Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6
[~shefty/rdma-dev.git] / kernel / power / snapshot.c
1 /*
2  * linux/kernel/power/snapshot.c
3  *
4  * This file provides system snapshot/restore functionality for swsusp.
5  *
6  * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
7  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
8  *
9  * This file is released under the GPLv2.
10  *
11  */
12
13 #include <linux/version.h>
14 #include <linux/module.h>
15 #include <linux/mm.h>
16 #include <linux/suspend.h>
17 #include <linux/delay.h>
18 #include <linux/bitops.h>
19 #include <linux/spinlock.h>
20 #include <linux/kernel.h>
21 #include <linux/pm.h>
22 #include <linux/device.h>
23 #include <linux/init.h>
24 #include <linux/bootmem.h>
25 #include <linux/syscalls.h>
26 #include <linux/console.h>
27 #include <linux/highmem.h>
28 #include <linux/list.h>
29 #include <linux/slab.h>
30
31 #include <asm/uaccess.h>
32 #include <asm/mmu_context.h>
33 #include <asm/pgtable.h>
34 #include <asm/tlbflush.h>
35 #include <asm/io.h>
36
37 #include "power.h"
38
39 static int swsusp_page_is_free(struct page *);
40 static void swsusp_set_page_forbidden(struct page *);
41 static void swsusp_unset_page_forbidden(struct page *);
42
43 /*
44  * Preferred image size in bytes (tunable via /sys/power/image_size).
45  * When it is set to N, swsusp will do its best to ensure the image
46  * size will not exceed N bytes, but if that is impossible, it will
47  * try to create the smallest image possible.
48  */
49 unsigned long image_size = 500 * 1024 * 1024;
50
51 /* List of PBEs needed for restoring the pages that were allocated before
52  * the suspend and included in the suspend image, but have also been
53  * allocated by the "resume" kernel, so their contents cannot be written
54  * directly to their "original" page frames.
55  */
56 struct pbe *restore_pblist;
57
58 /* Pointer to an auxiliary buffer (1 page) */
59 static void *buffer;
60
61 /**
62  *      @safe_needed - on resume, for storing the PBE list and the image,
63  *      we can only use memory pages that do not conflict with the pages
64  *      used before suspend.  The unsafe pages have PageNosaveFree set
65  *      and we count them using unsafe_pages.
66  *
67  *      Each allocated image page is marked as PageNosave and PageNosaveFree
68  *      so that swsusp_free() can release it.
69  */
70
71 #define PG_ANY          0
72 #define PG_SAFE         1
73 #define PG_UNSAFE_CLEAR 1
74 #define PG_UNSAFE_KEEP  0
75
76 static unsigned int allocated_unsafe_pages;
77
78 static void *get_image_page(gfp_t gfp_mask, int safe_needed)
79 {
80         void *res;
81
82         res = (void *)get_zeroed_page(gfp_mask);
83         if (safe_needed)
84                 while (res && swsusp_page_is_free(virt_to_page(res))) {
85                         /* The page is unsafe, mark it for swsusp_free() */
86                         swsusp_set_page_forbidden(virt_to_page(res));
87                         allocated_unsafe_pages++;
88                         res = (void *)get_zeroed_page(gfp_mask);
89                 }
90         if (res) {
91                 swsusp_set_page_forbidden(virt_to_page(res));
92                 swsusp_set_page_free(virt_to_page(res));
93         }
94         return res;
95 }
96
97 unsigned long get_safe_page(gfp_t gfp_mask)
98 {
99         return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
100 }
101
102 static struct page *alloc_image_page(gfp_t gfp_mask)
103 {
104         struct page *page;
105
106         page = alloc_page(gfp_mask);
107         if (page) {
108                 swsusp_set_page_forbidden(page);
109                 swsusp_set_page_free(page);
110         }
111         return page;
112 }
113
114 /**
115  *      free_image_page - free page represented by @addr, allocated with
116  *      get_image_page (page flags set by it must be cleared)
117  */
118
119 static inline void free_image_page(void *addr, int clear_nosave_free)
120 {
121         struct page *page;
122
123         BUG_ON(!virt_addr_valid(addr));
124
125         page = virt_to_page(addr);
126
127         swsusp_unset_page_forbidden(page);
128         if (clear_nosave_free)
129                 swsusp_unset_page_free(page);
130
131         __free_page(page);
132 }
133
134 /* struct linked_page is used to build chains of pages */
135
136 #define LINKED_PAGE_DATA_SIZE   (PAGE_SIZE - sizeof(void *))
137
138 struct linked_page {
139         struct linked_page *next;
140         char data[LINKED_PAGE_DATA_SIZE];
141 } __attribute__((packed));
142
143 static inline void
144 free_list_of_pages(struct linked_page *list, int clear_page_nosave)
145 {
146         while (list) {
147                 struct linked_page *lp = list->next;
148
149                 free_image_page(list, clear_page_nosave);
150                 list = lp;
151         }
152 }
153
154 /**
155   *     struct chain_allocator is used for allocating small objects out of
156   *     a linked list of pages called 'the chain'.
157   *
158   *     The chain grows each time when there is no room for a new object in
159   *     the current page.  The allocated objects cannot be freed individually.
160   *     It is only possible to free them all at once, by freeing the entire
161   *     chain.
162   *
163   *     NOTE: The chain allocator may be inefficient if the allocated objects
164   *     are not much smaller than PAGE_SIZE.
165   */
166
167 struct chain_allocator {
168         struct linked_page *chain;      /* the chain */
169         unsigned int used_space;        /* total size of objects allocated out
170                                          * of the current page
171                                          */
172         gfp_t gfp_mask;         /* mask for allocating pages */
173         int safe_needed;        /* if set, only "safe" pages are allocated */
174 };
175
176 static void
177 chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
178 {
179         ca->chain = NULL;
180         ca->used_space = LINKED_PAGE_DATA_SIZE;
181         ca->gfp_mask = gfp_mask;
182         ca->safe_needed = safe_needed;
183 }
184
185 static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
186 {
187         void *ret;
188
189         if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
190                 struct linked_page *lp;
191
192                 lp = get_image_page(ca->gfp_mask, ca->safe_needed);
193                 if (!lp)
194                         return NULL;
195
196                 lp->next = ca->chain;
197                 ca->chain = lp;
198                 ca->used_space = 0;
199         }
200         ret = ca->chain->data + ca->used_space;
201         ca->used_space += size;
202         return ret;
203 }
204
205 /**
206  *      Data types related to memory bitmaps.
207  *
208  *      Memory bitmap is a structure consiting of many linked lists of
209  *      objects.  The main list's elements are of type struct zone_bitmap
210  *      and each of them corresonds to one zone.  For each zone bitmap
211  *      object there is a list of objects of type struct bm_block that
212  *      represent each blocks of bitmap in which information is stored.
213  *
214  *      struct memory_bitmap contains a pointer to the main list of zone
215  *      bitmap objects, a struct bm_position used for browsing the bitmap,
216  *      and a pointer to the list of pages used for allocating all of the
217  *      zone bitmap objects and bitmap block objects.
