linux-kernel - Re: [PATCH] atmel: fix a missing check of clk

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Date:   Wed, 26 Dec 2018 09:32:24 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Kangjie Lu <kjlu@....edu>
Cc:     pakki001@....edu, Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] atmel: fix a missing check of clk_prepare

Hi,

On 25/12/2018 20:54:05-0600, Kangjie Lu wrote:
> clk_prepare() could fail, so let's check its status, and if it fails,
> issue an error message.
> 
> Signed-off-by: Kangjie Lu <kjlu@....edu>
> ---
>  drivers/misc/atmel-ssc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/atmel-ssc.c b/drivers/misc/atmel-ssc.c
> index d8e3cc2dc747..9e69d0585f49 100644
> --- a/drivers/misc/atmel-ssc.c
> +++ b/drivers/misc/atmel-ssc.c
> @@ -60,7 +60,8 @@ struct ssc_device *ssc_request(unsigned int ssc_num)
>  	ssc->user++;
>  	spin_unlock(&user_lock);
>  
> -	clk_prepare(ssc->clk);
> +	if (clk_prepare(ssc->clk))
> +		pr_err("ssc: failed to prepare clk.\n");
>  

There is no point in adding this check and yet another string to please
a static analysis tool. This is especially true because clk_prepare will
never actually fail else you wouldn't reach this code anyway.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com