Message-Id: <1477597031-5139-7-git-send-email-gustavo@padovan.org>
Date:   Thu, 27 Oct 2016 17:37:11 -0200
From:   Gustavo Padovan <gustavo@...ovan.org>
To:     dri-devel@...ts.freedesktop.org
Cc:     linux-kernel@...r.kernel.org, Daniel Stone <daniels@...labora.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Rob Clark <robdclark@...il.com>,
        Greg Hackmann <ghackmann@...gle.com>,
        John Harrison <John.C.Harrison@...el.com>,
        laurent.pinchart@...asonboard.com, seanpaul@...gle.com,
        marcheu@...gle.com, m.chehab@...sung.com,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Brian Starkey <brian.starkey@....com>,
        Gustavo Padovan <gustavo.padovan@...labora.co.uk>
Subject: [PATCH v6 6/6] drm/fence: add out-fences support

From: Gustavo Padovan <gustavo.padovan@...labora.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

Signed-off-by: Gustavo Padovan <gustavo.padovan@...labora.co.uk>
---
 drivers/gpu/drm/drm_atomic.c | 199 ++++++++++++++++++++++++++++++++++++-------
 drivers/gpu/drm/drm_crtc.c   |   8 ++
 include/drm/drm_atomic.h     |   1 +
 include/drm/drm_crtc.h       |  17 ++++
 4 files changed, 196 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 28d9366..9b70a27 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -290,6 +290,46 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);
 
 /**
+ * drm_atomic_set_out_fence_for_crtc - set CRTC out fence pointer
+ * @state: global atomic state object
+ * @crtc: crtc to set the out fence pointer
+ * @fence_ptr: the userspace pointer to user
+ *
+ * This function stores the out fence pointer in the atomic 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;
+}
+
+/**
+ * drm_atomic_get_out_fence_for_crtc - get CRTC out fence pointer
+ * @state: global atomic state object
+ * @crtc: crtc to set the out fence pointer
+ *
+ * Get the user pointer that should be used for to store the out fence fd.
+ * This function should be called only once per atomic state as it clears
+ * the out_fence_ptr store there to prevent drivers to access them.
+ *
+ * Returns:
+ *
+ * The out fence user pointer.
+ */
+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
  * @mode: kernel-internal mode to use for the CRTC, or NULL to disable
@@ -490,6 +530,12 @@ 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 +578,8 @@ 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 +1554,9 @@ 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 +1566,6 @@ 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 +1670,38 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_clean_old_fb);
 
+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;
+}
+
+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;
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv)
 {
@@ -1649,9 +1716,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 	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;
+	unsigned int i, j, fence_idx = 0;
 
 	/* disallow for drivers not supporting atomic: */
 	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1766,13 +1834,33 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		drm_mode_object_unreference(obj);
 	}
 
+	fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
+			      GFP_KERNEL);
+	if (!fence_state) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
-	if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-		for_each_crtc_in_state(state, crtc, crtc_state, i) {
+	for_each_crtc_in_state(state, crtc, crtc_state, i) {
+
+		fence_state->out_fence_ptr =
+			drm_atomic_get_out_fence_for_crtc(crtc_state->state, crtc);
+
+		if (fence_state->out_fence_ptr &&
+		    (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)) {
+			if (put_user(-1, fence_state->out_fence_ptr)) {
+				ret = -EFAULT;
+				goto out;
+			}
+
+			continue;
+		}
+
+		if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT ||
+		    fence_state->out_fence_ptr) {
 			struct drm_pending_vblank_event *e;
 
-			e = create_vblank_event(dev, file_priv, NULL,
-						arg->user_data);
+			e = create_vblank_event(dev, arg->user_data);
 			if (!e) {
 				ret = -ENOMEM;
 				goto out;
@@ -1780,6 +1868,39 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 
 			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;
+				goto out;
+			}
+		}
+
+		if (fence_state->out_fence_ptr) {
+			struct dma_fence *fence;
+
+			fence = get_crtc_fence(crtc, crtc_state);
+			if (!fence) {
+				ret = -ENOMEM;
+				goto out;
+			}
+
+			ret = setup_out_fence(&fence_state[fence_idx++], fence);
+			if (ret) {
+				dma_fence_put(fence);
+				goto out;
+			}
+
+			crtc_state->event->base.fence = fence;
+		}
 	}
 
 	if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
@@ -1794,24 +1915,44 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		ret = drm_atomic_commit(state);
 	}
 
+	if (ret)
+		goto out;
+
+	for (i = 0; i < fence_idx; 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.
-		 */
-
+	if (ret) {
 		for_each_crtc_in_state(state, crtc, crtc_state, i) {
-			if (!crtc_state->event)
-				continue;
+			/*
+			 * 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);
+		}
 
-			drm_event_cancel_free(dev, &crtc_state->event->base);
+		if (fence_state) {
+			for (i = 0; i < fence_idx; 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");
+			}
 		}
 	}
 
+	kfree(fence_state);
+
 	if (ret == -EDEADLK) {
 		drm_atomic_state_clear(state);
 		drm_modeset_backoff(&ctx);
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 278dbdd..2539394 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -768,6 +768,18 @@ static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
 }
 
 /**
+ * struct drm_out_fence_state - store out_fence data for install and clean up
+ * @out_fence_ptr: user pointer to store the fence fd in.
+ * @sync_file: sync_file related to the out_fence
+ * @fd: file descriptor to installed on the sync_file.
+ */
+struct drm_out_fence_state {
+	u64 __user *out_fence_ptr;
+	struct sync_file *sync_file;
+	int fd;
+};
+
+/*
  * 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
@@ -1245,6 +1257,11 @@ 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.
+	 */
+	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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