loop: Fold __loop_release into loop_release

__loop_release() has a single call site. Fold it there. This is
currently not a huge win but it will make following replacement of
loop_index_mutex more obvious.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/loop.c

@@ -1641,12 +1641,15 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
 	return err;
 }
 
-static void __lo_release(struct loop_device *lo)
+static void lo_release(struct gendisk *disk, fmode_t mode)
 {
+	struct loop_device *lo;
 	int err;
 
+	mutex_lock(&loop_index_mutex);
+	lo = disk->private_data;
 	if (atomic_dec_return(&lo->lo_refcnt))
-		return;
+		goto unlock_index;
 
 	mutex_lock(&loop_ctl_mutex);
 	if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
@@ -1656,7 +1659,7 @@ static void __lo_release(struct loop_device *lo)
 		 */
 		err = loop_clr_fd(lo);
 		if (!err)
-			return;
+			goto unlock_index;
 	} else if (lo->lo_state == Lo_bound) {
 		/*
 		 * Otherwise keep thread (if running) and config,
@@ -1667,12 +1670,7 @@ static void __lo_release(struct loop_device *lo)
 	}
 
 	mutex_unlock(&loop_ctl_mutex);
-}
-
-static void lo_release(struct gendisk *disk, fmode_t mode)
-{
-	mutex_lock(&loop_index_mutex);
-	__lo_release(disk->private_data);
+unlock_index:
 	mutex_unlock(&loop_index_mutex);
 }