Xuan Zhuo
2023-Apr-27 03:05 UTC
[PATCH net-next v4 12/15] virtio_net: small: avoid double counting in xdp scenarios
Avoid the problem that some variables(headroom and so on) will repeat the calculation when process xdp. Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> Acked-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index b8ec642899c9..f832ab8a3e6e 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1027,11 +1027,10 @@ static struct sk_buff *receive_small(struct net_device *dev, struct sk_buff *skb; struct bpf_prog *xdp_prog; unsigned int xdp_headroom = (unsigned long)ctx; - unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom; - unsigned int headroom = vi->hdr_len + header_offset; - unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) + - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); struct page *page = virt_to_head_page(buf); + unsigned int header_offset; + unsigned int headroom; + unsigned int buflen; len -= vi->hdr_len; stats->bytes += len; @@ -1059,6 +1058,11 @@ static struct sk_buff *receive_small(struct net_device *dev, rcu_read_unlock(); skip_xdp: + header_offset = VIRTNET_RX_PAD + xdp_headroom; + headroom = vi->hdr_len + header_offset; + buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + skb = build_skb(buf, buflen); if (!skb) goto err; -- 2.32.0.3.g01195cf9f
Michael S. Tsirkin
2023-Apr-28 01:08 UTC
[PATCH net-next v4 12/15] virtio_net: small: avoid double counting in xdp scenarios
On Thu, Apr 27, 2023 at 11:05:31AM +0800, Xuan Zhuo wrote:> Avoid the problem that some variables(headroom and so on) will repeat > the calculation when process xdp. > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > Acked-by: Jason Wang <jasowang at redhat.com>this is "code duplication" not "double counting".> --- > drivers/net/virtio_net.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index b8ec642899c9..f832ab8a3e6e 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1027,11 +1027,10 @@ static struct sk_buff *receive_small(struct net_device *dev, > struct sk_buff *skb; > struct bpf_prog *xdp_prog; > unsigned int xdp_headroom = (unsigned long)ctx; > - unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom; > - unsigned int headroom = vi->hdr_len + header_offset; > - unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) + > - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > struct page *page = virt_to_head_page(buf); > + unsigned int header_offset; > + unsigned int headroom; > + unsigned int buflen; > > len -= vi->hdr_len; > stats->bytes += len; > @@ -1059,6 +1058,11 @@ static struct sk_buff *receive_small(struct net_device *dev, > rcu_read_unlock(); > > skip_xdp: > + header_offset = VIRTNET_RX_PAD + xdp_headroom; > + headroom = vi->hdr_len + header_offset; > + buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) + > + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > + > skb = build_skb(buf, buflen); > if (!skb) > goto err; > -- > 2.32.0.3.g01195cf9f