linux-kernel - Re: [PATCH v4 1/2] power_supply: Register cooling device outside of probe

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Message-ID: <35141cc2-8269-b4c6-8763-6f18c96ea12c@quicinc.com>
Date:   Fri, 27 May 2022 19:28:46 +0530
From:   Manaf Meethalavalappu Pallikunhi <quic_manafm@...cinc.com>
To:     Sebastian Reichel <sre@...nel.org>
CC:     David Collins <quic_collinsd@...cinc.com>,
        Subbaraman Narayanamurthy <quic_subbaram@...cinc.com>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <gregkh@...gle.com>
Subject: Re: [PATCH v4 1/2] power_supply: Register cooling device outside of
 probe

++

On 1/25/2022 1:04 AM, Manaf Meethalavalappu Pallikunhi wrote:
> Hi Sebastian Reichel,
>
> Just reminder for review for these patches
>
> Thanks,
>
> Manaf
>
> On 12/22/2021 2:11 PM, Manaf Meethalavalappu Pallikunhi wrote:
>> Registering the cooling device from the probe can result in the
>> execution of get_property() function before it gets initialized.
>>
>> To avoid this, register the cooling device from a workqueue
>> instead of registering in the probe.
>>
>> Signed-off-by: Manaf Meethalavalappu Pallikunhi 
>> <quic_manafm@...cinc.com>
>> ---
>>   drivers/power/supply/power_supply_core.c | 10 ++++------
>>   1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/power/supply/power_supply_core.c 
>> b/drivers/power/supply/power_supply_core.c
>> index 668369b..ef6f290 100644
>> --- a/drivers/power/supply/power_supply_core.c
>> +++ b/drivers/power/supply/power_supply_core.c
>> @@ -132,6 +132,7 @@ void power_supply_changed(struct power_supply *psy)
>>   }
>>   EXPORT_SYMBOL_GPL(power_supply_changed);
>>   +static int psy_register_cooler(struct power_supply *psy);
>>   /*
>>    * Notify that power supply was registered after parent finished 
>> the probing.
>>    *
>> @@ -139,6 +140,8 @@ EXPORT_SYMBOL_GPL(power_supply_changed);
>>    * calling power_supply_changed() directly from 
>> power_supply_register()
>>    * would lead to execution of get_property() function provided by 
>> the driver
>>    * too early - before the probe ends.
>> + * Also, registering cooling device from the probe will execute the
>> + * get_property() function. So register the cooling device after the 
>> probe.
>>    *
>>    * Avoid that by waiting on parent's mutex.
>>    */
>> @@ -156,6 +159,7 @@ static void 
>> power_supply_deferred_register_work(struct work_struct *work)
>>       }
>>         power_supply_changed(psy);
>> +    psy_register_cooler(psy);
>>         if (psy->dev.parent)
>>           mutex_unlock(&psy->dev.parent->mutex);
>> @@ -1238,10 +1242,6 @@ __power_supply_register(struct device *parent,
>>       if (rc)
>>           goto register_thermal_failed;
>>   -    rc = psy_register_cooler(psy);
>> -    if (rc)
>> -        goto register_cooler_failed;
>> -
>>       rc = power_supply_create_triggers(psy);
>>       if (rc)
>>           goto create_triggers_failed;
>> @@ -1271,8 +1271,6 @@ __power_supply_register(struct device *parent,
>>   add_hwmon_sysfs_failed:
>>       power_supply_remove_triggers(psy);
>>   create_triggers_failed:
>> -    psy_unregister_cooler(psy);
>> -register_cooler_failed:
>>       psy_unregister_thermal(psy);
>>   register_thermal_failed:
>>       device_del(dev);
>>