Re: [PATCH] PCI: Fix device node for virtual bus

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Tue, Nov 11, 2014 at 07:55:19PM -0700, Bjorn Helgaas wrote:
>On Tue, Nov 11, 2014 at 7:42 PM, Gavin Shan <gwshan@linux.vnet.ibm.com> wrote:
>> pci_set_bus_of_node() sets virtual PCI bus's device node to PHB's
>> device node wrongly. The patch fixes the issue.
>
>This needs more detail.  How is this bug visible to users?  Is there a
>bug report?  Is this a regression?  Should it be marked for stable?
>

I don't have opened bug for it. I just found the problem (maybe not
a problem) when reading the code: The original implementation binds
PHB device-tree node with "virtual bus", which doesn't make sense.

Yes, I guess it should be marked for stable if you don't object.

>We use "virtual bus" to refer to buses created for SR-IOV VFs that are
>not on the same bus as the PF.  These virtual buses have no bridge
>device leading to them.  But I think you're talking about something
>totally different.  Or maybe that *is* what you're talking about,
>since this patch resembles 2ba29e270e97 ("PCI: Use pci_is_root_bus()
>to check for root bus").
>

"virtual bus" here is the buses created for SR-IOV VFs. Yes, the
code changes resembles commit 2ba29e270e97.

Thanks,
Gavin

>Bjorn
>
>> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>> ---
>>  drivers/pci/of.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
>> index f092993..7b2256b 100644
>> --- a/drivers/pci/of.c
>> +++ b/drivers/pci/of.c
>> @@ -31,9 +31,9 @@ void pci_release_of_node(struct pci_dev *dev)
>>
>>  void pci_set_bus_of_node(struct pci_bus *bus)
>>  {
>> -       if (bus->self == NULL)
>> +       if (pci_is_root_bus(bus))
>>                 bus->dev.of_node = pcibios_get_phb_of_node(bus);
>> -       else
>> +       else if (bus->self)
>>                 bus->dev.of_node = of_node_get(bus->self->dev.of_node);
>>  }
>>
>> --
>> 1.8.3.2
>>
>