Commit message: virtio-console: avoid DMA from stack

put_chars() stuffs the buffer it gets into an sg, but that buffer may be
on the stack. This breaks with CONFIG_VMAP_STACK=y (for me, it
manifested as printks getting turned into NUL bytes).

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
CVE: CVE-2017-8067
CWE: CWE-119
Vulnerability description: drivers/char/virtio_console.c in the Linux kernel 4.9.x and 4.10.x before 4.10.12 interacts incorrectly with the CONFIG_VMAP_STACK option, which allows local users to cause a denial of service (system crash or memory corruption) or possibly have unspecified other impact by leveraging use of more than one virtual page for a DMA scatterlist.

Project: linux
File: virtio_console.c

static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
				  unsigned int event, unsigned int value)
{
	struct scatterlist sg[1];
	struct virtqueue *vq;
	unsigned int len;

	if (!use_multiport(portdev))
		return 0;

	vq = portdev->c_ovq;

	spin_lock(&portdev->c_ovq_lock);

	portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
	portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
	portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);

	sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));

	if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
		virtqueue_kick(vq);
		while (!virtqueue_get_buf(vq, &len)
			&& !virtqueue_is_broken(vq))
			cpu_relax();
	}

	spin_unlock(&portdev->c_ovq_lock);
	return 0;
}

Project: linux
File: virtio_console.c

static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
			      int nents, size_t in_count,
			      void *data, bool nonblock)
{
	struct virtqueue *out_vq;
	int err;
	unsigned long flags;
	unsigned int len;

	out_vq = port->out_vq;

	spin_lock_irqsave(&port->outvq_lock, flags);

	reclaim_consumed_buffers(port);

	err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);

	/* Tell Host to go! */
	virtqueue_kick(out_vq);

	if (err) {
		in_count = 0;
		goto done;
	}

	if (out_vq->num_free == 0)
		port->outvq_full = true;

	if (nonblock)
		goto done;

	/*
	 * Wait till the host acknowledges it pushed out the data we
	 * sent.  This is done for data from the hvc_console; the tty
	 * operations are performed with spinlocks held so we can't
	 * sleep here.  An alternative would be to copy the data to a
	 * buffer and relax the spinning requirement.  The downside is
	 * we need to kmalloc a GFP_ATOMIC buffer each time the
	 * console driver writes something out.
	 */
	while (!virtqueue_get_buf(out_vq, &len)
		&& !virtqueue_is_broken(out_vq))
		cpu_relax();
done:
	spin_unlock_irqrestore(&port->outvq_lock, flags);

	port->stats.bytes_sent += in_count;
	/*
	 * We're expected to return the amount of data we wrote -- all
	 * of it
	 */
	return in_count;
}

Project: linux
File: virtio_console.c

static int add_port(struct ports_device *portdev, u32 id)
{
	char debugfs_name[16];
	struct port *port;
	struct port_buffer *buf;
	dev_t devt;
	unsigned int nr_added_bufs;
	int err;

	port = kmalloc(sizeof(*port), GFP_KERNEL);
	if (!port) {
		err = -ENOMEM;
		goto fail;
	}
	kref_init(&port->kref);

	port->portdev = portdev;
	port->id = id;

	port->name = NULL;
	port->inbuf = NULL;
	port->cons.hvc = NULL;
	port->async_queue = NULL;

	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;

	port->host_connected = port->guest_connected = false;
	port->stats = (struct port_stats) { 0 };

	port->outvq_full = false;

	port->in_vq = portdev->in_vqs[port->id];
	port->out_vq = portdev->out_vqs[port->id];

	port->cdev = cdev_alloc();
	if (!port->cdev) {
		dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
		err = -ENOMEM;
		goto free_port;
	}
	port->cdev->ops = &port_fops;

	devt = MKDEV(portdev->chr_major, id);
	err = cdev_add(port->cdev, devt, 1);
	if (err < 0) {
		dev_err(&port->portdev->vdev->dev,
			"Error %d adding cdev for port %u\n", err, id);
		goto free_cdev;
	}
	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
				  devt, port, "vport%up%u",
				  port->portdev->vdev->index, id);
	if (IS_ERR(port->dev)) {
		err = PTR_ERR(port->dev);
		dev_err(&port->portdev->vdev->dev,
			"Error %d creating device for port %u\n",
			err, id);
		goto free_cdev;
	}

	spin_lock_init(&port->inbuf_lock);
	spin_lock_init(&port->outvq_lock);
	init_waitqueue_head(&port->waitqueue);

	/* Fill the in_vq with buffers so the host can send us data. */
	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
	if (!nr_added_bufs) {
		dev_err(port->dev, "Error allocating inbufs\n");
		err = -ENOMEM;
		goto free_device;
	}

	if (is_rproc_serial(port->portdev->vdev))
		/*
		 * For rproc_serial assume remote processor is connected.
		 * rproc_serial does not want the console port, only
		 * the generic port implementation.
		 */
		port->host_connected = true;
	else if (!use_multiport(port->portdev)) {
		/*
		 * If we're not using multiport support,
		 * this has to be a console port.
		 */
		err = init_port_console(port);
		if (err)
			goto free_inbufs;
	}

	spin_lock_irq(&portdev->ports_lock);
	list_add_tail(&port->list, &port->portdev->ports);
	spin_unlock_irq(&portdev->ports_lock);

