Re: [PATCH v6 1/5] counter: Internalize sysfs interface code

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

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Hi William,

I love your patch! Perhaps something to improve:

[auto build test WARNING on stm32/stm32-next]
[also build test WARNING on linux/master linus/master v5.10-rc4 next-20201120]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/William-Breathitt-Gray/Introduce-the-Counter-character-device-interface/20201123-043634
base:   https://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32.git stm32-next
config: x86_64-randconfig-a011-20201122 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 3324fd8a7b1ab011513017ed8fd81e06928526d5)
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 x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/1bc8c3bb021f3736c23d97f1a965935821f0ac5a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review William-Breathitt-Gray/Introduce-the-Counter-character-device-interface/20201123-043634
        git checkout 1bc8c3bb021f3736c23d97f1a965935821f0ac5a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

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/counter/counter-sysfs.c:180:7: warning: variable 'err' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
                   if (idx < 0)
                       ^~~~~~~
   drivers/counter/counter-sysfs.c:193:6: note: uninitialized use occurs here
           if (err)
               ^~~
   drivers/counter/counter-sysfs.c:180:3: note: remove the 'if' if its condition is always true
                   if (idx < 0)
                   ^~~~~~~~~~~~
   drivers/counter/counter-sysfs.c:158:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   1 warning generated.

vim +180 drivers/counter/counter-sysfs.c

   148	
   149	static ssize_t counter_comp_u8_store(struct device *dev,
   150					     struct device_attribute *attr,
   151					     const char *buf, size_t len)
   152	{
   153		const struct counter_attribute *const a = to_counter_attribute(attr);
   154		struct counter_device *const counter = dev_get_drvdata(dev);
   155		struct counter_count *const count = a->parent;
   156		struct counter_synapse *const synapse = a->comp.priv;
   157		const struct counter_available *const avail = a->comp.priv;
   158		int err;
   159		bool bool_data;
   160		int idx;
   161		u8 data;
   162	
   163		switch (a->comp.type) {
   164		case COUNTER_COMP_BOOL:
   165			err = kstrtobool(buf, &bool_data);
   166			data = bool_data;
   167			break;
   168		case COUNTER_COMP_FUNCTION:
   169			err = find_in_string_array(&data, count->functions_list,
   170						   count->num_functions, buf,
   171						   counter_function_str);
   172			break;
   173		case COUNTER_COMP_SYNAPSE_ACTION:
   174			err = find_in_string_array(&data, synapse->actions_list,
   175						   synapse->num_actions, buf,
   176						   counter_synapse_action_str);
   177			break;
   178		case COUNTER_COMP_ENUM:
   179			idx = __sysfs_match_string(avail->strs, avail->num_items, buf);
 > 180			if (idx < 0)
   181				return idx;
   182			data = idx;
   183			break;
   184		case COUNTER_COMP_COUNT_MODE:
   185			err = find_in_string_array(&data, avail->enums,
   186						   avail->num_items, buf,
   187						   counter_count_mode_str);
   188			break;
   189		default:
   190			err = kstrtou8(buf, 0, &data);
   191			break;
   192		}
   193		if (err)
   194			return err;
   195	
   196		switch (a->scope) {
   197		case COUNTER_SCOPE_DEVICE:
   198			err = a->comp.device_u8_write(counter, data);
   199			break;
   200		case COUNTER_SCOPE_SIGNAL:
   201			err = a->comp.signal_u8_write(counter, a->parent, data);
   202			break;
   203		case COUNTER_SCOPE_COUNT:
   204			if (a->comp.type == COUNTER_COMP_SYNAPSE_ACTION)
   205				err = a->comp.action_write(counter, count, synapse,
   206							   data);
   207			else
   208				err = a->comp.count_u8_write(counter, count, data);
   209			break;
   210		}
   211		if (err)
   212			return err;
   213	
   214		return len;
   215	}
   216	

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

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