linux-kernel - [PATCH v2 13/23] interconnect: qcom: sm8550: fix registration race

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Message-Id: <20230306075651.2449-14-johan+linaro@kernel.org>
Date:   Mon,  6 Mar 2023 08:56:41 +0100
From:   Johan Hovold <johan+linaro@...nel.org>
To:     Georgi Djakov <djakov@...nel.org>
Cc:     "Shawn Guo" <shawnguo@...nel.org>,
        "Sascha Hauer" <s.hauer@...gutronix.de>,
        "Pengutronix Kernel Team" <kernel@...gutronix.de>,
        "Fabio Estevam" <festevam@...il.com>,
        "NXP Linux Team" <linux-imx@....com>,
        "Andy Gross" <agross@...nel.org>,
        "Bjorn Andersson" <andersson@...nel.org>,
        "Konrad Dybcio" <konrad.dybcio@...aro.org>,
        "Sylwester Nawrocki" <s.nawrocki@...sung.com>,
        Artur Świgoń <a.swigon@...sung.com>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski@...aro.org>,
        "Alim Akhtar" <alim.akhtar@...sung.com>,
        "Thierry Reding" <thierry.reding@...il.com>,
        "Jonathan Hunter" <jonathanh@...dia.com>, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
        Johan Hovold <johan+linaro@...nel.org>,
        Abel Vesa <abel.vesa@...aro.org>
Subject: [PATCH v2 13/23] interconnect: qcom: sm8550: fix registration race

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: e6f0d6a30f73 ("interconnect: qcom: Add SM8550 interconnect provider driver")
Reviewed-by: Abel Vesa <abel.vesa@...aro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@...aro.org>
Signed-off-by: Johan Hovold <johan+linaro@...nel.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;
 }
-- 
2.39.2