/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_HUGETLB_H
  #define _LINUX_HUGETLB_H

  #include <linux/mm_types.h>

  #include <linux/mmdebug.h>

  #include <linux/fs.h>

  #include <linux/hugetlb_inline.h>

  #include <linux/cgroup.h>

  #include <linux/list.h>
  #include <linux/kref.h>

  #include <linux/pgtable.h>

  #include <linux/gfp.h>

  struct ctl_table;
  struct user_struct;

  struct mmu_gather;

  #ifndef is_hugepd

  typedef struct { unsigned long pd; } hugepd_t;
  #define is_hugepd(hugepd) (0)
  #define __hugepd(x) ((hugepd_t) { (x) })

  #endif

  #ifdef CONFIG_HUGETLB_PAGE
  
  #include <linux/mempolicy.h>

  #include <linux/shm.h>

  #include <asm/tlbflush.h>

  struct hugepage_subpool {
  	spinlock_t lock;
  	long count;

  	long max_hpages;	/* Maximum huge pages or -1 if no maximum. */
  	long used_hpages;	/* Used count against maximum, includes */
  				/* both alloced and reserved pages. */
  	struct hstate *hstate;
  	long min_hpages;	/* Minimum huge pages or -1 if no minimum. */
  	long rsv_hpages;	/* Pages reserved against global pool to */
  				/* sasitfy minimum size. */

  };

  struct resv_map {
  	struct kref refs;

  	spinlock_t lock;

  	struct list_head regions;

  	long adds_in_progress;
  	struct list_head region_cache;
  	long region_cache_count;

  #ifdef CONFIG_CGROUP_HUGETLB
  	/*
  	 * On private mappings, the counter to uncharge reservations is stored
  	 * here. If these fields are 0, then either the mapping is shared, or
  	 * cgroup accounting is disabled for this resv_map.
  	 */
  	struct page_counter *reservation_counter;
  	unsigned long pages_per_hpage;
  	struct cgroup_subsys_state *css;
  #endif

  };

  
  /*
   * Region tracking -- allows tracking of reservations and instantiated pages
   *                    across the pages in a mapping.
   *
   * The region data structures are embedded into a resv_map and protected
   * by a resv_map's lock.  The set of regions within the resv_map represent
   * reservations for huge pages, or huge pages that have already been
   * instantiated within the map.  The from and to elements are huge page
   * indicies into the associated mapping.  from indicates the starting index
   * of the region.  to represents the first index past the end of  the region.
   *
   * For example, a file region structure with from == 0 and to == 4 represents
   * four huge pages in a mapping.  It is important to note that the to element
   * represents the first element past the end of the region. This is used in
   * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
   *
   * Interval notation of the form [from, to) will be used to indicate that
   * the endpoint from is inclusive and to is exclusive.
   */
  struct file_region {
  	struct list_head link;
  	long from;
  	long to;
  #ifdef CONFIG_CGROUP_HUGETLB
  	/*
  	 * On shared mappings, each reserved region appears as a struct
  	 * file_region in resv_map. These fields hold the info needed to
  	 * uncharge each reservation.
  	 */
  	struct page_counter *reservation_counter;
  	struct cgroup_subsys_state *css;
  #endif
  };

  extern struct resv_map *resv_map_alloc(void);
  void resv_map_release(struct kref *ref);

  extern spinlock_t hugetlb_lock;
  extern int hugetlb_max_hstate __read_mostly;
  #define for_each_hstate(h) \
  	for ((h) = hstates; (h) < &hstates[hugetlb_max_hstate]; (h)++)

  struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
  						long min_hpages);

  void hugepage_put_subpool(struct hugepage_subpool *spool);

  void reset_vma_resv_huge_pages(struct vm_area_struct *vma);

  int hugetlb_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *);
  int hugetlb_overcommit_handler(struct ctl_table *, int, void *, size_t *,
  		loff_t *);
  int hugetlb_treat_movable_handler(struct ctl_table *, int, void *, size_t *,
  		loff_t *);
  int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int, void *, size_t *,
  		loff_t *);

  int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);

  long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
  			 struct page **, struct vm_area_struct **,

  			 unsigned long *, unsigned long *, long, unsigned int,
  			 int *);

  void unmap_hugepage_range(struct vm_area_struct *,

  			  unsigned long, unsigned long, struct page *);

  void __unmap_hugepage_range_final(struct mmu_gather *tlb,
  			  struct vm_area_struct *vma,
  			  unsigned long start, unsigned long end,
  			  struct page *ref_page);

