/*

   * linux/kernel/power/snapshot.c

   *

   * This file provides system snapshot/restore functionality for swsusp.

   *

   * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>

   * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>

   *

   * This file is released under the GPLv2.

   *
   */

  #include <linux/version.h>

  #include <linux/module.h>
  #include <linux/mm.h>
  #include <linux/suspend.h>

  #include <linux/delay.h>

  #include <linux/bitops.h>

  #include <linux/spinlock.h>

  #include <linux/kernel.h>

  #include <linux/pm.h>
  #include <linux/device.h>

  #include <linux/init.h>

  #include <linux/bootmem.h>
  #include <linux/syscalls.h>
  #include <linux/console.h>
  #include <linux/highmem.h>

  #include <linux/list.h>

  #include <linux/slab.h>

  
  #include <asm/uaccess.h>
  #include <asm/mmu_context.h>
  #include <asm/pgtable.h>
  #include <asm/tlbflush.h>
  #include <asm/io.h>

  #include "power.h"

  static int swsusp_page_is_free(struct page *);
  static void swsusp_set_page_forbidden(struct page *);
  static void swsusp_unset_page_forbidden(struct page *);

  /*

   * Number of bytes to reserve for memory allocations made by device drivers
   * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
   * cause image creation to fail (tunable via /sys/power/reserved_size).
   */
  unsigned long reserved_size;
  
  void __init hibernate_reserved_size_init(void)
  {
  	reserved_size = SPARE_PAGES * PAGE_SIZE;
  }
  
  /*

   * Preferred image size in bytes (tunable via /sys/power/image_size).

   * When it is set to N, swsusp will do its best to ensure the image
   * size will not exceed N bytes, but if that is impossible, it will
   * try to create the smallest image possible.

   */

  unsigned long image_size;
  
  void __init hibernate_image_size_init(void)
  {

  	image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;

  }

  /* List of PBEs needed for restoring the pages that were allocated before
   * the suspend and included in the suspend image, but have also been
   * allocated by the "resume" kernel, so their contents cannot be written
   * directly to their "original" page frames.
   */

  struct pbe *restore_pblist;

  /* Pointer to an auxiliary buffer (1 page) */

  static void *buffer;

  /**
   *	@safe_needed - on resume, for storing the PBE list and the image,
   *	we can only use memory pages that do not conflict with the pages

   *	used before suspend.  The unsafe pages have PageNosaveFree set
   *	and we count them using unsafe_pages.

   *

   *	Each allocated image page is marked as PageNosave and PageNosaveFree
   *	so that swsusp_free() can release it.

   */

  #define PG_ANY		0
  #define PG_SAFE		1
  #define PG_UNSAFE_CLEAR	1
  #define PG_UNSAFE_KEEP	0

  static unsigned int allocated_unsafe_pages;

  static void *get_image_page(gfp_t gfp_mask, int safe_needed)

  {
  	void *res;
  
  	res = (void *)get_zeroed_page(gfp_mask);
  	if (safe_needed)

  		while (res && swsusp_page_is_free(virt_to_page(res))) {

  			/* The page is unsafe, mark it for swsusp_free() */

  			swsusp_set_page_forbidden(virt_to_page(res));

  			allocated_unsafe_pages++;

  			res = (void *)get_zeroed_page(gfp_mask);
  		}
  	if (res) {

  		swsusp_set_page_forbidden(virt_to_page(res));
  		swsusp_set_page_free(virt_to_page(res));

  	}
  	return res;
  }
  
  unsigned long get_safe_page(gfp_t gfp_mask)
  {

  	return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
  }

  static struct page *alloc_image_page(gfp_t gfp_mask)
  {

  	struct page *page;
  
  	page = alloc_page(gfp_mask);
  	if (page) {

  		swsusp_set_page_forbidden(page);
  		swsusp_set_page_free(page);

  	}
  	return page;

  }
  
  /**
   *	free_image_page - free page represented by @addr, allocated with

   *	get_image_page (page flags set by it must be cleared)

   */
  
  static inline void free_image_page(void *addr, int clear_nosave_free)
  {

  	struct page *page;
  
  	BUG_ON(!virt_addr_valid(addr));
  
  	page = virt_to_page(addr);

  	swsusp_unset_page_forbidden(page);

  	if (clear_nosave_free)

  		swsusp_unset_page_free(page);

  
  	__free_page(page);

  }

  /* struct linked_page is used to build chains of pages */
  
  #define LINKED_PAGE_DATA_SIZE	(PAGE_SIZE - sizeof(void *))
  
  struct linked_page {
  	struct linked_page *next;
  	char data[LINKED_PAGE_DATA_SIZE];
  } __attribute__((packed));
  
  static inline void
  free_list_of_pages(struct linked_page *list, int clear_page_nosave)
  {
  	while (list) {
  		struct linked_page *lp = list->next;
  
  		free_image_page(list, clear_page_nosave);
  		list = lp;
  	}
  }
  
  /**
    *	struct chain_allocator is used for allocating small objects out of
    *	a linked list of pages called 'the chain'.
    *
    *	The chain grows each time when there is no room for a new object in
    *	the current page.  The allocated objects cannot be freed individually.
    *	It is only possible to free them all at once, by freeing the entire
    *	chain.
    *
    *	NOTE: The chain allocator may be inefficient if the allocated objects
    *	are not much smaller than PAGE_SIZE.
    */
  
  struct chain_allocator {
  	struct linked_page *chain;	/* the chain */
  	unsigned int used_space;	/* total size of objects allocated out
  					 * of the current page
  					 */
  	gfp_t gfp_mask;		/* mask for allocating pages */
  	int safe_needed;	/* if set, only "safe" pages are allocated */
  };
  
  static void
  chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
  {
  	ca->chain = NULL;
  	ca->used_space = LINKED_PAGE_DATA_SIZE;
  	ca->gfp_mask = gfp_mask;
  	ca->safe_needed = safe_needed;
  }
  
  static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
  {
  	void *ret;
  
  	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
  		struct linked_page *lp;

  		lp = get_image_page(ca->gfp_mask, ca->safe_needed);

  		if (!lp)
  			return NULL;
  
  		lp->next = ca->chain;
  		ca->chain = lp;
  		ca->used_space = 0;
  	}
  	ret = ca->chain->data + ca->used_space;
  	ca->used_space += size;
  	return ret;
  }

  /**
   *	Data types related to memory bitmaps.
   *
   *	Memory bitmap is a structure consiting of many linked lists of
   *	objects.  The main list's elements are of type struct zone_bitmap
   *	and each of them corresonds to one zone.  For each zone bitmap
   *	object there is a list of objects of type struct bm_block that

   *	represent each blocks of bitmap in which information is stored.

   *
   *	struct memory_bitmap contains a pointer to the main list of zone
   *	bitmap objects, a struct bm_position used for browsing the bitmap,
   *	and a pointer to the list of pages used for allocating all of the
   *	zone bitmap objects and bitmap block objects.
   *
   *	NOTE: It has to be possible to lay out the bitmap in memory
   *	using only allocations of order 0.  Additionally, the bitmap is
   *	designed to work with arbitrary number of zones (this is over the
   *	top for now, but let's avoid making unnecessary assumptions ;-).
   *
   *	struct zone_bitmap contains a pointer to a list of bitmap block
   *	objects and a pointer to the bitmap block object that has been
   *	most recently used for setting bits.  Additionally, it contains the
   *	pfns that correspond to the start and end of the represented zone.
   *
   *	struct bm_block contains a pointer to the memory page in which

   *	information is stored (in the form of a block of bitmap)
   *	It also contains the pfns that correspond to the start and end of
   *	the represented memory area.

