net sysctl: Initialize the network sysctls sooner to avoid problems.

If the netfilter code is modified to use register_net_sysctl_table the
kernel fails to boot because the per net sysctl infrasturce is not setup
soon enough.  So to avoid races call net_sysctl_init from sock_init().
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/net_namespace.h

@@ -283,6 +283,11 @@ struct ctl_path;
 struct ctl_table;
 struct ctl_table_header;
 
+#ifdef CONFIG_SYSCTL
+extern int net_sysctl_init(void);
+#else
+static inline int net_sysctl_init(void) { return 0; }
+#endif
 extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
 	const struct ctl_path *path, struct ctl_table *table);
 extern struct ctl_table_header *register_net_sysctl_rotable(

net/socket.c

@@ -2524,6 +2524,12 @@ EXPORT_SYMBOL(sock_unregister);
 static int __init sock_init(void)
 {
 	int err;
+	/*
+	 *      Initialize the network sysctl infrastructure.
+	 */
+	err = net_sysctl_init();
+	if (err)
+		goto out;
 
 	/*
 	 *      Initialize sock SLAB cache.

net/sysctl_net.c

@@ -89,7 +89,7 @@ static struct pernet_operations sysctl_pernet_ops = {
 };
 
 static struct ctl_table_header *net_header;
-static __init int net_sysctl_init(void)
+__init int net_sysctl_init(void)
 {
 	static struct ctl_table empty[1];
 	int ret = -ENOMEM;
@@ -109,7 +109,6 @@ static __init int net_sysctl_init(void)
 out:
 	return ret;
 }
-subsys_initcall(net_sysctl_init);
 
 struct ctl_table_header *register_net_sysctl_table(struct net *net,
 	const struct ctl_path *path, struct ctl_table *table)