net: pass info struct via netdevice notifier

So far, only net_device * could be passed along with netdevice notifier
event. This patch provides a possibility to pass custom structure
able to provide info that event listener needs to know.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>

v2->v3: fix typo on simeth
	shortened dev_getter
	shortened notifier_info struct name
v1->v2: fix notifier_call parameter in call_netdevice_notifier()
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index e277e38..4b4d2b7 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -111,9 +111,9 @@
  *	Handle device status changes.
  */
 static int ax25_device_event(struct notifier_block *this, unsigned long event,
-	void *ptr)
+			     void *ptr)
 {
-	struct net_device *dev = (struct net_device *)ptr;
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
 	if (!net_eq(dev_net(dev), &init_net))
 		return NOTIFY_DONE;
@@ -1974,7 +1974,7 @@
 };
 
 static struct notifier_block ax25_dev_notifier = {
-	.notifier_call =ax25_device_event,
+	.notifier_call = ax25_device_event,
 };
 
 static int __init ax25_init(void)