[JFFS2] Fix cleanup in case of GC-Task not started

Do not call wait_for_completion, when the gc task is not there. 
Prevent an oops when the gc thread was not started.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

fs/jffs2/background.c

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: background.c,v 1.52 2005/05/19 16:18:08 gleixner Exp $
+ * $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $
  *
  */
 
@@ -56,13 +56,16 @@ int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
 
 void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
 {
+	int wait = 0;
 	spin_lock(&c->erase_completion_lock);
 	if (c->gc_task) {
 		D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
 		send_sig(SIGKILL, c->gc_task, 1);
+		wait = 1;
 	}
 	spin_unlock(&c->erase_completion_lock);
-	wait_for_completion(&c->gc_thread_exit);
+	if (wait)
+		wait_for_completion(&c->gc_thread_exit);
 }
 
 static int jffs2_garbage_collect_thread(void *_c)