From e9fe2aeba2d6174122c167e0617942c86d6ba83b Mon Sep 17 00:00:00 2001
From: Thong Thai <thong.thai@amd.com>
Date: Wed, 8 Apr 2026 15:59:13 +0000
Subject: [PATCH] util: allow for overriding u_stub tail

This commit allows for overriding the normal u_stub's TAIL
implementation (returning -1) with a custom implementation, allowing for
different TAIL implementations to be added without having to create a
new TAIL+ in u_stub.h.

Signed-off-by: Thong Thai <thong.thai@amd.com>
Reviewed-by: David Rosca <david.rosca@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40493>
---
 src/util/u_stub.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/util/u_stub.h b/src/util/u_stub.h
index 9d3a833add4..c6f23650f88 100644
--- a/src/util/u_stub.h
+++ b/src/util/u_stub.h
@@ -11,6 +11,14 @@
  *    #define __U_STUB__
  *    #endif
  *    #include "u_stub.h"
+ * 
+ * To override TAIL, define __U_STUB__TAIL before including u_stub.h, for example:
+ *
+ *    #define __U_STUB__TAIL { return VA_STATUS_ERROR_UNIMPLEMENTED; }
+ *    #ifndef HAVE_XXXX
+ *    #define __U_STUB__
+ *    #endif
+ *    #include "u_stub.h"
  *
  */
 
@@ -24,10 +32,15 @@
 
 #ifdef __U_STUB__
 #define MESAPROC static inline
+
+#ifdef __U_STUB__TAIL
+#define TAIL __U_STUB__TAIL
+#else
 #define TAIL                                                                                       \
    {                                                                                               \
       return -1;                                                                                   \
    }
+#endif
 #define TAILZ                                                                                      \
    {                                                                                               \
       return 0;                                                                                     \