Subject: Re: [PATCH 2/4] macvlan: allow in-kernel modules to create and manage macvlan devices

From: Patrick McHardy <[email-masked]>
Date: Wed, 11 Nov 2009 16:29:46 +0100

Patrick Mullaney wrote:
> The macvlan driver didn't allow for creation/deletion of devices
> by other in-kernel modules. This patch provides common routines
> for both in-kernel and netlink based management. This patch
> also enables macvlan device support for gro for lower level
> devices that support gro.

> -static void macvlan_transfer_operstate(struct net_device *dev)
> +void macvlan_transfer_operstate(struct net_device *dev)
>  {
>  	struct macvlan_dev *vlan = netdev_priv(dev);
>  	const struct net_device *lowerdev = vlan->lowerdev;
> @@ -458,6 +458,7 @@ static void macvlan_transfer_operstate(struct net_device *dev)
>  			netif_carrier_off(dev);
>  	}
>  }
> +EXPORT_SYMBOL_GPL(macvlan_transfer_operstate);

I think this function could be moved to net/core/dev.c or
net/core/link_watch.c. The VLAN code has an identical copy.

> -int macvlan_newlink(struct net_device *dev,
> -		    struct nlattr *tb[], struct nlattr *data[])
> +int macvlan_link_lowerdev(struct net_device *dev,
> +						  struct net_device *lowerdev)

Please indent this more cleanly.

>  {
>  	struct macvlan_dev *vlan = netdev_priv(dev);
>  	struct macvlan_port *port;
> +	int err = 0;
> +
> +	if (lowerdev->macvlan_port == NULL) {
> +		err = macvlan_port_create(lowerdev);
> +		if (err < 0)
> +			return err;
> +	}
> +	port = lowerdev->macvlan_port;
> +
> +	vlan->lowerdev = lowerdev;
> +	vlan->dev      = dev;
> +	vlan->port     = port;
> +	vlan->receive  = netif_rx;
> +
> +	macvlan_init(dev);
> +
> +	list_add_tail(&vlan->list, &port->vlans);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(macvlan_link_lowerdev);

> @@ -502,23 +539,14 @@ int macvlan_newlink(struct net_device *dev,
>  	if (!tb[IFLA_ADDRESS])
>  		random_ether_addr(dev->dev_addr);
>  
> -	if (lowerdev->macvlan_port == NULL) {
> -		err = macvlan_port_create(lowerdev);
> -		if (err < 0)
> -			return err;
> -	}
> -	port = lowerdev->macvlan_port;
> -
> -	vlan->lowerdev = lowerdev;
> -	vlan->dev      = dev;
> -	vlan->port     = port;
> -	vlan->receive  = netif_rx;
> +	err = macvlan_link_lowerdev(dev, lowerdev);
> +	if (err < 0)
> +		return err;
>
>  	err = register_netdevice(dev);
>  	if (err < 0)
>  		return err;

You've already added the device to the port->vlans list, so you
need to remove it again when register_netdevice() fails.

> -	list_add_tail(&vlan->list, &port->vlans);
>  	macvlan_transfer_operstate(dev);
>  	return 0;
>  }
> @@ -526,14 +554,8 @@ EXPORT_SYMBOL_GPL(macvlan_newlink);