static int balloon_connect_vsp()

in hv_balloon.c [1656:1762]

• 62 lines of code
• 8 McCabe index (conditional complexity)

static int balloon_connect_vsp(struct hv_device *dev)
{
	struct dm_version_request version_req;
	struct dm_capabilities cap_msg;
	unsigned long t;
	int ret;

	ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
			 balloon_onchannelcallback, dev);
	if (ret)
		return ret;

	/*
	 * Initiate the hand shake with the host and negotiate
	 * a version that the host can support. We start with the
	 * highest version number and go down if the host cannot
	 * support it.
	 */
	memset(&version_req, 0, sizeof(struct dm_version_request));
	version_req.hdr.type = DM_VERSION_REQUEST;
	version_req.hdr.size = sizeof(struct dm_version_request);
	version_req.hdr.trans_id = atomic_inc_return(&trans_id);
	version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;
	version_req.is_last_attempt = 0;
	dm_device.version = version_req.version.version;

	ret = vmbus_sendpacket(dev->channel, &version_req,
			       sizeof(struct dm_version_request),
			       (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);
	if (ret)
		goto out;

	t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
	if (t == 0) {
		ret = -ETIMEDOUT;
		goto out;
	}

	/*
	 * If we could not negotiate a compatible version with the host
	 * fail the probe function.
	 */
	if (dm_device.state == DM_INIT_ERROR) {
		ret = -EPROTO;
		goto out;
	}

	pr_info("Using Dynamic Memory protocol version %u.%u\n",
		DYNMEM_MAJOR_VERSION(dm_device.version),
		DYNMEM_MINOR_VERSION(dm_device.version));

	/*
	 * Now submit our capabilities to the host.
	 */
	memset(&cap_msg, 0, sizeof(struct dm_capabilities));
	cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
	cap_msg.hdr.size = sizeof(struct dm_capabilities);
	cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);

	/*
	 * When hibernation (i.e. virtual ACPI S4 state) is enabled, the host
	 * currently still requires the bits to be set, so we have to add code
	 * to fail the host's hot-add and balloon up/down requests, if any.
	 */
	cap_msg.caps.cap_bits.balloon = 1;
	cap_msg.caps.cap_bits.hot_add = 1;

	/*
	 * Specify our alignment requirements as it relates
	 * memory hot-add. Specify 128MB alignment.
	 */
	cap_msg.caps.cap_bits.hot_add_alignment = 7;

	/*
	 * Currently the host does not use these
	 * values and we set them to what is done in the
	 * Windows driver.
	 */
	cap_msg.min_page_cnt = 0;
	cap_msg.max_page_number = -1;

	ret = vmbus_sendpacket(dev->channel, &cap_msg,
			       sizeof(struct dm_capabilities),
			       (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);
	if (ret)
		goto out;

	t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
	if (t == 0) {
		ret = -ETIMEDOUT;
		goto out;
	}

	/*
	 * If the host does not like our capabilities,
	 * fail the probe function.
	 */
	if (dm_device.state == DM_INIT_ERROR) {
		ret = -EPROTO;
		goto out;
	}

	return 0;
out:
	vmbus_close(dev->channel);
	return ret;
}