linux-kernel - Re: [PATCH][thermal-next] thermal: brcmstb: remove two redundant integer range checks

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Message-ID: <20170906184046.GB35422@google.com>
Date:   Wed, 6 Sep 2017 11:40:46 -0700
From:   Brian Norris <computersforpeace@...il.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Markus Mayer <mmayer@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH][thermal-next] thermal: brcmstb: remove two redundant
 integer range checks

Hi,

On Sun, Sep 03, 2017 at 02:16:19PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The comparisons for integer low on low > INT_MAX and also
> integer high > INT_MAX are never going to be true since an
> int type cannot be greater than INT_MAX.  Remove these redundant
> checks.
> 
> Detected by: CoverityScan CID#1455245, 1455248 ("Operands don't affect
>   result (CONSTANT_EXPRESSION_RESULT)")
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/thermal/broadcom/brcmstb_thermal.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/thermal/broadcom/brcmstb_thermal.c b/drivers/thermal/broadcom/brcmstb_thermal.c
> index 87b8e7a86ee3..bcb3945feea6 100644
> --- a/drivers/thermal/broadcom/brcmstb_thermal.c
> +++ b/drivers/thermal/broadcom/brcmstb_thermal.c
> @@ -278,8 +278,6 @@ static int brcmstb_set_trips(void *data, int low, int high)
>  	dev_dbg(priv->dev, "set trips %d <--> %d\n", low, high);
>  
>  	if (low) {
> -		if (low > INT_MAX)
> -			low = INT_MAX;
>  		avs_tmon_set_trip_temp(priv, TMON_TRIP_TYPE_LOW, low);
>  		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_LOW, 1);
>  	} else {
> @@ -287,8 +285,6 @@ static int brcmstb_set_trips(void *data, int low, int high)
>  	}
>  
>  	if (high < ULONG_MAX) {

Dan's robots noticed that the above condition is not useful either (on
architectures where INT_MAX < ULONG_MAX -- i.e., all?), since 'high' is
'int', not 'unsigned long'.

Should probably fix that

s/ULONG_MAX/INT_MAX/

?

Brian

> -		if (high > INT_MAX)
> -			high = INT_MAX;
>  		avs_tmon_set_trip_temp(priv, TMON_TRIP_TYPE_HIGH, high);
>  		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_HIGH, 1);
>  	} else {
> -- 
> 2.14.1
>