ipv6: move inet6_sk(sk)->rx_dst_cookie to sk->sk_rx_dst_cookie

Increase cache locality by moving rx_dst_coookie next to sk->sk_rx_dst

This removes one or two cache line misses in IPv6 early demux (TCP/UDP)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/ipv6.h

@@ -282,7 +282,6 @@ struct ipv6_pinfo {
 	__be32			rcv_flowinfo;
 
 	__u32			dst_cookie;
-	__u32			rx_dst_cookie;
 
 	struct ipv6_mc_socklist	__rcu *ipv6_mc_list;
 	struct ipv6_ac_socklist	*ipv6_ac_list;

include/net/sock.h

@@ -260,6 +260,7 @@ struct bpf_local_storage;
   *	@sk_wq: sock wait queue and async head
   *	@sk_rx_dst: receive input route used by early demux
   *	@sk_rx_dst_ifindex: ifindex for @sk_rx_dst
+  *	@sk_rx_dst_cookie: cookie for @sk_rx_dst
   *	@sk_dst_cache: destination cache
   *	@sk_dst_pending_confirm: need to confirm neighbour
   *	@sk_policy: flow policy
@@ -432,6 +433,7 @@ struct sock {
 #endif
 	struct dst_entry	*sk_rx_dst;
 	int			sk_rx_dst_ifindex;
+	u32			sk_rx_dst_cookie;
 
 	struct dst_entry __rcu	*sk_dst_cache;
 	atomic_t		sk_omem_alloc;

net/ipv6/tcp_ipv6.c

@@ -109,7 +109,7 @@ static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 
 		sk->sk_rx_dst = dst;
 		sk->sk_rx_dst_ifindex = skb->skb_iif;
-		tcp_inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
+		sk->sk_rx_dst_cookie = rt6_get_cookie(rt);
 	}
 }
 
@@ -1511,7 +1511,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 		if (dst) {
 			if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
 			    INDIRECT_CALL_1(dst->ops->check, ip6_dst_check,
-					    dst, np->rx_dst_cookie) == NULL) {
+					    dst, sk->sk_rx_dst_cookie) == NULL) {
 				dst_release(dst);
 				sk->sk_rx_dst = NULL;
 			}
@@ -1872,7 +1872,7 @@ INDIRECT_CALLABLE_SCOPE void tcp_v6_early_demux(struct sk_buff *skb)
 			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
 
 			if (dst)
-				dst = dst_check(dst, tcp_inet6_sk(sk)->rx_dst_cookie);
+				dst = dst_check(dst, sk->sk_rx_dst_cookie);
 			if (dst &&
 			    sk->sk_rx_dst_ifindex == skb->skb_iif)
 				skb_dst_set_noref(skb, dst);

net/ipv6/udp.c

@@ -884,7 +884,7 @@ static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
 	if (udp_sk_rx_dst_set(sk, dst)) {
 		const struct rt6_info *rt = (const struct rt6_info *)dst;
 
-		inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
+		sk->sk_rx_dst_cookie = rt6_get_cookie(rt);
 	}
 }
 
@@ -1073,7 +1073,7 @@ INDIRECT_CALLABLE_SCOPE void udp_v6_early_demux(struct sk_buff *skb)
 	dst = READ_ONCE(sk->sk_rx_dst);
 
 	if (dst)
-		dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
+		dst = dst_check(dst, sk->sk_rx_dst_cookie);
 	if (dst) {
 		/* set noref for now.
 		 * any place which wants to hold dst has to call