linux-kernel - Re: [PATCH v4 18/25] x86: Use do_kernel_power

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Message-ID: <3082ba7a-f8f6-b2d9-5ae3-ec639b1a6bee@gmail.com>
Date:   Mon, 29 Nov 2021 00:06:57 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Thierry Reding <thierry.reding@...il.com>,
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Subject: Re: [PATCH v4 18/25] x86: Use do_kernel_power_off()

28.11.2021 04:15, Michał Mirosław пишет:
> On Fri, Nov 26, 2021 at 09:00:54PM +0300, Dmitry Osipenko wrote:
>> Kernel now supports chained power-off handlers. Use do_kernel_power_off()
>> that invokes chained power-off handlers. It also invokes legacy
>> pm_power_off() for now, which will be removed once all drivers will
>> be converted to the new power-off API.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
>> ---
>>  arch/x86/kernel/reboot.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
>> index 0a40df66a40d..cd7d9416d81a 100644
>> --- a/arch/x86/kernel/reboot.c
>> +++ b/arch/x86/kernel/reboot.c
>> @@ -747,10 +747,10 @@ static void native_machine_halt(void)
>>  
>>  static void native_machine_power_off(void)
>>  {
>> -	if (pm_power_off) {
>> +	if (kernel_can_power_off()) {
>>  		if (!reboot_force)
>>  			machine_shutdown();
>> -		pm_power_off();
>> +		do_kernel_power_off();
>>  	}
> 
> Judging from an old commit from 2006 [1], this can be rewritten as:
> 
> if (!reboot_force && kernel_can_power_off())
> 	machine_shutdown();
> do_kernel_power_off();
> 
> And maybe later reworked so it doesn't need kernel_can_power_off().
> 
> [1] http://lkml.iu.edu/hypermail//linux/kernel/0511.3/0681.html

It could be rewritten like you're suggesting, but I'd prefer to keep the
old variant, for clarity.