[PATCH] md: Convert reconfig_sem to reconfig_mutex

... being careful that mutex_trylock is inverted wrt down_trylock

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index c0d3097..e2df61f 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -185,7 +185,7 @@
 	unsigned long			recovery;
 
 	int				in_sync;	/* know to not need resync */
-	struct semaphore		reconfig_sem;
+	struct mutex			reconfig_mutex;
 	atomic_t			active;
 
 	int				changed;	/* true if we might need to reread partition info */