From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754419Ab2LLBm1 (ORCPT ); Tue, 11 Dec 2012 20:42:27 -0500 Received: from www.hansjkoch.de ([178.63.77.200]:50646 "EHLO www.hansjkoch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753616Ab2LLBm0 (ORCPT ); Tue, 11 Dec 2012 20:42:26 -0500 Date: Wed, 12 Dec 2012 02:42:22 +0100 From: "Hans J. Koch" To: Greg KH Cc: Benedikt Spranger , linux-kernel@vger.kernel.org, hjk@hansjkoch.de, Alexander.Frank@eberspaecher.com Subject: Re: [PATCH 2/2] uio: do not expose inode to uio open/release hooks Message-ID: <20121212014221.GA2642@local> References: <1355267523-19724-1-git-send-email-b.spranger@linutronix.de> <1355267523-19724-3-git-send-email-b.spranger@linutronix.de> <20121211232032.GA24933@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121211232032.GA24933@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 11, 2012 at 03:20:32PM -0800, Greg KH wrote: > On Wed, Dec 12, 2012 at 12:12:02AM +0100, Benedikt Spranger wrote: > > The inode parameter is unused by in kernel users of UIO. > > Ok. > > > Also the inode parameter makes it hard to resolve the existing open(), > > mmap() and close() difficulty. > > I don't understand, what do you mean by this? What is this parameter > causing problems with? The problem is that according to POSIX, it is guaranteed that in userspace you can do fd = open("/dev/uio0", ...) ptr = mmap(...fd...) close(fd) with ptr still being valid and useable after that. Thanks, Hans