diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index a5e8530a3391..b67dc4974f23 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -56,6 +56,7 @@ struct virtio_ccw_device {
 	unsigned int revision; /* Transport revision */
 	wait_queue_head_t wait_q;
 	spinlock_t lock;
+	struct mutex io_lock; /* Serializes I/O requests */
 	struct list_head virtqueues;
 	unsigned long indicators;
 	unsigned long indicators2;
@@ -296,6 +297,7 @@ static int ccw_io_helper(struct virtio_ccw_device *vcdev,
 	unsigned long flags;
 	int flag = intparm & VIRTIO_CCW_INTPARM_MASK;
 
+	mutex_lock(&vcdev->io_lock);
 	do {
 		spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
 		ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
@@ -308,7 +310,9 @@ static int ccw_io_helper(struct virtio_ccw_device *vcdev,
 		cpu_relax();
 	} while (ret == -EBUSY);
 	wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
-	return ret ? ret : vcdev->err;
+	ret = ret ? ret : vcdev->err;
+	mutex_unlock(&vcdev->io_lock);
+	return ret;
 }
 
 static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
@@ -1253,6 +1257,7 @@ static int virtio_ccw_online(struct ccw_device *cdev)
 	init_waitqueue_head(&vcdev->wait_q);
 	INIT_LIST_HEAD(&vcdev->virtqueues);
 	spin_lock_init(&vcdev->lock);
+	mutex_init(&vcdev->io_lock);
 
 	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
 	dev_set_drvdata(&cdev->dev, vcdev);