  void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
  				unsigned long start, unsigned long end,
  				struct page *ref_page);

  void hugetlb_report_meminfo(struct seq_file *);

  int hugetlb_report_node_meminfo(char *buf, int len, int nid);

  void hugetlb_show_meminfo(void);

  unsigned long hugetlb_total_pages(void);

  vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,

  			unsigned long address, unsigned int flags);

  int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
  				struct vm_area_struct *dst_vma,
  				unsigned long dst_addr,
  				unsigned long src_addr,
  				struct page **pagep);

  int hugetlb_reserve_pages(struct inode *inode, long from, long to,

  						struct vm_area_struct *vma,

  						vm_flags_t vm_flags);

  long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
  						long freed);

  bool isolate_huge_page(struct page *page, struct list_head *list);
  void putback_active_hugepage(struct page *page);

  void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);

  void free_huge_page(struct page *page);

  void hugetlb_fix_reserve_counts(struct inode *inode);

  extern struct mutex *hugetlb_fault_mutex_table;

  u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);

  pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);

  struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage);

  extern int sysctl_hugetlb_shm_group;

  extern struct list_head huge_boot_pages;

  /* arch callbacks */

  pte_t *huge_pte_alloc(struct mm_struct *mm,
  			unsigned long addr, unsigned long sz);

  pte_t *huge_pte_offset(struct mm_struct *mm,
  		       unsigned long addr, unsigned long sz);

  int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
  				unsigned long *addr, pte_t *ptep);

  void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
  				unsigned long *start, unsigned long *end);

  struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
  			      int write);

  struct page *follow_huge_pd(struct vm_area_struct *vma,
  			    unsigned long address, hugepd_t hpd,
  			    int flags, int pdshift);

  struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,

  				pmd_t *pmd, int flags);

  struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,

  				pud_t *pud, int flags);

  struct page *follow_huge_pgd(struct mm_struct *mm, unsigned long address,
  			     pgd_t *pgd, int flags);

  int pmd_huge(pmd_t pmd);

  int pud_huge(pud_t pud);

  unsigned long hugetlb_change_protection(struct vm_area_struct *vma,

  		unsigned long address, unsigned long end, pgprot_t newprot);

  bool is_hugetlb_entry_migration(pte_t pte);

  #else /* !CONFIG_HUGETLB_PAGE */

  static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
  {
  }

  static inline unsigned long hugetlb_total_pages(void)
  {
  	return 0;
  }

  static inline struct address_space *hugetlb_page_mapping_lock_write(
  							struct page *hpage)
  {
  	return NULL;
  }

  static inline int huge_pmd_unshare(struct mm_struct *mm,
  					struct vm_area_struct *vma,
  					unsigned long *addr, pte_t *ptep)

  {
  	return 0;
  }
  
  static inline void adjust_range_if_pmd_sharing_possible(
  				struct vm_area_struct *vma,
  				unsigned long *start, unsigned long *end)
  {
  }

  static inline long follow_hugetlb_page(struct mm_struct *mm,
  			struct vm_area_struct *vma, struct page **pages,
  			struct vm_area_struct **vmas, unsigned long *position,
  			unsigned long *nr_pages, long i, unsigned int flags,
  			int *nonblocking)
  {
  	BUG();
  	return 0;
  }
  
  static inline struct page *follow_huge_addr(struct mm_struct *mm,
  					unsigned long address, int write)
  {
  	return ERR_PTR(-EINVAL);
  }
  
  static inline int copy_hugetlb_page_range(struct mm_struct *dst,
  			struct mm_struct *src, struct vm_area_struct *vma)
  {
  	BUG();
  	return 0;
  }

  static inline void hugetlb_report_meminfo(struct seq_file *m)
  {
  }

  static inline int hugetlb_report_node_meminfo(char *buf, int len, int nid)

