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Date:   Thu, 16 Jun 2022 09:04:48 -0700
From:   Luis Chamberlain <mcgrof@kernel.org>
To:     Pankaj Raghav <p.raghav@samsung.com>
Cc:     Bart Van Assche <bvanassche@acm.org>, hch@lst.de,
        snitzer@redhat.com, damien.lemoal@opensource.wdc.com,
        axboe@kernel.dk, pankydev8@gmail.com, gost.dev@samsung.com,
        jiangbo.365@bytedance.com, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        dm-devel@redhat.com, jonathan.derrick@linux.dev,
        Johannes.Thumshirn@wdc.com, dsterba@suse.com, jaegeuk@kernel.org
Subject: Re: [dm-devel] [PATCH v7 02/13] block: allow blk-zoned devices to
 have non-power-of-2 zone size
Message-ID: <YqtUoK4KzvG7NQS0@bombadil.infradead.org>
References: <20220615101920.329421-1-p.raghav@samsung.com>
 <CGME20220615101931eucas1p15ed09ae433a2c378b599e9086130d8eb@eucas1p1.samsung.com>
 <20220615101920.329421-3-p.raghav@samsung.com>
 <857c444a-02b9-9cef-0c5b-2ecdb2fd46f6@acm.org>
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On Thu, Jun 16, 2022 at 12:09:35PM +0200, Pankaj Raghav wrote:
> On 2022-06-15 22:28, Bart Van Assche wrote:
> >> +??????? if (!is_power_of_2(zone->len) && zone->capacity < zone->len) {
> >> +??????????? pr_warn("%s: Invalid zone capacity for non power of 2
> >> zone size",
> >> +??????????????? disk->disk_name);
> >> ????????????? return -ENODEV;
> >> ????????? }
> > 
> > The above check seems wrong to me. I don't see why devices that report a
> > capacity that is less than the zone size should be rejected.
> > 
> This was brought up by Damien during previous reviews. The argument was
> that the reason to allow non power-of-2 zoned device is to remove the
> gaps between zone size and zone capacity. Allowing a npo2 zone size with
> a different capacity, even though it is technically possible, it does
> not make any practical sense. That is why this check was introduced.
> Does that answer your question?

Perhaps just add a comment because unless you are involved in the prior
reviews this might not be clear.

  Luis