diff --git a/include/linux/kstrtox.h b/include/linux/kstrtox.h
index 7fcf29a4e0de..6ea897222af1 100644
--- a/include/linux/kstrtox.h
+++ b/include/linux/kstrtox.h
@@ -143,6 +143,7 @@ static inline int __must_check kstrtos32_from_user(const char __user *s, size_t
  */
 
 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
+extern unsigned long simple_strntoul(const char *,char **,unsigned int,size_t);
 extern long simple_strtol(const char *,char **,unsigned int);
 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 extern long long simple_strtoll(const char *,char **,unsigned int);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 56fe96319292..734bd70c8b9b 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -114,6 +114,13 @@ unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
 }
 EXPORT_SYMBOL(simple_strtoul);
 
+unsigned long simple_strntoul(const char *cp, char **endp, unsigned int base,
+			      size_t max_chars)
+{
+	return simple_strntoull(cp, endp, base, max_chars);
+}
+EXPORT_SYMBOL(simple_strntoul);
+
 /**
  * simple_strtol - convert a string to a signed long
  * @cp: The start of the string