1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/backing-dev.h>
5 #include <linux/blkdev.h>
7 #include <linux/init.h>
8 #include <linux/slab.h>
9 #include <linux/workqueue.h>
10 #include <linux/smp.h>
11 #include <linux/llist.h>
12 #include <linux/list_sort.h>
13 #include <linux/cpu.h>
14 #include <linux/cache.h>
15 #include <linux/sched/sysctl.h>
16 #include <linux/delay.h>
18 #include <trace/events/block.h>
20 #include <linux/blk-mq.h>
23 #include "blk-mq-tag.h"
25 static DEFINE_MUTEX(all_q_mutex
);
26 static LIST_HEAD(all_q_list
);
28 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
30 static struct blk_mq_ctx
*__blk_mq_get_ctx(struct request_queue
*q
,
33 return per_cpu_ptr(q
->queue_ctx
, cpu
);
37 * This assumes per-cpu software queueing queues. They could be per-node
38 * as well, for instance. For now this is hardcoded as-is. Note that we don't
39 * care about preemption, since we know the ctx's are persistent. This does
40 * mean that we can't rely on ctx always matching the currently running CPU.
42 static struct blk_mq_ctx
*blk_mq_get_ctx(struct request_queue
*q
)
44 return __blk_mq_get_ctx(q
, get_cpu());
47 static void blk_mq_put_ctx(struct blk_mq_ctx
*ctx
)
53 * Check if any of the ctx's have pending work in this hardware queue
55 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
59 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++)
60 if (hctx
->ctx_map
.map
[i
].word
)
66 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
67 struct blk_mq_ctx
*ctx
)
69 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
72 #define CTX_TO_BIT(hctx, ctx) \
73 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
76 * Mark this ctx as having pending work in this hardware queue
78 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
79 struct blk_mq_ctx
*ctx
)
81 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
83 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
84 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
87 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
88 struct blk_mq_ctx
*ctx
)
90 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
92 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
95 static struct request
*__blk_mq_alloc_request(struct blk_mq_hw_ctx
*hctx
,
96 struct blk_mq_ctx
*ctx
,
97 gfp_t gfp
, bool reserved
)
102 tag
= blk_mq_get_tag(hctx
, &ctx
->last_tag
, gfp
, reserved
);
103 if (tag
!= BLK_MQ_TAG_FAIL
) {
104 rq
= hctx
->tags
->rqs
[tag
];
107 if (blk_mq_tag_busy(hctx
)) {
108 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
109 atomic_inc(&hctx
->nr_active
);
119 static int blk_mq_queue_enter(struct request_queue
*q
)
123 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
125 /* we have problems to freeze the queue if it's initializing */
126 if (!blk_queue_bypass(q
) || !blk_queue_init_done(q
))
129 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
131 spin_lock_irq(q
->queue_lock
);
132 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
133 !blk_queue_bypass(q
) || blk_queue_dying(q
),
135 /* inc usage with lock hold to avoid freeze_queue runs here */
136 if (!ret
&& !blk_queue_dying(q
))
137 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
138 else if (blk_queue_dying(q
))
140 spin_unlock_irq(q
->queue_lock
);
145 static void blk_mq_queue_exit(struct request_queue
*q
)
147 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
150 static void __blk_mq_drain_queue(struct request_queue
*q
)
155 spin_lock_irq(q
->queue_lock
);
156 count
= percpu_counter_sum(&q
->mq_usage_counter
);
157 spin_unlock_irq(q
->queue_lock
);
161 blk_mq_run_queues(q
, false);
167 * Guarantee no request is in use, so we can change any data structure of
168 * the queue afterward.
170 static void blk_mq_freeze_queue(struct request_queue
*q
)
174 spin_lock_irq(q
->queue_lock
);
175 drain
= !q
->bypass_depth
++;
176 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
177 spin_unlock_irq(q
->queue_lock
);
180 __blk_mq_drain_queue(q
);
183 void blk_mq_drain_queue(struct request_queue
*q
)
185 __blk_mq_drain_queue(q
);
188 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
192 spin_lock_irq(q
->queue_lock
);
193 if (!--q
->bypass_depth
) {
194 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
197 WARN_ON_ONCE(q
->bypass_depth
< 0);
198 spin_unlock_irq(q
->queue_lock
);
200 wake_up_all(&q
->mq_freeze_wq
);
203 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
205 return blk_mq_has_free_tags(hctx
->tags
);
207 EXPORT_SYMBOL(blk_mq_can_queue
);
209 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
210 struct request
*rq
, unsigned int rw_flags
)
212 if (blk_queue_io_stat(q
))
213 rw_flags
|= REQ_IO_STAT
;
215 INIT_LIST_HEAD(&rq
->queuelist
);
216 /* csd/requeue_work/fifo_time is initialized before use */
219 rq
->cmd_flags
|= rw_flags
;
221 /* do not touch atomic flags, it needs atomic ops against the timer */
224 rq
->__sector
= (sector_t
) -1;
227 INIT_HLIST_NODE(&rq
->hash
);
228 RB_CLEAR_NODE(&rq
->rb_node
);
229 memset(&rq
->flush
, 0, max(sizeof(rq
->flush
), sizeof(rq
->elv
)));
232 rq
->start_time
= jiffies
;
233 #ifdef CONFIG_BLK_CGROUP
235 set_start_time_ns(rq
);
236 rq
->io_start_time_ns
= 0;
238 rq
->nr_phys_segments
= 0;
239 #if defined(CONFIG_BLK_DEV_INTEGRITY)
240 rq
