+#ifndef __HAVE_ARCH_STRNSTR
+/**
+ * strnstr - Find the first substring in a length-limited string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ * @len: the maximum number of characters to search
+ */
+char *strnstr(const char *s1, const char *s2, size_t len)
+{
+ size_t l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ while (len >= l2) {
+ len--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(strnstr);
+#endif
+