sync: add reference counting to timelines

If a timeline is destroyed while fences still hold pts on it, the reworked
fence release handler can cause the timeline to be freed before all it's points
are freed.

Change-Id: I1cd8ddb638eded7db9db446ff6b37f3dd165d6c4
Signed-off-by: Erik Gilling <konkers@android.com>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
diff --git a/include/linux/sync.h b/include/linux/sync.h
index 00c9bae..15863a6 100644
--- a/include/linux/sync.h
+++ b/include/linux/sync.h
@@ -80,6 +80,7 @@
 
 /**
  * struct sync_timeline - sync object
+ * @kref:		reference count on fence.
  * @ops:		ops that define the implementaiton of the sync_timeline
  * @name:		name of the sync_timeline. Useful for debugging
  * @destoryed:		set when sync_timeline is destroyed
@@ -90,6 +91,7 @@
  * @sync_timeline_list:	membership in global sync_timeline_list
  */
 struct sync_timeline {
+	struct kref		kref;
 	const struct sync_timeline_ops	*ops;
 	char			name[32];