zram: destroy all devices on error recovery path in zram_init()

On error recovery path of zram_init(), it leaks the zram device object
causing the failure. So change create_device() to free allocated
resources on error path.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zram/zram_drv.c

@@ -595,7 +595,7 @@ static const struct block_device_operations zram_devops = {
 
 static int create_device(struct zram *zram, int device_id)
 {
-	int ret = 0;
+	int ret = -ENOMEM;
 
 	init_rwsem(&zram->lock);
 	init_rwsem(&zram->init_lock);
@@ -605,7 +605,6 @@ static int create_device(struct zram *zram, int device_id)
 	if (!zram->queue) {
 		pr_err("Error allocating disk queue for device %d\n",
 			device_id);
-		ret = -ENOMEM;
 		goto out;
 	}
 
@@ -615,11 +614,9 @@ static int create_device(struct zram *zram, int device_id)
 	 /* gendisk structure */
 	zram->disk = alloc_disk(1);
 	if (!zram->disk) {
-		blk_cleanup_queue(zram->queue);
 		pr_warn("Error allocating disk structure for device %d\n",
 			device_id);
-		ret = -ENOMEM;
-		goto out;
+		goto out_free_queue;
 	}
 
 	zram->disk->major = zram_major;
@@ -648,11 +645,17 @@ static int create_device(struct zram *zram, int device_id)
 				&zram_disk_attr_group);
 	if (ret < 0) {
 		pr_warn("Error creating sysfs group");
-		goto out;
+		goto out_free_disk;
 	}
 
 	zram->init_done = 0;
+	return 0;
 
+out_free_disk:
+	del_gendisk(zram->disk);
+	put_disk(zram->disk);
+out_free_queue:
+	blk_cleanup_queue(zram->queue);
 out:
 	return ret;
 }