Commit fba8b302 authored by Kemeng Shi's avatar Kemeng Shi Committed by Yu Kuai
Browse files

blk-mq: wait on correct sbitmap_queue in blk_mq_mark_tag_wait 

mainline inclusion
from mainline-v6.3-rc1
commit 98b99e94
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAQPKU
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=98b99e9412d0cde8c7b442bf5efb09528a2ede8b



--------------------------------

For shared queues case, we will only wait on bitmap_tags if we fail to get
driver tag. However, rq could be from breserved_tags, then two problems
will occur:
1. io hung if no tag is currently allocated from bitmap_tags.
2. unnecessary wakeup when tag is freed to bitmap_tags while no tag is
freed to breserved_tags.
Wait on the bitmap which rq from to fix this.

Fixes: f906a6a0 ("blk-mq: improve tag waiting setup for non-shared tags")
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
parent b8df1b05

block/blk-mq.c

+5 −1
Original line number Diff line number Diff line
@@ -1240,7 +1240,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, 
static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,

				 struct request *rq)

{

	struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags;

	struct sbitmap_queue *sbq;

	struct wait_queue_head *wq;

	wait_queue_entry_t *wait;

	bool ret;
@@ -1263,6 +1263,10 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, 
	if (!list_empty_careful(&wait->entry))

		return false;



	if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))

		sbq = &hctx->tags->breserved_tags;

	else

		sbq = &hctx->tags->bitmap_tags;

	wq = &bt_wait_ptr(sbq, hctx)->wait;



	spin_lock_irq(&wq->lock);