[IPV4]: Add default config support after inetdev_init

Previously once inetdev_init has been called on a device any changes
made to ipv4_devconf_dflt would have no effect on that device's
configuration.

This creates a problem since we have moved the point where
inetdev_init is called from when an address is added to where the
device is registered.

This patch is the first half of a set that tries to mimic the old
behaviour while still calling inetdev_init.

It propagates any changes to ipv4_devconf_dflt to those devices that
have not had the corresponding attribute set.

The next patch will forcibly set all values at the point where
inetdev_init was previously called.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 1ef174d83e09..40adefdfe5d1 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -3,6 +3,7 @@
 
 #ifdef __KERNEL__
 
+#include <linux/bitmap.h>
 #include <linux/if.h>
 #include <linux/netdevice.h>
 #include <linux/rcupdate.h>
@@ -12,6 +13,7 @@ struct ipv4_devconf
 {
 	void	*sysctl;
 	int	data[__NET_IPV4_CONF_MAX - 1];
+	DECLARE_BITMAP(state, __NET_IPV4_CONF_MAX - 1);
 };
 
 extern struct ipv4_devconf ipv4_devconf;
@@ -53,6 +55,7 @@ static inline void ipv4_devconf_set(struct in_device *in_dev, int index,
 				    int val)
 {
 	index--;
+	set_bit(index, in_dev->cnf.state);
 	in_dev->cnf.data[index] = val;
 }