Re: [PATCH 13/21] amd64_edac: add f10-and-later methods-p3

Ingo Molnar
2009-04-29T20:48:07Z

* Ingo Molnar <mingo@elte.hu> wrote:

>
> * Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > On Wed, 29 Apr 2009 21:23:26 +0200
> > Ingo Molnar <mingo@elte.hu> wrote:
> >
> > > > > > + if (CSFound >= 0) {
> > > > > > + *node_id = NodeID;
> > > > > > + *channel_select = ChannelSelect;
> > > > > > + }
> > > > > > + }
> > > > > > +
> > > > > > + return CSFound;
> > > > > > +}
> > > > >
> > > > > this function is probably too large, and also it uses some weird
> > > > > hungarian notation coding style. Please dont do that! It's
> > > > > completely unacceptable.
> > > >
> > > > These identifers (or at least, DctSelBaseOffsetLong, which is the
> > > > only one I googled for) come straight out of the AMD "BIOS and
> > > > Kernel Developer's Guide".
> > > >
> > > > Sucky though they are, there's value in making the kernel code
> > > > match up with the documentation.
> > >
> > > I'm generally resisting patches that hungarinize arch/x86/ (and heck
> > > there's been many attempts ...) but there's some conflicting advice
> > > here. I've Cc:-ed Linus, maybe he has an opinion about this.
> > >
> > > My gut reaction would be 'hell no'. There's other, structural
> > > problems with this code too, and doing some saner naming would
> > > mostly be a sed job and would take minimal amount of time. The
> > > naming can still be intuitive. The symbols from the documentation
> > > can perhaps be mentioned in a couple of comments to establish a
> > > mapping.
> >
> > I think I disagree. For those identifiers which map 1:1 with the
> > manufacturer's document, the ugliness involved in exactly copying
> > the manufacturer's chosen identifiers is outweighed by the benefit
> > of exactly copying the manufacturer's chosen identifiers.
> >
> > Of course, we don't have to use StinkyIdentifiers anywhere else.
> > And the nice thing about that is that when one reads the code and
> > comes across a StinkyIdentifier, one immeditely knows that it's an
> > AMD-provided thing rather than a Linux-provided thing.
> >
> > Zillions of StinkyIdentifiers get merged via this logic.
>
> Andrew, for heaven's sake, please review the patchset - as i did.

Let me apologize for this rude reply ... it appears we do agree, i
just didnt properly read your paragraphs above :-/

What i point out below is precisely what you say is ineligible
under:

> > Of course, we don't have to use StinkyIdentifiers anywhere else.

I'd extend that rule to say that StinkyIdentifiers should only be
used for hw API definitions/constants - macros, enums - not really
local variable names. The moment they are allowed into local
variables the stuff below happens.

Thanks,

Ingo

>
> The thing is, up to 12/21, the patches look like normal Linux
> patches. (there's problems with them too, but on a different level)
>
> Then do the StinkyIdentifiers show up, in full force:
>
> +static int f10_match_to_this_node(struct amd64_pvt *pvt, int DramRange,
> + u64 SystemAddr,
> + int *node_id,
> + int *channel_select)
> +{
> + int CSFound = -1;
> + int NodeID;
> + int HiRangeSelected;
> + u32 IntlvEn, IntlvSel;
> + u32 DramEn;
> + u32 Ilog;
> + u32 HoleOffset, HoleEn;
> + u32 InputAddr, Temp;
> + u32 DctSelBaseAddr, DctSelIntLvAddr;
> + u32 DctSelHi;
> + u32 ChannelSelect;
> + u64 DramBaseLong, DramLimitLong;
> + u64 DctSelBaseOffsetLong, ChannelAddrLong;
>
> Tell me, how is 'SystemAddr' or 'Temp' or 'Ilog' an AMD document
> thing?
>
> I have a much simpler explanation really: someone got really bored
> at converting some code written For Another OS, somewhere in the
> middle - and started plopping Other OS Code into a Linux driver ...
>
> I dont mind the occasional _constant_ that tells us a hw API detail
> in whatever externally dictated style - but this thing stinks
> HeadToToe ... ;-)
>
> Ingo