218  *
219  *      NOTE: It has to be possible to lay out the bitmap in memory
220  *      using only allocations of order 0.  Additionally, the bitmap is
221  *      designed to work with arbitrary number of zones (this is over the
222  *      top for now, but let's avoid making unnecessary assumptions ;-).
223  *
224  *      struct zone_bitmap contains a pointer to a list of bitmap block
225  *      objects and a pointer to the bitmap block object that has been
226  *      most recently used for setting bits.  Additionally, it contains the
227  *      pfns that correspond to the start and end of the represented zone.
228  *
229  *      struct bm_block contains a pointer to the memory page in which
230  *      information is stored (in the form of a block of bitmap)
231  *      It also contains the pfns that correspond to the start and end of
232  *      the represented memory area.
233  */
234
235 #define BM_END_OF_MAP   (~0UL)
236
237 #define BM_BITS_PER_BLOCK       (PAGE_SIZE * BITS_PER_BYTE)
238
239 struct bm_block {
240         struct list_head hook;  /* hook into a list of bitmap blocks */
241         unsigned long start_pfn;        /* pfn represented by the first bit */
242         unsigned long end_pfn;  /* pfn represented by the last bit plus 1 */
243         unsigned long *data;    /* bitmap representing pages */
244 };
245
246 static inline unsigned long bm_block_bits(struct bm_block *bb)
247 {
248         return bb->end_pfn - bb->start_pfn;
249 }
250
251 /* strcut bm_position is used for browsing memory bitmaps */
252
253 struct bm_position {
254         struct bm_block *block;
255         int bit;
256 };
257
258 struct memory_bitmap {
259         struct list_head blocks;        /* list of bitmap blocks */
260         struct linked_page *p_list;     /* list of pages used to store zone
261                                          * bitmap objects and bitmap block
262                                          * objects
263                                          */
264         struct bm_position cur; /* most recently used bit position */
265 };
266
267 /* Functions that operate on memory bitmaps */
268
269 static void memory_bm_position_reset(struct memory_bitmap *bm)
270 {
271         bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
272         bm->cur.bit = 0;
273 }
274
275 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
276
277 /**
278  *      create_bm_block_list - create a list of block bitmap objects
279  *      @pages - number of pages to track
280  *      @list - list to put the allocated blocks into
281  *      @ca - chain allocator to be used for allocating memory
282  */
283 static int create_bm_block_list(unsigned long pages,
284                                 struct list_head *list,
285                                 struct chain_allocator *ca)
286 {
287         unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
288
289         while (nr_blocks-- > 0) {
290                 struct bm_block *bb;
291
292                 bb = chain_alloc(ca, sizeof(struct bm_block));
293                 if (!bb)
294                         return -ENOMEM;
295                 list_add(&bb->hook, list);
296         }
297
298         return 0;
299 }
300
301 struct mem_extent {
302         struct list_head hook;
303         unsigned long start;
304         unsigned long end;
305 };
306
307 /**
308  *      free_mem_extents - free a list of memory extents
309  *      @list - list of extents to empty
310  */
311 static void free_mem_extents(struct list_head *list)
312 {
313         struct mem_extent *ext, *aux;
314
315         list_for_each_entry_safe(ext, aux, list, hook) {
316                 list_del(&ext->hook);
317                 kfree(ext);
318         }
319 }
320
321 /**
322  *      create_mem_extents - create a list of memory extents representing
323  *                           contiguous ranges of PFNs
324  *      @list - list to put the extents into
325  *      @gfp_mask - mask to use for memory allocations
326  */
327 static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
328 {
329         struct zone *zone;
330
331         INIT_LIST_HEAD(list);
332
333         for_each_populated_zone(zone) {
334                 unsigned long zone_start, zone_end;
335                 struct mem_extent *ext, *cur, *aux;
336
337                 zone_start = zone->zone_start_pfn;
338                 zone_end = zone->zone_start_pfn + zone->spanned_pages;
339
340                 list_for_each_entry(ext, list, hook)
341                         if (zone_start <= ext->end)
342                                 break;
343
344                 if (&ext->hook == list || zone_end < ext->start) {
345                         /* New extent is necessary */
346                         struct mem_extent *new_ext;
347
348                         new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
349                         if (!new_ext) {
350                                 free_mem_extents(list);
351                                 return -ENOMEM;
352                         }
353                         new_ext->start = zone_start;
354                         new_ext->end = zone_end;
355                         list_add_tail(&new_ext->hook, &ext->hook);
356                         continue;
357                 }
358
359                 /* Merge this zone's range of PFNs with the existing one */
360                 if (zone_start < ext->start)
361                         ext->start = zone_start;
362                 if (zone_end > ext->end)
363                         ext->end = zone_end;
364
365                 /* More merging may be possible */
366                 cur = ext;
367                 list_for_each_entry_safe_continue(cur, aux, list, hook) {
368                         if (zone_end < cur->start)
369                                 break;
370                         if (zone_end < cur->end)
371                                 ext->end = cur->end;
372                         list_del(&cur->hook);
373                         kfree(cur);
374                 }
375         }
376
377         return 0;
378 }
379
380 /**
381   *     memory_bm_create - allocate memory for a memory bitmap
382   */
383 static int
384 memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
385 {
386         struct chain_allocator ca;
387         struct list_head mem_extents;
388         struct mem_extent *ext;
389         int error;
390
391         chain_init(&ca, gfp_mask, safe_needed);
392         INIT_LIST_HEAD(&bm->blocks);
393
394         error = create_mem_extents(&mem_extents, gfp_mask);
395         if (error)
396                 return error;
397
398         list_for_each_entry(ext, &mem_extents, hook) {
399                 struct bm_block *bb;
400                 unsigned long pfn = ext->start;
401                 unsigned long pages = ext->end - ext->start;
402
403                 bb = list_entry(bm->blocks.prev, struct bm_block, hook);
404
405                 error = create_bm_block_list(pages, bm->blocks.prev, &ca);
406                 if (error)
407                         goto Error;
408
409                 list_for_each_entry_continue(bb, &bm->blocks, hook) {
410                         bb->data = get_image_page(gfp_mask, safe_needed);
411                         if (!bb->data) {
412                                 error = -ENOMEM;
413                                 goto Error;
414                         }
415
416                         bb->start_pfn = pfn;
417                         if (pages >= BM_BITS_PER_BLOCK) {
418                                 pfn += BM_BITS_PER_BLOCK;
419                                 pages -= BM_BITS_PER_BLOCK;
420                         } else {
421                                 /* This is executed only once in the loop */
422                                 pfn += pages;
423                         }
424                         bb->end_pfn = pfn;
425                 }
426         }
427
428         bm->p_list = ca.chain;
429         memory_bm_position_reset(bm);
430  Exit:
431         free_mem_extents(&mem_extents);
432         return error;
433
434  Error:
435         bm->p_list = ca.chain;
436         memory_bm_free(bm, PG_UNSAFE_CLEAR);
437         goto Exit;
438 }
439
440 /**
441   *     memory_bm_free - free memory occupied by the memory bitmap @bm
442   */
443 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
444 {
445         struct bm_block *bb;
446
447         list_for_each_entry(bb, &bm->blocks, hook)
448                 if (bb->data)
449                         free_image_page(bb->data, clear_nosave_free);
450
451         free_list_of_pages(bm->p_list, clear_nosave_free);
452
453         INIT_LIST_HEAD(&bm->blocks);
454 }
455
456 /**
457  *      memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
458  *      to given pfn.  The cur_zone_bm member of @bm and the cur_block member
459  *      of @bm->cur_zone_bm are updated.
