[PATCH] clk: renesas: rcar-usb2-clock-sel: Fix error handling in rcar_usb2_clock_sel_probe

[PATCH] clk: renesas: rcar-usb2-clock-sel: Fix error handling in rcar_usb2_clock_sel_probe

[Dinghao Liu]

When clk_get_rate() fails, a pairing PM usage counter decrement
and disable is required to prevent refcount leak. It's the same
for the subsequent error paths. When of_clk_add_hw_provider()
fails, we need to unregister clk_hw.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/clk/renesas/rcar-usb2-clock-sel.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/renesas/rcar-usb2-clock-sel.c b/drivers/clk/renesas/rcar-usb2-clock-sel.c
index 3abafd78f7c8..ad7bd50b9d1b 100644
--- a/drivers/clk/renesas/rcar-usb2-clock-sel.c
+++ b/drivers/clk/renesas/rcar-usb2-clock-sel.c
@@ -180,7 +180,8 @@ static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
 
 	if (!priv->extal && !priv->xtal) {
 		dev_err(dev, "This driver needs usb_extal or usb_xtal\n");
-		return -ENOENT;
+		ret = -ENOENT;
+		goto pm_put;
 	}
 
 	platform_set_drvdata(pdev, priv);
@@ -194,10 +195,23 @@ static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
 	priv->hw.init = &init;
 
 	clk = clk_register(NULL, &priv->hw);
-	if (IS_ERR(clk))
-		return PTR_ERR(clk);
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		goto pm_put;
+	}
+
+	ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
+	if (ret)
+		goto clk_unregister;
+
+	return 0;
 
-	return of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
+clk_unregister:
+	clk_hw_unregister(&priv->hw);
+pm_put:
+	pm_runtime_put(dev);
+	pm_runtime_disable(dev);
+	return ret;
 }
 
 static const struct dev_pm_ops rcar_usb2_clock_sel_pm_ops = {
-- 
2.17.1

Re: [PATCH] clk: renesas: rcar-usb2-clock-sel: Fix error handling in rcar_usb2_clock_sel_probe

[Geert Uytterhoeven]

Hi Dinghao,

On Mon, Apr 12, 2021 at 9:51 AM Dinghao Liu <dinghao.liu@zju.edu.cn> wrote:
> When clk_get_rate() fails, a pairing PM usage counter decrement
> and disable is required to prevent refcount leak. It's the same
> for the subsequent error paths. When of_clk_add_hw_provider()
> fails, we need to unregister clk_hw.
>
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>

Thanks for your patch, which looks correct to me.

> --- a/drivers/clk/renesas/rcar-usb2-clock-sel.c
> +++ b/drivers/clk/renesas/rcar-usb2-clock-sel.c
> @@ -180,7 +180,8 @@ static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
>
>         if (!priv->extal && !priv->xtal) {
>                 dev_err(dev, "This driver needs usb_extal or usb_xtal\n");
> -               return -ENOENT;
> +               ret = -ENOENT;
> +               goto pm_put;
>         }

As the code above doesn't rely on the device being powered yet, you
could move the pm_runtime_{enable,get_sync}() calls below the clock
checks instead.

>
>         platform_set_drvdata(pdev, priv);
> @@ -194,10 +195,23 @@ static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
>         priv->hw.init = &init;
>
>         clk = clk_register(NULL, &priv->hw);
> -       if (IS_ERR(clk))
> -               return PTR_ERR(clk);
> +       if (IS_ERR(clk)) {
> +               ret = PTR_ERR(clk);
> +               goto pm_put;
> +       }
> +
> +       ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
> +       if (ret)
> +               goto clk_unregister;
> +
> +       return 0;
>
> -       return of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
> +clk_unregister:
> +       clk_hw_unregister(&priv->hw);

The error path can be simplified by replacing the call to clk_register()
by a call to devm_clk_register(), to match the style of the other
initialization steps.

> +pm_put:
> +       pm_runtime_put(dev);
> +       pm_runtime_disable(dev);
> +       return ret;

This part has to stay, of course.

>  }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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