Re: [PATCH 5/5] input: twl6040-vibra: remove mutex
From: H. Nikolaus Schaller
Date: Tue Apr 19 2016 - 03:49:12 EST
> Am 18.04.2016 um 23:20 schrieb Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>:
>
> On Mon, Apr 18, 2016 at 09:55:41PM +0200, H. Nikolaus Schaller wrote:
>> The mutex does not seem to be needed.
>
> twl6040_vibra_suspend() and vibra_play_work() may run concurrently, no?
Hm. I don't know about the rule that would give an answer to this question...
I will test a little to see if the mutex has unexpected side-effects.
>
>> twl4030-vibra doesn't
>> use one either.
>
> It probably should.
>
> Thanks.
>
>>
>> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
>> ---
>> drivers/input/misc/twl6040-vibra.c | 15 +--------------
>> 1 file changed, 1 insertion(+), 14 deletions(-)
>>
>> diff --git a/drivers/input/misc/twl6040-vibra.c b/drivers/input/misc/twl6040-vibra.c
>> index 69c5940..dcc926b 100644
>> --- a/drivers/input/misc/twl6040-vibra.c
>> +++ b/drivers/input/misc/twl6040-vibra.c
>> @@ -46,7 +46,7 @@ struct vibra_info {
>> struct device *dev;
>> struct input_dev *input_dev;
>> struct work_struct play_work;
>> - struct mutex mutex;
>> +
>> int irq;
>>
>> bool enabled;
>> @@ -182,8 +182,6 @@ static void vibra_play_work(struct work_struct *work)
>> struct vibra_info *info = container_of(work,
>> struct vibra_info, play_work);
>>
>> - mutex_lock(&info->mutex);
>> -
>> if (info->weak_speed || info->strong_speed) {
>> if (!info->enabled)
>> twl6040_vibra_enable(info);
>> @@ -192,7 +190,6 @@ static void vibra_play_work(struct work_struct *work)
>> } else if (info->enabled)
>> twl6040_vibra_disable(info);
>>
>> - mutex_unlock(&info->mutex);
>> }
>>
>> static int vibra_play(struct input_dev *input, void *data,
>> @@ -223,12 +220,8 @@ static void twl6040_vibra_close(struct input_dev *input)
>>
>> cancel_work_sync(&info->play_work);
>>
>> - mutex_lock(&info->mutex);
>> -
>> if (info->enabled)
>> twl6040_vibra_disable(info);
>> -
>> - mutex_unlock(&info->mutex);
>> }
>>
>> static int __maybe_unused twl6040_vibra_suspend(struct device *dev)
>> @@ -236,13 +229,9 @@ static int __maybe_unused twl6040_vibra_suspend(struct device *dev)
>> struct platform_device *pdev = to_platform_device(dev);
>> struct vibra_info *info = platform_get_drvdata(pdev);
>>
>> - mutex_lock(&info->mutex);
>> -
>> if (info->enabled)
>> twl6040_vibra_disable(info);
>>
>> - mutex_unlock(&info->mutex);
>> -
>> return 0;
>> }
>>
>> @@ -301,8 +290,6 @@ static int twl6040_vibra_probe(struct platform_device *pdev)
>> return -EINVAL;
>> }
>>
>> - mutex_init(&info->mutex);
>> -
>> error = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
>> twl6040_vib_irq_handler,
>> IRQF_ONESHOT,
>> --
>> 2.7.3
>>
>
> --
> Dmitry