Thread (34 messages) 34 messages, 7 authors, 2010-09-07

Re: [PATCH] Gigabit Ethernet driver of Topcliff PCH

From: Eric Dumazet <hidden>
Date: 2010-08-31 15:13:11
Also in: lkml

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 ?
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