Re: [PATCH v7 04/20] kernel: Add combined power-off+restart handler call chain API

Dmitry Osipenko
2022-05-06T15:29:04Z

On 4/20/22 21:47, Rafael J. Wysocki wrote:
>>>> + spin_unlock(&platform_power_off_lock);
>>>> +
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + ret = register_power_off_handler(&priv->power_off_nb);
>>>> + if (ret)
>>>> + priv->platform_power_off_cb = NULL;
>>>> +
>>>> + return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(register_platform_power_off);
>>>> +
>>>> +/**
>>>> + * unregister_platform_power_off - Unregister platform-level power-off callback
>>>> + * @power_off: Power-off callback
>>>> + *
>>>> + * Unregisters previously registered platform power-off callback.
>>>> + *
>>>> + * Returns zero on success, or error code on failure.
>>>> + */
>>>> +int unregister_platform_power_off(void (*power_off)(void))
>>>> +{
>>>> + struct sys_off_handler_private_data *priv;
>>>> + int ret;
>>>> +
>>>> + priv = sys_off_handler_private_data(&platform_power_off_handler);
>>>> +
>>>> + if (priv->platform_power_off_cb != power_off)
>>>> + return -EINVAL;
>>>> +
>>>> + ret = unregister_power_off_handler(&priv->power_off_nb);
>>>> + priv->platform_power_off_cb = NULL;
>>>> +
>>>> + return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(unregister_platform_power_off);
>>>> +
>>>> +/**
>>>> + * do_kernel_power_off - Execute kernel power-off handler call chain
>>>> + *
>>>> + * Calls functions registered with register_power_off_handler.
>>>> + *
>>>> + * Expected to be called as last step of the power-off sequence.
>>>> + *
>>>> + * Powers off the system immediately if a power-off handler function has
>>>> + * been registered. Otherwise does nothing.
>>>> + */
>>>> +void do_kernel_power_off(void)
>>>> +{
>>>> + /* legacy pm_power_off() is unchained and has highest priority */
>>>> + if (pm_power_off && pm_power_off != dummy_pm_power_off)
>>>> + return pm_power_off();
>>>> +
>>>> + blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL,
>>>> + NULL);
>>>> +}
>>>> +
>>>> +static void do_kernel_power_off_prepare(void)
>>>> +{
>>>> + /* legacy pm_power_off_prepare() is unchained and has highest priority */
>>>> + if (pm_power_off_prepare)
>>>> + return pm_power_off_prepare();
>>>> +
>>>> + blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
>>>> + NULL);
>>>> +}
>>>> +
>>>> /**
>>>> * kernel_power_off - power_off the system
>>>> *
>>>> @@ -304,8 +893,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
>>>> void kernel_power_off(void)
>>>> {
>>>> kernel_shutdown_prepare(SYSTEM_POWER_OFF);
>>>> - if (pm_power_off_prepare)
>>>> - pm_power_off_prepare();
>>>> + do_kernel_power_off_prepare();
>>>> migrate_to_reboot_cpu();
>>>> syscore_shutdown();
>>>> pr_emerg("Power down\n");
>>>> @@ -314,6 +902,16 @@ void kernel_power_off(void)
>>>> }
>>>> EXPORT_SYMBOL_GPL(kernel_power_off);
>>>>
>>>> +bool kernel_can_power_off(void)
>>>> +{
>>>> + if (!pm_power_off &&
>>>> + blocking_notifier_call_chain_is_empty(&power_off_handler_list))
>>>> + return false;
>>>> +
>>>> + return true;
>>> return pm_power_off ||
>>> blocking_notifier_call_chain_is_empty(&power_off_handler_list);
>> Thank you for the thorough review!
> You're very welcome!

Thanks again for taking a look at the patches. I don't have strong
preferences about the names and etc, so I'll update it all in v8 like
you suggested.

--
Best regards,
Dmitry