2 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
4 * This file is released under the GPL.
10 #include <linux/elevator.h> /* for rq_end_sector() */
11 #include <linux/blk-mq.h>
13 #define DM_MSG_PREFIX "core-rq"
15 #define DM_MQ_NR_HW_QUEUES 1
16 #define DM_MQ_QUEUE_DEPTH 2048
17 static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
18 static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
21 * Request-based DM's mempools' reserved IOs set by the user.
23 #define RESERVED_REQUEST_BASED_IOS 256
24 static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
26 static bool use_blk_mq = IS_ENABLED(CONFIG_DM_MQ_DEFAULT);
28 bool dm_use_blk_mq_default(void)
33 bool dm_use_blk_mq(struct mapped_device *md)
35 return md->use_blk_mq;
37 EXPORT_SYMBOL_GPL(dm_use_blk_mq);
39 unsigned dm_get_reserved_rq_based_ios(void)
41 return __dm_get_module_param(&reserved_rq_based_ios,
42 RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
44 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
46 static unsigned dm_get_blk_mq_nr_hw_queues(void)
48 return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
51 static unsigned dm_get_blk_mq_queue_depth(void)
53 return __dm_get_module_param(&dm_mq_queue_depth,
54 DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
57 int dm_request_based(struct mapped_device *md)
59 return queue_is_rq_based(md->queue);
62 static void dm_old_start_queue(struct request_queue *q)
66 spin_lock_irqsave(q->queue_lock, flags);
67 if (blk_queue_stopped(q))
69 spin_unlock_irqrestore(q->queue_lock, flags);
72 static void dm_mq_start_queue(struct request_queue *q)
74 blk_mq_unquiesce_queue(q);
75 blk_mq_kick_requeue_list(q);
78 void dm_start_queue(struct request_queue *q)
81 dm_old_start_queue(q);
86 static void dm_old_stop_queue(struct request_queue *q)
90 spin_lock_irqsave(q->queue_lock, flags);
91 if (!blk_queue_stopped(q))
93 spin_unlock_irqrestore(q->queue_lock, flags);
96 static void dm_mq_stop_queue(struct request_queue *q)
98 if (blk_mq_queue_stopped(q))
101 blk_mq_quiesce_queue(q);
104 void dm_stop_queue(struct request_queue *q)
107 dm_old_stop_queue(q);
113 * Partial completion handling for request-based dm
115 static void end_clone_bio(struct bio *clone)
117 struct dm_rq_clone_bio_info *info =
118 container_of(clone, struct dm_rq_clone_bio_info, clone);
119 struct dm_rq_target_io *tio = info->tio;
120 unsigned int nr_bytes = info->orig->bi_iter.bi_size;
121 blk_status_t error = clone->bi_status;
122 bool is_last = !clone->bi_next;
128 * An error has already been detected on the request.
129 * Once error occurred, just let clone->end_io() handle
135 * Don't notice the error to the upper layer yet.
136 * The error handling decision is made by the target driver,
137 * when the request is completed.
144 * I/O for the bio successfully completed.
145 * Notice the data completion to the upper layer.
147 tio->completed += nr_bytes;
150 * Update the original request.
151 * Do not use blk_end_request() here, because it may complete
152 * the original request before the clone, and break the ordering.
156 blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
159 static struct dm_rq_target_io *tio_from_request(struct request *rq)
161 return blk_mq_rq_to_pdu(rq);
164 static void rq_end_stats(struct mapped_device *md, struct request *orig)
166 if (unlikely(dm_stats_used(&md->stats))) {
167 struct dm_rq_target_io *tio = tio_from_request(orig);
168 tio->duration_jiffies = jiffies - tio->duration_jiffies;
169 dm_stats_account_io(&md->stats, rq_data_dir(orig),
170 blk_rq_pos(orig), tio->n_sectors, true,
171 tio->duration_jiffies, &tio->stats_aux);
176 * Don't touch any member of the md after calling this function because
177 * the md may be freed in dm_put() at the end of this function.
