net: pass changed flags along with NETDEV_CHANGE event

Use new netdevice notifier infrastructure to pass along changed flags.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>

v2->v3: shortened notifier_info struct name
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1604,6 +1604,11 @@ struct netdev_notifier_info {
 	struct net_device *dev;
 };
 
+struct netdev_notifier_change_info {
+	struct netdev_notifier_info info; /* must be first */
+	unsigned int flags_changed;
+};
+
 static inline struct net_device *
 netdev_notifier_info_to_dev(const struct netdev_notifier_info *info)
 {

net/core/dev.c

@@ -4771,8 +4771,13 @@ void __dev_notify_flags(struct net_device *dev, unsigned int old_flags)
 	}
 
 	if (dev->flags & IFF_UP &&
-	    (changes & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI | IFF_VOLATILE)))
-		call_netdevice_notifiers(NETDEV_CHANGE, dev);
+	    (changes & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI | IFF_VOLATILE))) {
+		struct netdev_notifier_change_info change_info;
+
+		change_info.flags_changed = changes;
+		call_netdevice_notifiers_info(NETDEV_CHANGE, dev,
+					      &change_info.info);
+	}
 }
 
 /**