   */
  
  #define BM_END_OF_MAP	(~0UL)

  #define BM_BITS_PER_BLOCK	(PAGE_SIZE * BITS_PER_BYTE)

  
  struct bm_block {

  	struct list_head hook;	/* hook into a list of bitmap blocks */

  	unsigned long start_pfn;	/* pfn represented by the first bit */
  	unsigned long end_pfn;	/* pfn represented by the last bit plus 1 */

  	unsigned long *data;	/* bitmap representing pages */

  };

  static inline unsigned long bm_block_bits(struct bm_block *bb)
  {
  	return bb->end_pfn - bb->start_pfn;
  }

  /* strcut bm_position is used for browsing memory bitmaps */
  
  struct bm_position {

  	struct bm_block *block;

  	int bit;
  };
  
  struct memory_bitmap {

  	struct list_head blocks;	/* list of bitmap blocks */

  	struct linked_page *p_list;	/* list of pages used to store zone
  					 * bitmap objects and bitmap block
  					 * objects
  					 */
  	struct bm_position cur;	/* most recently used bit position */
  };
  
  /* Functions that operate on memory bitmaps */

  static void memory_bm_position_reset(struct memory_bitmap *bm)
  {

  	bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);

  	bm->cur.bit = 0;

  }
  
  static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
  
  /**
   *	create_bm_block_list - create a list of block bitmap objects

   *	@pages - number of pages to track

   *	@list - list to put the allocated blocks into
   *	@ca - chain allocator to be used for allocating memory

   */

  static int create_bm_block_list(unsigned long pages,
  				struct list_head *list,
  				struct chain_allocator *ca)

  {

  	unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);

  
  	while (nr_blocks-- > 0) {
  		struct bm_block *bb;
  
  		bb = chain_alloc(ca, sizeof(struct bm_block));
  		if (!bb)

  			return -ENOMEM;
  		list_add(&bb->hook, list);

  	}

  
  	return 0;

  }

  struct mem_extent {
  	struct list_head hook;
  	unsigned long start;
  	unsigned long end;
  };

  /**

   *	free_mem_extents - free a list of memory extents
   *	@list - list of extents to empty

   */

  static void free_mem_extents(struct list_head *list)
  {
  	struct mem_extent *ext, *aux;

  	list_for_each_entry_safe(ext, aux, list, hook) {
  		list_del(&ext->hook);
  		kfree(ext);
  	}
  }
  
  /**
   *	create_mem_extents - create a list of memory extents representing
   *	                     contiguous ranges of PFNs
   *	@list - list to put the extents into
   *	@gfp_mask - mask to use for memory allocations
   */
  static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)

  {

  	struct zone *zone;

  	INIT_LIST_HEAD(list);

  	for_each_populated_zone(zone) {

  		unsigned long zone_start, zone_end;
  		struct mem_extent *ext, *cur, *aux;

  		zone_start = zone->zone_start_pfn;
  		zone_end = zone->zone_start_pfn + zone->spanned_pages;
  
  		list_for_each_entry(ext, list, hook)
  			if (zone_start <= ext->end)
  				break;

  		if (&ext->hook == list || zone_end < ext->start) {
  			/* New extent is necessary */
  			struct mem_extent *new_ext;
  
  			new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
  			if (!new_ext) {
  				free_mem_extents(list);
  				return -ENOMEM;
  			}
  			new_ext->start = zone_start;
  			new_ext->end = zone_end;
  			list_add_tail(&new_ext->hook, &ext->hook);
  			continue;
  		}
  
  		/* Merge this zone's range of PFNs with the existing one */
  		if (zone_start < ext->start)
  			ext->start = zone_start;
  		if (zone_end > ext->end)
  			ext->end = zone_end;
  
  		/* More merging may be possible */
  		cur = ext;
  		list_for_each_entry_safe_continue(cur, aux, list, hook) {
  			if (zone_end < cur->start)
  				break;
  			if (zone_end < cur->end)
  				ext->end = cur->end;
  			list_del(&cur->hook);
  			kfree(cur);
  		}

  	}

  
  	return 0;

  }
  
  /**
    *	memory_bm_create - allocate memory for a memory bitmap
    */

  static int
  memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
  {
  	struct chain_allocator ca;

  	struct list_head mem_extents;
  	struct mem_extent *ext;
  	int error;

  
  	chain_init(&ca, gfp_mask, safe_needed);

  	INIT_LIST_HEAD(&bm->blocks);

  	error = create_mem_extents(&mem_extents, gfp_mask);
  	if (error)
  		return error;

  	list_for_each_entry(ext, &mem_extents, hook) {
  		struct bm_block *bb;
  		unsigned long pfn = ext->start;
  		unsigned long pages = ext->end - ext->start;

  		bb = list_entry(bm->blocks.prev, struct bm_block, hook);

  		error = create_bm_block_list(pages, bm->blocks.prev, &ca);
  		if (error)
  			goto Error;

  		list_for_each_entry_continue(bb, &bm->blocks, hook) {
  			bb->data = get_image_page(gfp_mask, safe_needed);
  			if (!bb->data) {
  				error = -ENOMEM;
  				goto Error;
  			}

  
  			bb->start_pfn = pfn;

  			if (pages >= BM_BITS_PER_BLOCK) {

  				pfn += BM_BITS_PER_BLOCK;

  				pages -= BM_BITS_PER_BLOCK;

  			} else {
  				/* This is executed only once in the loop */

  				pfn += pages;

  			}
  			bb->end_pfn = pfn;

  		}

  	}

  	bm->p_list = ca.chain;
  	memory_bm_position_reset(bm);

   Exit:
  	free_mem_extents(&mem_extents);
  	return error;

   Error:

  	bm->p_list = ca.chain;
  	memory_bm_free(bm, PG_UNSAFE_CLEAR);

  	goto Exit;

  }
  
  /**
    *	memory_bm_free - free memory occupied by the memory bitmap @bm
    */

  static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
  {

  	struct bm_block *bb;

  	list_for_each_entry(bb, &bm->blocks, hook)
  		if (bb->data)
  			free_image_page(bb->data, clear_nosave_free);

  	free_list_of_pages(bm->p_list, clear_nosave_free);

  
  	INIT_LIST_HEAD(&bm->blocks);

  }
  
  /**

   *	memory_bm_find_bit - find the bit in the bitmap @bm that corresponds

   *	to given pfn.  The cur_zone_bm member of @bm and the cur_block member
   *	of @bm->cur_zone_bm are updated.

   */

  static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,

  				void **addr, unsigned int *bit_nr)

  {

  	struct bm_block *bb;

  	/*
  	 * Check if the pfn corresponds to the current bitmap block and find
  	 * the block where it fits if this is not the case.
  	 */
  	bb = bm->cur.block;

  	if (pfn < bb->start_pfn)

  		list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
  			if (pfn >= bb->start_pfn)
  				break;

  	if (pfn >= bb->end_pfn)
  		list_for_each_entry_continue(bb, &bm->blocks, hook)
  			if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
  				break;

  	if (&bb->hook == &bm->blocks)
  		return -EFAULT;
  
  	/* The block has been found */
  	bm->cur.block = bb;

  	pfn -= bb->start_pfn;

  	bm->cur.bit = pfn + 1;

  	*bit_nr = pfn;
  	*addr = bb->data;

  	return 0;

  }
  
  static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
  {
  	void *addr;
  	unsigned int bit;

  	int error;

  	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
  	BUG_ON(error);

  	set_bit(bit, addr);
  }

  static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
  {
  	void *addr;
  	unsigned int bit;
  	int error;
  
  	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
  	if (!error)
  		set_bit(bit, addr);
  	return error;
  }

  static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
  {
  	void *addr;
  	unsigned int bit;

  	int error;

