diff --git a/mm/cma.h b/mm/cma.h
index ad61cc6dd439..8485ef893e99 100644
--- a/mm/cma.h
+++ b/mm/cma.h
@@ -36,7 +36,7 @@ struct cma {
 };
 
 extern struct cma cma_areas[MAX_CMA_AREAS];
-extern unsigned cma_area_count;
+extern unsigned int cma_area_count;
 
 static inline unsigned long cma_bitmap_maxno(struct cma *cma)
 {