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...
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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);