Remove any data that we might have in a port's inbuf when closing a port
or when any data is received when a port is closed.
Signed-off-by: Amit Shah <amit.shah@xxxxxxxxxx>
---
drivers/char/virtio_console.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 7154224..0be5562 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -325,6 +325,31 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
return ret;
}
+/* Discard any unread data this port has. Callers lockers. */
+static void discard_port_data(struct port *port)
+{
+ struct port_buffer *buf;
+ struct virtqueue *vq;
+ unsigned int len;
+
+ vq = port->in_vq;
+ if (port->inbuf)
+ buf = port->inbuf;
+ else
+ buf = vq->vq_ops->get_buf(vq, &len);
+
+ if (!buf)
+ return;
+
+ if (add_inbuf(vq, buf) < 0) {
+ buf->len = buf->offset = 0;
+ dev_warn(port->dev, "Error adding buffer back to vq\n");
+ return;
+ }
+
+ port->inbuf = NULL;
+}
+
static bool port_has_data(struct port *port)
{
unsigned long flags;
@@ -554,8 +579,13 @@ static int port_fops_release(struct inode *inode, struct file *filp)
/* Notify host of port being closed */
send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
+ spin_lock_irq(&port->inbuf_lock);
port->guest_connected = false;
+ discard_port_data(port);
+
+ spin_unlock_irq(&port->inbuf_lock);
+
return 0;
}
@@ -904,6 +934,16 @@ static void in_intr(struct virtqueue *vq)
spin_lock_irqsave(&port->inbuf_lock, flags);
port->inbuf = get_inbuf(port);
+ /*
+ * Don't queue up data when port is closed. This condition
+ * can be reached when a console port is not yet connected (no
+ * tty is spawned) and the host sends out data to console
+ * ports. For generic serial ports, the host won't
+ * (shouldn't) send data till the guest is connected.
+ */
+ if (!port->guest_connected)
+ discard_port_data(port);
+
spin_unlock_irqrestore(&port->inbuf_lock, flags);
wake_up_interruptible(&port->waitqueue);
--
1.6.2.5
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