audit: cleanup prune_tree_thread

We can use kthread_run instead of kthread_create+wake_up_process for
creating the thread.

We do not need to set the task state to TASK_RUNNING after schedule(),
the process is in that state already.

And we do not need to set the state to TASK_INTERRUPTIBLE when not
doing schedule() as we set the state to TASK_RUNNING immediately
afterwards.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: <linux-audit@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

kernel/audit_tree.c

@@ -661,10 +661,10 @@ static int tag_mount(struct vfsmount *mnt, void *arg)
 static int prune_tree_thread(void *unused)
 {
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		if (list_empty(&prune_list))
+		if (list_empty(&prune_list)) {
+			set_current_state(TASK_INTERRUPTIBLE);
 			schedule();
-		__set_current_state(TASK_RUNNING);
+		}
 
 		mutex_lock(&audit_cmd_mutex);
 		mutex_lock(&audit_filter_mutex);
@@ -693,16 +693,14 @@ static int audit_launch_prune(void)
 {
 	if (prune_thread)
 		return 0;
-	prune_thread = kthread_create(prune_tree_thread, NULL,
+	prune_thread = kthread_run(prune_tree_thread, NULL,
 				"audit_prune_tree");
 	if (IS_ERR(prune_thread)) {
 		pr_err("cannot start thread audit_prune_tree");
 		prune_thread = NULL;
 		return -ENOMEM;
-	} else {
-		wake_up_process(prune_thread);
-		return 0;
 	}
+	return 0;
 }
 
 /* called with audit_filter_mutex */