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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 4562FC4646D for ; Fri, 10 Aug 2018 19:14:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D580D22450 for ; Fri, 10 Aug 2018 19:14:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D580D22450 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727296AbeHJVqD (ORCPT ); Fri, 10 Aug 2018 17:46:03 -0400 Received: from mga07.intel.com ([134.134.136.100]:23011 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726982AbeHJVqD (ORCPT ); Fri, 10 Aug 2018 17:46:03 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Aug 2018 12:14:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,220,1531810800"; d="scan'208";a="64229057" Received: from bchattar-mobl.amr.corp.intel.com (HELO tstruk-mobl1.jf.intel.com) ([10.252.130.118]) by orsmga008.jf.intel.com with ESMTP; 10 Aug 2018 12:14:33 -0700 Subject: Re: [PATCH v4 2/2] tpm: add support for nonblocking operation To: James Bottomley , Jarkko Sakkinen Cc: flihp@twobit.us, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org References: <153367365951.18015.11320230309813817454.stgit@tstruk-mobl1.jf.intel.com> <153367366969.18015.14742040525393494830.stgit@tstruk-mobl1.jf.intel.com> <20180810174320.GV4692@linux.intel.com> <1533926908.3143.6.camel@HansenPartnership.com> <1533927647.3143.7.camel@HansenPartnership.com> From: Tadeusz Struk Openpgp: preference=signencrypt Autocrypt: addr=tadeusz.struk@intel.com; prefer-encrypt=mutual; keydata= xsDiBEiLICMRBADteQacQxypsuFvAw6IwYzbD8pgQi+kLYBcqfGgVAUN/cO+sLl6u1lVdaDB fhAArdbV9lpoqcWnmhQFTb4A+W569EpydBr6nuatWkEB+fmmx8YoUtuZfXt7v+1l1rc09kaW LY+TkwQkvFCeuvdasgmBLnmRWymEGWi1E12hUgTw/wCgtK24geC7XkiuANMv0gpr+raOgQMD /2yJZ0SeXQApWyTRaeIYN8GgYHZTWuBp/ofN+viEkhrDxahcaGPP5B/Nv6VS1+M0e5m8OzHj qPUbgfyOeJcslC5aoZdqqqzVWVLaA/+Jy+O+6T3k3R/IryVVATldBlwnGFDhET0mKQsd15zt cIdQBBbfSFR5VlugZuWV5q442IpPA/4g7nen9FFPxh45Te8D54hAsOCywjm6xUE0UJGYHeJ/ MXCPtuXfVCbYcOxZVH7kUS2Vtk5d3bF40IE2WnVq1ZScNANF4ZjikxYhYGfNWX3HXak1gSoj UrY87rMSjPIAry4L0BoIx2qgL/k4iV/3QcXL4t5wosU0iw++suf1zGGcKM0gVGFkZXVzeiBT dHJ1ayA8dHN0cnVrQGdtYWlsLmNvbT7CYwQTEQIAIwIbAwYLCQgHAwIEFQIIAwQWAgMBAh4B AheABQJQTjJTAhkBAAoJEDFswfskq9xyqvcAoI2nsaUCX8ZGbu+Jhq+++qlBFJ2rAJ983RoO R2ofHhn3g3Qi4K34tw0l087BTQRauzUlARAAqkWRL/InEPnoGMg/gw/CRaDBaIBgMsvIcghI 7xevIzpleXt6jKHghSBooH+zaT7qi4u2gkgPn4odsER3Rm94XgrZJgoqls6EpKMWpJNGP4HT eYgykhfsZOLX8ijUbjTM/Sm/dZVo6aYoBL2+ciJwyl+Zt3Mp6un3/GWu6cA9005V50pRqO7j PTlVCHi2bedcEEf5DDsYJv/3Oz8/4LpSf6BL6BltjeZVa2y03dTMmD031JTH+OuyJm1yh72Z HWxhlYNXOv6uFJJVr+paQjrAsBVIYKhK24bD+uGJxLm8AN9i7/Si+2YeSsXvKUhk9mIoFBnU VFo63cziRTcpRu/kXgDAbujwN88qytEcvhEZHS6B9vdws+lhTpolEjkLCkz0Y59z4Fs9srKy QkRN+wtdiLgrwyDW3ryAKxcDmOumGWebDxpaOI/pBhrlS93HmDlvj7JmgTUU4a/NhwI3dXh5 pn8FZzZyVXe3Kc3bu5T3UAC7uztinsAvCJQS6jGZWrXmXkqYkaLXQOw61eInWjr01zE/zDbE mdJPM0+va/gtZx9TtGxr4PpjbqswqCiubLDZXZHh5uqArPv/i+E8aXIsNSTN6Rrqs1j9YgDN ALksibv6+tXH3sOlCUgjuZgJH3+s/mnaAtiV2rZ/WlH15d6nd0uiDSZrKhlR+g4NHMh1ztEA EQEAAcJPBBgRAgAPBQJauzUlAhsMBQkJZgGAAAoJEDFswfskq9xyfv8AoI8aPrJCoM0h5WOP kKxMmPEPHzUNAJ9jBBYXhX1CWg+IhI7i/fLlI0vwCA== Message-ID: <468c5651-6883-b6f1-64a4-6c6c2cade6de@intel.com> Date: Fri, 10 Aug 2018 12:14:32 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1533927647.3143.7.camel@HansenPartnership.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/10/2018 12:00 PM, James Bottomley wrote: > On Fri, 2018-08-10 at 11:56 -0700, Tadeusz Struk wrote: >> On 08/10/2018 11:48 AM, James Bottomley wrote: >>> On Fri, 2018-08-10 at 11:21 -0700, Tadeusz Struk wrote: >>>> and the feedback I got from Jason was: >>>> >>>> "I wonder if it is worth creating this when the first file is >>>> opened.. Lots of systems have TPMs but few use the userspace.." >>>> >>>> so I changed this to allocate the WQ on first open. I think it >>>> makes sense, but I leave it to you to decide. >>> >>> If the reason is to not create a wq unless it's needed, shouldn't >>> the condition actually be first open with flag O_NONBLOCK? >>> >> >> Not really because one can do: >> >> int fd = open("/dev/tpm0", O_RDWR); >> fcntl(fd, F_SETFL, O_NONBLOCK); > > so move the condition to first need to queue ... > That would work, even though this is not how this is usually done. The first open looks like the sweet spot between module init and first need to queue. Thanks, -- Tadeusz