Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus domain number.

Arnd Bergmann
2016-04-29T22:50:11Z

On Thursday 28 April 2016 17:34:10 Arnd Bergmann wrote:
> On Thursday 28 April 2016 10:12:12 Bjorn Helgaas wrote:
> > Right, we don't have a good mechanism for passing more info into
> > pci_create_root_bus(). Maybe the caller could fill in a struct so we
> > have a chance to extend it without having to change all the existing
> > callers.
> >
> > I wonder if there's a design pattern we can copy, e.g., would
> > something like the scsi_host_alloc(), scsi_add_host(),
> > scsi_scan_host() model work here?
>
> Yes, I think that is a good idea in general. Especially
> now that we have separate the ARM code from pci_common_init_dev
> and pci_sys_data, that can help with cleanups in the other drivers
> as well.
>
> I see two common variations in other subsystems: some use a
> special alloc() function that you pass the size of the private
> data into, while others just expect you to embed a structure
> inside of the driver specific one allocate that separately to
> have the generic registration function fill out the common fields.
>
> I have a slight preference for the second, but they are really
> the same thing basically.

I've tried this out now, and will follow up with a separate patch
series. Overall, I think it works out well, though I haven't gotten
to the point of actually saving code yet. I've converted two
drivers for demonstration.

Arnd