/* internal.h: mm/ internal definitions
   *
   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */

  #ifndef __MM_INTERNAL_H
  #define __MM_INTERNAL_H

  #include <linux/fs.h>

  #include <linux/mm.h>

  void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  		unsigned long floor, unsigned long ceiling);

  static inline void set_page_count(struct page *page, int v)

  {

  	atomic_set(&page->_count, v);
  }

  extern int __do_page_cache_readahead(struct address_space *mapping,
  		struct file *filp, pgoff_t offset, unsigned long nr_to_read,
  		unsigned long lookahead_size);
  
  /*
   * Submit IO for the read-ahead request in file_ra_state.
   */
  static inline unsigned long ra_submit(struct file_ra_state *ra,
  		struct address_space *mapping, struct file *filp)
  {
  	return __do_page_cache_readahead(mapping, filp,
  					ra->start, ra->size, ra->async_size);
  }

  /*
   * Turn a non-refcounted page (->_count == 0) into refcounted with
   * a count of one.
   */
  static inline void set_page_refcounted(struct page *page)
  {

  	VM_BUG_ON_PAGE(PageTail(page), page);
  	VM_BUG_ON_PAGE(atomic_read(&page->_count), page);

  	set_page_count(page, 1);

  }

  static inline void __get_page_tail_foll(struct page *page,
  					bool get_page_head)
  {
  	/*
  	 * If we're getting a tail page, the elevated page->_count is
  	 * required only in the head page and we will elevate the head
  	 * page->_count and tail page->_mapcount.
  	 *
  	 * We elevate page_tail->_mapcount for tail pages to force
  	 * page_tail->_count to be zero at all times to avoid getting
  	 * false positives from get_page_unless_zero() with
  	 * speculative page access (like in
  	 * page_cache_get_speculative()) on tail pages.
  	 */

  	VM_BUG_ON_PAGE(atomic_read(&page->first_page->_count) <= 0, page);

  	if (get_page_head)
  		atomic_inc(&page->first_page->_count);

  	get_huge_page_tail(page);

  }
  
  /*
   * This is meant to be called as the FOLL_GET operation of
   * follow_page() and it must be called while holding the proper PT
   * lock while the pte (or pmd_trans_huge) is still mapping the page.
   */
  static inline void get_page_foll(struct page *page)
  {
  	if (unlikely(PageTail(page)))
  		/*
  		 * This is safe only because
  		 * __split_huge_page_refcount() can't run under
  		 * get_page_foll() because we hold the proper PT lock.
  		 */
  		__get_page_tail_foll(page, true);
  	else {
  		/*
  		 * Getting a normal page or the head of a compound page
  		 * requires to already have an elevated page->_count.
  		 */

  		VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);

  		atomic_inc(&page->_count);
  	}
  }

  extern unsigned long highest_memmap_pfn;

  /*
   * in mm/vmscan.c:
   */

  extern int isolate_lru_page(struct page *page);

  extern void putback_lru_page(struct page *page);

  extern bool zone_reclaimable(struct zone *zone);

  /*

   * in mm/rmap.c:
   */
  extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
  
  /*

   * in mm/page_alloc.c
   */

  
  /*

   * Structure for holding the mostly immutable allocation parameters passed
   * between functions involved in allocations, including the alloc_pages*
   * family of functions.
   *
   * nodemask, migratetype and high_zoneidx are initialized only once in
   * __alloc_pages_nodemask() and then never change.
   *
   * zonelist, preferred_zone and classzone_idx are set first in
   * __alloc_pages_nodemask() for the fast path, and might be later changed
   * in __alloc_pages_slowpath(). All other functions pass the whole strucure
   * by a const pointer.
   */
  struct alloc_context {
  	struct zonelist *zonelist;
  	nodemask_t *nodemask;
  	struct zone *preferred_zone;
  	int classzone_idx;
  	int migratetype;
  	enum zone_type high_zoneidx;
  };
  
  /*

   * Locate the struct page for both the matching buddy in our
   * pair (buddy1) and the combined O(n+1) page they form (page).
   *
   * 1) Any buddy B1 will have an order O twin B2 which satisfies
   * the following equation:
   *     B2 = B1 ^ (1 << O)
   * For example, if the starting buddy (buddy2) is #8 its order
   * 1 buddy is #10:
   *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
   *
   * 2) Any buddy B will have an order O+1 parent P which
   * satisfies the following equation:
   *     P = B & ~(1 << O)
   *
   * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
   */
  static inline unsigned long
  __find_buddy_index(unsigned long page_idx, unsigned int order)
  {
  	return page_idx ^ (1 << order);
  }
  
  extern int __isolate_free_page(struct page *page, unsigned int order);

  extern void __free_pages_bootmem(struct page *page, unsigned int order);

  extern void prep_compound_page(struct page *page, unsigned long order);

