Re: [PATCH 6/8 v4] PCI: support the SR-IOV capability

["Zhao, Yu" <yu.zhao@intel.com>]

Matthew Wilcox wrote:
> On Tue, Oct 14, 2008 at 06:59:28PM +0800, Yu Zhao wrote:
>> +++ b/include/linux/pci.h
>> @@ -87,6 +87,12 @@ enum {
>>       /* #6: expansion ROM */
>>       PCI_ROM_RESOURCE,
>>
>> +     /* device specific resources */
>> +#ifdef CONFIG_PCI_IOV
>> +     PCI_IOV_RESOURCES,
>> +     PCI_IOV_RESOURCES_END = PCI_IOV_RESOURCES + PCI_IOV_NUM_BAR - 1,
>> +#endif
>> +
>>       /* address space assigned to buses behind the bridge */
>>  #ifndef PCI_BRIDGE_RES_NUM
>>  #define PCI_BRIDGE_RES_NUM 4
> 
> Why expand the number of resources in struct pci_dev instead of putting
> the new resources in struct pci_iov?

Yes, it's supposed to be in the 'struct pci_iov', and the resources used 
to be there in early version. But later I found all resource related 
functions such as pci_assign_resource, pdev_sort_resources, 
pbus_size_mem, etc. assume the resources are bundled with 'struct 
pci_dev' and address them using their indexes. Encapsulating resources 
into 'pci_iov' will impact all these functions. And I think we can 
postpone the change of these functions until the PCIM comes out, if the 
IOV is the only one who uses non-standard resources.

> 
> --
> Matthew Wilcox                          Intel Open Source Technology Centre
> "Bill, look, we understand that you're interested in selling us this
> operating system, but compare it to ours.  We can't possibly take such
> a retrograde step."