1 files changed, 54 insertions, 3 deletions

diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
index 89976da542b1..c00fee539822 100644
--- a/include/drm/drm_syncobj.h
+++ b/include/drm/drm_syncobj.h
@@ -28,6 +28,8 @@
 
 #include "linux/dma-fence.h"
 
+struct drm_syncobj_cb;
+
 /**
  * struct drm_syncobj - sync object.
  *
@@ -43,15 +45,47 @@ struct drm_syncobj {
 	/**
 	 * @fence:
 	 * NULL or a pointer to the fence bound to this object.
+	 *
+	 * This field should not be used directly.  Use drm_syncobj_fence_get
+	 * and drm_syncobj_replace_fence instead.
 	 */
 	struct dma_fence *fence;
 	/**
+	 * @cb_list:
+	 * List of callbacks to call when the fence gets replaced
+	 */
+	struct list_head cb_list;
+	/**
+	 * @lock:
+	 * locks cb_list and write-locks fence.
+	 */
+	spinlock_t lock;
+	/**
 	 * @file:
 	 * a file backing for this syncobj.
 	 */
 	struct file *file;
 };
 
+typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
+				   struct drm_syncobj_cb *cb);
+
+/**
+ * struct drm_syncobj_cb - callback for drm_syncobj_add_callback
+ * @node: used by drm_syncob_add_callback to append this struct to
+ *	  syncobj::cb_list
+ * @func: drm_syncobj_func_t to call
+ *
+ * This struct will be initialized by drm_syncobj_add_callback, additional
+ * data can be passed along by embedding drm_syncobj_cb in another struct.
+ * The callback will get called the next time drm_syncobj_replace_fence is
+ * called.
+ */
+struct drm_syncobj_cb {
+	struct list_head node;
+	drm_syncobj_func_t func;
+};
+
 void drm_syncobj_free(struct kref *kref);
 
 /**
@@ -77,13 +111,30 @@ drm_syncobj_put(struct drm_syncobj *obj)
 	kref_put(&obj->refcount, drm_syncobj_free);
 }
 
+static inline struct dma_fence *
+drm_syncobj_fence_get(struct drm_syncobj *syncobj)
+{
+	struct dma_fence *fence;
+
+	rcu_read_lock();
+	fence = dma_fence_get_rcu_safe(&syncobj->fence);
+	rcu_read_unlock();
+
+	return fence;
+}
+
 struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
 				     u32 handle);
+void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
+			      struct drm_syncobj_cb *cb,
+			      drm_syncobj_func_t func);
+void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
+				 struct drm_syncobj_cb *cb);
 void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
 			       struct dma_fence *fence);
-int drm_syncobj_fence_get(struct drm_file *file_private,
-			  u32 handle,
-			  struct dma_fence **fence);
+int drm_syncobj_find_fence(struct drm_file *file_private,
+			   u32 handle,
+			   struct dma_fence **fence);
 void drm_syncobj_free(struct kref *kref);
 
 #endif