178 * Or do dm_get() before calling this function and dm_put() later.
180 static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
182 struct request_queue *q = md->queue;
185 atomic_dec(&md->pending[rw]);
187 /* nudge anyone waiting on suspend queue */
188 if (!md_in_flight(md))
192 * Run this off this callpath, as drivers could invoke end_io while
193 * inside their request_fn (and holding the queue lock). Calling
194 * back into ->request_fn() could deadlock attempting to grab the
197 if (!q->mq_ops && run_queue) {
198 spin_lock_irqsave(q->queue_lock, flags);
199 blk_run_queue_async(q);
200 spin_unlock_irqrestore(q->queue_lock, flags);
204 * dm_put() must be at the end of this function. See the comment above
210 * Complete the clone and the original request.
211 * Must be called without clone's queue lock held,
212 * see end_clone_request() for more details.
214 static void dm_end_request(struct request *clone, blk_status_t error)
216 int rw = rq_data_dir(clone);
217 struct dm_rq_target_io *tio = clone->end_io_data;
218 struct mapped_device *md = tio->md;
219 struct request *rq = tio->orig;
221 blk_rq_unprep_clone(clone);
222 tio->ti->type->release_clone_rq(clone);
224 rq_end_stats(md, rq);
226 blk_end_request_all(rq, error);
228 blk_mq_end_request(rq, error);
229 rq_completed(md, rw, true);
233 * Requeue the original request of a clone.
235 static void dm_old_requeue_request(struct request *rq, unsigned long delay_ms)
237 struct request_queue *q = rq->q;
240 spin_lock_irqsave(q->queue_lock, flags);
241 blk_requeue_request(q, rq);
242 blk_delay_queue(q, delay_ms);
243 spin_unlock_irqrestore(q->queue_lock, flags);
246 static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
248 blk_mq_delay_kick_requeue_list(q, msecs);
251 void dm_mq_kick_requeue_list(struct mapped_device *md)
253 __dm_mq_kick_requeue_list(dm_get_md_queue(md), 0);
255 EXPORT_SYMBOL(dm_mq_kick_requeue_list);
257 static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
259 blk_mq_requeue_request(rq, false);
260 __dm_mq_kick_requeue_list(rq->q, msecs);
263 static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)
265 struct mapped_device *md = tio->md;
266 struct request *rq = tio->orig;
267 int rw = rq_data_dir(rq);
268 unsigned long delay_ms = delay_requeue ? 100 : 0;
270 rq_end_stats(md, rq);
272 blk_rq_unprep_clone(tio->clone);
273 tio->ti->type->release_clone_rq(tio->clone);
277 dm_old_requeue_request(rq, delay_ms);
279 dm_mq_delay_requeue_request(rq, delay_ms);
281 rq_completed(md, rw, false);
284 static void dm_done(struct request *clone, blk_status_t error, bool mapped)
286 int r = DM_ENDIO_DONE;
287 struct dm_rq_target_io *tio = clone->end_io_data;
288 dm_request_endio_fn rq_end_io = NULL;
291 rq_end_io = tio->ti->type->rq_end_io;
293 if (mapped && rq_end_io)
294 r = rq_end_io(tio->ti, clone, error, &tio->info);
297 if (unlikely(error == BLK_STS_TARGET)) {
298 if (req_op(clone) == REQ_OP_WRITE_SAME &&
299 !clone->q->limits.max_write_same_sectors)
300 disable_write_same(tio->md);
301 if (req_op(clone) == REQ_OP_WRITE_ZEROES &&
302 !clone->q->limits.max_write_zeroes_sectors)
303 disable_write_zeroes(tio->md);
308 /* The target wants to complete the I/O */
309 dm_end_request(clone, error);
311 case DM_ENDIO_INCOMPLETE:
312 /* The target will handle the I/O */
314 case DM_ENDIO_REQUEUE:
315 /* The target wants to requeue the I/O */
316 dm_requeue_original_request(tio, false);
319 DMWARN("unimplemented target endio return value: %d", r);
325 * Request completion handler for request-based dm
327 static void dm_softirq_done(struct request *rq)
330 struct dm_rq_target_io *tio = tio_from_request(rq);
331 struct request *clone = tio->clone;
335 struct mapped_device *md = tio->md;
337 rq_end_stats(md, rq);
338 rw = rq_data_dir(rq);
340 blk_end_request_all(rq, tio->error);
342 blk_mq_end_request(rq, tio->error);
343 rq_completed(md, rw, false);
347 if (rq->rq_flags & RQF_FAILED)
350 dm_done(clone, tio->error, mapped);
354 * Complete the clone and the original request with the error status
355 * through softirq context.
