On Fri, Sep 06, 2013 at 05:09:41PM -0600, Bjorn Helgaas wrote:
>[+cc Kenji, Alex]
>
>On Fri, Sep 06, 2013 at 09:45:56AM +0800, Wei Yang wrote:
>> In __pci_bus_size_bridges() we check whether a pci bus is a root
>> bus by testing bus->self. As indicated by commit 79af72d7
>> ("PCI: pci_is_root_bus helper"), bus->self == NULL is not a proper
>> way to check the pci root bus.
>>
>> This patch changes it to pci_is_root_bus() to check whether it is
>> a root bus.
>
>I think this is a good change, even if only on the grounds of
>consistency.
>
>Did you trip over a case where a root bus has bus->self != NULL?
>I'd like to know more details about the case where:
>
> (bus->parent == NULL) && (bus->self != NULL)
Currently no. I believe the two platforms I have met, x86 and powerpc, don't
have this status.
>
>I'm sure that situation exists, or Kenji and Alex would not have
>made the change in 79af72d7, but I don't know the details.
Agree, willing to hear about some backgroups about the original patch.
>
>I'd like to know the details so I can recognize similar problems
>elsewhere.
>
>> Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/pci/setup-bus.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>> index 520210f..989de3c 100644
>> --- a/drivers/pci/setup-bus.c
>> +++ b/drivers/pci/setup-bus.c
>> @@ -1134,7 +1134,7 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
>> }
>>
>> /* The root bus? */
>> - if (!bus->self)
>> + if (pci_is_root_bus(bus))
>> return;
>>
>> switch (bus->self->class >> 8) {
>> --
>> 1.7.1
>>
--
Richard Yang
Help you, Help me
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