Shaun Tancheff <shaun.tancheff@xxxxxxxxxxx> writes:
> On Tue, Oct 18, 2016 at 11:58 AM, Jeff Moyer <jmoyer@xxxxxxxxxx> wrote:
>> Damien Le Moal <damien.lemoal@xxxxxxx> writes:
>>
>>> + if (!is_power_of_2(zone_blocks)) {
>>> + if (sdkp->first_scan)
>>> + sd_printk(KERN_NOTICE, sdkp,
>>> + "Devices with non power of 2 zone "
>>> + "size are not supported\n");
>>> + return -ENODEV;
>>> + }
>>
>> Are power of 2 zone sizes required by the standard? I see why you've
>> done this, but I wonder if we're artificially limiting the
>> implementation, and whether there will be valid devices on the market
>> that simply won't work with Linux because of this.
>
> The standard does not require power of 2 zones.
> That said, I am not aware of any current (or planned) devices other
> than a power of 2.
> Common zone sizes I am aware of: 256MiB, 128MiB and 1GiB.
>
> Also note that we are excluding the runt zone from the power of 2 expectation.
>
> So conforming devices should (excluding a runt zone):
> - Have zones of the same size.
> - Choose a zone size that is a power of 2.
OK, thanks for following up. As long as the drive vendors are on board,
I guess we're okay. :)
-Jeff
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