dma-buf/sync_file: refactor fence storage in struct sync_file

Create sync_file->fence to abstract the type of fence we are using for
each sync_file. If only one fence is present we use a normal struct fence
but if there is more fences to be added to the sync_file a fence_array
is created.

This change cleans up sync_file a bit. We don't need to have sync_file_cb
array anymore. Instead, as we always have  one fence, only one fence
callback is registered per sync_file.

v2: Comments from Chris Wilson and Christian König
	- Not using fence_ops anymore
	- fence_is_array() was created to differentiate fence from fence_array
	- fence_array_teardown() is now exported and used under fence_is_array()
	- struct sync_file lost num_fences member

v3: Comments from Chris Wilson and Christian König
	- struct sync_file lost status member in favor of fence_is_signaled()
	- drop use of fence_array_teardown()
	- use sizeof(*fence) to allocate only an array on fence pointers

v4: Comments from Chris Wilson
	- use sizeof(*fence) to reallocate array
	- fix typo in comments
	- protect num_fences sum against overflows
	- use array->base instead of casting the to struct fence

v5: fixes checkpatch warnings

v6: fix case where all fences are signaled.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

1 files changed, 5 insertions, 12 deletions

diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index c6ffe8b0725c..2efc5ec60575 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -19,12 +19,7 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/fence.h>
-
-struct sync_file_cb {
-	struct fence_cb cb;
-	struct fence *fence;
-	struct sync_file *sync_file;
-};
+#include <linux/fence-array.h>
 
 /**
  * struct sync_file - sync file to export to the userspace
@@ -32,10 +27,9 @@ struct sync_file_cb {
  * @kref:		reference count on fence.
  * @name:		name of sync_file.  Useful for debugging
  * @sync_file_list:	membership in global file list
- * @num_fences:		number of sync_pts in the fence
  * @wq:			wait queue for fence signaling
- * @status:		0: signaled, >0:active, <0: error
- * @cbs:		sync_pts callback information
+ * @fence:		fence with the fences in the sync_file
+ * @cb:			fence callback information
  */
 struct sync_file {
 	struct file		*file;
@@ -44,12 +38,11 @@ struct sync_file {
 #ifdef CONFIG_DEBUG_FS
 	struct list_head	sync_file_list;
 #endif
-	int num_fences;
 
 	wait_queue_head_t	wq;
-	atomic_t		status;
 
-	struct sync_file_cb	cbs[];
+	struct fence		*fence;
+	struct fence_cb cb;
 };
 
 struct sync_file *sync_file_create(struct fence *fence);