Hi Axel,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on powerpc/next s390/features tip/perf/core linus/master v5.11-rc5 next-20210122]
[cannot apply to hp-parisc/for-next hnaz-linux-mm/master ia64/next sparc-next/master sparc/master]
[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]

url:    https://github.com/0day-ci/linux/commits/Axel-Rasmussen/userfaultfd-add-minor-fault-handling/20210125-104035
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: x86_64-randconfig-a013-20210125 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 12d0753aca22896fda2cf76781b0ee0524d55065)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/b8fb53c3a341b9b853aa3286286c807088311dbd
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Axel-Rasmussen/userfaultfd-add-minor-fault-handling/20210125-104035
        git checkout b8fb53c3a341b9b853aa3286286c807088311dbd
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

   In file included from kernel/sched/core.c:13:
   In file included from kernel/sched/sched.h:53:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   kernel/sched/core.c:2884:20: warning: unused function 'rq_has_pinned_tasks' [-Wunused-function]
   static inline bool rq_has_pinned_tasks(struct rq *rq)
                      ^
   kernel/sched/core.c:4687:20: warning: unused function 'sched_tick_start' [-Wunused-function]
   static inline void sched_tick_start(int cpu) { }
                      ^
   kernel/sched/core.c:4688:20: warning: unused function 'sched_tick_stop' [-Wunused-function]
   static inline void sched_tick_stop(int cpu) { }
                      ^
   4 warnings generated.
--
   In file included from kernel/sched/loadavg.c:9:
   In file included from kernel/sched/sched.h:53:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   1 warning generated.
--
   In file included from kernel/sched/fair.c:23:
   In file included from kernel/sched/sched.h:53:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   kernel/sched/fair.c:5388:6: warning: no previous prototype for function 'init_cfs_bandwidth' [-Wmissing-prototypes]
   void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
        ^
   kernel/sched/fair.c:5388:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
   ^
   static 
   kernel/sched/fair.c:11195:6: warning: no previous prototype for function 'free_fair_sched_group' [-Wmissing-prototypes]
   void free_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11195:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void free_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:11197:5: warning: no previous prototype for function 'alloc_fair_sched_group' [-Wmissing-prototypes]
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
       ^
   kernel/sched/fair.c:11197:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
   ^
   static 
   kernel/sched/fair.c:11202:6: warning: no previous prototype for function 'online_fair_sched_group' [-Wmissing-prototypes]
   void online_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11202:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void online_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:11204:6: warning: no previous prototype for function 'unregister_fair_sched_group' [-Wmissing-prototypes]
   void unregister_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11204:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void unregister_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:486:20: warning: unused function 'list_del_leaf_cfs_rq' [-Wunused-function]
   static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
                      ^
   kernel/sched/fair.c:2985:20: warning: unused function 'account_numa_enqueue' [-Wunused-function]
   static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p)
                      ^
   kernel/sched/fair.c:2989:20: warning: unused function 'account_numa_dequeue' [-Wunused-function]
   static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p)
                      ^
   kernel/sched/fair.c:2993:20: warning: unused function 'update_scan_period' [-Wunused-function]
   static inline void update_scan_period(struct task_struct *p, int new_cpu)
                      ^
   kernel/sched/fair.c:4083:20: warning: unused function 'remove_entity_load_avg' [-Wunused-function]
   static inline void remove_entity_load_avg(struct sched_entity *se) {}
                      ^
   kernel/sched/fair.c:5369:20: warning: unused function 'sync_throttle' [-Wunused-function]
   static inline void sync_throttle(struct task_group *tg, int cpu) {}
                      ^
   kernel/sched/fair.c:5382:19: warning: unused function 'throttled_lb_pair' [-Wunused-function]
   static inline int throttled_lb_pair(struct task_group *tg,
                     ^
   kernel/sched/fair.c:5394:37: warning: unused function 'tg_cfs_bandwidth' [-Wunused-function]
   static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
                                       ^
   kernel/sched/fair.c:5398:20: warning: unused function 'destroy_cfs_bandwidth' [-Wunused-function]
   static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
                      ^
   kernel/sched/fair.c:5399:20: warning: unused function 'update_runtime_enabled' [-Wunused-function]
   static inline void update_runtime_enabled(struct rq *rq) {}
                      ^
   kernel/sched/fair.c:5400:20: warning: unused function 'unthrottle_offline_cfs_rqs' [-Wunused-function]
   static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
                      ^
   17 warnings generated.
--
   In file included from kernel/sched/rt.c:6:
   In file included from kernel/sched/sched.h:53:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   kernel/sched/rt.c:253:6: warning: no previous prototype for function 'free_rt_sched_group' [-Wmissing-prototypes]
   void free_rt_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/rt.c:253:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void free_rt_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/rt.c:255:5: warning: no previous prototype for function 'alloc_rt_sched_group' [-Wmissing-prototypes]
   int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
       ^
   kernel/sched/rt.c:255:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
   ^
   static 
   kernel/sched/rt.c:669:6: warning: no previous prototype for function 'sched_rt_bandwidth_account' [-Wmissing-prototypes]
   bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
        ^
   kernel/sched/rt.c:669:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
   ^
   static 
   kernel/sched/rt.c:421:20: warning: unused function 'need_pull_rt_task' [-Wunused-function]
   static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
                      ^
   kernel/sched/rt.c:426:20: warning: unused function 'pull_rt_task' [-Wunused-function]
   static inline void pull_rt_task(struct rq *this_rq)
                      ^
   kernel/sched/rt.c:476:20: warning: unused function 'rt_task_fits_capacity' [-Wunused-function]
   static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
                      ^
   kernel/sched/rt.c:1113:6: warning: unused function 'inc_rt_prio_smp' [-Wunused-function]
   void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
        ^
   kernel/sched/rt.c:1115:6: warning: unused function 'dec_rt_prio_smp' [-Wunused-function]
   void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
        ^
   9 warnings generated.
--
   In file included from kernel/sched/deadline.c:18:
   In file included from kernel/sched/sched.h:53:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   kernel/sched/deadline.c:700:20: warning: unused function 'need_pull_dl_task' [-Wunused-function]
   static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
                      ^
   kernel/sched/deadline.c:705:20: warning: unused function 'pull_dl_task' [-Wunused-function]
   static inline void pull_dl_task(struct rq *rq)
                      ^
   3 warnings generated.
--
   In file included from mm/page_alloc.c:61:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   mm/page_alloc.c:3597:15: warning: no previous prototype for function 'should_fail_alloc_page' [-Wmissing-prototypes]
   noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
                 ^
   mm/page_alloc.c:3597:10: note: declare 'static' if the function is not intended to be used outside of this translation unit
   noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
            ^
            static 
   mm/page_alloc.c:6258:23: warning: no previous prototype for function 'memmap_init' [-Wmissing-prototypes]
   void __meminit __weak memmap_init(unsigned long size, int nid,
                         ^
   mm/page_alloc.c:6258:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __meminit __weak memmap_init(unsigned long size, int nid,
   ^
   static 
   3 warnings generated.
--
   In file included from mm/hugetlb.c:39:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^

