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SubjectRe: [PATCH ref0] net: add Faraday FTMAC100 10/100 Ethernet driver
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Le jeudi 24 février 2011 à 17:29 +0800, Po-Yu Chuang a écrit :
> From: Po-Yu Chuang <ratbert@faraday-tech.com>
>


> +
> +static bool ftmac100_rx_packet(struct ftmac100 *priv, int *processed)
> +{
> + struct net_device *netdev = priv->netdev;
> + struct ftmac100_rxdes *rxdes;
> + struct sk_buff *skb;
> + struct page *page;
> + dma_addr_t map;
> + int length;
> +
> + rxdes = ftmac100_rx_locate_first_segment(priv);
> + if (!rxdes)
> + return false;
> +
> + if (unlikely(ftmac100_rx_packet_error(priv, rxdes))) {
> + ftmac100_rx_drop_packet(priv);
> + return true;
> + }
> +
> + /*
> + * It is impossible to get multi-segment packets
> + * because we always provide big enough receive buffers.
> + */
> + if (unlikely(!ftmac100_rxdes_last_segment(rxdes)))
> + BUG();
> +
> + /* start processing */
> + skb = netdev_alloc_skb_ip_align(netdev, ETH_HLEN);

Oh I see... You should allocate a bigger head (say... 128 bytes)

And copy in it up to 128 bytes of first part... this to avoid upper
stack to reallocate skb head (because IP/TCP processing need to get
their headers in skb head)

> + if (unlikely(!skb)) {
> + if (net_ratelimit())
> + netdev_err(netdev, "rx skb alloc failed\n");
> +
> + ftmac100_rx_drop_packet(priv);
> + return true;
> + }
> +
> + if (unlikely(ftmac100_rxdes_multicast(rxdes)))
> + netdev->stats.multicast++;
> +
> + map = ftmac100_rxdes_get_dma_addr(rxdes);
> + dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);
> +
> + length = ftmac100_rxdes_frame_length(rxdes);
> + page = ftmac100_rxdes_get_page(rxdes);
> + skb_fill_page_desc(skb, 0, page, 0, length);
> + skb->len += length;
> + skb->data_len += length;
> + skb->truesize += length;
> + __pskb_pull_tail(skb, ETH_HLEN);
> +
> + ftmac100_alloc_rx_page(priv, rxdes);
> +
> + ftmac100_rx_pointer_advance(priv);
> +
> + skb->protocol = eth_type_trans(skb, netdev);
> +
> + netdev->stats.rx_packets++;
> + netdev->stats.rx_bytes += skb->len;
> +
> + /* push packet to protocol stack */
> + netif_receive_skb(skb);
> +
> + (*processed)++;
> + return true;
> +}
> +

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