From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753649Ab0JOInO (ORCPT ); Fri, 15 Oct 2010 04:43:14 -0400 Received: from one.firstfloor.org ([213.235.205.2]:48435 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752111Ab0JOInN (ORCPT ); Fri, 15 Oct 2010 04:43:13 -0400 Date: Fri, 15 Oct 2010 10:43:11 +0200 From: Andi Kleen To: Eric Paris Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, jengelh@medozas.de, davem@davemloft.net, andi@firstfloor.org Subject: Re: [PATCH] types.h: define __aligned_u64 and expose to userspace Message-ID: <20101015084311.GA25620@basil.fritz.box> References: <20101015042455.12772.27482.stgit@paris.rdu.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101015042455.12772.27482.stgit@paris.rdu.redhat.com> 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 Fri, Oct 15, 2010 at 12:24:55AM -0400, Eric Paris wrote: > We currently have a kernel internal type called aligned_u64 which aligns > __u64's on 8 bytes boundaries even on systems which would normally align > them on 4 byte boundaries. This patch creates a new type __aligned_u64 > which does the same thing but which is exposed to userspace rather than > being kernel internal. > > Based-on-patch-by: Andreas Gruenbacher > Signed-off-by: Eric Paris Acked-by: Andi Kleen but only if you: > +/* this is a special 64bit data type that is 8-byte aligned */ Expand this comment a bit that that using this type as a replacement for u64 is recommended for any user visible 64bit value in a structure and that it avoids problem with the compat layer on x86-64. -Andi -- ak@linux.intel.com -- Speaking for myself only.