linux-kernel - __packed vs. __attribute__((packed)) in kernel headers

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Message-ID: <20110622063441.GA1740@x4.trippels.de>
Date:	Wed, 22 Jun 2011 08:34:41 +0200
From:	Markus Trippelsdorf <markus@...ppelsdorf.de>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:	Mike Frysinger <vapier@...too.org>,
	Sam Ravnborg <sam@...nborg.org>,
	Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
Subject: __packed vs. __attribute__((packed)) in kernel headers

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 <linux\/compiler.h>//;
 		$line =~ s/(^|\s)(inline)\b/$1__$2__/g;
 		$line =~ s/(^|\s)(asm)\b(\s|[(]|$)/$1__$2__$3/g;

Any thoughts?

-- 
Markus
--
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