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 for linuxppc-dev@lists.ozlabs.org; Mon, 20 Apr 2015 16:44:58 +0000
Date: Mon, 20 Apr 2015 09:44:31 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: David Miller <davem@davemloft.net>
Subject: Re: sparc64: Build failure due to commit f1600e549b94 (sparc: Make
 sparc64 use scalable lib/iommu-common.c functions)
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On Mon, Apr 20, 2015 at 12:25:19PM -0400, David Miller wrote:
> From: Guenter Roeck <linux@roeck-us.net>
> Date: Sun, 19 Apr 2015 22:17:21 -0700
> 
> > The debug option is intended for all _other_ architectures, to
> > ensure that changes made for those don't break alpha/s390
> > builds. alpha/s390 have ARCH_NEEDS_WEAK_PER_CPU and don't need the
> > debug option.
> 
> Ironically this would not create a build failure for the architectures
> where this matters, because only powerpc has the like named percpu
> symbol.
> 
> So it's not really meeting the stated objective in this case.

Yes, that is correct; it can only find problems in non-architecture
code, and on the downside produces false positives and thus build errors
like this one.

Which makes the fix a bit philosophical. Rename iommu_pool_hash in
iommu-common, or drop DEBUG_FORCE_WEAK_PER_CPU. I would rename
iommu_pool_hash, but that is just me. Ultimately, I don't really
care one way or another, as long as the problem gets fixed.

Guenter