Re: [PATCH net] virtio-net: unbreak cusmed packet for small buffer XDP

[Jason Wang]

On 2017å06æ28æ 10:02, Michael S. Tsirkin wrote:
> On Wed, Jun 28, 2017 at 09:54:03AM +0800, Jason Wang wrote:
> > We should allow csumed packet for small buffer, otherwise XDP_PASS
> > won't work correctly.
> >
> > Fixes commit bb91accf2733 ("virtio-net: XDP support for small buffers")
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> The issue would be VIRTIO_NET_HDR_F_DATA_VALID might be set.
> What do you think?

I think it's safe. For XDP_PASS, it work like in the past. For XDP_TX, 
we zero the vnet header. For adjusting header, XDP prog should deal with 
csum.

Thanks

> > ---
> > The patch is needed for -stable.
> > ---
> >   drivers/net/virtio_net.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 143d8a9..499fcc9 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -413,7 +413,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
> >   		void *orig_data;
> >   		u32 act;
> >   
> > -		if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
> > +		if (unlikely(hdr->hdr.gso_type))
> >   			goto err_xdp;
> >   
> >   		xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len;
> > --
> > 2.7.4