Re: [PATCH -v2 1/3] PCI: introduce PCIe Device Serial Number Capability support

[Yijing Wang <wangyijing@huawei.com>]

>> }
>>>
>>> +       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN);
>>> +       if (!pos)
>>> +               return 0;
>>> +
>>> +       pci_read_config_dword(dev, pos + 4,&lo);
>>> +       pci_read_config_dword(dev, pos + 8,&hi);
>>> +       sn = ((u64)hi<<  32) | lo;
>>
>> See comment below:
>>         dev->sn = ((u64)hi<<  32) | lo;
>>         return;
>>
>>> +       return sn;
>>> +}
>>> +EXPORT_SYMBOL(pci_device_serial_number);
>>> +
>>> +/**
>>>    * pci_configure_ari - enable or disable ARI forwarding
>>>    * @dev: the PCI device
>>>    *
>>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>>> index 46ada5c..c4c1a2b 100644
>>> --- a/drivers/pci/probe.c
>>> +++ b/drivers/pci/probe.c
>>> @@ -1322,6 +1322,8 @@ static void pci_init_capabilities(struct pci_dev
>>> *dev)
>>>         /* Power Management */
>>>         pci_pm_init(dev);
>>>
>>> +       dev->sn = pci_device_serial_number(dev);
>>> +
>>
>> Finally, 'the comment below':
>> I know you were following Bjorn's suggestion, which I thought
>> was an improvement, but why not do above assignment in
>> pci_device_serial_number() ?
>> See above....
> 
> pci_device_serial_number() would then have the side-effect of saving
> the result somewhere, and callers would have to know where to look.
> Personally, I think it's simpler to return the serial number directly
> and avoid the side-effect, but maybe this is just bike-shedding.
> 
> As long as we are bike-shedding, I'd just drop "sn" and do:
> 
>     return ((u64)hi << 32) | lo;
> 
> And of course, you need spaces before "&hi" and "&lo" in the
> pci_read_config_dword() calls.

OK, will drop "sn", strangely my original patch has spaces before "&hi" and "&lo",
but in reply the spaces disappeared.

Thanks!
Yijing.


> 



> .
> 


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Thanks!
Yijing