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

  /* internal.h: mm/ internal definitions
   *
   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)

   */

  #ifndef __MM_INTERNAL_H
  #define __MM_INTERNAL_H

  #include <linux/fs.h>

  #include <linux/mm.h>

  #include <linux/pagemap.h>

  #include <linux/tracepoint-defs.h>

  /*
   * The set of flags that only affect watermark checking and reclaim
   * behaviour. This is used by the MM to obey the caller constraints
   * about IO, FS and watermark checking while ignoring placement
   * hints such as HIGHMEM usage.
   */
  #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\

  			__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\

  			__GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\
  			__GFP_ATOMIC)

  
  /* The GFP flags allowed during early boot */
  #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
  
  /* Control allocation cpuset and node placement constraints */
  #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
  
  /* Do not use these with a slab allocator */
  #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)

  void page_writeback_init(void);

  vm_fault_t do_swap_page(struct vm_fault *vmf);

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

  static inline bool can_madv_lru_vma(struct vm_area_struct *vma)

  {
  	return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));
  }

  void unmap_page_range(struct mmu_gather *tlb,
  			     struct vm_area_struct *vma,
  			     unsigned long addr, unsigned long end,
  			     struct zap_details *details);

  void do_page_cache_ra(struct readahead_control *, unsigned long nr_to_read,
  		unsigned long lookahead_size);

  void force_page_cache_ra(struct readahead_control *, struct file_ra_state *,
  		unsigned long nr);

  static inline void force_page_cache_readahead(struct address_space *mapping,
  		struct file *file, pgoff_t index, unsigned long nr_to_read)
  {
  	DEFINE_READAHEAD(ractl, file, mapping, index);

  	force_page_cache_ra(&ractl, &file->f_ra, nr_to_read);

  }

  struct page *find_get_entry(struct address_space *mapping, pgoff_t index);
  struct page *find_lock_entry(struct address_space *mapping, pgoff_t index);

  /**
   * page_evictable - test whether a page is evictable
   * @page: the page to test
   *
   * Test whether page is evictable--i.e., should be placed on active/inactive
   * lists vs unevictable list.
   *
   * Reasons page might not be evictable:
   * (1) page's mapping marked unevictable
   * (2) page is part of an mlocked VMA
   *
   */
  static inline bool page_evictable(struct page *page)
  {
  	bool ret;
  
  	/* Prevent address_space of inode and swap cache from being freed */
  	rcu_read_lock();
  	ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
  	rcu_read_unlock();
  	return ret;
  }

  /*

   * Turn a non-refcounted page (->_refcount == 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(page_ref_count(page), page);

  	set_page_count(page, 1);

  }

  extern unsigned long highest_memmap_pfn;

  /*

   * Maximum number of reclaim retries without progress before the OOM
   * killer is consider the only way forward.
   */
  #define MAX_RECLAIM_RETRIES 16
  
  /*

   * in mm/vmscan.c:
   */

  extern int isolate_lru_page(struct page *page);

  extern void putback_lru_page(struct page *page);

  /*

   * 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 highest_zoneidx are initialized only once in

   * __alloc_pages_nodemask() and then never change.
   *

   * zonelist, preferred_zone and highest_zoneidx 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 structure

   * by a const pointer.
   */
  struct alloc_context {
  	struct zonelist *zonelist;
  	nodemask_t *nodemask;

  	struct zoneref *preferred_zoneref;

  	int migratetype;

  
  	/*
  	 * highest_zoneidx represents highest usable zone index of
  	 * the allocation request. Due to the nature of the zone,
  	 * memory on lower zone than the highest_zoneidx will be
  	 * protected by lowmem_reserve[highest_zoneidx].
  	 *
  	 * highest_zoneidx is also used by reclaim/compaction to limit
  	 * the target zone since higher zone than this index cannot be
  	 * usable for this allocation request.
  	 */
  	enum zone_type highest_zoneidx;

  	bool spread_dirty_pages;

