static int __init state_next()

in amd/init.c [2886:2954]

• 63 lines of code
• 18 McCabe index (conditional complexity)

static int __init state_next(void)
{
	int ret = 0;

	switch (init_state) {
	case IOMMU_START_STATE:
		if (!detect_ivrs()) {
			init_state	= IOMMU_NOT_FOUND;
			ret		= -ENODEV;
		} else {
			init_state	= IOMMU_IVRS_DETECTED;
		}
		break;
	case IOMMU_IVRS_DETECTED:
		if (amd_iommu_disabled) {
			init_state = IOMMU_CMDLINE_DISABLED;
			ret = -EINVAL;
		} else {
			ret = early_amd_iommu_init();
			init_state = ret ? IOMMU_INIT_ERROR : IOMMU_ACPI_FINISHED;
		}
		break;
	case IOMMU_ACPI_FINISHED:
		early_enable_iommus();
		x86_platform.iommu_shutdown = disable_iommus;
		init_state = IOMMU_ENABLED;
		break;
	case IOMMU_ENABLED:
		register_syscore_ops(&amd_iommu_syscore_ops);
		ret = amd_iommu_init_pci();
		init_state = ret ? IOMMU_INIT_ERROR : IOMMU_PCI_INIT;
		enable_iommus_v2();
		break;
	case IOMMU_PCI_INIT:
		ret = amd_iommu_enable_interrupts();
		init_state = ret ? IOMMU_INIT_ERROR : IOMMU_INTERRUPTS_EN;
		break;
	case IOMMU_INTERRUPTS_EN:
		init_state = IOMMU_INITIALIZED;
		break;
	case IOMMU_INITIALIZED:
		/* Nothing to do */
		break;
	case IOMMU_NOT_FOUND:
	case IOMMU_INIT_ERROR:
	case IOMMU_CMDLINE_DISABLED:
		/* Error states => do nothing */
		ret = -EINVAL;
		break;
	default:
		/* Unknown state */
		BUG();
	}

	if (ret) {
		free_dma_resources();
		if (!irq_remapping_enabled) {
			disable_iommus();
			free_iommu_resources();
		} else {
			struct amd_iommu *iommu;

			uninit_device_table_dma();
			for_each_iommu(iommu)
				iommu_flush_all_caches(iommu);
		}
	}
	return ret;
}