From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Stone Subject: Re: [RfC PATCH] Add udmabuf misc device Date: Fri, 6 Apr 2018 10:52:21 +0100 Message-ID: References: <20180313154826.20436-1-kraxel@redhat.com> <20180313161035.GL4788@phenom.ffwll.local> <20180314080301.366zycak3whqvvqx@sirius.home.kraxel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20180314080301.366zycak3whqvvqx@sirius.home.kraxel.org> Sender: linux-kernel-owner@vger.kernel.org To: Gerd Hoffmann Cc: dri-devel , Tomeu Vizoso , David Airlie , open list , qemu-devel@nongnu.org, "moderated list:DMA BUFFER SHARING FRAMEWORK" , "open list:DMA BUFFER SHARING FRAMEWORK" List-Id: dri-devel@lists.freedesktop.org Hi Gerd, On 14 March 2018 at 08:03, Gerd Hoffmann wrote: >> Either mlock account (because it's mlocked defacto), and get_user_pages >> won't do that for you. >> >> Or you write the full-blown userptr implementation, including mmu_notifi= er >> support (see i915 or amdgpu), but that also requires Christian K=C3=B6ni= gs >> latest ->invalidate_mapping RFC for dma-buf (since atm exporting userptr >> buffers is a no-go). > > I guess I'll look at mlock accounting for starters then. Easier for > now, and leaves the door open to switch to userptr later as this should > be transparent to userspace. Out of interest, do you have usecases for full userptr support? Maybe another way would be to allow creation of dmabufs from memfds. Cheers, Daniel