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Date:   Thu, 28 Jul 2022 06:29:09 -0700
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Subject: Re: [PATCH v8 02/11] block: allow blk-zoned devices to have
 non-power-of-2 zone size
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To:     Pankaj Raghav <p.raghav@samsung.com>,
        damien.lemoal@opensource.wdc.com, hch@lst.de, axboe@kernel.dk,
        snitzer@kernel.org, Johannes.Thumshirn@wdc.com
Cc:     matias.bjorling@wdc.com, gost.dev@samsung.com,
        linux-kernel@vger.kernel.org, hare@suse.de,
        linux-block@vger.kernel.org, pankydev8@gmail.com,
        jaegeuk@kernel.org, dm-devel@redhat.com,
        linux-nvme@lists.infradead.org,
        Luis Chamberlain <mcgrof@kernel.org>
References: <20220727162245.209794-1-p.raghav@samsung.com>
 <CGME20220727162248eucas1p2ff8c3c2b021bedcae3960024b4e269e9@eucas1p2.samsung.com>
 <20220727162245.209794-3-p.raghav@samsung.com>
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 <eed7d9ee-fd7f-e57c-598e-909dbb0d2380@samsung.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <eed7d9ee-fd7f-e57c-598e-909dbb0d2380@samsung.com>
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On 7/28/22 05:11, Pankaj Raghav wrote:
> On 2022-07-28 01:16, Bart Van Assche wrote:
>> The bdev_is_zone_start() name seems more clear to me than
>> bdev_is_zone_aligned(). Has there already been a discussion about which
>> name to use for this function?
>>
> The reason I did s/bdev_is_zone_start/bdev_is_zone_aligned is that this
> name makes more sense for also checking if a given size is a multiple of
> zone sectors for e.g., used in PATCH 9:
> 
> -		if (len & (zone_sectors - 1)) {
> +		if (!bdev_is_zone_aligned(bdev, len)) {
> 
> I felt `bdev_is_zone_aligned` fits the use case of checking if the
> sector starts at the start of a zone and also check if a given length of
> sectors also align with the zone sectors. bdev_is_zone_start does not
> make the intention clear for the latter use case IMO.
> 
> But I am fine with going back to bdev_is_zone_start if you and Damien
> feel strongly otherwise.
The "zone start LBA" terminology occurs in ZBC-1, ZBC-2 and ZNS but 
"zone aligned" not. I prefer "zone start" because it is clear, 
unambiguous and because it has the same meaning as in the corresponding 
standards documents. I propose to proceed as follows for checking 
whether a number of LBAs is a multiple of the zone length:
* Either use bdev_is_zone_start() directly.
* Or introduce a synonym for bdev_is_zone_start() with an appropriate 
name, e.g. bdev_is_zone_len_multiple().

Thanks,

Bart.