	/*
	 * Tell the Host we're set so that it can send us various
	 * configuration parameters for this port (eg, port name,
	 * caching, whether this is a console port, etc.)
	 */
	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);

	if (pdrvdata.debugfs_dir) {
		/*
		 * Finally, create the debugfs file that we can use to
		 * inspect a port's state at any time
		 */
		snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
			 port->portdev->vdev->index, id);
		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
							 pdrvdata.debugfs_dir,
							 port,
							 &port_debugfs_ops);
	}
	return 0;

free_inbufs:
	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
		free_buf(buf, true);
free_device:
	device_destroy(pdrvdata.class, port->dev->devt);
free_cdev:
	cdev_del(port->cdev);
free_port:
	kfree(port);
fail:
	/* The host might want to notify management sw about port add failure */
	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
	return err;
}

Project: linux
File: virtio_console.c

static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
				     int pages)
{
	struct port_buffer *buf;

	reclaim_dma_bufs();

	/*
	 * Allocate buffer and the sg list. The sg list array is allocated
	 * directly after the port_buffer struct.
	 */
	buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
		      GFP_KERNEL);
	if (!buf)
		goto fail;

	buf->sgpages = pages;
	if (pages > 0) {
		buf->dev = NULL;
		buf->buf = NULL;
		return buf;
	}

	if (is_rproc_serial(vq->vdev)) {
		/*
		 * Allocate DMA memory from ancestor. When a virtio
		 * device is created by remoteproc, the DMA memory is
		 * associated with the grandparent device:
		 * vdev => rproc => platform-dev.
		 * The code here would have been less quirky if
		 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
		 * in dma-coherent.c
		 */
		if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
			goto free_buf;
		buf->dev = vq->vdev->dev.parent->parent;

		/* Increase device refcnt to avoid freeing it */
		get_device(buf->dev);
		buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
					      GFP_KERNEL);
	} else {
		buf->dev = NULL;
		buf->buf = kmalloc(buf_size, GFP_KERNEL);
	}

	if (!buf->buf)
		goto free_buf;
	buf->len = 0;
	buf->offset = 0;
	buf->size = buf_size;
	return buf;

free_buf:
	kfree(buf);
fail:
	return NULL;
}

Project: linux
File: virtio_console.c

static void config_intr(struct virtio_device *vdev)
{
	struct ports_device *portdev;

	portdev = vdev->priv;

	if (!use_multiport(portdev))
		schedule_work(&portdev->config_work);
}

Project: linux
File: virtio_console.c

static void config_work_handler(struct work_struct *work)
{
	struct ports_device *portdev;

	portdev = container_of(work, struct ports_device, config_work);
	if (!use_multiport(portdev)) {
		struct virtio_device *vdev;
		struct port *port;
		u16 rows, cols;

		vdev = portdev->vdev;
		virtio_cread(vdev, struct virtio_console_config, cols, &cols);
		virtio_cread(vdev, struct virtio_console_config, rows, &rows);

		port = find_port_by_id(portdev, 0);
		set_console_size(port, rows, cols);

		/*
		 * 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(port);
	}
}

Project: linux
File: virtio_console.c

static void control_intr(struct virtqueue *vq)
{
	struct ports_device *portdev;

	portdev = vq->vdev->priv;
	schedule_work(&portdev->control_work);
}

Project: linux
File: virtio_console.c

static void control_work_handler(struct work_struct *work)
{
	struct ports_device *portdev;
	struct virtqueue *vq;
	struct port_buffer *buf;
	unsigned int len;

	portdev = container_of(work, struct ports_device, control_work);
	vq = portdev->c_ivq;

	spin_lock(&portdev->c_ivq_lock);
	while ((buf = virtqueue_get_buf(vq, &len))) {
		spin_unlock(&portdev->c_ivq_lock);

		buf->len = len;
		buf->offset = 0;

		handle_control_message(vq->vdev, portdev, buf);

		spin_lock(&portdev->c_ivq_lock);
		if (add_inbuf(portdev->c_ivq, buf) < 0) {
			dev_warn(&portdev->vdev->dev,
				 "Error adding buffer to queue\n");
			free_buf(buf, false);
		}
	}
	spin_unlock(&portdev->c_ivq_lock);
}

Project: linux
File: virtio_console.c

static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
			    size_t count, loff_t *offp)
{
	struct port *port;
	char *buf;
	ssize_t ret, out_offset, out_count;

	out_count = 1024;
	buf = kmalloc(out_count, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	port = filp->private_data;
	out_offset = 0;
	out_offset += snprintf(buf + out_offset, out_count,
			       "name: %s\n", port->name ? port->name : "");
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "guest_connected: %d\n", port->guest_connected);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "host_connected: %d\n", port->host_connected);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "outvq_full: %d\n", port->outvq_full);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "bytes_sent: %lu\n", port->stats.bytes_sent);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "bytes_received: %lu\n",
			       port->stats.bytes_received);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "bytes_discarded: %lu\n",
			       port->stats.bytes_discarded);
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "is_console: %s\n",
			       is_console_port(port) ? "yes" : "no");
	out_offset += snprintf(buf + out_offset, out_count - out_offset,
			       "console_vtermno: %u\n", port->cons.vtermno);

	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
	kfree(buf);
	return ret;
}

Project: linux
File: virtio_console.c

static void discard_port_data(struct port *port)
{
	struct port_buffer *buf;
	unsigned int err;

	if (!port->portdev) {
		/* Device has been unplugged.  vqs are already gone. */
		return;
	}
	buf = get_inbuf(port);

	err = 0;
	while (buf) {
		port->stats.bytes_discarded += buf->len - buf->offset;
		if (add_inbuf(port->in_vq, buf) < 0) {
			err++;
			free_buf(buf, false);
		}
		port->inbuf = NULL;
		buf = get_inbuf(port);
	}
	if (err)
		dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
			 err);
}

Project: linux
File: virtio_console.c

static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
{
	struct port_buffer *buf;
	unsigned int nr_added_bufs;
	int ret;

	nr_added_bufs = 0;
	do {
		buf = alloc_buf(vq, PAGE_SIZE, 0);
		if (!buf)
			break;

		spin_lock_irq(lock);
		ret = add_inbuf(vq, buf);
		if (ret < 0) {
			spin_unlock_irq(lock);
			free_buf(buf, true);
			break;
		}
		nr_added_bufs++;
		spin_unlock_irq(lock);
	} while (ret > 0);

	return nr_added_bufs;
}

Project: linux
File: virtio_console.c

static struct port *find_port_by_devt(dev_t dev)
{
	struct ports_device *portdev;
	struct port *port;
	unsigned long flags;

	spin_lock_irqsave(&pdrvdata_lock, flags);
	list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
		port = find_port_by_devt_in_portdev(portdev, dev);
		if (port)
			goto out;
	}
	port = NULL;
out:
	spin_unlock_irqrestore(&pdrvdata_lock, flags);
	return port;
}

Project: linux
File: virtio_console.c

static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
						 dev_t dev)
{
	struct port *port;
	unsigned long flags;

	spin_lock_irqsave(&portdev->ports_lock, flags);
	list_for_each_entry(port, &portdev->ports, list) {
		if (port->cdev->dev == dev) {
			kref_get(&port->kref);
			goto out;
		}
	}
	port = NULL;
out:
	spin_unlock_irqrestore(&portdev->ports_lock, flags);

	return port;
}

Project: linux
File: virtio_console.c

static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
{
	struct port *port;
	unsigned long flags;

	spin_lock_irqsave(&portdev->ports_lock, flags);
	list_for_each_entry(port, &portdev->ports, list)
		if (port->id == id)
			goto out;
	port = NULL;
out:
	spin_unlock_irqrestore(&portdev->ports_lock, flags);

	return port;
}

Project: linux
File: virtio_console.c

static struct port *find_port_by_vtermno(u32 vtermno)
{
	struct port *port;
	struct console *cons;
	unsigned long flags;

	spin_lock_irqsave(&pdrvdata_lock, flags);
	list_for_each_entry(cons, &pdrvdata.consoles, list) {
		if (cons->vtermno == vtermno) {
			port = container_of(cons, struct port, cons);
			goto out;
		}
	}
	port = NULL;
out:
	spin_unlock_irqrestore(&pdrvdata_lock, flags);
	return port;
}

Project: linux
File: virtio_console.c

static void __exit fini(void)
{
	reclaim_dma_bufs();

	unregister_virtio_driver(&virtio_console);
	unregister_virtio_driver(&virtio_rproc_serial);

	class_destroy(pdrvdata.class);
	debugfs_remove_recursive(pdrvdata.debugfs_dir);
}

Project: linux
File: virtio_console.c

static int get_chars(u32 vtermno, char *buf, int count)
{
	struct port *port;

	/* If we've not set up the port yet, we have no input to give. */
	if (unlikely(early_put_chars))
		return 0;

	port = find_port_by_vtermno(vtermno);
	if (!port)
		return -EPIPE;

	/* If we don't have an input queue yet, we can't get input. */
	BUG_ON(!port->in_vq);

	return fill_readbuf(port, (__force char __user *)buf, count, false);
}

Project: linux
File: virtio_console.c

static void handle_control_message(struct virtio_device *vdev,
				   struct ports_device *portdev,
				   struct port_buffer *buf)
{
	struct virtio_console_control *cpkt;
	struct port *port;
	size_t name_size;
	int err;

	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);

	port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
	if (!port &&
	    cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
		/* No valid header at start of buffer.  Drop it. */
		dev_dbg(&portdev->vdev->dev,
			"Invalid index %u in control packet\n", cpkt->id);
		return;
	}

	switch (virtio16_to_cpu(vdev, cpkt->event)) {
	case VIRTIO_CONSOLE_PORT_ADD:
		if (port) {
			dev_dbg(&portdev->vdev->dev,
				"Port %u already added\n", port->id);
			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
			break;
		}
		if (virtio32_to_cpu(vdev, cpkt->id) >=
		    portdev->max_nr_ports) {
			dev_warn(&portdev->vdev->dev,
				"Request for adding port with "
				"out-of-bound id %u, max. supported id: %u\n",
				cpkt->id, portdev->max_nr_ports - 1);
			break;
		}
		add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
		break;
	case VIRTIO_CONSOLE_PORT_REMOVE:
		unplug_port(port);
		break;
	case VIRTIO_CONSOLE_CONSOLE_PORT:
		if (!cpkt->value)
			break;
		if (is_console_port(port))
			break;

		init_port_console(port);
		complete(&early_console_added);
		/*
		 * Could remove the port here in case init fails - but
		 * have to notify the host first.
		 */
		break;
	case VIRTIO_CONSOLE_RESIZE: {
		struct {
			__u16 rows;
			__u16 cols;
		} size;

		if (!is_console_port(port))
			break;

