blk-mq: don't issue request directly in case that current is to be blocked

When flushing plug list in case that current will be blocked, we can't
issue request directly because ->queue_rq() may sleep, otherwise scheduler
may complain.

Fixes: dc5fc361d891 ("block: attempt direct issue of plug list")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211026082257.2889890-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c19dfa8..9840b15 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2223,7 +2223,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
                return;
        plug->rq_count = 0;
 
-       if (!plug->multiple_queues && !plug->has_elevator) {
+       if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
                blk_mq_plug_issue_direct(plug, from_schedule);
                if (rq_list_empty(plug->mq_list))
                        return;