linux-kernel - [PATCH 2/2] hwmon: chipcap2: fix return path in cc2_request_alarm

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Date: Wed, 07 Feb 2024 22:17:09 +0100
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>, 
 Dan Carpenter <dan.carpenter@...aro.org>
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH 2/2] hwmon: chipcap2: fix return path in
 cc2_request_alarm_irqs()

The return path can be improved by returning upon first failure. The
current implementation would try to register the second interrupt even
if the first one failed, which is unnecessary.

Moreover, if no irqs are available, the return value should be zero
(the driver supports the use case with no interrupts). Currently the
initial value is unassigned and that may lead to returning an unknown
value if stack variables are not automatically set to zero and no irqs
were provided.

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Closes: https://lore.kernel.org/linux-hwmon/294e4634-89d4-415e-a723-b208d8770d7c@gmail.com/T/#t
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
 drivers/hwmon/chipcap2.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c
index 3b604fc5d8ae..6ccceae21f70 100644
--- a/drivers/hwmon/chipcap2.c
+++ b/drivers/hwmon/chipcap2.c
@@ -670,7 +670,7 @@ static int cc2_request_ready_irq(struct cc2_data *data, struct device *dev)
 
 static int cc2_request_alarm_irqs(struct cc2_data *data, struct device *dev)
 {
-	int ret;
+	int ret = 0;
 
 	data->irq_low = fwnode_irq_get_byname(dev_fwnode(dev), "low");
 	if (data->irq_low > 0) {
@@ -679,8 +679,10 @@ static int cc2_request_alarm_irqs(struct cc2_data *data, struct device *dev)
 						IRQF_ONESHOT |
 						IRQF_TRIGGER_RISING,
 						dev_name(dev), data);
-		if (!ret)
-			data->rh_alarm.low_alarm_visible = true;
+		if (ret)
+			return ret;
+
+		data->rh_alarm.low_alarm_visible = true;
 	}
 
 	data->irq_high = fwnode_irq_get_byname(dev_fwnode(dev), "high");
@@ -690,8 +692,10 @@ static int cc2_request_alarm_irqs(struct cc2_data *data, struct device *dev)
 						IRQF_ONESHOT |
 						IRQF_TRIGGER_RISING,
 						dev_name(dev), data);
-		if (!ret)
-			data->rh_alarm.high_alarm_visible = true;
+		if (ret)
+			return ret;
+
+		data->rh_alarm.high_alarm_visible = true;
 	}
 
 	return ret;

-- 
2.40.1