linux-kernel - Re: [PATCH] sound/soc/at32: Useless NULL test

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Date:	Fri, 26 Sep 2008 15:00:23 +0100
From:	Mark Brown <broonie@...ena.org.uk>
To:	Julien Brunel <brunel@...u.dk>
Cc:	tiwai@...e.de, Geoffrey Wossum <geoffrey@...er.net>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] sound/soc/at32: Useless NULL test

On Fri, Sep 26, 2008 at 03:23:46PM +0200, Julien Brunel wrote:

> The test (ssc != NULL) can only be reached if the call to the function
> ssc_request, the result of which ssc is assigned, succeeds. Moreover,
> statements assign NULL to ssc just before a return, which is useless
> since it is a local variable. So, we suggest to delete the test and
> the two assignments.

Acked-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>

For future reference if you're submitting other similar things (which I
guess you will given that you've got a tool to check for this stuff)
it'd be helpful if you could rewrite the explanation for the NULL test
to be something like:

    The test (ssc != NULL) is redundant since it can only be reached
    when ssc is guaranteed to have been set to a valid ssc.

which is much easier to parse.

> diff -u -p a/sound/soc/at32/playpaq_wm8510.c b/sound/soc/at32/playpaq_wm8510.c
> --- a/sound/soc/at32/playpaq_wm8510.c
> +++ b/sound/soc/at32/playpaq_wm8510.c
> @@ -405,7 +405,6 @@ static int __init playpaq_asoc_init(void
>  	ssc = ssc_request(0);
>  	if (IS_ERR(ssc)) {
>  		ret = PTR_ERR(ssc);
> -		ssc = NULL;
>  		goto err_ssc;
>  	}
>  	ssc_p->ssc = ssc;
> @@ -476,10 +475,7 @@ err_pll0:
>  		_gclk0 = NULL;
>  	}
>  err_gclk0:
> -	if (ssc != NULL) {
> -		ssc_free(ssc);
> -		ssc = NULL;
> -	}
> +	ssc_free(ssc);
--
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