Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753297AbaDDGyS (ORCPT ); Fri, 4 Apr 2014 02:54:18 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:37772 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752356AbaDDGyK (ORCPT ); Fri, 4 Apr 2014 02:54:10 -0400 Date: Thu, 3 Apr 2014 23:53:53 -0700 From: Christoph Hellwig To: Richard Hansen Cc: mtk.manpages@gmail.com, Steven Whitehouse , Christoph Hellwig , "linux-mm@kvack.org" , lkml , Linux API , Greg Troxel , Peter Zijlstra 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> User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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/