linux-kernel - Re: [PATCH 2/3] gpio: mpc8xxx: Fix a potential double iounmap call in 'mpc8xxx

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Message-ID: <CAMpxmJX+diO-d-0sxFheMyPYJGxun6QOzddP-hrnU=ac2hSCKw@mail.gmail.com>
Date:   Tue, 31 Aug 2021 12:10:58 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        alexandru.marginean@....com, Laurentiu.Tudor@....com,
        Hui Song <hui.song_1@....com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Ran Wang <ran.wang_1@....com>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH 2/3] gpio: mpc8xxx: Fix a potential double iounmap call in 'mpc8xxx_probe()'

On Fri, Aug 20, 2021 at 5:38 PM Christophe JAILLET
<christophe.jaillet@...adoo.fr> wrote:
>
> Commit 76c47d1449fc ("gpio: mpc8xxx: Add ACPI support") has switched to a
> managed version when dealing with 'mpc8xxx_gc->regs'. So the corresponding
> 'iounmap()' call in the error handling path and in the remove should be
> removed to avoid a double unmap.
>
> This also allows some simplification in the probe. All the error handling
> paths related to managed resources can be direct returns and a NULL check
> in what remains in the error handling path can be removed.
>
> Fixes: 76c47d1449fc ("gpio: mpc8xxx: Add ACPI support")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
>  drivers/gpio/gpio-mpc8xxx.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
> index 241bcc80612e..fa4aaeced3f1 100644
> --- a/drivers/gpio/gpio-mpc8xxx.c
> +++ b/drivers/gpio/gpio-mpc8xxx.c
> @@ -332,7 +332,7 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>                                  mpc8xxx_gc->regs + GPIO_DIR, NULL,
>                                  BGPIOF_BIG_ENDIAN);
>                 if (ret)
> -                       goto err;
> +                       return ret;
>                 dev_dbg(&pdev->dev, "GPIO registers are LITTLE endian\n");
>         } else {
>                 ret = bgpio_init(gc, &pdev->dev, 4,
> @@ -342,7 +342,7 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>                                  BGPIOF_BIG_ENDIAN
>                                  | BGPIOF_BIG_ENDIAN_BYTE_ORDER);
>                 if (ret)
> -                       goto err;
> +                       return ret;
>                 dev_dbg(&pdev->dev, "GPIO registers are BIG endian\n");
>         }
>
> @@ -384,7 +384,7 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>         if (ret) {
>                 dev_err(&pdev->dev,
>                         "GPIO chip registration failed with status %d\n", ret);
> -               goto err;
> +               return ret;
>         }
>
>         mpc8xxx_gc->irqn = platform_get_irq(pdev, 0);
> @@ -416,9 +416,7 @@ static int mpc8xxx_probe(struct platform_device *pdev)
>
>         return 0;
>  err:
> -       if (mpc8xxx_gc->irq)
> -               irq_domain_remove(mpc8xxx_gc->irq);
> -       iounmap(mpc8xxx_gc->regs);
> +       irq_domain_remove(mpc8xxx_gc->irq);
>         return ret;
>  }
>
> @@ -432,7 +430,6 @@ static int mpc8xxx_remove(struct platform_device *pdev)
>         }
>
>         gpiochip_remove(&mpc8xxx_gc->gc);
> -       iounmap(mpc8xxx_gc->regs);
>
>         return 0;
>  }
> --
> 2.30.2
>

Applied, thanks!

Bart