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, 2 insertions, 2 deletions

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index edb58aff4ae7..cc34f65179e4 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -235,7 +235,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
                 if (optlen < sizeof(int) ||
                     inet_sk(sk)->inet_num)
                         goto e_inval;
-                np->ipv6only = valbool;
+                sk->sk_ipv6only = valbool;
                 retv = 0;
                 break;
 
@@ -1058,7 +1058,7 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
         }
 
         case IPV6_V6ONLY:
-                val = np->ipv6only;
+                val = sk->sk_ipv6only;
                 break;
 
         case IPV6_RECVPKTINFO: