From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mundt <lethal@linux-sh.org>
Date: Wed, 06 Oct 2010 18:50:57 +0000
Subject: Re: [PATCH 4/7] ARM: oprofile: Move non-ARM code into separate init/exit
Message-Id: <20101006185057.GB13879@linux-sh.org>
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To: Robert Richter <robert.richter@amd.com>
Cc: Grant Likely <grant.likely@secretlab.ca>, Matt Fleming <matt@console-pimps.org>, Will Deacon <will.deacon@arm.com>, Russell King <linux@arm.linux.org.uk>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>, Frederic Weisbecker <fweisbec@gmail.com>, Arnaldo Carvalho de Melo <acme@redhat.com>, "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Deng-Cheng Zhu <dengcheng.zhu@gmail.com>

On Wed, Oct 06, 2010 at 08:44:07PM +0200, Robert Richter wrote:
> On 06.10.10 14:23:17, Grant Likely wrote:
> > >> diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
> > >> index b336cd9..76d97a5 100644
> > >> --- a/drivers/oprofile/oprof.c
> > >> +++ b/drivers/oprofile/oprof.c
> > >> @@ -252,6 +252,8 @@ static int __init oprofile_init(void)
> > >> ?{
> > >> ? ? ? int err;
> > >>
> > >> + ? ? memset(&oprofile_ops, 0, sizeof(struct oprofile_operations));
> > >> +
> > >
> > > Yes, this looks much better. Thanks Paul.
> > 
> > oprofile_ops is allocated in bss and so is already zeroed.  No need to
> > do it explicitly.
> 
> Before oprofile_arch_init() it isn't necessarily needed, but we should
> definitely add it before oprofile_timer_init(). For code readability I
> would rather tend to let the first in too.
> 
No, it was intentionally not added in between because architectures could
set a backtrace op even if they had no actual counter information to plug
in. oprofile_timer_init() is pretty careful to clear out all of the
unused fields manually, while leaving the backtrace setting untouched.

sh, ia64, and s390 all depend on this behaviour.