460  */
461 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
462                                 void **addr, unsigned int *bit_nr)
463 {
464         struct bm_block *bb;
465
466         /*
467          * Check if the pfn corresponds to the current bitmap block and find
468          * the block where it fits if this is not the case.
469          */
470         bb = bm->cur.block;
471         if (pfn < bb->start_pfn)
472                 list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
473                         if (pfn >= bb->start_pfn)
474                                 break;
475
476         if (pfn >= bb->end_pfn)
477                 list_for_each_entry_continue(bb, &bm->blocks, hook)
478                         if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
479                                 break;
480
481         if (&bb->hook == &bm->blocks)
482                 return -EFAULT;
483
484         /* The block has been found */
485         bm->cur.block = bb;
486         pfn -= bb->start_pfn;
487         bm->cur.bit = pfn + 1;
488         *bit_nr = pfn;
489         *addr = bb->data;
490         return 0;
491 }
492
493 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
494 {
495         void *addr;
496         unsigned int bit;
497         int error;
498
499         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
500         BUG_ON(error);
501         set_bit(bit, addr);
502 }
503
504 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
505 {
506         void *addr;
507         unsigned int bit;
508         int error;
509
510         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
511         if (!error)
512                 set_bit(bit, addr);
513         return error;
514 }
515
516 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
517 {
518         void *addr;
519         unsigned int bit;
520         int error;
521
522         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
523         BUG_ON(error);
524         clear_bit(bit, addr);
525 }
526
527 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
528 {
529         void *addr;
530         unsigned int bit;
531         int error;
532
533         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
534         BUG_ON(error);
535         return test_bit(bit, addr);
536 }
537
538 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
539 {
540         void *addr;
541         unsigned int bit;
542
543         return !memory_bm_find_bit(bm, pfn, &addr, &bit);
544 }
545
546 /**
547  *      memory_bm_next_pfn - find the pfn that corresponds to the next set bit
548  *      in the bitmap @bm.  If the pfn cannot be found, BM_END_OF_MAP is
549  *      returned.
550  *
551  *      It is required to run memory_bm_position_reset() before the first call to
552  *      this function.
553  */
554
555 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
556 {
557         struct bm_block *bb;
558         int bit;
559
560         bb = bm->cur.block;
561         do {
562                 bit = bm->cur.bit;
563                 bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
564                 if (bit < bm_block_bits(bb))
565                         goto Return_pfn;
566
567                 bb = list_entry(bb->hook.next, struct bm_block, hook);
568                 bm->cur.block = bb;
569                 bm->cur.bit = 0;
570         } while (&bb->hook != &bm->blocks);
571
572         memory_bm_position_reset(bm);
573         return BM_END_OF_MAP;
574
575  Return_pfn:
576         bm->cur.bit = bit + 1;
577         return bb->start_pfn + bit;
578 }
579
580 /**
581  *      This structure represents a range of page frames the contents of which
582  *      should not be saved during the suspend.
583  */
584
585 struct nosave_region {
586         struct list_head list;
587         unsigned long start_pfn;
588         unsigned long end_pfn;
589 };
590
591 static LIST_HEAD(nosave_regions);
592
593 /**
594  *      register_nosave_region - register a range of page frames the contents
595  *      of which should not be saved during the suspend (to be used in the early
596  *      initialization code)
597  */
598
599 void __init
600 __register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
601                          int use_kmalloc)
602 {
603         struct nosave_region *region;
604
605         if (start_pfn >= end_pfn)
606                 return;
607
608         if (!list_empty(&nosave_regions)) {
609                 /* Try to extend the previous region (they should be sorted) */
610                 region = list_entry(nosave_regions.prev,
611                                         struct nosave_region, list);
612                 if (region->end_pfn == start_pfn) {
613                         region->end_pfn = end_pfn;
614                         goto Report;
615                 }
616         }
617         if (use_kmalloc) {
618                 /* during init, this shouldn't fail */
619                 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
620                 BUG_ON(!region);
621         } else
622                 /* This allocation cannot fail */
623                 region = alloc_bootmem(sizeof(struct nosave_region));
624         region->start_pfn = start_pfn;
625         region->end_pfn = end_pfn;
626         list_add_tail(&region->list, &nosave_regions);
627  Report:
628         printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n",
629                 start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
630 }
631
632 /*
633  * Set bits in this map correspond to the page frames the contents of which
634  * should not be saved during the suspend.
635  */
636 static struct memory_bitmap *forbidden_pages_map;
637
638 /* Set bits in this map correspond to free page frames. */
639 static struct memory_bitmap *free_pages_map;
640
641 /*
642  * Each page frame allocated for creating the image is marked by setting the
643  * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
644  */
645
646 void swsusp_set_page_free(struct page *page)
647 {
648         if (free_pages_map)
649                 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
650 }
651
652 static int swsusp_page_is_free(struct page *page)
653 {
654         return free_pages_map ?
655                 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
656 }
657
658 void swsusp_unset_page_free(struct page *page)
659 {
660         if (free_pages_map)
661                 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
662 }
663
664 static void swsusp_set_page_forbidden(struct page *page)
665 {
666         if (forbidden_pages_map)
667                 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
668 }
669
670 int swsusp_page_is_forbidden(struct page *page)
671 {
672         return forbidden_pages_map ?
673                 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
674 }
675
676 static void swsusp_unset_page_forbidden(struct page *page)
677 {
678         if (forbidden_pages_map)
679                 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
680 }
681
682 /**
683  *      mark_nosave_pages - set bits corresponding to the page frames the
684  *      contents of which should not be saved in a given bitmap.
685  */
686
687 static void mark_nosave_pages(struct memory_bitmap *bm)
688 {
689         struct nosave_region *region;
690
691         if (list_empty(&nosave_regions))
692                 return;
693
694         list_for_each_entry(region, &nosave_regions, list) {
695                 unsigned long pfn;
696
697                 pr_debug("PM: Marking nosave pages: %016lx - %016lx\n",
698                                 region->start_pfn << PAGE_SHIFT,
699                                 region->end_pfn << PAGE_SHIFT);
700
701                 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
702                         if (pfn_valid(pfn)) {
703                                 /*
704                                  * It is safe to ignore the result of
705                                  * mem_bm_set_bit_check() here, since we won't
706                                  * touch the PFNs for which the error is
707                                  * returned anyway.
