Re: [Qemu-block] [PATCH v2 15/17] block: Switch discard length bounds to byte-based

[Eric Blake]

On 06/21/2016 08:05 AM, Kevin Wolf wrote:
> Am 14.06.2016 um 23:30 hat Eric Blake geschrieben:
>> Sector-based limits are awkward to think about; in our on-going
>> quest to move to byte-based interfaces, convert max_discard and
>> discard_alignment.  Rename them, using 'pdiscard' as an aid to
>> track which remaining discard interfaces need conversion, and so
>> that the compiler will help us catch the change in semantics
>> across any rebased code.  In iscsi.c, sector_limits_lun2qemu()
>> is no longer needed; and the BlockLimits type is now completely
>> byte-based.
>>
>> Signed-off-by: Eric Blake <address@hidden>
> 
>>      /* maximum number of bytes that can zeroized at once (since it is
>> -     * signed, it must be < 2G, if set) */
>> +     * signed, it must be < 2G, if set), should be multiple of
>> +     * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
>>      int32_t max_pwrite_zeroes;
>>
>>      /* optimal alignment for write zeroes requests in bytes, must be
>> -     * power of 2, and less than max_pwrite_zeroes if that is set */
>> +     * power of 2, less than max_pwrite_zeroes if that is set, and
>> +     * multiple of bs->request_alignment. May be 0 if
>> +     * bs->request_alignment is good enough */
>>      uint32_t pwrite_zeroes_alignment;
> 
> I think you intended to have these as part of some earlier patch, they
> are not related to discard.

Well, the patch they should have been in is already part of master
(cf081fca), so I'll just split out the changes to a trivial prereq patch.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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