From ebe8bddb6e30d7a02775b9972099271fc5910f37 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Fri, 7 Apr 2017 08:53:11 -0600 Subject: [PATCH] blk-mq: remap queues when adding/removing hardware queues 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") Reviewed-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe --- block/blk-mq.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index cfb7c97b14ec..f1be5c3eb600 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2570,6 +2570,14 @@ 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 @@ -2624,10 +2632,7 @@ 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; @@ -2719,6 +2724,7 @@ 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);