Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756613AbcKKN1w (ORCPT ); Fri, 11 Nov 2016 08:27:52 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:48859 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756069AbcKKN1u (ORCPT ); Fri, 11 Nov 2016 08:27:50 -0500 Date: Fri, 11 Nov 2016 22:27:38 +0900 From: Gustavo Padovan To: Brian Starkey Cc: Gustavo Padovan , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Stone , Daniel Vetter , Rob Clark , Greg Hackmann , John Harrison , laurent.pinchart@ideasonboard.com, seanpaul@google.com, marcheu@google.com, m.chehab@samsung.com, Maarten Lankhorst , Gustavo Padovan Subject: Re: [PATCH v8 3/3] drm/fence: add out-fences support Message-ID: <20161111132738.GL26677@joana> References: <1478841369-20826-1-git-send-email-gustavo@padovan.org> <1478841369-20826-4-git-send-email-gustavo@padovan.org> <20161111114115.GB26660@e106950-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161111114115.GB26660@e106950-lin.cambridge.arm.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10904 Lines: 345 Hi Brian, 2016-11-11 Brian Starkey : > Hi Gustavo, > > On Fri, Nov 11, 2016 at 02:16:09PM +0900, Gustavo Padovan wrote: > > From: Gustavo Padovan > > > > Support DRM out-fences by creating a sync_file with a fence for each CRTC > > that sets the OUT_FENCE_PTR property. > > > > We use the out_fence pointer received in the OUT_FENCE_PTR prop to send > > the sync_file fd back to userspace. > > > > The sync_file and fd are allocated/created before commit, but the > > fd_install operation only happens after we know that commit succeed. > > > > v2: Comment by Rob Clark: > > - Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here. > > > > Comment by Daniel Vetter: > > - Add clean up code for out_fences > > > > v3: Comments by Daniel Vetter: > > - create DRM_MODE_ATOMIC_EVENT_MASK > > - userspace should fill out_fences_ptr with the crtc_ids for which > > it wants fences back. > > > > v4: Create OUT_FENCE_PTR properties and remove old approach. > > > > v5: Comments by Brian Starkey: > > - Remove extra fence_get() in atomic_ioctl() > > - Check ret before iterating on the crtc_state > > - check ret before fd_install > > - set fence_state to NULL at the beginning > > - check fence_state->out_fence_ptr before put_user() > > - change order of fput() and put_unused_fd() on failure > > > > - Add access_ok() check to the out_fence_ptr received > > - Rebase after fence -> dma_fence rename > > - Store out_fence_ptr in the drm_atomic_state > > - Split crtc_setup_out_fence() > > - return -1 as out_fence with TEST_ONLY flag > > > > v6: Comments by Daniel Vetter > > - Add prepare/unprepare_crtc_signaling() > > - move struct drm_out_fence_state to drm_atomic.c > > - mark get_crtc_fence() as static > > > > Comments by Brian Starkey > > - proper set fence_ptr fence_state array > > - isolate fence_idx increment > > > > - improve error handling > > > > v7: Comments by Daniel Vetter > > - remove prefix from internal functions > > - make out_fence_ptr an s64 pointer > > - degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail > > - fix doc issues > > - filter out OUT_FENCE_PTR == NULL and do fail in this case > > Do *not* fail in this case? > > > - add complete_crtc_signalling() > > - krealloc fence_state on demand > > > > Comment by Brian Starkey > > - remove unused crtc_state arg from get_out_fence() > > > > Signed-off-by: Gustavo Padovan > > From an integration with writeback point of view, this looks fine to > me - I can add writeback to this easily. > > A few comments below though: > > > --- > > drivers/gpu/drm/drm_atomic.c | 242 +++++++++++++++++++++++++++++++++++-------- > > drivers/gpu/drm/drm_crtc.c | 8 ++ > > include/drm/drm_atomic.h | 1 + > > include/drm/drm_crtc.h | 6 ++ > > 4 files changed, 212 insertions(+), 45 