static int backend_connect()

in pvcalls-back.c [921:986]

• 55 lines of code
• 9 McCabe index (conditional complexity)

static int backend_connect(struct xenbus_device *dev)
{
	int err;
	evtchn_port_t evtchn;
	grant_ref_t ring_ref;
	struct pvcalls_fedata *fedata = NULL;

	fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
	if (!fedata)
		return -ENOMEM;

	fedata->irq = -1;
	err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
			   &evtchn);
	if (err != 1) {
		err = -EINVAL;
		xenbus_dev_fatal(dev, err, "reading %s/event-channel",
				 dev->otherend);
		goto error;
	}

	err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
	if (err != 1) {
		err = -EINVAL;
		xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
				 dev->otherend);
		goto error;
	}

	err = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
	if (err < 0)
		goto error;
	fedata->irq = err;

	err = request_threaded_irq(fedata->irq, NULL, pvcalls_back_event,
				   IRQF_ONESHOT, "pvcalls-back", dev);
	if (err < 0)
		goto error;

	err = xenbus_map_ring_valloc(dev, &ring_ref, 1,
				     (void **)&fedata->sring);
	if (err < 0)
		goto error;

	BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
	fedata->dev = dev;

	INIT_LIST_HEAD(&fedata->socket_mappings);
	INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
	sema_init(&fedata->socket_lock, 1);
	dev_set_drvdata(&dev->dev, fedata);

	down(&pvcalls_back_global.frontends_lock);
	list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
	up(&pvcalls_back_global.frontends_lock);

	return 0;

 error:
	if (fedata->irq >= 0)
		unbind_from_irqhandler(fedata->irq, dev);
	if (fedata->sring != NULL)
		xenbus_unmap_ring_vfree(dev, fedata->sring);
	kfree(fedata);
	return err;
}