
= hctx_idx
;
1567 hctx
->flags
= set
->flags
;
1568 hctx
->cmd_size
= set
->cmd_size
;
1570 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1571 blk_mq_hctx_notify
, hctx
);
1572 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1574 hctx
->tags
= set
->tags
[hctx_idx
];
1577 * Allocate space for all possible cpus to avoid allocation at
1580 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1583 goto unregister_cpu_notifier
;
1585 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1590 if (set
->ops
->init_hctx
&&
1591 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1597 blk_mq_free_bitmap(&hctx
->ctx_map
);
1600 unregister_cpu_notifier
:
1601 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1606 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1607 struct blk_mq_tag_set
*set
)
1609 struct blk_mq_hw_ctx
*hctx
;
1613 * Initialize hardware queues
1615 queue_for_each_hw_ctx(q
, hctx
, i
) {
1616 if (blk_mq_init_hctx(q
, set
, hctx
, i
))
1620 if (i
== q
->nr_hw_queues
)
1626 blk_mq_exit_hw_queues(q
, set
, i
);
1631 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1632 unsigned int nr_hw_queues
)
1636 for_each_possible_cpu(i
) {
1637 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1638 struct blk_mq_hw_ctx
*hctx
;
1640 memset(__ctx
, 0, sizeof(*__ctx
));
1642 spin_lock_init(&__ctx
->lock
);
1643 INIT_LIST_HEAD(&__ctx
->rq_list
);
1646 /* If the cpu isn't online, the cpu is mapped to first hctx */
1650 hctx
= q
->mq_ops
->map_queue(q
, i
);
1651 cpumask_set_cpu(i
, hctx
->cpumask
);
1655 * Set local node, IFF we have more than one hw queue. If
1656 * not, we remain on the home node of the device
1658 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1659 hctx
->numa_node
= cpu_to_node(i
);
1663 static void blk_mq_map_swqueue(struct request_queue
*q
)
1666 struct blk_mq_hw_ctx
*hctx
;
1667 struct blk_mq_ctx
*ctx
;
1669 queue_for_each_hw_ctx(q
, hctx
, i
) {
1670 cpumask_clear(hctx
->cpumask
);
1675 * Map software to hardware queues
1677 queue_for_each_ctx(q
, ctx
, i
) {
1678 /* If the cpu isn't online, the cpu is mapped to first hctx */
1682 hctx
= q
->mq_ops
->map_queue(q
, i
);
1683 cpumask_set_cpu(i
, hctx
->cpumask
);
1684 ctx
->index_hw
= hctx
->nr_ctx
;
1685 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1688 queue_for_each_hw_ctx(q
, hctx
, i
) {
1690 * If no software queues are mapped to this hardware queue,
1691 * disable it and free the request entries.
1693 if (!hctx
->nr_ctx
) {
1694 struct blk_mq_tag_set
*set
= q
->tag_set
;
1697 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1698 set
->tags
[i
] = NULL
;
1705 * Initialize batch roundrobin counts
1707 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1708 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1712 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1714 struct blk_mq_hw_ctx
*hctx
;
1715 struct request_queue
*q
;
1719 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1724 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1725 blk_mq_freeze_queue(q
);
1727 queue_for_each_hw_ctx(q
, hctx
, i
) {
1729 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1731 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1733 blk_mq_unfreeze_queue(q
);
1737 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1739 struct blk_mq_tag_set
*set
= q
->tag_set
;
1741 mutex_lock(&set
->tag_list_lock
);
1742 list_del_init(&q
->tag_set_list
);
1743 blk_mq_update_tag_set_depth(set
);
1744 mutex_unlock(&set
->tag_list_lock
);
1747 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1748 struct request_queue
*q
)
1752 mutex_lock(&set
->tag_list_lock
);
1753 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1754 blk_mq_update_tag_set_depth(set
);
1755 mutex_unlock(&set
->tag_list_lock
);
1758 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1760 struct blk_mq_hw_ctx
**hctxs
;
1761 struct blk_mq_ctx __percpu
*ctx
;
1762 struct request_queue
*q
;
1766 ctx
= alloc_percpu(struct blk_mq_ctx
);
1768 return ERR_PTR(-ENOMEM
);
1771 * If a crashdump is active, then we are potentially in a very
1772 * memory constrained environment. Limit us to 1 queue and
1773 * 64 tags to prevent using too much memory.
1775 if (is_kdump_kernel()) {
1776 set
->nr_hw_queues
= 1;
1777 set
->queue_depth
= min(64U, set
->queue_depth
);
1780 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1786 map
= blk_mq_make_queue_map(set
);
1790 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1791 int node
= blk_mq_hw_queue_to_node(map
, i
);
1793 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1798 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1801 atomic_set(&hctxs
[i
]->nr_active
, 0);
1802 hctxs
[i
]->numa_node
= node
;
1803 hctxs
[i
]->queue_num
= i
;
1806 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1810 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
))
1813 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1814 blk_queue_rq_timeout(q
, 30000);
1816 q
->nr_queues
= nr_cpu_ids
;
1817 q
->nr_hw_queues
= set
->nr_hw_queues
;
1821 q
->queue_hw_ctx
= hctxs
;
1823 q
->mq_ops
= set
->ops
;
1824 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1826 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1827 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1829 q
->sg_reserved_size
= INT_MAX
;
1831 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1832 INIT_LIST_HEAD(&q
->requeue_list
);
1833 spin_lock_init(&q
->requeue_lock
);
1835 if (q
->nr_hw_queues
> 1)
1836 blk_queue_make_request(q
, blk_mq_make_request
);
1838 blk_queue_make_request(q
, blk_sq_make_request
);
1841 blk_queue_rq_timeout(q
, set
->timeout
);
1844 * Do this after blk_queue_make_request() overrides it...
