static int __device_suspend()

in power/main.c [1606:1726]

• 87 lines of code
• 23 McCabe index (conditional complexity)

static int __device_suspend(struct device *dev, pm_message_t state, bool async)
{
	pm_callback_t callback = NULL;
	const char *info = NULL;
	int error = 0;
	DECLARE_DPM_WATCHDOG_ON_STACK(wd);

	TRACE_DEVICE(dev);
	TRACE_SUSPEND(0);

	dpm_wait_for_subordinate(dev, async);

	if (async_error) {
		dev->power.direct_complete = false;
		goto Complete;
	}

	/*
	 * Wait for possible runtime PM transitions of the device in progress
	 * to complete and if there's a runtime resume request pending for it,
	 * resume it before proceeding with invoking the system-wide suspend
	 * callbacks for it.
	 *
	 * If the system-wide suspend callbacks below change the configuration
	 * of the device, they must disable runtime PM for it or otherwise
	 * ensure that its runtime-resume callbacks will not be confused by that
	 * change in case they are invoked going forward.
	 */
	pm_runtime_barrier(dev);

	if (pm_wakeup_pending()) {
		dev->power.direct_complete = false;
		async_error = -EBUSY;
		goto Complete;
	}

	if (dev->power.syscore)
		goto Complete;

	/* Avoid direct_complete to let wakeup_path propagate. */
	if (device_may_wakeup(dev) || device_wakeup_path(dev))
		dev->power.direct_complete = false;

	if (dev->power.direct_complete) {
		if (pm_runtime_status_suspended(dev)) {
			pm_runtime_disable(dev);
			if (pm_runtime_status_suspended(dev)) {
				pm_dev_dbg(dev, state, "direct-complete ");
				goto Complete;
			}

			pm_runtime_enable(dev);
		}
		dev->power.direct_complete = false;
	}

	dev->power.may_skip_resume = true;
	dev->power.must_resume = !dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME);

	dpm_watchdog_set(&wd, dev);
	device_lock(dev);

	if (dev->pm_domain) {
		info = "power domain ";
		callback = pm_op(&dev->pm_domain->ops, state);
		goto Run;
	}

	if (dev->type && dev->type->pm) {
		info = "type ";
		callback = pm_op(dev->type->pm, state);
		goto Run;
	}

	if (dev->class && dev->class->pm) {
		info = "class ";
		callback = pm_op(dev->class->pm, state);
		goto Run;
	}

	if (dev->bus) {
		if (dev->bus->pm) {
			info = "bus ";
			callback = pm_op(dev->bus->pm, state);
		} else if (dev->bus->suspend) {
			pm_dev_dbg(dev, state, "legacy bus ");
			error = legacy_suspend(dev, state, dev->bus->suspend,
						"legacy bus ");
			goto End;
		}
	}

 Run:
	if (!callback && dev->driver && dev->driver->pm) {
		info = "driver ";
		callback = pm_op(dev->driver->pm, state);
	}

	error = dpm_run_callback(callback, dev, state, info);

 End:
	if (!error) {
		dev->power.is_suspended = true;
		if (device_may_wakeup(dev))
			dev->power.wakeup_path = true;

		dpm_propagate_wakeup_to_parent(dev);
		dpm_clear_superiors_direct_complete(dev);
	}

	device_unlock(dev);
	dpm_watchdog_clear(&wd);

 Complete:
	if (error)
		async_error = error;

	complete_all(&dev->power.completion);
	TRACE_SUSPEND(error);
	return error;
}