If the worker thread is not woken due to a bio, then it is not woken at
all. This causes the hung task check to trigger. This occurs, for
instance, when no bios are submitted. Also when a delay of 0 is
configured, delay_bio() returns without waking the worker.

Prevent the hung task check from triggering by creating the thread with
kthread_run() instead of using kthread_create() directly.

Fixes: 70bbeb29fab0 ("dm delay: for short delays, use kthread instead of timers 
and wq")
Signed-off-by: Joel Colledge <[email protected]>
---
 drivers/md/dm-delay.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 5eabdb06c649..eac166405b6b 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -267,8 +267,7 @@ static int delay_ctr(struct dm_target *ti, unsigned int 
argc, char **argv)
                 * In case of small requested delays, use kthread instead of
                 * timers and workqueue to achieve better latency.
                 */
-               dc->worker = kthread_create(&flush_worker_fn, dc,
-                                           "dm-delay-flush-worker");
+               dc->worker = kthread_run(&flush_worker_fn, dc, 
"dm-delay-flush-worker");
                if (IS_ERR(dc->worker)) {
                        ret = PTR_ERR(dc->worker);
                        dc->worker = NULL;
-- 
2.34.1


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