From:   Johan Hovold <johan+linaro@kernel.org>
To:     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>,
        "Konrad Dybcio" <konrad.dybcio@linaro.org>,
        "Sylwester Nawrocki" <s.nawrocki@samsung.com>,
        =?UTF-8?q?Artur=20=C5=9Awigo=C5=84?= <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,
        Johan Hovold <johan+linaro@kernel.org>, stable@vger.kernel.org,
        Vinod Koul <vkoul@kernel.org>
Subject: [PATCH v2 12/23] interconnect: qcom: sm8450: fix registration race
Date:   Mon,  6 Mar 2023 08:56:40 +0100
Message-Id: <20230306075651.2449-13-johan+linaro@kernel.org>
In-Reply-To: <20230306075651.2449-1-johan+linaro@kernel.org>
References: <20230306075651.2449-1-johan+linaro@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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: fafc114a468e ("interconnect: qcom: Add SM8450 interconnect provider driver")
Cc: stable@vger.kernel.org      # 5.17
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/interconnect/qcom/sm8450.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/interconnect/qcom/sm8450.c b/drivers/interconnect/qcom/sm8450.c
index e3a12e3d6e06..c7a8bbf102a3 100644
--- a/drivers/interconnect/qcom/sm8450.c
+++ b/drivers/interconnect/qcom/sm8450.c
@@ -1876,9 +1876,10 @@ 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;
@@ -1887,12 +1888,6 @@ 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(&pdev->dev, "error adding interconnect provider\n");
-		return ret;
-	}
-
 	for (i = 0; i < qp->num_bcms; i++)
 		qcom_icc_bcm_init(qp->bcms[i], &pdev->dev);
 
@@ -1905,7 +1900,7 @@ 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;
@@ -1919,12 +1914,17 @@ 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;
 }
 
@@ -1932,8 +1932,8 @@ 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