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.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/md/dm-rq.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 5b95eea517d1..a896dea9750e 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -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);
--
2.31.1
--
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