->nr_integrity_segments
= 0;
244 /* tag was already set */
246 memset(rq
->__cmd
, 0, sizeof(rq
->__cmd
));
248 rq
->cmd_len
= BLK_MAX_CDB
;
256 INIT_LIST_HEAD(&rq
->timeout_list
);
260 rq
->end_io_data
= NULL
;
263 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
266 static struct request
*blk_mq_alloc_request_pinned(struct request_queue
*q
,
273 struct blk_mq_ctx
*ctx
= blk_mq_get_ctx(q
);
274 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
276 rq
= __blk_mq_alloc_request(hctx
, ctx
, gfp
& ~__GFP_WAIT
,
279 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
283 if (gfp
& __GFP_WAIT
) {
284 __blk_mq_run_hw_queue(hctx
);
291 blk_mq_wait_for_tags(hctx
, reserved
);
297 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
302 if (blk_mq_queue_enter(q
))
305 rq
= blk_mq_alloc_request_pinned(q
, rw
, gfp
, reserved
);
307 blk_mq_put_ctx(rq
->mq_ctx
);
310 EXPORT_SYMBOL(blk_mq_alloc_request
);
312 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
313 struct blk_mq_ctx
*ctx
, struct request
*rq
)
315 const int tag
= rq
->tag
;
316 struct request_queue
*q
= rq
->q
;
318 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
319 atomic_dec(&hctx
->nr_active
);
321 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
322 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
323 blk_mq_queue_exit(q
);
326 void blk_mq_free_request(struct request
*rq
)
328 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
329 struct blk_mq_hw_ctx
*hctx
;
330 struct request_queue
*q
= rq
->q
;
332 ctx
->rq_completed
[rq_is_sync(rq
)]++;
334 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
335 __blk_mq_free_request(hctx
, ctx
, rq
);
339 * Clone all relevant state from a request that has been put on hold in
340 * the flush state machine into the preallocated flush request that hangs
341 * off the request queue.
343 * For a driver the flush request should be invisible, that's why we are
344 * impersonating the original request here.
346 void blk_mq_clone_flush_request(struct request
*flush_rq
,
347 struct request
*orig_rq
)
349 struct blk_mq_hw_ctx
*hctx
=
350 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
352 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
353 flush_rq
->tag
= orig_rq
->tag
;
354 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
358 inline void __blk_mq_end_io(struct request
*rq
, int error
)
360 blk_account_io_done(rq
);
363 rq
->end_io(rq
, error
);
365 if (unlikely(blk_bidi_rq(rq
)))
366 blk_mq_free_request(rq
->next_rq
);
367 blk_mq_free_request(rq
);
370 EXPORT_SYMBOL(__blk_mq_end_io
);
372 void blk_mq_end_io(struct request
*rq
, int error
)
374 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
376 __blk_mq_end_io(rq
, error
);
378 EXPORT_SYMBOL(blk_mq_end_io
);
380 static void __blk_mq_complete_request_remote(void *data
)
382 struct request
*rq
= data
;
384 rq
->q
->softirq_done_fn(rq
);
387 void __blk_mq_complete_request(struct request
*rq
)
389 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
393 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
394 rq
->q
->softirq_done_fn(rq
);
399 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
400 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
402 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
403 rq
->csd
.func
= __blk_mq_complete_request_remote
;
406 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
408 rq
->q
->softirq_done_fn(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
)
423 struct request_queue
*q
= rq
->q
;
425 if (unlikely(blk_should_fake_timeout(q
)))
427 if (!blk_mark_rq_complete(rq
)) {
428 if (q
->softirq_done_fn
)
429 __blk_mq_complete_request(rq
);
431 blk_mq_end_io(rq
, rq
->errors
);
434 EXPORT_SYMBOL(blk_mq_complete_request
);
436 static void blk_mq_start_request(struct request
*rq
, bool last
)
438 struct request_queue
*q
= rq
->q
;
440 trace_block_rq_issue(q
, rq
);
442 rq
->resid_len
= blk_rq_bytes(rq
);
443 if (unlikely(blk_bidi_rq(rq
)))
444 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
447 * Just mark start time and set the started bit. Due to memory
448 * ordering, we know we'll see the correct deadline as long as
449 * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
450 * unless one has been set in the request.
453 rq
->deadline
= jiffies
+ q
->rq_timeout
;
455 rq
->deadline
= jiffies
+ rq
->timeout
;
458 * Mark us as started and clear complete. Complete might have been
459 * set if requeue raced with timeout, which then marked it as
460 * complete. So be sure to clear complete again when we start
461 * the request, otherwise we'll ignore the completion event.
463 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
464 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
466 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
468 * Make sure space for the drain appears. We know we can do
469 * this because max_hw_segments has been adjusted to be one
470 * fewer than the device can handle.
472 rq
->nr_phys_segments
++;
476 * Flag the last request in the series so that drivers know when IO
477 * should be kicked off, if they don't do it on a per-request basis.
479 * Note: the flag isn't the only condition drivers should do kick off.
480 * If drive is busy, the last request might not have the bit set.
