Commit 2293cae7 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

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: default avatarGuangwu Zhang <guazhang@redhat.com>
Fixes: d97217e7 ("blk-mq: don't queue plugged passthrough requests into scheduler")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230621132208.1142318-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 72ef02b8

block/blk-mq.c

+6 −1
Original line number Diff line number Diff line
@@ -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);