From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB5F3C10F14 for ; Thu, 3 Oct 2019 12:51:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C03E20700 for ; Thu, 3 Oct 2019 12:51:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730108AbfJCMvG (ORCPT ); Thu, 3 Oct 2019 08:51:06 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42088 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726393AbfJCMvG (ORCPT ); Thu, 3 Oct 2019 08:51:06 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x93ClMeC019848 for ; Thu, 3 Oct 2019 08:51:05 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0b-001b2d01.pphosted.com with ESMTP id 2vdfe1c0f3-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 03 Oct 2019 08:51:04 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 3 Oct 2019 13:50:58 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x93CovpO59375778 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 3 Oct 2019 12:50:57 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 70CC1AE04D; Thu, 3 Oct 2019 12:50:57 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 82A59AE045; Thu, 3 Oct 2019 12:50:55 +0000 (GMT) Received: from localhost.localdomain (unknown [9.85.158.158]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 3 Oct 2019 12:50:55 +0000 (GMT) Subject: Re: [PATCH] tpm: Detach page allocation from tpm_buf From: Mimi Zohar To: Jarkko Sakkinen Cc: James Bottomley , linux-integrity@vger.kernel.org, Jerry Snitselaar , Sumit Garg , Stefan Berger , Peter Huewe , Jason Gunthorpe , Arnd Bergmann , Greg Kroah-Hartman , open list Date: Thu, 03 Oct 2019 08:50:54 -0400 In-Reply-To: <20191003113506.GE8933@linux.intel.com> References: <20190925134842.19305-1-jarkko.sakkinen@linux.intel.com> <1569420226.3642.24.camel@HansenPartnership.com> <20190927130657.GA5556@linux.intel.com> <1570020105.4999.106.camel@linux.ibm.com> <20191003113506.GE8933@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19100312-0016-0000-0000-000002B3AE87 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19100312-0017-0000-0000-00003314B8A6 Message-Id: <1570107054.4421.174.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-10-03_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910030119 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2019-10-03 at 14:35 +0300, Jarkko Sakkinen wrote: > On Wed, Oct 02, 2019 at 08:41:45AM -0400, Mimi Zohar wrote: > > On Fri, 2019-09-27 at 16:06 +0300, Jarkko Sakkinen wrote: > > > On Wed, Sep 25, 2019 at 10:03:46AM -0400, James Bottomley wrote: > > > > On Wed, 2019-09-25 at 16:48 +0300, Jarkko Sakkinen wrote: > > > > [...] > > > > > + data_page = alloc_page(GFP_HIGHUSER); > > > > > + if (!data_page) > > > > > + return -ENOMEM; > > > > > + > > > > > + data_ptr = kmap(data_page); > > > > > > > > I don't think this is such a good idea. On 64 bit it's no different > > > > from GFP_KERNEL and on 32 bit where we do have highmem, kmap space is > > > > at a premium, so doing a highmem allocation + kmap is more wasteful of > > > > resources than simply doing GFP_KERNEL. In general, you should only do > > > > GFP_HIGHMEM if the page is going to be mostly used by userspace, which > > > > really isn't the case here. > > > > > > Changing that in this commit would be wrong even if you are right. > > > After this commit has been applied it is somewhat easier to make > > > best choices for allocation in each call site (probably most will > > > end up using stack). > > > > Agreed, but it could be a separate patch, prior to this one.  Why > > duplicate the problem all over only to change it later? > > What problem exactly it is duplicating? The existing allocation > scheme here works correctly. In the current code "alloc_page(GFP_HIGHUSER)" exists in a single function.  With this patch, "alloc_page(GFP_HIGHUSER)" is duplicated 24 times.  If it is incorrect and we shouldn't be using GFP_HIGHUSER, as James said, then why duplicate it 24 times?  Fix it as a separate patch first, that could be backported if needed, and then make the change. Mimi