Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751242Ab0HSPoe (ORCPT ); Thu, 19 Aug 2010 11:44:34 -0400 Received: from mx1.sophos.com ([195.166.81.52]:48571 "EHLO mx1.sophos.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120Ab0HSPod convert rfc822-to-8bit (ORCPT ); Thu, 19 Aug 2010 11:44:33 -0400 From: Tvrtko Ursulin Organization: Sophos Plc To: Andreas Schwab Subject: Re: struct fanotify_event_metadata Date: Thu, 19 Aug 2010 16:44:29 +0100 User-Agent: KMail/1.13.5 (Linux/2.6.34-12-desktop; KDE/4.4.4; x86_64; ; ) CC: Andreas Gruenbacher , Eric Paris , "linux-kernel@vger.kernel.org" References: In-Reply-To: MIME-Version: 1.0 Message-ID: <201008191644.29299.tvrtko.ursulin@sophos.com> X-MIMETrack: Itemize by SMTP Server on Mercury/Servers/Sophos(Release 7.0.3|September 26, 2007) at 19/08/2010 16:44:29, Serialize by Router on Mercury/Servers/Sophos(Release 7.0.3|September 26, 2007) at 19/08/2010 16:44:30, Serialize complete at 19/08/2010 16:44:30 X-TNEFEvaluated: 1 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1154 Lines: 26 On Saturday 14 Aug 2010 18:44:38 Andreas Schwab wrote: > The pid field of struct fanotify_event_metadata has 64 bits which looks > excessive. Wouldn't it make sense to make it 32 bits and swap it with > the mask field? That would avoid the unaligned mask field, and remove > the need for the packed attribute. No one seems to have picked up on this what I thought was an obvious good idea. So yes, 32-bit PID makes sense I think. If that was changed, would removing the packed attribute get us anything more? If not it may stay for extra safety if/when new fields are added. Also, would it make sense to move mask in front of fd so 32-bit pid can stay at the end? I think mask logically should be higher because is the more meta data, while pid is auxiliary. Tvrtko Sophos Plc, The Pentagon, Abingdon Science Park, Abingdon, OX14 3YP, United Kingdom. Company Reg No 2096520. VAT Reg No GB 348 3873 20. -- 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/