Re: [PATCH net-next v6 09/10] virtio_net: xsk: rx: support recv merge mode

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

On Thu, 20 Jun 2024 12:37:43 +0200, Paolo Abeni <pabeni@redhat.com> wrote:
> On Tue, 2024-06-18 at 15:56 +0800, Xuan Zhuo wrote:
> > Support AF-XDP for merge mode.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> >  drivers/net/virtio_net.c | 139 +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 139 insertions(+)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 06608d696e2e..cfa106aa8039 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -504,6 +504,10 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> >  			       struct net_device *dev,
> >  			       unsigned int *xdp_xmit,
> >  			       struct virtnet_rq_stats *stats);
> > +static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
> > +					       struct sk_buff *curr_skb,
> > +					       struct page *page, void *buf,
> > +					       int len, int truesize);
> >
> >  static bool is_xdp_frame(void *ptr)
> >  {
> > @@ -1128,6 +1132,139 @@ static struct sk_buff *virtnet_receive_xsk_small(struct net_device *dev, struct
> >  	}
> >  }
> >
> > +static void xsk_drop_follow_bufs(struct net_device *dev,
> > +				 struct receive_queue *rq,
> > +				 u32 num_buf,
> > +				 struct virtnet_rq_stats *stats)
> > +{
> > +	struct xdp_buff *xdp;
> > +	u32 len;
> > +
> > +	while (num_buf-- > 1) {
>
> Why do you skip the last buffer? I thought it should be dropped, too?!?


Here, we just need to drop the follow bufs (num_buf - 1). The first one have be
dropped.

Thanks.


>
> Thanks!
>
> Paolo
>