[PATCH v2] blk-mq: remap queues when adding/removing hardware queues
From: Omar Sandoval <osandov@osandov.com>
Date: 2017-03-31 20:44:47
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
From: Omar Sandoval <redacted>
blk_mq_update_nr_hw_queues() used to remap hardware queues, which is the
behavior that drivers expect. However, commit 4e68a011428a changed
blk_mq_queue_reinit() to not remap queues for the case of CPU
hotplugging, inadvertently making blk_mq_update_nr_hw_queues() not remap
queues as well. This breaks, for example, NBD's multi-connection mode,
leaving the added hardware queues unused. Fix it by making
blk_mq_update_nr_hw_queues() explicitly remap the queues.
Fixes: 4e68a011428a ("blk-mq: don't redistribute hardware queues on a CPU hotplug event")
Signed-off-by: Omar Sandoval <redacted>
---
block/blk-mq.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 061fc2cc88d3..70fa2b0d385a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -2478,6 +2478,14 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) return 0; } +static int blk_mq_update_queue_map(struct blk_mq_tag_set *set) +{ + if (set->ops->map_queues) + return set->ops->map_queues(set); + else + return blk_mq_map_queues(set); +} + /* * Alloc a tag set to be associated with one or more request queues. * May fail with EINVAL for various error conditions. May adjust the
@@ -2532,10 +2540,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) if (!set->mq_map) goto out_free_tags; - if (set->ops->map_queues) - ret = set->ops->map_queues(set); - else - ret = blk_mq_map_queues(set); + ret = blk_mq_update_queue_map(set); if (ret) goto out_free_mq_map;
@@ -2627,6 +2632,7 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) blk_mq_freeze_queue(q); set->nr_hw_queues = nr_hw_queues; + blk_mq_update_queue_map(set); list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_realloc_hw_ctxs(set, q); blk_mq_queue_reinit(q, cpu_online_mask);
@@ -2634,6 +2640,7 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_unfreeze_queue(q); + } EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
--
2.12.1