  	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
  	BUG_ON(error);

  	clear_bit(bit, addr);
  }
  
  static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
  {
  	void *addr;
  	unsigned int bit;

  	int error;

  	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
  	BUG_ON(error);

  	return test_bit(bit, addr);

  }

  static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
  {
  	void *addr;
  	unsigned int bit;
  
  	return !memory_bm_find_bit(bm, pfn, &addr, &bit);
  }

  /**
   *	memory_bm_next_pfn - find the pfn that corresponds to the next set bit
   *	in the bitmap @bm.  If the pfn cannot be found, BM_END_OF_MAP is
   *	returned.
   *
   *	It is required to run memory_bm_position_reset() before the first call to
   *	this function.
   */
  
  static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
  {

  	struct bm_block *bb;

  	int bit;

  	bb = bm->cur.block;

  	do {

  		bit = bm->cur.bit;
  		bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
  		if (bit < bm_block_bits(bb))
  			goto Return_pfn;
  
  		bb = list_entry(bb->hook.next, struct bm_block, hook);
  		bm->cur.block = bb;
  		bm->cur.bit = 0;
  	} while (&bb->hook != &bm->blocks);

  	memory_bm_position_reset(bm);
  	return BM_END_OF_MAP;

   Return_pfn:

  	bm->cur.bit = bit + 1;
  	return bb->start_pfn + bit;

  }
  
  /**

   *	This structure represents a range of page frames the contents of which
   *	should not be saved during the suspend.
   */
  
  struct nosave_region {
  	struct list_head list;
  	unsigned long start_pfn;
  	unsigned long end_pfn;
  };
  
  static LIST_HEAD(nosave_regions);
  
  /**
   *	register_nosave_region - register a range of page frames the contents
   *	of which should not be saved during the suspend (to be used in the early
   *	initialization code)
   */
  
  void __init

  __register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
  			 int use_kmalloc)

  {
  	struct nosave_region *region;
  
  	if (start_pfn >= end_pfn)
  		return;
  
  	if (!list_empty(&nosave_regions)) {
  		/* Try to extend the previous region (they should be sorted) */
  		region = list_entry(nosave_regions.prev,
  					struct nosave_region, list);
  		if (region->end_pfn == start_pfn) {
  			region->end_pfn = end_pfn;
  			goto Report;
  		}
  	}

  	if (use_kmalloc) {
  		/* during init, this shouldn't fail */
  		region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
  		BUG_ON(!region);
  	} else
  		/* This allocation cannot fail */

  		region = alloc_bootmem(sizeof(struct nosave_region));

  	region->start_pfn = start_pfn;
  	region->end_pfn = end_pfn;
  	list_add_tail(&region->list, &nosave_regions);
   Report:

  	printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx
  ",

  		start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
  }
  
  /*
   * Set bits in this map correspond to the page frames the contents of which
   * should not be saved during the suspend.
   */
  static struct memory_bitmap *forbidden_pages_map;
  
  /* Set bits in this map correspond to free page frames. */
  static struct memory_bitmap *free_pages_map;
  
  /*
   * Each page frame allocated for creating the image is marked by setting the
   * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
   */
  
  void swsusp_set_page_free(struct page *page)
  {
  	if (free_pages_map)
  		memory_bm_set_bit(free_pages_map, page_to_pfn(page));
  }
  
  static int swsusp_page_is_free(struct page *page)
  {
  	return free_pages_map ?
  		memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
  }
  
  void swsusp_unset_page_free(struct page *page)
  {
  	if (free_pages_map)
  		memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
  }
  
  static void swsusp_set_page_forbidden(struct page *page)
  {
  	if (forbidden_pages_map)
  		memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
  }
  
  int swsusp_page_is_forbidden(struct page *page)
  {
  	return forbidden_pages_map ?
  		memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
  }
  
  static void swsusp_unset_page_forbidden(struct page *page)
  {
  	if (forbidden_pages_map)
  		memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
  }
  
  /**
   *	mark_nosave_pages - set bits corresponding to the page frames the
   *	contents of which should not be saved in a given bitmap.
   */
  
  static void mark_nosave_pages(struct memory_bitmap *bm)
  {
  	struct nosave_region *region;
  
  	if (list_empty(&nosave_regions))
  		return;
  
  	list_for_each_entry(region, &nosave_regions, list) {
  		unsigned long pfn;

  		pr_debug("PM: Marking nosave pages: %016lx - %016lx
  ",

  				region->start_pfn << PAGE_SHIFT,
  				region->end_pfn << PAGE_SHIFT);
  
  		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)

  			if (pfn_valid(pfn)) {
  				/*
  				 * It is safe to ignore the result of
  				 * mem_bm_set_bit_check() here, since we won't
  				 * touch the PFNs for which the error is
  				 * returned anyway.
  				 */
  				mem_bm_set_bit_check(bm, pfn);
  			}

  	}
  }
  
  /**
   *	create_basic_memory_bitmaps - create bitmaps needed for marking page
   *	frames that should not be saved and free page frames.  The pointers
   *	forbidden_pages_map and free_pages_map are only modified if everything
   *	goes well, because we don't want the bits to be used before both bitmaps
   *	are set up.
   */
  
  int create_basic_memory_bitmaps(void)
  {
  	struct memory_bitmap *bm1, *bm2;
  	int error = 0;
  
  	BUG_ON(forbidden_pages_map || free_pages_map);

  	bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);

  	if (!bm1)
  		return -ENOMEM;

  	error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);

  	if (error)
  		goto Free_first_object;

  	bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);

  	if (!bm2)
  		goto Free_first_bitmap;

  	error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);

  	if (error)
  		goto Free_second_object;
  
  	forbidden_pages_map = bm1;
  	free_pages_map = bm2;
  	mark_nosave_pages(forbidden_pages_map);

  	pr_debug("PM: Basic memory bitmaps created
  ");

  
  	return 0;
  
   Free_second_object:
  	kfree(bm2);
   Free_first_bitmap:
   	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
   Free_first_object:
  	kfree(bm1);
  	return -ENOMEM;
  }
  
  /**
   *	free_basic_memory_bitmaps - free memory bitmaps allocated by
   *	create_basic_memory_bitmaps().  The auxiliary pointers are necessary
   *	so that the bitmaps themselves are not referred to while they are being
   *	freed.
   */
  
  void free_basic_memory_bitmaps(void)
  {
  	struct memory_bitmap *bm1, *bm2;
  
  	BUG_ON(!(forbidden_pages_map && free_pages_map));
  
  	bm1 = forbidden_pages_map;
  	bm2 = free_pages_map;
  	forbidden_pages_map = NULL;
  	free_pages_map = NULL;
  	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
  	kfree(bm1);
  	memory_bm_free(bm2, PG_UNSAFE_CLEAR);
  	kfree(bm2);

  	pr_debug("PM: Basic memory bitmaps freed
  ");

  }
  
  /**

   *	snapshot_additional_pages - estimate the number of additional pages
   *	be needed for setting up the suspend image data structures for given
   *	zone (usually the returned value is greater than the exact number)
   */
  
  unsigned int snapshot_additional_pages(struct zone *zone)
  {
  	unsigned int res;
  
  	res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
  	res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);

  	return 2 * res;

  }

  #ifdef CONFIG_HIGHMEM
  /**
   *	count_free_highmem_pages - compute the total number of free highmem
   *	pages, system-wide.
   */
  
  static unsigned int count_free_highmem_pages(void)
  {
  	struct zone *zone;
  	unsigned int cnt = 0;

  	for_each_populated_zone(zone)
  		if (is_highmem(zone))

  			cnt += zone_page_state(zone, NR_FREE_PAGES);

  
  	return cnt;
  }
  
  /**
   *	saveable_highmem_page - Determine whether a highmem page should be
   *	included in the suspend image.
   *
   *	We should save the page if it isn't Nosave or NosaveFree, or Reserved,
   *	and it isn't a part of a free chunk of pages.
   */

  static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)

