text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef __LINUX_MEMORY_HOTPLUG_H
  #define __LINUX_MEMORY_HOTPLUG_H
  
  #include <linux/mmzone.h>
  #include <linux/spinlock.h>
  #include <linux/notifier.h>
  #include <linux/bug.h>
  
  struct page;
  struct zone;
  struct pglist_data;
  struct mem_section;
  struct memory_block;
  struct resource;
  struct vmem_altmap;
  
  #ifdef CONFIG_MEMORY_HOTPLUG
  /*
   * Return page for the valid pfn only if the page is online. All pfn
   * walkers which rely on the fully initialized page->flags and others
   * should use this rather than pfn_valid && pfn_to_page
   */
  #define pfn_to_online_page(pfn)					   \
  ({								   \
  	struct page *___page = NULL;				   \
  	unsigned long ___pfn = pfn;				   \
  	unsigned long ___nr = pfn_to_section_nr(___pfn);	   \
  								   \
  	if (___nr < NR_MEM_SECTIONS && online_section_nr(___nr) && \
  	    pfn_valid_within(___pfn))				   \
  		___page = pfn_to_page(___pfn);			   \
  	___page;						   \
  })
  
  /*
   * Types for free bootmem stored in page->lru.next. These have to be in
   * some random range in unsigned long space for debugging purposes.
   */
  enum {
  	MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE = 12,
  	SECTION_INFO = MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE,
  	MIX_SECTION_INFO,
  	NODE_INFO,
  	MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE = NODE_INFO,
  };
  
  /* Types for control the zone type of onlined and offlined memory */
  enum {
  	MMOP_OFFLINE = -1,
  	MMOP_ONLINE_KEEP,
  	MMOP_ONLINE_KERNEL,
  	MMOP_ONLINE_MOVABLE,
  };
  
  /*
   * Zone resizing functions
   *
   * Note: any attempt to resize a zone should has pgdat_resize_lock()
   * zone_span_writelock() both held. This ensure the size of a zone
   * can't be changed while pgdat_resize_lock() held.
   */
  static inline unsigned zone_span_seqbegin(struct zone *zone)
  {
  	return read_seqbegin(&zone->span_seqlock);
  }
  static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
  {
  	return read_seqretry(&zone->span_seqlock, iv);
  }
  static inline void zone_span_writelock(struct zone *zone)
  {
  	write_seqlock(&zone->span_seqlock);
  }
  static inline void zone_span_writeunlock(struct zone *zone)
  {
  	write_sequnlock(&zone->span_seqlock);
  }
  static inline void zone_seqlock_init(struct zone *zone)
  {
  	seqlock_init(&zone->span_seqlock);
  }
  extern int zone_grow_free_lists(struct zone *zone, unsigned long new_nr_pages);
  extern int zone_grow_waitqueues(struct zone *zone, unsigned long nr_pages);
  extern int add_one_highpage(struct page *page, int pfn, int bad_ppro);
  /* VM interface that may be used by firmware interface */
  extern int online_pages(unsigned long, unsigned long, int);
  extern int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
  	unsigned long *valid_start, unsigned long *valid_end);
  extern void __offline_isolated_pages(unsigned long, unsigned long);
  
  typedef void (*online_page_callback_t)(struct page *page);
  
  extern int set_online_page_callback(online_page_callback_t callback);
  extern int restore_online_page_callback(online_page_callback_t callback);
  
  extern void __online_page_set_limits(struct page *page);
  extern void __online_page_increment_counters(struct page *page);
  extern void __online_page_free(struct page *page);
  
  extern int try_online_node(int nid);
  
  extern bool memhp_auto_online;
  /* If movable_node boot option specified */
  extern bool movable_node_enabled;
  static inline bool movable_node_is_enabled(void)
  {
  	return movable_node_enabled;
  }
  
  extern void arch_remove_memory(int nid, u64 start, u64 size,
  			       struct vmem_altmap *altmap);
  extern void __remove_pages(unsigned long start_pfn, unsigned long nr_pages,
  			   struct vmem_altmap *altmap);
  
