[PATCH 3/3] staging: ipu3-imgu: Add a sanity check for the parameter struct size

[Sakari Ailus <sakari.ailus@linux.intel.com>]

There have been cases where seemingly innocuous patches have broken the
uAPI by changing the memory layout of the parameter struct. Generally such
changes also introduce a change in the size of the entire struct. This
patch adds a sanity check to avoid such cases happening in the future.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/staging/media/ipu3/ipu3-css.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/staging/media/ipu3/ipu3-css.c b/drivers/staging/media/ipu3/ipu3-css.c
index 4f04fe838b0c0..3c700ae9c94e9 100644
--- a/drivers/staging/media/ipu3/ipu3-css.c
+++ b/drivers/staging/media/ipu3/ipu3-css.c
@@ -1911,6 +1911,13 @@ int imgu_css_meta_fmt_set(struct v4l2_meta_format *fmt)
 	switch (fmt->dataformat) {
 	case V4L2_META_FMT_IPU3_PARAMS:
 		fmt->buffersize = sizeof(struct ipu3_uapi_params);
+
+		/*
+		 * Sanity check for the parameter struct size. This must
+		 * not change!
+		 */
+		BUILD_BUG_ON(sizeof(struct ipu3_uapi_params) != 39328);
+
 		break;
 	case V4L2_META_FMT_IPU3_STAT_3A:
 		fmt->buffersize = sizeof(struct ipu3_uapi_stats_3a);
-- 
2.20.1