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c > > index 8e26ad1..cd39f13 100644 > > --- a/drivers/gpu/drm/drm_atomic.c > > +++ b/drivers/gpu/drm/drm_atomic.c > > @@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state, > > } > > EXPORT_SYMBOL(drm_atomic_get_crtc_state); > > > > +static void set_out_fence_for_crtc(struct drm_atomic_state *state, > > + struct drm_crtc *crtc, u64 __user *fence_ptr) > > +{ > > + state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr; > > +} > > + > > +static u64 __user * get_out_fence_for_crtc(struct drm_atomic_state *state, > > + struct drm_crtc *crtc) > > +{ > > + u64 __user *fence_ptr; > > + > > + fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr; > > + state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL; > > + > > + return fence_ptr; > > +} > > + > > You missed a couple of s/u64/s64/ in the two functions above. > > > /** > > * drm_atomic_set_mode_for_crtc - set mode for CRTC > > * @state: the CRTC whose incoming state to update > > @@ -491,6 +508,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc, > > &replaced); > > state->color_mgmt_changed |= replaced; > > return ret; > > + } else if (property == config->prop_out_fence_ptr) { > > + s64 __user *fence_ptr = u64_to_user_ptr(val); > > + > > + if (!fence_ptr) > > + return 0; > > + > > + if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr))) > > + return -EFAULT; > > + > > + set_out_fence_for_crtc(state->state, crtc, fence_ptr); > > } else if (crtc->funcs->atomic_set_property) > > return crtc->funcs->atomic_set_property(crtc, state, property, val); > > else > > @@ -533,6 +560,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc, > > *val = (state->ctm) ? state->ctm->base.id : 0; > > else if (property == config->gamma_lut_property) > > *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0; > > + else if (property == config->prop_out_fence_ptr) > > + *val = 0; > > else if (crtc->funcs->atomic_get_property) > > return crtc->funcs->atomic_get_property(crtc, state, property, val); > > else > > @@ -1659,11 +1688,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor) > > */ > > > > static struct drm_pending_vblank_event *create_vblank_event( > > - struct drm_device *dev, struct drm_file *file_priv, > > - struct dma_fence *fence, uint64_t user_data) > > + struct drm_device *dev, uint64_t user_data) > > { > > struct drm_pending_vblank_event *e = NULL; > > - int ret; > > > > e = kzalloc(sizeof *e, GFP_KERNEL); > > if (!e) > > @@ -1673,17 +1700,6 @@ static struct drm_pending_vblank_event *create_vblank_event( > > e->event.base.length = sizeof(e->event); > > e->event.user_data = user_data; > > > > - if (file_priv) { > > - ret = drm_event_reserve_init(dev, file_priv, &e->base, > > - &e->event.base); > > - if (ret) { > > - kfree(e); > > - return NULL; > > - } > > - } > > - > > - e->base.fence = fence; > > - > > return e; > > } > > > > @@ -1788,6 +1804,166 @@ void drm_atomic_clean_old_fb(struct drm_device *dev, > > } > > EXPORT_SYMBOL(drm_atomic_clean_old_fb); > > > > +static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc) > > +{ > > + struct dma_fence *fence; > > + > > + fence = kzalloc(sizeof(*fence), GFP_KERNEL); > > + if (!fence) > > + return NULL; > > + > > + dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock, > > + crtc->fence_context, ++crtc->fence_seqno); > > + > > + return fence; > > +} > > + > > +struct drm_out_fence_state { > > + s64 __user *out_fence_ptr; > > + struct sync_file *sync_file; > > + int fd; > > +}; > > + > > +static int setup_out_fence(struct drm_out_fence_state *fence_state, > > + struct dma_fence *fence) > > +{ > > + fence_state->fd = get_unused_fd_flags(O_CLOEXEC); > > + if (fence_state->fd < 0) > > + return fence_state->fd; > > + > > + if (put_user(fence_state->fd, fence_state->out_fence_ptr)) > > + return -EFAULT; > > + > > + fence_state->sync_file = sync_file_create(fence); > > + if(!fence_state->sync_file) > > + return -ENOMEM; > > + > > + return 0; > > +} > > + > > +static int prepare_crtc_signaling(struct drm_device *dev, > > + struct drm_atomic_state *state, > > + struct drm_mode_atomic *arg, > > + struct drm_file *file_priv, > > + struct drm_out_fence_state **fence_state, > > + unsigned int *num_fences) > > +{ > > + struct drm_crtc *crtc; > > + struct drm_crtc_state *crtc_state; > > + int i, ret; > > + > > + for_each_crtc_in_state(state, crtc, crtc_state, i) { > > + u64 __user *fence_ptr; > > + > > + fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc); > > + > > + if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY && fence_ptr) { > > + if (put_user(-1, fence_ptr)) > > + return -EFAULT; > > + > > + continue; > > + } > > + > > + if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) { > > + struct drm_pending_vblank_event *e; > > + > > + e = create_vblank_event(dev, arg->user_data); > > + if (!e) > > + return -ENOMEM; > > + > > + crtc_state->event = e; > > + } > > + > > + if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) { > > + struct drm_pending_vblank_event *e = crtc_state->event; > > + > > + if (!file_priv) > > + continue; > > + > > + ret = drm_event_reserve_init(dev, file_priv, &e->base, > > + &e->event.base); > > + if (ret) { > > + kfree(e); > > + crtc_state->event = NULL; > > + return ret; > > + } > > + } > > + > > + if (fence_ptr) { > > + struct dma_fence *fence; > > + struct drm_out_fence_state *f; > > + > > + f = krealloc(*fence_state, sizeof(**fence_state) * > > + (*num_fences + 1), GFP_KERNEL); > > + if (!f) > > + return -ENOMEM; > > + > > + f[*num_fences].out_fence_ptr = fence_ptr; > > + > > + fence = get_crtc_fence(crtc); > > + if (!fence) > > + return -ENOMEM; > > + > > + ret = setup_out_fence(&f[*num_fences], fence); > > + if (ret) { > > + dma_fence_put(fence); > > + return ret; > > + } > > Looks to me that the cleanup path doesn't work here. If > setup_out_fence fails, you bail out before incrementing num_fences, > and so the cleanup loop will be an iteration short. > > > + > > + (*num_fences)++; > > + > > + *fence_state = f; > > I think this is problematic too. If I understand krealloc right, when > you bail out before here and f != *fence_state, then the old > *fence_state will have been already freed, and f is going to leak. Yes, it is broken, I missed that. I think for fence_state I can just move the assignment a few lines above and for num_fences one way is to increment it before returning on error. > > > + crtc_state->event->base.fence = fence; > > + } > > + } > > + > > + return 0; > > +} > > + > > +static void complete_crtc_signaling(struct drm_device *dev, > > + struct drm_atomic_state *state, > > + struct drm_out_fence_state *fence_state, > > + unsigned int num_fences, int ret) > > +{ > > + struct drm_crtc *crtc; > > + struct drm_crtc_state *crtc_state; > > + int i; > > + > > + if (!ret) { > > + for (i = 0; i < num_fences; i++) > > + fd_install(fence_state[i].fd, > > + fence_state[i].sync_file->file); > > + return; > > + } > > + > > + if (!fence_state) > > + return; > > + > > + for_each_crtc_in_state(state, crtc, crtc_state, i) { > > + /* > > + * TEST_ONLY and PAGE_FLIP_EVENT are mutually > > + * exclusive, if they weren't, this code should be > > + * called on success for TEST_ONLY too. > > + */ > > + if (crtc_state->event) > > + drm_event_cancel_free(dev, &crtc_state->event->base); > > + } > > I think this event cleanup needs to be before the !fence_state check; > userspace can ask for events but no fences, and if that fails then the > events need to be freed. Yes. In the previous version this was the correct flow, but with v8 the clean up actually needs to happen before. Gustavo