Re: [RFC 04/10] ftrace: Add modify_ftrace_direct_hash function

Re: [RFC 04/10] ftrace: Add modify_ftrace_direct_hash function

[kernel test robot]

Hi Jiri,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on trace/for-next]
[also build test WARNING on bpf-next/net bpf-next/master bpf/master linus/master v6.16 next-20250729]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jiri-Olsa/ftrace-Make-alloc_and_copy_ftrace_hash-direct-friendly/20250729-183143
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/20250729102813.1531457-5-jolsa%40kernel.org
patch subject: [RFC 04/10] ftrace: Add modify_ftrace_direct_hash function
config: x86_64-buildonly-randconfig-003-20250730 (https://download.01.org/0day-ci/archive/20250730/202507300954.QwO5Jhbb-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250730/202507300954.QwO5Jhbb-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/202507300954.QwO5Jhbb-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from kernel/events/callchain.c:11:
   In file included from include/linux/perf_event.h:43:
   include/linux/ftrace.h:559:5: warning: no previous prototype for function 'register_ftrace_direct_hash' [-Wmissing-prototypes]
     559 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:559:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     559 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   include/linux/ftrace.h:564:5: warning: no previous prototype for function 'unregister_ftrace_direct_hash' [-Wmissing-prototypes]
     564 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:564:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     564 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
>> include/linux/ftrace.h:569:5: warning: no previous prototype for function 'modify_ftrace_direct_hash' [-Wmissing-prototypes]
     569 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         |     ^
   include/linux/ftrace.h:569:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     569 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         | ^
         | static 
   3 warnings generated.
--
   In file included from kernel/events/core.c:34:
   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:559:5: warning: no previous prototype for function 'register_ftrace_direct_hash' [-Wmissing-prototypes]
     559 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:559:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     559 | int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
   include/linux/ftrace.h:564:5: warning: no previous prototype for function 'unregister_ftrace_direct_hash' [-Wmissing-prototypes]
     564 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         |     ^
   include/linux/ftrace.h:564:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     564 | int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
         | ^
         | static 
>> include/linux/ftrace.h:569:5: warning: no previous prototype for function 'modify_ftrace_direct_hash' [-Wmissing-prototypes]
     569 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         |     ^
   include/linux/ftrace.h:569:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     569 | int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
         | ^
         | static 
   kernel/events/core.c:215:20: warning: unused function 'class_perf_ctx_lock_destructor' [-Wunused-function]
     215 | static inline void class_perf_ctx_lock_destructor(class_perf_ctx_lock_t *_T)
         |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/events/core.c:219:1: warning: unused function 'class_perf_ctx_lock_constructor' [-Wunused-function]
     219 | class_perf_ctx_lock_constructor(struct perf_cpu_context *cpuctx,
         | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   5 warnings generated.


vim +/modify_ftrace_direct_hash +569 include/linux/ftrace.h

   563	
 > 564	int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash)
   565	{
   566		return -ENODEV;
   567	}
   568	
 > 569	int modify_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash *hash, bool do_direct_lock)
   570	{
   571		return -ENODEV;
   572	}
   573	

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