diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fd55f725a09ed308305f84c951a4380e392ab318..f6f2c505fa7efd9d5aa34d249f2061515dd30415 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -981,7 +981,7 @@ struct mem_section {
 #endif
 
 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
-#define NR_SECTION_ROOTS	(NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
+#define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
 #define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
 
 #ifdef CONFIG_SPARSEMEM_EXTREME