Re: [RFC/PATCH] mm: Pass virtual address to [__]p{te, ud, md}_free_tlb()

On Tue, Jul 28, 2009 at 10:17:40AM +1000, Benjamin Herrenschmidt wrote:

On Mon, 2009-07-27 at 12:11 -0700, Linus Torvalds wrote:

quoted

On Thu, 23 Jul 2009, Benjamin Herrenschmidt wrote:

quoted

Hrm... my powerpc-next branch will contain stuff that depend on it, so
I'll probably have to pull it in though, unless I tell all my
sub-maintainers to also pull from that other branch first :-)

Ok, I'll just apply the patch. It does look obvious enough.

There seem to be a MIPS and SH breakage as a result but I can't see
how my patch would have broken it, ie, it looks like the bug was
already in those two archs. The error is that it complains about a
duplicate definition of __pmd_free_tlb() between those arch pgalloc.h
and pgtable-nopmd.h

For MIPS, when CONFIG_32BIT is set, asm/pgalloc.h redefines
__pmd_free_tlb despite the fact that it's already defined by
asm-generic/pgtable-nopmd.h (via via pgtable.h via linux/mm.h).

I -suspect- what happens is that the compiler, before, would ignore the
double definition (or maybe just warn) due to the definition being
strictly identical. With the new argument added, it's no longer the case
as it's called "a" in asm-generic and "addr" in mips... oops.

In any case, can Ralf and Paul check if the following patch is correct ?

Yup, that seems to be what happened. I've never seen a warning about this
with any compiler version, otherwise we would have caught this much
earlier. As soon as the addr -> a rename took place it blew up
immediately as a redefinition. Is there a magical gcc flag we can turn on
to warn on identical definitions, even if just for testing?

quoted

From 41928c7945d855ae0eb053eadad590ab6876847e Mon Sep 17 00:00:00 2001

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Tue, 28 Jul 2009 10:16:48 +1000
Subject: [PATCH] mm: Remove duplicate definitions in MIPS and SH

Those definitions are already provided by asm-generic

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Builds and boots fine, thanks.

Acked-by: Paul Mundt <redacted>