[PATCH 3.2 049/147] ipv6: Add rt6_get_cookie() function

[Ben Hutchings]

3.2.95-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Martin KaFai Lau <kafai@xxxxxx>

commit b197df4f0f3782782e9ea8996e91b65ae33e8dd9 upstream.

Instead of doing the rt6->rt6i_node check whenever we need
to get the route's cookie.  Refactor it into rt6_get_cookie().
It is a prep work to handle FLOWI_FLAG_KNOWN_NH and also
percpu rt6_info later.

Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Cc: Julian Anastasov <ja@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2:
 - Drop changes in inet6_sk_rx_dst_set(), sctp_v6_get_dst()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -126,6 +126,11 @@ static inline struct inet6_dev *ip6_dst_
 	return ((struct rt6_info *)dst)->rt6i_idev;
 }
 
+static inline u32 rt6_get_cookie(const struct rt6_info *rt)
+{
+	return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+}
+
 struct fib6_walker_t {
 	struct list_head lh;
 	struct fib6_node *root, *node;
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -167,7 +167,7 @@ static inline void __ip6_dst_store(struc
 #ifdef CONFIG_IPV6_SUBTREES
 	np->saddr_cache = saddr;
 #endif
-	np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+	np->dst_cookie = rt6_get_cookie(rt);
 }
 
 static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -143,7 +143,7 @@ static inline void ip6_tnl_dst_reset(str
 static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
 {
 	struct rt6_info *rt = (struct rt6_info *) dst;
-	t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+	t->dst_cookie = rt6_get_cookie(rt);
 	dst_release(t->dst_cache);
 	t->dst_cache = dst;
 }
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -78,8 +78,7 @@ static int xfrm6_init_path(struct xfrm_d
 {
 	if (dst->ops->family == AF_INET6) {
 		struct rt6_info *rt = (struct rt6_info*)dst;
-		if (rt->rt6i_node)
-			path->path_cookie = rt->rt6i_node->fn_sernum;
+		path->path_cookie = rt6_get_cookie(rt);
 	}
 
 	path->u.rt6.rt6i_nfheader_len = nfheader_len;
@@ -111,8 +110,7 @@ static int xfrm6_fill_dst(struct xfrm_ds
 						   RTF_LOCAL);
 	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 	xdst->u.rt6.rt6i_node = rt->rt6i_node;
-	if (rt->rt6i_node)
-		xdst->route_cookie = rt->rt6i_node->fn_sernum;
+	xdst->route_cookie = rt6_get_cookie(rt);
 	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 	xdst->u.rt6.rt6i_src = rt->rt6i_src;
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -272,7 +272,7 @@ __ip_vs_get_out_rt_v6(struct sk_buff *sk
 				return NULL;
 			}
 			rt = (struct rt6_info *) dst;
-			cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+			cookie = rt6_get_cookie(rt);
 			__ip_vs_dst_set(dest, 0, dst_clone(&rt->dst), cookie);
 			IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
 				  &dest->addr.in6, &dest->dst_saddr.in6,