From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932769Ab0FCIu2 (ORCPT ); Thu, 3 Jun 2010 04:50:28 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:37991 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755646Ab0FCIu0 (ORCPT ); Thu, 3 Jun 2010 04:50:26 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=Jy0kI/JjsyichGZEQxipPGYjjrkUtpCZg/gnZJ6R1JT7GRAZZ+GsiDNi+mDV0IXeHh 4zQKw27uhXDluoOK+Wq29QKt6ie/3lFsJa7I76pMV4dpjexn3yHaWrrcZolDpv9lFc1m 5ZAbMAhH1LO5eEeZx2I4Q3tYFqO+hsRys08pE= Date: Thu, 3 Jun 2010 16:52:48 +0800 From: =?utf-8?Q?Am=C3=A9rico?= Wang To: Eric Dumazet Cc: =?utf-8?Q?Am=C3=A9rico?= Wang , "Eric W. Biederman" , Tetsuo Handa , ebiederm@aristanetworks.com, randy.dunlap@oracle.com, gregkh@suse.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kobject: Suppress compiler warning with gcc 3.x Message-ID: <20100603085248.GC5580@cr0.nay.redhat.com> References: <201006030523.o535NA16029042@www262.sakura.ne.jp> <1275543101.29413.76.camel@edumazet-laptop> <20100603055515.GA5580@cr0.nay.redhat.com> <20100603062314.GB5580@cr0.nay.redhat.com> <1275547587.2456.4.camel@edumazet-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1275547587.2456.4.camel@edumazet-laptop> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 03, 2010 at 08:46:27AM +0200, Eric Dumazet wrote: >Le jeudi 03 juin 2010 à 14:23 +0800, Américo Wang a écrit : >> On Wed, Jun 02, 2010 at 11:02:28PM -0700, Eric W. Biederman wrote: >> >Américo Wang writes: >> > >> >> On Thu, Jun 03, 2010 at 07:31:41AM +0200, Eric Dumazet wrote: >> >>>Le jeudi 03 juin 2010 à 14:23 +0900, Tetsuo Handa a écrit : >> >>>> Gcc 3.x generates a warning >> >>>> >> >>>> include/linux/sysfs.h:183: warning: parameter has incomplete type >> >>>> >> >>>> on each file. >> >>>> Suppress the warning by moving the definition of "enum kobj_ns_type" >> >>>> to before "#include ". >> >>>> >> >>>> Signed-off-by: Tetsuo Handa >> >>> >> >>> >> >>>I was about to submit same patch, but I was also reverting 27eabc7cb4b3 >> >>>(sysfs: Don't use enums in inline function declaration.) >> >>> >> >>>So that sysfs_exit_ns() prototype is consistent regardless of >> >>>CONFIG_SYSFS >> >>> >> >>>What do you think ? >> >>> >> >> >> >> This looks odd, in sysfs.h we do have a forward declaration of >> >> enum kobj_ns_type... I am wondering why gcc 3.x doesn't recognize it. >> > >> >Because the replacement is an inline, and we are passing the enum by value >> >gcc wants to see the full definition, at the point where the inline function >> >is declared. >> > >> >> But sysfs_exit_ns() is not inlined if CONFIG_SYSFS here. >> > > ># gcc -v >Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs >Configured with: ../configure --prefix=/usr --mandir=/usr/share/man >--infodir=/usr/share/info --enable-shared --enable-threads=posix >--disable-checking --with-system-zlib --enable-__cxa_atexit >--disable-libunwind-exceptions --enable-java-awt=gtk >--host=i386-redhat-linux >Thread model: posix >gcc version 3.4.6 20060404 (Red Hat 3.4.6-10) > > ># cat try.c >enum kobj_ns_type; >void sysfs_exit_ns(enum kobj_ns_type type, const void *tag); >int main(int argc, char *argv[]) >{ > return 0; >} ># gcc -O2 -Wall -o try try.c >try.c:2: warning: parameter has incomplete type This sounds like a bug of gcc 3.x, gcc 4.x would complain about it.