Hi Theodore,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/perf/core]
[also build test ERROR on linus/master v5.5-rc3 next-20191220]
[cannot apply to tytso-fscrypt/master]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Theodore-Ts-o/memcg-fix-a-crash-in-wb_workfn-when-a-device-disappears/20191228-035221
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 1f676247f36a4bdea134de5e8bc5041db9678c4e
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

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

All error/warnings (new ones prefixed by >>):

   In file included from mm/fadvise.c:16:0:
   include/linux/backing-dev.h: In function 'bdi_dev_name':
>> include/linux/backing-dev.h:513:9: error: implicit declaration of function 'dev_name'; did you mean 'getname'? [-Werror=implicit-function-declaration]
     return dev_name(bdi->dev);
            ^~~~~~~~
            getname
>> include/linux/backing-dev.h:513:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
     return dev_name(bdi->dev);
            ^~~~~~~~~~~~~~~~~~
   In file included from include/linux/node.h:18:0,
                    from include/linux/cpu.h:17,
                    from include/linux/perf_event.h:50,
                    from include/linux/trace_events.h:10,
                    from include/trace/syscall.h:7,
                    from include/linux/syscalls.h:85,
                    from mm/fadvise.c:20:
   include/linux/device.h: At top level:
>> include/linux/device.h:1370:27: error: conflicting types for 'dev_name'
    static inline const char *dev_name(const struct device *dev)
                              ^~~~~~~~
   In file included from mm/fadvise.c:16:0:
   include/linux/backing-dev.h:513:9: note: previous implicit declaration of 'dev_name' was here
     return dev_name(bdi->dev);
            ^~~~~~~~
   cc1: some warnings being treated as errors
--
   In file included from fs/super.c:32:0:
   include/linux/backing-dev.h: In function 'bdi_dev_name':
>> include/linux/backing-dev.h:513:9: error: implicit declaration of function 'dev_name'; did you mean 'getname'? [-Werror=implicit-function-declaration]
     return dev_name(bdi->dev);
            ^~~~~~~~
            getname
>> include/linux/backing-dev.h:513:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
     return dev_name(bdi->dev);
            ^~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +513 include/linux/backing-dev.h

   508	
   509	static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
   510	{
   511		if (!bdi || !bdi->dev)
   512			return bdi_unknown_name;
 > 513		return dev_name(bdi->dev);
   514	}
   515	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
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