Re: [Qemu-devel] [Xen-devel] [PATCH v2] xen: fix qdisk BLKIF_OP_DISCARD for 32/64 word size mix

[Juergen Gross]

On 17/06/16 11:26, Jan Beulich wrote:
>>>> On 17.06.16 at 11:14, <address@hidden> wrote:
>> In case the word size of the domU and qemu running the qdisk backend
>> differ BLKIF_OP_DISCARD will not work reliably, as the request
>> structure in the ring have different layouts for different word size.
>>
>> Correct this by copying the request structure in case of different
>> word size element by element in the BLKIF_OP_DISCARD case, too.
>>
>> The easiest way to achieve this is to resync hw/block/xen_blkif.h with
>> its original source from the Linux kernel.
>>
>> Signed-off-by: Juergen Gross <address@hidden>
>> ---
>> V2: resync with Linux kernel version of hw/block/xen_blkif.h as
>>     suggested by Paul Durrant
> 
> Oh, I didn't realize he suggested syncing with the Linux variant.
> Why not with the canonical one? I have to admit that I particularly
> dislike Linux'es strange union-izng, mainly because of it requiring
> this myriad of __attribute__((__packed__)).

What would be gained by syncing with the canonical one? The part to be
modified is available in the Linux variant only.


Juergen