  {
  	return 0;
  }

  static inline void hugetlb_show_meminfo(void)
  {
  }

  
  static inline struct page *follow_huge_pd(struct vm_area_struct *vma,
  				unsigned long address, hugepd_t hpd, int flags,
  				int pdshift)
  {
  	return NULL;
  }
  
  static inline struct page *follow_huge_pmd(struct mm_struct *mm,
  				unsigned long address, pmd_t *pmd, int flags)
  {
  	return NULL;
  }
  
  static inline struct page *follow_huge_pud(struct mm_struct *mm,
  				unsigned long address, pud_t *pud, int flags)
  {
  	return NULL;
  }
  
  static inline struct page *follow_huge_pgd(struct mm_struct *mm,
  				unsigned long address, pgd_t *pgd, int flags)
  {
  	return NULL;
  }
  
  static inline int prepare_hugepage_range(struct file *file,
  				unsigned long addr, unsigned long len)
  {
  	return -EINVAL;
  }
  
  static inline int pmd_huge(pmd_t pmd)
  {
  	return 0;
  }
  
  static inline int pud_huge(pud_t pud)
  {
  	return 0;
  }
  
  static inline int is_hugepage_only_range(struct mm_struct *mm,
  					unsigned long addr, unsigned long len)
  {
  	return 0;
  }
  
  static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
  				unsigned long addr, unsigned long end,
  				unsigned long floor, unsigned long ceiling)
  {
  	BUG();
  }
  
  static inline int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
  						pte_t *dst_pte,
  						struct vm_area_struct *dst_vma,
  						unsigned long dst_addr,
  						unsigned long src_addr,
  						struct page **pagep)
  {
  	BUG();
  	return 0;
  }
  
  static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
  					unsigned long sz)
  {
  	return NULL;
  }

  static inline bool isolate_huge_page(struct page *page, struct list_head *list)
  {
  	return false;
  }

  static inline void putback_active_hugepage(struct page *page)
  {
  }
  
  static inline void move_hugetlb_state(struct page *oldpage,
  					struct page *newpage, int reason)
  {
  }
  
  static inline unsigned long hugetlb_change_protection(
  			struct vm_area_struct *vma, unsigned long address,
  			unsigned long end, pgprot_t newprot)

  {
  	return 0;
  }

  static inline void __unmap_hugepage_range_final(struct mmu_gather *tlb,
  			struct vm_area_struct *vma, unsigned long start,
  			unsigned long end, struct page *ref_page)
  {
  	BUG();
  }

  static inline void __unmap_hugepage_range(struct mmu_gather *tlb,
  			struct vm_area_struct *vma, unsigned long start,
  			unsigned long end, struct page *ref_page)
  {
  	BUG();
  }

  static inline vm_fault_t hugetlb_fault(struct mm_struct *mm,

  			struct vm_area_struct *vma, unsigned long address,
  			unsigned int flags)

  {
  	BUG();
  	return 0;
  }

  #endif /* !CONFIG_HUGETLB_PAGE */

  /*
   * hugepages at page global directory. If arch support
   * hugepages at pgd level, they need to define this.
   */
  #ifndef pgd_huge
  #define pgd_huge(x)	0
  #endif

  #ifndef p4d_huge
  #define p4d_huge(x)	0
  #endif

  
  #ifndef pgd_write
  static inline int pgd_write(pgd_t pgd)
  {
  	BUG();
  	return 0;
  }
  #endif

  #define HUGETLB_ANON_FILE "anon_hugepage"

  enum {
  	/*
  	 * The file will be used as an shm file so shmfs accounting rules
  	 * apply
  	 */
  	HUGETLB_SHMFS_INODE     = 1,

  	/*
  	 * The file is being created on the internal vfs mount and shmfs
  	 * accounting rules do not apply
  	 */
  	HUGETLB_ANONHUGE_INODE  = 2,

  };

  #ifdef CONFIG_HUGETLBFS

  struct hugetlbfs_sb_info {

  	long	max_inodes;   /* inodes allowed */
  	long	free_inodes;  /* inodes free */
  	spinlock_t	stat_lock;

  	struct hstate *hstate;

  	struct hugepage_subpool *spool;

  	kuid_t	uid;
  	kgid_t	gid;
  	umode_t mode;

  };

  static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
  {
  	return sb->s_fs_info;
  }

  struct hugetlbfs_inode_info {
  	struct shared_policy policy;
  	struct inode vfs_inode;

  	unsigned int seals;

  };
  
  static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  {
  	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  }

  extern const struct file_operations hugetlbfs_file_operations;

  extern const struct vm_operations_struct hugetlb_vm_ops;

  struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,

  				struct user_struct **user, int creat_flags,
  				int page_size_log);

  static inline bool is_file_hugepages(struct file *file)

  {

  	if (file->f_op == &hugetlbfs_file_operations)

  		return true;

  	return is_file_shm_hugepages(file);

