On Sun, Apr 23, 2023 at 6:57 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> virtnet_build_xdp_buff_mrg() and virtnet_xdp_handler() auto
> release xdp shinfo then the caller no need to careful the xdp shinfo.
Thinking of this, I think releasing frags in
virtnet_build_xdp_buff_mrg() is fine. But for virtnet_xdp_handler(),
it's better to be done by the caller, since the frags were prepared by
the caller anyhow.
Thanks
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 29 +++++++++++++++++------------
> 1 file changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 5f37a1cef61e..c6bf425e8844 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -825,7 +825,7 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> xdpf = xdp_convert_buff_to_frame(xdp);
> if (unlikely(!xdpf)) {
> netdev_dbg(dev, "convert buff to frame failed for xdp\n");
> - return XDP_DROP;
> + goto drop;
> }
>
> err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
> @@ -833,7 +833,7 @@ 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;
> + goto drop;
> }
> *xdp_xmit |= VIRTIO_XDP_TX;
> return act;
> @@ -842,7 +842,7 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> stats->xdp_redirects++;
> err = xdp_do_redirect(dev, xdp, xdp_prog);
> if (err)
> - return XDP_DROP;
> + goto drop;
>
> *xdp_xmit |= VIRTIO_XDP_REDIR;
> return act;
> @@ -854,8 +854,12 @@ 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;
> + break;
> }
> +
> +drop:
> + put_xdp_frags(xdp);
> + return XDP_DROP;
> }
>
> static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
> @@ -1190,7 +1194,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
> dev->name, *num_buf,
> virtio16_to_cpu(vi->vdev, hdr->num_buffers));
> dev->stats.rx_length_errors++;
> - return -EINVAL;
> + goto err;
> }
>
> stats->bytes += len;
> @@ -1209,7 +1213,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
> pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
> dev->name, len, (unsigned long)(truesize - room));
> dev->stats.rx_length_errors++;
> - return -EINVAL;
> + goto err;
> }
>
> frag = &shinfo->frags[shinfo->nr_frags++];
> @@ -1224,6 +1228,10 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>
> *xdp_frags_truesize = xdp_frags_truesz;
> return 0;
> +
> +err:
> + put_xdp_frags(xdp);
> + return -EINVAL;
> }
>
> static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
> @@ -1353,7 +1361,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
> &num_buf, &xdp_frags_truesz, stats);
> if (unlikely(err))
> - goto err_xdp_frags;
> + goto err_xdp;
>
> act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
>
> @@ -1361,7 +1369,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> case XDP_PASS:
> head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
> if (unlikely(!head_skb))
> - goto err_xdp_frags;
> + goto err_xdp;
>
> rcu_read_unlock();
> return head_skb;
> @@ -1370,11 +1378,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> rcu_read_unlock();
> goto xdp_xmit;
> default:
> - break;
> + goto err_xdp;
> }
> -err_xdp_frags:
> - put_xdp_frags(&xdp);
> - goto err_xdp;
> }
> rcu_read_unlock();
>
> --
> 2.32.0.3.g01195cf9f
>
