From: Gustavo Padovan <gustavo.pado...@collabora.co.uk>

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

Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
---
 drivers/gpu/drm/drm_atomic.c | 233 +++++++++++++++++++++++++++++++++++--------
 drivers/gpu/drm/drm_crtc.c   |   8 ++
 include/drm/drm_atomic.h     |   1 +
 include/drm/drm_crtc.h       |   7 +-
 4 files changed, 206 insertions(+), 43 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index d1ae463..9a7d84c 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -289,6 +289,25 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);

+static void
+drm_atomic_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 *
+drm_atomic_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;
+}
+
 /**
  * drm_atomic_set_mode_for_crtc - set mode for CRTC
  * @state: the CRTC whose incoming state to update
@@ -490,6 +509,12 @@ 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) {
+               uint64_t __user *fence_ptr = u64_to_user_ptr(val);
+               if (!access_ok(VERIFY_WRITE, fence_ptr, sizeof(*fence_ptr)))
+                       return -EFAULT;
+
+               drm_atomic_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
@@ -532,6 +557,8 @@ 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
@@ -1506,11 +1533,9 @@ EXPORT_SYMBOL(drm_atomic_nonblocking_commit);
  */

 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)
@@ -1520,17 +1545,6 @@ 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;
 }

@@ -1635,6 +1649,148 @@ 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 drm_crtc_state *crtc_state)
+{
+       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 {
+       u64 __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)
+{
+       struct drm_crtc *crtc;
+       struct drm_crtc_state *crtc_state;
+       int i, ret, fence_idx = 0;
+
+       for_each_crtc_in_state(state, crtc, crtc_state, i) {
+               u64 __user *fence_ptr;
+
+               fence_ptr = drm_atomic_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;
+
+                       fence_state[fence_idx].out_fence_ptr = fence_ptr;
+
+                       fence = get_crtc_fence(crtc, crtc_state);
+                       if (!fence)
+                               return -ENOMEM;
+
+                       ret = setup_out_fence(&fence_state[fence_idx], fence);
+                       if (ret) {
+                               dma_fence_put(fence);
+                               return ret;
+                       }
+
+                       fence_idx++;
+
+                       crtc_state->event->base.fence = fence;
+               }
+       }
+
+       return 0;
+}
+
+static void unprepare_crtc_signaling(struct drm_device *dev,
+                                    struct drm_atomic_state *state,
+                                    struct drm_out_fence_state *fence_state)
+{
+       struct drm_crtc *crtc;
+       struct drm_crtc_state *crtc_state;
+       int i;
+
+       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);
+       }
+
+       for (i = 0; fence_state[i].out_fence_ptr; i++) {
+               if (fence_state[i].sync_file)
+                       fput(fence_state[i].sync_file->file);
+               if (fence_state[i].fd >= 0)
+                       put_unused_fd(fence_state[i].fd);
+
+               /* If this fails log error to the user */
+               if (fence_state[i].out_fence_ptr &&
+                   put_user(-1, fence_state[i].out_fence_ptr))
+                       DRM_INFO("Couldn't clear out_fence_ptr\n");
+       }
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
                          void *data, struct drm_file *file_priv)
 {
@@ -1647,8 +1803,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
        struct drm_atomic_state *state;
        struct drm_modeset_acquire_ctx ctx;
        struct drm_plane *plane;
-       struct drm_crtc *crtc;
-       struct drm_crtc_state *crtc_state;
+       struct drm_out_fence_state *fence_state = NULL;
        unsigned plane_mask;
        int ret = 0;
        unsigned int i, j;
@@ -1766,21 +1921,18 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
                drm_mode_object_unreference(obj);
        }

-       if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-               for_each_crtc_in_state(state, crtc, crtc_state, i) {
-                       struct drm_pending_vblank_event *e;
-
-                       e = create_vblank_event(dev, file_priv, NULL,
-                                               arg->user_data);
-                       if (!e) {
-                               ret = -ENOMEM;
-                               goto out;
-                       }
-
-                       crtc_state->event = e;
-               }
+       fence_state = kzalloc(dev->mode_config.num_crtc * sizeof(*fence_state),
+                             GFP_KERNEL);
+       if (!fence_state) {
+               ret = -ENOMEM;
+               goto out;
        }

+       ret = prepare_crtc_signaling(dev, state, arg, file_priv,
+                                         fence_state);
+       if (ret)
+               goto out;
+
        if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
                /*
                 * Unlike commit, check_only does not clean up state.
@@ -1793,23 +1945,20 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
                ret = drm_atomic_commit(state);
        }

+       if (ret)
+               goto out;
+
+       for (i = 0; fence_state[i].sync_file && i < dev->mode_config.num_crtc;
+            i++)
+               fd_install(fence_state[i].fd, fence_state[i].sync_file->file);
+
 out:
        drm_atomic_clean_old_fb(dev, plane_mask, ret);

-       if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-               /*
-                * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
-                * if they weren't, this code should be called on success
-                * for TEST_ONLY too.
-                */
-
-               for_each_crtc_in_state(state, crtc, crtc_state, i) {
-                       if (!crtc_state->event)
-                               continue;
+       if (ret && fence_state)
+               unprepare_crtc_signaling(dev, state, fence_state);

-                       drm_event_cancel_free(dev, &crtc_state->event->base);
-               }
-       }
+       kfree(fence_state);

        if (ret == -EDEADLK) {
                drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index e2a06c8..a18d81b 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -274,6 +274,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, 
struct drm_crtc *crtc,
        if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
                drm_object_attach_property(&crtc->base, config->prop_active, 0);
                drm_object_attach_property(&crtc->base, config->prop_mode_id, 
0);
+               drm_object_attach_property(&crtc->base,
+                                          config->prop_out_fence_ptr, 0);
        }

        return 0;
@@ -434,6 +436,12 @@ static int drm_mode_create_standard_properties(struct 
drm_device *dev)
                return -ENOMEM;
        dev->mode_config.prop_in_fence_fd = prop;

+       prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+                       "OUT_FENCE_PTR", 0, U64_MAX);
+       if (!prop)
+               return -ENOMEM;
+       dev->mode_config.prop_out_fence_ptr = prop;
+
        prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
                        "CRTC_ID", DRM_MODE_OBJECT_CRTC);
        if (!prop)
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 2d1e9c9..ebde60e 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
        struct drm_crtc *ptr;
        struct drm_crtc_state *state;
        struct drm_crtc_commit *commit;
+       u64 __user *out_fence_ptr;
 };

 struct __drm_connnectors_state {
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 30f2401..a5a05e8 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -773,7 +773,7 @@ static inline struct drm_crtc *fence_to_crtc(struct 
dma_fence *fence)
        return container_of(fence->lock, struct drm_crtc, fence_lock);
 }

-/**
+/*
  * struct drm_mode_set - new values for a CRTC config change
  * @fb: framebuffer to use for new config
  * @crtc: CRTC whose configuration we're about to change
@@ -1251,6 +1251,11 @@ struct drm_mode_config {
         */
        struct drm_property *prop_in_fence_fd;
        /**
+        * @prop_out_fence_ptr: Sync File fd pointer representing the
+        * outgoing fences for a CRTC. Userspace should provide a u64 pointer.
+        */
+       struct drm_property *prop_out_fence_ptr;
+       /**
         * @prop_crtc_id: Default atomic plane property to specify the
         * &drm_crtc.
         */
-- 
2.5.5

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