[NETFILTER]: Use the ctl paths instead of hand-made analogue

The conntracks subsystem has a similar infrastructure
to maintain ctl_paths, but since we already have it
on the generic level, I think it's OK to switch to
using it.

So, basically, this patch just replaces the ctl_table-s
with ctl_path-s, nf_register_sysctl_table with
register_sysctl_paths() and removes no longer needed code.

After this the net/netfilter/nf_sysctl.c file contains
the paths only.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter.h

@@ -120,12 +120,8 @@ void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
 
 #ifdef CONFIG_SYSCTL
 /* Sysctl registration */
-struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
-						  struct ctl_table *table);
-void nf_unregister_sysctl_table(struct ctl_table_header *header,
-				struct ctl_table *table);
-extern struct ctl_table nf_net_netfilter_sysctl_path[];
-extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
+extern struct ctl_path nf_net_netfilter_sysctl_path[];
+extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
 #endif /* CONFIG_SYSCTL */
 
 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];

include/net/netfilter/nf_conntrack_l3proto.h

@@ -73,7 +73,7 @@ struct nf_conntrack_l3proto
 
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header	*ctl_table_header;
-	struct ctl_table	*ctl_table_path;
+	struct ctl_path		*ctl_table_path;
 	struct ctl_table	*ctl_table;
 #endif /* CONFIG_SYSCTL */
 

net/netfilter/nf_conntrack_proto.c

@@ -36,11 +36,11 @@ static DEFINE_MUTEX(nf_ct_proto_mutex);
 
 #ifdef CONFIG_SYSCTL
 static int
-nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_table *path,
+nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path,
 		      struct ctl_table *table, unsigned int *users)
 {
 	if (*header == NULL) {
-		*header = nf_register_sysctl_table(path, table);
+		*header = register_sysctl_paths(path, table);
 		if (*header == NULL)
 			return -ENOMEM;
 	}
@@ -55,7 +55,8 @@ nf_ct_unregister_sysctl(struct ctl_table_header **header,
 {
 	if (users != NULL && --*users > 0)
 		return;
-	nf_unregister_sysctl_table(*header, table);
+
+	unregister_sysctl_table(*header);
 	*header = NULL;
 }
 #endif

net/netfilter/nf_sysctl.c

@@ -7,128 +7,19 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 
-static void
-path_free(struct ctl_table *path, struct ctl_table *table)
-{
-	struct ctl_table *t, *next;
-
-	for (t = path; t != NULL && t != table; t = next) {
-		next = t->child;
-		kfree(t);
-	}
-}
-
-static struct ctl_table *
-path_dup(struct ctl_table *path, struct ctl_table *table)
-{
-	struct ctl_table *t, *last = NULL, *tmp;
-
-	for (t = path; t != NULL; t = t->child) {
-		/* twice the size since path elements are terminated by an
-		 * empty element */
-		tmp = kmemdup(t, 2 * sizeof(*t), GFP_KERNEL);
-		if (tmp == NULL) {
-			if (last != NULL)
-				path_free(path, table);
-			return NULL;
-		}
-
-		if (last != NULL)
-			last->child = tmp;
-		else
-			path = tmp;
-		last = tmp;
-	}
-
-	if (last != NULL)
-		last->child = table;
-	else
-		path = table;
-
-	return path;
-}
-
-struct ctl_table_header *
-nf_register_sysctl_table(struct ctl_table *path, struct ctl_table *table)
-{
-	struct ctl_table_header *header;
-
-	path = path_dup(path, table);
-	if (path == NULL)
-		return NULL;
-	header = register_sysctl_table(path);
-	if (header == NULL)
-		path_free(path, table);
-	return header;
-}
-EXPORT_SYMBOL_GPL(nf_register_sysctl_table);
-
-void
-nf_unregister_sysctl_table(struct ctl_table_header *header,
-			   struct ctl_table *table)
-{
-	struct ctl_table *path = header->ctl_table;
-
-	unregister_sysctl_table(header);
-	path_free(path, table);
-}
-EXPORT_SYMBOL_GPL(nf_unregister_sysctl_table);
-
 /* net/netfilter */
-static struct ctl_table nf_net_netfilter_table[] = {
-	{
-		.ctl_name	= NET_NETFILTER,
-		.procname	= "netfilter",
-		.mode		= 0555,
-	},
-	{
-		.ctl_name	= 0
-	}
-};
-struct ctl_table nf_net_netfilter_sysctl_path[] = {
-	{
-		.ctl_name	= CTL_NET,
-		.procname	= "net",
-		.mode		= 0555,
-		.child		= nf_net_netfilter_table,
-	},
-	{
-		.ctl_name	= 0
-	}
+struct ctl_path nf_net_netfilter_sysctl_path[] = {
+	{ .procname = "net", .ctl_name = CTL_NET, },
+	{ .procname = "netfilter", .ctl_name = NET_NETFILTER, },
+	{ }
 };
 EXPORT_SYMBOL_GPL(nf_net_netfilter_sysctl_path);
 
 /* net/ipv4/netfilter */
-static struct ctl_table nf_net_ipv4_netfilter_table[] = {
-	{
-		.ctl_name	= NET_IPV4_NETFILTER,
-		.procname	= "netfilter",
-		.mode		= 0555,
-	},
-	{
-		.ctl_name	= 0
-	}
-};
-static struct ctl_table nf_net_ipv4_table[] = {
-	{
-		.ctl_name	= NET_IPV4,
-		.procname	= "ipv4",
-		.mode		= 0555,
-		.child		= nf_net_ipv4_netfilter_table,
-	},
-	{
-		.ctl_name	= 0
-	}
-};
-struct ctl_table nf_net_ipv4_netfilter_sysctl_path[] = {
-	{
-		.ctl_name	= CTL_NET,
-		.procname	= "net",
-		.mode		= 0555,
-		.child		= nf_net_ipv4_table,
-	},
-	{
-		.ctl_name	= 0
-	}
+struct ctl_path nf_net_ipv4_netfilter_sysctl_path[] = {
+	{ .procname = "net", .ctl_name = CTL_NET, },
+	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
+	{ .procname = "netfilter", .ctl_name = NET_IPV4_NETFILTER, },
+	{ }
 };
 EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);