linux-kernel - [PATCH 2/2] cpufreq: qcom-nvmem: eliminate uses of of_node

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Message-Id: <20240523-qcom-cpufreq-nvmem_memleak-v1-2-e57795c7afa7@gmail.com>
Date: Thu, 23 May 2024 23:25:00 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Ilia Lin <ilia.lin@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
 Viresh Kumar <viresh.kumar@...aro.org>
Cc: linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH 2/2] cpufreq: qcom-nvmem: eliminate uses of of_node_put()

Make use of the __free() macro to automate memory deallocation when
the existing device nodes get out of scope, removing the need for
of_node_put() and therefore increasing code safety if more error paths
are added to the driver, which could miss the required of_node_put()
as it already occurred with commit '57f2f8b4aa0c ("cpufreq: qcom:
Refactor the driver to make it easier to extend")'.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
 drivers/cpufreq/qcom-cpufreq-nvmem.c | 25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-nvmem.c b/drivers/cpufreq/qcom-cpufreq-nvmem.c
index 5004e1dbc752..716066423b92 100644
--- a/drivers/cpufreq/qcom-cpufreq-nvmem.c
+++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c
@@ -455,7 +455,6 @@ static int qcom_cpufreq_probe(struct platform_device *pdev)
 {
 	struct qcom_cpufreq_drv *drv;
 	struct nvmem_cell *speedbin_nvmem;
-	struct device_node *np;
 	struct device *cpu_dev;
 	char pvs_name_buffer[] = "speedXX-pvsXX-vXX";
 	char *pvs_name = pvs_name_buffer;
@@ -467,49 +466,40 @@ static int qcom_cpufreq_probe(struct platform_device *pdev)
 	if (!cpu_dev)
 		return -ENODEV;
 
-	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+	struct device_node *np __free(device_node) =
+		dev_pm_opp_of_get_opp_desc_node(cpu_dev);
 	if (!np)
 		return -ENOENT;
 
 	ret = of_device_is_compatible(np, "operating-points-v2-kryo-cpu") ||
 	      of_device_is_compatible(np, "operating-points-v2-krait-cpu");
-	if (!ret) {
-		of_node_put(np);
+	if (!ret)
 		return -ENOENT;
-	}
 
 	drv = devm_kzalloc(&pdev->dev, struct_size(drv, cpus, num_possible_cpus()),
 		           GFP_KERNEL);
-	if (!drv) {
-		of_node_put(np);
+	if (!drv)
 		return -ENOMEM;
-	}
 
 	match = pdev->dev.platform_data;
 	drv->data = match->data;
-	if (!drv->data) {
-		of_node_put(np);
+	if (!drv->data)
 		return -ENODEV;
-	}
 
 	if (drv->data->get_version) {
 		speedbin_nvmem = of_nvmem_cell_get(np, NULL);
-		if (IS_ERR(speedbin_nvmem)) {
-			of_node_put(np);
+		if (IS_ERR(speedbin_nvmem))
 			return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem),
 					     "Could not get nvmem cell\n");
-		}
 
 		ret = drv->data->get_version(cpu_dev,
 							speedbin_nvmem, &pvs_name, drv);
 		if (ret) {
-			of_node_put(np);
 			nvmem_cell_put(speedbin_nvmem);
 			return ret;
 		}
 		nvmem_cell_put(speedbin_nvmem);
 	}
-	of_node_put(np);
 
 	for_each_possible_cpu(cpu) {
 		struct device **virt_devs = NULL;
@@ -645,7 +635,7 @@ MODULE_DEVICE_TABLE(of, qcom_cpufreq_match_list);
  */
 static int __init qcom_cpufreq_init(void)
 {
-	struct device_node *np = of_find_node_by_path("/");
+	struct device_node *np __free(device_node) = of_find_node_by_path("/");
 	const struct of_device_id *match;
 	int ret;
 
@@ -653,7 +643,6 @@ static int __init qcom_cpufreq_init(void)
 		return -ENODEV;
 
 	match = of_match_node(qcom_cpufreq_match_list, np);
-	of_node_put(np);
 	if (!match)
 		return -ENODEV;
 

-- 
2.40.1