Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753513AbdCMV3s (ORCPT ); Mon, 13 Mar 2017 17:29:48 -0400 Received: from mail-yw0-f193.google.com ([209.85.161.193]:36113 "EHLO mail-yw0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751374AbdCMV3j (ORCPT ); Mon, 13 Mar 2017 17:29:39 -0400 MIME-Version: 1.0 In-Reply-To: <6d3d52ba-29a9-701f-2948-00ce28282975@redhat.com> References: <1488491084-17252-1-git-send-email-labbott@redhat.com> <20170303132949.GC31582@dhcp22.suse.cz> <20170306074258.GA27953@dhcp22.suse.cz> <20170306104041.zghsicrnadoap7lp@phenom.ffwll.local> <20170306105805.jsq44kfxhsvazkm6@sirena.org.uk> <20170306160437.sf7bksorlnw7u372@phenom.ffwll.local> <26bc57ae-d88f-4ea0-d666-2c1a02bf866f@redhat.com> <6d3d52ba-29a9-701f-2948-00ce28282975@redhat.com> From: Rob Clark Date: Mon, 13 Mar 2017 17:29:31 -0400 Message-ID: Subject: Re: [RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging To: Laura Abbott Cc: Daniel Vetter , Benjamin Gaignard , devel@driverdev.osuosl.org, Rom Lemarchand , Linux Kernel Mailing List , Riley Andrews , "dri-devel@lists.freedesktop.org" , Michal Hocko , "linaro-mm-sig@lists.linaro.org" , Linux MM , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Mark Brown , Greg Kroah-Hartman , Daniel Vetter , "linux-arm-kernel@lists.infradead.org" , "linux-media@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 856 Lines: 22 On Mon, Mar 13, 2017 at 5:09 PM, Laura Abbott wrote: >> Hm, we might want to expose all the heaps as individual >> /dev/ion_$heapname nodes? Should we do this from the start, since >> we're massively revamping the uapi anyway (imo not needed, current >> state seems to work too)? >> -Daniel >> > > I thought about that. One advantage with separate /dev/ion_$heap > is that we don't have to worry about a limit of 32 possible > heaps per system (32-bit heap id allocation field). But dealing > with an ioctl seems easier than names. Userspace might be less > likely to hardcode random id numbers vs. names as well. other advantage, I think, is selinux (brought up elsewhere on this thread).. heaps at known fixed PAs are useful for certain sorts of attacks so being able to restrict access more easily seems like a good thing BR, -R