From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756183AbcA2N5Q (ORCPT ); Fri, 29 Jan 2016 08:57:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43819 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755828AbcA2N5P (ORCPT ); Fri, 29 Jan 2016 08:57:15 -0500 Date: Fri, 29 Jan 2016 13:57:12 +0000 From: Alasdair G Kergon To: Andy Whitcroft Cc: 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: <20160129135712.GA7201@agk-dp.fab.redhat.com> Mail-Followup-To: Andy Whitcroft , 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 References: <1453989019-24300-1-git-send-email-apw@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453989019-24300-1-git-send-email-apw@canonical.com> Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: 64 Baker Street, 4th floor, London, W1U 7DF. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Alasdair