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

[Caesar Wang]

å 2015å12æ04æ 04:19, Dmitry Torokhov åé:
> 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@xxxxxxxxxx>
> > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> >
> > ---
> >
> > 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.

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