From: Ming Lei <ming.lei@redhat.com> mainline inclusion from mainline-v5.19 commit 6cfeadbff3f8905f2854735ebb88e581402c16c4 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5EKM7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- commit 364b61818f65 ("blk-mq: clearing flush request reference in tags->rqs[]") is added to clear the to-be-free flush request from tags->rqs[] for avoiding use-after-free on the flush rq. Yu Kuai reported that blk_mq_clear_flush_rq_mapping() slows down boot time by ~8s because running scsi probe which may create and remove lots of unpresent LUNs on megaraid-sas which uses BLK_MQ_F_TAG_HCTX_SHARED and each request queue has lots of hw queues. Improve the situation by not running blk_mq_clear_flush_rq_mapping if disk isn't added when there can't be any flush request issued. Reviewed-by: Christoph Hellwig <hch@lst.de> Reported-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220616014401.817001-4-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflicts: block/blk-mq.c Signed-off-by: Luo Meng <luomeng12@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- block/blk-mq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 41885145e57b..83193e44aada 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2737,8 +2737,9 @@ static void blk_mq_exit_hctx(struct request_queue *q, blk_mq_dtag_idle(hctx, true); } - blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx], - set->queue_depth, flush_rq); + if (blk_queue_init_done(q)) + blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx], + set->queue_depth, flush_rq); if (set->ops->exit_request) set->ops->exit_request(set, flush_rq, hctx_idx); -- 2.20.1