Date: Sat, 31 Dec 2005 00:46:28 +0100
From: Adrian Bunk <bunk@stusta.de>
To: Matt Mackall <mpm@selenic.com>
Cc: "Bryan O'Sullivan" <bos@pathscale.com>, Roland Dreier <rdreier@cisco.com>,
       linux-kernel@vger.kernel.org, akpm@osdl.org, hch@infradead.org,
       Linus Torvalds <torvalds@osdl.org>
Subject: Re: [PATCH 1 of 3] Introduce __memcpy_toio32
Message-ID: <20051230234628.GB3811@stusta.de>
References: <7b7b442a4d6338ae8ca7.1135726915@eng-12.pathscale.com> <adazmmmc9hl.fsf@cisco.com> <1135780804.1527.82.camel@serpentine.pathscale.com> <20051228145114.GL3356@waste.org>
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On Wed, Dec 28, 2005 at 08:51:14AM -0600, Matt Mackall wrote:
> On Wed, Dec 28, 2005 at 06:40:03AM -0800, Bryan O'Sullivan wrote:
> > On Tue, 2005-12-27 at 17:10 -0800, Roland Dreier wrote:
> > 
> > > I think the principle of least surprise calls for memcpy_toio32 to be
> > > ordered the same way memcpy_toio is.  In other words there should be a
> > > wmb() after the loop.
> > 
> > Will do.
> > 
> > > Also, no need for the { } for the while loop.
> > 
> > Fine.  There doesn't seem to be much consistency in whether to use
> > curlies for single-line blocks.
> 
> We've been very consistent in discouraging it in new code. Enforcement
> of fine points of coding style is a post-2.5 phenomenon, so it hasn't
> hit all the tree yet.
> 
> > > You're adding this symbol and exporting it even if the arch will
> > > supply its own version.  So this is pure kernel .text bloat...
> > 
> > I don't know what you'd prefer, so let me enumerate a few alternatives,
> > and you can either tell me which you'd prefer, or point out something
> > I've missed that would be even better.  I'm entirely flexible on this.
> > 
> >       * Use the __HAVE_ARCH_* mechanism that include/asm-*/string.h
> >         uses.  Caveat: Linus has lately come out as hating this style.
> >         It makes for the smallest patch, though.
> >       * Define the generic code in lib/, and have each arch that really
> >         uses it export it.
> 
> I'd favor this, at least for this case. If it becomes more widely
> used, we'll relocate the export.
>...

I don't like this for two reasons:
- we are moving exports to the actual functions and steadily killing all
  *syms* files
- the lib-y approach has the disadvantage of completely omitting the
  function if it's used only in modules resulting in non-working
  modules

Where's the problem with the __HAVE_ARCH_* mechanism?

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

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