Re: [patch v2] iio: adc: at91: signedness bug in at91_adc_get_trigger_value_by_name()

[Jonathan Cameron <jic23@kernel.org>]

On 11/06/14 15:41, Alexandre Belloni wrote:
> On 11/06/2014 at 11:13:17 +0300, Dan Carpenter wrote :
>> at91_adc_get_trigger_value_by_name() was returning -ENOMEM truncated to
>> a positive u8 and that doesn't work.  I've changed it to int and
>> refactored it to preserve the error code.
>>
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
>
> Also, tested on an at91sam9g45ek.
I've added a tested-by as in many ways that has more weight than an
Ack (and can sit alongside it just fine)

Dan, thanks as ever!

Applied to the fixes-togreg branch of iio.git and cc'd to stable.

Jonathan

>
>> ---
>> I'm not able to compile this code.
Me neither - which makes that tested by rather handy ;)
>>
>> v2:  Preserve the -ENOMEM
>>
>> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
>> index 3b5bacd..2b6a9ce 100644
>> --- a/drivers/iio/adc/at91_adc.c
>> +++ b/drivers/iio/adc/at91_adc.c
>> @@ -510,12 +510,11 @@ static int at91_adc_channel_init(struct iio_dev *idev)
>>   	return idev->num_channels;
>>   }
>>
>> -static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
>> +static int at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
>>   					     struct at91_adc_trigger *triggers,
>>   					     const char *trigger_name)
>>   {
>>   	struct at91_adc_state *st = iio_priv(idev);
>> -	u8 value = 0;
>>   	int i;
>>
>>   	for (i = 0; i < st->trigger_number; i++) {
>> @@ -528,15 +527,16 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
>>   			return -ENOMEM;
>>
>>   		if (strcmp(trigger_name, name) == 0) {
>> -			value = triggers[i].value;
>>   			kfree(name);
>> -			break;
>> +			if (triggers[i].value == 0)
>> +				return -EINVAL;
>> +			return triggers[i].value;
>>   		}
>>
>>   		kfree(name);
>>   	}
>>
>> -	return value;
>> +	return -EINVAL;
>>   }
>>
>>   static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
>> @@ -546,14 +546,14 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
>>   	struct iio_buffer *buffer = idev->buffer;
>>   	struct at91_adc_reg_desc *reg = st->registers;
>>   	u32 status = at91_adc_readl(st, reg->trigger_register);
>> -	u8 value;
>> +	int value;
>>   	u8 bit;
>>
>>   	value = at91_adc_get_trigger_value_by_name(idev,
>>   						   st->trigger_list,
>>   						   idev->trig->name);
>> -	if (value == 0)
>> -		return -EINVAL;
>> +	if (value < 0)
>> +		return value;
>>
>>   	if (state) {
>>   		st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
>