Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

Caesar Wang
2015-12-20T07:50:27Z

在 2015年12月04日 04:19, Dmitry Torokhov 写道:
> On Thu, Dec 03, 2015 at 04:48:40PM +0800, Caesar Wang wrote:
>> As the Dan report the smatch check the thermal driver warning:
>> drivers/thermal/rockchip_thermal.c:551 rockchip_configure_from_dt()
>> warn: impossible condition '(thermal->tshut_temp > ((~0 >> 1))) =>
>> (s32min-s32max > s32max)'
>>
>> Let's we remove the imposssible condition Since the Temperature is
>> currently represented as int not long in the thermal driver.
>>
>> Fixes: commit 437df2172e8d
>> ("thermal: rockchip: consistently use int for temperatures")
>>
>> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>>
>> ---
>>
>> Changes in v3:
>> - As Brian comments on https://patchwork.kernel.org/patch/7580661/,
>> let's remove the impossible condition.
>>
>> Changes in v2: None
>> Changes in v1: None
>>
>> drivers/thermal/rockchip_thermal.c | 6 ------
>> 1 file changed, 6 deletions(-)
>>
>> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
>> index ae796ec..611de00 100644
>> --- a/drivers/thermal/rockchip_thermal.c
>> +++ b/drivers/thermal/rockchip_thermal.c
>> @@ -549,12 +549,6 @@ static int rockchip_configure_from_dt(struct device *dev,
>> thermal->tshut_temp = shut_temp;
>> }
>>
>> - if (thermal->tshut_temp > INT_MAX) {
>> - dev_err(dev, "Invalid tshut temperature specified: %d\n",
>> - thermal->tshut_temp);
>> - return -ERANGE;
>> - }
> Well, that is not entirely correct. The value that we read from DT is
> u32, but we convert it down to int. I believe you want to move the check
> up so that you do:
>
> } else if (tshut_temp > INT_MAX) {
> dev_err(dev, "Invalid tshut temperature specified: %d\n",
> thermal->tshut_temp);
> return -ERANGE;
> } else {
> thermal->tshut_temp = shut_temp;
> }

Okay,
that's seem the following wll be resonable since the checkcode is a warning.

if (of_property_read_u32(np, "rockchip,hw-tshut-temp", &shut_temp)) {
dev_warn(dev,
"Missing tshut temp property, using default %d\n",
thermal->chip->tshut_temp);
thermal->tshut_temp = thermal->chip->tshut_temp;
} else {
if (tshut_temp > INT_MAX) {
dev_err(dev, "Invalid tshut temperature specified: %d\n",
tshut_temp);
return -ERANGE;
}
thermal->tshut_temp = shut_temp;
}

Thanks,

> Thanks.
>