OK, here is an implementation with threaded irqs. Still not sure about 
the locking stuff. Maybe someone experienced with uart drivers can help?

Am 14.09.2010 15:27, schrieb Jonathan Corbet:
> On Tue, 14 Sep 2010 15:07:13 +0200
> Manuel Stahl<manuel.stahl@iis.fraunhofer.de>  wrote:
>
>> Where can I find some example how to use the new threaded irqs?
>
> Basic description here: http://lwn.net/Articles/302043/
>
> If you grep request_threaded_irq() in drivers/, you'll certainly find
> some real-world examples.
>
> jon