fs: dlm: check on plock ops when exit dlm

To be sure we don't have any issues that there are leftover plock ops in
either send_list or recv_list we simple check if either one of the list
are empty when we exit the dlm subsystem.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/plock.c

@@ -628,5 +628,7 @@ int dlm_plock_init(void)
 void dlm_plock_exit(void)
 {
 	misc_deregister(&plock_dev_misc);
+	WARN_ON(!list_empty(&send_list));
+	WARN_ON(!list_empty(&recv_list));
 }