From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 402Fkk0KhQzDr8d for ; Fri, 16 Mar 2018 04:21:49 +1100 (AEDT) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w2FHKkQP105394 for ; Thu, 15 Mar 2018 13:21:47 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 2gqu377c4f-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Thu, 15 Mar 2018 13:21:46 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 15 Mar 2018 17:21:44 -0000 Date: Thu, 15 Mar 2018 10:21:29 -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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Message-Id: <20180315172129.GD1060@ram.oc3035372033.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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? RP