[PATCH] ipv6: Enable RFS sk_rxhash tracking for ipv6 sockets

[Neil Horman <nhorman@tuxdriver.com>]

properly record sk_rxhash in ipv6 sockets

Noticed while working on another project that flows to sockets which I had open
on a test systems weren't getting steered properly when I had RFS enabled.
Looking more closely I found that:

1) The affected sockets were all ipv6
2) They weren't getting steered because sk->sk_rxhash was never set from the
incomming skbs on that socket.

This was occuring because there are several points in the IPv4 tcp and udp code
which save the rxhash value when a new connection is established.  Those calls
to sock_rps_save_rxhash were never added to the corresponding ipv6 code paths.
This patch adds those calls.  Tested by myself to properly enable RFS
functionalty on ipv6.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
CC: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
CC: James Morris <jmorris@namei.org>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
CC: Patrick McHardy <kaber@trash.net>
---
 net/ipv6/tcp_ipv6.c |    4 +++-
 net/ipv6/udp.c      |    2 ++
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2b0c186..97917bb 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1621,6 +1621,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 		opt_skb = skb_clone(skb, GFP_ATOMIC);
 
 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
+		sock_rps_save_rxhash(sk, skb->rxhash);
 		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
 			goto reset;
 		if (opt_skb)
@@ -1648,7 +1649,8 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 				__kfree_skb(opt_skb);
 			return 0;
 		}
-	}
+	} else
+		sock_rps_save_rxhash(sk, skb->rxhash);
 
 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
 		goto reset;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index d7037c0..aa3e327 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -505,6 +505,8 @@ int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
 	int rc;
 	int is_udplite = IS_UDPLITE(sk);
 
+	sock_rps_save_rxhash(sk, skb->rxhash);
+
 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 		goto drop;
 
-- 
1.7.4