From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754131AbdBITi6 (ORCPT ); Thu, 9 Feb 2017 14:38:58 -0500 Received: from aserp1050.oracle.com ([141.146.126.70]:46048 "EHLO aserp1050.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752327AbdBITi4 (ORCPT ); Thu, 9 Feb 2017 14:38:56 -0500 Subject: Re: [Xen-devel] [PATCH 1/3] xen/privcmd: return -ENOSYS for unimplemented IOCTLs To: Jan Beulich , Paul Durrant References: <1486649866-4869-1-git-send-email-paul.durrant@citrix.com> <1486649866-4869-2-git-send-email-paul.durrant@citrix.com> <589C8D610200007800138429@prv-mh.provo.novell.com> Cc: xen-devel@lists.xenproject.org, Juergen Gross , linux-kernel@vger.kernel.org From: Boris Ostrovsky Message-ID: Date: Thu, 9 Feb 2017 10:26:19 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <589C8D610200007800138429@prv-mh.provo.novell.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserp1040.oracle.com [141.146.126.69] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/09/2017 09:40 AM, Jan Beulich wrote: >>>> On 09.02.17 at 15:17, wrote: >> The code goes so far as to set the default return code to -ENOSYS but >> then overrides this to -EINVAL in the switch() statement's default >> case. > > If you already change this, isn't -ENOTTY the traditional way of > indicating unsupported ioctls? In fact, a while ago David submitted a patch to do just that: https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg00744.html but it never went anywhere. My question is whether anyone might be relying on current error return behavior. -boris