diff --git a/[refs] b/[refs]
index 529bb0de2858..c0a008cd581e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3400001c531d283068a60e9f884f7de6f22314be
+refs/heads/master: 56d936607408d71c4141b2ed501410b072f1e211
diff --git a/trunk/include/linux/iommu-helper.h b/trunk/include/linux/iommu-helper.h
index a6d0586e2bf7..3b068e5b5671 100644
--- a/trunk/include/linux/iommu-helper.h
+++ b/trunk/include/linux/iommu-helper.h
@@ -23,4 +23,7 @@ extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
 extern void iommu_area_free(unsigned long *map, unsigned long start,
 			    unsigned int nr);
 
+extern unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
+				     unsigned long io_page_size);
+
 #endif
diff --git a/trunk/lib/iommu-helper.c b/trunk/lib/iommu-helper.c
index 5d90074dca75..75dbda03f4fb 100644
--- a/trunk/lib/iommu-helper.c
+++ b/trunk/lib/iommu-helper.c
@@ -79,3 +79,12 @@ void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
 	}
 }
 EXPORT_SYMBOL(iommu_area_free);
+
+unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
+			      unsigned long io_page_size)
+{
+	unsigned long size = (addr & (io_page_size - 1)) + len;
+
+	return DIV_ROUND_UP(size, io_page_size);
+}
+EXPORT_SYMBOL(iommu_num_pages);