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authorMing Lei <ming.lei@redhat.com>2022-06-16 03:44:01 +0200
committerJens Axboe <axboe@kernel.dk>2022-06-16 22:45:15 +0200
commit6cfeadbff3f8905f2854735ebb88e581402c16c4 (patch)
treeedb82888efd3a884207c640f88837f5ab11fa0f3 /block
parentblk-mq: avoid to touch q->elevator without any protection (diff)
downloadlinux-6cfeadbff3f8905f2854735ebb88e581402c16c4.tar.xz
linux-6cfeadbff3f8905f2854735ebb88e581402c16c4.zip
blk-mq: don't clear flush_rq from tags->rqs[]
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4cdb08a70912..33145ba52c96 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3431,8 +3431,9 @@ static void blk_mq_exit_hctx(struct request_queue *q,
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_idle(hctx);
- 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);