[PATCH v2] net: inline function get_net_ns_by_fd if NET_NS is disabled

[Changbin Du <changbin.du@xxxxxxxxx>]

The function get_net_ns_by_fd() could be inlined when NET_NS is not
enabled.

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>

---
v2: rebase to net-tree.
---
 include/net/net_namespace.h | 7 ++++++-
 net/core/net_namespace.c    | 8 +-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 6412d7833d97..bdc0459a595e 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -186,6 +186,7 @@ void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);
 void net_ns_barrier(void);
 
 struct ns_common *get_net_ns(struct ns_common *ns);
+struct net *get_net_ns_by_fd(int fd);
 #else /* CONFIG_NET_NS */
 #include <linux/sched.h>
 #include <linux/nsproxy.h>
@@ -210,13 +211,17 @@ static inline struct ns_common *get_net_ns(struct ns_common *ns)
 {
 	return ERR_PTR(-EINVAL);
 }
+
+static inline struct net *get_net_ns_by_fd(int fd)
+{
+	return ERR_PTR(-EINVAL);
+}
 #endif /* CONFIG_NET_NS */
 
 
 extern struct list_head net_namespace_list;
 
 struct net *get_net_ns_by_pid(pid_t pid);
-struct net *get_net_ns_by_fd(int fd);
 
 #ifdef CONFIG_SYSCTL
 void ipx_register_sysctl(void);
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index cc8dafb25d61..9b5a767eddd5 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -672,14 +672,8 @@ struct net *get_net_ns_by_fd(int fd)
 	fput(file);
 	return net;
 }
-
-#else
-struct net *get_net_ns_by_fd(int fd)
-{
-	return ERR_PTR(-EINVAL);
-}
-#endif
 EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
+#endif
 
 struct net *get_net_ns_by_pid(pid_t pid)
 {
-- 
2.30.2