Re: [RFC PATCH 1/2] locking: add mutex_lock_nospin()

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

Hi Yafang,

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

[auto build test ERROR on tip/locking/core]
[also build test ERROR on linus/master v7.0-rc2 next-20260305]
[cannot apply to trace/for-next]
[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/Yafang-Shao/locking-add-mutex_lock_nospin/20260304-155633
base:   tip/locking/core
patch link:    https://lore.kernel.org/r/20260304074650.58165-2-laoar.shao%40gmail.com
patch subject: [RFC PATCH 1/2] locking: add mutex_lock_nospin()
config: arm-allnoconfig (https://download.01.org/0day-ci/archive/20260307/202603070239.YyGTDfDj-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project c32caeec8158d634bb71ab8911a6031248b9fc47)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260307/202603070239.YyGTDfDj-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/202603070239.YyGTDfDj-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

>> kernel/locking/mutex.c:299:3: error: call to undeclared function '__mutex_lock_nospin'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     299 |                 __mutex_lock_nospin(lock);
         |                 ^
   kernel/locking/mutex.c:299:3: note: did you mean 'mutex_lock_nospin'?
   kernel/locking/mutex.c:294:14: note: 'mutex_lock_nospin' declared here
     294 | void __sched mutex_lock_nospin(struct mutex *lock)
         |              ^
     295 | {
     296 |         might_sleep();
     297 | 
     298 |         if (!__mutex_trylock_fast(lock))
     299 |                 __mutex_lock_nospin(lock);
         |                 ~~~~~~~~~~~~~~~~~~~
         |                 mutex_lock_nospin
>> kernel/locking/mutex.c:630:48: error: too many arguments to function call, expected 3, have 4
     630 |             mutex_optimistic_spin(lock, ww_ctx, NULL, nospin)) {
         |             ~~~~~~~~~~~~~~~~~~~~~                     ^~~~~~
   kernel/locking/mutex.c:532:1: note: 'mutex_optimistic_spin' declared here
     532 | mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
         | ^                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     533 |                       struct mutex_waiter *waiter)
         |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/locking/mutex.c:731:53: error: too many arguments to function call, expected 3, have 4
     731 |                         if (mutex_optimistic_spin(lock, ww_ctx, &waiter, nospin))
         |                             ~~~~~~~~~~~~~~~~~~~~~                        ^~~~~~
   kernel/locking/mutex.c:532:1: note: 'mutex_optimistic_spin' declared here
     532 | mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
         | ^                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     533 |                       struct mutex_waiter *waiter)
         |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/locking/mutex.c:792:1: warning: no previous prototype for function '__mutex_lock_nospin' [-Wmissing-prototypes]
     792 | __mutex_lock_nospin(struct mutex *lock, unsigned int state, unsigned int subclass,
         | ^
   kernel/locking/mutex.c:791:8: note: declare 'static' if the function is not intended to be used outside of this translation unit
     791 | static int __sched
         |        ^
   1 warning and 3 errors generated.


vim +/__mutex_lock_nospin +299 kernel/locking/mutex.c

   293	
   294	void __sched mutex_lock_nospin(struct mutex *lock)
   295	{
   296		might_sleep();
   297	
   298		if (!__mutex_trylock_fast(lock))
 > 299			__mutex_lock_nospin(lock);
   300	}
   301	#endif
   302	

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