MD: warn for potential deadlock
The personality thread shouldn't call mddev_suspend(). Because
mddev_suspend() will for all IO finish, but IO is handled in personality
thread, so this could cause deadlock. To trigger this early, add a
warning if mddev_suspend() is called from personality thread.
Suggested-by: NeilBrown <neilb@suse.com>
Cc: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 464627b..c068f17 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -305,6 +305,7 @@
*/
void mddev_suspend(struct mddev *mddev)
{
+ WARN_ON_ONCE(current == mddev->thread->tsk);
if (mddev->suspended++)
return;
synchronize_rcu();