[PATCH v6 6/6] staging/android: add flags member to sync ioctl structs

[Gustavo Padovan <gustavo@padovan.org>]

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

Play safe and add flags member to all structs. So we don't need to
break API or create new IOCTL in the future if new features that requires
flags arises.

v2: check if flags are valid (zero, in this case)

v3: return -EINVAL if flags are not zero'ed

v4: add padding for 64-bit alignment

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
 drivers/staging/android/sync.c      | 8 ++++++++
 drivers/staging/android/uapi/sync.h | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c
index 3604e453..e635e6e 100644
--- a/drivers/staging/android/sync.c
+++ b/drivers/staging/android/sync.c
@@ -445,6 +445,11 @@ static long sync_file_ioctl_merge(struct sync_file *sync_file,
 		goto err_put_fd;
 	}
 
+	if (data.flags) {
+		err = -EINVAL;
+		goto err_put_fd;
+	}
+
 	fence2 = sync_file_fdget(data.fd2);
 	if (!fence2) {
 		err = -ENOENT;
@@ -504,6 +509,9 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
 	if (copy_from_user(&in, (void __user *)arg, sizeof(in)))
 		return -EFAULT;
 
+	if (in.flags || in.pad)
+		return -EINVAL;
+
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;
diff --git a/drivers/staging/android/uapi/sync.h b/drivers/staging/android/uapi/sync.h
index f064923..4b4d079 100644
--- a/drivers/staging/android/uapi/sync.h
+++ b/drivers/staging/android/uapi/sync.h
@@ -19,11 +19,13 @@
  * @name:	name of new fence
  * @fd2:	file descriptor of second fence
  * @fence:	returns the fd of the new fence to userspace
+ * @flags:	merge_data flags
  */
 struct sync_merge_data {
 	char	name[32];
 	__s32	fd2;
 	__s32	fence;
+	__u32	flags;
 };
 
 /**
@@ -31,12 +33,14 @@ struct sync_merge_data {
  * @obj_name:		name of parent sync_timeline
  * @driver_name:	name of driver implementing the parent
  * @status:		status of the fence 0:active 1:signaled <0:error
+ * @flags:		fence_info flags
  * @timestamp_ns:	timestamp of status change in nanoseconds
  */
 struct sync_fence_info {
 	char	obj_name[32];
 	char	driver_name[32];
 	__s32	status;
+	__u32	flags;
 	__u64	timestamp_ns;
 };
 
@@ -44,14 +48,18 @@ struct sync_fence_info {
  * struct sync_file_info - data returned from fence info ioctl
  * @name:	name of fence
  * @status:	status of fence. 1: signaled 0:active <0:error
+ * @flags:	sync_file_info flags
  * @num_fences	number of fences in the sync_file
+ * @pad		padding for 64-bit alignment, should always be zero
  * @sync_fence_info: pointer to array of structs sync_fence_info with all
  *		 fences in the sync_file
  */
 struct sync_file_info {
 	char	name[32];
 	__s32	status;
+	__u32	flags;
 	__u32	num_fences;
+	__u32	pad;
 
 	__u64	sync_fence_info;
 };
-- 
2.5.0