From 56d7b53f47e7c9a0ab1c6289f2669a8d3a65cf17 Mon Sep 17 00:00:00 2001 From: stephen hemminger <stephen@networkplumber.org> Date: Fri, 27 Sep 2013 17:21:27 -0700 Subject: [PATCH] ethernet: use likely() for common Ethernet encap Mark code path's likely/unlikely based on most common usage. * Very few devices use dsa tags. * Most traffic is Ethernet (not 802.2) * No sane person uses trailer type or Novell encapsulation Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/ethernet/eth.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index f777e17d28c8..8f032bae60ad 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -179,12 +179,13 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) * variants has been configured on the receiving interface, * and if so, set skb->protocol without looking at the packet. */ - if (netdev_uses_dsa_tags(dev)) + if (unlikely(netdev_uses_dsa_tags(dev))) return htons(ETH_P_DSA); - if (netdev_uses_trailer_tags(dev)) + + if (unlikely(netdev_uses_trailer_tags(dev))) return htons(ETH_P_TRAILER); - if (ntohs(eth->h_proto) >= ETH_P_802_3_MIN) + if (likely(ntohs(eth->h_proto) >= ETH_P_802_3_MIN)) return eth->h_proto; /* @@ -193,7 +194,7 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This * won't work for fault tolerant netware but does for the rest. */ - if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF) + if (unlikely(skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF)) return htons(ETH_P_802_3); /* -- GitLab