Re: [PATCH] Gigabit Ethernet driver of Topcliff PCH

Eric Dumazet
2010-08-31T15:13:11Z

Le mardi 31 août 2010 à 23:15 +0900, Masayuki Ohtake a écrit :
> Hi Sam, Joe and Stephen
>
> Thank you for your comments.
> We have modified this driver for your comment.
>
> ---
> Gigabit Ethernet driver of Topcliff PCH

> + skb->protocol = eth_type_trans(skb, netdev);
> + if ((tcp_ip_status & PCH_GBE_RXD_ACC_STAT_TCPIPOK) ==
> + PCH_GBE_RXD_ACC_STAT_TCPIPOK) {
> + skb->ip_summed = CHECKSUM_UNNECESSARY;
> + } else {
> + skb->ip_summed = CHECKSUM_NONE;
> + }
> +
> + if (netif_receive_skb(skb) == NET_RX_DROP) {
> + adapter->stats.rx_dropped++;

dont use pr_err() here, dropping a frame is a normal condition.

> + pr_err("Receive Netif Receive Dropped Error\n");
> + }
> + (*work_done)++;
> + netdev->last_rx = jiffies;

really ? last_rx is a thing of the past.

> + pr_debug
> + ("Receive skb->ip_summed: %d length: %d\n",
> + skb->ip_summed, length);
> + }
> +dorrop:
> + /* return some buffers to hardware, one at a time is too slow */
> + if (unlikely(cleaned_count >= PCH_GBE_RX_BUFFER_WRITE)) {
> + pch_gbe_alloc_rx_buffers(adapter, rx_ring,
> + cleaned_count);
> + cleaned_count = 0;
> + }
> + if (++i == rx_ring->count)
> + i = 0;
> + }
> + rx_ring->next_to_clean = i;
> + if (cleaned_count)
> + pch_gbe_alloc_rx_buffers(adapter, rx_ring, cleaned_count);
> + return cleaned;
> +}
> +

I find hard to believe this driver needs to copy all outgoing frames on
pre-allocated skbs.

+ /* [Header:14][payload] ---> [Header:14][paddong:2][payload] */
+ memcpy(tmp_skb->data, skb->data, ETH_HLEN);
+ tmp_skb->data[ETH_HLEN] = 0x00;
+ tmp_skb->data[ETH_HLEN + 1] = 0x00;
+ tmp_skb->len = skb->len;
+ memcpy(&tmp_skb->data[ETH_HLEN + 2], &skb->data[ETH_HLEN],
+ (skb->len - ETH_HLEN));
+ buffer_info->kernel_skb = skb;
+ skb = tmp_skb;

Whats the deal here please ?