Re: [PATCH v4 02/27] btrfs: Get zone information of zoned block devices

[Johannes Thumshirn <jthumshirn@suse.de>]

On 23/08/2019 12:10, Naohiro Aota wrote:
[...]
> +int btrfs_get_dev_zone_info(struct btrfs_device *device)
> +{
> +	struct btrfs_zoned_device_info *zone_info = NULL;
> +	struct block_device *bdev = device->bdev;
> +	sector_t nr_sectors = bdev->bd_part->nr_sects;
> +	sector_t sector = 0;
> +	struct blk_zone *zones = NULL;
> +	unsigned int i, nreported = 0, nr_zones;
> +	unsigned int zone_sectors;
> +	int ret;
> +
> +	if (!bdev_is_zoned(bdev))
> +		return 0;
> +
> +	zone_info = kzalloc(sizeof(*zone_info), GFP_KERNEL);
> +	if (!zone_info)
> +		return -ENOMEM;
> +
> +	zone_sectors = bdev_zone_sectors(bdev);
> +	ASSERT(is_power_of_2(zone_sectors));
> +	zone_info->zone_size = (u64)zone_sectors << SECTOR_SHIFT;
> +	zone_info->zone_size_shift = ilog2(zone_info->zone_size);
> +	zone_info->nr_zones = nr_sectors >> ilog2(bdev_zone_sectors(bdev));
> +	if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
> +		zone_info->nr_zones++;
> +
> +	zone_info->seq_zones = kcalloc(BITS_TO_LONGS(zone_info->nr_zones),
> +				       sizeof(*zone_info->seq_zones),
> +				       GFP_KERNEL);
> +	if (!zone_info->seq_zones) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	zone_info->empty_zones = kcalloc(BITS_TO_LONGS(zone_info->nr_zones),
> +					 sizeof(*zone_info->empty_zones),
> +					 GFP_KERNEL);
> +	if (!zone_info->empty_zones) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +
> +	zones = kcalloc(BTRFS_REPORT_NR_ZONES,
> +			sizeof(struct blk_zone), GFP_KERNEL);
> +	if (!zones)
> +		return -ENOMEM;

Won't this will leak zone_info, zone_info->seq_zones and
zone_info->empty_zones.


[...]

> +out:
> +	kfree(zones);
> +
> +	if (ret) {
> +		kfree(zone_info->seq_zones);
> +		kfree(zone_info->empty_zones);
> +		kfree(zone_info);
> +	}

Which is why I think it would be more clear to have:
free_zones:
	kfree(zones);
free_zi_emp_zones:
	kfree(zone_info->empty_zones);
free_zi_seq_zones:
	kfree(zone_info->seq_zones);
free_zi:
	kfree(zone_info);



-- 
Johannes Thumshirn                            SUSE Labs Filesystems
jthumshirn@suse.de                                +49 911 74053 689
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