netdev - Re: [net 5/6] i40e: better return values

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Message-Id: <20130924.101231.1193830264265403478.davem@davemloft.net>
Date:	Tue, 24 Sep 2013 10:12:31 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	joe@...ches.com
Cc:	jeffrey.t.kirsher@...el.com, jesse.brandeburg@...el.com,
	netdev@...r.kernel.org, gospo@...hat.com, sassmann@...hat.com
Subject: Re: [net 5/6] i40e: better return values

From: Joe Perches <joe@...ches.com>
Date: Tue, 24 Sep 2013 04:34:46 -0700

> On Tue, 2013-09-24 at 02:45 -0700, Jeff Kirsher wrote:
> 
>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> []
>> @@ -3339,9 +3345,7 @@ static u8 i40e_dcb_get_num_tc(struct i40e_dcbx_config *dcbcfg)
>>  	/* Traffic class index starts from zero so
>>  	 * increment to return the actual count
>>  	 */
>> -	num_tc++;
>> -
>> -	return num_tc;
>> +	return num_tc++;
> 
> Ick.  post_increment problem.
> 
> 	return ++num_tc;
> 
> There's nothing wrong with the original code
> unless this is a bugfix which should be documented
> better than "better return values".

Agreed, this style of coding is asking for a bug.

If you want to return "num_tc PLUS ONE" just say that:

	return num_tc + 1;

Why even use pre/post increment when the variable has no other
use than as a return value?
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