Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753659Ab2JOQkC (ORCPT ); Mon, 15 Oct 2012 12:40:02 -0400 Received: from quartz.orcorp.ca ([184.70.90.242]:48271 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735Ab2JOQkA (ORCPT ); Mon, 15 Oct 2012 12:40:00 -0400 Date: Mon, 15 Oct 2012 10:39:45 -0600 From: Jason Gunthorpe To: Peter.Huewe@infineon.com Cc: key@linux.vnet.ibm.com, tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [tpmdd-devel] [PATCH] TPM: Let the tpm char device be openable multiple times Message-ID: <20121015163945.GA32563@obsidianresearch.com> References: <20120930233345.GJ30637@obsidianresearch.com> <20121010163324.GB5013@ennui.austin.ibm.com> <20121012205658.GM4124@obsidianresearch.com> <74A44E99E3274B4CB570415926B37D440ED140@MUCSE501.eu.infineon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74A44E99E3274B4CB570415926B37D440ED140@MUCSE501.eu.infineon.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.162 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 903 Lines: 20 On Mon, Oct 15, 2012 at 08:35:09AM +0000, Peter.Huewe@infineon.com wrote: > > From: Jason Gunthorpe [mailto:jgunthorpe@obsidianresearch.com] > > > Using open/close is an interesting idea, but it wouldn't work. open() > > is coded to return EBUSY if another process has it open, rather than > > block, and spinning on open would be unacceptable. > > Hmm, maybe write a small pass through program which opens /dev/tpm > once and accepts its data via a socket or pipe? I believe the kernel should not be enforcing this kind of policy into userspace. Plus, some of our embedded system are memory constrained so an unnecessary process is not welcome.. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/