blk-mq: make the sysfs mq/ layout reflect current mappings

Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.

Change this so that sysfs correctly reflects the current mappings
of the hardware queues.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 21f952ab3581..71f564e8812e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1924,6 +1924,8 @@ static void blk_mq_queue_reinit(struct request_queue *q)
 {
 	blk_mq_freeze_queue(q);
 
+	blk_mq_sysfs_unregister(q);
+
 	blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues);
 
 	/*
@@ -1934,6 +1936,8 @@ static void blk_mq_queue_reinit(struct request_queue *q)
 
 	blk_mq_map_swqueue(q);
 
+	blk_mq_sysfs_register(q);
+
 	blk_mq_unfreeze_queue(q);
 }