Re: [PATCH 13/23] interconnect: qcom: sm8550: fix registration race

From: Abel Vesa <abel.vesa@linaro.org>
To: Johan Hovold <johan+linaro@kernel.org>
Cc: "Georgi Djakov" <djakov@kernel.org>,
	"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>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Sylwester Nawrocki" <s.nawrocki@samsung.com>,
	"Artur Świgoń" <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
Subject: Re: [PATCH 13/23] interconnect: qcom: sm8550: fix registration race
Date: Wed, 1 Feb 2023 12:20:56 +0200	[thread overview]
Message-ID: <Y9o9CGeJ4W2Pm5fG@linaro.org> (raw)
In-Reply-To: <20230201101559.15529-14-johan+linaro@kernel.org>

On 23-02-01 11:15:49, 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.

Sounds good to me.

> 
> Fixes: e6f0d6a30f73 ("interconnect: qcom: Add SM8550 interconnect provider driver")
> Cc: Abel Vesa <abel.vesa@linaro.org>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>

Reviewed-by: Abel Vesa <abel.vesa@linaro.org>

> ---
>  drivers/interconnect/qcom/sm8550.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/interconnect/qcom/sm8550.c b/drivers/interconnect/qcom/sm8550.c
> index 54fa027ab961..7ab492ca8fe0 100644
> --- a/drivers/interconnect/qcom/sm8550.c
> +++ b/drivers/interconnect/qcom/sm8550.c
> @@ -2197,9 +2197,10 @@ static int qnoc_probe(struct platform_device *pdev)
>  	provider->pre_aggregate = qcom_icc_pre_aggregate;
>  	provider->aggregate = qcom_icc_aggregate;
>  	provider->xlate_extended = qcom_icc_xlate_extended;
> -	INIT_LIST_HEAD(&provider->nodes);
>  	provider->data = data;
>  
> +	icc_provider_init(provider);
> +
>  	qp->dev = &pdev->dev;
>  	qp->bcms = desc->bcms;
>  	qp->num_bcms = desc->num_bcms;
> @@ -2208,12 +2209,6 @@ static int qnoc_probe(struct platform_device *pdev)
>  	if (IS_ERR(qp->voter))
>  		return PTR_ERR(qp->voter);
>  
> -	ret = icc_provider_add(provider);
> -	if (ret) {
> -		dev_err_probe(&pdev->dev, ret,
> -			      "error adding interconnect provider\n");
> -		return ret;
> -	}
>  
>  	for (i = 0; i < qp->num_bcms; i++)
>  		qcom_icc_bcm_init(qp->bcms[i], &pdev->dev);
> @@ -2227,7 +2222,7 @@ static int qnoc_probe(struct platform_device *pdev)
>  		node = icc_node_create(qnodes[i]->id);
>  		if (IS_ERR(node)) {
>  			ret = PTR_ERR(node);
> -			goto err;
> +			goto err_remove_nodes;
>  		}
>  
>  		node->name = qnodes[i]->name;
> @@ -2241,12 +2236,17 @@ static int qnoc_probe(struct platform_device *pdev)
>  	}
>  	data->num_nodes = num_nodes;
>  
> +	ret = icc_provider_register(provider);
> +	if (ret)
> +		goto err_remove_nodes;
> +
>  	platform_set_drvdata(pdev, qp);
>  
>  	return 0;
> -err:
> +
> +err_remove_nodes:
>  	icc_nodes_remove(provider);
> -	icc_provider_del(provider);
> +
>  	return ret;
>  }
>  
> @@ -2254,8 +2254,8 @@ static int qnoc_remove(struct platform_device *pdev)
>  {
>  	struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
>  
> +	icc_provider_deregister(&qp->provider);
>  	icc_nodes_remove(&qp->provider);
> -	icc_provider_del(&qp->provider);
>  
>  	return 0;
>  }
> -- 
> 2.39.1
> 

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