  #ifdef CONFIG_MEMORY_FAILURE
  extern bool is_free_buddy_page(struct page *page);
  #endif

  extern int user_min_free_kbytes;

  #if defined CONFIG_COMPACTION || defined CONFIG_CMA
  
  /*
   * in mm/compaction.c
   */
  /*
   * compact_control is used to track pages being migrated and the free pages
   * they are being migrated to during memory compaction. The free_pfn starts
   * at the end of a zone and migrate_pfn begins at the start. Movable pages
   * are moved to the end of a zone during a compaction run and the run
   * completes when free_pfn <= migrate_pfn
   */
  struct compact_control {
  	struct list_head freepages;	/* List of free pages to migrate to */
  	struct list_head migratepages;	/* List of pages being migrated */
  	unsigned long nr_freepages;	/* Number of isolated free pages */
  	unsigned long nr_migratepages;	/* Number of pages to migrate */
  	unsigned long free_pfn;		/* isolate_freepages search base */
  	unsigned long migrate_pfn;	/* isolate_migratepages search base */

  	enum migrate_mode mode;		/* Async or sync migration mode */

  	bool ignore_skip_hint;		/* Scan blocks even if marked skip */

  	int order;			/* order a direct compactor needs */

  	const gfp_t gfp_mask;		/* gfp mask of a direct compactor */

  	const int alloc_flags;		/* alloc flags of a direct compactor */
  	const int classzone_idx;	/* zone index of a direct compactor */

  	struct zone *zone;

  	int contended;			/* Signal need_sched() or lock
  					 * contention detected during

  					 * compaction
  					 */

  };
  
  unsigned long

  isolate_freepages_range(struct compact_control *cc,
  			unsigned long start_pfn, unsigned long end_pfn);

  unsigned long

  isolate_migratepages_range(struct compact_control *cc,
  			   unsigned long low_pfn, unsigned long end_pfn);

  int find_suitable_fallback(struct free_area *area, unsigned int order,
  			int migratetype, bool only_stealable, bool *can_steal);

  
  #endif

  /*

   * This function returns the order of a free page in the buddy system. In
   * general, page_zone(page)->lock must be held by the caller to prevent the
   * page from being allocated in parallel and returning garbage as the order.
   * If a caller does not hold page_zone(page)->lock, it must guarantee that the

   * page cannot be allocated or merged in parallel. Alternatively, it must
   * handle invalid values gracefully, and use page_order_unsafe() below.

   */
  static inline unsigned long page_order(struct page *page)
  {

  	/* PageBuddy() must be checked by the caller */

  	return page_private(page);
  }

  /*
   * Like page_order(), but for callers who cannot afford to hold the zone lock.
   * PageBuddy() should be checked first by the caller to minimize race window,
   * and invalid values must be handled gracefully.
   *

   * READ_ONCE is used so that if the caller assigns the result into a local

   * variable and e.g. tests it for valid range before using, the compiler cannot
   * decide to remove the variable and inline the page_private(page) multiple
   * times, potentially observing different values in the tests and the actual
   * use of the result.
   */

  #define page_order_unsafe(page)		READ_ONCE(page_private(page))

  static inline bool is_cow_mapping(vm_flags_t flags)
  {
  	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
  }

  /* mm/util.c */
  void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
  		struct vm_area_struct *prev, struct rb_node *rb_parent);

  #ifdef CONFIG_MMU

  extern long populate_vma_page_range(struct vm_area_struct *vma,

  		unsigned long start, unsigned long end, int *nonblocking);

  extern void munlock_vma_pages_range(struct vm_area_struct *vma,
  			unsigned long start, unsigned long end);
  static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
  {
  	munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
  }

  /*

   * must be called with vma's mmap_sem held for read or write, and page locked.

   */
  extern void mlock_vma_page(struct page *page);

  extern unsigned int munlock_vma_page(struct page *page);

  
  /*
   * Clear the page's PageMlocked().  This can be useful in a situation where
   * we want to unconditionally remove a page from the pagecache -- e.g.,
   * on truncation or freeing.
   *
   * It is legal to call this function for any page, mlocked or not.
   * If called for a page that is still mapped by mlocked vmas, all we do
   * is revert to lazy LRU behaviour -- semantics are not broken.
   */

  extern void clear_page_mlock(struct page *page);

  
  /*
   * mlock_migrate_page - called only from migrate_page_copy() to

   * migrate the Mlocked page flag; update statistics.

