netdev - Re: [PATCH 1/3] wireless: iwlwifi: use bool instead of int

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Date:   Wed, 04 Oct 2017 19:39:19 +0300
From:   Luciano Coelho <luciano.coelho@...el.com>
To:     Joe Perches <joe@...ches.com>,
        Christoph Böhmwalder 
        <christoph@...hmwalder.at>, johannes.berg@...el.com,
        emmanuel.grumbach@...el.com, kvalo@...eaurora.org
Cc:     linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] wireless: iwlwifi: use bool instead of int

On Wed, 2017-10-04 at 09:26 -0700, Joe Perches wrote:
> On Wed, 2017-10-04 at 17:56 +0200, Christoph Böhmwalder wrote:
> > Change a usage of int in a boolean context to use the bool type
> > instead, as it
> > makes the intent of the function clearer and helps clarify its
> > semantics.
> > 
> > Also eliminate the if/else and just return the boolean result
> > directly,
> > making the code more readable.
> > 
> > Signed-off-by: Christoph Böhmwalder <christoph@...hmwalder.at>
> > ---
> >  drivers/net/wireless/intel/iwlwifi/iwl-phy-db.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-phy-db.c
> > b/drivers/net/wireless/intel/iwlwifi/iwl-phy-db.c
> > index b7cd813ba70f..0eb815ae97e8 100644
> > --- a/drivers/net/wireless/intel/iwlwifi/iwl-phy-db.c
> > +++ b/drivers/net/wireless/intel/iwlwifi/iwl-phy-db.c
> > @@ -267,14 +267,12 @@ int iwl_phy_db_set_section(struct iwl_phy_db
> > *phy_db,
> >  }
> >  IWL_EXPORT_SYMBOL(iwl_phy_db_set_section);
> >  
> > -static int is_valid_channel(u16 ch_id)
> > +static bool is_valid_channel(u16 ch_id)
> >  {
> > -	if (ch_id <= 14 ||
> > -	    (36 <= ch_id && ch_id <= 64 && ch_id % 4 == 0) ||
> > -	    (100 <= ch_id && ch_id <= 140 && ch_id % 4 == 0) ||
> > -	    (145 <= ch_id && ch_id <= 165 && ch_id % 4 == 1))
> > -		return 1;
> > -	return 0;
> > +	return (ch_id <= 14 ||
> > +	       (36 <= ch_id && ch_id <= 64 && ch_id % 4 == 0) ||
> > +	       (100 <= ch_id && ch_id <= 140 && ch_id % 4 == 0) ||
> > +	       (145 <= ch_id && ch_id <= 165 && ch_id % 4 == 1));
> >  }
> 
> This might be more intelligble as separate tests
> 
> static bool is_valid_channel(u16 ch_id)
> {
> 	if (ch_id <= 14)
> 		return true;
> 
> 	if ((ch_id % 4 == 0) &&
> 	    ((ch_id >= 36 && ch_id <= 64) ||
> 	     (ch_id >= 100 && ch_id <= 140)))
> 		return true;
> 
> 	if ((ch_id % 4 == 1) &&
> 	    (chid >= 145 && ch_id <= 165))
> 		return true;
> 
> 	return false;
> }
> 
> The compiler should produce the same object code.

Yeah, it may be a bit easier to read, but I don't want to start getting
"fixes" to working and reasonable code.  There's nothing wrong with the
existing function (except maybe for the int vs. boolean) so let's not
change it.

A good time to change this would be the next time someone adds yet
another range of valid channels here. ;)

--
Luca.