net: CONFIG_NET_SYSCTL_DEV: make per interface dev_snmp6 proc entries optional
        
Use same CONFIG_NET_SYSCTL_DEV config option (we should probably
rename it to a better name) to enable/disable per interface dev_snmp6
proc entries.

--- //packages/linux_2.6.31/rc7/src/arch/powerpc/configs/ixia_ppc750_defconfig
+++ //packages/linux_2.6.31/rc7/src/arch/powerpc/configs/ixia_ppc750_defconfig
@@ -287,6 +287,7 @@
 #
 # Networking options
 #
+# CONFIG_NET_SYSCTL_DEV is not set
 CONFIG_PACKET=y
 CONFIG_PACKET_MMAP=y
 CONFIG_UNIX=y
--- //packages/linux_2.6.31/rc7/src/net/Kconfig
+++ //packages/linux_2.6.31/rc7/src/net/Kconfig
@@ -25,6 +25,15 @@
 
 menu "Networking options"
 
+config NET_SYSCTL_DEV
+	bool "Per device sysctl entries"
+	default y
+	depends on SYSCTL
+	help
+	  Enables per device sysctl entries. You want this enabled unless
+	  your system has a large number of interfaces and you want to reduce
+	  memory usage.
+
 source "net/packet/Kconfig"
 source "net/unix/Kconfig"
 source "net/xfrm/Kconfig"
--- //packages/linux_2.6.31/rc7/src/net/ipv4/devinet.c
+++ //packages/linux_2.6.31/rc7/src/net/ipv4/devinet.c
@@ -97,7 +97,7 @@
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
 static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
 			 int destroy);
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_NET_SYSCTL_DEV
 static void devinet_sysctl_register(struct in_device *idev);
 static void devinet_sysctl_unregister(struct in_device *idev);
 #else
@@ -1397,7 +1397,6 @@
 	return ret;
 }
 
-
 #define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc, sysctl) \
 	{ \
 		.ctl_name	= NET_IPV4_CONF_ ## attr, \
@@ -1531,6 +1530,7 @@
 	kfree(t);
 }
 
+#ifdef CONFIG_NET_SYSCTL_DEV
 static void devinet_sysctl_register(struct in_device *idev)
 {
 	neigh_sysctl_register(idev->dev, idev->arp_parms, NET_IPV4,
@@ -1544,6 +1544,7 @@
 	__devinet_sysctl_unregister(&idev->cnf);
 	neigh_sysctl_unregister(idev->arp_parms);
 }
+#endif
 
 static struct ctl_table ctl_forward_entry[] = {
 	{
--- //packages/linux_2.6.31/rc7/src/net/ipv6/addrconf.c
+++ //packages/linux_2.6.31/rc7/src/net/ipv6/addrconf.c
@@ -100,7 +100,7 @@
 #define	INFINITY_LIFE_TIME	0xFFFFFFFF
 #define TIME_DELTA(a,b) ((unsigned long)((long)(a) - (long)(b)))
 
-#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_NET_SYSCTL_DEV
 static void addrconf_sysctl_register(struct inet6_dev *idev);
 static void addrconf_sysctl_unregister(struct inet6_dev *idev);
 #else
@@ -4412,6 +4412,7 @@
 	kfree(t);
 }
 
+#ifdef CONFIG_NET_SYSCTL_DEV
 static void addrconf_sysctl_register(struct inet6_dev *idev)
 {
 	neigh_sysctl_register(idev->dev, idev->nd_parms, NET_IPV6,
@@ -4427,7 +4428,7 @@
 	__addrconf_sysctl_unregister(&idev->cnf);
 	neigh_sysctl_unregister(idev->nd_parms);
 }
-
+#endif
 
 #endif