Re: [Intel-wired-lan] [PATCH iwl-next] virtchnl: fix m68k build.

[Paolo Abeni <pabeni@redhat.com>]

On 10/17/24 00:49, Jacob Keller wrote:
> On 10/15/2024 6:56 AM, Paolo Abeni wrote:
>> The kernel test robot reported a build failure on m68k in the intel
>> driver due to the recent shapers-related changes.
>>
>> The mentioned arch has funny alignment properties, let's be explicit
>> about the binary layout expectation introducing a padding field.
>>
>> Fixes: 608a5c05c39b ("virtchnl: support queue rate limit and quanta size configuration")
>> Reported-by: kernel test robot <lkp@intel.com>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202410131710.71Wt6LKO-lkp@intel.com/
>> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
>> ---
>>   include/linux/avf/virtchnl.h | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h
>> index 223e433c39fe..13a11f3c09b8 100644
>> --- a/include/linux/avf/virtchnl.h
>> +++ b/include/linux/avf/virtchnl.h
>> @@ -1499,6 +1499,7 @@ VIRTCHNL_CHECK_STRUCT_LEN(8, virtchnl_queue_chunk);
>>   
>>   struct virtchnl_quanta_cfg {
>>   	u16 quanta_size;
>> +	u16 pad;
>>   	struct virtchnl_queue_chunk queue_select;
> 
> There's a hidden 2 byte padding because queue_select requires 4-byte
> alignment. We assume this, as the VIRTCHNL_CHECK_STRUCT_LEN for this
> structure is 12 bytes.
> 
> On mk68k, we must not be adding this padding, which results in a 10 byte
> structure, failing the size check for VIRTCHNL_CHECK_STRUCT_LEN,
> resulting in the compilation error?

Exactly!

> Adding the explicit size aligns with the actual expected layout and size
> for this structure, fixing mk68k without affecting the other architectures.
> 
> Ok.
> 
> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

Thanks,

Please LMK if you prefer/agree to have this one applied directly on 
net-next, to reduce build issues spawning around ASAP.

Paolo