[jolsa-perf:bpf/tracing_multi_5 5/10] kernel/trace/trace.h:907:24: error: incomplete definition of type 'struct ftrace_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: ff2779fb5dbd0d7cdfcdbdaa689bb88eba65e911 [5/10] ftrace: Export some of hash related functions
config: x86_64-buildonly-randconfig-003-20250620 (https://download.01.org/0day-ci/archive/20250620/202506201650.V96wIO7r-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/20250620/202506201650.V96wIO7r-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/202506201650.V96wIO7r-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/trace/trace_printk.c:12:
   include/linux/ftrace.h:575:5: warning: no previous prototype for function 'register_ftrace_direct_hash' [-Wmissing-prototypes]
     575 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:575:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     575 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   include/linux/ftrace.h:580:5: warning: no previous prototype for function 'unregister_ftrace_direct_hash' [-Wmissing-prototypes]
     580 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:580:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     580 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   include/linux/ftrace.h:585:5: warning: no previous prototype for function 'modify_ftrace_direct_hash' [-Wmissing-prototypes]
     585 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         |     ^
   include/linux/ftrace.h:585:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     585 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         | ^
         | static 
   In file included from kernel/trace/trace_printk.c:20:
>> kernel/trace/trace.h:907:24: error: incomplete definition of type 'struct ftrace_hash'
     907 |         return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
         |                           ~~~~^
   include/linux/ftrace.h:84:8: note: forward declaration of 'struct ftrace_hash'
      84 | struct ftrace_hash;
         |        ^
   In file included from kernel/trace/trace_printk.c:20:
   kernel/trace/trace.h:907:40: error: incomplete definition of type 'struct ftrace_hash'
     907 |         return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
         |                                           ~~~~^
   include/linux/ftrace.h:84:8: note: forward declaration of 'struct ftrace_hash'
      84 | struct ftrace_hash;
         |        ^
   3 warnings and 2 errors generated.


vim +907 kernel/trace/trace.h

4046bf023b0647 Namhyung Kim            2017-01-20  904  
eb583cd484f9a7 Arnd Bergmann           2017-01-23  905  static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
4046bf023b0647 Namhyung Kim            2017-01-20  906  {
8c08f0d5c6fb10 Steven Rostedt (VMware  2017-06-26 @907) 	return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
4046bf023b0647 Namhyung Kim            2017-01-20  908  }
4046bf023b0647 Namhyung Kim            2017-01-20  909  

:::::: The code at line 907 was first introduced by commit
:::::: 8c08f0d5c6fb10ff93ffb1cbf416f4f1c3a52a80 ftrace: Have cached module filters be an active filter

:::::: TO: Steven Rostedt (VMware) <rostedt@goodmis.org>
:::::: CC: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki