fs/ext4/fast_commit.c:1753:27: warning: unused function 'tag2str'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   b65054597872ce3aefbc6a666385eabdf9e288da
commit: 8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2 ext4: fast commit recovery path
date:   6 weeks ago
config: mips-randconfig-r023-20201201 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project ac40a2d8f16b8a8c68fc811d67f647740e965cb8)
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
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 8016e29f4362e285f0f7e38fadc61a5b7bdfdfa2
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> fs/ext4/fast_commit.c:1753:27: warning: unused function 'tag2str'
   static inline const char tag)
   ^
   fatal error: error in backend: Nested variants found in inline asm string: ' .set push
   .set mips64r2
   .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/bitops.h", .line = 133, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif
   1: ll $0, $1
   and $0, $2
   sc $0, $1
   beqz $0, 1b
   .set pop
   '
   clang-12: error: clang frontend command failed with exit code 70 (use -v to see invocation)
   clang version 12.0.0 (git://gitmirror/llvm_project ac40a2d8f16b8a8c68fc811d67f647740e965cb8)
   Target: mips-unknown-linux-gnu
   Thread model: posix
   InstalledDir: /opt/cross/clang-ac40a2d8f1/bin
   clang-12: note: diagnostic msg:
   Makefile arch fs include kernel scripts source usr

vim +/tag2str +1753 fs/ext4/fast_commit.c

  1752	
> 1753	static inline const char *tag2str(u16 tag)
  1754	{
  1755		switch (tag) {
  1756		case EXT4_FC_TAG_LINK:
  1757			return "TAG_ADD_ENTRY";
  1758		case EXT4_FC_TAG_UNLINK:
  1759			return "TAG_DEL_ENTRY";
  1760		case EXT4_FC_TAG_ADD_RANGE:
  1761			return "TAG_ADD_RANGE";
  1762		case EXT4_FC_TAG_CREAT:
  1763			return "TAG_CREAT_DENTRY";
  1764		case EXT4_FC_TAG_DEL_RANGE:
  1765			return "TAG_DEL_RANGE";
  1766		case EXT4_FC_TAG_INODE:
  1767			return "TAG_INODE";
  1768		case EXT4_FC_TAG_PAD:
  1769			return "TAG_PAD";
  1770		case EXT4_FC_TAG_TAIL:
  1771			return "TAG_TAIL";
  1772		case EXT4_FC_TAG_HEAD:
  1773			return "TAG_HEAD";
  1774		default:
  1775			return "TAG_ERROR";
  1776		}
  1777	}
  1778	

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

Attachment: .config.gz
Description: application/gzip