Re: [PATCH 0/7][RESEND] acpi, pci: hostbridge hotplug support

[Taku Izumi <izumi.taku@jp.fujitsu.com>]

Hi Bjorn,

  Sorry for late response. 
  I've returned to Japan. It was nice to see you.

On Wed, 29 Aug 2012 23:23:49 -0700
Bjorn Helgaas <bhelgaas@google.com> wrote:

> On Thu, Aug 9, 2012 at 11:09 PM, Taku Izumi <izumi.taku@jp.fujitsu.com> wrote:
> >  Hi all,
> >
> >
> >  I'd like to merge hostbridge hotplug feature.
> >  I looked at Yinghai's branch and found that this branch contains
> >  many work and can be split into some parts.
> >  I believe it is good to merge step by step.
> >
> >  My idea is splitting into the following 4 parts:
> >    1. basic hostbirdge hotplug work
> >    2. acpiphp work
> >    3. /sysfs interface work (logical hotplug?)
> >    4. cleanup
> >
> >  This patchset is 1st step based on the following Yinghai's branch:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git
> > for-pci-root-bus-hotplug
> >
> >   * [PATCH 1/7][RESEND] x86, PCI: Fix non acpi path pci_sysdata leaking with release_fn
> >   * [PATCH 2/7][RESEND] PCI: Correctly clean up pci root buses in function pci_remove_bus()
> >   * [PATCH 3/7][RESEND] ACPI, PCI: Use normal list for struct acpi_pci_driver
> >   * [PATCH 4/7][RESEND] ACPI, PCI: Notify acpi_pci_drivers when hot-plugging PCI root bridges
> >   * [PATCH 5/7][RESEND] ACPI, PCI: Protect global lists in drivers/acpi/pci_root.c
> >   * [PATCH 6/7][RESEND] ACPI, PCI: add hostbridge removal function
> >   * [PATCH 7/7][RESEND] ACPI, PCI: add resoruce-assign code for devices under hot-added hostbridge
> 
> I looked at merging these tonight.  But I noticed there are still a
> few unanswered questions I asked earlier.
> 
> 1) For patch [1/7], I pointed out that there is currently no way to
> remove a non-ACPI host bridge, which means the fact that we don't free
> the pci_sysdata is not really a leak.  If you want to add the
> release_fn so that you can add support for removing and adding these
> non-ACPI host bridges in the future, I do not understand that.  It
> just doesn't make sense to me to try to support hotplug for those
> bridges.

  I see. I plan on ACPI-based host bridge hotplug, so I omit this patch now.

> 2) For patch [2/7], I'm still curious about the scenario where this
> patch makes a difference (see my previous response for details).

  I'll omit this patch too according to Jian's comment.

> 3) Patch [5/7], adds mutual exclusion to two different lists, using
> two different mechanisms (mutex and RCU).  It would be easier for
> people to review if this were done in two separate patches.
> 
  OK. I'll sprit into 2 patches.

  And I'll resend new version one soon.

-- 
Best regards,
Taku Izumi <izumi.taku@jp.fujitsu.com>