tree: git://git.samba.org/sfrench/cifs-2.6.git for-next head: bba805a46c91e7a8a1d04704e5409f890acf8b66 commit: bba805a46c91e7a8a1d04704e5409f890acf8b66 [1/1] cifs: rename fs/cifs directory to fs/smbfs config: x86_64-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): git remote add cifs git://git.samba.org/sfrench/cifs-2.6.git git fetch --no-tags cifs for-next git checkout bba805a46c91e7a8a1d04704e5409f890acf8b66 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): >> fs/smbfs/cifsroot.c:83:12: warning: no previous prototype for 'cifs_root_data' [-Wmissing-prototypes] 83 | int __init cifs_root_data(char **dev, char **opts) | ^~~~~~~~~~~~~~ vim +/cifs_root_data +83 fs/smbfs/cifsroot.c 8eecd1c2e5bc73 fs/cifs/cifsroot.c Paulo Alcantara (SUSE 2019-07-16 82) 8eecd1c2e5bc73 fs/cifs/cifsroot.c Paulo Alcantara (SUSE 2019-07-16 @83) int __init cifs_root_data(char **dev, char **opts) :::::: The code at line 83 was first introduced by commit :::::: 8eecd1c2e5bc73d33f3a544751305679dbf88eb4 cifs: Add support for root file systems :::::: TO: Paulo Alcantara (SUSE) <paulo(a)paulo.ac&gt; :::::: CC: Steve French <stfrench(a)microsoft.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org