block: cleanup __alloc_disk_node

Use early returns and goto-based unwinding to simplify the flow a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -1729,19 +1729,20 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	}
 
 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
-	if (disk) {
-		disk->part0.dkstats = alloc_percpu(struct disk_stats);
-		if (!disk->part0.dkstats) {
-			kfree(disk);
+	if (!disk)
 		return NULL;
-		}
+
+	disk->part0.dkstats = alloc_percpu(struct disk_stats);
+	if (!disk->part0.dkstats)
+		goto out_free_disk;
+
 	init_rwsem(&disk->lookup_sem);
 	disk->node_id = node_id;
 	if (disk_expand_part_tbl(disk, 0)) {
 		free_percpu(disk->part0.dkstats);
-			kfree(disk);
-			return NULL;
+		goto out_free_disk;
 	}
+
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 	rcu_assign_pointer(ptbl->part[0], &disk->part0);
 
@@ -1755,19 +1756,21 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	 * converted to make use of bd_mutex and sequence counters.
 	 */
 	hd_sects_seq_init(&disk->part0);
-		if (hd_ref_init(&disk->part0)) {
-			hd_free_part(&disk->part0);
-			kfree(disk);
-			return NULL;
-		}
+	if (hd_ref_init(&disk->part0))
+		goto out_free_part0;
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
 	disk_to_dev(disk)->class = &block_class;
 	disk_to_dev(disk)->type = &disk_type;
 	device_initialize(disk_to_dev(disk));
-	}
 	return disk;
+
+out_free_part0:
+	hd_free_part(&disk->part0);
+out_free_disk:
+	kfree(disk);
+	return NULL;
 }
 EXPORT_SYMBOL(__alloc_disk_node);