		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
		       sizeof(size));
		set_console_size(port, size.rows, size.cols);

		port->cons.hvc->irq_requested = 1;
		resize_console(port);
		break;
	}
	case VIRTIO_CONSOLE_PORT_OPEN:
		port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
		wake_up_interruptible(&port->waitqueue);
		/*
		 * If the host port got closed and the host had any
		 * unconsumed buffers, we'll be able to reclaim them
		 * now.
		 */
		spin_lock_irq(&port->outvq_lock);
		reclaim_consumed_buffers(port);
		spin_unlock_irq(&port->outvq_lock);

		/*
		 * If the guest is connected, it'll be interested in
		 * knowing the host connection state changed.
		 */
		spin_lock_irq(&port->inbuf_lock);
		send_sigio_to_port(port);
		spin_unlock_irq(&port->inbuf_lock);
		break;
	case VIRTIO_CONSOLE_PORT_NAME:
		/*
		 * If we woke up after hibernation, we can get this
		 * again.  Skip it in that case.
		 */
		if (port->name)
			break;

		/*
		 * Skip the size of the header and the cpkt to get the size
		 * of the name that was sent
		 */
		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;

		port->name = kmalloc(name_size, GFP_KERNEL);
		if (!port->name) {
			dev_err(port->dev,
				"Not enough space to store port name\n");
			break;
		}
		strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
			name_size - 1);
		port->name[name_size - 1] = 0;

		/*
		 * Since we only have one sysfs attribute, 'name',
		 * create it only if we have a name for the port.
		 */
		err = sysfs_create_group(&port->dev->kobj,
					 &port_attribute_group);
		if (err) {
			dev_err(port->dev,
				"Error %d creating sysfs device attributes\n",
				err);
		} else {
			/*
			 * Generate a udev event so that appropriate
			 * symlinks can be created based on udev
			 * rules.
			 */
			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
		}
		break;
	}
}

Project: linux
File: virtio_console.c

static void in_intr(struct virtqueue *vq)
{
	struct port *port;
	unsigned long flags;

	port = find_port_by_vq(vq->vdev->priv, vq);
	if (!port)
		return;

	spin_lock_irqsave(&port->inbuf_lock, flags);
	port->inbuf = get_inbuf(port);

	/*
	 * Normally the port should not accept data when the port is
	 * closed. For generic serial ports, the host won't (shouldn't)
	 * send data till the guest is connected. But this condition
	 * can be reached when a console port is not yet connected (no
	 * tty is spawned) and the other side sends out data over the
	 * vring, or when a remote devices start sending data before
	 * the ports are opened.
	 *
	 * A generic serial port will discard data if not connected,
	 * while console ports and rproc-serial ports accepts data at
	 * any time. rproc-serial is initiated with guest_connected to
	 * false because port_fops_open expects this. Console ports are
	 * hooked up with an HVC console and is initialized with
	 * guest_connected to true.
	 */

	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
		discard_port_data(port);

	/* Send a SIGIO indicating new data in case the process asked for it */
	send_sigio_to_port(port);

	spin_unlock_irqrestore(&port->inbuf_lock, flags);

	wake_up_interruptible(&port->waitqueue);

	if (is_console_port(port) && hvc_poll(port->cons.hvc))
		hvc_kick();
}

Project: linux
File: virtio_console.c

static int __init init(void)
{
	int err;

	pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
	if (IS_ERR(pdrvdata.class)) {
		err = PTR_ERR(pdrvdata.class);
		pr_err("Error %d creating virtio-ports class\n", err);
		return err;
	}

	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
	if (!pdrvdata.debugfs_dir)
		pr_warning("Error creating debugfs dir for virtio-ports\n");
	INIT_LIST_HEAD(&pdrvdata.consoles);
	INIT_LIST_HEAD(&pdrvdata.portdevs);

	err = register_virtio_driver(&virtio_console);
	if (err < 0) {
		pr_err("Error %d registering virtio driver\n", err);
		goto free;
	}
	err = register_virtio_driver(&virtio_rproc_serial);
	if (err < 0) {
		pr_err("Error %d registering virtio rproc serial driver\n",
		       err);
		goto unregister;
	}
	return 0;
unregister:
	unregister_virtio_driver(&virtio_console);
free:
	debugfs_remove_recursive(pdrvdata.debugfs_dir);
	class_destroy(pdrvdata.class);
	return err;
}

Project: linux
File: virtio_console.c

static int init_port_console(struct port *port)
{
	int ret;

	/*
	 * The Host's telling us this port is a console port.  Hook it
	 * up with an hvc console.
	 *
	 * To set up and manage our virtual console, we call
	 * hvc_alloc().
	 *
	 * The first argument of hvc_alloc() is the virtual console
	 * number.  The second argument is the parameter for the
	 * notification mechanism (like irq number).  We currently
	 * leave this as zero, virtqueues have implicit notifications.
	 *
	 * The third argument is a "struct hv_ops" containing the
	 * put_chars() get_chars(), notifier_add() and notifier_del()
	 * pointers.  The final argument is the output buffer size: we
	 * can do any size, so we put PAGE_SIZE here.
	 */
	port->cons.vtermno = pdrvdata.next_vtermno;

	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
	if (IS_ERR(port->cons.hvc)) {
		ret = PTR_ERR(port->cons.hvc);
		dev_err(port->dev,
			"error %d allocating hvc for port\n", ret);
		port->cons.hvc = NULL;
		return ret;
	}
	spin_lock_irq(&pdrvdata_lock);
	pdrvdata.next_vtermno++;
	list_add_tail(&port->cons.list, &pdrvdata.consoles);
	spin_unlock_irq(&pdrvdata_lock);
	port->guest_connected = true;

