Re: [PATCH v2 13/23] counter: Provide alternative counter registration functions

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

Hi "Uwe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on a7904a538933c525096ca2ccde1e60d0ee62c08e]

url:    https://github.com/0day-ci/linux/commits/Uwe-Kleine-K-nig/counter-cleanups-and-device-lifetime-fixes/20211227-174815
base:   a7904a538933c525096ca2ccde1e60d0ee62c08e
config: i386-randconfig-r006-20211227 (https://download.01.org/0day-ci/archive/20211227/202112272054.WsrEZBF1-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 511726c64d3b6cca66f7c54d457d586aa3129f67)
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
        # https://github.com/0day-ci/linux/commit/250e0e3d91caea9f7c61652a7a9a8c006b2464be
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Uwe-Kleine-K-nig/counter-cleanups-and-device-lifetime-fixes/20211227-174815
        git checkout 250e0e3d91caea9f7c61652a7a9a8c006b2464be
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/counter/

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-core.c:175:41: warning: variable 'id' is uninitialized when used here [-Wuninitialized]
           dev->devt = MKDEV(MAJOR(counter_devt), id);
                                                  ^~
   include/linux/kdev_t.h:12:46: note: expanded from macro 'MKDEV'
   #define MKDEV(ma,mi)    (((ma) << MINORBITS) | (mi))
                                                   ^~
   drivers/counter/counter-core.c:149:8: note: initialize the variable 'id' to silence this warning
           int id, err;
                 ^
                  = 0
   1 warning generated.


vim +/id +175 drivers/counter/counter-core.c

   134	
   135	/**
   136	 * counter_alloc - allocate a counter_device
   137	 * @sizeof_priv: size of the driver private data
   138	 *
   139	 * This is part one of counter registration. The structure is allocated
   140	 * dynamically to ensure the right lifetime for the embedded struct device.
   141	 *
   142	 * If this succeeds, call counter_put() to get rid of the counter_device again.
   143	 */
   144	struct counter_device *counter_alloc(size_t sizeof_priv)
   145	{
   146		struct counter_device_allochelper *ch;
   147		struct counter_device *counter;
   148		struct device *dev;
   149		int id, err;
   150	
   151		ch = kzalloc(sizeof(*ch) + sizeof_priv, GFP_KERNEL);
   152		if (!ch) {
   153			err = -ENOMEM;
   154			goto err_alloc_ch;
   155		}
   156	
   157		counter = &ch->counter;
   158		dev = &counter->dev;
   159	
   160		/* Acquire unique ID */
   161		err = ida_alloc(&counter_ida, GFP_KERNEL);
   162		if (err < 0) {
   163			goto err_ida_alloc;
   164		}
   165		dev->id = err;
   166	
   167		err = counter_chrdev_add(counter);
   168		if (err < 0)
   169			goto err_chrdev_add;
   170	
   171		device_initialize(dev);
   172		/* Configure device structure for Counter */
   173		dev->type = &counter_device_type;
   174		dev->bus = &counter_bus_type;
 > 175		dev->devt = MKDEV(MAJOR(counter_devt), id);
   176	
   177		mutex_init(&counter->ops_exist_lock);
   178	
   179		return counter;
   180	
   181	err_chrdev_add:
   182	
   183		ida_free(&counter_ida, dev->id);
   184	err_ida_alloc:
   185	
   186		kfree(ch);
   187	err_alloc_ch:
   188	
   189		return ERR_PTR(err);
   190	}
   191	EXPORT_SYMBOL_GPL(counter_alloc);
   192	

---
0-DAY CI Kernel Test Service, Intel Corporation
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