From: Ming Lei ming.lei@redhat.com
[ Upstream commit d97217e7f024bbe9aa62aea070771234c2879358 ]
Passthrough requests should never be queued to the I/O scheduler, as scheduling these opaque requests doesn't make sense, and I/O schedulers might require req->bio to be always valid.
We never let passthrough requests insert into the scheduler before commit 1c2d2fff6dc0 ("block: wire-up support for passthrough plugging"), restore this behavior even for passthrough requests issued under a plug.
[hch: use blk_mq_insert_requests for passthrough requests, fix up the commit message and comments]
Reported-by: Guangwu Zhang guazhang@redhat.com Closes: https://lore.kernel.org/linux-block/CAGS2=YosaYaUTEMU3uaf+y=8MqSrhL7sYsJn8Ew... Investigated-by: Yu Kuai yukuai1@huaweicloud.com Fixes: 1c2d2fff6dc0 ("block: wire-up support for passthrough plugging") Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230518053101.760632-2-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 850bfb844ed2f..c763f0bc66371 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2711,6 +2711,7 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) struct request *requeue_list = NULL; struct request **requeue_lastp = &requeue_list; unsigned int depth = 0; + bool is_passthrough = false; LIST_HEAD(list);
do { @@ -2719,7 +2720,9 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) if (!this_hctx) { this_hctx = rq->mq_hctx; this_ctx = rq->mq_ctx; - } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx) { + is_passthrough = blk_rq_is_passthrough(rq); + } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx || + is_passthrough != blk_rq_is_passthrough(rq)) { rq_list_add_tail(&requeue_lastp, rq); continue; } @@ -2731,7 +2734,8 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) trace_block_unplug(this_hctx->queue, depth, !from_sched);
percpu_ref_get(&this_hctx->queue->q_usage_counter); - if (this_hctx->queue->elevator) { + /* passthrough requests should never be issued to the I/O scheduler */ + if (this_hctx->queue->elevator && !is_passthrough) { this_hctx->queue->elevator->type->ops.insert_requests(this_hctx, &list, 0); blk_mq_run_hw_queue(this_hctx, from_sched);