	/*
	 * Start using the new console output if this is the first
	 * console to come up.
	 */
	if (early_put_chars)
		early_put_chars = NULL;

	/* Notify host of port being opened */
	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);

	return 0;
}

Project: linux
File: virtio_console.c

static int init_vqs(struct ports_device *portdev)
{
	vq_callback_t **io_callbacks;
	char **io_names;
	struct virtqueue **vqs;
	u32 i, j, nr_ports, nr_queues;
	int err;

	nr_ports = portdev->max_nr_ports;
	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;

	vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
	io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
	io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
	portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
				  GFP_KERNEL);
	portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
				   GFP_KERNEL);
	if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
	    !portdev->out_vqs) {
		err = -ENOMEM;
		goto free;
	}

	/*
	 * For backward compat (newer host but older guest), the host
	 * spawns a console port first and also inits the vqs for port
	 * 0 before others.
	 */
	j = 0;
	io_callbacks[j] = in_intr;
	io_callbacks[j + 1] = out_intr;
	io_names[j] = "input";
	io_names[j + 1] = "output";
	j += 2;

	if (use_multiport(portdev)) {
		io_callbacks[j] = control_intr;
		io_callbacks[j + 1] = NULL;
		io_names[j] = "control-i";
		io_names[j + 1] = "control-o";

		for (i = 1; i < nr_ports; i++) {
			j += 2;
			io_callbacks[j] = in_intr;
			io_callbacks[j + 1] = out_intr;
			io_names[j] = "input";
			io_names[j + 1] = "output";
		}
	}
	/* Find the queues. */
	err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
					      io_callbacks,
					      (const char **)io_names, NULL);
	if (err)
		goto free;

	j = 0;
	portdev->in_vqs[0] = vqs[0];
	portdev->out_vqs[0] = vqs[1];
	j += 2;
	if (use_multiport(portdev)) {
		portdev->c_ivq = vqs[j];
		portdev->c_ovq = vqs[j + 1];

		for (i = 1; i < nr_ports; i++) {
			j += 2;
			portdev->in_vqs[i] = vqs[j];
			portdev->out_vqs[i] = vqs[j + 1];
		}
	}
	kfree(io_names);
	kfree(io_callbacks);
	kfree(vqs);

	return 0;

free:
	kfree(portdev->out_vqs);
	kfree(portdev->in_vqs);
	kfree(io_names);
	kfree(io_callbacks);
	kfree(vqs);

	return err;
}

Project: linux
File: virtio_console.c

static bool is_console_port(struct port *port)
{
	if (port->cons.hvc)
		return true;
	return false;
}

Project: linux
File: virtio_console.c

static bool is_rproc_serial(const struct virtio_device *vdev)
{
	return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
}

Project: linux
File: virtio_console.c

static int notifier_add_vio(struct hvc_struct *hp, int data)
{
	struct port *port;

	port = find_port_by_vtermno(hp->vtermno);
	if (!port)
		return -EINVAL;

	hp->irq_requested = 1;
	resize_console(port);

	return 0;
}

Project: linux
File: virtio_console.c

static void notifier_del_vio(struct hvc_struct *hp, int data)
{
	hp->irq_requested = 0;
}

Project: linux
File: virtio_console.c

static void out_intr(struct virtqueue *vq)
{
	struct port *port;

	port = find_port_by_vq(vq->vdev->priv, vq);
	if (!port)
		return;

	wake_up_interruptible(&port->waitqueue);
}

Project: linux
File: virtio_console.c

static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
			struct splice_desc *sd)
{
	struct sg_list *sgl = sd->u.data;
	unsigned int offset, len;

	if (sgl->n == sgl->size)
		return 0;

	/* Try lock this page */
	if (pipe_buf_steal(pipe, buf) == 0) {
		/* Get reference and unlock page for moving */
		get_page(buf->page);
		unlock_page(buf->page);

		len = min(buf->len, sd->len);
		sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
	} else {
		/* Failback to copying a page */
		struct page *page = alloc_page(GFP_KERNEL);
		char *src;

		if (!page)
			return -ENOMEM;

		offset = sd->pos & ~PAGE_MASK;

		len = sd->len;
		if (len + offset > PAGE_SIZE)
			len = PAGE_SIZE - offset;

		src = kmap_atomic(buf->page);
		memcpy(page_address(page) + offset, src + buf->offset, len);
		kunmap_atomic(src);

		sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
	}
	sgl->n++;
	sgl->len += len;

	return len;
}

Project: linux
File: virtio_console.c

static int port_fops_fasync(int fd, struct file *filp, int mode)
{
	struct port *port;

	port = filp->private_data;
	return fasync_helper(fd, filp, mode, &port->async_queue);
}

Project: linux
File: virtio_console.c

static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
{
	struct port *port;
	unsigned int ret;

	port = filp->private_data;
	poll_wait(filp, &port->waitqueue, wait);

	if (!port->guest_connected) {
		/* Port got unplugged */
		return POLLHUP;
	}
	ret = 0;
	if (!will_read_block(port))
		ret |= POLLIN | POLLRDNORM;
	if (!will_write_block(port))
		ret |= POLLOUT;
	if (!port->host_connected)
		ret |= POLLHUP;

	return ret;
}

Project: linux
File: virtio_console.c

static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
			      size_t count, loff_t *offp)
{
	struct port *port;
	ssize_t ret;

	port = filp->private_data;