708                                  */
709                                 mem_bm_set_bit_check(bm, pfn);
710                         }
711         }
712 }
713
714 /**
715  *      create_basic_memory_bitmaps - create bitmaps needed for marking page
716  *      frames that should not be saved and free page frames.  The pointers
717  *      forbidden_pages_map and free_pages_map are only modified if everything
718  *      goes well, because we don't want the bits to be used before both bitmaps
719  *      are set up.
720  */
721
722 int create_basic_memory_bitmaps(void)
723 {
724         struct memory_bitmap *bm1, *bm2;
725         int error = 0;
726
727         BUG_ON(forbidden_pages_map || free_pages_map);
728
729         bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
730         if (!bm1)
731                 return -ENOMEM;
732
733         error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
734         if (error)
735                 goto Free_first_object;
736
737         bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
738         if (!bm2)
739                 goto Free_first_bitmap;
740
741         error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
742         if (error)
743                 goto Free_second_object;
744
745         forbidden_pages_map = bm1;
746         free_pages_map = bm2;
747         mark_nosave_pages(forbidden_pages_map);
748
749         pr_debug("PM: Basic memory bitmaps created\n");
750
751         return 0;
752
753  Free_second_object:
754         kfree(bm2);
755  Free_first_bitmap:
756         memory_bm_free(bm1, PG_UNSAFE_CLEAR);
757  Free_first_object:
758         kfree(bm1);
759         return -ENOMEM;
760 }
761
762 /**
763  *      free_basic_memory_bitmaps - free memory bitmaps allocated by
764  *      create_basic_memory_bitmaps().  The auxiliary pointers are necessary
765  *      so that the bitmaps themselves are not referred to while they are being
766  *      freed.
767  */
768
769 void free_basic_memory_bitmaps(void)
770 {
771         struct memory_bitmap *bm1, *bm2;
772
773         BUG_ON(!(forbidden_pages_map && free_pages_map));
774
775         bm1 = forbidden_pages_map;
776         bm2 = free_pages_map;
777         forbidden_pages_map = NULL;
778         free_pages_map = NULL;
779         memory_bm_free(bm1, PG_UNSAFE_CLEAR);
780         kfree(bm1);
781         memory_bm_free(bm2, PG_UNSAFE_CLEAR);
782         kfree(bm2);
783
784         pr_debug("PM: Basic memory bitmaps freed\n");
785 }
786
787 /**
788  *      snapshot_additional_pages - estimate the number of additional pages
789  *      be needed for setting up the suspend image data structures for given
790  *      zone (usually the returned value is greater than the exact number)
791  */
792
793 unsigned int snapshot_additional_pages(struct zone *zone)
794 {
795         unsigned int res;
796
797         res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
798         res += DIV_ROUND_UP(res * sizeof(struct bm_block), PAGE_SIZE);
799         return 2 * res;
800 }
801
802 #ifdef CONFIG_HIGHMEM
803 /**
804  *      count_free_highmem_pages - compute the total number of free highmem
805  *      pages, system-wide.
806  */
807
808 static unsigned int count_free_highmem_pages(void)
809 {
810         struct zone *zone;
811         unsigned int cnt = 0;
812
813         for_each_populated_zone(zone)
814                 if (is_highmem(zone))
815                         cnt += zone_page_state(zone, NR_FREE_PAGES);
816
817         return cnt;
818 }
819
820 /**
821  *      saveable_highmem_page - Determine whether a highmem page should be
822  *      included in the suspend image.
823  *
824  *      We should save the page if it isn't Nosave or NosaveFree, or Reserved,
825  *      and it isn't a part of a free chunk of pages.
826  */
827 static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
828 {
829         struct page *page;
830
831         if (!pfn_valid(pfn))
832                 return NULL;
833
834         page = pfn_to_page(pfn);
835         if (page_zone(page) != zone)
836                 return NULL;
837
838         BUG_ON(!PageHighMem(page));
839
840         if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page) ||
841             PageReserved(page))
842                 return NULL;
843
844         return page;
845 }
846
847 /**
848  *      count_highmem_pages - compute the total number of saveable highmem
849  *      pages.
850  */
851
852 static unsigned int count_highmem_pages(void)
853 {
854         struct zone *zone;
855         unsigned int n = 0;
856
857         for_each_populated_zone(zone) {
858                 unsigned long pfn, max_zone_pfn;
859
860                 if (!is_highmem(zone))
861                         continue;
862
863                 mark_free_pages(zone);
864                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
865                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
866                         if (saveable_highmem_page(zone, pfn))
867                                 n++;
868         }
869         return n;
870 }
871 #else
872 static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
873 {
874         return NULL;
875 }
876 #endif /* CONFIG_HIGHMEM */
877
878 /**
879  *      saveable_page - Determine whether a non-highmem page should be included
880  *      in the suspend image.
881  *
882  *      We should save the page if it isn't Nosave, and is not in the range
883  *      of pages statically defined as 'unsaveable', and it isn't a part of
884  *      a free chunk of pages.
885  */
886 static struct page *saveable_page(struct zone *zone, unsigned long pfn)
887 {
888         struct page *page;
889
890         if (!pfn_valid(pfn))
891                 return NULL;
892
893         page = pfn_to_page(pfn);
894         if (page_zone(page) != zone)
895                 return NULL;
896
897         BUG_ON(PageHighMem(page));
898
899         if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
900                 return NULL;
901
902         if (PageReserved(page)
903             && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
904                 return NULL;
905
906         return page;
907 }
908
909 /**
910  *      count_data_pages - compute the total number of saveable non-highmem
911  *      pages.
912  */
913
914 static unsigned int count_data_pages(void)
915 {
916         struct zone *zone;
917         unsigned long pfn, max_zone_pfn;
918         unsigned int n = 0;
919
920         for_each_populated_zone(zone) {
921                 if (is_highmem(zone))
922                         continue;
923
924                 mark_free_pages(zone);
925                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
926                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
927                         if (saveable_page(zone, pfn))
928                                 n++;
929         }
930         return n;
931 }
932
933 /* This is needed, because copy_page and memcpy are not usable for copying
934  * task structs.
935  */
936 static inline void do_copy_page(long *dst, long *src)
937 {
938         int n;
939
940         for (n = PAGE_SIZE / sizeof(long); n; n--)
941                 *dst++ = *src++;
942 }
943
944
945 /**
946  *      safe_copy_page - check if the page we are going to copy is marked as
947  *              present in the kernel page tables (this always is the case if
948  *              CONFIG_DEBUG_PAGEALLOC is not set and in that case
949  *              kernel_page_present() always returns 'true').
