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blk-mq: Fix potential io hung for shared sbitmap per tagset 

[ Upstream commit 47df9ce95c ]

Commit f906a6a0f4 ("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 32bc15afed ("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: 32bc15afed ("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>
This commit is contained in:
Kemeng Shi 2023-01-18 17:37:16 +08:00 committed by Greg Kroah-Hartman
parent b1f6feff7c
commit c9cf2f38cb
1 changed files with 4 additions and 2 deletions
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6
block/blk-mq.c
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@ -1799,7 +1799,8 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
wait_queue_entry_t *wait;
bool ret;
if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
!(blk_mq_is_shared_tags(hctx->flags))) {
blk_mq_sched_mark_restart_hctx(hctx);
/*
@ -2069,7 +2070,8 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
bool needs_restart;
/* For non-shared tags, the RESTART check will suffice */
bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED);
((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
blk_mq_is_shared_tags(hctx->flags));
if (nr_budgets)
blk_mq_release_budgets(q, list);