[RFC PATCH] bq27000 battery mutex protection

[Michael Trimarchi]

Lars-Peter Clausen wrote:
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> Michael Trimarchi wrote:
>
>   
>> Protect the data using a mutex. Fix a race that can happen when
>> the user read from the sysfs and the worker execute in the middle.
>>
>> Signed-off-by: Michael Trimarchi <michael at panicking.kicks-ass.org>
>>
>> diff --git a/drivers/power/bq27000_battery.c
>>     
> b/drivers/power/bq27000_battery.c
>   
>> index 01168ea..ddee537 100644
>> --- a/drivers/power/bq27000_battery.c
>> +++ b/drivers/power/bq27000_battery.c
>> @@ -134,6 +134,7 @@ struct bq27000_device_info {
>>     struct bq27000_bat_regs regs;
>> };
>>
>> +static DEFINE_MUTEX(battery_mutex);
>> static unsigned int cache_time = 5000;
>> module_param(cache_time, uint, 0644);
>> MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
>>
>> ...
>>
>> static void bq27000_battery_work(struct work_struct *work)
>> @@ -353,6 +383,8 @@ static void bq27000_battery_work(struct work_struct
>>     
> *work)
>   
>>     struct bq27000_device_info *di =
>>         container_of(work, struct bq27000_device_info, work.work);
>>
>> +    mutex_lock(&battery_mutex);
>> +
>>     if ((di->pdata->hdq_initialized)()) {
>>         struct bq27000_bat_regs regs;
>>
>> @@ -375,6 +407,8 @@ static void bq27000_battery_work(struct work_struct
>>     
> *work)
>   
>>     if (!schedule_delayed_work(&di->work, cache_time))
>>         dev_err(di->dev, "battery service reschedule failed\n");
>> +
>> +    mutex_unlock(&battery_mutex);
>> }
>>     
Ok, I will change it
Michael
>  
> You only need to protect the assignment to di->regs. There is no need
> to hold the look for the whole function call.
>
> - -Lars
>  static enum power_supply_property bq27000_battery_props[] = {
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