diff --git a/arch/m68k/mm/kmap.c b/arch/m68k/mm/kmap.c
index c2a38321c96d..3b420f6d8822 100644
--- a/arch/m68k/mm/kmap.c
+++ b/arch/m68k/mm/kmap.c
@@ -89,7 +89,8 @@ static inline void free_io_area(void *addr)
 	for (p = &iolist ; (tmp = *p) ; p = &tmp->next) {
 		if (tmp->addr == addr) {
 			*p = tmp->next;
-			__iounmap(tmp->addr, tmp->size);
+			/* remove gap added in get_io_area() */
+			__iounmap(tmp->addr, tmp->size - IO_SIZE);
 			kfree(tmp);
 			return;
 		}