Re: [PATCH RFC leds + net-next 2/3] leds: trigger: return error value if .activate() failed

[kernel test robot <lkp@intel.com>]

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Hi "Marek,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Marek-Beh-n/Add-support-for-LEDs-on-Marvell-PHYs/20200717-012010
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 59632b220f2d61df274ed3a14a204e941051fdad
config: powerpc-randconfig-r005-20200716 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project ed6b578040a85977026c93bf4188f996148f3218)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/leds/led-triggers.c:52:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (sysfs_streq(buf, "none")) {
               ^~~~~~~~~~~~~~~~~~~~~~~~
   drivers/leds/led-triggers.c:74:9: note: uninitialized use occurs here
           return ret < 0 ? ret : count;
                  ^~~
   drivers/leds/led-triggers.c:52:2: note: remove the 'if' if its condition is always false
           if (sysfs_streq(buf, "none")) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/leds/led-triggers.c:43:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.

vim +52 drivers/leds/led-triggers.c

abf0e9916c9400 Marek Behún      2020-07-16  35  
11f70002213774 Akinobu Mita     2019-09-29  36  ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
11f70002213774 Akinobu Mita     2019-09-29  37  			  struct bin_attribute *bin_attr, char *buf,
11f70002213774 Akinobu Mita     2019-09-29  38  			  loff_t pos, size_t count)
c3bc9956ec52fb Richard Purdie   2006-03-31  39  {
11f70002213774 Akinobu Mita     2019-09-29  40  	struct device *dev = kobj_to_dev(kobj);
f8a7c6fe14f556 Richard Purdie   2007-07-08  41  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
c3bc9956ec52fb Richard Purdie   2006-03-31  42  	struct led_trigger *trig;
979669942e8602 Marek Behún      2020-07-16  43  	int ret;
acd899e4f3066b Jacek Anaszewski 2014-09-22  44  
acd899e4f3066b Jacek Anaszewski 2014-09-22  45  	mutex_lock(&led_cdev->led_access);
acd899e4f3066b Jacek Anaszewski 2014-09-22  46  
acd899e4f3066b Jacek Anaszewski 2014-09-22  47  	if (led_sysfs_is_disabled(led_cdev)) {
acd899e4f3066b Jacek Anaszewski 2014-09-22  48  		ret = -EBUSY;
acd899e4f3066b Jacek Anaszewski 2014-09-22  49  		goto unlock;
acd899e4f3066b Jacek Anaszewski 2014-09-22  50  	}
c3bc9956ec52fb Richard Purdie   2006-03-31  51  
7296c33ed12ef1 Heiner Kallweit  2016-03-08 @52  	if (sysfs_streq(buf, "none")) {
0013b23d66a276 Németh Márton    2008-03-09  53  		led_trigger_remove(led_cdev);
acd899e4f3066b Jacek Anaszewski 2014-09-22  54  		goto unlock;
c3bc9956ec52fb Richard Purdie   2006-03-31  55  	}
c3bc9956ec52fb Richard Purdie   2006-03-31  56  
dc47206e552c08 Richard Purdie   2007-11-10  57  	down_read(&triggers_list_lock);
c3bc9956ec52fb Richard Purdie   2006-03-31  58  	list_for_each_entry(trig, &trigger_list, next_trig) {
abf0e9916c9400 Marek Behún      2020-07-16  59  		if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
dc47206e552c08 Richard Purdie   2007-11-10  60  			down_write(&led_cdev->trigger_lock);
979669942e8602 Marek Behún      2020-07-16  61  			ret = led_trigger_set(led_cdev, trig);
dc47206e552c08 Richard Purdie   2007-11-10  62  			up_write(&led_cdev->trigger_lock);
c3bc9956ec52fb Richard Purdie   2006-03-31  63  
dc47206e552c08 Richard Purdie   2007-11-10  64  			up_read(&triggers_list_lock);
acd899e4f3066b Jacek Anaszewski 2014-09-22  65  			goto unlock;
c3bc9956ec52fb Richard Purdie   2006-03-31  66  		}
c3bc9956ec52fb Richard Purdie   2006-03-31  67  	}
a3eac76cdf7225 Heiner Kallweit  2016-07-01  68  	/* we come here only if buf matches no trigger */
a3eac76cdf7225 Heiner Kallweit  2016-07-01  69  	ret = -EINVAL;
dc47206e552c08 Richard Purdie   2007-11-10  70  	up_read(&triggers_list_lock);
c3bc9956ec52fb Richard Purdie   2006-03-31  71  
acd899e4f3066b Jacek Anaszewski 2014-09-22  72  unlock:
acd899e4f3066b Jacek Anaszewski 2014-09-22  73  	mutex_unlock(&led_cdev->led_access);
979669942e8602 Marek Behún      2020-07-16  74  	return ret < 0 ? ret : count;
c3bc9956ec52fb Richard Purdie   2006-03-31  75  }
11f70002213774 Akinobu Mita     2019-09-29  76  EXPORT_SYMBOL_GPL(led_trigger_write);
c3bc9956ec52fb Richard Purdie   2006-03-31  77  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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