  {
  	struct page *page;
  
  	if (!pfn_valid(pfn))
  		return NULL;
  
  	page = pfn_to_page(pfn);

  	if (page_zone(page) != zone)
  		return NULL;

  
  	BUG_ON(!PageHighMem(page));

  	if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page) ||
  	    PageReserved(page))

  		return NULL;

  	if (page_is_guard(page))
  		return NULL;

  	return page;
  }
  
  /**
   *	count_highmem_pages - compute the total number of saveable highmem
   *	pages.
   */

  static unsigned int count_highmem_pages(void)

  {
  	struct zone *zone;
  	unsigned int n = 0;

  	for_each_populated_zone(zone) {

  		unsigned long pfn, max_zone_pfn;
  
  		if (!is_highmem(zone))
  			continue;
  
  		mark_free_pages(zone);
  		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
  		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)

  			if (saveable_highmem_page(zone, pfn))

  				n++;
  	}
  	return n;
  }
  #else

  static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
  {
  	return NULL;
  }

  #endif /* CONFIG_HIGHMEM */

  /**

   *	saveable_page - Determine whether a non-highmem page should be included
   *	in the suspend image.

   *

   *	We should save the page if it isn't Nosave, and is not in the range
   *	of pages statically defined as 'unsaveable', and it isn't a part of
   *	a free chunk of pages.

   */

  static struct page *saveable_page(struct zone *zone, unsigned long pfn)

  {

  	struct page *page;

  
  	if (!pfn_valid(pfn))

  		return NULL;

  
  	page = pfn_to_page(pfn);

  	if (page_zone(page) != zone)
  		return NULL;

  	BUG_ON(PageHighMem(page));

  	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))

  		return NULL;

  	if (PageReserved(page)
  	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))

  		return NULL;

  	if (page_is_guard(page))
  		return NULL;

  	return page;

  }

  /**
   *	count_data_pages - compute the total number of saveable non-highmem
   *	pages.
   */

  static unsigned int count_data_pages(void)

  {
  	struct zone *zone;

  	unsigned long pfn, max_zone_pfn;

  	unsigned int n = 0;

  	for_each_populated_zone(zone) {

  		if (is_highmem(zone))
  			continue;

  		mark_free_pages(zone);

  		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
  		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)

  			if (saveable_page(zone, pfn))

  				n++;

  	}

  	return n;

  }

  /* This is needed, because copy_page and memcpy are not usable for copying
   * task structs.
   */
  static inline void do_copy_page(long *dst, long *src)

  {
  	int n;

  	for (n = PAGE_SIZE / sizeof(long); n; n--)
  		*dst++ = *src++;
  }

  
  /**
   *	safe_copy_page - check if the page we are going to copy is marked as
   *		present in the kernel page tables (this always is the case if
   *		CONFIG_DEBUG_PAGEALLOC is not set and in that case
   *		kernel_page_present() always returns 'true').
   */
  static void safe_copy_page(void *dst, struct page *s_page)
  {
  	if (kernel_page_present(s_page)) {
  		do_copy_page(dst, page_address(s_page));
  	} else {
  		kernel_map_pages(s_page, 1, 1);
  		do_copy_page(dst, page_address(s_page));
  		kernel_map_pages(s_page, 1, 0);
  	}
  }

  #ifdef CONFIG_HIGHMEM
  static inline struct page *
  page_is_saveable(struct zone *zone, unsigned long pfn)
  {
  	return is_highmem(zone) ?

  		saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);

  }

  static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)

  {
  	struct page *s_page, *d_page;
  	void *src, *dst;
  
  	s_page = pfn_to_page(src_pfn);
  	d_page = pfn_to_page(dst_pfn);
  	if (PageHighMem(s_page)) {
  		src = kmap_atomic(s_page, KM_USER0);
  		dst = kmap_atomic(d_page, KM_USER1);
  		do_copy_page(dst, src);

  		kunmap_atomic(dst, KM_USER1);

  		kunmap_atomic(src, KM_USER0);

  	} else {

  		if (PageHighMem(d_page)) {
  			/* Page pointed to by src may contain some kernel
  			 * data modified by kmap_atomic()
  			 */

  			safe_copy_page(buffer, s_page);

  			dst = kmap_atomic(d_page, KM_USER0);

  			copy_page(dst, buffer);

  			kunmap_atomic(dst, KM_USER0);
  		} else {

  			safe_copy_page(page_address(d_page), s_page);

  		}
  	}
  }
  #else

  #define page_is_saveable(zone, pfn)	saveable_page(zone, pfn)

  static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)

  {

  	safe_copy_page(page_address(pfn_to_page(dst_pfn)),
  				pfn_to_page(src_pfn));

  }
  #endif /* CONFIG_HIGHMEM */

  static void
  copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)

  {
  	struct zone *zone;

  	unsigned long pfn;

  	for_each_populated_zone(zone) {

  		unsigned long max_zone_pfn;

  		mark_free_pages(zone);

  		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;

  		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)

  			if (page_is_saveable(zone, pfn))

  				memory_bm_set_bit(orig_bm, pfn);

  	}

  	memory_bm_position_reset(orig_bm);
  	memory_bm_position_reset(copy_bm);

  	for(;;) {

  		pfn = memory_bm_next_pfn(orig_bm);

  		if (unlikely(pfn == BM_END_OF_MAP))
  			break;
  		copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
  	}

  }

  /* Total number of image pages */
  static unsigned int nr_copy_pages;
  /* Number of pages needed for saving the original pfns of the image pages */
  static unsigned int nr_meta_pages;

  /*
   * Numbers of normal and highmem page frames allocated for hibernation image
   * before suspending devices.
   */
  unsigned int alloc_normal, alloc_highmem;
  /*
   * Memory bitmap used for marking saveable pages (during hibernation) or
   * hibernation image pages (during restore)
   */
  static struct memory_bitmap orig_bm;
  /*
   * Memory bitmap used during hibernation for marking allocated page frames that
   * will contain copies of saveable pages.  During restore it is initially used
   * for marking hibernation image pages, but then the set bits from it are
   * duplicated in @orig_bm and it is released.  On highmem systems it is next
   * used for marking "safe" highmem pages, but it has to be reinitialized for
   * this purpose.
   */
  static struct memory_bitmap copy_bm;

  /**

   *	swsusp_free - free pages allocated for the suspend.

   *

   *	Suspend pages are alocated before the atomic copy is made, so we
   *	need to release them after the resume.

   */
  
  void swsusp_free(void)
  {
  	struct zone *zone;

  	unsigned long pfn, max_zone_pfn;

  	for_each_populated_zone(zone) {

  		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
  		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
  			if (pfn_valid(pfn)) {
  				struct page *page = pfn_to_page(pfn);

  				if (swsusp_page_is_forbidden(page) &&
  				    swsusp_page_is_free(page)) {
  					swsusp_unset_page_forbidden(page);
  					swsusp_unset_page_free(page);

  					__free_page(page);

  				}
  			}
  	}

  	nr_copy_pages = 0;
  	nr_meta_pages = 0;

  	restore_pblist = NULL;

  	buffer = NULL;

  	alloc_normal = 0;
  	alloc_highmem = 0;

  }

  /* Helper functions used for the shrinking of memory. */
  
  #define GFP_IMAGE	(GFP_KERNEL | __GFP_NOWARN)

  /**

   * preallocate_image_pages - Allocate a number of pages for hibernation image
   * @nr_pages: Number of page frames to allocate.
   * @mask: GFP flags to use for the allocation.

