[NET] NETNS: Omit sock->sk_net without CONFIG_NET_NS.

Introduce per-sock inlines: sock_net(), sock_net_set()
and per-inet_timewait_sock inlines: twsk_net(), twsk_net_set().
Without CONFIG_NET_NS, no namespace other than &init_net exists.
Let's explicitly define them to help compiler optimizations.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 22 insertions, 2 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index b433b1ed203d..7e0d4a0c4d12 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -126,7 +126,9 @@ struct sock_common {
         atomic_t                skc_refcnt;
         unsigned int            skc_hash;
         struct proto            *skc_prot;
+#ifdef CONFIG_NET_NS
         struct net              *skc_net;
+#endif
 };
 
 /**
@@ -1345,6 +1347,24 @@ static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_e
 }
 #endif
 
+static inline
+struct net *sock_net(const struct sock *sk)
+{
+#ifdef CONFIG_NET_NS
+        return sk->sk_net;
+#else
+        return &init_net;
+#endif
+}
+
+static inline
+void sock_net_set(struct sock *sk, const struct net *net)
+{
+#ifdef CONFIG_NET_NS
+        sk->sk_net = net;
+#endif
+}
+
 /*
  * Kernel sockets, f.e. rtnl or icmp_socket, are a part of a namespace.
  * They should not hold a referrence to a namespace in order to allow
@@ -1353,8 +1373,8 @@ static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_e
  */
 static inline void sk_change_net(struct sock *sk, struct net *net)
 {
-        put_net(sk->sk_net);
-        sk->sk_net = net;
+        put_net(sock_net(sk));
+        sock_net_set(sk, net);
 }
 
 extern void sock_enable_timestamp(struct sock *sk);