linux-kernel - Re: [PATCH] drm/vc4: release firmware on error paths in vc4_hvs

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Message-ID: <CAPY8ntCtAdWg1yN+DgxRe3np4Nu3aDUrrdqe4Q9WeqJMtbrrAg@mail.gmail.com>
Date: Wed, 2 Apr 2025 11:34:58 +0000
From: Dave Stevenson <dave.stevenson@...pberrypi.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: Maxime Ripard <mripard@...nel.org>, Maíra Canal <mcanal@...lia.com>, 
	Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Thomas Zimmermann <tzimmermann@...e.de>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] drm/vc4: release firmware on error paths in vc4_hvs_bind()

Hi Dan

On Wed, 2 Apr 2025 at 12:00, Dan Carpenter <dan.carpenter@...aro.org> wrote:
>
> Call rpi_firmware_put() on these two error paths before returning.

Ack that there is an issue here, but it seems easier to me to move the block

        max_rate = rpi_firmware_clk_get_max_rate(firmware,
                             RPI_FIRMWARE_CORE_CLK_ID);
        rpi_firmware_put(firmware);
        if (max_rate >= 550000000)
            hvs->vc5_hdmi_enable_hdmi_20 = true;

        if (max_rate >= 600000000)
            hvs->vc5_hdmi_enable_4096by2160 = true;

        hvs->max_core_rate = max_rate;

to before we make the devm_clk_get calls. It has no dependencies on
having retrieved the clocks, and hopefully means we don't get the same
type of leaks creeping back in in future.

Thanks
  Dave

> Fixes: 2fa4ef5fb943 ("drm/vc4: hvs: Create hw_init function")
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>  drivers/gpu/drm/vc4/vc4_hvs.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
> index 4811d794001f..41e9d0aff757 100644
> --- a/drivers/gpu/drm/vc4/vc4_hvs.c
> +++ b/drivers/gpu/drm/vc4/vc4_hvs.c
> @@ -1678,6 +1678,7 @@ static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
>                 hvs->core_clk = devm_clk_get(&pdev->dev,
>                                              (vc4->gen >= VC4_GEN_6_C) ? "core" : NULL);
>                 if (IS_ERR(hvs->core_clk)) {
> +                       rpi_firmware_put(firmware);
>                         dev_err(&pdev->dev, "Couldn't get core clock\n");
>                         return PTR_ERR(hvs->core_clk);
>                 }
> @@ -1685,6 +1686,7 @@ static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
>                 hvs->disp_clk = devm_clk_get(&pdev->dev,
>                                              (vc4->gen >= VC4_GEN_6_C) ? "disp" : NULL);
>                 if (IS_ERR(hvs->disp_clk)) {
> +                       rpi_firmware_put(firmware);
>                         dev_err(&pdev->dev, "Couldn't get disp clock\n");
>                         return PTR_ERR(hvs->disp_clk);
>                 }
> --
> 2.47.2
>