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Commit 88f251ac authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
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virtio: console: Remove cached data on port close 



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: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 431edb8a

drivers/char/virtio_console.c

+40 −0
Original line number Diff line number Diff line
@@ -316,6 +316,31 @@ 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;
@@ -534,8 +559,13 @@ 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;

}
@@ -872,6 +902,16 @@ 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);