   *

   * Return value: Number of page frames actually allocated
   */
  static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
  {
  	unsigned long nr_alloc = 0;
  
  	while (nr_pages > 0) {

  		struct page *page;
  
  		page = alloc_image_page(mask);
  		if (!page)

  			break;

  		memory_bm_set_bit(&copy_bm, page_to_pfn(page));
  		if (PageHighMem(page))
  			alloc_highmem++;
  		else
  			alloc_normal++;

  		nr_pages--;
  		nr_alloc++;
  	}
  
  	return nr_alloc;
  }

  static unsigned long preallocate_image_memory(unsigned long nr_pages,
  					      unsigned long avail_normal)

  {

  	unsigned long alloc;
  
  	if (avail_normal <= alloc_normal)
  		return 0;
  
  	alloc = avail_normal - alloc_normal;
  	if (nr_pages < alloc)
  		alloc = nr_pages;
  
  	return preallocate_image_pages(alloc, GFP_IMAGE);

  }
  
  #ifdef CONFIG_HIGHMEM
  static unsigned long preallocate_image_highmem(unsigned long nr_pages)
  {
  	return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
  }
  
  /**
   *  __fraction - Compute (an approximation of) x * (multiplier / base)

   */

  static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
  {
  	x *= multiplier;
  	do_div(x, base);
  	return (unsigned long)x;
  }

  static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
  						unsigned long highmem,
  						unsigned long total)

  {

  	unsigned long alloc = __fraction(nr_pages, highmem, total);
  
  	return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);

  }

  #else /* CONFIG_HIGHMEM */
  static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
  {
  	return 0;
  }
  
  static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
  						unsigned long highmem,
  						unsigned long total)
  {
  	return 0;
  }
  #endif /* CONFIG_HIGHMEM */

  /**

   * free_unnecessary_pages - Release preallocated pages not needed for the image
   */
  static void free_unnecessary_pages(void)
  {

  	unsigned long save, to_free_normal, to_free_highmem;

  	save = count_data_pages();
  	if (alloc_normal >= save) {
  		to_free_normal = alloc_normal - save;
  		save = 0;
  	} else {
  		to_free_normal = 0;
  		save -= alloc_normal;
  	}
  	save += count_highmem_pages();
  	if (alloc_highmem >= save) {
  		to_free_highmem = alloc_highmem - save;

  	} else {
  		to_free_highmem = 0;

  		save -= alloc_highmem;
  		if (to_free_normal > save)
  			to_free_normal -= save;
  		else
  			to_free_normal = 0;

  	}
  
  	memory_bm_position_reset(&copy_bm);

  	while (to_free_normal > 0 || to_free_highmem > 0) {

  		unsigned long pfn = memory_bm_next_pfn(&copy_bm);
  		struct page *page = pfn_to_page(pfn);
  
  		if (PageHighMem(page)) {
  			if (!to_free_highmem)
  				continue;
  			to_free_highmem--;
  			alloc_highmem--;
  		} else {
  			if (!to_free_normal)
  				continue;
  			to_free_normal--;
  			alloc_normal--;
  		}
  		memory_bm_clear_bit(&copy_bm, pfn);
  		swsusp_unset_page_forbidden(page);
  		swsusp_unset_page_free(page);
  		__free_page(page);
  	}
  }
  
  /**

   * minimum_image_size - Estimate the minimum acceptable size of an image
   * @saveable: Number of saveable pages in the system.
   *
   * We want to avoid attempting to free too much memory too hard, so estimate the
   * minimum acceptable size of a hibernation image to use as the lower limit for
   * preallocating memory.
   *
   * We assume that the minimum image size should be proportional to
   *
   * [number of saveable pages] - [number of pages that can be freed in theory]
   *
   * where the second term is the sum of (1) reclaimable slab pages, (2) active
   * and (3) inactive anonymouns pages, (4) active and (5) inactive file pages,
   * minus mapped file pages.
   */
  static unsigned long minimum_image_size(unsigned long saveable)
  {
  	unsigned long size;
  
  	size = global_page_state(NR_SLAB_RECLAIMABLE)
  		+ global_page_state(NR_ACTIVE_ANON)
  		+ global_page_state(NR_INACTIVE_ANON)
  		+ global_page_state(NR_ACTIVE_FILE)
  		+ global_page_state(NR_INACTIVE_FILE)
  		- global_page_state(NR_FILE_MAPPED);
  
  	return saveable <= size ? 0 : saveable - size;
  }
  
  /**

   * hibernate_preallocate_memory - Preallocate memory for hibernation image

   *
   * To create a hibernation image it is necessary to make a copy of every page
   * frame in use.  We also need a number of page frames to be free during
   * hibernation for allocations made while saving the image and for device
   * drivers, in case they need to allocate memory from their hibernation

   * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
   * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through
   * /sys/power/reserved_size, respectively).  To make this happen, we compute the
   * total number of available page frames and allocate at least

   *

   * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
   *  + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)

   *
   * of them, which corresponds to the maximum size of a hibernation image.
   *
   * If image_size is set below the number following from the above formula,
   * the preallocation of memory is continued until the total number of saveable

   * pages in the system is below the requested image size or the minimum
   * acceptable image size returned by minimum_image_size(), whichever is greater.

   */

  int hibernate_preallocate_memory(void)

  {

  	struct zone *zone;

  	unsigned long saveable, size, max_size, count, highmem, pages = 0;

  	unsigned long alloc, save_highmem, pages_highmem, avail_normal;

  	struct timeval start, stop;

  	int error;

  	printk(KERN_INFO "PM: Preallocating image memory... ");

  	do_gettimeofday(&start);

  	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
  	if (error)
  		goto err_out;
  
  	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
  	if (error)
  		goto err_out;
  
  	alloc_normal = 0;
  	alloc_highmem = 0;

  	/* Count the number of saveable data pages. */

  	save_highmem = count_highmem_pages();

  	saveable = count_data_pages();

  	/*
  	 * Compute the total number of page frames we can use (count) and the
  	 * number of pages needed for image metadata (size).
  	 */
  	count = saveable;

  	saveable += save_highmem;
  	highmem = save_highmem;

  	size = 0;
  	for_each_populated_zone(zone) {
  		size += snapshot_additional_pages(zone);
  		if (is_highmem(zone))
  			highmem += zone_page_state(zone, NR_FREE_PAGES);
  		else
  			count += zone_page_state(zone, NR_FREE_PAGES);
  	}

  	avail_normal = count;

  	count += highmem;
  	count -= totalreserve_pages;

  	/* Add number of pages required for page keys (s390 only). */
  	size += page_key_additional_pages(saveable);

  	/* Compute the maximum number of saveable pages to leave in memory. */

  	max_size = (count - (size + PAGES_FOR_IO)) / 2
  			- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);

  	/* Compute the desired number of image pages specified by image_size. */

  	size = DIV_ROUND_UP(image_size, PAGE_SIZE);
  	if (size > max_size)
  		size = max_size;
  	/*

  	 * If the desired number of image pages is at least as large as the
  	 * current number of saveable pages in memory, allocate page frames for
  	 * the image and we're done.

  	 */

  	if (size >= saveable) {
  		pages = preallocate_image_highmem(save_highmem);

  		pages += preallocate_image_memory(saveable - pages, avail_normal);

  		goto out;

  	}

  	/* Estimate the minimum size of the image. */
  	pages = minimum_image_size(saveable);

  	/*
  	 * To avoid excessive pressure on the normal zone, leave room in it to
  	 * accommodate an image of the minimum size (unless it's already too
  	 * small, in which case don't preallocate pages from it at all).
  	 */
  	if (avail_normal > pages)
  		avail_normal -= pages;
  	else
  		avail_normal = 0;

  	if (size < pages)
  		size = min_t(unsigned long, pages, max_size);

  	/*
  	 * Let the memory management subsystem know that we're going to need a
  	 * large number of page frames to allocate and make it free some memory.
  	 * NOTE: If this is not done, performance will be hurt badly in some
  	 * test cases.
  	 */
  	shrink_all_memory(saveable - size);
  
  	/*
  	 * The number of saveable pages in memory was too high, so apply some
  	 * pressure to decrease it.  First, make room for the largest possible
  	 * image and fail if that doesn't work.  Next, try to decrease the size

  	 * of the image as much as indicated by 'size' using allocations from
  	 * highmem and non-highmem zones separately.