  };
  
  /*

   * 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_pfn(unsigned long page_pfn, unsigned int order)

  {

  	return page_pfn ^ (1 << order);

  }

  extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
  				unsigned long end_pfn, struct zone *zone);
  
  static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
  				unsigned long end_pfn, struct zone *zone)
  {
  	if (zone->contiguous)
  		return pfn_to_page(start_pfn);
  
  	return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
  }

  extern int __isolate_free_page(struct page *page, unsigned int order);

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

  extern void memblock_free_pages(struct page *page, unsigned long pfn,

  					unsigned int order);

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

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

  extern void post_alloc_hook(struct page *page, unsigned int order,
  					gfp_t gfp_flags);

  extern int user_min_free_kbytes;

  extern void zone_pcp_update(struct zone *zone);
  extern void zone_pcp_reset(struct zone *zone);

  #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 int nr_freepages;	/* Number of isolated free pages */
  	unsigned int nr_migratepages;	/* Number of pages to migrate */

  	unsigned long free_pfn;		/* isolate_freepages search base */
  	unsigned long migrate_pfn;	/* isolate_migratepages search base */

  	unsigned long fast_start_pfn;	/* a pfn to start linear scan from */

  	struct zone *zone;
  	unsigned long total_migrate_scanned;
  	unsigned long total_free_scanned;

  	unsigned short fast_search_fail;/* failures to use free list searches */
  	short search_order;		/* order to start a fast search at */

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

  	int migratetype;		/* migratetype of direct compactor */

  	const unsigned int alloc_flags;	/* alloc flags of a direct compactor */

  	const int highest_zoneidx;	/* zone index of a direct compactor */

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

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

  	bool no_set_skip_hint;		/* Don't mark blocks for skipping */

  	bool ignore_block_suitable;	/* Scan blocks considered unsuitable */

  	bool direct_compaction;		/* False from kcompactd or /proc/... */

  	bool proactive_compaction;	/* kcompactd proactive compaction */

  	bool whole_zone;		/* Whole zone should/has been scanned */

  	bool contended;			/* Signal lock or sched contention */

  	bool rescan;			/* Rescanning the same pageblock */

  	bool alloc_contig;		/* alloc_contig_range allocation */

  };

  /*
   * Used in direct compaction when a page should be taken from the freelists
   * immediately when one is created during the free path.
   */
  struct capture_control {
  	struct compact_control *cc;
  	struct page *page;
  };

  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 buddy_order_unsafe() below.

   */

  static inline unsigned int buddy_order(struct page *page)

  {

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

  	return page_private(page);
  }

  /*

   * Like buddy_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 buddy_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;
  }

  /*
   * These three helpers classifies VMAs for virtual memory accounting.
   */
  
  /*
   * Executable code area - executable, not writable, not stack
   */

  static inline bool is_exec_mapping(vm_flags_t flags)
  {

  	return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;

  }

  /*
   * Stack area - atomatically grows in one direction
   *
   * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
   * do_mmap() forbids all other combinations.
   */

  static inline bool is_stack_mapping(vm_flags_t flags)
  {

  	return (flags & VM_STACK) == VM_STACK;

  }

  /*
   * Data area - private, writable, not stack
   */

  static inline bool is_data_mapping(vm_flags_t flags)
  {

  	return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;

  }

  /* mm/util.c */
  void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,

  		struct vm_area_struct *prev);

  void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);

  #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_lock 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_misplaced_transhuge_page()
   * (because that does not go through the full procedure of migration ptes):
   * to migrate the Mlocked page flag; update statistics.