1846 q
->nr_requests
= set
->queue_depth
;
1848 if (set
->ops
->complete
)
1849 blk_queue_softirq_done(q
, set
->ops
->complete
);
1851 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1853 if (blk_mq_init_hw_queues(q
, set
))
1856 mutex_lock(&all_q_mutex
);
1857 list_add_tail(&q
->all_q_node
, &all_q_list
);
1858 mutex_unlock(&all_q_mutex
);
1860 blk_mq_add_queue_tag_set(set
, q
);
1862 if (blk_init_flush(q
))
1865 blk_mq_map_swqueue(q
);
1870 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1872 blk_cleanup_queue(q
);
1875 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1878 free_cpumask_var(hctxs
[i
]->cpumask
);
1885 return ERR_PTR(-ENOMEM
);
1887 EXPORT_SYMBOL(blk_mq_init_queue
);
1889 void blk_mq_free_queue(struct request_queue
*q
)
1891 struct blk_mq_tag_set
*set
= q
->tag_set
;
1893 blk_mq_del_queue_tag_set(q
);
1895 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1896 blk_mq_free_hw_queues(q
, set
);
1898 percpu_ref_exit(&q
->mq_usage_counter
);
1900 free_percpu(q
->queue_ctx
);
1901 kfree(q
->queue_hw_ctx
);
1904 q
->queue_ctx
= NULL
;
1905 q
->queue_hw_ctx
= NULL
;
1908 mutex_lock(&all_q_mutex
);
1909 list_del_init(&q
->all_q_node
);
1910 mutex_unlock(&all_q_mutex
);
1913 /* Basically redo blk_mq_init_queue with queue frozen */
1914 static void blk_mq_queue_reinit(struct request_queue
*q
)
1916 blk_mq_freeze_queue(q
);
1918 blk_mq_sysfs_unregister(q
);
1920 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1923 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1924 * we should change hctx numa_node according to new topology (this
1925 * involves free and re-allocate memory, worthy doing?)
1928 blk_mq_map_swqueue(q
);
1930 blk_mq_sysfs_register(q
);
1932 blk_mq_unfreeze_queue(q
);
1935 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1936 unsigned long action
, void *hcpu
)
1938 struct request_queue
*q
;
1941 * Before new mappings are established, hotadded cpu might already
1942 * start handling requests. This doesn't break anything as we map
1943 * offline CPUs to first hardware queue. We will re-init the queue
1944 * below to get optimal settings.
1946 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1947 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1950 mutex_lock(&all_q_mutex
);
1951 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1952 blk_mq_queue_reinit(q
);
1953 mutex_unlock(&all_q_mutex
);
1957 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1961 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1962 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1971 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1977 * Allocate the request maps associated with this tag_set. Note that this
1978 * may reduce the depth asked for, if memory is tight. set->queue_depth
1979 * will be updated to reflect the allocated depth.
1981 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1986 depth
= set
->queue_depth
;
1988 err
= __blk_mq_alloc_rq_maps(set
);
1992 set
->queue_depth
>>= 1;
1993 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
1997 } while (set
->queue_depth
);
1999 if (!set
->queue_depth
|| err
) {
2000 pr_err("blk-mq: failed to allocate request map\n");
2004 if (depth
!= set
->queue_depth
)
2005 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2006 depth
, set
->queue_depth
);
2012 * Alloc a tag set to be associated with one or more request queues.
2013 * May fail with EINVAL for various error conditions. May adjust the
2014 * requested depth down, if if it too large. In that case, the set
2015 * value will be stored in set->queue_depth.
2017 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2019 if (!set
->nr_hw_queues
)
2021 if (!set
->queue_depth
)
2023 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2026 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2029 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2030 pr_info("blk-mq: reduced tag depth to %u\n",
2032 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2035 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2036 sizeof(struct blk_mq_tags
*),
2037 GFP_KERNEL
, set
->numa_node
);
2041 if (blk_mq_alloc_rq_maps(set
))
2044 mutex_init(&set
->tag_list_lock
);
2045 INIT_LIST_HEAD(&set
->tag_list
);
2053 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2055 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2059 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2061 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2067 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2069 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2071 struct blk_mq_tag_set
*set
= q
->tag_set
;
2072 struct blk_mq_hw_ctx
*hctx
;
2075 if (!set
|| nr
> set
->queue_depth
)
2079 queue_for_each_hw_ctx(q
, hctx
, i
) {
2080 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2086 q
->nr_requests
= nr
;
2091 void blk_mq_disable_hotplug(void)
2093 mutex_lock(&all_q_mutex
);
2096 void blk_mq_enable_hotplug(void)
2098 mutex_unlock(&all_q_mutex
);
2101 static int __init
blk_mq_init(void)
2105 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2109 subsys_initcall(blk_mq_init
);