[media] soc-camera: protect against racing open(2) and rmmod

static int soc_camera_open(struct file *file)

{

	struct video_device *vdev = video_devdata(file);

	struct soc_camera_device *icd = dev_get_drvdata(vdev->parent);

	struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);

	struct soc_camera_device *icd;

	struct soc_camera_host *ici;

	int ret;

	if (!to_soc_camera_control(icd))

		/* No device driver attached */

		return -ENODEV;

	/*

	 * Don't mess with the host during probe: wait until the loop in

	 * scan_add_host() completes

	 * scan_add_host() completes. Also protect against a race with

	 * soc_camera_host_unregister().

	 */

	if (mutex_lock_interruptible(&list_lock))

		return -ERESTARTSYS;

	if (!vdev || !video_is_registered(vdev)) {

		mutex_unlock(&list_lock);

		return -ENODEV;

	}

	icd = dev_get_drvdata(vdev->parent);

	ici = to_soc_camera_host(icd->parent);

	ret = try_module_get(ici->ops->owner) ? 0 : -ENODEV;

	mutex_unlock(&list_lock);

	if (mutex_lock_interruptible(&ici->host_lock))

		return -ERESTARTSYS;

	if (!try_module_get(ici->ops->owner)) {

	if (ret < 0) {

		dev_err(icd->pdev, "Couldn't lock capture bus driver.\n");

		ret = -EINVAL;

		goto emodule;

		return ret;

	}

	if (!to_soc_camera_control(icd)) {

		/* No device driver attached */

		ret = -ENODEV;

		goto econtrol;

	}

	if (mutex_lock_interruptible(&ici->host_lock)) {

		ret = -ERESTARTSYS;

		goto elockhost;

	}

	icd->use_count++;

	/* Now we really have to activate the camera */

	if (icd->use_count == 1) {

		struct soc_camera_desc *sdesc = to_soc_camera_desc(icd);

		/* Restore parameters before the last close() per V4L2 API */

		struct v4l2_format f = {

			.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,

	ici->ops->remove(icd);

eiciadd:

	icd->use_count--;

	module_put(ici->ops->owner);

emodule:

	mutex_unlock(&ici->host_lock);

elockhost:

econtrol:

	module_put(ici->ops->owner);

	return ret;

}