drbd: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/drbd/drbd_main.c

@@ -2794,7 +2794,9 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 		goto out_idr_remove_vol;
 	}
 
-	add_disk(disk);
+	err = add_disk(disk);
+	if (err)
+		goto out_cleanup_disk;
 
 	/* inherit the connection state */
 	device->state.conn = first_connection(resource)->cstate;
@@ -2808,6 +2810,8 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	drbd_debugfs_device_add(device);
 	return NO_ERROR;
 
+out_cleanup_disk:
+	blk_cleanup_disk(disk);
 out_idr_remove_vol:
 	idr_remove(&connection->peer_devices, vnr);
 out_idr_remove_from_resource: