Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934038Ab1FWRqa (ORCPT ); Thu, 23 Jun 2011 13:46:30 -0400 Received: from ud10.udmedia.de ([194.117.254.50]:37785 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933017Ab1FWRq0 (ORCPT ); Thu, 23 Jun 2011 13:46:26 -0400 Date: Thu, 23 Jun 2011 19:46:23 +0200 From: Markus Trippelsdorf To: richard -rw- weinberger Cc: "linux-kernel@vger.kernel.org" , Mike Frysinger , Sam Ravnborg , Artem Bityutskiy Subject: Re: __packed vs. __attribute__((packed)) in kernel headers Message-ID: <20110623174623.GA1708@x4.trippels.de> References: <20110622063441.GA1740@x4.trippels.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2437 Lines: 53 On 2011.06.23 at 19:04 +0200, richard -rw- weinberger wrote: > On Wed, Jun 22, 2011 at 8:34 AM, Markus Trippelsdorf > wrote: > > A recent commit 3627924acf70a changed __attribute__ ((packed)) to > > __packed in some UBI headers. This breaks the build of busybox: > > > >  CC      miscutils/ubi_attach_detach.o > > In file included from miscutils/ubi_attach_detach.c:27:0: > > /usr/include/mtd/ubi-user.h:330:3: error: conflicting types for ‘__packed’ > > /usr/include/mtd/ubi-user.h:314:3: note: previous declaration of ‘__packed’ was here > > /usr/include/mtd/ubi-user.h:372:3: error: conflicting types for ‘__packed’ > > /usr/include/mtd/ubi-user.h:314:3: note: previous declaration of ‘__packed’ was here > > ... > > > > But this kind of change is suggested by checkpatch.pl: > >  WARN("__packed is preferred over __attribute__((packed))\n > > > > One possible solution would be to let the "scripts/headers_install.pl" > > script automatically substitute __packed with __attribute__((packed)): > > > > diff --git a/scripts/headers_install.pl b/scripts/headers_install.pl > > index efb3be1..e0dc065 100644 > > --- a/scripts/headers_install.pl > > +++ b/scripts/headers_install.pl > > @@ -35,6 +35,7 @@ foreach my $file (@files) { > >                $line =~ s/([\s(])__iomem\s/$1/g; > >                $line =~ s/\s__attribute_const__\s/ /g; > >                $line =~ s/\s__attribute_const__$//g; > > +               $line =~ s/\s__packed/__attribute__((packed))/g; > >                $line =~ s/^#include //; > >                $line =~ s/(^|\s)(inline)\b/$1__$2__/g; > >                $line =~ s/(^|\s)(asm)\b(\s|[(]|$)/$1__$2__$3/g; > > > > Any thoughts? > > > > Hmm, this introduces a new error source. > Whenever we change the definition of __packed we have to > adjust headers_install.pl too. That definition will never change as long as we use gcc. The __packed shortcut was introduced 2007 (commit 82ddcb04057). It's use in the exported header files could cause problems, because the outside world doesn't necessarily know about that shortcut. -- Markus -- 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/