Revert "loop: Fold __loop_release into loop_release"

This reverts commit 7d839c10 which is
commit 967d1dc1 upstream.

It does not work properly in the 4.9.y tree and causes more problems
than it fixes, so revert it.
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Reported-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/block/loop.c

@@ -1575,15 +1575,12 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
 	return err;
 }
 
-static void lo_release(struct gendisk *disk, fmode_t mode)
+static void __lo_release(struct loop_device *lo)
 {
-	struct loop_device *lo;
 	int err;
 
-	mutex_lock(&loop_index_mutex);
-	lo = disk->private_data;
 	if (atomic_dec_return(&lo->lo_refcnt))
-		goto unlock_index;
+		return;
 
 	mutex_lock(&loop_ctl_mutex);
 	if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
@@ -1593,7 +1590,7 @@ static void lo_release(struct gendisk *disk, fmode_t mode)
 		 */
 		err = loop_clr_fd(lo);
 		if (!err)
-			goto unlock_index;
+			return;
 	} else {
 		/*
 		 * Otherwise keep thread (if running) and config,
@@ -1603,7 +1600,12 @@ static void lo_release(struct gendisk *disk, fmode_t mode)
 	}
 
 	mutex_unlock(&loop_ctl_mutex);
-unlock_index:
+}
+
+static void lo_release(struct gendisk *disk, fmode_t mode)
+{
+	mutex_lock(&loop_index_mutex);
+	__lo_release(disk->private_data);
 	mutex_unlock(&loop_index_mutex);
 }