[RFC 14/29] dma-buf/fence: create fence_default_release()

[Gustavo Padovan <gustavo@padovan.org>]

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Add a default .release() op to be used on fence_ops vtable.
It removes the fences from any list it was added, removes a timeline ref
and free the fence.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
 drivers/dma-buf/fence.c        | 28 ++++++++++++++++++++++++++++
 drivers/staging/android/sync.c | 18 +-----------------
 include/linux/fence.h          |  1 +
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c
index 51b77ed..e17397d 100644
--- a/drivers/dma-buf/fence.c
+++ b/drivers/dma-buf/fence.c
@@ -544,6 +544,34 @@ out:
 }
 EXPORT_SYMBOL(fence_default_wait);
 
+/**
+ * fence_default_release - default .release op
+ * @fence:	[in]	the fence to release
+ *
+ * This function removes the fence from the child_list * and active_list
+ * (if it was active) and drops its timeline ref. Finally it frees the
+ * fence.
+ */
+void fence_default_release(struct fence *fence)
+{
+	struct fence_timeline *timeline = fence_parent(fence);
+	unsigned long flags;
+
+	if (!timeline)
+		return;
+
+	spin_lock_irqsave(fence->lock, flags);
+	list_del(&fence->child_list);
+	if (!list_empty(&fence->active_list))
+		list_del(&fence->active_list);
+
+	spin_unlock_irqrestore(fence->lock, flags);
+
+	fence_timeline_put(timeline);
+	fence_free(fence);
+}
+EXPORT_SYMBOL(fence_default_release);
+
 static bool
 fence_test_signaled_any(struct fence **fences, uint32_t count)
 {
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c
index 87fb93c..6cddec9 100644
--- a/drivers/staging/android/sync.c
+++ b/drivers/staging/android/sync.c
@@ -335,22 +335,6 @@ static const char *sync_fence_get_timeline_name(struct fence *fence)
 	return parent->name;
 }
 
-static void sync_fence_release(struct fence *fence)
-{
-	struct fence_timeline *parent = fence_parent(fence);
-	unsigned long flags;
-
-	spin_lock_irqsave(fence->lock, flags);
-	list_del(&fence->child_list);
-	if (!list_empty(&fence->active_list))
-		list_del(&fence->active_list);
-
-	spin_unlock_irqrestore(fence->lock, flags);
-
-	fence_timeline_put(parent);
-	fence_free(fence);
-}
-
 static bool sync_fence_signaled(struct fence *fence)
 {
 	struct fence_timeline *parent = fence_parent(fence);
@@ -404,7 +388,7 @@ static const struct fence_ops sync_fence_ops = {
 	.enable_signaling = fence_default_enable_signaling,
 	.signaled = sync_fence_signaled,
 	.wait = fence_default_wait,
-	.release = sync_fence_release,
+	.release = fence_default_release,
 	.fill_driver_data = sync_fence_fill_driver_data,
 	.fence_value_str = sync_fence_value_str,
 	.timeline_value_str = sync_fence_timeline_value_str,
diff --git a/include/linux/fence.h b/include/linux/fence.h
index 73b8c9f..0c97014 100644
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -297,6 +297,7 @@ int fence_signal(struct fence *fence);
 int fence_signal_locked(struct fence *fence);
 bool fence_default_enable_signaling(struct fence *fence);
 signed long fence_default_wait(struct fence *fence, bool intr, signed long timeout);
+void fence_default_release(struct fence *fence);
 int fence_add_callback(struct fence *fence, struct fence_cb *cb,
 		       fence_func_t func);
 bool fence_remove_callback(struct fence *fence, struct fence_cb *cb);
-- 
2.5.0