From: Jesse Gross Date: Fri, 29 Oct 2010 12:14:53 +0000 (+0000) Subject: offloading: Make scatter/gather more tolerant of vlans. X-Git-Url: https://bbs.cooldavid.org/git/?p=net-next-2.6.git;a=commitdiff_plain;h=e1e78db628b33c657944865e3bca01ee59cc5b80 offloading: Make scatter/gather more tolerant of vlans. 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 CC: Ben Hutchings Reviewed-by: Ben Hutchings Signed-off-by: David S. Miller --- diff --git a/net/core/dev.c b/net/core/dev.c index 5968c822c99..0b403d50331 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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) { - int features = dev->features; + if (skb_is_nonlinear(skb)) { + int features = dev->features; - if (skb->protocol == htons(ETH_P_8021Q) || vlan_tx_tag_present(skb)) - features &= dev->vlan_features; + 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,