neigh: restore old behaviour of default parms values

Previously inet devices were only constructed when addresses are added.
Therefore the default neigh parms values they get are the ones at the
time of these operations.

Now that we're creating inet devices earlier, this changes the behaviour
of default neigh parms values in an incompatible way (see bug #8519).

This patch creates a compromise by setting the default values at the
same point as before but only for those that have not been explicitly
set by the user since the inet device's creation.

Introduced by:
commit 8030f54499925d073a88c09f30d5d844fb1b3190
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Thu Feb 22 01:53:47 2007 +0900

    [IPV4] devinet: Register inetdev earlier.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 0d678aefe69d..ae174ca565c9 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -220,6 +220,13 @@ static inline struct in_device *__in_dev_get_rtnl(const struct net_device *dev)
         return rtnl_dereference(dev->ip_ptr);
 }
 
+static inline struct neigh_parms *__in_dev_arp_parms_get_rcu(const struct net_device *dev)
+{
+        struct in_device *in_dev = __in_dev_get_rcu(dev);
+
+        return in_dev ? in_dev->arp_parms : NULL;
+}
+
 void in_dev_finish_destroy(struct in_device *idev);
 
 static inline void in_dev_put(struct in_device *idev)