static void balloon_onchannelcallback()

in hv_balloon.c [1475:1571]
75 lines of code
13 McCabe index (conditional complexity)

static void balloon_onchannelcallback(void *context)
{
	struct hv_device *dev = context;
	u32 recvlen;
	u64 requestid;
	struct dm_message *dm_msg;
	struct dm_header *dm_hdr;
	struct hv_dynmem_device *dm = hv_get_drvdata(dev);
	struct dm_balloon *bal_msg;
	struct dm_hot_add *ha_msg;
	union dm_mem_page_range *ha_pg_range;
	union dm_mem_page_range *ha_region;

	memset(recv_buffer, 0, sizeof(recv_buffer));
	vmbus_recvpacket(dev->channel, recv_buffer,
			 HV_HYP_PAGE_SIZE, &recvlen, &requestid);

	if (recvlen > 0) {
		dm_msg = (struct dm_message *)recv_buffer;
		dm_hdr = &dm_msg->hdr;

		switch (dm_hdr->type) {
		case DM_VERSION_RESPONSE:
			version_resp(dm,
				 (struct dm_version_response *)dm_msg);
			break;

		case DM_CAPABILITIES_RESPONSE:
			cap_resp(dm,
				 (struct dm_capabilities_resp_msg *)dm_msg);
			break;

		case DM_BALLOON_REQUEST:
			if (allow_hibernation) {
				pr_info("Ignore balloon-up request!\n");
				break;
			}

			if (dm->state == DM_BALLOON_UP)
				pr_warn("Currently ballooning\n");
			bal_msg = (struct dm_balloon *)recv_buffer;
			dm->state = DM_BALLOON_UP;
			dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
			schedule_work(&dm_device.balloon_wrk.wrk);
			break;

		case DM_UNBALLOON_REQUEST:
			if (allow_hibernation) {
				pr_info("Ignore balloon-down request!\n");
				break;
			}

			dm->state = DM_BALLOON_DOWN;
			balloon_down(dm,
				 (struct dm_unballoon_request *)recv_buffer);
			break;

		case DM_MEM_HOT_ADD_REQUEST:
			if (dm->state == DM_HOT_ADD)
				pr_warn("Currently hot-adding\n");
			dm->state = DM_HOT_ADD;
			ha_msg = (struct dm_hot_add *)recv_buffer;
			if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
				/*
				 * This is a normal hot-add request specifying
				 * hot-add memory.
				 */
				dm->host_specified_ha_region = false;
				ha_pg_range = &ha_msg->range;
				dm->ha_wrk.ha_page_range = *ha_pg_range;
				dm->ha_wrk.ha_region_range.page_range = 0;
			} else {
				/*
				 * Host is specifying that we first hot-add
				 * a region and then partially populate this
				 * region.
				 */
				dm->host_specified_ha_region = true;
				ha_pg_range = &ha_msg->range;
				ha_region = &ha_pg_range[1];
				dm->ha_wrk.ha_page_range = *ha_pg_range;
				dm->ha_wrk.ha_region_range = *ha_region;
			}
			schedule_work(&dm_device.ha_wrk.wrk);
			break;

		case DM_INFO_MESSAGE:
			process_info(dm, (struct dm_info_msg *)dm_msg);
			break;

		default:
			pr_warn("Unhandled message: type: %d\n", dm_hdr->type);

		}
	}

}