	/* Port is hot-unplugged. */
	if (!port->guest_connected)
		return -ENODEV;

	if (!port_has_data(port)) {
		/*
		 * If nothing's connected on the host just return 0 in
		 * case of list_empty; this tells the userspace app
		 * that there's no connection
		 */
		if (!port->host_connected)
			return 0;
		if (filp->f_flags & O_NONBLOCK)
			return -EAGAIN;

		ret = wait_event_freezable(port->waitqueue,
					   !will_read_block(port));
		if (ret < 0)
			return ret;
	}
	/* Port got hot-unplugged while we were waiting above. */
	if (!port->guest_connected)
		return -ENODEV;
	/*
	 * We could've received a disconnection message while we were
	 * waiting for more data.
	 *
	 * This check is not clubbed in the if() statement above as we
	 * might receive some data as well as the host could get
	 * disconnected after we got woken up from our wait.  So we
	 * really want to give off whatever data we have and only then
	 * check for host_connected.
	 */
	if (!port_has_data(port) && !port->host_connected)
		return 0;

	return fill_readbuf(port, ubuf, count, true);
}

Project: linux
File: virtio_console.c

static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
				      struct file *filp, loff_t *ppos,
				      size_t len, unsigned int flags)
{
	struct port *port = filp->private_data;
	struct sg_list sgl;
	ssize_t ret;
	struct port_buffer *buf;
	struct splice_desc sd = {
		.total_len = len,
		.flags = flags,
		.pos = *ppos,
		.u.data = &sgl,
	};

	/*
	 * Rproc_serial does not yet support splice. To support splice
	 * pipe_to_sg() must allocate dma-buffers and copy content from
	 * regular pages to dma pages. And alloc_buf and free_buf must
	 * support allocating and freeing such a list of dma-buffers.
	 */
	if (is_rproc_serial(port->out_vq->vdev))
		return -EINVAL;

	/*
	 * pipe->nrbufs == 0 means there are no data to transfer,
	 * so this returns just 0 for no data.
	 */
	pipe_lock(pipe);
	if (!pipe->nrbufs) {
		ret = 0;
		goto error_out;
	}

	ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
	if (ret < 0)
		goto error_out;

	buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
	if (!buf) {
		ret = -ENOMEM;
		goto error_out;
	}

	sgl.n = 0;
	sgl.len = 0;
	sgl.size = pipe->nrbufs;
	sgl.sg = buf->sg;
	sg_init_table(sgl.sg, sgl.size);
	ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
	pipe_unlock(pipe);
	if (likely(ret > 0))
		ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);

	if (unlikely(ret <= 0))
		free_buf(buf, true);
	return ret;

error_out:
	pipe_unlock(pipe);
	return ret;
}

Project: linux
File: virtio_console.c

static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
			       size_t count, loff_t *offp)
{
	struct port *port;
	struct port_buffer *buf;
	ssize_t ret;
	bool nonblock;
	struct scatterlist sg[1];

	/* Userspace could be out to fool us */
	if (!count)
		return 0;

	port = filp->private_data;

	nonblock = filp->f_flags & O_NONBLOCK;

	ret = wait_port_writable(port, nonblock);
	if (ret < 0)
		return ret;

	count = min((size_t)(32 * 1024), count);

	buf = alloc_buf(port->out_vq, count, 0);
	if (!buf)
		return -ENOMEM;

	ret = copy_from_user(buf->buf, ubuf, count);
	if (ret) {
		ret = -EFAULT;
		goto free_buf;
	}

	/*
	 * We now ask send_buf() to not spin for generic ports -- we
	 * can re-use the same code path that non-blocking file
	 * descriptors take for blocking file descriptors since the
	 * wait is already done and we're certain the write will go
	 * through to the host.
	 */
	nonblock = true;
	sg_init_one(sg, buf->buf, count);
	ret = __send_to_port(port, sg, 1, count, buf, nonblock);

	if (nonblock && ret > 0)
		goto out;

free_buf:
	free_buf(buf, true);
out:
	return ret;
}

Project: linux
File: virtio_console.c

static bool port_has_data(struct port *port)
{
	unsigned long flags;
	bool ret;

	ret = false;
	spin_lock_irqsave(&port->inbuf_lock, flags);
	port->inbuf = get_inbuf(port);
	if (port->inbuf)
		ret = true;

	spin_unlock_irqrestore(&port->inbuf_lock, flags);
	return ret;
}

Project: linux
File: virtio_console.c

static void reclaim_consumed_buffers(struct port *port)
{
	struct port_buffer *buf;
	unsigned int len;

	if (!port->portdev) {
		/* Device has been unplugged.  vqs are already gone. */
		return;
	}
	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
		free_buf(buf, false);
		port->outvq_full = false;
	}
}

Project: linux
File: virtio_console.c

static void reclaim_dma_bufs(void)
{
	unsigned long flags;
	struct port_buffer *buf, *tmp;
	LIST_HEAD(tmp_list);

	if (list_empty(&pending_free_dma_bufs))
		return;

	/* Create a copy of the pending_free_dma_bufs while holding the lock */
	spin_lock_irqsave(&dma_bufs_lock, flags);
	list_cut_position(&tmp_list, &pending_free_dma_bufs,
			  pending_free_dma_bufs.prev);
	spin_unlock_irqrestore(&dma_bufs_lock, flags);

	/* Release the dma buffers, without irqs enabled */
	list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
		list_del(&buf->list);
		free_buf(buf, true);
	}
}

