Add attribute warn_unused_result to compiler.h and dt_expand_node

This would have thrown a compiler warning for cf8def9 rather than
failing at runtime.

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

2 files changed, 3 insertions, 1 deletions

diff --git a/include/compiler.h b/include/compiler.h
index ab6e28ea..35bf1652 100644
--- a/include/compiler.h
+++ b/include/compiler.h
@@ -30,6 +30,7 @@
 #define __noreturn		__attribute__((noreturn))
 /* not __const as this has a different meaning (const) */
 #define __attrconst		__attribute__((const))
+#define __warn_unused_result	__attribute__((warn_unused_result))
 
 #if 0 /* Provided by gcc stddef.h */
 #define offsetof(type,m)	__builtin_offsetof(type,m)
diff --git a/include/device.h b/include/device.h
index 65ceef45..16c26bb0 100644
--- a/include/device.h
+++ b/include/device.h
@@ -18,6 +18,7 @@
 #define __DEVICE_H
 #include <ccan/list/list.h>
 #include <ccan/short_types/short_types.h>
+#include <compiler.h>
 
 /* Any property or node with this prefix will not be passed to the kernel. */
 #define DT_PRIVATE	"skiboot,"
@@ -187,7 +188,7 @@ void dt_free(struct dt_node *node);
 
 /* Parse an initial fdt */
 void dt_expand(const void *fdt);
-int dt_expand_node(struct dt_node *node, const void *fdt, int fdt_node);
+int dt_expand_node(struct dt_node *node, const void *fdt, int fdt_node) __warn_unused_result;
 
 /* Simplified accessors */
 u64 dt_prop_get_u64(const struct dt_node *node, const char *prop);