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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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Amit Shah 2009-12-21 22:22:08 +05:30 committed by Rusty Russell
parent 88f251ac58
commit 7f5d810dac
1 changed files with 72 additions and 6 deletions
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78
drivers/char/virtio_console.c
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@ -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)