diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index cd1285c3bfe9..dcf5c0af7de9 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -1177,16 +1177,20 @@ int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
 			return retval;
 		switch (arg) {
 		case TCOOFF:
+			spin_lock_irq(&tty->flow_lock);
 			if (!tty->flow_stopped) {
 				tty->flow_stopped = 1;
-				stop_tty(tty);
+				__stop_tty(tty);
 			}
+			spin_unlock_irq(&tty->flow_lock);
 			break;
 		case TCOON:
+			spin_lock_irq(&tty->flow_lock);
 			if (tty->flow_stopped) {
 				tty->flow_stopped = 0;
-				start_tty(tty);
+				__start_tty(tty);
 			}
+			spin_unlock_irq(&tty->flow_lock);
 			break;
 		case TCIOFF:
 			if (STOP_CHAR(tty) != __DISABLED_CHAR)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index fd4148d3a261..d80b53642f2c 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -262,8 +262,9 @@ struct tty_struct {
 	unsigned long flags;
 	int count;
 	struct winsize winsize;		/* winsize_mutex */
-	int stopped;			/* flow_lock */
-	int flow_stopped;
+	unsigned long stopped:1,	/* flow_lock */
+		      flow_stopped:1,
+		      unused:62;
 	int hw_stopped;
 	int packet;
 	unsigned char ctrl_status;	/* ctrl_lock */