Re: [PATCH 1/2] target: Move IO path stats to per cpu

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

Hi Mike,

kernel test robot noticed the following build warnings:

[auto build test WARNING on mkp-scsi/for-next]
[also build test WARNING on linus/master v6.15-rc2 next-20250414]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mike-Christie/target-Move-IO-path-stats-to-per-cpu/20250414-113809
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next
patch link:    https://lore.kernel.org/r/20250413040500.20954-2-michael.christie%40oracle.com
patch subject: [PATCH 1/2] target: Move IO path stats to per cpu
config: i386-buildonly-randconfig-003-20250415 (https://download.01.org/0day-ci/archive/20250415/202504151524.Ar21ia6A-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250415/202504151524.Ar21ia6A-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/202504151524.Ar21ia6A-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/target/target_core_stat.c:289:3: warning: variable 'cmds' is uninitialized when used here [-Wuninitialized]
     289 |                 cmds += stats->total_cmds;
         |                 ^~~~
   drivers/target/target_core_stat.c:285:10: note: initialize the variable 'cmds' to silence this warning
     285 |         u32 cmds;
         |                 ^
         |                  = 0
>> drivers/target/target_core_stat.c:306:3: warning: variable 'bytes' is uninitialized when used here [-Wuninitialized]
     306 |                 bytes += stats->read_bytes;
         |                 ^~~~~
   drivers/target/target_core_stat.c:302:11: note: initialize the variable 'bytes' to silence this warning
     302 |         u32 bytes;
         |                  ^
         |                   = 0
   drivers/target/target_core_stat.c:323:3: warning: variable 'bytes' is uninitialized when used here [-Wuninitialized]
     323 |                 bytes += stats->write_bytes;
         |                 ^~~~~
   drivers/target/target_core_stat.c:319:11: note: initialize the variable 'bytes' to silence this warning
     319 |         u32 bytes;
         |                  ^
         |                   = 0
   drivers/target/target_core_stat.c:1058:3: warning: variable 'cmds' is uninitialized when used here [-Wuninitialized]
    1058 |                 cmds += stats->total_cmds;
         |                 ^~~~
   drivers/target/target_core_stat.c:1047:10: note: initialize the variable 'cmds' to silence this warning
    1047 |         u32 cmds;
         |                 ^
         |                  = 0
   drivers/target/target_core_stat.c:1087:3: warning: variable 'bytes' is uninitialized when used here [-Wuninitialized]
    1087 |                 bytes += stats->read_bytes;
         |                 ^~~~~
   drivers/target/target_core_stat.c:1076:11: note: initialize the variable 'bytes' to silence this warning
    1076 |         u32 bytes;
         |                  ^
         |                   = 0
   drivers/target/target_core_stat.c:1116:3: warning: variable 'bytes' is uninitialized when used here [-Wuninitialized]
    1116 |                 bytes += stats->write_bytes;
         |                 ^~~~~
   drivers/target/target_core_stat.c:1105:11: note: initialize the variable 'bytes' to silence this warning
    1105 |         u32 bytes;
         |                  ^
         |                   = 0
   6 warnings generated.


vim +/cmds +289 drivers/target/target_core_stat.c

   278	
   279	static ssize_t target_stat_lu_num_cmds_show(struct config_item *item,
   280			char *page)
   281	{
   282		struct se_device *dev = to_stat_lu_dev(item);
   283		struct se_dev_io_stats *stats;
   284		unsigned int cpu;
   285		u32 cmds;
   286	
   287		for_each_possible_cpu(cpu) {
   288			stats = per_cpu_ptr(dev->stats, cpu);
 > 289			cmds += stats->total_cmds;
   290		}
   291	
   292		/* scsiLuNumCommands */
   293		return snprintf(page, PAGE_SIZE, "%u\n", cmds);
   294	}
   295	
   296	static ssize_t target_stat_lu_read_mbytes_show(struct config_item *item,
   297			char *page)
   298	{
   299		struct se_device *dev = to_stat_lu_dev(item);
   300		struct se_dev_io_stats *stats;
   301		unsigned int cpu;
   302		u32 bytes;
   303	
   304		for_each_possible_cpu(cpu) {
   305			stats = per_cpu_ptr(dev->stats, cpu);
 > 306			bytes += stats->read_bytes;
   307		}
   308	
   309		/* scsiLuReadMegaBytes */
   310		return snprintf(page, PAGE_SIZE, "%u\n", bytes >> 20);
   311	}
   312	

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