Re: [RFC PATCH 2/5] tracing/hwlat: Implement the mode config option

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

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Hi Daniel,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on tip/perf/core]
[also build test WARNING on trace/for-next linux/master linus/master v5.12-rc6 next-20210408]
[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/Daniel-Bristot-de-Oliveira/hwlat-improvements-and-osnoise-tracer/20210408-221655
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git cface0326a6c2ae5c8f47bd466f07624b3e348a7
config: openrisc-randconfig-r013-20210408 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
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/a09dc6bb34fa0ac2596763b3a0285717799b57ce
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Daniel-Bristot-de-Oliveira/hwlat-improvements-and-osnoise-tracer/20210408-221655
        git checkout a09dc6bb34fa0ac2596763b3a0285717799b57ce
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=openrisc 

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 >>):

   kernel/trace/trace_hwlat.c: In function 'hwlat_mode_write':
>> kernel/trace/trace_hwlat.c:711:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
     711 |  int ret;
         |      ^~~


vim +/ret +711 kernel/trace/trace_hwlat.c

   691	
   692	/**
   693	 * hwlat_mode_write - Write function for "mode" entry
   694	 * @filp: The active open file structure
   695	 * @ubuf: The user buffer that contains the value to write
   696	 * @cnt: The maximum number of bytes to write to "file"
   697	 * @ppos: The current position in @file
   698	 *
   699	 * This function provides a write implementation for the "mode" interface
   700	 * to the hardware latency detector. hwlatd has different operation modes.
   701	 * The "none" sets the allowed cpumask for a single hwlatd thread at the
   702	 * startup and lets the scheduler handle the migration. The default mode is
   703	 * the "round-robin" one, in which a single hwlatd thread runs, migrating
   704	 * among the allowed CPUs in a round-robin fashion.
   705	 */
   706	static ssize_t hwlat_mode_write(struct file *filp, const char __user *ubuf,
   707					 size_t cnt, loff_t *ppos)
   708	{
   709		const char *mode;
   710		char buf[64];
 > 711		int ret;
   712		int i;
   713	
   714		if (hwlat_busy)
   715			return -EBUSY;
   716	
   717		if (cnt >= sizeof(buf))
   718			return -EINVAL;
   719	
   720		if (copy_from_user(buf, ubuf, cnt))
   721			return -EFAULT;
   722	
   723		buf[cnt] = 0;
   724	
   725		mode = strstrip(buf);
   726	
   727		ret = -EINVAL;
   728	
   729		for (i = 0; i < MODE_MAX; i++) {
   730			if (strcmp(mode, thread_mode_str[i]) == 0) {
   731				hwlat_data.thread_mode = i;
   732				ret = cnt;
   733			}
   734		}
   735	
   736		*ppos += cnt;
   737	
   738		return cnt;
   739	}
   740	

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

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