linux-kernel - Re: [PATCH 09/10] pmdomain: renesas: rcar-gen4-sysc: Use scoped device node handling to simplify error paths

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Message-ID: <CAMuHMdWXUyLbypvgTrtx0mY5vF6abW8bab2poso=xn88gNqEmA@mail.gmail.com>
Date: Wed, 27 Nov 2024 14:14:05 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: Ulf Hansson <ulf.hansson@...aro.org>, Heiko Stuebner <heiko@...ech.de>, 
	Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
	Pengutronix Kernel Team <kernel@...gutronix.de>, Fabio Estevam <festevam@...il.com>, 
	Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konradybcio@...nel.org>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, Magnus Damm <magnus.damm@...il.com>, 
	linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	imx@...ts.linux.dev, linux-arm-msm@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 09/10] pmdomain: renesas: rcar-gen4-sysc: Use scoped
 device node handling to simplify error paths

Hi Krzysztof,

On Fri, Aug 23, 2024 at 2:51 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> 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>

Revisiting an old patch (the same applies to 10/10)...

> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> @@ -6,6 +6,7 @@
>   */
>
>  #include <linux/bits.h>
> +#include <linux/cleanup.h>
>  #include <linux/clk/renesas.h>
>  #include <linux/delay.h>
>  #include <linux/err.h>
> @@ -303,12 +304,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>         const struct rcar_gen4_sysc_info *info;
>         const struct of_device_id *match;
>         struct rcar_gen4_pm_domains *domains;
> -       struct device_node *np;
>         void __iomem *base;
>         unsigned int i;
>         int error;
>
> -       np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
> +       struct device_node *np __free(device_node) =
> +               of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
>         if (!np)
>                 return -ENODEV;

[...]

> @@ -369,14 +365,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>                 if (error) {
>                         pr_warn("Failed to add PM subdomain %s to parent %u\n",
>                                 area->name, area->parent);
> -                       goto out_put;
> +                       return error;
>                 }
>         }
>
>         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);

np is passed to of_genpd_add_provider_onecell(), which stores a copy
for later use, so I think it must not be released in case of success?
I.e. both the old and the new code are wrong?

>
> -out_put:
> -       of_node_put(np);
>         return error;
>  }
>  early_initcall(rcar_gen4_sysc_pd_init);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds