On Mon, 14 Oct 2019 12:49:55 +0200, Lorenzo Bianconi wrote:
> Implement XDP_TX verdict and ndo_xdp_xmit net_device_ops function
> pointer
>
> Signed-off-by: Lorenzo Bianconi <lore...@kernel.org>
> @@ -1972,6 +1975,109 @@ int mvneta_rx_refill_queue(struct mvneta_port *pp,
> struct mvneta_rx_queue *rxq)
> return i;
> }
>
> +static int
> +mvneta_xdp_submit_frame(struct mvneta_port *pp, struct mvneta_tx_queue *txq,
> + struct xdp_frame *xdpf, bool dma_map)
> +{
> + struct mvneta_tx_desc *tx_desc;
> + struct mvneta_tx_buf *buf;
> + dma_addr_t dma_addr;
> +
> + if (txq->count >= txq->tx_stop_threshold)
> + return MVNETA_XDP_CONSUMED;
> +
> + tx_desc = mvneta_txq_next_desc_get(txq);
> +
> + buf = &txq->buf[txq->txq_put_index];
> + if (dma_map) {
> + /* ndo_xdp_xmit */
> + dma_addr = dma_map_single(pp->dev->dev.parent, xdpf->data,
> + xdpf->len, DMA_TO_DEVICE);
> + if (dma_mapping_error(pp->dev->dev.parent, dma_addr)) {
> + mvneta_txq_desc_put(txq);
> + return MVNETA_XDP_CONSUMED;
> + }
> + buf->type = MVNETA_TYPE_XDP_NDO;
> + } else {
> + struct page *page = virt_to_page(xdpf->data);
> +
> + dma_addr = page_pool_get_dma_addr(page) +
> + pp->rx_offset_correction + MVNETA_MH_SIZE;
> + dma_sync_single_for_device(pp->dev->dev.parent, dma_addr,
> + xdpf->len, DMA_BIDIRECTIONAL);
This looks a little suspicious, XDP could have moved the start of frame
with adjust_head, right? You should also use xdpf->data to find where
the frame starts, no?
> + buf->type = MVNETA_TYPE_XDP_TX;
> + }
> + buf->xdpf = xdpf;
> +
> + tx_desc->command = MVNETA_TXD_FLZ_DESC;
> + tx_desc->buf_phys_addr = dma_addr;
> + tx_desc->data_size = xdpf->len;
> +
> + mvneta_update_stats(pp, 1, xdpf->len, true);
> + mvneta_txq_inc_put(txq);
> + txq->pending++;
> + txq->count++;
> +
> + return MVNETA_XDP_TX;
> +}
> +
> +static int
> +mvneta_xdp_xmit_back(struct mvneta_port *pp, struct xdp_buff *xdp)
> +{
> + struct xdp_frame *xdpf = convert_to_xdp_frame(xdp);
> + int cpu = smp_processor_id();
> + struct mvneta_tx_queue *txq;
> + struct netdev_queue *nq;
> + u32 ret;
> +
> + if (unlikely(!xdpf))
> + return MVNETA_XDP_CONSUMED;
Personally I'd prefer you haven't called a function which return code
has to be error checked in local variable init.
> +
> + txq = &pp->txqs[cpu % txq_number];
> + nq = netdev_get_tx_queue(pp->dev, txq->id);
> +
> + __netif_tx_lock(nq, cpu);
> + ret = mvneta_xdp_submit_frame(pp, txq, xdpf, false);
> + if (ret == MVNETA_XDP_TX)
> + mvneta_txq_pend_desc_add(pp, txq, 0);
> + __netif_tx_unlock(nq);
> +
> + return ret;
> +}
