linux-kernel - Re: [PATCH 3/7] staging: ks7010: Remove unnecessary limit checks

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Message-ID: <20180514140622.GA13207@flashbox>
Date:   Mon, 14 May 2018 07:06:22 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     devel@...verdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/7] staging: ks7010: Remove unnecessary limit checks

On Mon, May 14, 2018 at 04:17:36PM +0300, Dan Carpenter wrote:
> On Sun, May 06, 2018 at 03:03:00PM -0700, Nathan Chancellor wrote:
> > uwrq is an unsigned 32-bit integer, it cannot be less than zero.
> > 
> > Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> > ---
> >  drivers/staging/ks7010/ks_wlan_net.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/staging/ks7010/ks_wlan_net.c b/drivers/staging/ks7010/ks_wlan_net.c
> > index e96477937f65..0c83d6fe270f 100644
> > --- a/drivers/staging/ks7010/ks_wlan_net.c
> > +++ b/drivers/staging/ks7010/ks_wlan_net.c
> > @@ -1928,7 +1928,7 @@ static int ks_wlan_set_beacon_lost(struct net_device *dev,
> >  	if (priv->sleep_mode == SLP_SLEEP)
> >  		return -EPERM;
> >  	/* for SLEEP MODE */
> > -	if (*uwrq < BEACON_LOST_COUNT_MIN || *uwrq > BEACON_LOST_COUNT_MAX)
> > +	if (*uwrq > BEACON_LOST_COUNT_MAX)
> 
> I believe Smatch is supposed to ignore this sort of code because
> comparing "if (foo < 0 || foo > max) " is pretty readable and idiomatic.
> 
> Presumably this was so we could redefine BEACON_LOST_COUNT_MIN, but it's
> fine to unused code.  The define isn't needed at all, so you can
> delete that as well.
> 
> regards,
> dan carpenter
> 

Hi Dan,

Thanks for the suggestion, I just sent a patch.

This warning came from GCC as a -Wtype-limit warning. I should have put
that in the commit message to be more clear. I will keep this in mind
for the future if I come across any more checks like this with defines.

Thanks!
Nathan Chancellor