950  */
951 static void safe_copy_page(void *dst, struct page *s_page)
952 {
953         if (kernel_page_present(s_page)) {
954                 do_copy_page(dst, page_address(s_page));
955         } else {
956                 kernel_map_pages(s_page, 1, 1);
957                 do_copy_page(dst, page_address(s_page));
958                 kernel_map_pages(s_page, 1, 0);
959         }
960 }
961
962
963 #ifdef CONFIG_HIGHMEM
964 static inline struct page *
965 page_is_saveable(struct zone *zone, unsigned long pfn)
966 {
967         return is_highmem(zone) ?
968                 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
969 }
970
971 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
972 {
973         struct page *s_page, *d_page;
974         void *src, *dst;
975
976         s_page = pfn_to_page(src_pfn);
977         d_page = pfn_to_page(dst_pfn);
978         if (PageHighMem(s_page)) {
979                 src = kmap_atomic(s_page, KM_USER0);
980                 dst = kmap_atomic(d_page, KM_USER1);
981                 do_copy_page(dst, src);
982                 kunmap_atomic(src, KM_USER0);
983                 kunmap_atomic(dst, KM_USER1);
984         } else {
985                 if (PageHighMem(d_page)) {
986                         /* Page pointed to by src may contain some kernel
987                          * data modified by kmap_atomic()
988                          */
989                         safe_copy_page(buffer, s_page);
990                         dst = kmap_atomic(d_page, KM_USER0);
991                         memcpy(dst, buffer, PAGE_SIZE);
992                         kunmap_atomic(dst, KM_USER0);
993                 } else {
994                         safe_copy_page(page_address(d_page), s_page);
995                 }
996         }
997 }
998 #else
999 #define page_is_saveable(zone, pfn)     saveable_page(zone, pfn)
1000
1001 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1002 {
1003         safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1004                                 pfn_to_page(src_pfn));
1005 }
1006 #endif /* CONFIG_HIGHMEM */
1007
1008 static void
1009 copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
1010 {
1011         struct zone *zone;
1012         unsigned long pfn;
1013
1014         for_each_populated_zone(zone) {
1015                 unsigned long max_zone_pfn;
1016
1017                 mark_free_pages(zone);
1018                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1019                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1020                         if (page_is_saveable(zone, pfn))
1021                                 memory_bm_set_bit(orig_bm, pfn);
1022         }
1023         memory_bm_position_reset(orig_bm);
1024         memory_bm_position_reset(copy_bm);
1025         for(;;) {
1026                 pfn = memory_bm_next_pfn(orig_bm);
1027                 if (unlikely(pfn == BM_END_OF_MAP))
1028                         break;
1029                 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1030         }
1031 }
1032
1033 /* Total number of image pages */
1034 static unsigned int nr_copy_pages;
1035 /* Number of pages needed for saving the original pfns of the image pages */
1036 static unsigned int nr_meta_pages;
1037 /*
1038  * Numbers of normal and highmem page frames allocated for hibernation image
1039  * before suspending devices.
1040  */
1041 unsigned int alloc_normal, alloc_highmem;
1042 /*
1043  * Memory bitmap used for marking saveable pages (during hibernation) or
1044  * hibernation image pages (during restore)
1045  */
1046 static struct memory_bitmap orig_bm;
1047 /*
1048  * Memory bitmap used during hibernation for marking allocated page frames that
1049  * will contain copies of saveable pages.  During restore it is initially used
1050  * for marking hibernation image pages, but then the set bits from it are
1051  * duplicated in @orig_bm and it is released.  On highmem systems it is next
1052  * used for marking "safe" highmem pages, but it has to be reinitialized for
1053  * this purpose.
1054  */
1055 static struct memory_bitmap copy_bm;
1056
1057 /**
1058  *      swsusp_free - free pages allocated for the suspend.
1059  *
1060  *      Suspend pages are alocated before the atomic copy is made, so we
1061  *      need to release them after the resume.
1062  */
1063
1064 void swsusp_free(void)
1065 {
1066         struct zone *zone;
1067         unsigned long pfn, max_zone_pfn;
1068
1069         for_each_populated_zone(zone) {
1070                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1071                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1072                         if (pfn_valid(pfn)) {
1073                                 struct page *page = pfn_to_page(pfn);
1074
1075                                 if (swsusp_page_is_forbidden(page) &&
1076                                     swsusp_page_is_free(page)) {
1077                                         swsusp_unset_page_forbidden(page);
1078                                         swsusp_unset_page_free(page);
1079                                         __free_page(page);
1080                                 }
1081                         }
1082         }
1083         nr_copy_pages = 0;
1084         nr_meta_pages = 0;
1085         restore_pblist = NULL;
1086         buffer = NULL;
1087         alloc_normal = 0;
1088         alloc_highmem = 0;
1089 }
1090
1091 /* Helper functions used for the shrinking of memory. */
1092
1093 #define GFP_IMAGE       (GFP_KERNEL | __GFP_NOWARN)
1094
1095 /**
1096  * preallocate_image_pages - Allocate a number of pages for hibernation image
1097  * @nr_pages: Number of page frames to allocate.
1098  * @mask: GFP flags to use for the allocation.
1099  *
1100  * Return value: Number of page frames actually allocated
1101  */
1102 static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1103 {
1104         unsigned long nr_alloc = 0;
1105
1106         while (nr_pages > 0) {
1107                 struct page *page;
1108
1109                 page = alloc_image_page(mask);
1110                 if (!page)
1111                         break;
1112                 memory_bm_set_bit(&copy_bm, page_to_pfn(page));
1113                 if (PageHighMem(page))
1114                         alloc_highmem++;
1115                 else
1116                         alloc_normal++;
1117                 nr_pages--;
1118                 nr_alloc++;
1119         }
1120
1121         return nr_alloc;
1122 }
1123
1124 static unsigned long preallocate_image_memory(unsigned long nr_pages)
1125 {
1126         return preallocate_image_pages(nr_pages, GFP_IMAGE);
1127 }
1128
1129 #ifdef CONFIG_HIGHMEM
1130 static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1131 {
1132         return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1133 }
1134
1135 /**
1136  *  __fraction - Compute (an approximation of) x * (multiplier / base)
1137  */
1138 static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1139 {
1140         x *= multiplier;
1141         do_div(x, base);
1142         return (unsigned long)x;
1143 }
1144
1145 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1146                                                 unsigned long highmem,
1147                                                 unsigned long total)
1148 {
1149         unsigned long alloc = __fraction(nr_pages, highmem, total);
1150
1151         return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1152 }
1153 #else /* CONFIG_HIGHMEM */
1154 static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1155 {
1156         return 0;
1157 }
1158
1159 static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1160                                                 unsigned long highmem,
1161                                                 unsigned long total)
1162 {
1163         return 0;
1164 }
1165 #endif /* CONFIG_HIGHMEM */
1166
1167 /**
1168  * free_unnecessary_pages - Release preallocated pages not needed for the image
1169  */
1170 static void free_unnecessary_pages(void)
1171 {
1172         unsigned long save_highmem, to_free_normal, to_free_highmem;
1173
1174         to_free_normal = alloc_normal - count_data_pages();
1175         save_highmem = count_highmem_pages();
1176         if (alloc_highmem > save_highmem) {
1177                 to_free_highmem = alloc_highmem - save_highmem;
1178         } else {
1179                 to_free_highmem = 0;
1180                 to_free_normal -= save_highmem - alloc_highmem;
1181         }
1182
1183         memory_bm_position_reset(&copy_bm);
1184
1185         while (to_free_normal > 0 || to_free_highmem > 0) {
1186                 unsigned long pfn = memory_bm_next_pfn(&copy_bm);
1187                 struct page *page = pfn_to_page(pfn);
1188
1189                 if (PageHighMem(page)) {
1190                         if (!to_free_highmem)
1191                                 continue;
1192                         to_free_highmem--;
1193                         alloc_highmem--;
1194                 } else {
1195                         if (!to_free_normal)
1196                                 continue;
1197                         to_free_normal--;
1198                         alloc_normal--;
1199                 }
1200                 memory_bm_clear_bit(&copy_bm, pfn);
1201                 swsusp_unset_page_forbidden(page);
1202                 swsusp_unset_page_free(page);
1203                 __free_page(page);
1204         }
1205 }
1206
1207 /**
1208  * minimum_image_size - Estimate the minimum acceptable size of an image
1209  * @saveable: Number of saveable pages in the system.
