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

From: [email-masked] (Dmitry Torokhov)
Date: Thu, 3 Dec 2015 12:19:08 -0800

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 <[email-masked]>
> Signed-off-by: Caesar Wang <[email-masked]>
> 
> ---
> 
> 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;
	}

Thanks.

-- 
Dmitry