1 files changed, 67 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 884a17275b3a..112c130cfaaa 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -891,4 +891,71 @@ static inline int i915_gem_object_userptr_validate(struct drm_i915_gem_object *o
 
 #endif
 
+/**
+ * i915_gem_object_get_frontbuffer - Get the object's frontbuffer
+ * @obj: The object whose frontbuffer to get.
+ *
+ * Get pointer to object's frontbuffer if such exists. Please note that RCU
+ * mechanism is used to handle e.g. ongoing removal of frontbuffer pointer.
+ *
+ * Return: pointer to object's frontbuffer is such exists or NULL
+ */
+static inline struct intel_frontbuffer *
+i915_gem_object_get_frontbuffer(const struct drm_i915_gem_object *obj)
+{
+	struct intel_frontbuffer *front;
+
+	if (likely(!rcu_access_pointer(obj->frontbuffer)))
+		return NULL;
+
+	rcu_read_lock();
+	do {
+		front = rcu_dereference(obj->frontbuffer);
+		if (!front)
+			break;
+
+		if (unlikely(!kref_get_unless_zero(&front->ref)))
+			continue;
+
+		if (likely(front == rcu_access_pointer(obj->frontbuffer)))
+			break;
+
+		intel_frontbuffer_put(front);
+	} while (1);
+	rcu_read_unlock();
+
+	return front;
+}
+
+/**
+ * i915_gem_object_set_frontbuffer - Set the object's frontbuffer
+ * @obj: The object whose frontbuffer to set.
+ * @front: The frontbuffer to set
+ *
+ * Set object's frontbuffer pointer. If frontbuffer is already set for the
+ * object keep it and return it's pointer to the caller. Please note that RCU
+ * mechanism is used to handle e.g. ongoing removal of frontbuffer pointer. This
+ * function is protected by i915->display.fb_tracking.lock
+ *
+ * Return: pointer to frontbuffer which was set.
+ */
+static inline struct intel_frontbuffer *
+i915_gem_object_set_frontbuffer(struct drm_i915_gem_object *obj,
+				struct intel_frontbuffer *front)
+{
+	struct intel_frontbuffer *cur = front;
+
+	if (!front) {
+		RCU_INIT_POINTER(obj->frontbuffer, NULL);
+	} else if (rcu_access_pointer(obj->frontbuffer)) {
+		cur = rcu_dereference_protected(obj->frontbuffer, true);
+		kref_get(&cur->ref);
+	} else {
+		drm_gem_object_get(intel_bo_to_drm_bo(obj));
+		rcu_assign_pointer(obj->frontbuffer, front);
+	}
+
+	return cur;
+}
+
 #endif