Project: linux
File: virtio_console.c

static void remove_controlq_data(struct ports_device *portdev)
{
	struct port_buffer *buf;
	unsigned int len;

	if (!use_multiport(portdev))
		return;

	while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
		free_buf(buf, true);

	while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
		free_buf(buf, true);
}

Project: linux
File: virtio_console.c

static void remove_port(struct kref *kref)
{
	struct port *port;

	port = container_of(kref, struct port, kref);

	kfree(port);
}

Project: linux
File: virtio_console.c

static void remove_port_data(struct port *port)
{
	struct port_buffer *buf;

	spin_lock_irq(&port->inbuf_lock);
	/* Remove unused data this port might have received. */
	discard_port_data(port);
	spin_unlock_irq(&port->inbuf_lock);

	/* Remove buffers we queued up for the Host to send us data in. */
	do {
		spin_lock_irq(&port->inbuf_lock);
		buf = virtqueue_detach_unused_buf(port->in_vq);
		spin_unlock_irq(&port->inbuf_lock);
		if (buf)
			free_buf(buf, true);
	} while (buf);

	spin_lock_irq(&port->outvq_lock);
	reclaim_consumed_buffers(port);
	spin_unlock_irq(&port->outvq_lock);

	/* Free pending buffers from the out-queue. */
	do {
		spin_lock_irq(&port->outvq_lock);
		buf = virtqueue_detach_unused_buf(port->out_vq);
		spin_unlock_irq(&port->outvq_lock);
		if (buf)
			free_buf(buf, true);
	} while (buf);
}

Project: linux
File: virtio_console.c

static void remove_vqs(struct ports_device *portdev)
{
	portdev->vdev->config->del_vqs(portdev->vdev);
	kfree(portdev->in_vqs);
	kfree(portdev->out_vqs);
}

Project: linux
File: virtio_console.c

static void resize_console(struct port *port)
{
	struct virtio_device *vdev;

	/* The port could have been hot-unplugged */
	if (!port || !is_console_port(port))
		return;

	vdev = port->portdev->vdev;

	/* Don't test F_SIZE at all if we're rproc: not a valid feature! */
	if (!is_rproc_serial(vdev) &&
	    virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
		hvc_resize(port->cons.hvc, port->cons.ws);
}

Project: linux
File: virtio_console.c

static ssize_t send_control_msg(struct port *port, unsigned int event,
				unsigned int value)
{
	/* Did the port get unplugged before userspace closed it? */
	if (port->portdev)
		return __send_control_msg(port->portdev, port->id, event, value);
	return 0;
}

Project: linux
File: virtio_console.c

static void set_console_size(struct port *port, u16 rows, u16 cols)
{
	if (!port || !is_console_port(port))
		return;

	port->cons.ws.ws_row = rows;
	port->cons.ws.ws_col = cols;
}

Project: linux
File: virtio_console.c

static ssize_t show_port_name(struct device *dev,
			      struct device_attribute *attr, char *buffer)
{
	struct port *port;

	port = dev_get_drvdata(dev);

	return sprintf(buffer, "%s\n", port->name);
}

Project: linux
File: virtio_console.c

static void unplug_port(struct port *port)
{
	spin_lock_irq(&port->portdev->ports_lock);
	list_del(&port->list);
	spin_unlock_irq(&port->portdev->ports_lock);

	spin_lock_irq(&port->inbuf_lock);
	if (port->guest_connected) {
		/* Let the app know the port is going down. */
		send_sigio_to_port(port);

		/* Do this after sigio is actually sent */
		port->guest_connected = false;
		port->host_connected = false;

		wake_up_interruptible(&port->waitqueue);
	}
	spin_unlock_irq(&port->inbuf_lock);

	if (is_console_port(port)) {
		spin_lock_irq(&pdrvdata_lock);
		list_del(&port->cons.list);
		spin_unlock_irq(&pdrvdata_lock);
		hvc_remove(port->cons.hvc);
	}

	remove_port_data(port);

	/*
	 * We should just assume the device itself has gone off --
	 * else a close on an open port later will try to send out a
	 * control message.
	 */
	port->portdev = NULL;

	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
	device_destroy(pdrvdata.class, port->dev->devt);
	cdev_del(port->cdev);

	debugfs_remove(port->debugfs_file);
	kfree(port->name);

	/*
	 * Locks around here are not necessary - a port can't be
	 * opened after we removed the port struct from ports_list
	 * above.
	 */
	kref_put(&port->kref, remove_port);
}

Project: linux
File: virtio_console.c

static inline bool use_multiport(struct ports_device *portdev)
{
	/*
	 * This condition can be true when put_chars is called from
	 * early_init
	 */
	if (!portdev->vdev)
		return false;
	return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
}

Project: linux
File: virtio_console.c

static int virtcons_probe(struct virtio_device *vdev)
{
	struct ports_device *portdev;
	int err;
	bool multiport;
	bool early = early_put_chars != NULL;

	/* We only need a config space if features are offered */
	if (!vdev->config->get &&
	    (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
	     || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
		dev_err(&vdev->dev, "%s failure: config access disabled\n",
			__func__);
		return -EINVAL;
	}

	/* Ensure to read early_put_chars now */
	barrier();

	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
	if (!portdev) {
		err = -ENOMEM;
		goto fail;
	}

	/* Attach this portdev to this virtio_device, and vice-versa. */
	portdev->vdev = vdev;
	vdev->priv = portdev;