  	 */
  	pages_highmem = preallocate_image_highmem(highmem / 2);
  	alloc = (count - max_size) - pages_highmem;

  	pages = preallocate_image_memory(alloc, avail_normal);
  	if (pages < alloc) {
  		/* We have exhausted non-highmem pages, try highmem. */
  		alloc -= pages;
  		pages += pages_highmem;
  		pages_highmem = preallocate_image_highmem(alloc);
  		if (pages_highmem < alloc)
  			goto err_out;
  		pages += pages_highmem;
  		/*
  		 * size is the desired number of saveable pages to leave in
  		 * memory, so try to preallocate (all memory - size) pages.
  		 */
  		alloc = (count - pages) - size;
  		pages += preallocate_image_highmem(alloc);
  	} else {
  		/*
  		 * There are approximately max_size saveable pages at this point
  		 * and we want to reduce this number down to size.
  		 */
  		alloc = max_size - size;
  		size = preallocate_highmem_fraction(alloc, highmem, count);
  		pages_highmem += size;
  		alloc -= size;
  		size = preallocate_image_memory(alloc, avail_normal);
  		pages_highmem += preallocate_image_highmem(alloc - size);
  		pages += pages_highmem + size;
  	}

  	/*
  	 * We only need as many page frames for the image as there are saveable
  	 * pages in memory, but we have allocated more.  Release the excessive
  	 * ones now.
  	 */
  	free_unnecessary_pages();

  
   out:

  	do_gettimeofday(&stop);

  	printk(KERN_CONT "done (allocated %lu pages)
  ", pages);
  	swsusp_show_speed(&start, &stop, pages, "Allocated");

  
  	return 0;

  
   err_out:
  	printk(KERN_CONT "
  ");
  	swsusp_free();
  	return -ENOMEM;

  }

  #ifdef CONFIG_HIGHMEM
  /**
    *	count_pages_for_highmem - compute the number of non-highmem pages
    *	that will be necessary for creating copies of highmem pages.
    */
  
  static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
  {

  	unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;

  
  	if (free_highmem >= nr_highmem)
  		nr_highmem = 0;
  	else
  		nr_highmem -= free_highmem;
  
  	return nr_highmem;
  }
  #else
  static unsigned int
  count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
  #endif /* CONFIG_HIGHMEM */

  
  /**

   *	enough_free_mem - Make sure we have enough free memory for the
   *	snapshot image.

   */

  static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)

  {

  	struct zone *zone;

  	unsigned int free = alloc_normal;

  	for_each_populated_zone(zone)

  		if (!is_highmem(zone))

  			free += zone_page_state(zone, NR_FREE_PAGES);

  	nr_pages += count_pages_for_highmem(nr_highmem);

  	pr_debug("PM: Normal pages needed: %u + %u, available pages: %u
  ",
  		nr_pages, PAGES_FOR_IO, free);

  	return free > nr_pages + PAGES_FOR_IO;

  }

  #ifdef CONFIG_HIGHMEM
  /**
   *	get_highmem_buffer - if there are some highmem pages in the suspend
   *	image, we may need the buffer to copy them and/or load their data.
   */
  
  static inline int get_highmem_buffer(int safe_needed)
  {
  	buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
  	return buffer ? 0 : -ENOMEM;
  }
  
  /**
   *	alloc_highmem_image_pages - allocate some highmem pages for the image.
   *	Try to allocate as many pages as needed, but if the number of free
   *	highmem pages is lesser than that, allocate them all.
   */
  
  static inline unsigned int

  alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem)

  {
  	unsigned int to_alloc = count_free_highmem_pages();
  
  	if (to_alloc > nr_highmem)
  		to_alloc = nr_highmem;
  
  	nr_highmem -= to_alloc;
  	while (to_alloc-- > 0) {
  		struct page *page;
  
  		page = alloc_image_page(__GFP_HIGHMEM);
  		memory_bm_set_bit(bm, page_to_pfn(page));
  	}
  	return nr_highmem;
  }
  #else
  static inline int get_highmem_buffer(int safe_needed) { return 0; }
  
  static inline unsigned int

  alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }

  #endif /* CONFIG_HIGHMEM */
  
  /**
   *	swsusp_alloc - allocate memory for the suspend image
   *
   *	We first try to allocate as many highmem pages as there are
   *	saveable highmem pages in the system.  If that fails, we allocate
   *	non-highmem pages for the copies of the remaining highmem ones.
   *
   *	In this approach it is likely that the copies of highmem pages will
   *	also be located in the high memory, because of the way in which
   *	copy_data_pages() works.
   */

  static int
  swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,

  		unsigned int nr_pages, unsigned int nr_highmem)

  {

  	if (nr_highmem > 0) {

  		if (get_highmem_buffer(PG_ANY))

  			goto err_out;
  		if (nr_highmem > alloc_highmem) {
  			nr_highmem -= alloc_highmem;
  			nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
  		}

  	}

  	if (nr_pages > alloc_normal) {
  		nr_pages -= alloc_normal;
  		while (nr_pages-- > 0) {
  			struct page *page;
  
  			page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
  			if (!page)
  				goto err_out;
  			memory_bm_set_bit(copy_bm, page_to_pfn(page));
  		}

  	}

  	return 0;

   err_out:

  	swsusp_free();

  	return -ENOMEM;

  }

  asmlinkage int swsusp_save(void)

  {

  	unsigned int nr_pages, nr_highmem;

  	printk(KERN_INFO "PM: Creating hibernation image:
  ");

  	drain_local_pages(NULL);

  	nr_pages = count_data_pages();

  	nr_highmem = count_highmem_pages();

  	printk(KERN_INFO "PM: Need to copy %u pages
  ", nr_pages + nr_highmem);

  	if (!enough_free_mem(nr_pages, nr_highmem)) {

  		printk(KERN_ERR "PM: Not enough free memory
  ");

  		return -ENOMEM;
  	}

  	if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages, nr_highmem)) {

  		printk(KERN_ERR "PM: Memory allocation failed
  ");

  		return -ENOMEM;

  	}

  
  	/* During allocating of suspend pagedir, new cold pages may appear.
  	 * Kill them.
  	 */

  	drain_local_pages(NULL);

  	copy_data_pages(&copy_bm, &orig_bm);

  
  	/*
  	 * End of critical section. From now on, we can write to memory,
  	 * but we should not touch disk. This specially means we must _not_
  	 * touch swap space! Except we must write out our image of course.
  	 */

  	nr_pages += nr_highmem;

  	nr_copy_pages = nr_pages;

  	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);

  	printk(KERN_INFO "PM: Hibernation image created (%d pages copied)
  ",
  		nr_pages);

  	return 0;
  }

  #ifndef CONFIG_ARCH_HIBERNATION_HEADER
  static int init_header_complete(struct swsusp_info *info)

