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>
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index f777e17..8f032ba 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -179,12 +179,13 @@
* 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 @@
* 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);
/*