	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
					     &portdev_fops);
	if (portdev->chr_major < 0) {
		dev_err(&vdev->dev,
			"Error %d registering chrdev for device %u\n",
			portdev->chr_major, vdev->index);
		err = portdev->chr_major;
		goto free;
	}

	multiport = false;
	portdev->max_nr_ports = 1;

	/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
	if (!is_rproc_serial(vdev) &&
	    virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
				 struct virtio_console_config, max_nr_ports,
				 &portdev->max_nr_ports) == 0) {
		multiport = true;
	}

	err = init_vqs(portdev);
	if (err < 0) {
		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
		goto free_chrdev;
	}

	spin_lock_init(&portdev->ports_lock);
	INIT_LIST_HEAD(&portdev->ports);

	virtio_device_ready(portdev->vdev);

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

	if (multiport) {
		unsigned int nr_added_bufs;

		spin_lock_init(&portdev->c_ivq_lock);
		spin_lock_init(&portdev->c_ovq_lock);

		nr_added_bufs = fill_queue(portdev->c_ivq,
					   &portdev->c_ivq_lock);
		if (!nr_added_bufs) {
			dev_err(&vdev->dev,
				"Error allocating buffers for control queue\n");
			err = -ENOMEM;
			goto free_vqs;
		}
	} else {
		/*
		 * For backward compatibility: Create a console port
		 * if we're running on older host.
		 */
		add_port(portdev, 0);
	}

	spin_lock_irq(&pdrvdata_lock);
	list_add_tail(&portdev->list, &pdrvdata.portdevs);
	spin_unlock_irq(&pdrvdata_lock);

	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
			   VIRTIO_CONSOLE_DEVICE_READY, 1);

	/*
	 * If there was an early virtio console, assume that there are no
	 * other consoles. We need to wait until the hvc_alloc matches the
	 * hvc_instantiate, otherwise tty_open will complain, resulting in
	 * a "Warning: unable to open an initial console" boot failure.
	 * Without multiport this is done in add_port above. With multiport
	 * this might take some host<->guest communication - thus we have to
	 * wait.
	 */
	if (multiport && early)
		wait_for_completion(&early_console_added);

	return 0;

free_vqs:
	/* The host might want to notify mgmt sw about device add failure */
	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
			   VIRTIO_CONSOLE_DEVICE_READY, 0);
	remove_vqs(portdev);
free_chrdev:
	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
free:
	kfree(portdev);
fail:
	return err;
}

Project: linux
File: virtio_console.c

static void virtcons_remove(struct virtio_device *vdev)
{
	struct ports_device *portdev;
	struct port *port, *port2;

	portdev = vdev->priv;

	spin_lock_irq(&pdrvdata_lock);
	list_del(&portdev->list);
	spin_unlock_irq(&pdrvdata_lock);

	/* Disable interrupts for vqs */
	vdev->config->reset(vdev);
	/* Finish up work that's lined up */
	if (use_multiport(portdev))
		cancel_work_sync(&portdev->control_work);
	else
		cancel_work_sync(&portdev->config_work);

	list_for_each_entry_safe(port, port2, &portdev->ports, list)
		unplug_port(port);

	unregister_chrdev(portdev->chr_major, "virtio-portsdev");

	/*
	 * When yanking out a device, we immediately lose the
	 * (device-side) queues.  So there's no point in keeping the
	 * guest side around till we drop our final reference.  This
	 * also means that any ports which are in an open state will
	 * have to just stop using the port, as the vqs are going
	 * away.
	 */
	remove_controlq_data(portdev);
	remove_vqs(portdev);
	kfree(portdev);
}

Project: linux
File: virtio_console.c

static int virtcons_restore(struct virtio_device *vdev)
{
	struct ports_device *portdev;
	struct port *port;
	int ret;

	portdev = vdev->priv;

	ret = init_vqs(portdev);
	if (ret)
		return ret;

	virtio_device_ready(portdev->vdev);

	if (use_multiport(portdev))
		fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);

	list_for_each_entry(port, &portdev->ports, list) {
		port->in_vq = portdev->in_vqs[port->id];
		port->out_vq = portdev->out_vqs[port->id];

		fill_queue(port->in_vq, &port->inbuf_lock);

		/* Get port open/close status on the host */
		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);

		/*
		 * If a port was open at the time of suspending, we
		 * have to let the host know that it's still open.
		 */
		if (port->guest_connected)
			send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
	}
	return 0;
}

Project: linux
File: virtio_console.c

static int wait_port_writable(struct port *port, bool nonblock)
{
	int ret;

	if (will_write_block(port)) {
		if (nonblock)
			return -EAGAIN;

		ret = wait_event_freezable(port->waitqueue,
					   !will_write_block(port));
		if (ret < 0)
			return ret;
	}
	/* Port got hot-unplugged. */
	if (!port->guest_connected)
		return -ENODEV;

	return 0;
}

Project: linux
File: virtio_console.c

static bool will_write_block(struct port *port)
{
	bool ret;

	if (!port->guest_connected) {
		/* Port got hot-unplugged. Let's exit. */
		return false;
	}
	if (!port->host_connected)
		return true;

	spin_lock_irq(&port->outvq_lock);
	/*
	 * Check if the Host has consumed any buffers since we last
	 * sent data (this is only applicable for nonblocking ports).
	 */
	reclaim_consumed_buffers(port);
	ret = port->outvq_full;
	spin_unlock_irq(&port->outvq_lock);

	return ret;
}