diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9f274a687c7e908959136b14dcc34d583d2f2b55..451eaa13bc28a765f99b83acb2702ee64690ff76 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -637,9 +637,10 @@ static inline int is_normal_idx(enum zone_type idx)
 static inline int is_highmem(struct zone *zone)
 {
 #ifdef CONFIG_HIGHMEM
-	int zone_idx = zone - zone->zone_pgdat->node_zones;
-	return zone_idx == ZONE_HIGHMEM ||
-		(zone_idx == ZONE_MOVABLE && zone_movable_is_highmem());
+	int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
+	return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
+	       (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
+		zone_movable_is_highmem());
 #else
 	return 0;
 #endif