netns: constify net_hash_mix() and various callers

const qualifiers ease code review by making clear
which objects are not written in a function.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index f27556e..294af16 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -318,8 +318,8 @@
 		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 }
 
-static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
-				       unsigned int port)
+static u32 udp4_portaddr_hash(const struct net *net, __be32 saddr,
+			      unsigned int port)
 {
 	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 }
@@ -421,9 +421,9 @@
 	return score;
 }
 
-static unsigned int udp_ehashfn(struct net *net, const __be32 laddr,
-				 const __u16 lport, const __be32 faddr,
-				 const __be16 fport)
+static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
+		       const __u16 lport, const __be32 faddr,
+		       const __be16 fport)
 {
 	static u32 udp_ehash_secret __read_mostly;