linux-kernel - Re: [PATCH] soc: amlogic: canvas: Fix meson_canvas_get when probe failed

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Message-ID: <CAMO6nawKrH3d2X=TikdJy8yjiPyuJJRnpaBjyfPYuRx3d=7vVA@mail.gmail.com>
Date:   Mon, 4 Feb 2019 10:59:34 +0100
From:   Maxime Jourdan <mjourdan@...libre.com>
To:     Neil Armstrong <narmstrong@...libre.com>
Cc:     Kevin Hilman <khilman@...libre.com>,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] soc: amlogic: canvas: Fix meson_canvas_get when probe failed

Hi Neil,
On Mon, Feb 4, 2019 at 10:49 AM Neil Armstrong <narmstrong@...libre.com> wrote:
>
> When probe fails, a platforn_device is still associated to the node,
> but dev_get_drvdata() returns NULL.
>
> Handle this case by returning a consistent error.
>
> Fixes: d4983983d987 ("soc: amlogic: add meson-canvas driver")
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> ---
>  drivers/soc/amlogic/meson-canvas.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>
> This fix depends on "soc: amlogic: add missing of_node_put()" at [1]
>
> [1] https://patchwork.kernel.org/patch/10794545/
>
> diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
> index 87a6c6e23591..151aa84bc593 100644
> --- a/drivers/soc/amlogic/meson-canvas.c
> +++ b/drivers/soc/amlogic/meson-canvas.c
> @@ -51,6 +51,7 @@ struct meson_canvas *meson_canvas_get(struct device *dev)
>  {
>         struct device_node *canvas_node;
>         struct platform_device *canvas_pdev;
> +       struct meson_canvas *canvas;
>
>         canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
>         if (!canvas_node)
> @@ -63,7 +64,17 @@ struct meson_canvas *meson_canvas_get(struct device *dev)
>         }
>
>         of_node_put(canvas_node);
> -       return dev_get_drvdata(&canvas_pdev->dev);
> +
> +       /*
> +        * If priv is NULL, it's probably because the canvas hasn't
> +        * properly initialized. Bait out with -EINVAL because, in the

Bait -> Bail ?

> +        * current state, this driver probe cannot return -EPROBE_DEFER
> +        */
> +       canvas = dev_get_drvdata(&canvas_pdev->dev);
> +       if (!canvas)
> +               return ERR_PTR(-EINVAL);
> +
> +       return canvas;
>  }
>  EXPORT_SYMBOL_GPL(meson_canvas_get);
>
> --
> 2.20.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Thanks for the patch, I missed the fact that a driver could have a
pdev yet with a failed probe.

Reviewed-by: Maxime Jourdan <mjourdan@...libre.com>

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