[PATCH v2 08/16] PCI: Stop and remove devices in one pass

[Bjorn Helgaas]

On Mon, Aug 20, 2012 at 10:39 PM, Yinghai Lu <yinghai at kernel.org> wrote:
> On Mon, Aug 20, 2012 at 8:27 AM, Bjorn Helgaas <bhelgaas at google.com> wrote:
>> On Fri, Aug 17, 2012 at 7:21 PM, Yinghai Lu <yinghai at kernel.org> wrote:
>>> On Fri, Aug 17, 2012 at 4:36 PM, Bjorn Helgaas <bhelgaas at google.com> wrote:
>>>> Previously, when we removed a PCI device, we made two passes over the
>>>> hierarchy rooted at the device.  In the first pass, we stopped all
>>>> the devices, and in the second, we removed them.
>>>>
>>>> This patch combines the two passes into one so that we remove a device as
>>>> soon as it and all its children have been stopped.
>>>>
>>>> Note that we previously stopped devices in reverse order and removed them
>>>> in forward order.  Now we stop and remove them in reverse order.
>>>>
>>>> Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
>>>> ---
>>>>  drivers/pci/remove.c |   42 +++++++-----------------------------------
>>>>  1 files changed, 7 insertions(+), 35 deletions(-)
>>>
>>> looks like your cleanup will have some conflict with my pci root bus
>>> hot plug branch.
>>
>> Yes, indeed, they have serious conflicts.
>>
>>> http://git.kernel.org/?p=linux/kernel/git/yinghai/linux-yinghai.git;a=blob;f=drivers/pci/remove.c;h=f672731922f8db619fb36db05dbd9c27f3253c19;hb=refs/heads/for-pci-root-bus-hotplug
>>>
>>> it add pci_stop_and_remove_bus and it depends on some functions that
>>> you kill in this patch set.
>>
>> Do you have any suggestions on how to proceed?  In my opinion,
>> remove.c is a bit of a rat's nest right now.  It took me quite a long
>> time to sort out what's going on, but when you finally get down to the
>> bottom, it's actually very simple.  So I'd really like to clean it up
>> and expose that simple structure before we throw more stuff into it.
>>
>> After my cleanup, pci_stop_and_remove_bus_device() and
>> pci_remove_bus() are the only exported interfaces left.  How hard
>> would it be to implement host bridge remove on top of that?
>>
>> I think it's OK (and even preferable) if the host bridge-related code
>> can be segregated by itself rather than being sprinkled around through
>> lots of PCI code.  So maybe the pci_is_root_bus()  and
>> pci_stop_host_bridge() stuff below could be in some sort of host
>> bridge interface that just calls the code in remove.c.
>
> Yes, your change is quite clean.
> Please go ahead to push your changes for 3.7 and my Acked-by.
>
> I would try to rebase pci-root-bus hot plug branch according to the
> output of discussion of pci mini-summit.

I fixed the pcmcia bridge check you noted, added your acks and
Yijing's tested-by, and pushed the updated branch to
http://git.kernel.org/?p=linux/kernel/git/helgaas/pci.git;a=shortlog;h=refs/heads/pci/bjorn-cleanup-remove

I plan to put it in my next branch tomorrow or Friday.

Bjorn