inet: move ipv6only in sock_common

When an UDP application switches from AF_INET to AF_INET6 sockets, we
have a small performance degradation for IPv4 communications because of
extra cache line misses to access ipv6only information.

This can also be noticed for TCP listeners, as ipv6_only_sock() is also
used from __inet_lookup_listener()->compute_score()

This is magnified when SO_REUSEPORT is used.

Move ipv6only into struct sock_common so that it is available at
no extra cost in lookups.

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

1 files changed, 1 insertions, 2 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 95c834799288..c2bd28fd43e4 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -79,7 +79,6 @@ static unsigned int udp6_ehashfn(struct net *net,
 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
 {
         const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
-        int sk_ipv6only = ipv6_only_sock(sk);
         int sk2_ipv6only = inet_v6_ipv6only(sk2);
         int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
         int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
@@ -95,7 +94,7 @@ int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
                 return 1;
 
         if (addr_type == IPV6_ADDR_ANY &&
-            !(sk_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
+            !(ipv6_only_sock(sk) && addr_type2 == IPV6_ADDR_MAPPED))
                 return 1;
 
         if (sk2_rcv_saddr6 &&