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

[Naohiro Aota]

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
jthumsh...@suse.de                                +49 911 74053 689
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