staging: sync: Update new fence status with sync_fence_signal_pt

If a fence's pt is signaled before sync_fence_create is called, the fence
will never transition into the signaled state.  This also address a tiny
race if a merged fence's pt after sync_fence_get_status checks it's status
and before fence->status is updated.

Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: NErik Gilling <konkers@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/sync.c

@@ -295,6 +295,12 @@ struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt)
 	list_add(&pt->pt_list, &fence->pt_list_head);
 	sync_pt_activate(pt);
 
+	/*
+	 * signal the fence in case pt was activated before
+	 * sync_pt_activate(pt) was called
+	 */
+	sync_fence_signal_pt(pt);
+
 	return fence;
 }
 EXPORT_SYMBOL(sync_fence_create);
@@ -457,7 +463,13 @@ struct sync_fence *sync_fence_merge(const char *name,
 	if (err < 0)
 		goto err;
 
-	fence->status = sync_fence_get_status(fence);
+	/*
+	 * signal the fence in case one of it's pts were activated before
+	 * they were activated
+	 */
+	sync_fence_signal_pt(list_first_entry(&fence->pt_list_head,
+					      struct sync_pt,
+					      pt_list));
 
 	return fence;
 err: