From: Ming Lei ming.lei@redhat.com
commit b4459b11e84092658fa195a2587aff3b9637f0e7 upstream.
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: Ming Lei ming.lei@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-rq.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -490,6 +490,14 @@ static blk_status_t dm_mq_queue_rq(struc 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);