  {

  	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));

  	info->version_code = LINUX_VERSION_CODE;

  	return 0;
  }
  
  static char *check_image_kernel(struct swsusp_info *info)
  {
  	if (info->version_code != LINUX_VERSION_CODE)
  		return "kernel version";
  	if (strcmp(info->uts.sysname,init_utsname()->sysname))
  		return "system type";
  	if (strcmp(info->uts.release,init_utsname()->release))
  		return "kernel release";
  	if (strcmp(info->uts.version,init_utsname()->version))
  		return "version";
  	if (strcmp(info->uts.machine,init_utsname()->machine))
  		return "machine";
  	return NULL;
  }
  #endif /* CONFIG_ARCH_HIBERNATION_HEADER */

  unsigned long snapshot_get_image_size(void)
  {
  	return nr_copy_pages + nr_meta_pages + 1;
  }

  static int init_header(struct swsusp_info *info)
  {
  	memset(info, 0, sizeof(struct swsusp_info));

  	info->num_physpages = num_physpages;

  	info->image_pages = nr_copy_pages;

  	info->pages = snapshot_get_image_size();

  	info->size = info->pages;
  	info->size <<= PAGE_SHIFT;

  	return init_header_complete(info);

  }
  
  /**

   *	pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
   *	are stored in the array @buf[] (1 page at a time)

   */

  static inline void

  pack_pfns(unsigned long *buf, struct memory_bitmap *bm)

  {
  	int j;

  	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {

  		buf[j] = memory_bm_next_pfn(bm);
  		if (unlikely(buf[j] == BM_END_OF_MAP))

  			break;

  		/* Save page key for data page (s390 only). */
  		page_key_read(buf + j);

  	}

  }
  
  /**
   *	snapshot_read_next - used for reading the system memory snapshot.
   *
   *	On the first call to it @handle should point to a zeroed
   *	snapshot_handle structure.  The structure gets updated and a pointer
   *	to it should be passed to this function every next time.
   *

   *	On success the function returns a positive number.  Then, the caller
   *	is allowed to read up to the returned number of bytes from the memory

   *	location computed by the data_of() macro.

   *
   *	The function returns 0 to indicate the end of data stream condition,
   *	and a negative number is returned on error.  In such cases the
   *	structure pointed to by @handle is not updated and should not be used
   *	any more.
   */

  int snapshot_read_next(struct snapshot_handle *handle)

  {

  	if (handle->cur > nr_meta_pages + nr_copy_pages)

  		return 0;

  	if (!buffer) {
  		/* This makes the buffer be freed by swsusp_free() */

  		buffer = get_image_page(GFP_ATOMIC, PG_ANY);

  		if (!buffer)
  			return -ENOMEM;
  	}

  	if (!handle->cur) {

  		int error;
  
  		error = init_header((struct swsusp_info *)buffer);
  		if (error)
  			return error;

  		handle->buffer = buffer;

  		memory_bm_position_reset(&orig_bm);
  		memory_bm_position_reset(&copy_bm);

  	} else if (handle->cur <= nr_meta_pages) {

  		clear_page(buffer);

  		pack_pfns(buffer, &orig_bm);
  	} else {
  		struct page *page;

  		page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
  		if (PageHighMem(page)) {
  			/* Highmem pages are copied to the buffer,
  			 * because we can't return with a kmapped
  			 * highmem page (we may not be called again).
  			 */
  			void *kaddr;

  			kaddr = kmap_atomic(page, KM_USER0);

  			copy_page(buffer, kaddr);

  			kunmap_atomic(kaddr, KM_USER0);
  			handle->buffer = buffer;
  		} else {
  			handle->buffer = page_address(page);

  		}

  	}

  	handle->cur++;
  	return PAGE_SIZE;

  }
  
  /**
   *	mark_unsafe_pages - mark the pages that cannot be used for storing
   *	the image during resume, because they conflict with the pages that
   *	had been used before suspend
   */

  static int mark_unsafe_pages(struct memory_bitmap *bm)

  {
  	struct zone *zone;

  	unsigned long pfn, max_zone_pfn;

  
  	/* Clear page flags */

  	for_each_populated_zone(zone) {

  		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
  		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
  			if (pfn_valid(pfn))

  				swsusp_unset_page_free(pfn_to_page(pfn));

  	}

  	/* Mark pages that correspond to the "original" pfns as "unsafe" */
  	memory_bm_position_reset(bm);
  	do {
  		pfn = memory_bm_next_pfn(bm);
  		if (likely(pfn != BM_END_OF_MAP)) {
  			if (likely(pfn_valid(pfn)))

  				swsusp_set_page_free(pfn_to_page(pfn));

  			else
  				return -EFAULT;
  		}
  	} while (pfn != BM_END_OF_MAP);

  	allocated_unsafe_pages = 0;

  	return 0;
  }

  static void
  duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)

  {

  	unsigned long pfn;
  
  	memory_bm_position_reset(src);
  	pfn = memory_bm_next_pfn(src);
  	while (pfn != BM_END_OF_MAP) {
  		memory_bm_set_bit(dst, pfn);
  		pfn = memory_bm_next_pfn(src);

  	}
  }

  static int check_header(struct swsusp_info *info)

  {

  	char *reason;

  	reason = check_image_kernel(info);
  	if (!reason && info->num_physpages != num_physpages)

  		reason = "memory size";

  	if (reason) {

  		printk(KERN_ERR "PM: Image mismatch: %s
  ", reason);

  		return -EPERM;
  	}
  	return 0;
  }
  
  /**
   *	load header - check the image header and copy data from it
   */

  static int
  load_header(struct swsusp_info *info)

  {
  	int error;

  	restore_pblist = NULL;

  	error = check_header(info);
  	if (!error) {

  		nr_copy_pages = info->image_pages;
  		nr_meta_pages = info->pages - info->image_pages - 1;
  	}
  	return error;
  }
  
  /**

   *	unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
   *	the corresponding bit in the memory bitmap @bm

   */

  static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)

  {
  	int j;

  	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
  		if (unlikely(buf[j] == BM_END_OF_MAP))
  			break;

  		/* Extract and buffer page key for data page (s390 only). */
  		page_key_memorize(buf + j);

  		if (memory_bm_pfn_present(bm, buf[j]))
  			memory_bm_set_bit(bm, buf[j]);
  		else
  			return -EFAULT;

  	}

  
  	return 0;

  }

  /* List of "safe" pages that may be used to store data loaded from the suspend
   * image
   */
  static struct linked_page *safe_pages_list;
  
  #ifdef CONFIG_HIGHMEM
  /* struct highmem_pbe is used for creating the list of highmem pages that
   * should be restored atomically during the resume from disk, because the page
   * frames they have occupied before the suspend are in use.
   */
  struct highmem_pbe {
  	struct page *copy_page;	/* data is here now */
  	struct page *orig_page;	/* data was here before the suspend */
  	struct highmem_pbe *next;
  };
  
  /* List of highmem PBEs needed for restoring the highmem pages that were
   * allocated before the suspend and included in the suspend image, but have
   * also been allocated by the "resume" kernel, so their contents cannot be
   * written directly to their "original" page frames.
   */
  static struct highmem_pbe *highmem_pblist;
  
  /**
   *	count_highmem_image_pages - compute the number of highmem pages in the
   *	suspend image.  The bits in the memory bitmap @bm that correspond to the
   *	image pages are assumed to be set.
   */
  
  static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
  {
  	unsigned long pfn;
  	unsigned int cnt = 0;
  
  	memory_bm_position_reset(bm);
  	pfn = memory_bm_next_pfn(bm);
  	while (pfn != BM_END_OF_MAP) {
  		if (PageHighMem(pfn_to_page(pfn)))
  			cnt++;
  
  		pfn = memory_bm_next_pfn(bm);
  	}
  	return cnt;
  }
  
  /**
   *	prepare_highmem_image - try to allocate as many highmem pages as
   *	there are highmem image pages (@nr_highmem_p points to the variable
   *	containing the number of highmem image pages).  The pages that are
   *	"safe" (ie. will not be overwritten when the suspend image is
   *	restored) have the corresponding bits set in @bm (it must be
   *	unitialized).
   *
   *	NOTE: This function should not be called if there are no highmem
   *	image pages.
   */
  
  static unsigned int safe_highmem_pages;
  
  static struct memory_bitmap *safe_highmem_bm;
  
  static int
  prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
  {
  	unsigned int to_alloc;
  
