n64cart: 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/n64cart.c

@@ -115,6 +115,7 @@ static const struct block_device_operations n64cart_fops = {
 static int __init n64cart_probe(struct platform_device *pdev)
 {
 	struct gendisk *disk;
+	int err = -ENOMEM;
 
 	if (!start || !size) {
 		pr_err("start or size not specified\n");
@@ -132,7 +133,7 @@ static int __init n64cart_probe(struct platform_device *pdev)
 
 	disk = blk_alloc_disk(NUMA_NO_NODE);
 	if (!disk)
-		return -ENOMEM;
+		goto out;
 
 	disk->first_minor = 0;
 	disk->flags = GENHD_FL_NO_PART_SCAN;
@@ -147,11 +148,18 @@ static int __init n64cart_probe(struct platform_device *pdev)
 	blk_queue_physical_block_size(disk->queue, 4096);
 	blk_queue_logical_block_size(disk->queue, 4096);
 
-	add_disk(disk);
+	err = add_disk(disk);
+	if (err)
+		goto out_cleanup_disk;
 
 	pr_info("n64cart: %u kb disk\n", size / 1024);
 
 	return 0;
+
+out_cleanup_disk:
+	blk_cleanup_disk(disk);
+out:
+	return err;
 }
 
 static struct platform_driver n64cart_driver = {