Message-ID: <07b3338d-1d3d-ac06-07f3-337d3df9dde8@linaro.org>
Date:   Fri, 3 Feb 2023 03:56:24 +0100
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Subject: Re: [PATCH 11/23] interconnect: qcom: msm8974: fix registration race
Content-Language: en-US
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, Brian Masney <bmasney@redhat.com>
References: <20230201101559.15529-1-johan+linaro@kernel.org>
 <20230201101559.15529-12-johan+linaro@kernel.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <20230201101559.15529-12-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: 4e60a9568dc6 ("interconnect: qcom: add msm8974 driver")
> Cc: stable@vger.kernel.org      # 5.5
> Cc: Brian Masney <bmasney@redhat.com>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
>  drivers/interconnect/qcom/msm8974.c | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/interconnect/qcom/msm8974.c b/drivers/interconnect/qcom/msm8974.c
> index 5ea192f1141d..1828deaca443 100644
> --- a/drivers/interconnect/qcom/msm8974.c
> +++ b/drivers/interconnect/qcom/msm8974.c
> @@ -692,7 +692,6 @@ static int msm8974_icc_probe(struct platform_device *pdev)
>  		return ret;
>  
>  	provider = &qp->provider;
> -	INIT_LIST_HEAD(&provider->nodes);
>  	provider->dev = dev;
>  	provider->set = msm8974_icc_set;
>  	provider->aggregate = icc_std_aggregate;
> @@ -700,11 +699,7 @@ static int msm8974_icc_probe(struct platform_device *pdev)
>  	provider->data = data;
>  	provider->get_bw = msm8974_get_bw;
>  
> -	ret = icc_provider_add(provider);
> -	if (ret) {
> -		dev_err(dev, "error adding interconnect provider: %d\n", ret);
> -		goto err_disable_clks;
> -	}
> +	icc_provider_init(provider);
>  
>  	for (i = 0; i < num_nodes; i++) {
>  		size_t j;
> @@ -712,7 +707,7 @@ static int msm8974_icc_probe(struct platform_device *pdev)
>  		node = icc_node_create(qnodes[i]->id);
>  		if (IS_ERR(node)) {
>  			ret = PTR_ERR(node);
> -			goto err_del_icc;
> +			goto err_remove_nodes;
>  		}
>  
>  		node->name = qnodes[i]->name;
> @@ -729,15 +724,16 @@ static int msm8974_icc_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_del_icc:
> +err_remove_nodes:
>  	icc_nodes_remove(provider);
> -	icc_provider_del(provider);
> -
> -err_disable_clks:
>  	clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
>  
>  	return ret;
> @@ -747,9 +743,9 @@ static int msm8974_icc_remove(struct platform_device *pdev)
>  {
>  	struct msm8974_icc_provider *qp = platform_get_drvdata(pdev);
>  
> +	icc_provider_deregister(&qp->provider);
>  	icc_nodes_remove(&qp->provider);
>  	clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
> -	icc_provider_del(&qp->provider);
>  
>  	return 0;
>  }