From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933207AbdACEBL (ORCPT ); Mon, 2 Jan 2017 23:01:11 -0500 Received: from mga11.intel.com ([192.55.52.93]:11349 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756478AbdACEBC (ORCPT ); Mon, 2 Jan 2017 23:01:02 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,451,1477983600"; d="scan'208";a="48849183" Date: Tue, 3 Jan 2017 02:57:37 +0200 From: Jarkko Sakkinen To: Jason Gunthorpe Cc: tpmdd-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, Peter Huewe , Marcel Selhorst , open list Subject: Re: [PATCH RFC 1/4] tpm: migrate struct tpm_buf to struct tpm_chip Message-ID: <20170103005737.t2qrc32xzdnvqy4b@intel.com> References: <20170102132213.22880-1-jarkko.sakkinen@linux.intel.com> <20170102132213.22880-2-jarkko.sakkinen@linux.intel.com> <20170102210101.GA5544@obsidianresearch.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170102210101.GA5544@obsidianresearch.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 02, 2017 at 02:01:01PM -0700, Jason Gunthorpe wrote: > On Mon, Jan 02, 2017 at 03:22:07PM +0200, Jarkko Sakkinen wrote: > > Since there is only one thread using TPM chip at a time to transmit data > > we can migrate struct tpm_buf to struct tpm_chip. This makes the use of > > it more fail safe as the buffer is allocated from heap when the device > > is created and not for every transaction. > > Eh? What? I don't think that is the case.. > > We don't serialize until we hit tramsit_cmd at which point the buffer > is already being used and cannot be shared between threads. There is a regression in the patch. All functions that use 'tr_buf' should take tpm_mutex first and use TPM_TRANSMIT_UNLOCKED. There's also a similar regression in TPM space patch that I have to correct. > Why would the resource manager need a single global tpm buffer? That > seems like a big regression from where we have been going. I don't > think this is a good idea to go down this road. What? 'tr_buf' is not specifically for resource manager. This commit makes creating TPM commands more fail-safe because there is no need to allocate page for every transmit. For RM decorations this is really important because I rather would have them fail as rarely as possible. If this would become a scalability issue then the granularity could be reconsidered. > > - tpm_buf_append(buf, (u8 *) &value2, 4); > > + tpm_buf_append(buf, (u8 *)&value2, 4); > > Please try and avoid this sort of churn in patches that change things.. It wasn't there on purpose. I do not know how these slipped. I can clean these up. > Jason /Jarkko