[RFC 3/6] dma-buf/sync_file: add sync_file_fences_get()

Gustavo Padovan
2016-03-23T18:47:43Z

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

Creates a function that given an sync file descriptor returns a
fence_collection containing all fences in the sync_file.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
drivers/dma-buf/sync_file.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/sync_file.h | 8 ++++++++
2 files changed, 44 insertions(+)

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index b67876b..16a3ef7 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -122,6 +122,42 @@ void sync_file_install(struct sync_file *sync_file, int fd)
}
EXPORT_SYMBOL(sync_file_install);

+static void sync_file_fence_collection_put(void *data)
+{
+ struct sync_file *sync_file = data;
+
+ sync_file_put(sync_file);
+}
+
+struct fence_collection *sync_file_fences_get(int fd)
+{
+ struct fence_collection *collection;
+ struct sync_file *sync_file;
+ int i;
+
+ sync_file = sync_file_fdget(fd);
+ if (!sync_file)
+ return NULL;
+
+ collection = kzalloc(offsetof(struct fence_collection,
+ fences[sync_file->num_fences]),
+ GFP_KERNEL);
+ if (!collection)
+ return NULL;
+
+ collection->num_fences = sync_file->num_fences;
+ collection->user_data = sync_file;
+ collection->func = sync_file_fence_collection_put;
+
+ for (i = 0; i < sync_file->num_fences; ++i) {
+ collection->fences[i] = sync_file->cbs[i].fence;
+ fence_get(collection->fences[i]);
+ }
+
+ return collection;
+}
+EXPORT_SYMBOL(sync_file_fences_get);
+
static void sync_file_add_pt(struct sync_file *sync_file, int *i,
struct fence *fence)
{
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index 7b7a89d..1b9386a 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -103,4 +103,12 @@ void sync_file_put(struct sync_file *sync_file);
*/
void sync_file_install(struct sync_file *sync_file, int fd);

+/**
+ * sync_file_fences_get - get the fence collection related to the fd
+ * @fd: file descriptor to look for a fence collection
+ *
+ * Ensures @fd references a valid sync_file, increments the refcount of the
+ * backing file. Returns the fence_collection or NULL in case of error.
+ */
+struct fence_collection *sync_file_fences_get(int fd);
#endif /* _LINUX_SYNC_H */
--
2.5.0