  	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
  		return -ENOMEM;
  
  	if (get_highmem_buffer(PG_SAFE))
  		return -ENOMEM;
  
  	to_alloc = count_free_highmem_pages();
  	if (to_alloc > *nr_highmem_p)
  		to_alloc = *nr_highmem_p;
  	else
  		*nr_highmem_p = to_alloc;
  
  	safe_highmem_pages = 0;
  	while (to_alloc-- > 0) {
  		struct page *page;
  
  		page = alloc_page(__GFP_HIGHMEM);

  		if (!swsusp_page_is_free(page)) {

  			/* The page is "safe", set its bit the bitmap */
  			memory_bm_set_bit(bm, page_to_pfn(page));
  			safe_highmem_pages++;
  		}
  		/* Mark the page as allocated */

  		swsusp_set_page_forbidden(page);
  		swsusp_set_page_free(page);

  	}
  	memory_bm_position_reset(bm);
  	safe_highmem_bm = bm;
  	return 0;
  }
  
  /**
   *	get_highmem_page_buffer - for given highmem image page find the buffer
   *	that suspend_write_next() should set for its caller to write to.
   *
   *	If the page is to be saved to its "original" page frame or a copy of
   *	the page is to be made in the highmem, @buffer is returned.  Otherwise,
   *	the copy of the page is to be made in normal memory, so the address of
   *	the copy is returned.
   *
   *	If @buffer is returned, the caller of suspend_write_next() will write
   *	the page's contents to @buffer, so they will have to be copied to the
   *	right location on the next call to suspend_write_next() and it is done
   *	with the help of copy_last_highmem_page().  For this purpose, if
   *	@buffer is returned, @last_highmem page is set to the page to which
   *	the data will have to be copied from @buffer.
   */
  
  static struct page *last_highmem_page;
  
  static void *
  get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
  {
  	struct highmem_pbe *pbe;
  	void *kaddr;

  	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {

  		/* We have allocated the "original" page frame and we can
  		 * use it directly to store the loaded page.
  		 */
  		last_highmem_page = page;
  		return buffer;
  	}
  	/* The "original" page frame has not been allocated and we have to
  	 * use a "safe" page frame to store the loaded page.
  	 */
  	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
  	if (!pbe) {
  		swsusp_free();

  		return ERR_PTR(-ENOMEM);

  	}
  	pbe->orig_page = page;
  	if (safe_highmem_pages > 0) {
  		struct page *tmp;
  
  		/* Copy of the page will be stored in high memory */
  		kaddr = buffer;
  		tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
  		safe_highmem_pages--;
  		last_highmem_page = tmp;
  		pbe->copy_page = tmp;
  	} else {
  		/* Copy of the page will be stored in normal memory */
  		kaddr = safe_pages_list;
  		safe_pages_list = safe_pages_list->next;
  		pbe->copy_page = virt_to_page(kaddr);
  	}
  	pbe->next = highmem_pblist;
  	highmem_pblist = pbe;
  	return kaddr;
  }
  
  /**
   *	copy_last_highmem_page - copy the contents of a highmem image from
   *	@buffer, where the caller of snapshot_write_next() has place them,
   *	to the right location represented by @last_highmem_page .
   */
  
  static void copy_last_highmem_page(void)
  {
  	if (last_highmem_page) {
  		void *dst;
  
  		dst = kmap_atomic(last_highmem_page, KM_USER0);

  		copy_page(dst, buffer);

  		kunmap_atomic(dst, KM_USER0);
  		last_highmem_page = NULL;
  	}
  }
  
  static inline int last_highmem_page_copied(void)
  {
  	return !last_highmem_page;
  }
  
  static inline void free_highmem_data(void)
  {
  	if (safe_highmem_bm)
  		memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
  
  	if (buffer)
  		free_image_page(buffer, PG_UNSAFE_CLEAR);
  }
  #else
  static inline int get_safe_write_buffer(void) { return 0; }
  
  static unsigned int
  count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
  
  static inline int
  prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
  {
  	return 0;
  }
  
  static inline void *
  get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
  {

  	return ERR_PTR(-EINVAL);

  }
  
  static inline void copy_last_highmem_page(void) {}
  static inline int last_highmem_page_copied(void) { return 1; }
  static inline void free_highmem_data(void) {}
  #endif /* CONFIG_HIGHMEM */

  /**

   *	prepare_image - use the memory bitmap @bm to mark the pages that will
   *	be overwritten in the process of restoring the system memory state
   *	from the suspend image ("unsafe" pages) and allocate memory for the
   *	image.

   *

   *	The idea is to allocate a new memory bitmap first and then allocate
   *	as many pages as needed for the image data, but not to assign these
   *	pages to specific tasks initially.  Instead, we just mark them as

   *	allocated and create a lists of "safe" pages that will be used
   *	later.  On systems with high memory a list of "safe" highmem pages is
   *	also created.

   */

  #define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))

  static int
  prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)

  {

  	unsigned int nr_pages, nr_highmem;

  	struct linked_page *sp_list, *lp;
  	int error;

  	/* If there is no highmem, the buffer will not be necessary */
  	free_image_page(buffer, PG_UNSAFE_CLEAR);
  	buffer = NULL;
  
  	nr_highmem = count_highmem_image_pages(bm);

  	error = mark_unsafe_pages(bm);
  	if (error)
  		goto Free;
  
  	error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
  	if (error)
  		goto Free;
  
  	duplicate_memory_bitmap(new_bm, bm);
  	memory_bm_free(bm, PG_UNSAFE_KEEP);

  	if (nr_highmem > 0) {
  		error = prepare_highmem_image(bm, &nr_highmem);
  		if (error)
  			goto Free;
  	}

  	/* Reserve some safe pages for potential later use.
  	 *
  	 * NOTE: This way we make sure there will be enough safe pages for the
  	 * chain_alloc() in get_buffer().  It is a bit wasteful, but
  	 * nr_copy_pages cannot be greater than 50% of the memory anyway.
  	 */
  	sp_list = NULL;
  	/* nr_copy_pages cannot be lesser than allocated_unsafe_pages */

  	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;

  	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
  	while (nr_pages > 0) {

  		lp = get_image_page(GFP_ATOMIC, PG_SAFE);

  		if (!lp) {

  			error = -ENOMEM;

  			goto Free;
  		}
  		lp->next = sp_list;
  		sp_list = lp;
  		nr_pages--;

  	}

  	/* Preallocate memory for the image */
  	safe_pages_list = NULL;

  	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;

  	while (nr_pages > 0) {
  		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
  		if (!lp) {
  			error = -ENOMEM;
  			goto Free;
  		}

  		if (!swsusp_page_is_free(virt_to_page(lp))) {

  			/* The page is "safe", add it to the list */
  			lp->next = safe_pages_list;
  			safe_pages_list = lp;

  		}

  		/* Mark the page as allocated */

  		swsusp_set_page_forbidden(virt_to_page(lp));
  		swsusp_set_page_free(virt_to_page(lp));

  		nr_pages--;

  	}

  	/* Free the reserved safe pages so that chain_alloc() can use them */
  	while (sp_list) {
  		lp = sp_list->next;
  		free_image_page(sp_list, PG_UNSAFE_CLEAR);
  		sp_list = lp;

  	}

  	return 0;

   Free:

  	swsusp_free();