static int xen_pcibk_setup_backend()

in xen-pciback/xenbus.c [562:657]

• 80 lines of code
• 14 McCabe index (conditional complexity)

static int xen_pcibk_setup_backend(struct xen_pcibk_device *pdev)
{
	/* Get configuration from xend (if available now) */
	int domain, bus, slot, func;
	int err = 0;
	int i, num_devs;
	char dev_str[64];
	char state_str[64];

	mutex_lock(&pdev->dev_lock);
	/* It's possible we could get the call to setup twice, so make sure
	 * we're not already connected.
	 */
	if (xenbus_read_driver_state(pdev->xdev->nodename) !=
	    XenbusStateInitWait)
		goto out;

	dev_dbg(&pdev->xdev->dev, "getting be setup\n");

	err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, "num_devs", "%d",
			   &num_devs);
	if (err != 1) {
		if (err >= 0)
			err = -EINVAL;
		xenbus_dev_fatal(pdev->xdev, err,
				 "Error reading number of devices");
		goto out;
	}

	for (i = 0; i < num_devs; i++) {
		int l = snprintf(dev_str, sizeof(dev_str), "dev-%d", i);
		if (unlikely(l >= (sizeof(dev_str) - 1))) {
			err = -ENOMEM;
			xenbus_dev_fatal(pdev->xdev, err,
					 "String overflow while reading "
					 "configuration");
			goto out;
		}

		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, dev_str,
				   "%x:%x:%x.%x", &domain, &bus, &slot, &func);
		if (err < 0) {
			xenbus_dev_fatal(pdev->xdev, err,
					 "Error reading device configuration");
			goto out;
		}
		if (err != 4) {
			err = -EINVAL;
			xenbus_dev_fatal(pdev->xdev, err,
					 "Error parsing pci device "
					 "configuration");
			goto out;
		}

		err = xen_pcibk_export_device(pdev, domain, bus, slot, func, i);
		if (err)
			goto out;

		/* Switch substate of this device. */
		l = snprintf(state_str, sizeof(state_str), "state-%d", i);
		if (unlikely(l >= (sizeof(state_str) - 1))) {
			err = -ENOMEM;
			xenbus_dev_fatal(pdev->xdev, err,
					 "String overflow while reading "
					 "configuration");
			goto out;
		}
		err = xenbus_printf(XBT_NIL, pdev->xdev->nodename, state_str,
				    "%d", XenbusStateInitialised);
		if (err) {
			xenbus_dev_fatal(pdev->xdev, err, "Error switching "
					 "substate of dev-%d\n", i);
			goto out;
		}
	}

	err = xen_pcibk_publish_pci_roots(pdev, xen_pcibk_publish_pci_root);
	if (err) {
		xenbus_dev_fatal(pdev->xdev, err,
				 "Error while publish PCI root buses "
				 "for frontend");
		goto out;
	}

	err = xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
	if (err)
		xenbus_dev_fatal(pdev->xdev, err,
				 "Error switching to initialised state!");

out:
	mutex_unlock(&pdev->dev_lock);
	if (!err)
		/* see if pcifront is already configured (if not, we'll wait) */
		xen_pcibk_attach(pdev);
	return err;
}