483 rq
->cmd_flags
|= REQ_END
;
486 static void __blk_mq_requeue_request(struct request
*rq
)
488 struct request_queue
*q
= rq
->q
;
490 trace_block_rq_requeue(q
, rq
);
491 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
493 rq
->cmd_flags
&= ~REQ_END
;
495 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
496 rq
->nr_phys_segments
--;
499 void blk_mq_requeue_request(struct request
*rq
)
501 __blk_mq_requeue_request(rq
);
502 blk_clear_rq_complete(rq
);
504 BUG_ON(blk_queued_rq(rq
));
505 blk_mq_add_to_requeue_list(rq
, true);
507 EXPORT_SYMBOL(blk_mq_requeue_request
);
509 static void blk_mq_requeue_work(struct work_struct
*work
)
511 struct request_queue
*q
=
512 container_of(work
, struct request_queue
, requeue_work
);
514 struct request
*rq
, *next
;
517 spin_lock_irqsave(&q
->requeue_lock
, flags
);
518 list_splice_init(&q
->requeue_list
, &rq_list
);
519 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
521 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
522 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
525 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
526 list_del_init(&rq
->queuelist
);
527 blk_mq_insert_request(rq
, true, false, false);
530 while (!list_empty(&rq_list
)) {
531 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
532 list_del_init(&rq
->queuelist
);
533 blk_mq_insert_request(rq
, false, false, false);
536 blk_mq_run_queues(q
, false);
539 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
541 struct request_queue
*q
= rq
->q
;
545 * We abuse this flag that is otherwise used by the I/O scheduler to
546 * request head insertation from the workqueue.
548 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
550 spin_lock_irqsave(&q
->requeue_lock
, flags
);
552 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
553 list_add(&rq
->queuelist
, &q
->requeue_list
);
555 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
557 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
559 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
561 void blk_mq_kick_requeue_list(struct request_queue
*q
)
563 kblockd_schedule_work(&q
->requeue_work
);
565 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
567 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
569 return tags
->rqs
[tag
];
571 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
573 struct blk_mq_timeout_data
{
574 struct blk_mq_hw_ctx
*hctx
;
576 unsigned int *next_set
;
579 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
581 struct blk_mq_timeout_data
*data
= __data
;
582 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
585 /* It may not be in flight yet (this is where
586 * the REQ_ATOMIC_STARTED flag comes in). The requests are
587 * statically allocated, so we know it's always safe to access the
588 * memory associated with a bit offset into ->rqs[].
594 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
595 if (tag
>= hctx
->tags
->nr_tags
)
598 rq
= blk_mq_tag_to_rq(hctx
->tags
, tag
++);
599 if (rq
->q
!= hctx
->queue
)
601 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
604 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
608 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
610 unsigned int *next_set
)
612 struct blk_mq_timeout_data data
= {
615 .next_set
= next_set
,
619 * Ask the tagging code to iterate busy requests, so we can
620 * check them for timeout.
622 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
625 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
627 struct request_queue
*q
= rq
->q
;
630 * We know that complete is set at this point. If STARTED isn't set
631 * anymore, then the request isn't active and the "timeout" should
632 * just be ignored. This can happen due to the bitflag ordering.
633 * Timeout first checks if STARTED is set, and if it is, assumes
634 * the request is active. But if we race with completion, then
635 * we both flags will get cleared. So check here again, and ignore
636 * a timeout event with a request that isn't active.
638 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
639 return BLK_EH_NOT_HANDLED
;
641 if (!q
->mq_ops
->timeout
)
642 return BLK_EH_RESET_TIMER
;
644 return q
->mq_ops
->timeout(rq
);
647 static void blk_mq_rq_timer(unsigned long data
)
649 struct request_queue
*q
= (struct request_queue
*) data
;
650 struct blk_mq_hw_ctx
*hctx
;
651 unsigned long next
= 0;
654 queue_for_each_hw_ctx(q
, hctx
, i
) {
656 * If not software queues are currently mapped to this
657 * hardware queue, there's nothing to check
659 if (!hctx
->nr_ctx
|| !hctx
->tags
)
662 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
666 next
= blk_rq_timeout(round_jiffies_up(next
));
667 mod_timer(&q
->timeout
, next
);
669 queue_for_each_hw_ctx(q
, hctx
, i
)
670 blk_mq_tag_idle(hctx
);
675 * Reverse check our software queue for entries that we could potentially
676 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
677 * too much time checking for merges.
679 static bool blk_mq_attempt_merge(struct request_queue
*q
,
680 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
685 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
691 if (!blk_rq_merge_ok(rq
, bio
))
694 el_ret
= blk_try_merge(rq
, bio
);
695 if (el_ret
== ELEVATOR_BACK_MERGE
) {
696 if (bio_attempt_back_merge(q
, rq
, bio
)) {
701 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
702 if (bio_attempt_front_merge(q
, rq
, bio
)) {
714 * Process software queues that have been marked busy, splicing them
715 * to the for-dispatch
717 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
719 struct blk_mq_ctx
*ctx
;
722 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
723 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
724 unsigned int off
, bit
;
730 off
= i
* hctx
->ctx_map
.bits_per_word
;
732 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
733 if (bit
>= bm
->depth
)
736 ctx
= hctx
->ctxs
[bit
+ off
];
737 clear_bit(bit
, &bm
->word
);
738 spin_lock(&ctx
->lock
);
739 list_splice_tail_init(&ctx
->rq_list
, list
);
740 spin_unlock(&ctx
->lock
);
748 * Run this hardware queue, pulling any software queues mapped to it in.
749 * Note that this function currently has various problems around ordering
750 * of IO. In particular, we'd like FIFO behaviour on handling existing
751 * items on the hctx->dispatch list. Ignore that for now.
753 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
755 struct request_queue
*q
= hctx
->queue
;
760 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
762 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
768 * Touch any software queue that has pending entries.
