ipv6: make lookups simpler and faster

TCP listener refactoring, part 4 :

To speed up inet lookups, we moved IPv4 addresses from inet to struct
sock_common

Now is time to do the same for IPv6, because it permits us to have fast
lookups for all kind of sockets, including upcoming SYN_RECV.

Getting IPv6 addresses in TCP lookups currently requires two extra cache
lines, plus a dereference (and memory stall).

inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6

This patch is way bigger than its IPv4 counter part, because for IPv4,
we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6,
it's not doable easily.

inet6_sk(sk)->daddr becomes sk->sk_v6_daddr
inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr

And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr
at the same offset.

We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic
macro.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index e7b2d4f..f6334aa 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -426,20 +426,20 @@
 {
 	addr->v6.sin6_family = AF_INET6;
 	addr->v6.sin6_port = 0;
-	addr->v6.sin6_addr = inet6_sk(sk)->rcv_saddr;
+	addr->v6.sin6_addr = sk->sk_v6_rcv_saddr;
 }
 
 /* Initialize sk->sk_rcv_saddr from sctp_addr. */
 static void sctp_v6_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
 {
 	if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
-		inet6_sk(sk)->rcv_saddr.s6_addr32[0] = 0;
-		inet6_sk(sk)->rcv_saddr.s6_addr32[1] = 0;
-		inet6_sk(sk)->rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
-		inet6_sk(sk)->rcv_saddr.s6_addr32[3] =
+		sk->sk_v6_rcv_saddr.s6_addr32[0] = 0;
+		sk->sk_v6_rcv_saddr.s6_addr32[1] = 0;
+		sk->sk_v6_rcv_saddr.s6_addr32[2] = htonl(0x0000ffff);
+		sk->sk_v6_rcv_saddr.s6_addr32[3] =
 			addr->v4.sin_addr.s_addr;
 	} else {
-		inet6_sk(sk)->rcv_saddr = addr->v6.sin6_addr;
+		sk->sk_v6_rcv_saddr = addr->v6.sin6_addr;
 	}
 }
 
@@ -447,12 +447,12 @@
 static void sctp_v6_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
 {
 	if (addr->sa.sa_family == AF_INET && sctp_sk(sk)->v4mapped) {
-		inet6_sk(sk)->daddr.s6_addr32[0] = 0;
-		inet6_sk(sk)->daddr.s6_addr32[1] = 0;
-		inet6_sk(sk)->daddr.s6_addr32[2] = htonl(0x0000ffff);
-		inet6_sk(sk)->daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
+		sk->sk_v6_daddr.s6_addr32[0] = 0;
+		sk->sk_v6_daddr.s6_addr32[1] = 0;
+		sk->sk_v6_daddr.s6_addr32[2] = htonl(0x0000ffff);
+		sk->sk_v6_daddr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
 	} else {
-		inet6_sk(sk)->daddr = addr->v6.sin6_addr;
+		sk->sk_v6_daddr = addr->v6.sin6_addr;
 	}
 }