[jolsa-perf:bpf/tracing_multi_5 2/10] include/linux/ftrace.h:557:5: warning: no previous prototype for function 'register_ftrace_direct_hash'

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/tracing_multi_5
head:   b288c6b15d20122d59ddf3bce2fb86afe6ed56c3
commit: c9910285c9bbb6b3afad3d1048ef11abf71bcdeb [2/10] ftrace: Add register_ftrace_direct_hash function
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20250620/202506201654.MhDdEOll-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250620/202506201654.MhDdEOll-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506201654.MhDdEOll-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from mm/filemap.c:25:
   In file included from include/linux/syscalls.h:94:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:10:
   In file included from include/linux/perf_event.h:43:
>> include/linux/ftrace.h:557:5: warning: no previous prototype for function 'register_ftrace_direct_hash' [-Wmissing-prototypes]
     557 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:557:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     557 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   1 warning generated.
--
   In file included from mm/shmem.c:77:
   In file included from include/linux/syscalls.h:94:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:10:
   In file included from include/linux/perf_event.h:43:
>> include/linux/ftrace.h:557:5: warning: no previous prototype for function 'register_ftrace_direct_hash' [-Wmissing-prototypes]
     557 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:557:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     557 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   mm/shmem.c:1686:20: warning: unused function 'shmem_show_mpol' [-Wunused-function]
    1686 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
         |                    ^~~~~~~~~~~~~~~
   2 warnings generated.


vim +/register_ftrace_direct_hash +557 include/linux/ftrace.h

   556	
 > 557	int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
   558	{
   559		return -ENODEV;
   560	}
   561	

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