770 flush_busy_ctxs(hctx
, &rq_list
);
773 * If we have previous entries on our dispatch list, grab them
774 * and stuff them at the front for more fair dispatch.
776 if (!list_empty_careful(&hctx
->dispatch
)) {
777 spin_lock(&hctx
->lock
);
778 if (!list_empty(&hctx
->dispatch
))
779 list_splice_init(&hctx
->dispatch
, &rq_list
);
780 spin_unlock(&hctx
->lock
);
784 * Now process all the entries, sending them to the driver.
787 while (!list_empty(&rq_list
)) {
790 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
791 list_del_init(&rq
->queuelist
);
793 blk_mq_start_request(rq
, list_empty(&rq_list
));
795 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
797 case BLK_MQ_RQ_QUEUE_OK
:
800 case BLK_MQ_RQ_QUEUE_BUSY
:
801 list_add(&rq
->queuelist
, &rq_list
);
802 __blk_mq_requeue_request(rq
);
805 pr_err("blk-mq: bad return on queue: %d\n", ret
);
806 case BLK_MQ_RQ_QUEUE_ERROR
:
808 blk_mq_end_io(rq
, rq
->errors
);
812 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
817 hctx
->dispatched
[0]++;
818 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
819 hctx
->dispatched
[ilog2(queued
) + 1]++;
822 * Any items that need requeuing? Stuff them into hctx->dispatch,
823 * that is where we will continue on next queue run.
825 if (!list_empty(&rq_list
)) {
826 spin_lock(&hctx
->lock
);
827 list_splice(&rq_list
, &hctx
->dispatch
);
828 spin_unlock(&hctx
->lock
);
833 * It'd be great if the workqueue API had a way to pass
834 * in a mask and had some smarts for more clever placement.
835 * For now we just round-robin here, switching for every
836 * BLK_MQ_CPU_WORK_BATCH queued items.
838 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
840 int cpu
= hctx
->next_cpu
;
842 if (--hctx
->next_cpu_batch
<= 0) {
845 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
846 if (next_cpu
>= nr_cpu_ids
)
847 next_cpu
= cpumask_first(hctx
->cpumask
);
849 hctx
->next_cpu
= next_cpu
;
850 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
856 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
858 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
861 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
862 __blk_mq_run_hw_queue(hctx
);
863 else if (hctx
->queue
->nr_hw_queues
== 1)
864 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
868 cpu
= blk_mq_hctx_next_cpu(hctx
);
869 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
873 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
875 struct blk_mq_hw_ctx
*hctx
;
878 queue_for_each_hw_ctx(q
, hctx
, i
) {
879 if ((!blk_mq_hctx_has_pending(hctx
) &&
880 list_empty_careful(&hctx
->dispatch
)) ||
881 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
885 blk_mq_run_hw_queue(hctx
, async
);
889 EXPORT_SYMBOL(blk_mq_run_queues
);
891 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
893 cancel_delayed_work(&hctx
->run_work
);
894 cancel_delayed_work(&hctx
->delay_work
);
895 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
897 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
899 void blk_mq_stop_hw_queues(struct request_queue
*q
)
901 struct blk_mq_hw_ctx
*hctx
;
904 queue_for_each_hw_ctx(q
, hctx
, i
)
905 blk_mq_stop_hw_queue(hctx
);
907 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
909 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
911 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
914 __blk_mq_run_hw_queue(hctx
);
917 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
919 void blk_mq_start_hw_queues(struct request_queue
*q
)
921 struct blk_mq_hw_ctx
*hctx
;
924 queue_for_each_hw_ctx(q
, hctx
, i
)
925 blk_mq_start_hw_queue(hctx
);
927 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
930 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
932 struct blk_mq_hw_ctx
*hctx
;
935 queue_for_each_hw_ctx(q
, hctx
, i
) {
936 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
939 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
941 blk_mq_run_hw_queue(hctx
, async
);
945 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
947 static void blk_mq_run_work_fn(struct work_struct
*work
)
949 struct blk_mq_hw_ctx
*hctx
;
951 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
953 __blk_mq_run_hw_queue(hctx
);
956 static void blk_mq_delay_work_fn(struct work_struct
*work
)
958 struct blk_mq_hw_ctx
*hctx
;
960 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
962 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
963 __blk_mq_run_hw_queue(hctx
);
966 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
968 unsigned long tmo
= msecs_to_jiffies(msecs
);
970 if (hctx
->queue
->nr_hw_queues
== 1)
971 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
975 cpu
= blk_mq_hctx_next_cpu(hctx
);
976 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
979 EXPORT_SYMBOL(blk_mq_delay_queue
);
981 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
982 struct request
*rq
, bool at_head
)
984 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
986 trace_block_rq_insert(hctx
->queue
, rq
);
989 list_add(&rq
->queuelist
, &ctx
->rq_list
);
991 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
993 blk_mq_hctx_mark_pending(hctx
, ctx
);
996 * We do this early, to ensure we are on the right CPU.
