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| author | Ming Lei <ming.lei@redhat.com> | 2023-06-24 21:01:05 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-06-25 08:01:05 -0600 |
| commit | c6b7a3a26e809c9d2a51ae303764c1d2994f31cf (patch) | |
| tree | c921665f2b85359b6d17a68947868aa8d2a68fb1 /block/blk-mq.c | |
| parent | ad7c3b41e86b59943a903d23c7b037d820e6270c (diff) | |
| download | lwn-c6b7a3a26e809c9d2a51ae303764c1d2994f31cf.tar.gz lwn-c6b7a3a26e809c9d2a51ae303764c1d2994f31cf.zip | |
blk-mq: fix two misuses on RQF_USE_SCHED
Request allocated from sched tags can't be issued via ->queue_rqs()
directly, since driver tag isn't allocated yet. This is the 1st misuse
of RQF_USE_SCHED for figuring out plug->has_elevator.
Request allocated from sched tags can't be ended by
blk_mq_end_request_batch() too, fix the 2nd RQF_USE_SCHED misuse
in blk_mq_add_to_batch().
Without this patch, NVMe uring cmd passthrough IO workload can run into
hang easily with real io scheduler.
Fixes: dd6216bb16e8 ("blk-mq: make sure elevator callbacks aren't called for passthrough request")
Reported-by: Guangwu Zhang <guazhang@redhat.com>
Closes: https://lore.kernel.org/linux-block/CAGS2=YrBjpLPOKa-gzcKuuOG60AGth5794PNCDwatdnnscB9ug@mail.gmail.com/
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230624130105.1443879-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 720b5061ffe8..32e50bc0cbb0 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1280,7 +1280,11 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) if (!plug->multiple_queues && last && last->q != rq->q) plug->multiple_queues = true; - if (!plug->has_elevator && (rq->rq_flags & RQF_USE_SCHED)) + /* + * Any request allocated from sched tags can't be issued to + * ->queue_rqs() directly + */ + if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS)) plug->has_elevator = true; rq->rq_next = NULL; rq_list_add(&plug->mq_list, rq); |