linux-kernel - [PATCH v4] powerpc:85xx: Add missing of_node_put() in sgy

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Message-Id: <20220617060827.4004795-1-windhl@126.com>
Date:   Fri, 17 Jun 2022 14:08:26 +0800
From:   Liang He <windhl@....com>
To:     oss@...error.net, mpe@...erman.id.au, benh@...nel.crashing.org,
        paulus@...ba.org
Cc:     windhl@....com, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4] powerpc:85xx: Add missing of_node_put() in sgy_cst1000

In gpio_halt_probe(), of_find_matching_node() will return a node
pointer with refcount incremented. We should use of_node_put() in
fail path or when it is not used anymore.

Signed-off-by: Liang He <windhl@....com>
---
 changelog:
 v4: reuse exist 'err' and use a simple code style, advised by CJ
 v3: use local 'child_node' advised by Michael.
 v2: use goto-label patch style advised by Christophe Leroy.
 v1: add of_node_put() before each exit.

 arch/powerpc/platforms/85xx/sgy_cts1000.c | 35 ++++++++++++++---------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/85xx/sgy_cts1000.c b/arch/powerpc/platforms/85xx/sgy_cts1000.c
index 98ae64075193..e4588943fe7e 100644
--- a/arch/powerpc/platforms/85xx/sgy_cts1000.c
+++ b/arch/powerpc/platforms/85xx/sgy_cts1000.c
@@ -71,6 +71,7 @@ static int gpio_halt_probe(struct platform_device *pdev)
 {
 	enum of_gpio_flags flags;
 	struct device_node *node = pdev->dev.of_node;
+	struct device_node *child_node;
 	int gpio, err, irq;
 	int trigger;
 
@@ -78,26 +79,29 @@ static int gpio_halt_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	/* If there's no matching child, this isn't really an error */
-	halt_node = of_find_matching_node(node, child_match);
-	if (!halt_node)
+	child_node = of_find_matching_node(node, child_match);
+	if (!child_node)
 		return 0;
 
 	/* Technically we could just read the first one, but punish
 	 * DT writers for invalid form. */
-	if (of_gpio_count(halt_node) != 1)
-		return -EINVAL;
+	if (of_gpio_count(child_node) != 1) {
+		err = -EINVAL;
+		goto err_put;
+	}
 
 	/* Get the gpio number relative to the dynamic base. */
-	gpio = of_get_gpio_flags(halt_node, 0, &flags);
-	if (!gpio_is_valid(gpio))
-		return -EINVAL;
+	gpio = of_get_gpio_flags(child_node, 0, &flags);
+	if (!gpio_is_valid(gpio)) {
+		err = -EINVAL;
+		gotot err_put;
+	}
 
 	err = gpio_request(gpio, "gpio-halt");
 	if (err) {
 		printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
 		       gpio);
-		halt_node = NULL;
-		return err;
+		goto err_put;
 	}
 
 	trigger = (flags == OF_GPIO_ACTIVE_LOW);
@@ -105,15 +109,14 @@ static int gpio_halt_probe(struct platform_device *pdev)
 	gpio_direction_output(gpio, !trigger);
 
 	/* Now get the IRQ which tells us when the power button is hit */
-	irq = irq_of_parse_and_map(halt_node, 0);
+	irq = irq_of_parse_and_map(child_node, 0);
 	err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
-			  IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
+			  IRQF_TRIGGER_FALLING, "gpio-halt", child_node);
 	if (err) {
 		printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
 		       "GPIO %d.\n", irq, gpio);
 		gpio_free(gpio);
-		halt_node = NULL;
-		return err;
+		goto err_put;
 	}
 
 	/* Register our halt function */
@@ -123,7 +126,12 @@ static int gpio_halt_probe(struct platform_device *pdev)
 	printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
 	       " irq).\n", gpio, trigger, irq);
 
+	halt_node = child_node;
 	return 0;
+
+err_put:
+	of_node_put(child_node);
+	return err;
 }
 
 static int gpio_halt_remove(struct platform_device *pdev)
@@ -139,6 +147,7 @@ static int gpio_halt_remove(struct platform_device *pdev)
 
 		gpio_free(gpio);
 
+		of_node_put(halt_node);
 		halt_node = NULL;
 	}
 
-- 
2.25.1