Re: [PATCH net-next v2 20/33] vhost_net: also populate XDP frame size

Jason Wang
2020-05-06T06:50:20Z

On 2020/5/6 下午2:41, Jason Wang wrote:
>
> On 2020/4/30 下午7:22, Jesper Dangaard Brouer wrote:
>> In vhost_net_build_xdp() the 'buf' that gets queued via an xdp_buff
>> have embedded a struct tun_xdp_hdr (located at xdp->data_hard_start)
>> which contains the buffer length 'buflen' (with tailroom for
>> skb_shared_info). Also storing this buflen in xdp->frame_sz, does not
>> obsolete struct tun_xdp_hdr, as it also contains a struct
>> virtio_net_hdr with other information.
>>
>> Cc: Jason Wang <jasowang@redhat.com>
>> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
>> ---
>>   drivers/vhost/net.c |    1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
>> index 2927f02cc7e1..516519dcc8ff 100644
>> --- a/drivers/vhost/net.c
>> +++ b/drivers/vhost/net.c
>> @@ -747,6 +747,7 @@ static int vhost_net_build_xdp(struct
>> vhost_net_virtqueue *nvq,
>>       xdp->data = buf + pad;
>>       xdp->data_end = xdp->data + len;
>>       hdr->buflen = buflen;
>> +    xdp->frame_sz = buflen;
>>         --net->refcnt_bias;
>>       alloc_frag->offset += buflen;
>
>
> Hi Jesper:
>
> As I said in v1, tun will do this for us (patch 19) via hdr->buflen.
> So it looks to me this is not necessary?
>
> Thanks

Miss your reply. So

Acked-by: Jason Wang <jasowang@redhat.com>