From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753037AbYLRNSp (ORCPT ); Thu, 18 Dec 2008 08:18:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750940AbYLRNSf (ORCPT ); Thu, 18 Dec 2008 08:18:35 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:33498 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750923AbYLRNSf (ORCPT ); Thu, 18 Dec 2008 08:18:35 -0500 Date: Thu, 18 Dec 2008 14:18:12 +0100 From: Ingo Molnar To: Andrew Morton Cc: Jeremy Fitzhardinge , viro@ftp.linux.org.uk, linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, alex.zeffertt@eu.citrix.com, Ian.Campbell@citrix.com Subject: Re: [PATCH UPDATED] xen: add xenfs to allow usermode <-> Xen interaction Message-ID: <20081218131812.GD32135@elte.hu> References: <49480F39.2010102@goop.org> <20081216125425.30524946.akpm@linux-foundation.org> <49496E17.2010703@goop.org> <20081217133429.b64e6421.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081217133429.b64e6421.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > On Wed, 17 Dec 2008 13:24:39 -0800 > Jeremy Fitzhardinge wrote: > > > The xenfs filesystem exports various interfaces to usermode. Initially > > this exports a file to allow usermode to interact with xenbus/xenstore. > > > > Traditionally this appeared in /proc/xen. Rather than extending procfs, > > this patch adds a backward-compat mountpoint on /proc/xen, and provides > > a xenfs filesystem which can be mounted there. > > > > [ > > I did quite a lot of work to this code as a result of review, which is > > why this is a repost rather than a delta. The changes are: > > > > - Moved the XENFS_SUPER_MAGIC to linux/magic.h > > - Added comments to answer the "what's this for?" questions (I hope) > > - Split things out into smaller functions > > - Cleaned up type of queue_reply(), removed casts > > - Added a mutex to protect struct xenbus_file_priv. This protects > > the list heads, and the partial message buffer. There were > > several ways in which usermode could overwrite the kernel's > > memory via races without this locking. > > - Fixed a bug in which usermode could start sending a message > > which can never be sent, leaving the file descriptor in a > > useless state. > > I'm bored of your filesystem, so I think I'll just merge it, unless > someone else wants to ;) please do - there should be no big overlap with existing other Xen bits in tip/*. Ingo