357 static void dm_complete_request(struct request *rq, blk_status_t error)
359 struct dm_rq_target_io *tio = tio_from_request(rq);
363 blk_complete_request(rq);
365 blk_mq_complete_request(rq);
369 * Complete the not-mapped clone and the original request with the error status
370 * through softirq context.
371 * Target's rq_end_io() function isn't called.
372 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
374 static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
376 rq->rq_flags |= RQF_FAILED;
377 dm_complete_request(rq, error);
381 * Called with the clone's queue lock held (in the case of .request_fn)
383 static void end_clone_request(struct request *clone, blk_status_t error)
385 struct dm_rq_target_io *tio = clone->end_io_data;
388 * Actual request completion is done in a softirq context which doesn't
389 * hold the clone's queue lock. Otherwise, deadlock could occur because:
390 * - another request may be submitted by the upper level driver
391 * of the stacking during the completion
392 * - the submission which requires queue lock may be done
393 * against this clone's queue
395 dm_complete_request(tio->orig, error);
398 static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
402 if (blk_queue_io_stat(clone->q))
403 clone->rq_flags |= RQF_IO_STAT;
405 clone->start_time = jiffies;
406 r = blk_insert_cloned_request(clone->q, clone);
408 /* must complete clone in terms of original request */
409 dm_complete_request(rq, r);
412 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
415 struct dm_rq_target_io *tio = data;
416 struct dm_rq_clone_bio_info *info =
417 container_of(bio, struct dm_rq_clone_bio_info, clone);
419 info->orig = bio_orig;
421 bio->bi_end_io = end_clone_bio;
426 static int setup_clone(struct request *clone, struct request *rq,
427 struct dm_rq_target_io *tio, gfp_t gfp_mask)
431 r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
432 dm_rq_bio_constructor, tio);
436 clone->end_io = end_clone_request;
437 clone->end_io_data = tio;
444 static void map_tio_request(struct kthread_work *work);
446 static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
447 struct mapped_device *md)
456 * Avoid initializing info for blk-mq; it passes
457 * target-specific data through info.ptr
458 * (see: dm_mq_init_request)
460 if (!md->init_tio_pdu)
461 memset(&tio->info, 0, sizeof(tio->info));
462 if (md->kworker_task)
463 kthread_init_work(&tio->work, map_tio_request);
468 * DM_MAPIO_* : the request has been processed as indicated
469 * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
470 * < 0 : the request was completed due to failure
472 static int map_request(struct dm_rq_target_io *tio)
475 struct dm_target *ti = tio->ti;
476 struct mapped_device *md = tio->md;
477 struct request *rq = tio->orig;
478 struct request *clone = NULL;
480 r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
482 case DM_MAPIO_SUBMITTED:
483 /* The target has taken the I/O to submit by itself later */
485 case DM_MAPIO_REMAPPED:
486 if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
488 ti->type->release_clone_rq(clone);
489 return DM_MAPIO_REQUEUE;
492 /* The target has remapped the I/O so dispatch it */
493 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
495 dm_dispatch_clone_request(clone, rq);
497 case DM_MAPIO_REQUEUE:
498 /* The target wants to requeue the I/O */
500 case DM_MAPIO_DELAY_REQUEUE:
501 /* The target wants to requeue the I/O after a delay */
502 dm_requeue_original_request(tio, true);
505 /* The target wants to complete the I/O */
506 dm_kill_unmapped_request(rq, BLK_STS_IOERR);
509 DMWARN("unimplemented target map return value: %d", r);
516 static void dm_start_request(struct mapped_device *md, struct request *orig)
518 if (!orig->q->mq_ops)
519 blk_start_request(orig);
521 blk_mq_start_request(orig);
522 atomic_inc(&md->pending[rq_data_dir(orig)]);
524 if (md->seq_rq_merge_deadline_usecs) {
525 md->last_rq_pos = rq_end_sector(orig);
526 md->last_rq_rw = rq_data_dir(orig);
527 md->last_rq_start_time = ktime_get();
530 if (unlikely(dm_stats_used(&md->stats))) {
531 struct dm_rq_target_io *tio = tio_from_request(orig);
532 tio->duration_jiffies = jiffies;
533 tio->n_sectors = blk_rq_sectors(orig);
534 dm_stats_account_io(&md->stats, rq_data_dir(orig),
535 blk_rq_pos(orig), tio->n_sectors, false, 0,
540 * Hold the md reference here for the in-flight I/O.
