From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f179.google.com (mail-qc0-f179.google.com [209.85.216.179]) by kanga.kvack.org (Postfix) with ESMTP id 3DFE36B0031 for ; Fri, 4 Apr 2014 02:54:12 -0400 (EDT) Received: by mail-qc0-f179.google.com with SMTP id m20so3018404qcx.24 for ; Thu, 03 Apr 2014 23:54:11 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id di5si3140225qcb.20.2014.04.03.23.54.09 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Apr 2014 23:54:09 -0700 (PDT) Date: Thu, 3 Apr 2014 23:53:53 -0700 From: Christoph Hellwig Subject: Re: [PATCH] mm: msync: require either MS_ASYNC or MS_SYNC Message-ID: <20140404065353.GA22039@infradead.org> References: <533B04A9.6090405@bbn.com> <20140402111032.GA27551@infradead.org> <1396439119.2726.29.camel@menhir> <533CA0F6.2070100@bbn.com> <533DC357.1080203@bbn.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <533DC357.1080203@bbn.com> Sender: owner-linux-mm@kvack.org List-ID: To: Richard Hansen Cc: mtk.manpages@gmail.com, Steven Whitehouse , Christoph Hellwig , "linux-mm@kvack.org" , lkml , Linux API , Greg Troxel , Peter Zijlstra Guys, I don't really see why you get so worked up about this. There is lots and lots of precedent of Linux allowing non-Posix (or non-standard in general) arguments to system calls. Even ones that don't have symbolic names defined for them (the magic 3 open argument for device files). Given that we historicaly allowed the 0 argument to msync we'll have to keep supporting it to not break existing userspace, and adding warnings triggered by userspace that the person running the system usually can't fix for something that is entirely harmless at runtime isn't going to win you friends either. A "strictly Posix" environment that catches all this sounds fine to me, but it's something that should in the userspace c runtime, not the kernel. The kernel has never been about strict Posix implementations, it sometimes doesn't even make it easy to implement the semantics in user land, which is a bit unfortunate. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org