But yeah if it has unmap granularity reported to be, for example, 16,
then it will not be correctly set with min_not_zero().
Wait, shouldn't it be:
max(sdkp->logical_block_size,
sdkp->unmap_granularity * logical_block_size);
then?
On 12 March 2016 at 13:37, Tom Yan <tom.ty89@xxxxxxxxx> wrote:
> Suppose a device has logical block size of 512 bytes and physical
> block size of 4096 bytes ("AF 512e").
>
> If it has unmap granularity reported to be 1, then its discard
> granularity should be 1 * 512 = 512 bytes. However, with max() it is
> set to 4096 bytes instead. With min_not_zero(), it is CORRECTLY set to
> 512 bytes.
>
> If it does not has unmap granularity reported, then with max() its
> discard granularity is set to 4096 bytes. But with min_not_zero(), it
> will ALSO be set to 4096 bytes.
>
> Therefore, I don't see why max() should be used instead according to
> your previous mails.
>
> On 12 March 2016 at 05:41, Martin K. Petersen
> <martin.petersen@xxxxxxxxxx> wrote:
>>>>>>> "Tom" == Tom Yan <tom.ty89@xxxxxxxxx> writes:
>>
>> Tom,
>>
>> Tom> Would min_not_zero() be more proper than max()?
>>
>> That would effectively set discard_granularity to physical_block_size
>> regardless of whether unmap_granularity was provided or not.
>>
>> --
>> Martin K. Petersen Oracle Linux Engineering
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
