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Commit 6ecd09dd authored Jul 12, 2012 by Eric Dumazet Committed by David S. Miller Jul 18, 2012

net: ftgmac100/ftmac100: dont pull too much data



Drivers should pull only ethernet header from page frag
to skb->head.

Pulling 64 bytes is too much for TCP (without options) on IPv4.

However, it makes sense to pull all the frame if it fits the
128 bytes bloc allocated for skb->head, to free one page per
small incoming frame.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Po-Yu Chuang <ratbert@faraday-tech.com>
Acked-by: Yan-Pai Chen <yanpai.chen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent db8dacf9

drivers/net/ethernet/faraday/ftgmac100.c

+7 −2

Original line number	Original line	Diff line number	Diff line
	@@ -479,9 +479,14 @@ static bool ftgmac100_rx_packet(struct ftgmac100 priv, int processed)
	rxdes = ftgmac100_current_rxdes(priv);		rxdes = ftgmac100_current_rxdes(priv);
	} while (!done);		} while (!done);

	if (skb->len <= 64)		/* Small frames are copied into linear part of skb to free one page */
			if (skb->len <= 128) {
	skb->truesize -= PAGE_SIZE;		skb->truesize -= PAGE_SIZE;
	__pskb_pull_tail(skb, min(skb->len, 64U));		__pskb_pull_tail(skb, skb->len);
			} else {
			/* We pull the minimum amount into linear part */
			__pskb_pull_tail(skb, ETH_HLEN);
			}
	skb->protocol = eth_type_trans(skb, netdev);		skb->protocol = eth_type_trans(skb, netdev);

	netdev->stats.rx_packets++;		netdev->stats.rx_packets++;

drivers/net/ethernet/faraday/ftmac100.c

+7 −4

Original line number	Original line	Diff line number	Diff line
	@@ -441,11 +441,14 @@ static bool ftmac100_rx_packet(struct ftmac100 priv, int processed)
	skb->len += length;		skb->len += length;
	skb->data_len += length;		skb->data_len += length;

	/* page might be freed in __pskb_pull_tail() */		if (length > 128) {
	if (length > 64)
	skb->truesize += PAGE_SIZE;		skb->truesize += PAGE_SIZE;
	__pskb_pull_tail(skb, min(length, 64));		/* We pull the minimum amount into linear part */
			__pskb_pull_tail(skb, ETH_HLEN);
			} else {
			/* Small frames are copied into linear part to free one page */
			__pskb_pull_tail(skb, length);
			}
	ftmac100_alloc_rx_page(priv, rxdes, GFP_ATOMIC);		ftmac100_alloc_rx_page(priv, rxdes, GFP_ATOMIC);

	ftmac100_rx_pointer_advance(priv);		ftmac100_rx_pointer_advance(priv);