From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756238AbcA2OgE (ORCPT ); Fri, 29 Jan 2016 09:36:04 -0500 Received: from mail-wm0-f44.google.com ([74.125.82.44]:35447 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756190AbcA2OgB (ORCPT ); Fri, 29 Jan 2016 09:36:01 -0500 Date: Fri, 29 Jan 2016 14:35:58 +0000 From: Andy Whitcroft To: Alasdair Kergon , Mike Snitzer , Christoph Hellwig , mohan_srinivasan@yahoo.com, dm-devel@redhat.com, Neil Brown , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Tim Gardner Subject: Re: reinstate dm target local ioctl support Message-ID: <20160129143558.GR9864@bark> References: <1453989019-24300-1-git-send-email-apw@canonical.com> <20160129135712.GA7201@agk-dp.fab.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160129135712.GA7201@agk-dp.fab.redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 29, 2016 at 01:57:12PM +0000, Alasdair G Kergon wrote: > On Thu, Jan 28, 2016 at 01:50:19PM +0000, Andy Whitcroft wrote: > > However this also removed the possibility of a dm target having target > > specific ioctls. Currently this is not used by any in-tree targets but > > was utilised by the flashcache out-of-tree module. > > What data is being passed in and out? > > The method we support is passing it through DM_TARGET_MSG (as text). > For examples look at dm-switch.c and dm-stats.c, which handled > pretty large quantities of data. > > Would that work? That sounds like it has all the bits one would need indeed. I will investigate that. Thanks for the info. -apw