[PATCH][NETNS] Move some code into __init section when CONFIG_NET_NS=n

[Pavel Emelyanov <xemul@openvz.org>]

With the net namespaces many code leaved the __init section,
thus making the kernel occupy more memory than it did before.
Since we have a config option that prohibits the namespace
creation, the functions that initialize/finalize some netns
stuff are simply not needed and can be freed after the boot.

Currently, this is almost not noticeable, since few calls
are no longer in __init, but when the namespaces will be
merged it will be possible to free more code. I propose to 
use the __net_init, __net_exit and __net_initdata "attributes"
for functions/variables that are not used if the CONFIG_NET_NS
is not set to save more space in memory.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 934c840..747170f 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -99,6 +99,15 @@ static inline void release_net(struct ne
 #define for_each_net(VAR)				\
 	list_for_each_entry(VAR, &net_namespace_list, list)
 
+#ifdef CONFIG_NET_NS
+#define __net_init
+#define __net_exit
+#define __net_initdata
+#else
+#define __net_init	__init
+#define __net_exit	__exit
+#define __net_initdata	__initdata
+#endif
 
 struct pernet_operations {
 	struct list_head list;
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index d6997ae..be25aa3 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -250,7 +250,7 @@ static void loopback_setup(struct net_de
 }
 
 /* Setup and register the loopback device. */
-static int loopback_net_init(struct net *net)
+static __net_init int loopback_net_init(struct net *net)
 {
 	struct net_device *dev;
 	int err;
@@ -278,14 +278,14 @@ out_free_netdev:
 	goto out;
 }
 
-static void loopback_net_exit(struct net *net)
+static __net_exit void loopback_net_exit(struct net *net)
 {
 	struct net_device *dev = net->loopback_dev;
 
 	unregister_netdev(dev);
 }
 
-static struct pernet_operations loopback_net_ops = {
+static struct pernet_operations __net_initdata loopback_net_ops = {
        .init = loopback_net_init,
        .exit = loopback_net_exit,
 };
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 85cc8e8..2e91fb7 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -140,7 +140,7 @@ static struct inode_operations proc_net_
 	.setattr	= proc_net_setattr,
 };
 
-static int proc_net_ns_init(struct net *net)
+static __net_init int proc_net_ns_init(struct net *net)
 {
 	struct proc_dir_entry *root, *netd, *net_statd;
 	int err;
@@ -178,19 +178,19 @@ free_root:
 	goto out;
 }
 
-static void proc_net_ns_exit(struct net *net)
+static __net_exit void proc_net_ns_exit(struct net *net)
 {
 	remove_proc_entry("stat", net->proc_net);
 	remove_proc_entry("net", net->proc_net_root);
 	kfree(net->proc_net_root);
 }
 
-struct pernet_operations proc_net_ns_ops = {
+struct pernet_operations __net_initdata proc_net_ns_ops = {
 	.init = proc_net_ns_init,
 	.exit = proc_net_ns_exit,
 };
 
-int proc_net_init(void)
+int __init proc_net_init(void)
 {
 	proc_net_shadow = proc_mkdir("net", NULL);
 	proc_net_shadow->proc_iops = &proc_net_dir_inode_operations;
diff --git a/net/core/dev.c b/net/core/dev.c
index d998646..37f8858 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2611,7 +2611,7 @@ static const struct file_operations ptyp
 };
 
 
-static int dev_proc_net_init(struct net *net)
+static int __net_init dev_proc_net_init(struct net *net)
 {
 	int rc = -ENOMEM;
 
@@ -2636,7 +2636,7 @@ out_dev:
 	goto out;
 }
 
-static void dev_proc_net_exit(struct net *net)
+static void __net_exit dev_proc_net_exit(struct net *net)
 {
 	wext_proc_exit(net);
 
@@ -2645,7 +2645,7 @@ static void dev_proc_net_exit(struct net
 	proc_net_remove(net, "dev");
 }
 
-static struct pernet_operations dev_proc_ops = {
+static struct pernet_operations __net_initdata dev_proc_ops = {
 	.init = dev_proc_net_init,
 	.exit = dev_proc_net_exit,
 };
@@ -4250,7 +4250,7 @@ static struct hlist_head *netdev_create_
 }
 
 /* Initialize per network namespace state */
-static int netdev_init(struct net *net)
+static int __net_init netdev_init(struct net *net)
 {
 	INIT_LIST_HEAD(&net->dev_base_head);
 	rwlock_init(&dev_base_lock);
@@ -4271,18 +4271,18 @@ err_name:
 	return -ENOMEM;
 }
 
-static void netdev_exit(struct net *net)
+static void __net_exit netdev_exit(struct net *net)
 {
 	kfree(net->dev_name_head);
 	kfree(net->dev_index_head);
 }
 
-static struct pernet_operations netdev_net_ops = {
+static struct pernet_operations __net_initdata netdev_net_ops = {
 	.init = netdev_init,
 	.exit = netdev_exit,
 };
 
-static void default_device_exit(struct net *net)
+static void __net_exit default_device_exit(struct net *net)
 {
 	struct net_device *dev, *next;
 	/*
@@ -4308,7 +4308,7 @@ static void default_device_exit(struct n
 	rtnl_unlock();
 }
 
-static struct pernet_operations default_device_ops = {
+static struct pernet_operations __net_initdata default_device_ops = {
 	.exit = default_device_exit,
 };
 
diff --git a/net/core/dev_mcast.c b/net/core/dev_mcast.c
index 896b0ca..15241cf 100644
--- a/net/core/dev_mcast.c
+++ b/net/core/dev_mcast.c
@@ -273,19 +273,19 @@ static const struct file_operations dev_
 
 #endif
 
-static int dev_mc_net_init(struct net *net)
+static int __net_init dev_mc_net_init(struct net *net)
 {
 	if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
 		return -ENOMEM;
 	return 0;
 }
 
-static void dev_mc_net_exit(struct net *net)
+static void __net_exit dev_mc_net_exit(struct net *net)
 {
 	proc_net_remove(net, "dev_mcast");
 }
 
-static struct pernet_operations dev_mc_net_ops = {
+static struct pernet_operations __net_initdata dev_mc_net_ops = {
 	.init = dev_mc_net_init,
 	.exit = dev_mc_net_exit,
 };
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 46eb5ea..3ef3282 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1924,7 +1924,7 @@ static struct net_proto_family netlink_f
 	.owner	= THIS_MODULE,	/* for consistency 8) */
 };
 
-static int netlink_net_init(struct net *net)
+static int __net_init netlink_net_init(struct net *net)
 {
 #ifdef CONFIG_PROC_FS
 	if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
@@ -1933,14 +1933,14 @@ static int netlink_net_init(struct net *
 	return 0;
 }
 
-static void netlink_net_exit(struct net *net)
+static void __net_exit netlink_net_exit(struct net *net)
 {
 #ifdef CONFIG_PROC_FS
 	proc_net_remove(net, "netlink");
 #endif
 }
 
-static struct pernet_operations netlink_net_ops = {
+static struct pernet_operations __net_initdata netlink_net_ops = {
 	.init = netlink_net_init,
 	.exit = netlink_net_exit,
 };