From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669Ab2ACO0S (ORCPT ); Tue, 3 Jan 2012 09:26:18 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:51801 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752792Ab2ACO0O convert rfc822-to-8bit (ORCPT ); Tue, 3 Jan 2012 09:26:14 -0500 Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes To: linux-kernel@vger.kernel.org, "Gilad Ben-Yossef" Cc: "David Airlie" , dri-devel@lists.freedesktop.org, "Benjamin Herrenschmidt" , "Paul Mackerras" , "Grant Likely" , "Rob Herring" , linuxppc-dev@lists.ozlabs.org, devicetree-discuss@lists.ozlabs.org, "Richard Henderson" , "Ivan Kokshaysky" , "Matt Turner" , linux-alpha@vger.kernel.org, "Thomas Gleixner" , "Ingo Molnar" , "H. Peter Anvin" , x86@kernel.org, "Tony Luck" , "Fenghua Yu" , linux-ia64@vger.kernel.org, "Will Deacon" , "Peter Zijlstra" , "Arnaldo Carvalho de Melo" , "Russell King" , linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH 0/9] Remove useless on_each_cpu return value References: <1325600353-10895-1-git-send-email-gilad@benyossef.com> Date: Tue, 03 Jan 2012 15:25:49 +0100 MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT From: "Michal Nazarewicz" Message-ID: In-Reply-To: <1325600353-10895-1-git-send-email-gilad@benyossef.com> User-Agent: Opera Mail/11.60 (Linux) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 03 Jan 2012 15:19:04 +0100, Gilad Ben-Yossef wrote: > on_each_cpu() returns as its own return value the return value of > smp_call_function(). smp_call_function() in turn returns a hard > coded value of zero. > > Some callers to on_each_cpu() waste cycles and bloat code space > by checking the return value to on_each_cpu(), probably for > historical reasons. > > This patch set refactors callers to not test on_each_cpu() > (fixed) return value and then refactors on_each_cpu to > return void to avoid confusing future users. > > In other words, this patch aims to delete 18 source code lines > while not changing any functionality :-) > > I tested as best as I could the x86 changes and compiled some > of the others, but I don't have access to all the needed hardware > for testing. Reviewers and testers welcome! Other then the lack of Signed-off-by in the patches, looks good to me, even though personally I'd choose a bottom-up approach, ie. make smp_call_function() return void and from that conclude that on_each_cpu() can return void. With those patches, we have a situation, where smp_call_function() has a return value which is then lost for no immediately apparent reason lost in on_each_cpu(). -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +------------------ooO--(_)--Ooo--