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Date:   Tue, 10 Jan 2023 10:06:21 +0100
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Subject: Re: [PATCH 6/7] dm-zone: use generic helpers to calculate offset
 from zone start
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To:     Christoph Hellwig <hch@lst.de>
CC:     <axboe@kernel.dk>, <kernel@pankajraghav.com>,
        <linux-kernel@vger.kernel.org>, <hare@suse.de>,
        <bvanassche@acm.org>, <snitzer@kernel.org>, <dm-devel@redhat.com>,
        <damien.lemoal@opensource.wdc.com>,
        <linux-nvme@lists.infradead.org>, <linux-block@vger.kernel.org>,
        <gost.dev@samsung.com>, Luis Chamberlain <mcgrof@kernel.org>,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>
From:   Pankaj Raghav <p.raghav@samsung.com>
In-Reply-To: <20230110065738.GE10289@lst.de>
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References: <20230106083317.93938-1-p.raghav@samsung.com>
        <CGME20230106083322eucas1p1ce3ca7b02ca87bb2be8543291e223338@eucas1p1.samsung.com>
        <20230106083317.93938-7-p.raghav@samsung.com>
        <20230110065738.GE10289@lst.de>
Precedence: bulk

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@samsung.com>
>> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
>> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
>> Reviewed-by: Bart Van Assche <bvanassche@acm.org>
>> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>> Reviewed-by: Mike Snitzer <snitzer@kernel.org>
>> ---
>>  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.