block: block new I/O just after queue is set as dying
authorMing Lei <tom.leiming@gmail.com>
Mon, 27 Mar 2017 12:06:58 +0000 (20:06 +0800)
committerJens Axboe <axboe@fb.com>
Wed, 29 Mar 2017 14:03:42 +0000 (08:03 -0600)
commitd3cfb2a0ac0b8487d28a1ee207c29617bf6e6820
tree85c3948ceda4296641bebd97fe1fbd177481a14d
parent1671d522cdd9933dee7dddfcf9f62c561283824a
block: block new I/O just after queue is set as dying

Before commit 780db2071a(blk-mq: decouble blk-mq freezing
from generic bypassing), the dying flag is checked before
entering queue, and Tejun converts the checking into .mq_freeze_depth,
and assumes the counter is increased just after dying flag
is set. Unfortunately we doesn't do that in blk_set_queue_dying().

This patch calls blk_freeze_queue_start() in blk_set_queue_dying(),
so that we can block new I/O coming once the queue is set as dying.

Given blk_set_queue_dying() is always called in remove path
of block device, and queue will be cleaned up later, we don't
need to worry about undoing the counter.

Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-core.c