[NETNS]: Introduce a netns_core structure.

There's already some stuff on the struct net, that should better
be folded into netns_core structure. I'm making the per-proto inuse 
counter be per-net also, which is also a candidate for this, so 
introduce this structure and populate it a bit.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/net_namespace.h

@@ -8,6 +8,7 @@
 #include <linux/workqueue.h>
 #include <linux/list.h>
 
+#include <net/netns/core.h>
 #include <net/netns/unix.h>
 #include <net/netns/packet.h>
 #include <net/netns/ipv4.h>
@@ -46,10 +47,7 @@ struct net {
 
 	struct sock 		*rtnl;			/* rtnetlink socket */
 
-	/* core sysctls */
-	struct ctl_table_header	*sysctl_core_hdr;
-	int			sysctl_somaxconn;
-
+	struct netns_core	core;
 	struct netns_packet	packet;
 	struct netns_unix	unx;
 	struct netns_ipv4	ipv4;

include/net/netns/core.h

+#ifndef __NETNS_CORE_H__
+#define __NETNS_CORE_H__
+
+struct ctl_table_header;
+
+struct netns_core {
+	/* core sysctls */
+	struct ctl_table_header	*sysctl_hdr;
+
+	int	sysctl_somaxconn;
+};
+
+#endif

net/core/sysctl_net_core.c

@@ -127,7 +127,7 @@ static struct ctl_table net_core_table[] = {
 	{
 		.ctl_name	= NET_CORE_SOMAXCONN,
 		.procname	= "somaxconn",
-		.data		= &init_net.sysctl_somaxconn,
+		.data		= &init_net.core.sysctl_somaxconn,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec
@@ -161,7 +161,7 @@ static __net_init int sysctl_core_net_init(struct net *net)
 {
 	struct ctl_table *tbl, *tmp;
 
-	net->sysctl_somaxconn = SOMAXCONN;
+	net->core.sysctl_somaxconn = SOMAXCONN;
 
 	tbl = net_core_table;
 	if (net != &init_net) {
@@ -178,9 +178,9 @@ static __net_init int sysctl_core_net_init(struct net *net)
 		}
 	}
 
-	net->sysctl_core_hdr = register_net_sysctl_table(net,
+	net->core.sysctl_hdr = register_net_sysctl_table(net,
 			net_core_path, tbl);
-	if (net->sysctl_core_hdr == NULL)
+	if (net->core.sysctl_hdr == NULL)
 		goto err_reg;
 
 	return 0;
@@ -196,8 +196,8 @@ static __net_exit void sysctl_core_net_exit(struct net *net)
 {
 	struct ctl_table *tbl;
 
-	tbl = net->sysctl_core_hdr->ctl_table_arg;
-	unregister_net_sysctl_table(net->sysctl_core_hdr);
+	tbl = net->core.sysctl_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->core.sysctl_hdr);
 	BUG_ON(tbl == net_core_table);
 	kfree(tbl);
 }

net/socket.c

@@ -1375,7 +1375,7 @@ asmlinkage long sys_listen(int fd, int backlog)
 
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (sock) {
-		somaxconn = sock_net(sock->sk)->sysctl_somaxconn;
+		somaxconn = sock_net(sock->sk)->core.sysctl_somaxconn;
 		if ((unsigned)backlog > somaxconn)
 			backlog = somaxconn;