virtio: console: Ensure no memleaks in case of unused buffers

If unused data exists in in_vq, ensure we flush that first and then
detach unused buffers, which will ensure all buffers from the in_vq are
removed.

Also ensure we free the buffers after detaching them.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index a3f1f73..69d2e61 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -838,6 +838,8 @@ static const struct file_operations port_debugfs_ops = {
 /* Remove all port-specific data. */
 static int remove_port(struct port *port)
 {
+       struct port_buffer *buf;
+
        spin_lock_irq(&port->portdev->ports_lock);
        list_del(&port->list);
        spin_unlock_irq(&port->portdev->ports_lock);
@@ -851,14 +853,17 @@ static int remove_port(struct port *port)
        if (port->guest_connected)
                send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 
-       while (port->in_vq->vq_ops->detach_unused_buf(port->in_vq))
-               ;
-
        sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
        device_destroy(pdrvdata.class, port->dev->devt);
        cdev_del(&port->cdev);
 
+       /* Remove unused data this port might have received. */
        discard_port_data(port);
+
+       /* Remove buffers we queued up for the Host to send us data in. */
+       while ((buf = port->in_vq->vq_ops->detach_unused_buf(port->in_vq)))
+               free_buf(buf);
+
        kfree(port->name);
 
        debugfs_remove(port->debugfs_file);