  }

  static inline struct hstate *hstate_inode(struct inode *i)
  {
  	return HUGETLBFS_SB(i->i_sb)->hstate;
  }

  #else /* !CONFIG_HUGETLBFS */

  #define is_file_hugepages(file)			false

  static inline struct file *

  hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
  		struct user_struct **user, int creat_flags,

  		int page_size_log)

  {
  	return ERR_PTR(-ENOSYS);
  }

  static inline struct hstate *hstate_inode(struct inode *i)
  {
  	return NULL;
  }

  #endif /* !CONFIG_HUGETLBFS */

  #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
  unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  					unsigned long len, unsigned long pgoff,
  					unsigned long flags);
  #endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */

  #ifdef CONFIG_HUGETLB_PAGE

  #define HSTATE_NAME_LEN 32

  /* Defines one hugetlb page size */
  struct hstate {

  	int next_nid_to_alloc;
  	int next_nid_to_free;

  	unsigned int order;
  	unsigned long mask;
  	unsigned long max_huge_pages;
  	unsigned long nr_huge_pages;
  	unsigned long free_huge_pages;
  	unsigned long resv_huge_pages;
  	unsigned long surplus_huge_pages;
  	unsigned long nr_overcommit_huge_pages;

  	struct list_head hugepage_activelist;

  	struct list_head hugepage_freelists[MAX_NUMNODES];
  	unsigned int nr_huge_pages_node[MAX_NUMNODES];
  	unsigned int free_huge_pages_node[MAX_NUMNODES];
  	unsigned int surplus_huge_pages_node[MAX_NUMNODES];

  #ifdef CONFIG_CGROUP_HUGETLB
  	/* cgroup control files */

  	struct cftype cgroup_files_dfl[7];
  	struct cftype cgroup_files_legacy[9];

  #endif

  	char name[HSTATE_NAME_LEN];

  };

  struct huge_bootmem_page {
  	struct list_head list;
  	struct hstate *hstate;
  };

  struct page *alloc_huge_page(struct vm_area_struct *vma,
  				unsigned long addr, int avoid_reserve);

  struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,

  				nodemask_t *nmask, gfp_t gfp_mask);

  struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
  				unsigned long address);

  int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
  			pgoff_t idx);

  /* arch callback */

  int __init __alloc_bootmem_huge_page(struct hstate *h);

  int __init alloc_bootmem_huge_page(struct hstate *h);

  void __init hugetlb_add_hstate(unsigned order);

  bool __init arch_hugetlb_valid_size(unsigned long size);

  struct hstate *size_to_hstate(unsigned long size);
  
  #ifndef HUGE_MAX_HSTATE
  #define HUGE_MAX_HSTATE 1
  #endif
  
  extern struct hstate hstates[HUGE_MAX_HSTATE];
  extern unsigned int default_hstate_idx;
  
  #define default_hstate (hstates[default_hstate_idx])

  static inline struct hstate *hstate_file(struct file *f)
  {

  	return hstate_inode(file_inode(f));

  }

  static inline struct hstate *hstate_sizelog(int page_size_log)
  {
  	if (!page_size_log)
  		return &default_hstate;

  
  	return size_to_hstate(1UL << page_size_log);

  }

  static inline struct hstate *hstate_vma(struct vm_area_struct *vma)

  {

  	return hstate_file(vma->vm_file);

  }
  
  static inline unsigned long huge_page_size(struct hstate *h)
  {
  	return (unsigned long)PAGE_SIZE << h->order;
  }

  extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma);

  extern unsigned long vma_mmu_pagesize(struct vm_area_struct *vma);

  static inline unsigned long huge_page_mask(struct hstate *h)
  {
  	return h->mask;
  }
  
  static inline unsigned int huge_page_order(struct hstate *h)
  {
  	return h->order;
  }
  
  static inline unsigned huge_page_shift(struct hstate *h)
  {
  	return h->order + PAGE_SHIFT;
  }

  static inline bool hstate_is_gigantic(struct hstate *h)
  {
  	return huge_page_order(h) >= MAX_ORDER;
  }

  static inline unsigned int pages_per_huge_page(struct hstate *h)
  {
  	return 1 << h->order;
  }
  
  static inline unsigned int blocks_per_huge_page(struct hstate *h)
  {
  	return huge_page_size(h) / 512;
  }
  
