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

[Naohiro Aota <naohiro.aota@xxxxxxx>]

On Fri, Aug 23, 2019 at 01:57:33PM +0200, Johannes Thumshirn wrote:
> 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.

Ah, yes. I'll fix that using the suggested style below.

Thanks

> [...]
>
> > +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@xxxxxxx                                +49 911 74053 689
> SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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> HRB 21284 (AG Nürnberg)
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