1210  *
1211  * We want to avoid attempting to free too much memory too hard, so estimate the
1212  * minimum acceptable size of a hibernation image to use as the lower limit for
1213  * preallocating memory.
1214  *
1215  * We assume that the minimum image size should be proportional to
1216  *
1217  * [number of saveable pages] - [number of pages that can be freed in theory]
1218  *
1219  * where the second term is the sum of (1) reclaimable slab pages, (2) active
1220  * and (3) inactive anonymouns pages, (4) active and (5) inactive file pages,
1221  * minus mapped file pages.
1222  */
1223 static unsigned long minimum_image_size(unsigned long saveable)
1224 {
1225         unsigned long size;
1226
1227         size = global_page_state(NR_SLAB_RECLAIMABLE)
1228                 + global_page_state(NR_ACTIVE_ANON)
1229                 + global_page_state(NR_INACTIVE_ANON)
1230                 + global_page_state(NR_ACTIVE_FILE)
1231                 + global_page_state(NR_INACTIVE_FILE)
1232                 - global_page_state(NR_FILE_MAPPED);
1233
1234         return saveable <= size ? 0 : saveable - size;
1235 }
1236
1237 /**
1238  * hibernate_preallocate_memory - Preallocate memory for hibernation image
1239  *
1240  * To create a hibernation image it is necessary to make a copy of every page
1241  * frame in use.  We also need a number of page frames to be free during
1242  * hibernation for allocations made while saving the image and for device
1243  * drivers, in case they need to allocate memory from their hibernation
1244  * callbacks (these two numbers are given by PAGES_FOR_IO and SPARE_PAGES,
1245  * respectively, both of which are rough estimates).  To make this happen, we
1246  * compute the total number of available page frames and allocate at least
1247  *
1248  * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 + 2 * SPARE_PAGES
1249  *
1250  * of them, which corresponds to the maximum size of a hibernation image.
1251  *
1252  * If image_size is set below the number following from the above formula,
1253  * the preallocation of memory is continued until the total number of saveable
1254  * pages in the system is below the requested image size or the minimum
1255  * acceptable image size returned by minimum_image_size(), whichever is greater.
1256  */
1257 int hibernate_preallocate_memory(void)
1258 {
1259         struct zone *zone;
1260         unsigned long saveable, size, max_size, count, highmem, pages = 0;
1261         unsigned long alloc, save_highmem, pages_highmem;
1262         struct timeval start, stop;
1263         int error;
1264
1265         printk(KERN_INFO "PM: Preallocating image memory... ");
1266         do_gettimeofday(&start);
1267
1268         error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1269         if (error)
1270                 goto err_out;
1271
1272         error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
1273         if (error)
1274                 goto err_out;
1275
1276         alloc_normal = 0;
1277         alloc_highmem = 0;
1278
1279         /* Count the number of saveable data pages. */
1280         save_highmem = count_highmem_pages();
1281         saveable = count_data_pages();
1282
1283         /*
1284          * Compute the total number of page frames we can use (count) and the
1285          * number of pages needed for image metadata (size).
1286          */
1287         count = saveable;
1288         saveable += save_highmem;
1289         highmem = save_highmem;
1290         size = 0;
1291         for_each_populated_zone(zone) {
1292                 size += snapshot_additional_pages(zone);
1293                 if (is_highmem(zone))
1294                         highmem += zone_page_state(zone, NR_FREE_PAGES);
1295                 else
1296                         count += zone_page_state(zone, NR_FREE_PAGES);
1297         }
1298         count += highmem;
1299         count -= totalreserve_pages;
1300
1301         /* Compute the maximum number of saveable pages to leave in memory. */
1302         max_size = (count - (size + PAGES_FOR_IO)) / 2 - 2 * SPARE_PAGES;
1303         size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1304         if (size > max_size)
1305                 size = max_size;
1306         /*
1307          * If the maximum is not less than the current number of saveable pages
1308          * in memory, allocate page frames for the image and we're done.
1309          */
1310         if (size >= saveable) {
1311                 pages = preallocate_image_highmem(save_highmem);
1312                 pages += preallocate_image_memory(saveable - pages);
1313                 goto out;
1314         }
1315
1316         /* Estimate the minimum size of the image. */
1317         pages = minimum_image_size(saveable);
1318         if (size < pages)
1319                 size = min_t(unsigned long, pages, max_size);
1320
1321         /*
1322          * Let the memory management subsystem know that we're going to need a
1323          * large number of page frames to allocate and make it free some memory.
1324          * NOTE: If this is not done, performance will be hurt badly in some
1325          * test cases.
1326          */
1327         shrink_all_memory(saveable - size);
1328
1329         /*
1330          * The number of saveable pages in memory was too high, so apply some
1331          * pressure to decrease it.  First, make room for the largest possible
1332          * image and fail if that doesn't work.  Next, try to decrease the size
1333          * of the image as much as indicated by 'size' using allocations from
1334          * highmem and non-highmem zones separately.
1335          */
1336         pages_highmem = preallocate_image_highmem(highmem / 2);
1337         alloc = (count - max_size) - pages_highmem;
1338         pages = preallocate_image_memory(alloc);
1339         if (pages < alloc)
1340                 goto err_out;
1341         size = max_size - size;
1342         alloc = size;
1343         size = preallocate_highmem_fraction(size, highmem, count);
1344         pages_highmem += size;
1345         alloc -= size;
1346         pages += preallocate_image_memory(alloc);
1347         pages += pages_highmem;
1348
1349         /*
1350          * We only need as many page frames for the image as there are saveable
1351          * pages in memory, but we have allocated more.  Release the excessive
1352          * ones now.
