ipv4: make ip_local_reserved_ports per netns

ip_local_port_range is already per netns, so should ip_local_reserved_ports
be. And since it is none by default we don't actually need it when we don't
enable CONFIG_SYSCTL.

By the way, rename inet_is_reserved_local_port() to inet_is_local_reserved_port()

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 2f0cfad..aec5e12 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -84,6 +84,10 @@
 
 	atomic_t dev_addr_genid;
 
+#ifdef CONFIG_SYSCTL
+	unsigned long *sysctl_local_reserved_ports;
+#endif
+
 #ifdef CONFIG_IP_MROUTE
 #ifndef CONFIG_IP_MROUTE_MULTIPLE_TABLES
 	struct mr_table		*mrt;