block/brd: 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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/brd.c

···
 	struct brd_device *brd;
 	struct gendisk *disk;
 	char buf[DISK_NAME_LEN];
+	int err = -ENOMEM;
 
 	mutex_lock(&brd_devices_mutex);
 	list_for_each_entry(brd, &brd_devices, brd_list) {
···
 	/* Tell the block layer that this is not a rotational device */
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
 	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
-	add_disk(disk);
+	err = add_disk(disk);
+	if (err)
+		goto out_cleanup_disk;
 
 	return 0;
 
+out_cleanup_disk:
+	blk_cleanup_disk(disk);
 out_free_dev:
 	mutex_lock(&brd_devices_mutex);
 	list_del(&brd->brd_list);
 	mutex_unlock(&brd_devices_mutex);
 	kfree(brd);
-	return -ENOMEM;
+	return err;
 }
 
 static void brd_probe(dev_t dev)