linux-kernel - [PATCH v2 3/3] hwmon: (ltc2992) Use fwnode_for_each_available_child_node

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Message-Id: <20240523-fwnode_for_each_available_child_node_scoped-v2-3-701f3a03f2fb@gmail.com>
Date: Thu, 23 May 2024 17:47:16 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, 
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
 Daniel Scally <djrscally@...il.com>, 
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Sakari Ailus <sakari.ailus@...ux.intel.com>, 
 Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>, 
 Antoniu Miclaus <antoniu.miclaus@...log.com>, 
 Jonathan Cameron <jic23@...nel.org>
Cc: linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-hwmon@...r.kernel.org, 
 Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH v2 3/3] hwmon: (ltc2992) Use
 fwnode_for_each_available_child_node_scoped()

The scoped version of the fwnode_for_each_available_child_node() macro
automates object recfount decrement, avoiding possible memory leaks
in new error paths inside the loop like it happened when
commit '10b029020487 ("hwmon: (ltc2992) Avoid division by zero")'
was added.

The new macro removes the need to manually call fwnode_handle_put() in
the existing error paths and in any future addition. It also removes the
need for the current child node declaration as well, as it is internally
declared.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
 drivers/hwmon/ltc2992.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/hwmon/ltc2992.c b/drivers/hwmon/ltc2992.c
index d4a93223cd3b..3feee400ecf8 100644
--- a/drivers/hwmon/ltc2992.c
+++ b/drivers/hwmon/ltc2992.c
@@ -855,32 +855,25 @@ static const struct regmap_config ltc2992_regmap_config = {
 static int ltc2992_parse_dt(struct ltc2992_state *st)
 {
 	struct fwnode_handle *fwnode;
-	struct fwnode_handle *child;
 	u32 addr;
 	u32 val;
 	int ret;

 	fwnode = dev_fwnode(&st->client->dev);

-	fwnode_for_each_available_child_node(fwnode, child) {
+	fwnode_for_each_available_child_node_scoped(fwnode, child) {
 		ret = fwnode_property_read_u32(child, "reg", &addr);
-		if (ret < 0) {
-			fwnode_handle_put(child);
+		if (ret < 0)
 			return ret;
-		}

-		if (addr > 1) {
-			fwnode_handle_put(child);
+		if (addr > 1)
 			return -EINVAL;
-		}

 		ret = fwnode_property_read_u32(child, "shunt-resistor-micro-ohms", &val);
 		if (!ret) {
-			if (!val) {
-				fwnode_handle_put(child);
+			if (!val)
 				return dev_err_probe(&st->client->dev, -EINVAL,
 						     "shunt resistor value cannot be zero\n");
-			}
 			st->r_sense_uohm[addr] = val;
 		}
 	}

-- 
2.40.1