net: split rt_genid for ipv4 and ipv6

Current net name space has only one genid for both IPv4 and IPv6, it has below
drawbacks:

- Add/delete an IPv4 address will invalidate all IPv6 routing table entries.
- Insert/remove XFRM policy will also invalidate both IPv4/IPv6 routing table
  entries even when the policy is only applied for one address family.

Thus, this patch attempt to split one genid for two to cater for IPv4 and IPv6
separately in a fine granularity.

Signed-off-by: Fan Du <fan.du@windriver.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 5 deletions

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 84e37b1ca9e1..1313456a0994 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -119,7 +119,6 @@ struct net {
         struct netns_ipvs       *ipvs;
 #endif
         struct sock             *diag_nlsk;
-        atomic_t                rt_genid;
         atomic_t                fnhe_genid;
 };
 
@@ -333,14 +332,42 @@ static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
 }
 #endif
 
-static inline int rt_genid(struct net *net)
+static inline int rt_genid_ipv4(struct net *net)
 {
-        return atomic_read(&net->rt_genid);
+        return atomic_read(&net->ipv4.rt_genid);
 }
 
-static inline void rt_genid_bump(struct net *net)
+static inline void rt_genid_bump_ipv4(struct net *net)
 {
-        atomic_inc(&net->rt_genid);
+        atomic_inc(&net->ipv4.rt_genid);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static inline int rt_genid_ipv6(struct net *net)
+{
+        return atomic_read(&net->ipv6.rt_genid);
+}
+
+static inline void rt_genid_bump_ipv6(struct net *net)
+{
+        atomic_inc(&net->ipv6.rt_genid);
+}
+#else
+static inline int rt_genid_ipv6(struct net *net)
+{
+        return 0;
+}
+
+static inline void rt_genid_bump_ipv6(struct net *net)
+{
+}
+#endif
+
+/* For callers who don't really care about whether it's IPv4 or IPv6 */
+static inline void rt_genid_bump_all(struct net *net)
+{
+        rt_genid_bump_ipv4(net);
+        rt_genid_bump_ipv6(net);
 }
 
 static inline int fnhe_genid(struct net *net)