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

On 2020/5/6 下午2:41, Jason Wang wrote:

On 2020/4/30 下午7:22, Jesper Dangaard Brouer wrote:

quoted

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 <redacted>
Signed-off-by: Jesper Dangaard Brouer <redacted>
---
  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 <redacted>