541 * We can't rely on the reference count by device opener,
542 * because the device may be closed during the request completion
543 * when all bios are completed.
544 * See the comment in rq_completed() too.
549 static int __dm_rq_init_rq(struct mapped_device *md, struct request *rq)
551 struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
554 * Must initialize md member of tio, otherwise it won't
555 * be available in dm_mq_queue_rq.
559 if (md->init_tio_pdu) {
560 /* target-specific per-io data is immediately after the tio */
561 tio->info.ptr = tio + 1;
567 static int dm_rq_init_rq(struct request_queue *q, struct request *rq, gfp_t gfp)
569 return __dm_rq_init_rq(q->rq_alloc_data, rq);
572 static void map_tio_request(struct kthread_work *work)
574 struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
576 if (map_request(tio) == DM_MAPIO_REQUEUE)
577 dm_requeue_original_request(tio, false);
580 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
582 return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
585 #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
587 ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
588 const char *buf, size_t count)
592 if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED)
595 if (kstrtouint(buf, 10, &deadline))
598 if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
599 deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
601 md->seq_rq_merge_deadline_usecs = deadline;
606 static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md)
610 if (!md->seq_rq_merge_deadline_usecs)
613 kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
614 kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
616 return !ktime_after(ktime_get(), kt_deadline);
620 * q->request_fn for old request-based dm.
621 * Called with the queue lock held.
623 static void dm_old_request_fn(struct request_queue *q)
625 struct mapped_device *md = q->queuedata;
626 struct dm_target *ti = md->immutable_target;
628 struct dm_rq_target_io *tio;
633 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
635 if (unlikely(!map)) {
636 dm_put_live_table(md, srcu_idx);
639 ti = dm_table_find_target(map, pos);
640 dm_put_live_table(md, srcu_idx);
644 * For suspend, check blk_queue_stopped() and increment
645 * ->pending within a single queue_lock not to increment the
646 * number of in-flight I/Os after the queue is stopped in
649 while (!blk_queue_stopped(q)) {
650 rq = blk_peek_request(q);
654 /* always use block 0 to find the target for flushes for now */
656 if (req_op(rq) != REQ_OP_FLUSH)
657 pos = blk_rq_pos(rq);
659 if ((dm_old_request_peeked_before_merge_deadline(md) &&
660 md_in_flight(md) && rq->bio && !bio_multiple_segments(rq->bio) &&
661 md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) ||
662 (ti->type->busy && ti->type->busy(ti))) {
663 blk_delay_queue(q, 10);
667 dm_start_request(md, rq);
669 tio = tio_from_request(rq);
670 init_tio(tio, rq, md);
671 /* Establish tio->ti before queuing work (map_tio_request) */
673 kthread_queue_work(&md->kworker, &tio->work);
674 BUG_ON(!irqs_disabled());
679 * Fully initialize a .request_fn request-based queue.
