virtio_console: move early VQ enablement

Commit f5866db6 (virtio_console: enable VQs early) tried to make
sure that DRIVER_OK was set when virtio_console started using its
virtqueues. Doing this in add_port(), however, means that we try
to set DRIVER_OK again when when a port is dynamically added after
the probe function is done.

Let's move virtio_device_ready() to the probe function just before
trying to use the virtqueues instead. This is fine as nothing can
fail inbetween.
Reported-by: NThomas Graf <tgraf@suug.ch>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

drivers/char/virtio_console.c

@@ -1449,8 +1449,6 @@ static int add_port(struct ports_device *portdev, u32 id)
 	spin_lock_init(&port->outvq_lock);
 	init_waitqueue_head(&port->waitqueue);
 
-	virtio_device_ready(portdev->vdev);
-
 	/* Fill the in_vq with buffers so the host can send us data. */
 	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
 	if (!nr_added_bufs) {
@@ -2026,6 +2024,8 @@ static int virtcons_probe(struct virtio_device *vdev)
 	spin_lock_init(&portdev->ports_lock);
 	INIT_LIST_HEAD(&portdev->ports);
 
+	virtio_device_ready(portdev->vdev);
+
 	if (multiport) {
 		unsigned int nr_added_bufs;