arch/mips/bmips/dma.c:7:6: warning: no previous prototype for function 'arch_sync_dma_for_cpu_all'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   79e06c4c4950be2abd8ca5d2428a8c915aa62c24
commit: d552ddeaab4a15a8dc157ac007833aa0b3706862 MIPS: bmips: Remove obsolete DMA mapping support
date:   5 days ago
config: mips-bmips_stb_defconfig (https://download.01.org/0day-ci/archive/20220117/202201170455.DlrxW9Pv-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c63a3175c2947e8c1a2d3bbe16a8586600705c54)
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=d552ddeaab4a15a8dc157ac007833aa0b3706862
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout d552ddeaab4a15a8dc157ac007833aa0b3706862
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash arch/mips/bmips/

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

All warnings (new ones prefixed by >>):

>> arch/mips/bmips/dma.c:7:6: warning: no previous prototype for function 'arch_sync_dma_for_cpu_all' [-Wmissing-prototypes]
   void arch_sync_dma_for_cpu_all(void)
        ^
   arch/mips/bmips/dma.c:7:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void arch_sync_dma_for_cpu_all(void)
   ^
   static 
   1 warning generated.


vim +/arch_sync_dma_for_cpu_all +7 arch/mips/bmips/dma.c

d666cd0246f78b arch/mips/bcm3384/dma.c Kevin Cernekee    2014-10-20  6  
56e35f9c5b87ec arch/mips/bmips/dma.c   Christoph Hellwig 2019-11-07 @7  void arch_sync_dma_for_cpu_all(void)

:::::: The code at line 7 was first introduced by commit
:::::: 56e35f9c5b87ec1ae93e483284e189c84388de16 dma-mapping: drop the dev argument to arch_sync_dma_for_*

:::::: TO: Christoph Hellwig <hch@xxxxxx>
:::::: CC: Christoph Hellwig <hch@xxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
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