Re: [PATCH net-next] sunvnet: call unregister_netdev() exactly once per device

[David Miller <davem@davemloft.net>]

From: sowmini.varadhan@oracle.com
Date: Tue, 8 Jul 2014 12:18:27 -0400

> unregister_netdev the parent net_device only after
> the last port in the port_list of a `struct vnet'
> is removed when the vnet is dismantled. Moreover,
> this should only be done if the net_device was
> successfully registered.
> 
> Without this fix, 'modprobe -r sunvnet' could
> trigger the following in rollback_registered_many()
> 5693   BUG_ON(dev->reg_state != NETREG_REGISTERED);
> 
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
> Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
> Acked-by: Dan Carpenter <dan.carpenter@oracle.com>

This is definitely not the right fix, you're just removing a symptom
of a much larger problem.

And that problem is that nothing cleans up the objects created by
vnet_new(), they are completely leaked.

vnet_exit(), after doing the vio_unregister_driver(), should call a
helper function that iterates over vnet_list and cleans up those
objects.

That's where the unregister_netdevice() belongs, not in vnet_port_remove().