  #include <asm/hugetlb.h>

  #ifndef is_hugepage_only_range
  static inline int is_hugepage_only_range(struct mm_struct *mm,
  					unsigned long addr, unsigned long len)
  {
  	return 0;
  }
  #define is_hugepage_only_range is_hugepage_only_range
  #endif

  #ifndef arch_clear_hugepage_flags
  static inline void arch_clear_hugepage_flags(struct page *page) { }
  #define arch_clear_hugepage_flags arch_clear_hugepage_flags
  #endif

  #ifndef arch_make_huge_pte
  static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
  				       struct page *page, int writable)
  {
  	return entry;
  }
  #endif

  static inline struct hstate *page_hstate(struct page *page)
  {

  	VM_BUG_ON_PAGE(!PageHuge(page), page);

  	return size_to_hstate(page_size(page));

  }

  static inline unsigned hstate_index_to_shift(unsigned index)
  {
  	return hstates[index].order + PAGE_SHIFT;
  }

  static inline int hstate_index(struct hstate *h)
  {
  	return h - hstates;
  }

  pgoff_t __basepage_index(struct page *page);
  
  /* Return page->index in PAGE_SIZE units */
  static inline pgoff_t basepage_index(struct page *page)
  {
  	if (!PageCompound(page))
  		return page->index;
  
  	return __basepage_index(page);
  }

  extern int dissolve_free_huge_page(struct page *page);

  extern int dissolve_free_huge_pages(unsigned long start_pfn,
  				    unsigned long end_pfn);

  #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION

  #ifndef arch_hugetlb_migration_supported
  static inline bool arch_hugetlb_migration_supported(struct hstate *h)
  {

  	if ((huge_page_shift(h) == PMD_SHIFT) ||

  		(huge_page_shift(h) == PUD_SHIFT) ||
  			(huge_page_shift(h) == PGDIR_SHIFT))

  		return true;
  	else
  		return false;

  }
  #endif

  #else

  static inline bool arch_hugetlb_migration_supported(struct hstate *h)
  {

  	return false;

  }

  #endif

  
  static inline bool hugepage_migration_supported(struct hstate *h)
  {
  	return arch_hugetlb_migration_supported(h);

  }

  /*
   * Movability check is different as compared to migration check.
   * It determines whether or not a huge page should be placed on
   * movable zone or not. Movability of any huge page should be
   * required only if huge page size is supported for migration.
   * There wont be any reason for the huge page to be movable if
   * it is not migratable to start with. Also the size of the huge
   * page should be large enough to be placed under a movable zone
   * and still feasible enough to be migratable. Just the presence
   * in movable zone does not make the migration feasible.
   *
   * So even though large huge page sizes like the gigantic ones
   * are migratable they should not be movable because its not
   * feasible to migrate them from movable zone.
   */
  static inline bool hugepage_movable_supported(struct hstate *h)
  {
  	if (!hugepage_migration_supported(h))
  		return false;
  
  	if (hstate_is_gigantic(h))
  		return false;
  	return true;
  }

  /* Movability of hugepages depends on migration support. */
  static inline gfp_t htlb_alloc_mask(struct hstate *h)
  {
  	if (hugepage_movable_supported(h))
  		return GFP_HIGHUSER_MOVABLE;
  	else
  		return GFP_HIGHUSER;
  }

  static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
  {
  	gfp_t modified_mask = htlb_alloc_mask(h);
  
  	/* Some callers might want to enforce node */
  	modified_mask |= (gfp_mask & __GFP_THISNODE);

  	modified_mask |= (gfp_mask & __GFP_NOWARN);

  	return modified_mask;
  }

  static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
  					   struct mm_struct *mm, pte_t *pte)
  {
  	if (huge_page_size(h) == PMD_SIZE)
  		return pmd_lockptr(mm, (pmd_t *) pte);
  	VM_BUG_ON(huge_page_size(h) == PAGE_SIZE);
  	return &mm->page_table_lock;
  }

  #ifndef hugepages_supported
  /*
   * Some platform decide whether they support huge pages at boot
   * time. Some of them, such as powerpc, set HPAGE_SHIFT to 0
   * when there is no such support
   */
  #define hugepages_supported() (HPAGE_SHIFT != 0)
  #endif

  void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
  
  static inline void hugetlb_count_add(long l, struct mm_struct *mm)
  {
  	atomic_long_add(l, &mm->hugetlb_usage);
  }
  
  static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
  {
  	atomic_long_sub(l, &mm->hugetlb_usage);
  }

