linux-kernel - Re: [PATCH v2] cpufreq: s5pv210: add missing of_node

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Message-ID: <20170724085216.GS352@vireshk-i7>
Date:   Mon, 24 Jul 2017 14:22:16 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Julia Lawall <Julia.Lawall@...6.fr>
Cc:     Kukjin Kim <kgene@...nel.org>, kernel-janitors@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] cpufreq: s5pv210: add missing of_node_put

On 21-07-17, 21:53, Julia Lawall wrote:
> for_each_compatible_node performs an of_node_get on each iteration, so a
> return from the loop requires an of_node_put.
> 
> The semantic patch that fixes this problem is as follows
> (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> local idexpression n;
> expression e,e1,e2;
> statement S;
> iterator i1;
> iterator name for_each_compatible_node;
> @@
> 
>  for_each_compatible_node(n,e1,e2) {
>    ...
> (
>    of_node_put(n);
> |
>    e = n
> |
>    return n;
> |
>    i1(...,n,...) S
> |
> +  of_node_put(n);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
> 
> Additionally, call of_node_put on the previous value of np, obtained from
> of_find_compatible_node, that is no longer accessible at the point of the
> for_each_compatible_node.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
> 
> ---
> 
> v2: add the of_node_put for the call to of_find_compatible_node as well.
> 
>  drivers/cpufreq/s5pv210-cpufreq.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
> index f82074e..5d31c2d 100644
> --- a/drivers/cpufreq/s5pv210-cpufreq.c
> +++ b/drivers/cpufreq/s5pv210-cpufreq.c
> @@ -602,6 +602,7 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
>  	}
>  
>  	clk_base = of_iomap(np, 0);
> +	of_node_put(np);
>  	if (!clk_base) {
>  		pr_err("%s: failed to map clock registers\n", __func__);
>  		return -EFAULT;
> @@ -612,6 +613,7 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
>  		if (id < 0 || id >= ARRAY_SIZE(dmc_base)) {
>  			pr_err("%s: failed to get alias of dmc node '%s'\n",
>  				__func__, np->name);
> +			of_node_put(np);
>  			return id;
>  		}
>  
> @@ -619,6 +621,7 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
>  		if (!dmc_base[id]) {
>  			pr_err("%s: failed to map dmc%d registers\n",
>  				__func__, id);
> +			of_node_put(np);
>  			return -EFAULT;
>  		}
>  	}

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh