On Tue, Apr 18, 2023 at 2:53 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> virtnet_xdp_handler() is to process all the logic related to XDP. The
> caller only needs to care about how to deal with the buf. So this commit
> introduces new enums:
>
> 1. VIRTNET_XDP_RES_PASS: make skb by the buf
> 2. VIRTNET_XDP_RES_DROP: xdp return drop action or some error, caller
> should release the buf
> 3. VIRTNET_XDP_RES_CONSUMED: xdp consumed the buf, the caller doesnot to
Typo, should be "does not"
> do anything
>
I think it's better if you could explain if this can help anything
(e.g simplify the patches on top?).
Thanks
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 42 ++++++++++++++++++++++++++--------------
> 1 file changed, 27 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0fa64c314ea7..4dfdc211d355 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -301,6 +301,15 @@ struct padded_vnet_hdr {
> char padding[12];
> };
>
> +enum {
> + /* xdp pass */
> + VIRTNET_XDP_RES_PASS,
> + /* drop packet. the caller needs to release the page. */
> + VIRTNET_XDP_RES_DROP,
> + /* packet is consumed by xdp. the caller needs to do nothing. */
> + VIRTNET_XDP_RES_CONSUMED,
> +};
> +
> static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
> static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
>
> @@ -803,14 +812,14 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
>
> switch (act) {
> case XDP_PASS:
> - return act;
> + return VIRTNET_XDP_RES_PASS;
>
> case XDP_TX:
> stats->xdp_tx++;
> xdpf = xdp_convert_buff_to_frame(xdp);
> if (unlikely(!xdpf)) {
> netdev_dbg(dev, "convert buff to frame failed for xdp\n");
> - return XDP_DROP;
> + return VIRTNET_XDP_RES_DROP;
> }
>
> err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
> @@ -818,19 +827,20 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> xdp_return_frame_rx_napi(xdpf);
> } else if (unlikely(err < 0)) {
> trace_xdp_exception(dev, xdp_prog, act);
> - return XDP_DROP;
> + return VIRTNET_XDP_RES_DROP;
> }
> +
> *xdp_xmit |= VIRTIO_XDP_TX;
> - return act;
> + return VIRTNET_XDP_RES_CONSUMED;
>
> case XDP_REDIRECT:
> stats->xdp_redirects++;
> err = xdp_do_redirect(dev, xdp, xdp_prog);
> if (err)
> - return XDP_DROP;
> + return VIRTNET_XDP_RES_DROP;
>
> *xdp_xmit |= VIRTIO_XDP_REDIR;
> - return act;
> + return VIRTNET_XDP_RES_CONSUMED;
>
> default:
> bpf_warn_invalid_xdp_action(dev, xdp_prog, act);
> @@ -839,7 +849,7 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> trace_xdp_exception(dev, xdp_prog, act);
> fallthrough;
> case XDP_DROP:
> - return XDP_DROP;
> + return VIRTNET_XDP_RES_DROP;
> }
> }
>
> @@ -987,17 +997,18 @@ static struct sk_buff *receive_small(struct net_device *dev,
> act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
>
> switch (act) {
> - case XDP_PASS:
> + case VIRTNET_XDP_RES_PASS:
> /* Recalculate length in case bpf program changed it */
> delta = orig_data - xdp.data;
> len = xdp.data_end - xdp.data;
> metasize = xdp.data - xdp.data_meta;
> break;
> - case XDP_TX:
> - case XDP_REDIRECT:
> +
> + case VIRTNET_XDP_RES_CONSUMED:
> rcu_read_unlock();
> goto xdp_xmit;
> - default:
> +
> + case VIRTNET_XDP_RES_DROP:
> goto err_xdp;
> }
> }
> @@ -1324,18 +1335,19 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
>
> switch (act) {
> - case XDP_PASS:
> + case VIRTNET_XDP_RES_PASS:
> head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
> if (unlikely(!head_skb))
> goto err_xdp_frags;
>
> rcu_read_unlock();
> return head_skb;
> - case XDP_TX:
> - case XDP_REDIRECT:
> +
> + case VIRTNET_XDP_RES_CONSUMED:
> rcu_read_unlock();
> goto xdp_xmit;
> - default:
> +
> + case VIRTNET_XDP_RES_DROP:
> break;
> }
> err_xdp_frags:
> --
> 2.32.0.3.g01195cf9f
>
