linux-kernel - Re: [RFC PATCH v4 2/2] clk: Use devm

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Date:   Thu, 27 Feb 2020 14:36:29 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Marc Gonzalez <marc.w.gonzalez@...e.fr>
Cc:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
        Russell King <linux@...linux.org.uk>,
        Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Robin Murphy <robin.murphy@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rafael Wysocki <rjw@...ysocki.net>,
        Suzuki Poulose <suzuki.poulose@....com>,
        Mark Rutland <mark.rutland@....com>,
        linux-clk <linux-clk@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH v4 2/2] clk: Use devm_add in managed functions

Hi Marc,

Thanks for your patch!

On Wed, Feb 26, 2020 at 4:55 PM Marc Gonzalez <marc.w.gonzalez@...e.fr> wrote:
> Using the helper produces simpler code, and smaller object size.
> E.g. with gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu:
>
>     text           data     bss     dec     hex filename
> -   1708             80       0    1788     6fc drivers/clk/clk-devres.o
> +   1524             80       0    1604     644 drivers/clk/clk-devres.o

And the size reduction could have been even more ;-)

> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@...e.fr>

> --- a/drivers/clk/clk-devres.c
> +++ b/drivers/clk/clk-devres.c

> @@ -55,25 +51,17 @@ static void devm_clk_bulk_release(struct device *dev, void *res)
>  static int __devm_clk_bulk_get(struct device *dev, int num_clks,
>                                struct clk_bulk_data *clks, bool optional)
>  {
> -       struct clk_bulk_devres *devres;
>         int ret;
>
> -       devres = devres_alloc(devm_clk_bulk_release,
> -                             sizeof(*devres), GFP_KERNEL);
> -       if (!devres)
> -               return -ENOMEM;
> -
>         if (optional)
>                 ret = clk_bulk_get_optional(dev, num_clks, clks);
>         else
>                 ret = clk_bulk_get(dev, num_clks, clks);
> -       if (!ret) {
> -               devres->clks = clks;
> -               devres->num_clks = num_clks;
> -               devres_add(dev, devres);
> -       } else {
> -               devres_free(devres);
> -       }
> +
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_vadd(dev, my_clk_bulk_put, clk_bulk_args, num_clks, clks);
>
>         return ret;

return devm_vadd(...);

>  }

> @@ -128,30 +109,22 @@ static int devm_clk_match(struct device *dev, void *res, void *data)
>
>  void devm_clk_put(struct device *dev, struct clk *clk)
>  {
> -       int ret;
> -
> -       ret = devres_release(dev, devm_clk_release, devm_clk_match, clk);
> -
> -       WARN_ON(ret);
> +       WARN_ON(devres_release(dev, my_clk_put, devm_clk_match, clk));

Getting rid of "ret" is an unrelated change, which actually increases
kernel size, as the WARN_ON() parameter is stringified for the warning
message.

The rest looks good, so with the above fixed:
Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

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