1001 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
1004 struct request_queue
*q
= rq
->q
;
1005 struct blk_mq_hw_ctx
*hctx
;
1006 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
1008 current_ctx
= blk_mq_get_ctx(q
);
1009 if (!cpu_online(ctx
->cpu
))
1010 rq
->mq_ctx
= ctx
= current_ctx
;
1012 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1014 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
1015 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
1016 blk_insert_flush(rq
);
1018 spin_lock(&ctx
->lock
);
1019 __blk_mq_insert_request(hctx
, rq
, at_head
);
1020 spin_unlock(&ctx
->lock
);
1024 blk_mq_run_hw_queue(hctx
, async
);
1026 blk_mq_put_ctx(current_ctx
);
1029 static void blk_mq_insert_requests(struct request_queue
*q
,
1030 struct blk_mq_ctx
*ctx
,
1031 struct list_head
*list
,
1036 struct blk_mq_hw_ctx
*hctx
;
1037 struct blk_mq_ctx
*current_ctx
;
1039 trace_block_unplug(q
, depth
, !from_schedule
);
1041 current_ctx
= blk_mq_get_ctx(q
);
1043 if (!cpu_online(ctx
->cpu
))
1045 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1048 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1051 spin_lock(&ctx
->lock
);
1052 while (!list_empty(list
)) {
1055 rq
= list_first_entry(list
, struct request
, queuelist
);
1056 list_del_init(&rq
->queuelist
);
1058 __blk_mq_insert_request(hctx
, rq
, false);
1060 spin_unlock(&ctx
->lock
);
1062 blk_mq_run_hw_queue(hctx
, from_schedule
);
1063 blk_mq_put_ctx(current_ctx
);
1066 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1068 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1069 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1071 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1072 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1073 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1076 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1078 struct blk_mq_ctx
*this_ctx
;
1079 struct request_queue
*this_q
;
1082 LIST_HEAD(ctx_list
);
1085 list_splice_init(&plug
->mq_list
, &list
);
1087 list_sort(NULL
, &list
, plug_ctx_cmp
);
1093 while (!list_empty(&list
)) {
1094 rq
= list_entry_rq(list
.next
);
1095 list_del_init(&rq
->queuelist
);
1097 if (rq
->mq_ctx
!= this_ctx
) {
1099 blk_mq_insert_requests(this_q
, this_ctx
,
1104 this_ctx
= rq
->mq_ctx
;
1110 list_add_tail(&rq
->queuelist
, &ctx_list
);
1114 * If 'this_ctx' is set, we know we have entries to complete
1115 * on 'ctx_list'. Do those.
1118 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1123 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1125 init_request_from_bio(rq
, bio
);
1126 blk_account_io_start(rq
, 1);
1129 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1130 struct blk_mq_ctx
*ctx
,
1131 struct request
*rq
, struct bio
*bio
)
1133 struct request_queue
*q
= hctx
->queue
;
1135 if (!(hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
)) {
1136 blk_mq_bio_to_request(rq
, bio
);
1137 spin_lock(&ctx
->lock
);
1139 __blk_mq_insert_request(hctx
, rq
, false);
1140 spin_unlock(&ctx
->lock
);
1143 spin_lock(&ctx
->lock
);
1144 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1145 blk_mq_bio_to_request(rq
, bio
);
1149 spin_unlock(&ctx
->lock
);
1150 __blk_mq_free_request(hctx
, ctx
, rq
);
1155 struct blk_map_ctx
{
1156 struct blk_mq_hw_ctx
*hctx
;
1157 struct blk_mq_ctx
*ctx
;
1160 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1162 struct blk_map_ctx
*data
)
1164 struct blk_mq_hw_ctx
*hctx
;
1165 struct blk_mq_ctx
*ctx
;
1167 int rw
= bio_data_dir(bio
);
1169 if (unlikely(blk_mq_queue_enter(q
))) {
1170 bio_endio(bio
, -EIO
);
1174 ctx
= blk_mq_get_ctx(q
);
1175 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1177 if (rw_is_sync(bio
->bi_rw
))
1180 trace_block_getrq(q
, bio
, rw
);
1181 rq
= __blk_mq_alloc_request(hctx
, ctx
, GFP_ATOMIC
, false);
1183 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
1185 blk_mq_put_ctx(ctx
);
1186 trace_block_sleeprq(q
, bio
, rw
);
1187 rq
= blk_mq_alloc_request_pinned(q
, rw
, __GFP_WAIT
|GFP_ATOMIC
,
1190 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1200 * Multiple hardware queue variant. This will not use per-process plugs,
1201 * but will attempt to bypass the hctx queueing if we can go straight to
1202 * hardware for SYNC IO.
1204 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1206 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1207 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1208 struct blk_map_ctx data
;
1211 blk_queue_bounce(q
, &bio
);
1213 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1214 bio_endio(bio
, -EIO
);
1218 rq
= blk_mq_map_request(q
, bio
, &data
);
1222 if (unlikely(is_flush_fua
)) {
1223 blk_mq_bio_to_request(rq
, bio
);
1224 blk_insert_flush(rq
);
1231 blk_mq_bio_to_request(rq
, bio
);
1232 blk_mq_start_request(rq
, true);
1235 * For OK queue, we are done. For error, kill it. Any other
1236 * error (busy), just add it to our list as we previously
1239 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1240 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1243 __blk_mq_requeue_request(rq
);
1245 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1247 blk_mq_end_io(rq
, rq
->errors
);
1253 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1255 * For a SYNC request, send it to the hardware immediately. For
1256 * an ASYNC request, just ensure that we run it later on. The
1257 * latter allows for merging opportunities and more efficient
1261 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1264 blk_mq_put_ctx(data
.ctx
);
1268 * Single hardware queue variant. This will attempt to use any per-process
1269 * plug for merging and IO deferral.
1271 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1273 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1274 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1275 unsigned int use_plug
, request_count
= 0;
1276 struct blk_map_ctx data
;
1280 * If we have multiple hardware queues, just go directly to
1281 * one of those for sync IO.
1283 use_plug
= !is_flush_fua
&& !is_sync
;
1285 blk_queue_bounce(q
, &bio
);
1287 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1288 bio_endio(bio
, -EIO
);
1292 if (use_plug
&& !blk_queue_nomerges(q
) &&
1293 blk_attempt_plug_merge(q
, bio
, &request_count
))
1296 rq
= blk_mq_map_request(q
, bio
, &data
);
1298 if (unlikely(is_flush_fua
)) {
1299 blk_mq_bio_to_request(rq
, bio
);
1300 blk_insert_flush(rq
);
1305 * A task plug currently exists. Since this is completely lockless,
1306 * utilize that to temporarily store requests until the task is
1307 * either done or scheduled away.
1310 struct blk_plug
*plug
= current
->plug
;
1313 blk_mq_bio_to_request(rq
, bio
);
1314 if (list_empty(&plug
->mq_list
))
1315 trace_block_plug(q
);
1316 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1317 blk_flush_plug_list(plug
, false);
1318 trace_block_plug(q
);
1320 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1321 blk_mq_put_ctx(data
.ctx
);
1326 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1328 * For a SYNC request, send it to the hardware immediately. For
1329 * an ASYNC request, just ensure that we run it later on. The
1330 * latter allows for merging opportunities and more efficient
1334 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1337 blk_mq_put_ctx(data
.ctx
);
1341 * Default mapping to a software queue, since we use one per CPU.
1343 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1345 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1347 EXPORT_SYMBOL(blk_mq_map_queue
);
1349 struct blk_mq_hw_ctx
*blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set
*set
,
1350 unsigned int hctx_index
,
1353 return kzalloc_node(sizeof(struct blk_mq_hw_ctx
), GFP_KERNEL
, node
);
1355 EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue
);
1357 void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx
*hctx
,
1358 unsigned int hctx_index
)
1362 EXPORT_SYMBOL(blk_mq_free_single_hw_queue
);
1364 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1365 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1369 if (tags
->rqs
&& set
->ops
->exit_request
) {
1372 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1375 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1380 while (!list_empty(&tags
->page_list
)) {
1381 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1382 list_del_init(&page
->lru
);
1383 __free_pages(page
, page
->private);
1388 blk_mq_free_tags(tags
);
1391 static size_t order_to_size(unsigned int order
)
1393 return (size_t)PAGE_SIZE
<< order
;
1396 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1397 unsigned int hctx_idx
)
1399 struct blk_mq_tags
*tags
;
1400 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1401 size_t rq_size
, left
;
1403 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1408 INIT_LIST_HEAD(&tags
->page_list
);
1410 tags
->rqs
= kmalloc_node(set
->queue_depth
* sizeof(struct request
*),
1411 GFP_KERNEL
, set
->numa_node
);
1413 blk_mq_free_tags(tags
);
1418 * rq_size is the size of the request plus driver payload, rounded
1419 * to the cacheline size
1421 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1423 left
= rq_size
* set
->queue_depth
;
1425 for (i
= 0; i
< set
->queue_depth
; ) {
1426 int this_order
= max_order
;
1431 while (left
< order_to_size(this_order
- 1) && this_order
)
1435 page
= alloc_pages_node(set
->numa_node
, GFP_KERNEL
,
1441 if (order_to_size(this_order
) < rq_size
)
1448 page
->private = this_order
;
1449 list_add_tail(&page
->lru
, &tags
->page_list
);
1451 p
= page_address(page
);
1452 entries_per_page
= order_to_size(this_order
) / rq_size
;
1453 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1454 left
-= to_do
* rq_size
;
1455 for (j
= 0; j
< to_do
; j
++) {
1457 if (set
->ops
->init_request
) {
1458 if (set
->ops
->init_request(set
->driver_data
,
1459 tags
->rqs
[i
], hctx_idx
, i
,
1472 pr_warn("%s: failed to allocate requests\n", __func__
);
1473 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1477 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1482 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1484 unsigned int bpw
= 8, total
, num_maps
, i
;
1486 bitmap
->bits_per_word
= bpw
;
1488 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1489 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1494 bitmap
->map_size
= num_maps
;
1497 for (i
= 0; i
< num_maps
; i
++) {
1498 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1499 total
-= bitmap
->map
[i
].depth
;
1505 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1507 struct request_queue
*q
= hctx
->queue
;
1508 struct blk_mq_ctx
*ctx
;
1512 * Move ctx entries to new CPU, if this one is going away.
1514 ctx
= __blk_mq_get_ctx(q
, cpu
);
1516 spin_lock(&ctx
->lock
);
1517 if (!list_empty(&ctx
->rq_list
)) {
1518 list_splice_init(&ctx
->rq_list
, &tmp
);
1519 blk_mq_hctx_clear_pending(hctx
, ctx
);
1521 spin_unlock(&ctx
->lock
);
1523 if (list_empty(&tmp
))
1526 ctx
= blk_mq_get_ctx(q
);
1527 spin_lock(&ctx
->lock
);
1529 while (!list_empty(&tmp
)) {
1532 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1534 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1537 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1538 blk_mq_hctx_mark_pending(hctx
, ctx
);
1540 spin_unlock(&ctx
->lock
);
1542 blk_mq_run_hw_queue(hctx
, true);
1543 blk_mq_put_ctx(ctx
);
1547 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1549 struct request_queue
*q
= hctx
->queue
;
1550 struct blk_mq_tag_set
*set
= q
->tag_set
;
1552 if (set
->tags
[hctx
->queue_num
])
1555 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1556 if (!set
->tags
[hctx
->queue_num
])
1559 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1563 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1566 struct blk_mq_hw_ctx
*hctx
= data
;
1568 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1569 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1570 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1571 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1576 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1577 struct blk_mq_tag_set
*set
, int nr_queue
)
1579 struct blk_mq_hw_ctx
*hctx
;
1582 queue_for_each_hw_ctx(q
, hctx
, i
) {
1586 if (set
->ops
->exit_hctx
)
1587 set
->ops
->exit_hctx(hctx
, i
);
1589 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1591 blk_mq_free_bitmap(&hctx
->ctx_map
);
1596 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1597 struct blk_mq_tag_set
*set
)
1599 struct blk_mq_hw_ctx
*hctx
;
1602 queue_for_each_hw_ctx(q
, hctx
, i
) {
1603 free_cpumask_var(hctx
->cpumask
);
1604 set
->ops
->free_hctx(hctx
, i
);
1608 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1609 struct blk_mq_tag_set
*set
)
1611 struct blk_mq_hw_ctx
*hctx
;
1615 * Initialize hardware queues
1617 queue_for_each_hw_ctx(q
, hctx
, i
) {
1620 node
= hctx
->numa_node
;
1621 if (node
== NUMA_NO_NODE
)
1622 node
= hctx
->numa_node
= set
->numa_node
;
1624 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1625 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1626 spin_lock_init(&hctx
->lock
);
1627 INIT_LIST_HEAD(&hctx
->dispatch
);
1629 hctx
->queue_num
= i
;
1630 hctx
->flags
= set
->flags
;
1631 hctx
->cmd_size
= set
->cmd_size
;
1633 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1634 blk_mq_hctx_notify
, hctx
);
1635 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1637 hctx
->tags
= set
->tags
[i
];
1640 * Allocate space for all possible cpus to avoid allocation in
1643 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1648 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1653 if (set
->ops
->init_hctx
&&
1654 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1658 if (i
== q
->nr_hw_queues
)
1664 blk_mq_exit_hw_queues(q
, set
, i
);
1669 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1670 unsigned int nr_hw_queues
)
1674 for_each_possible_cpu(i
) {
1675 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1676 struct blk_mq_hw_ctx
*hctx
;
1678 memset(__ctx
, 0, sizeof(*__ctx
));
1680 spin_lock_init(&__ctx
->lock
);
1681 INIT_LIST_HEAD(&__ctx
->rq_list
);
1684 /* If the cpu isn't online, the cpu is mapped to first hctx */
1688 hctx
= q
->mq_ops
->map_queue(q
, i
);
1689 cpumask_set_cpu(i
, hctx
->cpumask
);
1693 * Set local node, IFF we have more than one hw queue. If
1694 * not, we remain on the home node of the device
1696 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1697 hctx
->numa_node
= cpu_to_node(i
);
1701 static void blk_mq_map_swqueue(struct request_queue
*q
)
1704 struct blk_mq_hw_ctx
*hctx
;
1705 struct blk_mq_ctx
*ctx
;
1707 queue_for_each_hw_ctx(q
, hctx
, i
) {
1708 cpumask_clear(hctx
->cpumask
);
1713 * Map software to hardware queues
1715 queue_for_each_ctx(q
, ctx
, i
) {
1716 /* If the cpu isn't online, the cpu is mapped to first hctx */
1720 hctx
= q
->mq_ops
->map_queue(q
, i
);
1721 cpumask_set_cpu(i
, hctx
->cpumask
);
1722 ctx
->index_hw
= hctx
->nr_ctx
;
1723 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1726 queue_for_each_hw_ctx(q
, hctx
, i
) {
1728 * If not software queues are mapped to this hardware queue,
1729 * disable it and free the request entries
1731 if (!hctx
->nr_ctx
) {
1732 struct blk_mq_tag_set
*set
= q
->tag_set
;
1735 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1736 set
->tags
[i
] = NULL
;
1743 * Initialize batch roundrobin counts
1745 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1746 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1750 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1752 struct blk_mq_hw_ctx
*hctx
;
1753 struct request_queue
*q
;
1757 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1762 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1763 blk_mq_freeze_queue(q
);
1765 queue_for_each_hw_ctx(q
, hctx
, i
) {
1767 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1769 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1771 blk_mq_unfreeze_queue(q
);
1775 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1777 struct blk_mq_tag_set
*set
= q
->tag_set
;
1779 blk_mq_freeze_queue(q
);
1781 mutex_lock(&set
->tag_list_lock
);
1782 list_del_init(&q
->tag_set_list
);
1783 blk_mq_update_tag_set_depth(set
);
1784 mutex_unlock(&set
->tag_list_lock
);
1786 blk_mq_unfreeze_queue(q
);
1789 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1790 struct request_queue
*q
)
1794 mutex_lock(&set
->tag_list_lock
);
1795 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1796 blk_mq_update_tag_set_depth(set
);
1797 mutex_unlock(&set
->tag_list_lock
);
1800 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1802 struct blk_mq_hw_ctx
**hctxs
;
1803 struct blk_mq_ctx
*ctx
;
1804 struct request_queue
*q
;
1808 ctx
= alloc_percpu(struct blk_mq_ctx
);
1810 return ERR_PTR(-ENOMEM
);
1812 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1818 map
= blk_mq_make_queue_map(set
);
1822 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1823 int node
= blk_mq_hw_queue_to_node(map
, i
);
1825 hctxs
[i
] = set
->ops
->alloc_hctx(set
, i
, node
);
1829 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1832 atomic_set(&hctxs
[i
]->nr_active
, 0);
1833 hctxs
[i
]->numa_node
= node
;
1834 hctxs
[i
]->queue_num
= i
;
1837 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1841 if (percpu_counter_init(&q
->mq_usage_counter
, 0))
1844 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1845 blk_queue_rq_timeout(q
, 30000);
1847 q
->nr_queues
= nr_cpu_ids
;
1848 q
->nr_hw_queues
= set
->nr_hw_queues
;
1852 q
->queue_hw_ctx
= hctxs
;
1854 q
->mq_ops
= set
->ops
;
1855 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1857 q
->sg_reserved_size
= INT_MAX
;
1859 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1860 INIT_LIST_HEAD(&q
->requeue_list
);
1861 spin_lock_init(&q
->requeue_lock
);
1863 if (q
->nr_hw_queues
> 1)
1864 blk_queue_make_request(q
, blk_mq_make_request
);
1866 blk_queue_make_request(q
, blk_sq_make_request
);
1868 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1870 blk_queue_rq_timeout(q
, set
->timeout
);
1873 * Do this after blk_queue_make_request() overrides it...
