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From:   Niklas Cassel <niklas.cassel@linaro.org>
To:     broonie@kernel.org, Liam Girdwood <lgirdwood@gmail.com>
Cc:     linux-arm-msm@vger.kernel.org, johan@kernel.org,
        Niklas Cassel <niklas.cassel@linaro.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/4] regulator: qcom_spmi: Fix warning Bad of_node_put()
Date:   Mon, 16 Jul 2018 15:32:51 +0200
Message-Id: <20180716133255.1506-2-niklas.cassel@linaro.org>
In-Reply-To: <20180716133255.1506-1-niklas.cassel@linaro.org>
References: <20180716133255.1506-1-niklas.cassel@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

For of_find_node_by_name(), you typically pass what the previous call
returned. Therefore, of_find_node_by_name() increases the refcount of
the returned node, and decreases the refcount of the node passed as the
first argument.

of_find_node_by_name() is incorrectly used, and produces a warning.
Fix the warning by using the more suitable function
of_get_child_by_name().

Also add a missing of_node_put() for the returned value, since this was
previously being leaked.

OF: ERROR: Bad of_node_put() on /soc/qcom,spmi@400f000/pmic@3/regulators
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W         4.18.0-rc4-00223-gefd7b360b70e #12
Hardware name: Qualcomm Technologies, Inc. DB820c (DT)
Call trace:
 dump_backtrace+0x0/0x1a8
 show_stack+0x14/0x20
 dump_stack+0x90/0xb4
 of_node_release+0x74/0x78
 kobject_put+0x90/0x1f0
 of_node_put+0x14/0x20
 of_find_node_by_name+0x80/0xd8
 qcom_spmi_regulator_probe+0x30c/0x508

Fixes: 0caecaa87202 ("regulator: qcom_spmi: Add support for SAW")
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
---
Changes since v1:
-Use of_get_child_by_name() instead of of_find_node_by_name().

 drivers/regulator/qcom_spmi-regulator.c | 32 +++++++++++++++----------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/regulator/qcom_spmi-regulator.c b/drivers/regulator/qcom_spmi-regulator.c
index 9817f1a75342..4cc14c65d86b 100644
--- a/drivers/regulator/qcom_spmi-regulator.c
+++ b/drivers/regulator/qcom_spmi-regulator.c
@@ -1752,7 +1752,8 @@ static int qcom_spmi_regulator_probe(struct platform_device *pdev)
 	const char *name;
 	struct device *dev = &pdev->dev;
 	struct device_node *node = pdev->dev.of_node;
-	struct device_node *syscon;
+	struct device_node *syscon, *reg_node;
+	struct property *reg_prop;
 	int ret, lenp;
 	struct list_head *vreg_list;
 
@@ -1780,10 +1781,13 @@ static int qcom_spmi_regulator_probe(struct platform_device *pdev)
 
 	for (reg = match->data; reg->name; reg++) {
 
-		if (saw_regmap && \
-		    of_find_property(of_find_node_by_name(node, reg->name), \
-				     "qcom,saw-slave", &lenp)) {
-			continue;
+		if (saw_regmap) {
+			reg_node = of_get_child_by_name(node, reg->name);
+			reg_prop = of_find_property(reg_node, "qcom,saw-slave",
+						    &lenp);
+			of_node_put(reg_node);
+			if (reg_prop)
+				continue;
 		}
 
 		vreg = devm_kzalloc(dev, sizeof(*vreg), GFP_KERNEL);
@@ -1816,13 +1820,17 @@ static int qcom_spmi_regulator_probe(struct platform_device *pdev)
 		if (ret)
 			continue;
 
-		if (saw_regmap && \
-		    of_find_property(of_find_node_by_name(node, reg->name), \
-				     "qcom,saw-leader", &lenp)) {
-			spmi_saw_ops = *(vreg->desc.ops);
-			spmi_saw_ops.set_voltage_sel = \
-				spmi_regulator_saw_set_voltage;
-			vreg->desc.ops = &spmi_saw_ops;
+		if (saw_regmap) {
+			reg_node = of_get_child_by_name(node, reg->name);
+			reg_prop = of_find_property(reg_node, "qcom,saw-leader",
+						    &lenp);
+			of_node_put(reg_node);
+			if (reg_prop) {
+				spmi_saw_ops = *(vreg->desc.ops);
+				spmi_saw_ops.set_voltage_sel =
+					spmi_regulator_saw_set_voltage;
+				vreg->desc.ops = &spmi_saw_ops;
+			}
 		}
 
 		config.dev = dev;
-- 
2.17.1