Re: [PATCH] iio: remove unnecessary condition judgment in am2315_trigger_handler

From: zhong jiang
Date: Mon Sep 10 2018 - 21:16:51 EST


On 2018/9/10 21:49, zhong jiang wrote:
> On 2018/9/8 22:17, Jonathan Cameron wrote:
>> On Sat, 8 Sep 2018 17:59:13 +0530
>> Himanshu Jha <himanshujha199640@xxxxxxxxx> wrote:
>>
>>> On Sat, Sep 08, 2018 at 06:57:36PM +0800, zhong jiang wrote:
>>>> The iterator in for_each_set_bit is never null, therefore, remove
>>>> the redundant conditional judgment.
>>>>
>>>> Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
>>>> ---
>>>> drivers/iio/humidity/am2315.c | 3 +--
>>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/iio/humidity/am2315.c b/drivers/iio/humidity/am2315.c
>>>> index 7d8669d..dc12e37 100644
>>>> --- a/drivers/iio/humidity/am2315.c
>>>> +++ b/drivers/iio/humidity/am2315.c
>>>> @@ -176,8 +176,7 @@ static irqreturn_t am2315_trigger_handler(int irq, void *p)
>>>> i = 0;
>>>> for_each_set_bit(bit, indio_dev->active_scan_mask,
>>>> indio_dev->masklength) {
>>>> - data->buffer[i] = (bit ? sensor_data.temp_data :
>>>> - sensor_data.hum_data);
>>>> + data->buffer[i] = sensor_data.temp_data;
>>> No, this seems wrong!
>>>
>>> We have buffer support to either take both readings(temp & humid)
>>> simultaneously, or only single channel using specified scan mask.
>> Key think is that bit most definitely can be 0 if the 0th bit is set.
>> This isn't a null check at all.
>>
>> I'm curious, was this a by inspection case or did some script throw
>> this one up?
> Hi, Jonathan
>
> bit is a iterator that find the non-zero bit in indio_dev->active_scan_mask. if all bit is
> zero , it should return the masklength.
That's my stupid fault. The patch is totally wrong.:-(

Thanks,
zhong jiang
> Yep. I find the issue with the help of Coccinelle.
>
> Thanks
> zhong jiang
>> Thanks,
>>
>> Jonathan
>>
>>> Patch title should be:
>>>
>>> "iio: humidity: am2315: .... .. "
>>>
>>>
>>> Thanks
>> .
>>
>
>
> .
>