quoted

mm/hugetlb.c:4659:13: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                               enum mcopy_atomic_mode mode,
                                    ^
   mm/hugetlb.c:4654:5: error: conflicting types for 'hugetlb_mcopy_atomic_pte'
   int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
       ^
   include/linux/hugetlb.h:138:5: note: previous declaration is here
   int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
       ^
   mm/hugetlb.c:4659:31: error: variable has incomplete type 'enum mcopy_atomic_mode'
                               enum mcopy_atomic_mode mode,
                                                      ^
   mm/hugetlb.c:4659:13: note: forward declaration of 'enum mcopy_atomic_mode'
                               enum mcopy_atomic_mode mode,
                                    ^
   mm/hugetlb.c:4675:25: error: use of undeclared identifier 'MCOPY_ATOMIC_CONTINUE'
           if (!*pagep && mode != MCOPY_ATOMIC_CONTINUE) {
                                  ^
   mm/hugetlb.c:4692:21: error: use of undeclared identifier 'MCOPY_ATOMIC_CONTINUE'
           } else if (mode == MCOPY_ATOMIC_CONTINUE) {
                              ^
   mm/hugetlb.c:4711:27: error: use of undeclared identifier 'MCOPY_ATOMIC_CONTINUE'
           if (vm_shared && mode != MCOPY_ATOMIC_CONTINUE) {
                                    ^
   mm/hugetlb.c:4771:14: error: use of undeclared identifier 'MCOPY_ATOMIC_CONTINUE'
           if (mode != MCOPY_ATOMIC_CONTINUE)
                       ^
   2 warnings and 6 errors generated.
--
   In file included from mm/z3fold.c:33:
   In file included from include/linux/migrate.h:8:

quoted

include/linux/hugetlb.h:142:10: warning: declaration of 'enum mcopy_atomic_mode' will not be visible outside of this function [-Wvisibility]

                                   enum mcopy_atomic_mode mode,
                                        ^
   mm/z3fold.c:287:37: warning: unused function 'handle_to_z3fold_header' [-Wunused-function]
   static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h)
                                       ^
   2 warnings generated.


vim +142 include/linux/hugetlb.h

   108	
   109	void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
   110	int hugetlb_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *);
   111	int hugetlb_overcommit_handler(struct ctl_table *, int, void *, size_t *,
   112			loff_t *);
   113	int hugetlb_treat_movable_handler(struct ctl_table *, int, void *, size_t *,
   114			loff_t *);
   115	int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int, void *, size_t *,
   116			loff_t *);
   117	
   118	int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
   119	long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
   120				 struct page **, struct vm_area_struct **,
   121				 unsigned long *, unsigned long *, long, unsigned int,
   122				 int *);
   123	void unmap_hugepage_range(struct vm_area_struct *,
   124				  unsigned long, unsigned long, struct page *);
   125	void __unmap_hugepage_range_final(struct mmu_gather *tlb,
   126				  struct vm_area_struct *vma,
   127				  unsigned long start, unsigned long end,
   128				  struct page *ref_page);
   129	void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
   130					unsigned long start, unsigned long end,
   131					struct page *ref_page);
   132	void hugetlb_report_meminfo(struct seq_file *);
   133	int hugetlb_report_node_meminfo(char *buf, int len, int nid);
   134	void hugetlb_show_meminfo(void);
   135	unsigned long hugetlb_total_pages(void);
   136	vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
   137				unsigned long address, unsigned int flags);
   138	int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
   139					struct vm_area_struct *dst_vma,
   140					unsigned long dst_addr,
   141					unsigned long src_addr,
 > 142					enum mcopy_atomic_mode mode,
   143					struct page **pagep);
   144	int hugetlb_reserve_pages(struct inode *inode, long from, long to,
   145							struct vm_area_struct *vma,
   146							vm_flags_t vm_flags);
   147	long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
   148							long freed);
   149	bool isolate_huge_page(struct page *page, struct list_head *list);
   150	void putback_active_hugepage(struct page *page);
   151	void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);
   152	void free_huge_page(struct page *page);
   153	void hugetlb_fix_reserve_counts(struct inode *inode);
   154	extern struct mutex *hugetlb_fault_mutex_table;
   155	u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);
   156	

---
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