diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h
index 4dd4c04..c975caf 100644
--- a/include/linux/iommu-helper.h
+++ b/include/linux/iommu-helper.h
@@ -1,3 +1,6 @@
+extern int iommu_is_span_boundary(unsigned int index, unsigned int nr,
+				  unsigned long shift,
+				  unsigned long boundary_size);
 extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
 				      unsigned long start, unsigned int nr,
 				      unsigned long shift,