[akpm-mm:mm-new 123/137] arch/s390/mm/mmap.c:188:3: error: call to undeclared function 'mm_flag_set'; ISO C99 and later do not support implicit function declarations

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

Hi Lorenzo,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
head:   694c8e78f486b09137ee3efadae044d01aba971b
commit: 70fd92efa9e96967353bb39665bac8f5276aaaae [123/137] mm: convert arch-specific code to mm_flags_*() accessors
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20250813/202508132154.feFNDPyq-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 3769ce013be2879bf0b329c14a16f5cb766f26ce)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250813/202508132154.feFNDPyq-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/202508132154.feFNDPyq-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/s390/mm/mmap.c:188:3: error: call to undeclared function 'mm_flag_set'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     188 |                 mm_flag_set(MMF_TOPDOWN, mm);
         |                 ^
   arch/s390/mm/mmap.c:188:3: note: did you mean 'mm_flags_set'?
   include/linux/mm.h:740:20: note: 'mm_flags_set' declared here
     740 | static inline void mm_flags_set(int flag, struct mm_struct *mm)
         |                    ^
   1 error generated.


vim +/mm_flag_set +188 arch/s390/mm/mmap.c

   167	
   168	/*
   169	 * This function, called very early during the creation of a new
   170	 * process VM image, sets up which VM layout function to use:
   171	 */
   172	void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
   173	{
   174		unsigned long random_factor = 0UL;
   175	
   176		if (current->flags & PF_RANDOMIZE)
   177			random_factor = arch_mmap_rnd();
   178	
   179		/*
   180		 * Fall back to the standard layout if the personality
   181		 * bit is set, or if the expected stack growth is unlimited:
   182		 */
   183		if (mmap_is_legacy(rlim_stack)) {
   184			mm->mmap_base = mmap_base_legacy(random_factor);
   185			mm_flags_clear(MMF_TOPDOWN, mm);
   186		} else {
   187			mm->mmap_base = mmap_base(random_factor, rlim_stack);
 > 188			mm_flag_set(MMF_TOPDOWN, mm);
   189		}
   190	}
   191	

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