From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758581AbZDWPG7 (ORCPT ); Thu, 23 Apr 2009 11:06:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755170AbZDWPGu (ORCPT ); Thu, 23 Apr 2009 11:06:50 -0400 Received: from one.firstfloor.org ([213.235.205.2]:46708 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754787AbZDWPGt (ORCPT ); Thu, 23 Apr 2009 11:06:49 -0400 Date: Thu, 23 Apr 2009 17:10:24 +0200 From: Andi Kleen To: Johannes Weiner Cc: Andi Kleen , arjan@linux.intel.com, linux-kernel@vger.kernel.org, torvalds@osdl.org, akpm@osdl.org Subject: Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build Message-ID: <20090423151024.GO13896@one.firstfloor.org> References: <20090422221134.GA1753@basil.nowhere.org> <20090423120219.GA23479@cmpxchg.org> <20090423122327.GN13896@one.firstfloor.org> <20090423143859.GA20453@cmpxchg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090423143859.GA20453@cmpxchg.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 23, 2009 at 04:38:59PM +0200, Johannes Weiner wrote: > > +void warn_slowpath_null(const char *file, int line) > > +{ > > + warn_slowpath_fmt(file, line, (const char *) { 0 }); > > +} > > +EXPORT_SYMBOL(warn_slowpath_null); > > I would WTF here without knowing the warning. Can you add a comment? > > Otherwise, Acked-by: Johannes Weiner Ok version with comment. -Andi --- Eliminate thousands of warnings with gcc 3.2 build v3 When building with gcc 3.2 I get thousands of warnings about passing a NULL format string to warn_on_slowpath(). Split this case out into a separate call. This also shrinks the kernel slightly: text data bss dec hex filename 4802274 707668 712704 6222646 5ef336 vmlinux text data bss dec hex filename 4799027 703572 712704 6215303 5ed687 vmlinux v2: Avoid warning in warn_slowpath_null on newer gccs too (J.Weiner) v3: add comment, size numbers Acked-by: Jesper Nilsson Acked-by: Johannes Weiner Signed-off-by: Andi Kleen --- include/asm-generic/bug.h | 7 ++++--- kernel/panic.c | 13 ++++++++++--- 2 files changed, 14 insertions(+), 6 deletions(-) Index: linux-2.6.30-rc2-ak/include/asm-generic/bug.h =================================================================== --- linux-2.6.30-rc2-ak.orig/include/asm-generic/bug.h 2009-01-11 20:20:40.000000000 +0100 +++ linux-2.6.30-rc2-ak/include/asm-generic/bug.h 2009-04-22 23:52:48.000000000 +0200 @@ -58,12 +58,13 @@ */ #ifndef __WARN #ifndef __ASSEMBLY__ -extern void warn_slowpath(const char *file, const int line, +extern void warn_slowpath_fmt(const char *file, const int line, const char *fmt, ...) __attribute__((format(printf, 3, 4))); +extern void warn_slowpath_null(const char *file, const int line); #define WANT_WARN_ON_SLOWPATH #endif -#define __WARN() warn_slowpath(__FILE__, __LINE__, NULL) -#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg) +#define __WARN() warn_slowpath_null(__FILE__, __LINE__) +#define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg) #else #define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0) #endif Index: linux-2.6.30-rc2-ak/kernel/panic.c =================================================================== --- linux-2.6.30-rc2-ak.orig/kernel/panic.c 2009-04-19 19:29:07.000000000 +0200 +++ linux-2.6.30-rc2-ak/kernel/panic.c 2009-04-23 17:05:01.000000000 +0200 @@ -342,7 +342,7 @@ } #ifdef WANT_WARN_ON_SLOWPATH -void warn_slowpath(const char *file, int line, const char *fmt, ...) +void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) { va_list args; char function[KSYM_SYMBOL_LEN]; @@ -358,7 +358,7 @@ if (board) printk(KERN_WARNING "Hardware name: %s\n", board); - if (fmt) { + if (*fmt) { va_start(args, fmt); vprintk(fmt, args); va_end(args); @@ -369,7 +369,14 @@ print_oops_end_marker(); add_taint(TAINT_WARN); } -EXPORT_SYMBOL(warn_slowpath); +EXPORT_SYMBOL(warn_slowpath_fmt); + +void warn_slowpath_null(const char *file, int line) +{ + /* The { 0 } avoids a gcc format warning */ + warn_slowpath_fmt(file, line, (const char *) { 0 }); +} +EXPORT_SYMBOL(warn_slowpath_null); #endif #ifdef CONFIG_CC_STACKPROTECTOR -- ak@linux.intel.com -- Speaking for myself only.