[RFC 2/6] dma-buf/fence: add struct fence_collection

[Gustavo Padovan]

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

The struct aggregates fences that we need to wait on before proceed with
some specific operation. In DRM, for example, we may wait for a group of
fences to signal before we scanout the buffers related to those fences.

Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
---
 include/linux/fence.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/fence.h b/include/linux/fence.h
index 605bd88..3d1151f 100644
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -104,6 +104,22 @@ struct fence_cb {
 	fence_func_t func;
 };
 
+typedef void (*collection_put_func_t)(void *data);
+
+/**
+ * struct fence_collection - aggregate fences together
+ * @num_fences: number of fence in the collection.
+ * @user_data: user data.
+ * @func: user callback to put user data.
+ * @fences: array of @num_fences fences.
+ */
+struct fence_collection {
+	int num_fences;
+	void *user_data;
+	collection_put_func_t func;
+	struct fence *fences[];
+};
+
 /**
  * struct fence_ops - operations implemented for fence
  * @get_driver_name: returns the driver name.
-- 
2.5.0