1 files changed, 22 insertions, 1 deletions
diff --git a/tools/include/linux/err.h b/tools/include/linux/err.h
index abf0478a8fb2..332b983ead1e 100644
--- a/tools/include/linux/err.h
+++ b/tools/include/linux/err.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __TOOLS_LINUX_ERR_H
 #define __TOOLS_LINUX_ERR_H
 
@@ -19,7 +20,7 @@
  * Userspace note:
  * The same principle works for userspace, because 'error' pointers
  * fall down to the unused hole far from user space, as described
- * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
+ * in Documentation/arch/x86/x86_64/mm.rst for x86_64 arch:
  *
  * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
  * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
@@ -51,4 +52,24 @@ static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
 	return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
 }
 
+static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
+{
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	else
+		return 0;
+}
+
+/**
+ * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
+ * @ptr: The pointer to cast.
+ *
+ * Explicitly cast an error-valued pointer to another pointer type in such a
+ * way as to make it clear that's what's going on.
+ */
+static inline void * __must_check ERR_CAST(__force const void *ptr)
+{
+	/* cast away the const */
+	return (void *) ptr;
+}
 #endif /* _LINUX_ERR_H */