ipv6: introduce dst_rt6_info() helper

Instead of (struct rt6_info *)dst casts, we can use :

 #define dst_rt6_info(_ptr) \
         container_of_const(_ptr, struct rt6_info, dst)

Some places needed missing const qualifiers :

ip6_confirm_neigh(), ipv6_anycast_destination(),
ipv6_unicast_destination(), has_gateway()

v2: added missing parts (David Ahern)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 8 insertions, 8 deletions

diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index f253295795f0..f20dfe70fa0e 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -348,15 +348,15 @@ static int dst_fetch_ha(const struct dst_entry *dst,
 
 static bool has_gateway(const struct dst_entry *dst, sa_family_t family)
 {
-	struct rtable *rt;
-	struct rt6_info *rt6;
+	const struct rtable *rt;
+	const struct rt6_info *rt6;
 
 	if (family == AF_INET) {
 		rt = container_of(dst, struct rtable, dst);
 		return rt->rt_uses_gateway;
 	}
 
-	rt6 = container_of(dst, struct rt6_info, dst);
+	rt6 = dst_rt6_info(dst);
 	return rt6->rt6i_flags & RTF_GATEWAY;
 }
 
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
index 3de69b2eb5c4..4b5fd71c897d 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
@@ -540,7 +540,7 @@ mlxsw_sp_span_gretap6_route(const struct net_device *to_dev,
 	if (!dst || dst->error)
 		goto out;
 
-	rt6 = container_of(dst, struct rt6_info, dst);
+	rt6 = dst_rt6_info(dst);
 
 	dev = dst->dev;
 	*saddrp = fl6.saddr;
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 66f8542f3b18..784b9b2d275e 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -653,7 +653,7 @@ static int vrf_finish_output6(struct net *net, struct sock *sk,
 	skb->dev = dev;
 
 	rcu_read_lock();
-	nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
+	nexthop = rt6_nexthop(dst_rt6_info(dst), &ipv6_hdr(skb)->daddr);
 	neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
 	if (unlikely(!neigh))
 		neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 4bbfb516ac05..a9a85d0f5a5d 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2513,7 +2513,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		}
 
 		if (!info) {
-			u32 rt6i_flags = ((struct rt6_info *)ndst)->rt6i_flags;
+			u32 rt6i_flags = dst_rt6_info(ndst)->rt6i_flags;
 
 			err = encap_bypass_if_local(skb, dev, vxlan, AF_INET6,
 						    dst_port, ifindex, vni,
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 613eab729704..5f17a2a5d0e3 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -956,7 +956,7 @@ static inline struct dst_entry *qeth_dst_check_rcu(struct sk_buff *skb,
 	struct dst_entry *dst = skb_dst(skb);
 	struct rt6_info *rt;
 
-	rt = (struct rt6_info *) dst;
+	rt = dst_rt6_info(dst);
 	if (dst) {
 		if (proto == htons(ETH_P_IPV6))
 			dst = dst_check(dst, rt6_get_cookie(rt));
@@ -978,7 +978,7 @@ static inline __be32 qeth_next_hop_v4_rcu(struct sk_buff *skb,
 static inline struct in6_addr *qeth_next_hop_v6_rcu(struct sk_buff *skb,
 						    struct dst_entry *dst)
 {
-	struct rt6_info *rt = (struct rt6_info *) dst;
+	struct rt6_info *rt = dst_rt6_info(dst);
 
 	if (rt && !ipv6_addr_any(&rt->rt6i_gateway))
 		return &rt->rt6i_gateway;