diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 02acd5d5a848..08a7f97750f7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2407,8 +2407,6 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 	} else
 		err = -ENOMEM;
 
-	mutex_unlock(&conf->cache_size_mutex);
-
 	conf->slab_cache = sc;
 	conf->active_name = 1-conf->active_name;
 
@@ -2431,6 +2429,8 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 
 	if (!err)
 		conf->pool_size = newsize;
+	mutex_unlock(&conf->cache_size_mutex);
+
 	return err;
 }