text: /* 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>
  #include <linux/userfaultfd_k.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>
  
  /*
   * For HugeTLB page, there are more metadata to save in the struct page. But
   * the head struct page cannot meet our needs, so we have to abuse other tail
   * struct page to store the metadata. In order to avoid conflicts caused by
   * subsequent use of more tail struct pages, we gather these discrete indexes
   * of tail struct page here.
   */
  enum {
  	SUBPAGE_INDEX_SUBPOOL = 1,	/* reuse page->private */
  #ifdef CONFIG_CGROUP_HUGETLB
  	SUBPAGE_INDEX_CGROUP,		/* reuse page->private */
  	SUBPAGE_INDEX_CGROUP_RSVD,	/* reuse page->private */
  	__MAX_CGROUP_SUBPAGE_INDEX = SUBPAGE_INDEX_CGROUP_RSVD,
  #endif
  	__NR_USED_SUBPAGE,
  };
  
  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 allocated 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 */
  				/* satisfy 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
   * indices 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);
  void clear_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 move_hugetlb_page_tables(struct vm_area_struct *vma,
  			     struct vm_area_struct *new_vma,
  			     unsigned long old_addr, unsigned long new_addr,
  			     unsigned long len);
  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 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);
  #ifdef CONFIG_USERFAULTFD
  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,
  				enum mcopy_atomic_mode mode,
  				struct page **pagep);
  #endif /* CONFIG_USERFAULTFD */
  bool 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);
  int get_hwpoison_huge_page(struct page *page, bool *hugetlb);
  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, struct vm_area_struct *vma,
  		      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, struct vm_area_struct *vma,
  			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);
  void hugetlb_unshare_all_pmds(struct vm_area_struct *vma);
  
  #else /* !CONFIG_HUGETLB_PAGE */
  
  static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
  {
  }
  
  static inline void clear_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 int move_hugetlb_page_tables(struct vm_area_struct *vma,
  					   struct vm_area_struct *new_vma,
  					   unsigned long old_addr,
  					   unsigned long new_addr,
  					   unsigned long len)
  {
  	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();
  }
  
  #ifdef CONFIG_USERFAULTFD
  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,
  						enum mcopy_atomic_mode mode,
  						struct page **pagep)
  {
  	BUG();
  	return 0;
  }
  #endif /* CONFIG_USERFAULTFD */
  
  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 int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
  {
  	return 0;
  }
  
  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 vm_fault_t hugetlb_fault(struct mm_struct *mm,
  			struct vm_area_struct *vma, unsigned long address,
  			unsigned int flags)
  {
  	BUG();
  	return 0;
  }
  
  static inline void hugetlb_unshare_all_pmds(struct vm_area_struct *vma) { }
  
  #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,
  				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,
  		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 */
  
  /*
   * huegtlb page specific state flags.  These flags are located in page.private
   * of the hugetlb head page.  Functions created via the below macros should be
   * used to manipulate these flags.
   *
   * HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
   *	allocation time.  Cleared when page is fully instantiated.  Free
   *	routine checks flag to restore a reservation on error paths.
   *	Synchronization:  Examined or modified by code that knows it has
   *	the only reference to page.  i.e. After allocation but before use
   *	or when the page is being freed.
   * HPG_migratable  - Set after a newly allocated page is added to the page
   *	cache and/or page tables.  Indicates the page is a candidate for
   *	migration.
   *	Synchronization:  Initially set after new page allocation with no
   *	locking.  When examined and modified during migration processing
   *	(isolate, migrate, putback) the hugetlb_lock is held.
   * HPG_temporary - - Set on a page that is temporarily allocated from the buddy
   *	allocator.  Typically used for migration target pages when no pages
   *	are available in the pool.  The hugetlb free page path will
   *	immediately free pages with this flag set to the buddy allocator.
   *	Synchronization: Can be set after huge page allocation from buddy when
   *	code knows it has only reference.  All other examinations and
   *	modifications require hugetlb_lock.
   * HPG_freed - Set when page is on the free lists.
   *	Synchronization: hugetlb_lock held for examination and modification.
   * HPG_vmemmap_optimized - Set when the vmemmap pages of the page are freed.
   */
  enum hugetlb_page_flags {
  	HPG_restore_reserve = 0,
  	HPG_migratable,
  	HPG_temporary,
  	HPG_freed,
  	HPG_vmemmap_optimized,
  	__NR_HPAGEFLAGS,
  };
  