1353          */
1354         free_unnecessary_pages();
1355
1356  out:
1357         do_gettimeofday(&stop);
1358         printk(KERN_CONT "done (allocated %lu pages)\n", pages);
1359         swsusp_show_speed(&start, &stop, pages, "Allocated");
1360
1361         return 0;
1362
1363  err_out:
1364         printk(KERN_CONT "\n");
1365         swsusp_free();
1366         return -ENOMEM;
1367 }
1368
1369 #ifdef CONFIG_HIGHMEM
1370 /**
1371   *     count_pages_for_highmem - compute the number of non-highmem pages
1372   *     that will be necessary for creating copies of highmem pages.
1373   */
1374
1375 static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1376 {
1377         unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
1378
1379         if (free_highmem >= nr_highmem)
1380                 nr_highmem = 0;
1381         else
1382                 nr_highmem -= free_highmem;
1383
1384         return nr_highmem;
1385 }
1386 #else
1387 static unsigned int
1388 count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1389 #endif /* CONFIG_HIGHMEM */
1390
1391 /**
1392  *      enough_free_mem - Make sure we have enough free memory for the
1393  *      snapshot image.
1394  */
1395
1396 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1397 {
1398         struct zone *zone;
1399         unsigned int free = alloc_normal;
1400
1401         for_each_populated_zone(zone)
1402                 if (!is_highmem(zone))
1403                         free += zone_page_state(zone, NR_FREE_PAGES);
1404
1405         nr_pages += count_pages_for_highmem(nr_highmem);
1406         pr_debug("PM: Normal pages needed: %u + %u, available pages: %u\n",
1407                 nr_pages, PAGES_FOR_IO, free);
1408
1409         return free > nr_pages + PAGES_FOR_IO;
1410 }
1411
1412 #ifdef CONFIG_HIGHMEM
1413 /**
1414  *      get_highmem_buffer - if there are some highmem pages in the suspend
1415  *      image, we may need the buffer to copy them and/or load their data.
1416  */
1417
1418 static inline int get_highmem_buffer(int safe_needed)
1419 {
1420         buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
1421         return buffer ? 0 : -ENOMEM;
1422 }
1423
1424 /**
1425  *      alloc_highmem_image_pages - allocate some highmem pages for the image.
1426  *      Try to allocate as many pages as needed, but if the number of free
1427  *      highmem pages is lesser than that, allocate them all.
1428  */
1429
1430 static inline unsigned int
1431 alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
1432 {
1433         unsigned int to_alloc = count_free_highmem_pages();
1434
1435         if (to_alloc > nr_highmem)
1436                 to_alloc = nr_highmem;
1437
1438         nr_highmem -= to_alloc;
1439         while (to_alloc-- > 0) {
1440                 struct page *page;
1441
1442                 page = alloc_image_page(__GFP_HIGHMEM);
1443                 memory_bm_set_bit(bm, page_to_pfn(page));
1444         }
1445         return nr_highmem;
1446 }
1447 #else
1448 static inline int get_highmem_buffer(int safe_needed) { return 0; }
1449
1450 static inline unsigned int
1451 alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
1452 #endif /* CONFIG_HIGHMEM */
1453
1454 /**
1455  *      swsusp_alloc - allocate memory for the suspend image
1456  *
1457  *      We first try to allocate as many highmem pages as there are
1458  *      saveable highmem pages in the system.  If that fails, we allocate
1459  *      non-highmem pages for the copies of the remaining highmem ones.
1460  *
1461  *      In this approach it is likely that the copies of highmem pages will
1462  *      also be located in the high memory, because of the way in which
1463  *      copy_data_pages() works.
1464  */
1465
1466 static int
1467 swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
1468                 unsigned int nr_pages, unsigned int nr_highmem)
1469 {
1470         int error = 0;
1471
1472         if (nr_highmem > 0) {
1473                 error = get_highmem_buffer(PG_ANY);
1474                 if (error)
1475                         goto err_out;
1476                 if (nr_highmem > alloc_highmem) {
1477                         nr_highmem -= alloc_highmem;
1478                         nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
1479                 }
1480         }
1481         if (nr_pages > alloc_normal) {
1482                 nr_pages -= alloc_normal;
1483                 while (nr_pages-- > 0) {
1484                         struct page *page;
1485
1486                         page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
1487                         if (!page)
1488                                 goto err_out;
1489                         memory_bm_set_bit(copy_bm, page_to_pfn(page));
1490                 }
1491         }
1492
1493         return 0;
1494
1495  err_out:
1496         swsusp_free();
1497         return error;
1498 }
1499
1500 asmlinkage int swsusp_save(void)
1501 {
1502         unsigned int nr_pages, nr_highmem;
1503
1504         printk(KERN_INFO "PM: Creating hibernation image:\n");
1505
1506         drain_local_pages(NULL);
1507         nr_pages = count_data_pages();
1508         nr_highmem = count_highmem_pages();
1509         printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);
1510
1511         if (!enough_free_mem(nr_pages, nr_highmem)) {
1512                 printk(KERN_ERR "PM: Not enough free memory\n");
1513                 return -ENOMEM;
1514         }
1515
1516         if (swsusp_alloc(&orig_bm, &copy_bm, nr_pages, nr_highmem)) {
1517                 printk(KERN_ERR "PM: Memory allocation failed\n");
1518                 return -ENOMEM;
1519         }
1520
1521         /* During allocating of suspend pagedir, new cold pages may appear.
1522          * Kill them.
1523          */
1524         drain_local_pages(NULL);
1525         copy_data_pages(&copy_bm, &orig_bm);
1526
1527         /*
1528          * End of critical section. From now on, we can write to memory,
1529          * but we should not touch disk. This specially means we must _not_
1530          * touch swap space! Except we must write out our image of course.
1531          */
1532
1533         nr_pages += nr_highmem;
1534         nr_copy_pages = nr_pages;
1535         nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
1536
1537         printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
1538                 nr_pages);
1539
1540         return 0;
1541 }
1542
1543 #ifndef CONFIG_ARCH_HIBERNATION_HEADER
1544 static int init_header_complete(struct swsusp_info *info)
1545 {
1546         memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
1547         info->version_code = LINUX_VERSION_CODE;
1548         return 0;
1549 }
1550
1551 static char *check_image_kernel(struct swsusp_info *info)
1552 {
1553         if (info->version_code != LINUX_VERSION_CODE)
1554                 return "kernel version";
1555         if (strcmp(info->uts.sysname,init_utsname()->sysname))
1556                 return "system type";
1557         if (strcmp(info->uts.release,init_utsname()->release))
1558                 return "kernel release";
1559         if (strcmp(info->uts.version,init_utsname()->version))
1560                 return "version";
1561         if (strcmp(info->uts.machine,init_utsname()->machine))
1562                 return "machine";
1563         return NULL;
1564 }
1565 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
1566
1567 unsigned long snapshot_get_image_size(void)
1568 {
1569         return nr_copy_pages + nr_meta_pages + 1;
1570 }
1571
1572 static int init_header(struct swsusp_info *info)
1573 {
1574         memset(info, 0, sizeof(struct swsusp_info));
1575         info->num_physpages = num_physpages;
1576         info->image_pages = nr_copy_pages;
1577         info->pages = snapshot_get_image_size();
1578         info->size = info->pages;
1579         info->size <<= PAGE_SHIFT;
1580         return init_header_complete(info);
1581 }
1582
1583 /**
1584  *      pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
1585  *      are stored in the array @buf[] (1 page at a time)
1586  */
1587
1588 static inline void
1589 pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
1590 {
1591         int j;
1592
1593         for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1594                 buf[j] = memory_bm_next_pfn(bm);
1595                 if (unlikely(buf[j] == BM_END_OF_MAP))
1596                         break;
1597         }
1598 }
1599
1600 /**
1601  *      snapshot_read_next - used for reading the system memory snapshot.
