On Sat, Aug 27, 2016 at 10:11 AM, John Fastabend
<john.fastab...@gmail.com> wrote:
> From: Alexei Starovoitov <a...@fb.com>
> This patch adds initial support for XDP on e1000 driver. Note e1000
> driver does not support page recycling in general which could be
> added as a further improvement. However for XDP_DROP and XDP_XMIT
> the xdp code paths will recycle pages.
> @@ -4188,15 +4305,57 @@ static bool e1000_clean_jumbo_rx_irq(struct
> e1000_adapter *adapter,
> prefetch(next_rxd);
>
> next_buffer = &rx_ring->buffer_info[i];
> -
nit, better to avoid random cleanups in a patch adding new (&& cool)
functionality
> cleaned = true;
> cleaned_count++;
> + length = le16_to_cpu(rx_desc->length);
> +
> + if (prog) {
> + struct page *p = buffer_info->rxbuf.page;
> + dma_addr_t dma = buffer_info->dma;
> + int act;
> +
> + if (unlikely(!(status & E1000_RXD_STAT_EOP))) {
> + /* attached bpf disallows larger than page
> + * packets, so this is hw error or corruption
> + */
> + pr_info_once("%s buggy !eop\n", netdev->name);
> + break;
> + }
> + if (unlikely(rx_ring->rx_skb_top)) {
> + pr_info_once("%s ring resizing bug\n",
> + netdev->name);
> + break;
> + }
> + dma_sync_single_for_cpu(&pdev->dev, dma,
> + length, DMA_FROM_DEVICE);
> + act = e1000_call_bpf(prog, page_address(p), length);
> + switch (act) {
> + case XDP_PASS:
> + break;
> + case XDP_TX:
> + dma_sync_single_for_device(&pdev->dev,
> + dma,
> + length,
> + DMA_TO_DEVICE);
> + e1000_xmit_raw_frame(buffer_info, length,
> + netdev, adapter);
> + /* Fallthrough to re-use mappedg page after xmit */
Did you want to say "mapped"? wasn't sure what's the role of "g" @ the end
> + case XDP_DROP:
> + default:
> + /* re-use mapped page. keep buffer_info->dma
> + * as-is, so that e1000_alloc_jumbo_rx_buffers
> + * only needs to put it back into rx ring
> + */
if we're on the XDP_TX pass, don't we need to actually see that frame
has been xmitted
before re using the page?
> + total_rx_bytes += length;
> + total_rx_packets++;
> + goto next_desc;
> + }
> + }
> +
> dma_unmap_page(&pdev->dev, buffer_info->dma,
> adapter->rx_buffer_len, DMA_FROM_DEVICE);
> buffer_info->dma = 0;
