linux-kernel - Re: [PATCH] rtlwifi: rtl8192cu: Remove variable self-assignment in rf.c

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Message-ID: <1518052003.2680.1.camel@realtek.com>
Date:   Thu, 8 Feb 2018 01:06:43 +0000
From:   Pkshih <pkshih@...ltek.com>
To:     "mka@...omium.org" <mka@...omium.org>,
        "Larry.Finger@...inger.net" <Larry.Finger@...inger.net>
CC:     "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "kvalo@...eaurora.org" <kvalo@...eaurora.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "craigb@...omium.org" <craigb@...omium.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "groeck@...omium.org" <groeck@...omium.org>,
        "teravest@...omium.org" <teravest@...omium.org>
Subject: Re: [PATCH] rtlwifi: rtl8192cu: Remove variable self-assignment in rf.c

On Wed, 2018-02-07 at 12:51 -0800, Matthias Kaehlcke wrote:
> El Wed, Feb 07, 2018 at 02:35:59PM -0600 Larry Finger ha dit:
> 
> > On 02/07/2018 02:26 PM, Matthias Kaehlcke wrote:
> > > In _rtl92c_get_txpower_writeval_by_regulatory() the variable writeVal
> > > is assigned to itself in an if ... else statement, apparently only to
> > > document that the branch condition is handled and that a previously read
> > > value should be returned unmodified. The self-assignment causes clang to
> > > raise the following warning:
> > > 
> > > drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c:304:13:
> > >    error: explicitly assigning value of variable of type 'u32'
> > >      (aka 'unsigned int') to itself [-Werror,-Wself-assign]
> > >    writeVal = writeVal;
> > > 
> > > Replace the self-assignment with a semicolon, which still serves to
> > > document the 'handling' of the branch condition.
> > > 
> > > Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
> > > ---
> > >   drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c
> b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c
> > > index 9cff6bc4049c..4db92496c122 100644
> > > --- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c
> > > +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/rf.c
> > > @@ -301,7 +301,7 @@ static void _rtl92c_get_txpower_writeval_by_regulatory(struct ieee80211_hw
> *hw,
> > >   			writeVal = writeVal - 0x06060606;
> > >   		else if (rtlpriv->dm.dynamic_txhighpower_lvl ==
> > >   			 TXHIGHPWRLEVEL_BT2)
> > > -			writeVal = writeVal;
> > > +			;
> > >   		*(p_outwriteval + rf) = writeVal;
> > >   	}
> > >   }
> > > 
> > 
> > As the branch condition does nothing, why not remove it and save the
> > compiler's optimizer a bit of work? The code looks strange, but it matches
> > the rest of Realtek's USB drivers.

Agree Larry's comment.

> 
> Sure, I am happy to change it to whatever the authors/maintainers prefer.
> 
> I'll wait a bit before respinning for if others feel strongly about
> keeping the branch.
> 
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