linux-kernel - Re: [PATCH 14/23] PCI: add __pci_remove_bus

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Message-ID: <CAE9FiQVzN=JS+qNM2u9zsM05-VeghEU5hcLgy8AeDv-cMai9TQ@mail.gmail.com>
Date:	Fri, 9 Mar 2012 11:00:16 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	Jesse Barnes <jbarnes@...tuousgeek.org>, x86 <x86@...nel.org>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 14/23] PCI: add __pci_remove_bus_devices()

On Fri, Mar 9, 2012 at 9:28 AM, Bjorn Helgaas <bhelgaas@...gle.com> wrote:
> On Fri, Mar 9, 2012 at 12:17 AM, Yinghai Lu <yinghai@...nel.org> wrote:
>> On Thu, Mar 8, 2012 at 5:11 PM, Bjorn Helgaas <bhelgaas@...gle.com> wrote:
>>> On Tue, Mar 6, 2012 at 12:13 AM, Yinghai Lu <yinghai@...nel.org> wrote:
>>>> will use it with pci_stop_and_remove_bus later.
>>>>
>>>> also remove __pci_remove_behind_bridge and pci_stop_behind_bridge.
>>>>
>>>> they are same except one take bridge and one take bus.
>>>>
>>>> and we already have pci_stop_bus_devices()
>>>>
>>>> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
>>>> ---
>>>>  drivers/pci/remove.c |   28 +++++++++++-----------------
>>>>  1 files changed, 11 insertions(+), 17 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
>>>> index 243d59b..62c348c 100644
>>>> --- a/drivers/pci/remove.c
>>>> +++ b/drivers/pci/remove.c
>>>> @@ -78,7 +78,7 @@ void pci_remove_bus(struct pci_bus *pci_bus)
>>>>  }
>>>>  EXPORT_SYMBOL(pci_remove_bus);
>>>>
>>>> -static void __pci_remove_behind_bridge(struct pci_dev *dev);
>>>> +static void __pci_remove_bus_devices(struct pci_bus *bus);
>>>>  /**
>>>>  * pci_stop_and_remove_bus_device - remove a PCI device and any children
>>>>  * @dev: the device to remove
>>>> @@ -96,7 +96,7 @@ void __pci_remove_bus_device(struct pci_dev *dev)
>>>>        if (dev->subordinate) {
>>>>                struct pci_bus *b = dev->subordinate;
>>>>
>>>> -               __pci_remove_behind_bridge(dev);
>>>> +               __pci_remove_bus_devices(b);
>>>>                pci_remove_bus(b);
>>>>                dev->subordinate = NULL;
>>>>        }
>>>> @@ -111,22 +111,12 @@ void pci_stop_and_remove_bus_device(struct pci_dev *dev)
>>>>        __pci_remove_bus_device(dev);
>>>>  }
>>>>
>>>> -static void __pci_remove_behind_bridge(struct pci_dev *dev)
>>>> +static void __pci_remove_bus_devices(struct pci_bus *bus)
>>>>  {
>>>>        struct list_head *l, *n;
>>>>
>>>> -       if (dev->subordinate)
>>>> -               list_for_each_safe(l, n, &dev->subordinate->devices)
>>>> -                       __pci_remove_bus_device(pci_dev_b(l));
>>>> -}
>>>> -
>>>> -static void pci_stop_behind_bridge(struct pci_dev *dev)
>>>> -{
>>>> -       struct list_head *l, *n;
>>>> -
>>>> -       if (dev->subordinate)
>>>> -               list_for_each_safe(l, n, &dev->subordinate->devices)
>>>> -                       pci_stop_bus_device(pci_dev_b(l));
>>>> +       list_for_each_safe(l, n, &bus->devices)
>>>> +               __pci_remove_bus_device(pci_dev_b(l));
>>>
>>> Use list_for_each_entry_safe() so you don't need pci_dev_b().
>>
>> just want to keep the patch to simple, and looks like just name renaming.
>>
>> also use list_for_each_safe instead of list_for_each_entry_safe
>>
>> could have less conversion.
>
> Sorry, I didn't understand the above.
>
> It is OK to improve code as you change it :)  list_for_each_entry() is
> clearly an improvement over list_for_each() + some conversion macro.

ok, will change that.

>
>>>>  }
>>>>
>>>>  static void pci_stop_bus_devices(struct pci_bus *bus)
>>>> @@ -158,8 +148,12 @@ static void pci_stop_bus_devices(struct pci_bus *bus)
>>>>  */
>>>>  void pci_stop_and_remove_behind_bridge(struct pci_dev *dev)
>>>>  {
>>>> -       pci_stop_behind_bridge(dev);
>>>> -       __pci_remove_behind_bridge(dev);
>>>> +       struct pci_bus *bus = dev->subordinate;
>>>> +
>>>> +       if (bus) {
>>>
>>> Don't check "bus" here.  If the caller screws up and passes a
>>> non-bridge pointer, I want to learn about it rather than ignore it.
>>
>> old code have that
>>           if (dev->subordinate)
>>
>> checking.
>
> Removing a test that could silently cover a programming error is also
> an improvement.

just want to cause regression.

also it is legal that some one call it for a bridge without subordinate.

Yinghai
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