blk-mq: Fix potential io hung for shared sbitmap per tagset
authorKemeng Shi <shikemeng@huaweicloud.com>
Wed, 18 Jan 2023 09:37:16 +0000 (17:37 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 10 Mar 2023 08:32:44 +0000 (09:32 +0100)
commitc9cf2f38cb1893170e4f316339bdf3ae132a4581
tree727dc87c1e40b5197f132517381d03c008b81181
parentb1f6feff7c6afff3b0fa834e7f192ecc87e7ce53
blk-mq: Fix potential io hung for shared sbitmap per tagset

[ Upstream commit 47df9ce95cd568d3f84218c4f65e9fbd4dfeda55 ]

Commit f906a6a0f4268 ("blk-mq: improve tag waiting setup for non-shared
tags") mark restart for unshared tags for improvement. At that time,
tags is only shared betweens queues and we can check if tags is shared
by test BLK_MQ_F_TAG_SHARED.
Afterwards, commit 32bc15afed04b ("blk-mq: Facilitate a shared sbitmap per
tagset") enabled tags share betweens hctxs inside a queue. We only
mark restart for shared hctxs inside a queue and may cause io hung if
there is no tag currently allocated by hctxs going to be marked restart.
Wait on sbitmap_queue instead of mark restart for shared hctxs case to
fix this.

Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/blk-mq.c