Date: Mon, 30 Jun 2008 08:30:30 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Glauber Costa <gcosta@redhat.com>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, x86@kernel.org,
       "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 25/39] merge common parts of uaccess.
Message-ID: <20080630063030.GA31336@elte.hu>
References: <1214602486-17080-17-git-send-email-gcosta@redhat.com> <1214602486-17080-18-git-send-email-gcosta@redhat.com> <1214602486-17080-19-git-send-email-gcosta@redhat.com> <1214602486-17080-20-git-send-email-gcosta@redhat.com> <1214602486-17080-21-git-send-email-gcosta@redhat.com> <1214602486-17080-22-git-send-email-gcosta@redhat.com> <1214602486-17080-23-git-send-email-gcosta@redhat.com> <1214602486-17080-24-git-send-email-gcosta@redhat.com> <1214602486-17080-25-git-send-email-gcosta@redhat.com> <1214602486-17080-26-git-send-email-gcosta@redhat.com>
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* Glauber Costa <gcosta@redhat.com> wrote:

> common parts of uaccess_32.h and uaccess_64.h
> are put in uaccess.h.

-tip testing found that it causes this build failure:

  fs/binfmt_aout.c: Assembler messages:
  fs/binfmt_aout.c:152: Error: suffix or operands invalid for `cmp'

with:

  http://redhat.com/~mingo/misc/config-Mon_Jun_30_08_17_42_CEST_2008.bad

and comparing the 32-bit and unified version is not simple and the 
commit is rather large.

I'm sure the fix is simple, but this bug shows a structural problem with 
this unification patch. The proper way to unify files is to first bring 
both the 32-bit and the 64-bit version up to a unified form via 
finegrained changes, so that uaccess_32.h and uaccess_64.h becomes 
exactly the same file.

... _then_ only, in a final 'mechanic unification' step the two files 
are merged into uaccess.h. (but no change is done to the content)

If anything breaks during such a series it's bisectable to a finegrained 
patch on either the 32-bit or the 64-bit side. If this commit was shaped 
that way i could now report to you the exact bisection result - instead 
of this too-broad bisection result.

So please rework this commit in that fashion (not just to fix this 
breakage but in anticipation of future commits) - uaccess.h is central 
enough for us to be super careful about it.

	Ingo
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