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Commit 7f5d810d authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
Browse files

virtio: console: Handle port hot-plug 



If the 'nr_ports' variable in the config space is updated to a higher
value, that means new ports have been hotplugged.

Introduce a new workqueue to handle such updates and create new ports.

Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 88f251ac

drivers/char/virtio_console.c

+72 −6
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ struct ports_device { 
	 * notification

	 */

	struct work_struct control_work;

	struct work_struct config_work;



	struct list_head ports;
@@ -675,11 +676,6 @@ static void resize_console(struct port *port) 
	}

}



static void virtcons_apply_config(struct virtio_device *vdev)

{

	resize_console(find_port_by_vtermno(0));

}



/* We set the configuration at this point, since we now have a tty */

static int notifier_add_vio(struct hvc_struct *hp, int data)

{
@@ -928,6 +924,24 @@ static void control_intr(struct virtqueue *vq) 
	schedule_work(&portdev->control_work);

}



static void config_intr(struct virtio_device *vdev)

{

	struct ports_device *portdev;



	portdev = vdev->priv;

	if (use_multiport(portdev)) {

		/* Handle port hot-add */

		schedule_work(&portdev->config_work);

	}

	/*

	 * We'll use this way of resizing only for legacy support.

	 * For newer userspace (VIRTIO_CONSOLE_F_MULTPORT+), use

	 * control messages to indicate console size changes so that

	 * it can be done per-port

	 */

	resize_console(find_port_by_id(portdev, 0));

}



static void fill_queue(struct virtqueue *vq, spinlock_t *lock)

{

	struct port_buffer *buf;
@@ -1040,6 +1054,57 @@ fail: 
	return err;

}



/*

 * The workhandler for config-space updates.

 *

 * This is called when ports are hot-added.

 */

static void config_work_handler(struct work_struct *work)

{

	struct virtio_console_config virtconconf;

	struct ports_device *portdev;

	struct virtio_device *vdev;

	int err;



	portdev = container_of(work, struct ports_device, config_work);



	vdev = portdev->vdev;

	vdev->config->get(vdev,

			  offsetof(struct virtio_console_config, nr_ports),

			  &virtconconf.nr_ports,

			  sizeof(virtconconf.nr_ports));



	if (portdev->config.nr_ports == virtconconf.nr_ports) {

		/*

		 * Port 0 got hot-added.  Since we already did all the

		 * other initialisation for it, just tell the Host

		 * that the port is ready.

		 */

		struct port *port;



		port = find_port_by_id(portdev, 0);

		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);

		return;

	}

	if (virtconconf.nr_ports > portdev->config.max_nr_ports) {

		dev_warn(&vdev->dev,

			 "More ports specified (%u) than allowed (%u)",

			 portdev->config.nr_ports + 1,

			 portdev->config.max_nr_ports);

		return;

	}

	if (virtconconf.nr_ports < portdev->config.nr_ports)

		return;



	/* Hot-add ports */

	while (virtconconf.nr_ports - portdev->config.nr_ports) {

		err = add_port(portdev, portdev->config.nr_ports);

		if (err)

			break;

		portdev->config.nr_ports++;

	}

}



static int init_vqs(struct ports_device *portdev)

{

	vq_callback_t **io_callbacks;
@@ -1230,6 +1295,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) 
	if (multiport) {

		spin_lock_init(&portdev->cvq_lock);

		INIT_WORK(&portdev->control_work, &control_work_handler);

		INIT_WORK(&portdev->config_work, &config_work_handler);



		fill_queue(portdev->c_ivq, &portdev->cvq_lock);

	}
@@ -1266,7 +1332,7 @@ static struct virtio_driver virtio_console = { 
	.driver.owner =	THIS_MODULE,

	.id_table =	id_table,

	.probe =	virtcons_probe,

	.config_changed = virtcons_apply_config,

	.config_changed = config_intr,

};



static int __init init(void)