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

Dmitry Torokhov
2015-12-03T20:19:13Z

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;
}

Thanks.

--
Dmitry