ohci1394 and pcilynx can be unloaded while an application is using a host
adapter through raw1394. This especially happens if dv1394 or video1394 are
unloaded because this decrements ohci1394's use count. The result is inadvertent
loss of functionality or even system-wide lock-up, if ohci1394 is reloaded after
this. http://lkml.org/lkml/2006/12/17/91

I think we should add try_module_get(host->driver->owner) and
module_put(host->driver->owner)
 - either to initiation and release of requests,
 - or to the raw1394_open() and raw1394_release() hooks for all hosts which are
present when the file is opened,
 - or simply to raw1394's add_host() and remove_host() hooks.