linux-kernel - Re: [PATCH v25 01/10] drivers/base: refactor cpu.c to use .is

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Message-ID: <a6dd6e27-e8a7-09ac-f33d-03318dd5695c@oracle.com>
Date:   Thu, 3 Aug 2023 13:20:28 -0500
From:   Eric DeVolder <eric.devolder@...cle.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, david@...hat.com, osalvador@...e.de,
        corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
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        sourabhjain@...ux.ibm.com, konrad.wilk@...cle.com,
        boris.ostrovsky@...cle.com
Subject: Re: [PATCH v25 01/10] drivers/base: refactor cpu.c to use
 .is_visible()



On 7/21/23 11:32, Eric DeVolder wrote:
> 
> 
> On 7/3/23 11:53, Eric DeVolder wrote:
>>
>>
>> On 7/3/23 08:05, Greg KH wrote:
>>> On Thu, Jun 29, 2023 at 03:21:10PM -0400, Eric DeVolder wrote:
>>>>   - the function body of the callback functions are now wrapped with
>>>>     IS_ENABLED(); as the callback function must exist now that the
>>>>     attribute is always compiled-in (though not necessarily visible).
>>>
>>> Why do you need to do this last thing?  Is it a code savings goal?  Or
>>> something else?  The file will not be present in the system if the
>>> option is not enabled, so it should be safe to not do this unless you
>>> feel it's necessary for some reason?
>>
>> To accommodate the request, all DEVICE_ATTR() must be unconditionally present in this file. The 
>> DEVICE_ATTR() requires the .show() callback. As the callback is referenced from a data structure, 
>> the callback has to be present for link. All the callbacks for these attributes are in this file.
>>
>> I have two basic choices for gutting the function body if the config feature is not enabled. I can 
>> either use #ifdef or IS_ENABLED(). Thomas has made it clear I need to use IS_ENABLED(). I can 
>> certainly use #ifdef (which is what I did in v24).
>>
>>>
>>> Not doing this would make the diff easier to read :)
>>
>> I agree this is messy. I'm not really sure what this request/effort achieves as these attributes 
>> are not strongly related (unlike cacheinfo) and the way the file was before results in less code.
>>
>> At any rate, please indicate if you'd rather I use #ifdef.
>> Thanks for your time!
>> eric
>>
>>>
>>> thanks,
>>>
>>> greg k-h
> 
> Hi Greg,
> I was wondering if you might weigh-in so that I can proceed.
> 
> I think there are three options on the table:
> - use #ifdef to comment out these function bodies, which keeps the diff much more readable
> - use IS_ENABLED() as Thomas has requested I do, but makes the diff more difficult to read
> - remove this refactor altogether, perhaps post-poning until after this crash hotplug series merges, 
> as this refactor is largely unrelated to crash hotplug.
> 
> Thank you for your time on this topic!
> eric

Hi Greg,
If you have an opinion on how to proceed, please provide.
Thanks,
eric