hv_netvsc: Fix race of register_netdevice_notifier and VF register

If VF NIC is registered earlier, NETDEV_REGISTER event is replayed,
but NETDEV_POST_INIT is not.

Move register_netdevice_notifier() earlier, so the call back
function is set before probing.

Cc: [email protected]
Fixes: e04e7a7bbd ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
Reported-by: Dexuan Cui <[email protected]>
Signed-off-by: Haiyang Zhang <[email protected]>
Reviewed-by: Wojciech Drewek <[email protected]>
Reviewed-by: Dexuan Cui <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>

drivers/net/hyperv/netvsc_drv.c

@@ -2793,12 +2793,17 @@ static int __init netvsc_drv_init(void)
 	}
 	netvsc_ring_bytes = ring_size * PAGE_SIZE;
 
+	register_netdevice_notifier(&netvsc_netdev_notifier);
+
 	ret = vmbus_driver_register(&netvsc_drv);
 	if (ret)
-		return ret;
+		goto err_vmbus_reg;
 
-	register_netdevice_notifier(&netvsc_netdev_notifier);
 	return 0;
+
+err_vmbus_reg:
+	unregister_netdevice_notifier(&netvsc_netdev_notifier);
+	return ret;
 }
 
 MODULE_LICENSE("GPL");