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

  	if (TestClearPageMlocked(page)) {

  		int nr_pages = thp_nr_pages(page);

  		/* Holding pmd lock, no change in irq context: __mod is safe */

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

  		SetPageMlocked(newpage);

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

  	}

  }

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

  /*
   * At what user virtual address is page expected in @vma?
   */
  static inline unsigned long
  __vma_address(struct page *page, struct vm_area_struct *vma)
  {
  	pgoff_t pgoff = page_to_pgoff(page);
  	return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
  }
  
  static inline unsigned long
  vma_address(struct page *page, struct vm_area_struct *vma)
  {

  	unsigned long start, end;
  
  	start = __vma_address(page, vma);

  	end = start + thp_size(page) - PAGE_SIZE;

  
  	/* page should be within @vma mapping range */

  	VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma);

  	return max(start, vma->vm_start);

  }

  static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
  						    struct file *fpin)
  {
  	int flags = vmf->flags;
  
  	if (fpin)
  		return fpin;
  
  	/*
  	 * FAULT_FLAG_RETRY_NOWAIT means we don't want to wait on page locks or

  	 * anything, so we only pin the file and drop the mmap_lock if only

  	 * FAULT_FLAG_ALLOW_RETRY is set, while this is the first attempt.

  	 */

  	if (fault_flag_allow_retry_first(flags) &&
  	    !(flags & FAULT_FLAG_RETRY_NOWAIT)) {

  		fpin = get_file(vmf->vma->vm_file);

  		mmap_read_unlock(vmf->vma->vm_mm);

  	}
  	return fpin;
  }

  #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;
  }

  /* 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) \

  			pr_warn("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_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_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 NODE_RECLAIM_NOSCAN	-2
  #define NODE_RECLAIM_FULL	-1
  #define NODE_RECLAIM_SOME	0
  #define NODE_RECLAIM_SUCCESS	1

  #ifdef CONFIG_NUMA
  extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
  #else
  static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
  				unsigned int order)
  {
  	return NODE_RECLAIM_NOSCAN;
  }
  #endif

  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  __must_check vm_mmap_pgoff(struct file *, unsigned long,

          unsigned long, unsigned long,

          unsigned long, unsigned long);

  
  extern void set_pageblock_order(void);

  unsigned int 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)

  /*
   * Only MMU archs have async oom victim reclaim - aka oom_reaper so we
   * cannot assume a reduced access to memory reserves is sufficient for
   * !MMU
   */
  #ifdef CONFIG_MMU
  #define ALLOC_OOM		0x08
  #else
  #define ALLOC_OOM		ALLOC_NO_WATERMARKS
  #endif

  #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 */
  #ifdef CONFIG_ZONE_DMA32
  #define ALLOC_NOFRAGMENT	0x100 /* avoid mixing pageblock types */
  #else
  #define ALLOC_NOFRAGMENT	  0x0
  #endif

  #define ALLOC_KSWAPD		0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */

  enum ttu_flags;
  struct tlbflush_unmap_batch;

  
  /*
   * only for MM internal work items which do not depend on
   * any allocations or locks which might depend on allocations
   */
  extern struct workqueue_struct *mm_percpu_wq;

  #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
  void try_to_unmap_flush(void);

  void try_to_unmap_flush_dirty(void);

  void flush_tlb_batched_pending(struct mm_struct *mm);

  #else
  static inline void try_to_unmap_flush(void)
  {
  }

  static inline void try_to_unmap_flush_dirty(void)
  {
  }

  static inline void flush_tlb_batched_pending(struct mm_struct *mm)
  {
  }

  #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */

  
  extern const struct trace_print_flags pageflag_names[];
  extern const struct trace_print_flags vmaflag_names[];
  extern const struct trace_print_flags gfpflag_names[];

  static inline bool is_migrate_highatomic(enum migratetype migratetype)
  {
  	return migratetype == MIGRATE_HIGHATOMIC;
  }
  
  static inline bool is_migrate_highatomic_page(struct page *page)
  {
  	return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
  }

  void setup_zone_pageset(struct zone *zone);

  
  struct migration_target_control {
  	int nid;		/* preferred node id */
  	nodemask_t *nmask;
  	gfp_t gfp_mask;
  };

  #endif	/* __MM_INTERNAL_H */