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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 7977FC43381 for ; Tue, 12 Mar 2019 12:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 459CC20657 for ; Tue, 12 Mar 2019 12:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726395AbfCLMgk (ORCPT ); Tue, 12 Mar 2019 08:36:40 -0400 Received: from mga18.intel.com ([134.134.136.126]:20537 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725894AbfCLMgk (ORCPT ); Tue, 12 Mar 2019 08:36:40 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Mar 2019 05:36:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,471,1544515200"; d="scan'208";a="133617532" Received: from skalur-mobl.amr.corp.intel.com (HELO localhost) ([10.249.254.173]) by fmsmga007.fm.intel.com with ESMTP; 12 Mar 2019 05:36:34 -0700 Date: Tue, 12 Mar 2019 14:36:32 +0200 From: Jarkko Sakkinen To: Calvin Owens Cc: Peter Huewe , Jason Gunthorpe , Arnd Bergmann , Greg Kroah-Hartman , linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH] tpm: Make timeout logic simpler and more robust Message-ID: <20190312123632.GB9243@linux.intel.com> References: <358e89ed2b766d51b5f57abf31ab7a925ac63379.1552348123.git.calvinowens@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <358e89ed2b766d51b5f57abf31ab7a925ac63379.1552348123.git.calvinowens@fb.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 11, 2019 at 04:54:04PM -0700, Calvin Owens wrote: > We're having lots of problems with TPM commands timing out, and we're > seeing these problems across lots of different hardware (both v1/v2). > > I instrumented the driver to collect latency data, but I wasn't able to > find any specific timeout to fix: it seems like many of them are too > aggressive. So I tried replacing all the timeout logic with a single > universal long timeout, and found that makes our TPMs 100% reliable. > > Given that this timeout logic is very complex, problematic, and appears > to serve no real purpose, I propose simply deleting all of it. > > Signed-off-by: Calvin Owens Have been thinking about this and I do agree. It has been like that before my times with this subsystem so when I did the original TPM2 patches I carried this logic albeit even at that point I did not get it. Now that I've been maintaining for over three years I'm confident that this the Right Thing to do. /Jarkko