Re: [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false

[Guenter Roeck <linux@roeck-us.net>]

Alexander,

On 4/8/25 19:11, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
> head:   d6b1492c9c2e7f2659b63a165ea45ab556c0df0c
> commit: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c [13/13] hwmon: (gpio-fan) Add regulator support
> config: riscv-randconfig-001-20250409 (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/config)
> compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 92c93f5286b9ff33f27ff694d2dc33da1c07afdd)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202504091047.biuX8Kl2-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>>> drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
>       250 |         if (val == 0)
>           |             ^~~~~~~~
>     drivers/hwmon/gpio-fan.c:255:9: note: uninitialized use occurs here
>       255 |         return ret ? ret : count;
>           |                ^~~
>     drivers/hwmon/gpio-fan.c:250:2: note: remove the 'if' if its condition is always true
>       250 |         if (val == 0)
>           |         ^~~~~~~~~~~~~
>       251 |                 ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
>     drivers/hwmon/gpio-fan.c:237:9: note: initialize the variable 'ret' to silence this warning
>       237 |         int ret;
>           |                ^
>           |                 = 0
>     1 warning generated.
> 

I dropped the patch from linux-next. Please fix and make sure there are no
such problems before resubmitting.

Thanks,
Guenter
> 
> vim +250 drivers/hwmon/gpio-fan.c
> 
> d6fe1360f42e86 Simon Guinot       2010-10-22  230
> c490c63e9505a3 Julia Lawall       2016-12-22  231  static ssize_t pwm1_enable_store(struct device *dev,
> c490c63e9505a3 Julia Lawall       2016-12-22  232  				 struct device_attribute *attr,
> d6fe1360f42e86 Simon Guinot       2010-10-22  233  				 const char *buf, size_t count)
> d6fe1360f42e86 Simon Guinot       2010-10-22  234  {
> d6fe1360f42e86 Simon Guinot       2010-10-22  235  	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
> d6fe1360f42e86 Simon Guinot       2010-10-22  236  	unsigned long val;
> d6b1492c9c2e7f Alexander Stein    2025-04-08  237  	int ret;
> d6fe1360f42e86 Simon Guinot       2010-10-22  238
> 179c4fdb565dd2 Frans Meulenbroeks 2012-01-04  239  	if (kstrtoul(buf, 10, &val) || val > 1)
> d6fe1360f42e86 Simon Guinot       2010-10-22  240  		return -EINVAL;
> d6fe1360f42e86 Simon Guinot       2010-10-22  241
> d6fe1360f42e86 Simon Guinot       2010-10-22  242  	if (fan_data->pwm_enable == val)
> d6fe1360f42e86 Simon Guinot       2010-10-22  243  		return count;
> d6fe1360f42e86 Simon Guinot       2010-10-22  244
> d6fe1360f42e86 Simon Guinot       2010-10-22  245  	mutex_lock(&fan_data->lock);
> d6fe1360f42e86 Simon Guinot       2010-10-22  246
> d6fe1360f42e86 Simon Guinot       2010-10-22  247  	fan_data->pwm_enable = val;
> d6fe1360f42e86 Simon Guinot       2010-10-22  248
> d6fe1360f42e86 Simon Guinot       2010-10-22  249  	/* Disable manual control mode: set fan at full speed. */
> d6fe1360f42e86 Simon Guinot       2010-10-22 @250  	if (val == 0)
> d6b1492c9c2e7f Alexander Stein    2025-04-08  251  		ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> d6fe1360f42e86 Simon Guinot       2010-10-22  252
> d6fe1360f42e86 Simon Guinot       2010-10-22  253  	mutex_unlock(&fan_data->lock);
> d6fe1360f42e86 Simon Guinot       2010-10-22  254
> d6b1492c9c2e7f Alexander Stein    2025-04-08  255  	return ret ? ret : count;
> d6fe1360f42e86 Simon Guinot       2010-10-22  256  }
> d6fe1360f42e86 Simon Guinot       2010-10-22  257
> 
> :::::: The code at line 250 was first introduced by commit
> :::::: d6fe1360f42e86262153927986dea6502daff703 hwmon: add generic GPIO fan driver
> 
> :::::: TO: Simon Guinot <sguinot@lacie.com>
> :::::: CC: Guenter Roeck <guenter.roeck@ericsson.com>
>