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

From: Jiang Liu <jiang.liu@huawei.com>
To: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
	kaneshige.kenji@jp.fujitsu.com, yinghai@kernel.org
Subject: Re: [PATCH 0/7][RESEND] acpi, pci: hostbridge hotplug support
Date: Mon, 3 Sep 2012 12:04:26 +0800	[thread overview]
Message-ID: <50442C4A.9020302@huawei.com> (raw)
In-Reply-To: <20120903112845.0c583e70.izumi.taku@jp.fujitsu.com>

On 2012-9-3 10:28, Taku Izumi wrote:
> 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.
Hi Taku,
	I have already split it into two patches:)
	--Gerry

>