Re: [PATCH 0/3] ACPI/PCI Hotplug: acpiphp cleanup

[Jesse Barnes]

On Tue, 14 Jul 2009 14:04:31 -0600
Alex Chiang <achiang@xxxxxx> wrote:

> * Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>:
> > Haven't heard from Len yet, but I'm a bit nervous about adding this
> > to for-linus.  We already have a fix upstream for the
> > acpi_get_pci_dev issue right?  So there's no hurry on this set of
> > (nice) cleanups is there?
> 
> The problem is that I introduced an assumption in
> acpiphp_configure_bridge, which calls acpi_get_pci_dev. That call may
> fail on systems with non-materialized PCI root bridges.
> 
> Fixing that assumption was addressed by this hunk in patch 2/3:
> 
> @@ -1387,16 +1363,7 @@ static void acpiphp_sanitize_bus(struct
> pci_bus *bus) /* Program resources in newly inserted bridge */
>  static int acpiphp_configure_bridge (acpi_handle handle)
>  {
> -       struct pci_dev *dev;
> -       struct pci_bus *bus;
> -
> -       dev = acpi_get_pci_dev(handle);
> -       if (!dev) {
> -               err("cannot get PCI domain and bus number for
> bridge\n");
> -               return -EINVAL;
> -       }
> -
> -       bus = dev->bus;
> +       struct pci_bus *bus = pci_bus_from_handle(handle);
> 
>         pci_bus_size_bridges(bus);
>         pci_bus_assign_resources(bus);
> 
> Now, my systems cannot do PCI root bridge hotplug, so that line
> where we call acpi_get_pci_dev() won't cause us to fail, but I'm
> concerned about machines in the wild that:
> 
> 	a) can do PCI root bridge hotplug
> 	b) have non-materialized PCI root bridges
> 
> Maybe that is a small set of machines...
> 
> I agree that this series is on the large side for -rc4 and
> beyond, but I'd prefer to fix it now.
> 
> The thing is, a "minimal" fix wouldn't save us that much, since
> we'd still have to export acpi_pci_root stuff. We could maybe
> drop patch 3/3 which makes the final diffstat look like this:
> 
>  drivers/acpi/pci_root.c            |   17 +-----
>  include/acpi/acpi_bus.h            |   14 +++++
>  drivers/pci/hotplug/acpiphp_glue.c |  108
> ++++++++++++------------------------ 3 files changed, 53
> insertions(+), 86 deletions(-)
> 
> Hm, actually, I can actually make that even smaller by separating
> out the interface change.
> 
> Would you like me to do that and resubmit? I'd still need an ACK
> from Len re: acpi_pci_root...

How about I actually send a reply this time...

No you don't need to re-submit; assuming Len comes back quickly we can
put this into my for-linus branch. Len, we just need your ack to apply
this series.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center
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