media: v4l2: Make colorspace validity checks more future-proof

The helper functions that test validity of colorspace-related fields
use the last value of the corresponding enums. This isn't very
future-proof, as there's a high chance someone adding a new value may
forget to update the helpers. Add new "LAST" entries to the enumerations
to improve this, and keep them private to the kernel.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

include/media/v4l2-common.h

@@ -563,19 +563,19 @@ static inline void v4l2_buffer_set_timestamp(struct v4l2_buffer *buf,
 static inline bool v4l2_is_colorspace_valid(__u32 colorspace)
 {
 	return colorspace > V4L2_COLORSPACE_DEFAULT &&
-	       colorspace <= V4L2_COLORSPACE_DCI_P3;
+	       colorspace < V4L2_COLORSPACE_LAST;
 }
 
 static inline bool v4l2_is_xfer_func_valid(__u32 xfer_func)
 {
 	return xfer_func > V4L2_XFER_FUNC_DEFAULT &&
-	       xfer_func <= V4L2_XFER_FUNC_SMPTE2084;
+	       xfer_func < V4L2_XFER_FUNC_LAST;
 }
 
 static inline bool v4l2_is_ycbcr_enc_valid(__u8 ycbcr_enc)
 {
 	return ycbcr_enc > V4L2_YCBCR_ENC_DEFAULT &&
-	       ycbcr_enc <= V4L2_YCBCR_ENC_SMPTE240M;
+	       ycbcr_enc < V4L2_YCBCR_ENC_LAST;
 }
 
 static inline bool v4l2_is_hsv_enc_valid(__u8 hsv_enc)

include/uapi/linux/videodev2.h

@@ -245,6 +245,14 @@ enum v4l2_colorspace {
 
 	/* DCI-P3 colorspace, used by cinema projectors */
 	V4L2_COLORSPACE_DCI_P3        = 12,
+
+#ifdef __KERNEL__
+	/*
+	 * Largest supported colorspace value, assigned by the compiler, used
+	 * by the framework to check for invalid values.
+	 */
+	V4L2_COLORSPACE_LAST,
+#endif
 };
 
 /*
@@ -283,6 +291,13 @@ enum v4l2_xfer_func {
 	V4L2_XFER_FUNC_NONE        = 5,
 	V4L2_XFER_FUNC_DCI_P3      = 6,
 	V4L2_XFER_FUNC_SMPTE2084   = 7,
+#ifdef __KERNEL__
+	/*
+	 * Largest supported transfer function value, assigned by the compiler,
+	 * used by the framework to check for invalid values.
+	 */
+	V4L2_XFER_FUNC_LAST,
+#endif
 };
 
 /*
@@ -343,6 +358,13 @@ enum v4l2_ycbcr_encoding {
 
 	/* SMPTE 240M -- Obsolete HDTV */
 	V4L2_YCBCR_ENC_SMPTE240M      = 8,
+#ifdef __KERNEL__
+	/*
+	 * Largest supported encoding value, assigned by the compiler, used by
+	 * the framework to check for invalid values.
+	 */
+	V4L2_YCBCR_ENC_LAST,
+#endif
 };
 
 /*