diff --git a/drivers/char/ttyprintk.c b/drivers/char/ttyprintk.c
index a1f68af..f228615 100644
--- a/drivers/char/ttyprintk.c
+++ b/drivers/char/ttyprintk.c
@@ -170,7 +170,7 @@
 	.ioctl = tpk_ioctl,
 };
 
-struct tty_port_operations null_ops = { };
+static struct tty_port_operations null_ops = { };
 
 static struct tty_driver *ttyprintk_driver;