Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753437AbbH0RcU (ORCPT ); Thu, 27 Aug 2015 13:32:20 -0400 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:56369 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbbH0RcS (ORCPT ); Thu, 27 Aug 2015 13:32:18 -0400 X-Sasl-enc: NXZjP5ClmUg7vWIU3JiqgItXn1xu+lNt64R2SW0vGuU9 1440696737 Date: Thu, 27 Aug 2015 14:32:15 -0300 From: Henrique de Moraes Holschuh To: Joe Perches Cc: Darren Hart , ibm-acpi-devel@lists.sourceforge.net, platform-driver-x86@vger.kernel.org, linux-kernel Subject: Re: [PATCH] thinkpad_acpi: Remove side effects from vdbg_printk -> no_printk macro Message-ID: <20150827173215.GA17280@khazad-dum.debian.net> References: <1440612818.2780.24.camel@perches.com> <1440613632.3433387.366841089.60E02F29@webmail.messagingengine.com> <1440614125.2780.33.camel@perches.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1440614125.2780.33.camel@perches.com> X-GPG-Fingerprint1: 4096R/39CB4807 C467 A717 507B BAFE D3C1 6092 0BD9 E811 39CB 4807 X-GPG-Fingerprint2: 1024D/1CDB0FE3 5422 5C61 F6B7 06FB 7E04 3738 EE25 DE3F 1CDB 0FE3 User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2238 Lines: 54 On Wed, 26 Aug 2015, Joe Perches wrote: > On Wed, 2015-08-26 at 15:27 -0300, Henrique de Moraes Holschuh wrote: > > On Wed, Aug 26, 2015, at 15:13, Joe Perches wrote: > > > vdbg_printk when not using CONFIG_THINKPAD_ACPI_DEBUG uses > > > no_printk which produces no logging output but always > > > evaluates arguments. > > > > > > Change the macro to surround the no_printk call with > > > do { if (0) no_printk(...); } while (0) > > > to avoid the unnecessary argument evaluations. > > > > > > $ size drivers/platform/x86/thinkpad_acpi.o* > > > text data bss dec hex filename > > > 60918 6184 824 67926 10956 > > > drivers/platform/x86/thinkpad_acpi.o.new > > > 60927 6184 824 67935 1095f > > > drivers/platform/x86/thinkpad_acpi.o.old > > > > The code size savings of this change are really small... > > yup. This is just an on-the-way patch to get > all the no_printk uses in a state that can > be converted more simply to a side-effect free > mechanism. > > > > --- a/drivers/platform/x86/thinkpad_acpi.c > > > +++ b/drivers/platform/x86/thinkpad_acpi.c > > > @@ -402,7 +402,7 @@ static const char *str_supported(int is_supported); > > > #else > > > static inline const char *str_supported(int is_supported) { return ""; } > > > #define vdbg_printk(a_dbg_level, format, arg...) \ > > > - no_printk(format, ##arg) > > > + do { if (0) no_printk(format, ##arg); } while (0) > > > #endif > > > > And won't this change disable compile-time checking of 'format ## arg' > > for issues? > > No. The call is still there so the compiler checks > the format/argument matches, but eliminates the > call and any side-effect calls from the object file. Ok, very well. In that case, I will ack it. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/