Re: 2.6.7-rc3: unregister_netdevice: waiting for tun0 to become free. Usage count = 1

[Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>]

Hello!

> It is to make sure that anyone (other cpus using the dst) who "saw"
> the old dst->dev is done doing whatever they were doing _BEFORE_
> we put the device reference.

Actually, he noticed right thing. I forgot that this function
works in context when dev, which is argument is of the function,
is held, so dev_put() here can be safely replaced with __dev_put().

So, synchonize_kernel() can be moved somewhere to unregister_netdevice(),
(maybe, it is already present there under surface)

Alexey