linux-kernel - Re: [PATCH v8 02/11] block: allow blk-zoned devices to have non-power-of-2 zone size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <514f85ce-84fc-1186-7169-a29d7118e8cc@acm.org>
Date:   Thu, 28 Jul 2022 06:29:09 -0700
From:   Bart Van Assche <bvanassche@....org>
To:     Pankaj Raghav <p.raghav@...sung.com>,
        damien.lemoal@...nsource.wdc.com, hch@....de, axboe@...nel.dk,
        snitzer@...nel.org, Johannes.Thumshirn@....com
Cc:     matias.bjorling@....com, gost.dev@...sung.com,
        linux-kernel@...r.kernel.org, hare@...e.de,
        linux-block@...r.kernel.org, pankydev8@...il.com,
        jaegeuk@...nel.org, dm-devel@...hat.com,
        linux-nvme@...ts.infradead.org,
        Luis Chamberlain <mcgrof@...nel.org>
Subject: Re: [PATCH v8 02/11] block: allow blk-zoned devices to have
 non-power-of-2 zone size

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.