1 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/err.h b/include/linux/err.h
new file mode 100644
index 0000000..22e5756
--- /dev/null
+++ b/include/linux/err.h
@@ -0,0 +1,59 @@
+#ifndef _LINUX_ERR_H
+#define _LINUX_ERR_H
+
+#include <linux/compiler.h>
+#include <linux/compat.h>
+
+#include <linux/errno.h>
+
+
+/*
+ * Kernel pointers have redundant information, so we can use a
+ * scheme where we can return either an error code or a dentry
+ * pointer with the same return value.
+ *
+ * This should be a per-architecture thing, to allow different
+ * error and pointer decisions.
+ */
+#define MAX_ERRNO	4095
+
+#ifndef __ASSEMBLY__
+
+#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
+
+static inline void *ERR_PTR(long error)
+{
+	return (void *) error;
+}
+
+static inline long PTR_ERR(const void *ptr)
+{
+	return (long) ptr;
+}
+
+static inline long IS_ERR(const void *ptr)
+{
+	return IS_ERR_VALUE((unsigned long)ptr);
+}
+
+static inline bool IS_ERR_OR_NULL(const void *ptr)
+{
+	return !ptr || IS_ERR_VALUE((unsigned long)ptr);
+}
+
+/**
+ * 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
+
+#endif /* _LINUX_ERR_H */