exit/kthread: Have kernel threads return instead of calling do_exit

In 2009 Oleg reworked[1] the kernel threads so that it is not
necessary to call do_exit if you are not using kthread_stop().  Remove
the explicit calls of do_exit and complete_and_exit (with a NULL
completion) that were previously necessary.

[1] 63706172f332 ("kthreads: rework kthread_stop()")
Link: https://lkml.kernel.org/r/20211020174406.17889-12-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 4f15750..329986f 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1497,10 +1497,7 @@ static int __ocfs2_recovery_thread(void *arg)
 	if (quota_enabled)
 		kfree(rm_quota);
 
-	/* no one is callint kthread_stop() for us so the kthread() api
-	 * requires that we call do_exit().  And it isn't exported, but
-	 * complete_and_exit() seems to be a minimal wrapper around it. */
-	complete_and_exit(NULL, status);
+	return status;
 }
 
 void ocfs2_recovery_thread(struct ocfs2_super *osb, int node_num)