From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932330AbeCORkU (ORCPT ); Thu, 15 Mar 2018 13:40:20 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39546 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752152AbeCORkS (ORCPT ); Thu, 15 Mar 2018 13:40:18 -0400 Date: Thu, 15 Mar 2018 10:39:59 -0700 From: Ram Pai To: Dave Hansen Cc: Thomas Gleixner , mingo@redhat.com, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de, fweimer@redhat.com, msuchanek@suse.com, Ulrich.Weigand@de.ibm.com Subject: Re: [PATCH v3] x86: treat pkey-0 special Reply-To: Ram Pai References: <1521061214-22385-1-git-send-email-linuxram@us.ibm.com> <20180315172129.GD1060@ram.oc3035372033.ibm.com> <2bf8e659-5a8d-a2d5-ea52-e4d395ea2201@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2bf8e659-5a8d-a2d5-ea52-e4d395ea2201@intel.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 18031517-0040-0000-0000-000004216384 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18031517-0041-0000-0000-000026246DE3 Message-Id: <20180315173959.GE1060@ram.oc3035372033.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-15_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803150193 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 15, 2018 at 10:31:51AM -0700, Dave Hansen wrote: > On 03/15/2018 10:21 AM, Ram Pai wrote: > > On Thu, Mar 15, 2018 at 08:55:31AM -0700, Dave Hansen wrote: > >> On 03/15/2018 02:46 AM, Thomas Gleixner wrote: > >>>> + if (!pkey || !mm_pkey_is_allocated(mm, pkey)) > >>> Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true > >>> ever. If it does, then this wants to be fixed. > >> I was thinking that we _do_ actually want it to seem allocated. It just > >> get "allocated" implicitly when an mm is created. I think that will > >> simplify the code if we avoid treating it specially in as many places as > >> possible. > > I think, the logic that makes pkey-0 special must to go > > in arch-neutral code. How about checking for pkey-0 in sys_pkey_free() > > itself? > > This is for protection against shooting yourself in the foot? Yes, that > can go in sys_pkey_free(). > > Does this need manpage and/or selftests updates? Yes. it needs selftest, manpage and documentation updates too. Unfortunately I am not getting enough reviewed-by for my selftests and documentation changes. :-( Need help! -- Ram Pai