ctcm: suspend has to wait for outstanding I/O

State transition to DEV_STATE_STOPPED indicates all outstanding I/O has
finished. Add wait queue to wait for this state.

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index db054ed..ecac3b2 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -1720,6 +1720,11 @@
 		return 0;
 	netif_device_detach(priv->channel[READ]->netdev);
 	ctcm_close(priv->channel[READ]->netdev);
+	if (!wait_event_timeout(priv->fsm->wait_q,
+	    fsm_getstate(priv->fsm) == DEV_STATE_STOPPED, CTCM_TIME_5_SEC)) {
+		netif_device_attach(priv->channel[READ]->netdev);
+		return -EBUSY;
+	}
 	ccw_device_set_offline(gdev->cdev[1]);
 	ccw_device_set_offline(gdev->cdev[0]);
 	return 0;