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/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 71c2c711..34fbc2f 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -3269,9 +3269,9 @@
 }
 
 static int cma_netdev_callback(struct notifier_block *self, unsigned long event,
-			       void *ctx)
+			       void *ptr)
 {
-	struct net_device *ndev = (struct net_device *)ctx;
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
 	struct cma_device *cma_dev;
 	struct rdma_id_private *id_priv;
 	int ret = NOTIFY_DONE;