Re: [PATCH 6/7] dm-zone: use generic helpers to calculate offset from zone start

[Pankaj Raghav]

On 2023-01-10 07:57, Christoph Hellwig wrote:
> On Fri, Jan 06, 2023 at 09:33:16AM +0100, Pankaj Raghav wrote:
>> Use the bdev_offset_from_zone_start() helper function to calculate
>> the offset from zone start instead of open coding.
>>
>> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
>> Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
>> Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
>> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
>> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
>> Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
>> ---
>>  drivers/md/dm-zone.c | 8 +++-----
>>  1 file changed, 3 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c
>> index 3dafc0e8b7a9..ac6fc1293d41 100644
>> --- a/drivers/md/dm-zone.c
>> +++ b/drivers/md/dm-zone.c
>> @@ -390,7 +390,8 @@ static bool dm_zone_map_bio_begin(struct mapped_device *md,
>>  	case REQ_OP_WRITE_ZEROES:
>>  	case REQ_OP_WRITE:
>>  		/* Writes must be aligned to the zone write pointer */
>> -		if ((clone->bi_iter.bi_sector & (zsectors - 1)) != zwp_offset)
>> +		if (bdev_offset_from_zone_start(md->disk->part0,
>> +						clone->bi_iter.bi_sector) != zwp_offset)
> 
> I can't see how this actually cleans antyhing up, while it does add an
> overly long line.
>
While I do agree with the overly long line comment, I feel it makes the
intent more clear, as it is easy to overlook this math operation.

>>  		if (clone->bi_status == BLK_STS_OK &&
>>  		    bio_op(clone) == REQ_OP_ZONE_APPEND) {
>>  			orig_bio->bi_iter.bi_sector +=
>> -				clone->bi_iter.bi_sector & mask;
>> +				bdev_offset_from_zone_start(disk->part0, clone->bi_iter.bi_sector);
> 
> Same here.