   */
  static inline void mlock_migrate_page(struct page *newpage, struct page *page)
  {

  	if (TestClearPageMlocked(page)) {
  		unsigned long flags;

  		int nr_pages = hpage_nr_pages(page);

  
  		local_irq_save(flags);

  		__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);

  		SetPageMlocked(newpage);

  		__mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);

  		local_irq_restore(flags);
  	}

  }

  extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);

  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  extern unsigned long vma_address(struct page *page,
  				 struct vm_area_struct *vma);
  #endif

  #else /* !CONFIG_MMU */

  static inline void clear_page_mlock(struct page *page) { }
  static inline void mlock_vma_page(struct page *page) { }
  static inline void mlock_migrate_page(struct page *new, struct page *old) { }

  #endif /* !CONFIG_MMU */

  /*

   * Return the mem_map entry representing the 'offset' subpage within
   * the maximally aligned gigantic page 'base'.  Handle any discontiguity
   * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
   */
  static inline struct page *mem_map_offset(struct page *base, int offset)
  {
  	if (unlikely(offset >= MAX_ORDER_NR_PAGES))

  		return nth_page(base, offset);

  	return base + offset;
  }
  
  /*

   * Iterator over all subpages within the maximally aligned gigantic

   * page 'base'.  Handle any discontiguity in the mem_map.
   */
  static inline struct page *mem_map_next(struct page *iter,
  						struct page *base, int offset)
  {
  	if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
  		unsigned long pfn = page_to_pfn(base) + offset;
  		if (!pfn_valid(pfn))
  			return NULL;
  		return pfn_to_page(pfn);
  	}
  	return iter + 1;
  }
  
  /*

   * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
   * so all functions starting at paging_init should be marked __init
   * in those cases. SPARSEMEM, however, allows for memory hotplug,
   * and alloc_bootmem_node is not used.
   */
  #ifdef CONFIG_SPARSEMEM
  #define __paginginit __meminit
  #else
  #define __paginginit __init
  #endif

  /* Memory initialisation debug and verification */
  enum mminit_level {
  	MMINIT_WARNING,
  	MMINIT_VERIFY,
  	MMINIT_TRACE
  };
  
  #ifdef CONFIG_DEBUG_MEMORY_INIT
  
  extern int mminit_loglevel;
  
  #define mminit_dprintk(level, prefix, fmt, arg...) \
  do { \
  	if (level < mminit_loglevel) { \

  		if (level <= MMINIT_WARNING) \
  			printk(KERN_WARNING "mminit::" prefix " " fmt, ##arg); \
  		else \
  			printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \

  	} \
  } while (0)

  extern void mminit_verify_pageflags_layout(void);
  extern void mminit_verify_page_links(struct page *page,
  		enum zone_type zone, unsigned long nid, unsigned long pfn);

  extern void mminit_verify_zonelist(void);

  #else
  
  static inline void mminit_dprintk(enum mminit_level level,
  				const char *prefix, const char *fmt, ...)
  {
  }

  static inline void mminit_verify_pageflags_layout(void)
  {
  }
  
  static inline void mminit_verify_page_links(struct page *page,
  		enum zone_type zone, unsigned long nid, unsigned long pfn)
  {
  }

  
  static inline void mminit_verify_zonelist(void)
  {
  }

  #endif /* CONFIG_DEBUG_MEMORY_INIT */

  
  /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
  #if defined(CONFIG_SPARSEMEM)
  extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
  				unsigned long *end_pfn);
  #else
  static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
  				unsigned long *end_pfn)
  {
  }
  #endif /* CONFIG_SPARSEMEM */

  #define ZONE_RECLAIM_NOSCAN	-2
  #define ZONE_RECLAIM_FULL	-1
  #define ZONE_RECLAIM_SOME	0
  #define ZONE_RECLAIM_SUCCESS	1

  extern int hwpoison_filter(struct page *p);

  extern u32 hwpoison_filter_dev_major;
  extern u32 hwpoison_filter_dev_minor;

  extern u64 hwpoison_filter_flags_mask;
  extern u64 hwpoison_filter_flags_value;

  extern u64 hwpoison_filter_memcg;

  extern u32 hwpoison_filter_enable;

  
  extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
          unsigned long, unsigned long,
          unsigned long, unsigned long);

  
  extern void set_pageblock_order(void);

  unsigned long reclaim_clean_pages_from_list(struct zone *zone,
  					    struct list_head *page_list);

  /* The ALLOC_WMARK bits are used as an index to zone->watermark */
  #define ALLOC_WMARK_MIN		WMARK_MIN
  #define ALLOC_WMARK_LOW		WMARK_LOW
  #define ALLOC_WMARK_HIGH	WMARK_HIGH
  #define ALLOC_NO_WATERMARKS	0x04 /* don't check watermarks at all */
  
  /* Mask to get the watermark bits */
  #define ALLOC_WMARK_MASK	(ALLOC_NO_WATERMARKS-1)
  
  #define ALLOC_HARDER		0x10 /* try to alloc harder */
  #define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
  #define ALLOC_CPUSET		0x40 /* check for correct cpuset */
  #define ALLOC_CMA		0x80 /* allow allocations from CMA areas */

  #define ALLOC_FAIR		0x100 /* fair zone allocation */

  #endif	/* __MM_INTERNAL_H */