Re: User mode drivers: part 2: PCI device handling (patch 1/2 for 2.6.11)

[Albert Cahalan <albert@users.sf.net>]

On Fri, 2005-03-11 at 19:15 +0000, Alan Cox wrote:
> > You forgot the PCI domain (a.k.a. hose, phb...) number.
> > Also, you might encode bus,slot,function according to
> > the PCI spec. So that gives:
> > 
> > long usr_pci_open(unsigned pcidomain, unsigned devspec, __u64 dmamask);
> 
> Still insufficient because the device might be hotplugged on you. You
> need a file handle that has the expected revocation effects on unplug
> and refcounts

I was under the impression that a file handle would be returned.

I'm not so sure that is a sane way to handle hot-plug though.
First of all, in general, it's going to be like this:

Fan, meet shit.
Shit, meet fan.

Those who care might best be served by SIGBUS with si_code
and si_info set appropriately. Perhaps a revoke() syscall
that handled mmap() would work the same way.