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,
        Dmitry Osipenko <digetx@gmail.com>
Subject: [PATCH v2 18/23] memory: tegra124-emc: fix interconnect registration race
Date:   Mon,  6 Mar 2023 08:56:46 +0100
Message-Id: <20230306075651.2449-19-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: 380def2d4cf2 ("memory: tegra124: Support interconnect framework")
Cc: stable@vger.kernel.org      # 5.12
Cc: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/memory/tegra/tegra124-emc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c
index 85bc936c02f9..00ed2b6a0d1b 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -1351,15 +1351,13 @@ static int tegra_emc_interconnect_init(struct tegra_emc *emc)
 	emc->provider.aggregate = soc->icc_ops->aggregate;
 	emc->provider.xlate_extended = emc_of_icc_xlate_extended;
 
-	err = icc_provider_add(&emc->provider);
-	if (err)
-		goto err_msg;
+	icc_provider_init(&emc->provider);
 
 	/* create External Memory Controller node */
 	node = icc_node_create(TEGRA_ICC_EMC);
 	if (IS_ERR(node)) {
 		err = PTR_ERR(node);
-		goto del_provider;
+		goto err_msg;
 	}
 
 	node->name = "External Memory Controller";
@@ -1380,12 +1378,14 @@ static int tegra_emc_interconnect_init(struct tegra_emc *emc)
 	node->name = "External Memory (DRAM)";
 	icc_node_add(node, &emc->provider);
 
+	err = icc_provider_register(&emc->provider);
+	if (err)
+		goto remove_nodes;
+
 	return 0;
 
 remove_nodes:
 	icc_nodes_remove(&emc->provider);
-del_provider:
-	icc_provider_del(&emc->provider);
 err_msg:
 	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
 
-- 
2.39.2