On Fri, Jul 8, 2016 at 5:15 AM, Brenden Blanco <bbla...@plumgrid.com> wrote:
> Add support for the BPF_PROG_TYPE_XDP hook in mlx4 driver.
>
> In tc/socket bpf programs, helpers linearize skb fragments as needed
> when the program touchs the packet data. However, in the pursuit of
nit, for the next version touchs --> touches
> speed, XDP programs will not be allowed to use these slower functions,
> especially if it involves allocating an skb.
[...]
> @@ -835,6 +838,34 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct
> mlx4_en_cq *cq, int bud
> l2_tunnel = (dev->hw_enc_features & NETIF_F_RXCSUM) &&
> (cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_L2_TUNNEL));
>
> + /* A bpf program gets first chance to drop the packet. It may
> + * read bytes but not past the end of the frag.
> + */
> + if (prog) {
> + struct xdp_buff xdp;
> + dma_addr_t dma;
> + u32 act;
> +
> + dma = be64_to_cpu(rx_desc->data[0].addr);
> + dma_sync_single_for_cpu(priv->ddev, dma,
> + priv->frag_info[0].frag_size,
> + DMA_FROM_DEVICE);
> +
> + xdp.data = page_address(frags[0].page) +
> + frags[0].page_offset;
> + xdp.data_end = xdp.data + length;
> +
> + act = bpf_prog_run_xdp(prog, &xdp);
> + switch (act) {
> + case XDP_PASS:
> + break;
> + default:
> + bpf_warn_invalid_xdp_action(act);
> + case XDP_DROP:
> + goto next;
> + }
> + }
(probably a nit too, but wanted to make sure we don't miss something
here) is the default case preceding the DROP one in purpose? any
special reason to do that?
