offloading: Make scatter/gather more tolerant of vlans. (e1e78db6) · Commits · 戴 / test

When checking if it is necessary to linearize a packet, we currently use vlan_features if the packet contains either an in-band or out- of-band vlan tag. However, in-band tags aren't special in any way for scatter/gather since they are part of the packet buffer and are simply more data to DMA. Therefore, only use vlan_features for out- of-band tags, which could potentially have some interaction with scatter/gather. Signed-off-by:

Jesse Gross <jesse@nicira.com> CC: Ben Hutchings <bhutchings@solarflare.com> Reviewed-by:

Ben Hutchings <bhutchings@solarflare.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/dev.c

+12 −7

Original line number	Diff line number	Diff line
		@@ -1976,15 +1976,20 @@ static inline void skb_orphan_try(struct sk_buff *skb)
		static inline int skb_needs_linearize(struct sk_buff *skb,
		struct net_device *dev)
		{
		if (skb_is_nonlinear(skb)) {
		int features = dev->features;

		if (skb->protocol == htons(ETH_P_8021Q) \|\| vlan_tx_tag_present(skb))
		if (vlan_tx_tag_present(skb))
		features &= dev->vlan_features;

		return skb_is_nonlinear(skb) &&
		((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) \|\|
		(skb_shinfo(skb)->nr_frags && (!(features & NETIF_F_SG) \|\|
		illegal_highdma(dev, skb))));
		return (skb_has_frag_list(skb) &&
		!(features & NETIF_F_FRAGLIST)) \|\|
		(skb_shinfo(skb)->nr_frags &&
		(!(features & NETIF_F_SG) \|\|
		illegal_highdma(dev, skb)));
		}

		return 0;
		}

		int dev_hard_start_xmit(struct sk_buff skb, struct net_device dev,

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