diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 3f3e7a6..b4570b6 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -189,4 +189,10 @@
 
 #endif /* !CONFIG_HUGETLBFS */
 
+#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+					unsigned long len, unsigned long pgoff,
+					unsigned long flags);
+#endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */
+
 #endif /* _LINUX_HUGETLB_H */