Message-ID: <63d1da22-84b0-1b02-2766-99cc298a8ac4@linaro.org>
Date:   Fri, 3 Feb 2023 03:49:56 +0100
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Subject: Re: [PATCH 04/23] interconnect: imx: fix registration race
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To:     Johan Hovold <johan+linaro@kernel.org>,
        Georgi Djakov <djakov@kernel.org>
Cc:     Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Sylwester Nawrocki <s.nawrocki@samsung.com>,
        =?UTF-8?B?QXJ0dXIgxZp3aWdvxYQ=?= <a.swigon@samsung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-arm-msm@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Leonard Crestez <leonard.crestez@nxp.com>,
        Alexandre Bailon <abailon@baylibre.com>
References: <20230201101559.15529-1-johan+linaro@kernel.org>
 <20230201101559.15529-5-johan+linaro@kernel.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <20230201101559.15529-5-johan+linaro@kernel.org>
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Precedence: bulk


On 1.02.2023 11:15, Johan Hovold wrote:
> The current interconnect provider registration interface is inherently
> racy as nodes are not added until the after adding the provider. This
> can specifically cause racing DT lookups to fail.
> 
> Switch to using the new API where the provider is not registered until
> after it has been fully initialised.
> 
> Fixes: f0d8048525d7 ("interconnect: Add imx core driver")
> Cc: stable@vger.kernel.org      # 5.8
> Cc: Leonard Crestez <leonard.crestez@nxp.com>
> Cc: Alexandre Bailon <abailon@baylibre.com>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
>  drivers/interconnect/imx/imx.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/interconnect/imx/imx.c b/drivers/interconnect/imx/imx.c
> index 823d9be9771a..979ed610f704 100644
> --- a/drivers/interconnect/imx/imx.c
> +++ b/drivers/interconnect/imx/imx.c
> @@ -295,6 +295,9 @@ int imx_icc_register(struct platform_device *pdev,
>  	provider->xlate = of_icc_xlate_onecell;
>  	provider->data = data;
>  	provider->dev = dev->parent;
> +
> +	icc_provider_init(provider);
> +
>  	platform_set_drvdata(pdev, imx_provider);
>  
>  	if (settings) {
> @@ -306,20 +309,18 @@ int imx_icc_register(struct platform_device *pdev,
>  		}
>  	}
>  
> -	ret = icc_provider_add(provider);
> -	if (ret) {
> -		dev_err(dev, "error adding interconnect provider: %d\n", ret);
> +	ret = imx_icc_register_nodes(imx_provider, nodes, nodes_count, settings);
> +	if (ret)
>  		return ret;
> -	}
>  
> -	ret = imx_icc_register_nodes(imx_provider, nodes, nodes_count, settings);
> +	ret = icc_provider_register(provider);
>  	if (ret)
> -		goto provider_del;
> +		goto err_unregister_nodes;
>  
>  	return 0;
>  
> -provider_del:
> -	icc_provider_del(provider);
> +err_unregister_nodes:
> +	imx_icc_unregister_nodes(&imx_provider->provider);
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(imx_icc_register);
> @@ -328,9 +329,8 @@ void imx_icc_unregister(struct platform_device *pdev)
>  {
>  	struct imx_icc_provider *imx_provider = platform_get_drvdata(pdev);
>  
> +	icc_provider_deregister(&imx_provider->provider);
>  	imx_icc_unregister_nodes(&imx_provider->provider);
> -
> -	icc_provider_del(&imx_provider->provider);
>  }
>  EXPORT_SYMBOL_GPL(imx_icc_unregister);
>