Commit 3797d3e8 authored Nov 07, 2013 by Eric Dumazet Committed by David S. Miller Nov 08, 2013

net: flow_dissector: small optimizations in IPv4 dissect



By moving code around, we avoid :

1) A reload of iph->ihl (bit field, so needs a mask)

2) A conditional test (replaced by a conditional mov on x86)
   Fast path loads iph->protocol anyway.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent cdc4ead0

net/core/flow_dissector.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -68,13 +68,13 @@ ip:
		iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
		if (!iph \|\| iph->ihl < 5)
		return false;
		nhoff += iph->ihl * 4;

		ip_proto = iph->protocol;
		if (ip_is_fragment(iph))
		ip_proto = 0;
		else
		ip_proto = iph->protocol;

		iph_to_flow_copy_addrs(flow, iph);
		nhoff += iph->ihl * 4;
		break;
		}
		case __constant_htons(ETH_P_IPV6): {