Currently i8k_set_fan() clamps the fan speed before performing the
SMM call to ensure that the speed is not negative and not greater than
i8k_fan_max. This however is mostly unnecessary as the hwmon and
thermal interfaces alread ensure this. Only the legacy ioctl interface
does not ensure that the fan speed passed to i8k_set_fan() does meet
the above criteria.

Move the clamping out of i8k_set_fan() and into the legacy ioctl
handler to prepare for future changes.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/hwmon/dell-smm-hwmon.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 3f61b2d7935e..36576db09706 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/kconfig.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
@@ -446,7 +447,6 @@ static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed)
 	if (disallow_fan_support)
 		return -EINVAL;
 
-	speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
 	regs.ebx = fan | (speed << 8);
 
 	return dell_smm_call(data->ops, &regs);
@@ -637,6 +637,8 @@ static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
 			return -EFAULT;
 
+		speed = clamp_val(speed, 0, data->i8k_fan_max);
+
 		mutex_lock(&data->i8k_mutex);
 		err = i8k_set_fan(data, val, speed);
 		if (err < 0)
-- 
2.39.5

On Wed, Sep 17, 2025 at 08:10:34PM +0200, Armin Wolf wrote:
> Currently i8k_set_fan() clamps the fan speed before performing the
> SMM call to ensure that the speed is not negative and not greater than
> i8k_fan_max. This however is mostly unnecessary as the hwmon and
> thermal interfaces alread ensure this. Only the legacy ioctl interface
> does not ensure that the fan speed passed to i8k_set_fan() does meet
> the above criteria.
> 
> Move the clamping out of i8k_set_fan() and into the legacy ioctl
> handler to prepare for future changes.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Applied.

Guenter