681 int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
683 struct dm_target *immutable_tgt;
685 /* Fully initialize the queue */
686 md->queue->cmd_size = sizeof(struct dm_rq_target_io);
687 md->queue->rq_alloc_data = md;
688 md->queue->request_fn = dm_old_request_fn;
689 md->queue->init_rq_fn = dm_rq_init_rq;
691 immutable_tgt = dm_table_get_immutable_target(t);
692 if (immutable_tgt && immutable_tgt->per_io_data_size) {
693 /* any target-specific per-io data is immediately after the tio */
694 md->queue->cmd_size += immutable_tgt->per_io_data_size;
695 md->init_tio_pdu = true;
697 if (blk_init_allocated_queue(md->queue) < 0)
700 /* disable dm_old_request_fn's merge heuristic by default */
701 md->seq_rq_merge_deadline_usecs = 0;
703 dm_init_normal_md_queue(md);
704 blk_queue_softirq_done(md->queue, dm_softirq_done);
706 /* Initialize the request-based DM worker thread */
707 kthread_init_worker(&md->kworker);
708 md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
709 "kdmwork-%s", dm_device_name(md));
710 if (IS_ERR(md->kworker_task)) {
711 int error = PTR_ERR(md->kworker_task);
712 md->kworker_task = NULL;
716 elv_register_queue(md->queue);
721 static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
722 unsigned int hctx_idx, unsigned int numa_node)
724 return __dm_rq_init_rq(set->driver_data, rq);
727 static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
728 const struct blk_mq_queue_data *bd)
730 struct request *rq = bd->rq;
731 struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
732 struct mapped_device *md = tio->md;
733 struct dm_target *ti = md->immutable_target;
737 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
739 ti = dm_table_find_target(map, 0);
740 dm_put_live_table(md, srcu_idx);
743 if (ti->type->busy && ti->type->busy(ti))
744 return BLK_STS_RESOURCE;
746 dm_start_request(md, rq);
748 /* Init tio using md established in .init_request */
749 init_tio(tio, rq, md);
752 * Establish tio->ti before calling map_request().
756 /* Direct call is fine since .queue_rq allows allocations */
757 if (map_request(tio) == DM_MAPIO_REQUEUE) {
758 /* Undo dm_start_request() before requeuing */
759 rq_end_stats(md, rq);
760 rq_completed(md, rq_data_dir(rq), false);
761 blk_mq_delay_run_hw_queue(hctx, 100/*ms*/);
762 return BLK_STS_RESOURCE;
768 static const struct blk_mq_ops dm_mq_ops = {
769 .queue_rq = dm_mq_queue_rq,
770 .complete = dm_softirq_done,
771 .init_request = dm_mq_init_request,
774 int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
776 struct request_queue *q;
777 struct dm_target *immutable_tgt;
780 if (!dm_table_all_blk_mq_devices(t)) {
781 DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
785 md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
789 md->tag_set->ops = &dm_mq_ops;
790 md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
791 md->tag_set->numa_node = md->numa_node_id;
792 md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
793 md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
794 md->tag_set->driver_data = md;
796 md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
797 immutable_tgt = dm_table_get_immutable_target(t);
798 if (immutable_tgt && immutable_tgt->per_io_data_size) {
799 /* any target-specific per-io data is immediately after the tio */
800 md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
801 md->init_tio_pdu = true;
804 err = blk_mq_alloc_tag_set(md->tag_set);
806 goto out_kfree_tag_set;
808 q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
813 dm_init_md_queue(md);
815 /* backfill 'mq' sysfs registration normally done in blk_register_queue */
816 err = blk_mq_register_dev(disk_to_dev(md->disk), q);
818 goto out_cleanup_queue;
823 blk_cleanup_queue(q);
825 blk_mq_free_tag_set(md->tag_set);
832 void dm_mq_cleanup_mapped_device(struct mapped_device *md)
835 blk_mq_free_tag_set(md->tag_set);
840 module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
841 MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
843 module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
844 MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
846 module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
847 MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
849 module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
850 MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");