From: Kemeng Shi shikemeng@huaweicloud.com
[ Upstream commit 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: f906a6a0f426 ("blk-mq: improve tag waiting setup for non-shared tags") Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index dc29a7c82bb82..8bc6778454e10 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1826,7 +1826,7 @@ 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; @@ -1849,6 +1849,10 @@ 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);