rbd: call rbd_init_disk() sooner

Call rbd_init_disk() from rbd_add() as soon as we have the major
device number for the mapping.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

@@ -2623,10 +2623,16 @@ static ssize_t rbd_add(struct bus_type *bus,
 		goto err_out_id;
 	rbd_dev->major = rc;
 
-	rc = rbd_bus_add_dev(rbd_dev);
+	/* Set up the blkdev mapping. */
+
+	rc = rbd_init_disk(rbd_dev);
 	if (rc)
 		goto err_out_blkdev;
 
+	rc = rbd_bus_add_dev(rbd_dev);
+	if (rc)
+		goto err_out_disk;
+
 	/*
 	 * At this point cleanup in the event of an error is the job
 	 * of the sysfs code (initiated by rbd_bus_del_dev()).
@@ -2638,12 +2644,6 @@ static ssize_t rbd_add(struct bus_type *bus,
 	if (rc)
 		goto err_out_bus;
 
-	/* Set up the blkdev mapping. */
-
-	rc = rbd_init_disk(rbd_dev);
-	if (rc)
-		goto err_out_bus;
-
 	/* Everything's ready.  Announce the disk to the world. */
 
 	set_capacity(rbd_dev->disk, rbd_dev->mapping.size / SECTOR_SIZE);
@@ -2664,6 +2664,8 @@ static ssize_t rbd_add(struct bus_type *bus,
 	kfree(options);
 	return rc;
 
+err_out_disk:
+	rbd_free_disk(rbd_dev);
 err_out_blkdev:
 	unregister_blkdev(rbd_dev->major, rbd_dev->name);
 err_out_id: