openvswitch: Constify various function arguments

Help produce better optimized code.

Signed-off-by: Thomas Graf <tgraf@noironetworks.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index 90a2101..25e9abc 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -66,7 +66,7 @@
 #define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))
 
 void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
-			   struct sk_buff *skb)
+			   const struct sk_buff *skb)
 {
 	struct flow_stats *stats;
 	int node = numa_node_id();
@@ -679,7 +679,7 @@
 	return key_extract(skb, key);
 }
 
-int ovs_flow_key_extract(struct ovs_tunnel_info *tun_info,
+int ovs_flow_key_extract(const struct ovs_tunnel_info *tun_info,
 			 struct sk_buff *skb, struct sw_flow_key *key)
 {
 	/* Extract metadata from packet. */