  /* reasonably generic interface to expand the physical pages */
  extern int __add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
  		struct vmem_altmap *altmap, bool want_memblock);
  
  #ifndef CONFIG_ARCH_HAS_ADD_PAGES
  static inline int add_pages(int nid, unsigned long start_pfn,
  		unsigned long nr_pages, struct vmem_altmap *altmap,
  		bool want_memblock)
  {
  	return __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
  }
  #else /* ARCH_HAS_ADD_PAGES */
  int add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
  		struct vmem_altmap *altmap, bool want_memblock);
  #endif /* ARCH_HAS_ADD_PAGES */
  
  #ifdef CONFIG_NUMA
  extern int memory_add_physaddr_to_nid(u64 start);
  #else
  static inline int memory_add_physaddr_to_nid(u64 start)
  {
  	return 0;
  }
  #endif
  
  #ifdef CONFIG_HAVE_ARCH_NODEDATA_EXTENSION
  /*
   * For supporting node-hotadd, we have to allocate a new pgdat.
   *
   * If an arch has generic style NODE_DATA(),
   * node_data[nid] = kzalloc() works well. But it depends on the architecture.
   *
   * In general, generic_alloc_nodedata() is used.
   * Now, arch_free_nodedata() is just defined for error path of node_hot_add.
   *
   */
  extern pg_data_t *arch_alloc_nodedata(int nid);
  extern void arch_free_nodedata(pg_data_t *pgdat);
  extern void arch_refresh_nodedata(int nid, pg_data_t *pgdat);
  
  #else /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */
  
  #define arch_alloc_nodedata(nid)	generic_alloc_nodedata(nid)
  #define arch_free_nodedata(pgdat)	generic_free_nodedata(pgdat)
  
  #ifdef CONFIG_NUMA
  /*
   * If ARCH_HAS_NODEDATA_EXTENSION=n, this func is used to allocate pgdat.
   * XXX: kmalloc_node() can't work well to get new node's memory at this time.
   *	Because, pgdat for the new node is not allocated/initialized yet itself.
   *	To use new node's memory, more consideration will be necessary.
   */
  #define generic_alloc_nodedata(nid)				\
  ({								\
  	kzalloc(sizeof(pg_data_t), GFP_KERNEL);			\
  })
  /*
   * This definition is just for error path in node hotadd.
   * For node hotremove, we have to replace this.
   */
  #define generic_free_nodedata(pgdat)	kfree(pgdat)
  
  extern pg_data_t *node_data[];
  static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
  {
  	node_data[nid] = pgdat;
  }
  
  #else /* !CONFIG_NUMA */
  
  /* never called */
  static inline pg_data_t *generic_alloc_nodedata(int nid)
  {
  	BUG();
  	return NULL;
  }
  static inline void generic_free_nodedata(pg_data_t *pgdat)
  {
  }
  static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)
  {
  }
  #endif /* CONFIG_NUMA */
  #endif /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */
  
  #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
  extern void __init register_page_bootmem_info_node(struct pglist_data *pgdat);
  #else
  static inline void register_page_bootmem_info_node(struct pglist_data *pgdat)
  {
  }
  #endif
  extern void put_page_bootmem(struct page *page);
  extern void get_page_bootmem(unsigned long ingo, struct page *page,
  			     unsigned long type);
  
  void get_online_mems(void);
  void put_online_mems(void);
  
  void mem_hotplug_begin(void);
  void mem_hotplug_done(void);
  
  extern void set_zone_contiguous(struct zone *zone);
  extern void clear_zone_contiguous(struct zone *zone);
  
