From 2293cae703cda162684ae966db6b1b4a11b5e88f Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 21 Jun 2023 21:22:08 +0800 Subject: [PATCH] blk-mq: don't insert passthrough request into sw queue In case of real io scheduler, q->elevator is set, so blk_mq_run_hw_queue() may just check if scheduler queue has request to dispatch, see __blk_mq_sched_dispatch_requests(). Then IO hang may be caused because all passthorugh requests may stay in sw queue. And any passthrough request should have been inserted to hctx->dispatch always. Reported-by: Guangwu Zhang Fixes: d97217e7f024 ("blk-mq: don't queue plugged passthrough requests into scheduler") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20230621132208.1142318-1-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-mq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 16c524e..720b506 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2728,7 +2728,12 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) percpu_ref_get(&this_hctx->queue->q_usage_counter); /* passthrough requests should never be issued to the I/O scheduler */ - if (this_hctx->queue->elevator && !is_passthrough) { + if (is_passthrough) { + spin_lock(&this_hctx->lock); + list_splice_tail_init(&list, &this_hctx->dispatch); + spin_unlock(&this_hctx->lock); + blk_mq_run_hw_queue(this_hctx, from_sched); + } else if (this_hctx->queue->elevator) { this_hctx->queue->elevator->type->ops.insert_requests(this_hctx, &list, 0); blk_mq_run_hw_queue(this_hctx, from_sched); -- 2.7.4