  
  #ifndef set_huge_swap_pte_at
  static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
  					pte_t *ptep, pte_t pte, unsigned long sz)
  {
  	set_huge_pte_at(mm, addr, ptep, pte);
  }
  #endif

  
  #ifndef huge_ptep_modify_prot_start
  #define huge_ptep_modify_prot_start huge_ptep_modify_prot_start
  static inline pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
  						unsigned long addr, pte_t *ptep)
  {
  	return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep);
  }
  #endif
  
  #ifndef huge_ptep_modify_prot_commit
  #define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit
  static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
  						unsigned long addr, pte_t *ptep,
  						pte_t old_pte, pte_t pte)
  {
  	set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
  }
  #endif

  #else	/* CONFIG_HUGETLB_PAGE */

  struct hstate {};

  
  static inline struct page *alloc_huge_page(struct vm_area_struct *vma,
  					   unsigned long addr,
  					   int avoid_reserve)
  {
  	return NULL;
  }

  static inline struct page *

  alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
  			nodemask_t *nmask, gfp_t gfp_mask)

  {
  	return NULL;
  }
  
  static inline struct page *alloc_huge_page_vma(struct hstate *h,
  					       struct vm_area_struct *vma,
  					       unsigned long address)
  {
  	return NULL;
  }
  
  static inline int __alloc_bootmem_huge_page(struct hstate *h)
  {
  	return 0;
  }
  
  static inline struct hstate *hstate_file(struct file *f)
  {
  	return NULL;
  }
  
  static inline struct hstate *hstate_sizelog(int page_size_log)
  {
  	return NULL;
  }
  
  static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
  {
  	return NULL;

  }
  
  static inline struct hstate *page_hstate(struct page *page)
  {
  	return NULL;
  }
  
  static inline unsigned long huge_page_size(struct hstate *h)
  {
  	return PAGE_SIZE;
  }
  
  static inline unsigned long huge_page_mask(struct hstate *h)
  {
  	return PAGE_MASK;
  }
  
  static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
  {
  	return PAGE_SIZE;
  }
  
  static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
  {
  	return PAGE_SIZE;
  }
  
  static inline unsigned int huge_page_order(struct hstate *h)
  {
  	return 0;
  }
  
  static inline unsigned int huge_page_shift(struct hstate *h)
  {
  	return PAGE_SHIFT;
  }

  static inline bool hstate_is_gigantic(struct hstate *h)
  {
  	return false;
  }

  static inline unsigned int pages_per_huge_page(struct hstate *h)
  {
  	return 1;
  }

  
  static inline unsigned hstate_index_to_shift(unsigned index)
  {
  	return 0;
  }
  
  static inline int hstate_index(struct hstate *h)
  {
  	return 0;
  }

  
  static inline pgoff_t basepage_index(struct page *page)
  {
  	return page->index;
  }

  
  static inline int dissolve_free_huge_page(struct page *page)
  {
  	return 0;
  }
  
  static inline int dissolve_free_huge_pages(unsigned long start_pfn,
  					   unsigned long end_pfn)
  {
  	return 0;
  }
  
  static inline bool hugepage_migration_supported(struct hstate *h)
  {
  	return false;
  }

  static inline bool hugepage_movable_supported(struct hstate *h)
  {
  	return false;
  }

  static inline gfp_t htlb_alloc_mask(struct hstate *h)
  {
  	return 0;
  }

  static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
  {
  	return 0;
  }

  static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
  					   struct mm_struct *mm, pte_t *pte)
  {
  	return &mm->page_table_lock;
  }

  
  static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
  {
  }
  
  static inline void hugetlb_count_sub(long l, struct mm_struct *mm)
  {
  }

  
  static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
  					pte_t *ptep, pte_t pte, unsigned long sz)
  {
  }

  #endif	/* CONFIG_HUGETLB_PAGE */

  static inline spinlock_t *huge_pte_lock(struct hstate *h,
  					struct mm_struct *mm, pte_t *pte)
  {
  	spinlock_t *ptl;
  
  	ptl = huge_pte_lockptr(h, mm, pte);
  	spin_lock(ptl);
  	return ptl;
  }

  #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
  extern void __init hugetlb_cma_reserve(int order);
  extern void __init hugetlb_cma_check(void);
  #else
  static inline __init void hugetlb_cma_reserve(int order)
  {
  }
  static inline __init void hugetlb_cma_check(void)
  {
  }
  #endif

  #endif /* _LINUX_HUGETLB_H */