Re: [PATCH 1/2] block: introduce zone capacity helper

[Naohiro Aota <Naohiro.Aota@wdc.com>]

On Wed Mar 12, 2025 at 10:39 AM JST, Damien Le Moal wrote:
> On 3/12/25 10:31, Naohiro Aota wrote:
>> {bdev,disk}_zone_capacity() takes block_device or gendisk and sector position
>> and returns the zone capacity of the corresponding zone.
>> 
>> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
>> ---
>>  include/linux/blkdev.h | 21 +++++++++++++++++++++
>>  1 file changed, 21 insertions(+)
>> 
>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>> index d37751789bf5..3c860a0cf339 100644
>> --- a/include/linux/blkdev.h
>> +++ b/include/linux/blkdev.h
>> @@ -826,6 +826,27 @@ static inline u64 sb_bdev_nr_blocks(struct super_block *sb)
>>  		(sb->s_blocksize_bits - SECTOR_SHIFT);
>>  }
>>  
>> +#ifdef CONFIG_BLK_DEV_ZONED
>
> There is already an "#ifdef CONFIG_BLK_DEV_ZONED" in blkdev.h, see
> disk_nr_zones(). Please add this new helper under that ifdef to avoid adding a
> new one.

Sure. But, since this patch uses get_capacity(), we need to move the
existing ones here instead.

>
>> +static inline unsigned int disk_zone_capacity(struct gendisk *disk, sector_t pos)
>> +{
>> +	sector_t zone_sectors = disk->queue->limits.chunk_sectors;
>> +
>> +	if (pos + zone_sectors >= get_capacity(disk))
>> +		return disk->last_zone_capacity;
>> +	return disk->zone_capacity;
>> +}
>> +#else /* CONFIG_BLK_DEV_ZONED */
>> +static inline unsigned int disk_zone_capacity(struct gendisk *disk, sector_t pos)
>
> Is this ever called for a non zoned drive ? It should not be... So do we really
> need this stub ?

I added that just let it compile without CONFIG_BLK_DEV_ZONED. Well, the code
querying the capacity should be under CONFIG_BLK_DEV_ZONED, so maybe it
is not necessary. I'll drop that.

>
>> +{
>> +	return 0;
>> +}
>> +#endif /* CONFIG_BLK_DEV_ZONED */
>> +
>> +static inline unsigned int bdev_zone_capacity(struct block_device *bdev, sector_t pos)
>> +{
>> +	return disk_zone_capacity(bdev->bd_disk, pos);
>> +}
>> +
>>  int bdev_disk_changed(struct gendisk *disk, bool invalidate);
>>  
>>  void put_disk(struct gendisk *disk);