linux-kernel - Re: [PATCH] sh: prevent warnings when using iounmap

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Date:   Mon, 24 Jun 2019 09:59:11 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Sam Ravnborg <sam@...nborg.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-sh list <linux-sh@...r.kernel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Will Deacon <will.deacon@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mark Brown <broonie@...nel.org>,
        Inki Dae <inki.dae@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Subject: Re: [PATCH] sh: prevent warnings when using iounmap

Hi Sam,

On Sat, Jun 22, 2019 at 1:45 PM Sam Ravnborg <sam@...nborg.org> wrote:
> When building drm/exynos for sh, as part of an allmodconfig build,
> the following warning triggered:
>
>   exynos7_drm_decon.c: In function ‘decon_remove’:
>   exynos7_drm_decon.c:769:24: warning: unused variable ‘ctx’
>     struct decon_context *ctx = dev_get_drvdata(&pdev->dev);
>
> The ctx variable is only used as argument to iounmap().
>
> In sh - allmodconfig CONFIG_MMU is not defined
> so it ended up in:
>
> \#define __iounmap(addr)        do { } while (0)
> \#define iounmap                __iounmap
>
> Fix the warning by introducing a static inline
> function for iounmap.
> This is similar to several other architectures.
>
> Signed-off-by: Sam Ravnborg <sam@...nborg.org>

Thanks for your patch!

> --- a/arch/sh/include/asm/io.h
> +++ b/arch/sh/include/asm/io.h
> @@ -369,7 +369,11 @@ static inline int iounmap_fixed(void __iomem *addr) { return -EINVAL; }
>
>  #define ioremap_nocache        ioremap
>  #define ioremap_uc     ioremap
> -#define iounmap                __iounmap
> +
> +static inline void iounmap(void __iomem *addr)
> +{
> +       __iounmap(addr);
> +}

The alternative would be to make __iounmap() static inline, which may be
better from the viewpoint of consistency within this header file.

Regardless:
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