From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751831AbdAWXEx (ORCPT ); Mon, 23 Jan 2017 18:04:53 -0500 Received: from quartz.orcorp.ca ([184.70.90.242]:35366 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750758AbdAWXEv (ORCPT ); Mon, 23 Jan 2017 18:04:51 -0500 Date: Mon, 23 Jan 2017 16:04:33 -0700 From: Jason Gunthorpe To: James Bottomley Cc: linux-security-module@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, open list Subject: Re: [tpmdd-devel] [PATCH RFC v4 4/5] tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c Message-ID: <20170123230433.GC21744@obsidianresearch.com> References: <20170122234438.12102-1-jarkko.sakkinen@linux.intel.com> <20170122234438.12102-5-jarkko.sakkinen@linux.intel.com> <20170123164754.GA29360@obsidianresearch.com> <1485210503.2534.32.camel@HansenPartnership.com> <20170123224952.GA21744@obsidianresearch.com> <1485212231.2534.35.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1485212231.2534.35.camel@HansenPartnership.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.156 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 23, 2017 at 02:57:11PM -0800, James Bottomley wrote: > On Mon, 2017-01-23 at 15:49 -0700, Jason Gunthorpe wrote: > > On Mon, Jan 23, 2017 at 02:28:23PM -0800, James Bottomley wrote: > > > On Mon, 2017-01-23 at 09:47 -0700, Jason Gunthorpe wrote: > > > > On Mon, Jan 23, 2017 at 01:44:32AM +0200, Jarkko Sakkinen wrote: > > > > > From: James Bottomley > > > > > > > > > > Signed-off-by: James Bottomley > > > > > > > > > > > > > I really think we should not use the ugly read/write interface > > > > for > > > > any new things. > > > > > > The R/W interface is needed for backward compat, > > > > With what? This is a new cdev with different semantics. > > If you set TPM_DEVICE=/dev/tpms0 the old software just works. If we > remove the R/W interface, nothing will work. The point being the new > cdev has the same interface semantics, it just has different global > behavour. So you are saying there is so much already deployed TPM2 software that has this TPM_DEVICE env var convention that we need to support it with compat? I'm really surprised by that.. But OK. Can you at least remove the 'user_read_timer' junk from the new cdev? Jason