Re: [PATCH bpf-next v4] virtio_net: add XDP meta data support

[Yuya Kusakabe]

On 2/5/20 2:33 PM, Michael S. Tsirkin wrote:
> On Tue, Feb 04, 2020 at 04:16:55PM +0900, Yuya Kusakabe wrote:
>> @@ -852,8 +868,9 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>  			 * adjustments. Note other cases do not build an
>>  			 * skb and avoid using offset
>>  			 */
>> -			offset = xdp.data -
>> -					page_address(xdp_page) - vi->hdr_len;
>> +			metasize = xdp.data - xdp.data_meta;
>> +			offset = xdp.data - page_address(xdp_page) -
>> +				 vi->hdr_len - metasize;
>>  
>>  			/* recalculate len if xdp.data or xdp.data_end were
>>  			 * adjusted
> 
> Tricky to get one's head around.
> Can you pls update the comment above to document the new math?
> 

Thank you for your review.

I will update the comment on next patch.