linux-kernel - Re: [PATCH] drm/exynos: dsi: Remove bridge node reference in error handling path in probe function

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Date:   Wed, 13 May 2020 10:45:34 +0900
From:   Inki Dae <inki.dae@...sung.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        jy0922.shim@...sung.com, sw0312.kim@...sung.com,
        kyungmin.park@...sung.com, airlied@...ux.ie, daniel@...ll.ch,
        kgene@...nel.org, krzk@...nel.org
Cc:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] drm/exynos: dsi: Remove bridge node reference in error
 handling path in probe function

Hi,

20. 5. 11. 오전 12:48에 Christophe JAILLET 이(가) 쓴 글:
> 'exynos_dsi_parse_dt()' takes a reference to 'dsi->in_bridge_node'.
> This must be released in the error handling path.
> 
> This patch is similar to commit 70505c2ef94b ("drm/exynos: dsi: Remove bridge node reference in removal")
> which fixed the issue in the remove function.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> A Fixes tag could be required, but I've not been able to figure out which
> one to use.
> 
> I think that moving 'exynos_dsi_parse_dt()' in the probe could simplify
> the error handling in the probe function. However, I don't know this code
> well enough to play this game. So better safe than sorry.
> So I've kept the logic in place and added goto everywhere. :(

You could move exynos_dsi_parse_dt() call to the end of the probe function to handle the error simply.
dsi->in_bridge_node is accessed in bind function and the probe function is called before the bind call.

Could you rework and post it again?

Thanks,
Inki Dae

> ---
>  drivers/gpu/drm/exynos/exynos_drm_dsi.c | 28 ++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index 902938d2568f..2aa74c3dc733 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -1770,14 +1770,17 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  	if (ret) {
>  		if (ret != -EPROBE_DEFER)
>  			dev_info(dev, "failed to get regulators: %d\n", ret);
> -		return ret;
> +		goto err_put_in_bridge_node;
>  	}
>  
>  	dsi->clks = devm_kcalloc(dev,
>  			dsi->driver_data->num_clks, sizeof(*dsi->clks),
>  			GFP_KERNEL);
> -	if (!dsi->clks)
> -		return -ENOMEM;
> +	if (!dsi->clks) {
> +		ret = -ENOMEM;
> +		goto err_put_in_bridge_node;
> +	}
> +
>  
>  	for (i = 0; i < dsi->driver_data->num_clks; i++) {
>  		dsi->clks[i] = devm_clk_get(dev, clk_names[i]);
> @@ -1791,7 +1794,8 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  
>  			dev_info(dev, "failed to get the clock: %s\n",
>  					clk_names[i]);
> -			return PTR_ERR(dsi->clks[i]);
> +			ret = PTR_ERR(dsi->clks[i]);
> +			goto err_put_in_bridge_node;
>  		}
>  	}
>  
> @@ -1799,19 +1803,22 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  	dsi->reg_base = devm_ioremap_resource(dev, res);
>  	if (IS_ERR(dsi->reg_base)) {
>  		dev_err(dev, "failed to remap io region\n");
> -		return PTR_ERR(dsi->reg_base);
> +		ret = PTR_ERR(dsi->reg_base);
> +		goto err_put_in_bridge_node;
>  	}
>  
>  	dsi->phy = devm_phy_get(dev, "dsim");
>  	if (IS_ERR(dsi->phy)) {
>  		dev_info(dev, "failed to get dsim phy\n");
> -		return PTR_ERR(dsi->phy);
> +		ret = PTR_ERR(dsi->phy);
> +		goto err_put_in_bridge_node;
>  	}
>  
>  	dsi->irq = platform_get_irq(pdev, 0);
>  	if (dsi->irq < 0) {
>  		dev_err(dev, "failed to request dsi irq resource\n");
> -		return dsi->irq;
> +		ret = dsi->irq;
> +		goto err_put_in_bridge_node;
>  	}
>  
>  	irq_set_status_flags(dsi->irq, IRQ_NOAUTOEN);
> @@ -1820,7 +1827,7 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  					dev_name(dev), dsi);
>  	if (ret) {
>  		dev_err(dev, "failed to request dsi irq\n");
> -		return ret;
> +		goto err_put_in_bridge_node;
>  	}
>  
>  	platform_set_drvdata(pdev, &dsi->encoder);
> @@ -1828,6 +1835,11 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  	pm_runtime_enable(dev);
>  
>  	return component_add(dev, &exynos_dsi_component_ops);
> +
> +err_put_in_bridge_node:
> +	of_node_put(dsi->in_bridge_node);
> +
> +	return ret;
>  }
>  
>  static int exynos_dsi_remove(struct platform_device *pdev)
>