1875 q
->nr_requests
= set
->queue_depth
;
1877 if (set
->ops
->complete
)
1878 blk_queue_softirq_done(q
, set
->ops
->complete
);
1880 blk_mq_init_flush(q
);
1881 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1883 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1884 set
->cmd_size
, cache_line_size()),
1889 if (blk_mq_init_hw_queues(q
, set
))
1892 mutex_lock(&all_q_mutex
);
1893 list_add_tail(&q
->all_q_node
, &all_q_list
);
1894 mutex_unlock(&all_q_mutex
);
1896 blk_mq_add_queue_tag_set(set
, q
);
1898 blk_mq_map_swqueue(q
);
1905 blk_cleanup_queue(q
);
1908 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1911 free_cpumask_var(hctxs
[i
]->cpumask
);
1912 set
->ops
->free_hctx(hctxs
[i
], i
);
1918 return ERR_PTR(-ENOMEM
);
1920 EXPORT_SYMBOL(blk_mq_init_queue
);
1922 void blk_mq_free_queue(struct request_queue
*q
)
1924 struct blk_mq_tag_set
*set
= q
->tag_set
;
1926 blk_mq_del_queue_tag_set(q
);
1928 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1929 blk_mq_free_hw_queues(q
, set
);
1931 percpu_counter_destroy(&q
->mq_usage_counter
);
1933 free_percpu(q
->queue_ctx
);
1934 kfree(q
->queue_hw_ctx
);
1937 q
->queue_ctx
= NULL
;
1938 q
->queue_hw_ctx
= NULL
;
1941 mutex_lock(&all_q_mutex
);
1942 list_del_init(&q
->all_q_node
);
1943 mutex_unlock(&all_q_mutex
);
1946 /* Basically redo blk_mq_init_queue with queue frozen */
1947 static void blk_mq_queue_reinit(struct request_queue
*q
)
1949 blk_mq_freeze_queue(q
);
1951 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1954 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1955 * we should change hctx numa_node according to new topology (this
1956 * involves free and re-allocate memory, worthy doing?)
1959 blk_mq_map_swqueue(q
);
1961 blk_mq_unfreeze_queue(q
);
1964 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1965 unsigned long action
, void *hcpu
)
1967 struct request_queue
*q
;
1970 * Before new mappings are established, hotadded cpu might already
1971 * start handling requests. This doesn't break anything as we map
1972 * offline CPUs to first hardware queue. We will re-init the queue
1973 * below to get optimal settings.
1975 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1976 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1979 mutex_lock(&all_q_mutex
);
1980 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1981 blk_mq_queue_reinit(q
);
1982 mutex_unlock(&all_q_mutex
);
1986 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
1990 if (!set
->nr_hw_queues
)
1992 if (!set
->queue_depth
|| set
->queue_depth
> BLK_MQ_MAX_DEPTH
)
1994 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
1997 if (!set
->nr_hw_queues
||
1998 !set
->ops
->queue_rq
|| !set
->ops
->map_queue
||
1999 !set
->ops
->alloc_hctx
|| !set
->ops
->free_hctx
)
2003 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2004 sizeof(struct blk_mq_tags
*),
2005 GFP_KERNEL
, set
->numa_node
);
2009 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2010 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2015 mutex_init(&set
->tag_list_lock
);
2016 INIT_LIST_HEAD(&set
->tag_list
);
2022 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2026 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2028 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2032 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2034 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2039 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2041 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2043 struct blk_mq_tag_set
*set
= q
->tag_set
;
2044 struct blk_mq_hw_ctx
*hctx
;
2047 if (!set
|| nr
> set
->queue_depth
)
2051 queue_for_each_hw_ctx(q
, hctx
, i
) {
2052 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2058 q
->nr_requests
= nr
;
2063 void blk_mq_disable_hotplug(void)
2065 mutex_lock(&all_q_mutex
);
2068 void blk_mq_enable_hotplug(void)
2070 mutex_unlock(&all_q_mutex
);
2073 static int __init
blk_mq_init(void)
2077 /* Must be called after percpu_counter_hotcpu_callback() */
2078 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
2082 subsys_initcall(blk_mq_init
);