Commit b4459b11 authored by Ming Lei's avatar Ming Lei Committed by Mike Snitzer
Browse files

dm rq: don't queue request to blk-mq during DM suspend 



DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.

But blk-mq's unquiesce may come from outside events, such as elevator
switch, updating nr_requests or others, and request may come during
suspend, so simply ask for blk-mq to requeue it.

Fixes one kernel panic issue when running updating nr_requests and
dm-mpath suspend/resume stress test.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent ec132ef2

drivers/md/dm-rq.c

+8 −0
Original line number Diff line number Diff line
@@ -490,6 +490,14 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, 
	struct mapped_device *md = tio->md;

	struct dm_target *ti = md->immutable_target;



	/*

	 * blk-mq's unquiesce may come from outside events, such as

	 * elevator switch, updating nr_requests or others, and request may

	 * come during suspend, so simply ask for blk-mq to requeue it.

	 */

	if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)))

		return BLK_STS_RESOURCE;



	if (unlikely(!ti)) {

		int srcu_idx;

		struct dm_table *map = dm_get_live_table(md, &srcu_idx);