[PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP
From: Jason Wang <jasowang@redhat.com>
Date: 2020-05-06 06:16:51
Also in:
bpf, lkml, virtualization
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve space for vnet header in this case. Cc: Jesper Dangaard Brouer <redacted> Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 11f722460513..98dd75b665a5 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -684,8 +684,8 @@ static struct sk_buff *receive_small(struct net_device *dev, page = xdp_page; } - xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len; - xdp.data = xdp.data_hard_start + xdp_headroom; + xdp.data_hard_start = buf + VIRTNET_RX_PAD; + xdp.data = xdp.data_hard_start + xdp_headroom + vi->hdr_len; xdp.data_end = xdp.data + len; xdp.data_meta = xdp.data; xdp.rxq = &rq->xdp_rxq;
@@ -845,7 +845,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, * the descriptor on if we get an XDP_TX return code. */ data = page_address(xdp_page) + offset; - xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM + vi->hdr_len; + xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM; xdp.data = data + vi->hdr_len; xdp.data_end = xdp.data + (len - vi->hdr_len); xdp.data_meta = xdp.data;
--
2.20.1