linux-kernel - Re: [PATCH 2/7] thermal: of: Use scoped device node handling to simplify thermal_of_trips

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Message-ID: <20240815071538.GB350960@google.com>
Date: Thu, 15 Aug 2024 15:15:38 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Zhang Rui <rui.zhang@...el.com>, Lukasz Luba <lukasz.luba@....com>,
	Amit Kucheria <amitk@...nel.org>,
	Thara Gopinath <thara.gopinath@...il.com>,
	Thierry Reding <thierry.reding@...il.com>,
	Jonathan Hunter <jonathanh@...dia.com>,
	Vasily Khoruzhick <anarsoul@...il.com>,
	Yangtao Li <tiny.windzz@...il.com>, Chen-Yu Tsai <wens@...e.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	linux-tegra@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-sunxi@...ts.linux.dev
Subject: Re: [PATCH 2/7] thermal: of: Use scoped device node handling to
 simplify thermal_of_trips_init()

On Wed, Aug 14, 2024 at 10:17:48PM +0200, Krzysztof Kozlowski wrote:
> Obtain the device node reference with scoped/cleanup.h to reduce error
> handling and make the code a bit simpler.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> ---
>  drivers/thermal/thermal_of.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
> index a2278d4ad886..c8ded4462bb8 100644
> --- a/drivers/thermal/thermal_of.c
> +++ b/drivers/thermal/thermal_of.c
> @@ -117,10 +117,9 @@ static int thermal_of_populate_trip(struct device_node *np,
>  static struct thermal_trip *thermal_of_trips_init(struct device_node *np, int *ntrips)
>  {
>  	struct thermal_trip *tt;
> -	struct device_node *trips;
>  	int ret, count;
>  
> -	trips = of_get_child_by_name(np, "trips");
> +	struct device_node *trips __free(device_node) = of_get_child_by_name(np, "trips");
>  	if (!trips) {
>  		pr_err("Failed to find 'trips' node\n");
>  		return ERR_PTR(-EINVAL);
> @@ -129,15 +128,12 @@ static struct thermal_trip *thermal_of_trips_init(struct device_node *np, int *n
>  	count = of_get_child_count(trips);
>  	if (!count) {
>  		pr_err("No trip point defined\n");
> -		ret = -EINVAL;
> -		goto out_of_node_put;
> +		return ERR_PTR(-EINVAL);
>  	}
>  
>  	tt = kzalloc(sizeof(*tt) * count, GFP_KERNEL);
> -	if (!tt) {
> -		ret = -ENOMEM;
> -		goto out_of_node_put;
> -	}
> +	if (!tt)
> +		return ERR_PTR(-ENOMEM);
>  
>  	*ntrips = count;

Also drop the "of_node_put(trips);" in the successful path?

Once fixed,

Reviewed-by: Chen-Yu Tsai <wenst@...omium.org>

And I plan to send a patch on top of this making "tt" auto released,
thereby eliminating the error path.

>  
> @@ -155,8 +151,6 @@ static struct thermal_trip *thermal_of_trips_init(struct device_node *np, int *n
>  out_kfree:
>  	kfree(tt);
>  	*ntrips = 0;
> -out_of_node_put:
> -	of_node_put(trips);
>  
>  	return ERR_PTR(ret);
>  }
> 
> -- 
> 2.43.0
>