linux-kernel - [PATCH v2] hwmon: (asus_wmi_sensors) Save a few bytes of memory

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Date:   Sat,  2 Jul 2022 08:05:54 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Ed Brindley <kernel@...davale.org>,
        Denis Pauk <pauk.denis@...il.com>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        linux-hwmon@...r.kernel.org
Subject: [PATCH v2] hwmon: (asus_wmi_sensors) Save a few bytes of memory

The first 'for' loop of asus_wmi_configure_sensor_setup() only computes
the number and type of sensors that exist in the system.

Here, the 'temp_sensor' structure is only used to store the data collected
by asus_wmi_sensor_info(). There is no point in using a devm_ variant for
this allocation. This wastes some memory for no good reason.

Use the stack instead.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
v1 -> v2: Use the stack instead of kmalloc/kfree to simplify even more the
          code (Guenter Roeck)
---
 drivers/hwmon/asus_wmi_sensors.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/hwmon/asus_wmi_sensors.c b/drivers/hwmon/asus_wmi_sensors.c
index 9e935e34c998..6e8a908171f0 100644
--- a/drivers/hwmon/asus_wmi_sensors.c
+++ b/drivers/hwmon/asus_wmi_sensors.c
@@ -514,22 +514,20 @@ static int asus_wmi_configure_sensor_setup(struct device *dev,
 	int i, idx;
 	int err;
 
-	temp_sensor = devm_kcalloc(dev, 1, sizeof(*temp_sensor), GFP_KERNEL);
-	if (!temp_sensor)
-		return -ENOMEM;
-
 	for (i = 0; i < sensor_data->wmi.sensor_count; i++) {
-		err = asus_wmi_sensor_info(i, temp_sensor);
+		struct asus_wmi_sensor_info sensor;
+
+		err = asus_wmi_sensor_info(i, &sensor);
 		if (err)
 			return err;
 
-		switch (temp_sensor->data_type) {
+		switch (sensor.data_type) {
 		case TEMPERATURE_C:
 		case VOLTAGE:
 		case CURRENT:
 		case FAN_RPM:
 		case WATER_FLOW:
-			type = asus_data_types[temp_sensor->data_type];
+			type = asus_data_types[sensor.data_type];
 			if (!nr_count[type])
 				nr_types++;
 			nr_count[type]++;
-- 
2.34.1