  /*
   * Macros to create test, set and clear function definitions for
   * hugetlb specific page flags.
   */
  #ifdef CONFIG_HUGETLB_PAGE
  #define TESTHPAGEFLAG(uname, flname)				\
  static inline int HPage##uname(struct page *page)		\
  	{ return test_bit(HPG_##flname, &(page->private)); }
  
  #define SETHPAGEFLAG(uname, flname)				\
  static inline void SetHPage##uname(struct page *page)		\
  	{ set_bit(HPG_##flname, &(page->private)); }
  
  #define CLEARHPAGEFLAG(uname, flname)				\
  static inline void ClearHPage##uname(struct page *page)		\
  	{ clear_bit(HPG_##flname, &(page->private)); }
  #else
  #define TESTHPAGEFLAG(uname, flname)				\
  static inline int HPage##uname(struct page *page)		\
  	{ return 0; }
  
  #define SETHPAGEFLAG(uname, flname)				\
  static inline void SetHPage##uname(struct page *page)		\
  	{ }
  
  #define CLEARHPAGEFLAG(uname, flname)				\
  static inline void ClearHPage##uname(struct page *page)		\
  	{ }
  #endif
  
  #define HPAGEFLAG(uname, flname)				\
  	TESTHPAGEFLAG(uname, flname)				\
  	SETHPAGEFLAG(uname, flname)				\
  	CLEARHPAGEFLAG(uname, flname)				\
  
  /*
   * Create functions associated with hugetlb page flags
   */
  HPAGEFLAG(RestoreReserve, restore_reserve)
  HPAGEFLAG(Migratable, migratable)
  HPAGEFLAG(Temporary, temporary)
  HPAGEFLAG(Freed, freed)
  HPAGEFLAG(VmemmapOptimized, vmemmap_optimized)
  
  #ifdef CONFIG_HUGETLB_PAGE
  
  #define HSTATE_NAME_LEN 32
  /* Defines one hugetlb page size */
  struct hstate {
  	struct mutex resize_lock;
  	int next_nid_to_alloc;
  	int next_nid_to_free;
  	unsigned int order;
  	unsigned int demote_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 max_huge_pages_node[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_HUGETLB_PAGE_FREE_VMEMMAP
  	unsigned int nr_free_vmemmap_pages;
  #endif
  #ifdef CONFIG_CGROUP_HUGETLB
  	/* cgroup control files */
  	struct cftype cgroup_files_dfl[8];
  	struct cftype cgroup_files_legacy[10];
  #endif
  	char name[HSTATE_NAME_LEN];
  };
  
  struct huge_bootmem_page {
  	struct list_head list;
  	struct hstate *hstate;
  };
  
  int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list);
  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);
  void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
  				unsigned long address, struct page *page);
  
  /* arch callback */
  int __init __alloc_bootmem_huge_page(struct hstate *h, int nid);
  int __init alloc_bootmem_huge_page(struct hstate *h, int nid);
  bool __init hugetlb_node_alloc_supported(void);
  
  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])
  
  /*
   * hugetlb page subpool pointer located in hpage[1].private
   */
  static inline struct hugepage_subpool *hugetlb_page_subpool(struct page *hpage)
  {
  	return (void *)page_private(hpage + SUBPAGE_INDEX_SUBPOOL);
  }
  
  static inline void hugetlb_set_page_subpool(struct page *hpage,
  					struct hugepage_subpool *subpool)
  {
  	set_page_private(hpage + SUBPAGE_INDEX_SUBPOOL, (unsigned long)subpool);
  }
  
  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, unsigned int shift,
  				       vm_flags_t flags)
  {
  	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;
  }
  
  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 won't 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_init(struct mm_struct *mm)
  {
  	atomic_long_set(&mm->hugetlb_usage, 0);
  }
  
  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 hugepage_subpool *hugetlb_page_subpool(struct page *hpage)
  {
  	return NULL;
  }
  
  static inline int isolate_or_dissolve_huge_page(struct page *page,
  						struct list_head *list)
  {
  	return -ENOMEM;
  }
  
  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 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_count_init(struct mm_struct *mm)
  {
  }
  
  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 */
  
  #ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
  extern bool hugetlb_free_vmemmap_enabled;
  #else
  #define hugetlb_free_vmemmap_enabled	false
  #endif
  
  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
  
  bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr);
  
  #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
  /*
   * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
   * implement this.
   */
  #define flush_hugetlb_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
  #endif
  
  #endif /* _LINUX_HUGETLB_H */
  