  #else /* ! CONFIG_MEMORY_HOTPLUG */
  #define pfn_to_online_page(pfn)			\
  ({						\
  	struct page *___page = NULL;		\
  	if (pfn_valid(pfn))			\
  		___page = pfn_to_page(pfn);	\
  	___page;				\
   })
  
  static inline unsigned zone_span_seqbegin(struct zone *zone)
  {
  	return 0;
  }
  static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
  {
  	return 0;
  }
  static inline void zone_span_writelock(struct zone *zone) {}
  static inline void zone_span_writeunlock(struct zone *zone) {}
  static inline void zone_seqlock_init(struct zone *zone) {}
  
  static inline int mhp_notimplemented(const char *func)
  {
  	printk(KERN_WARNING "%s() called, with CONFIG_MEMORY_HOTPLUG disabled\n", func);
  	dump_stack();
  	return -ENOSYS;
  }
  
  static inline void register_page_bootmem_info_node(struct pglist_data *pgdat)
  {
  }
  
  static inline int try_online_node(int nid)
  {
  	return 0;
  }
  
  static inline void get_online_mems(void) {}
  static inline void put_online_mems(void) {}
  
  static inline void mem_hotplug_begin(void) {}
  static inline void mem_hotplug_done(void) {}
  
  static inline bool movable_node_is_enabled(void)
  {
  	return false;
  }
  #endif /* ! CONFIG_MEMORY_HOTPLUG */
  
  #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
  /*
   * pgdat resizing functions
   */
  static inline
  void pgdat_resize_lock(struct pglist_data *pgdat, unsigned long *flags)
  {
  	spin_lock_irqsave(&pgdat->node_size_lock, *flags);
  }
  static inline
  void pgdat_resize_unlock(struct pglist_data *pgdat, unsigned long *flags)
  {
  	spin_unlock_irqrestore(&pgdat->node_size_lock, *flags);
  }
  static inline
  void pgdat_resize_init(struct pglist_data *pgdat)
  {
  	spin_lock_init(&pgdat->node_size_lock);
  }
  #else /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
  /*
   * Stub functions for when hotplug is off
   */
  static inline void pgdat_resize_lock(struct pglist_data *p, unsigned long *f) {}
  static inline void pgdat_resize_unlock(struct pglist_data *p, unsigned long *f) {}
  static inline void pgdat_resize_init(struct pglist_data *pgdat) {}
  #endif /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
  
  #ifdef CONFIG_MEMORY_HOTREMOVE
  
  extern bool is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
  extern void try_offline_node(int nid);
  extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
  extern void remove_memory(int nid, u64 start, u64 size);
  extern void __remove_memory(int nid, u64 start, u64 size);
  
  #else
  static inline bool is_mem_section_removable(unsigned long pfn,
  					unsigned long nr_pages)
  {
  	return false;
  }
  
  static inline void try_offline_node(int nid) {}
  
  static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
  {
  	return -EINVAL;
  }
  
  static inline void remove_memory(int nid, u64 start, u64 size) {}
  static inline void __remove_memory(int nid, u64 start, u64 size) {}
  #endif /* CONFIG_MEMORY_HOTREMOVE */
  
  extern void __ref free_area_init_core_hotplug(int nid);
  extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
  		void *arg, int (*func)(struct memory_block *, void *));
  extern int __add_memory(int nid, u64 start, u64 size);
  extern int add_memory(int nid, u64 start, u64 size);
  extern int add_memory_resource(int nid, struct resource *resource, bool online);
  extern int arch_add_memory(int nid, u64 start, u64 size,
  		struct vmem_altmap *altmap, bool want_memblock);
  extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
  		unsigned long nr_pages, struct vmem_altmap *altmap);
  extern void remove_pfn_range_from_zone(struct zone *zone,
  				       unsigned long start_pfn,
  				       unsigned long nr_pages);
  extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
  extern bool is_memblock_offlined(struct memory_block *mem);
  extern int sparse_add_one_section(int nid, unsigned long start_pfn,
  				  struct vmem_altmap *altmap);
  extern void sparse_remove_one_section(struct mem_section *ms,
  		unsigned long map_offset, struct vmem_altmap *altmap);
  extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
  					  unsigned long pnum);
  extern bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_pages,
  		int online_type);
  extern struct zone *zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
  		unsigned long nr_pages);
  #endif /* __LINUX_MEMORY_HOTPLUG_H */
  