1602  *
1603  *      On the first call to it @handle should point to a zeroed
1604  *      snapshot_handle structure.  The structure gets updated and a pointer
1605  *      to it should be passed to this function every next time.
1606  *
1607  *      On success the function returns a positive number.  Then, the caller
1608  *      is allowed to read up to the returned number of bytes from the memory
1609  *      location computed by the data_of() macro.
1610  *
1611  *      The function returns 0 to indicate the end of data stream condition,
1612  *      and a negative number is returned on error.  In such cases the
1613  *      structure pointed to by @handle is not updated and should not be used
1614  *      any more.
1615  */
1616
1617 int snapshot_read_next(struct snapshot_handle *handle)
1618 {
1619         if (handle->cur > nr_meta_pages + nr_copy_pages)
1620                 return 0;
1621
1622         if (!buffer) {
1623                 /* This makes the buffer be freed by swsusp_free() */
1624                 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1625                 if (!buffer)
1626                         return -ENOMEM;
1627         }
1628         if (!handle->cur) {
1629                 int error;
1630
1631                 error = init_header((struct swsusp_info *)buffer);
1632                 if (error)
1633                         return error;
1634                 handle->buffer = buffer;
1635                 memory_bm_position_reset(&orig_bm);
1636                 memory_bm_position_reset(&copy_bm);
1637         } else if (handle->cur <= nr_meta_pages) {
1638                 memset(buffer, 0, PAGE_SIZE);
1639                 pack_pfns(buffer, &orig_bm);
1640         } else {
1641                 struct page *page;
1642
1643                 page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
1644                 if (PageHighMem(page)) {
1645                         /* Highmem pages are copied to the buffer,
1646                          * because we can't return with a kmapped
1647                          * highmem page (we may not be called again).
1648                          */
1649                         void *kaddr;
1650
1651                         kaddr = kmap_atomic(page, KM_USER0);
1652                         memcpy(buffer, kaddr, PAGE_SIZE);
1653                         kunmap_atomic(kaddr, KM_USER0);
1654                         handle->buffer = buffer;
1655                 } else {
1656                         handle->buffer = page_address(page);
1657                 }
1658         }
1659         handle->cur++;
1660         return PAGE_SIZE;
1661 }
1662
1663 /**
1664  *      mark_unsafe_pages - mark the pages that cannot be used for storing
1665  *      the image during resume, because they conflict with the pages that
1666  *      had been used before suspend
1667  */
1668
1669 static int mark_unsafe_pages(struct memory_bitmap *bm)
1670 {
1671         struct zone *zone;
1672         unsigned long pfn, max_zone_pfn;
1673
1674         /* Clear page flags */
1675         for_each_populated_zone(zone) {
1676                 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1677                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1678                         if (pfn_valid(pfn))
1679                                 swsusp_unset_page_free(pfn_to_page(pfn));
1680         }
1681
1682         /* Mark pages that correspond to the "original" pfns as "unsafe" */
1683         memory_bm_position_reset(bm);
1684         do {
1685                 pfn = memory_bm_next_pfn(bm);
1686                 if (likely(pfn != BM_END_OF_MAP)) {
1687                         if (likely(pfn_valid(pfn)))
1688                                 swsusp_set_page_free(pfn_to_page(pfn));
1689                         else
1690                                 return -EFAULT;
1691                 }
1692         } while (pfn != BM_END_OF_MAP);
1693
1694         allocated_unsafe_pages = 0;
1695
1696         return 0;
1697 }
1698
1699 static void
1700 duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
1701 {
1702         unsigned long pfn;
1703
1704         memory_bm_position_reset(src);
1705         pfn = memory_bm_next_pfn(src);
1706         while (pfn != BM_END_OF_MAP) {
1707                 memory_bm_set_bit(dst, pfn);
1708                 pfn = memory_bm_next_pfn(src);
1709         }
1710 }
1711
1712 static int check_header(struct swsusp_info *info)
1713 {
1714         char *reason;
1715
1716         reason = check_image_kernel(info);
1717         if (!reason && info->num_physpages != num_physpages)
1718                 reason = "memory size";
1719         if (reason) {
1720                 printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
1721                 return -EPERM;
1722         }
1723         return 0;
1724 }
1725
1726 /**
1727  *      load header - check the image header and copy data from it
1728  */
1729
1730 static int
1731 load_header(struct swsusp_info *info)
1732 {
1733         int error;
1734
1735         restore_pblist = NULL;
1736         error = check_header(info);
1737         if (!error) {
1738                 nr_copy_pages = info->image_pages;
1739                 nr_meta_pages = info->pages - info->image_pages - 1;
1740         }
1741         return error;
1742 }
1743
1744 /**
1745  *      unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
1746  *      the corresponding bit in the memory bitmap @bm
1747  */
1748 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
1749 {
1750         int j;
1751
1752         for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1753                 if (unlikely(buf[j] == BM_END_OF_MAP))
1754                         break;
1755
1756                 if (memory_bm_pfn_present(bm, buf[j]))
1757                         memory_bm_set_bit(bm, buf[j]);
1758                 else
1759                         return -EFAULT;
1760         }
1761
1762         return 0;
1763 }
1764
1765 /* List of "safe" pages that may be used to store data loaded from the suspend
1766  * image
1767  */
1768 static struct linked_page *safe_pages_list;
1769
1770 #ifdef CONFIG_HIGHMEM
1771 /* struct highmem_pbe is used for creating the list of highmem pages that
1772  * should be restored atomically during the resume from disk, because the page
1773  * frames they have occupied before the suspend are in use.
1774  */
1775 struct highmem_pbe {
1776         struct page *copy_page; /* data is here now */
1777         struct page *orig_page; /* data was here before the suspend */
1778         struct highmem_pbe *next;
1779 };
1780
1781 /* List of highmem PBEs needed for restoring the highmem pages that were
1782  * allocated before the suspend and included in the suspend image, but have
1783  * also been allocated by the "resume" kernel, so their contents cannot be
1784  * written directly to their "original" page frames.
1785  */
1786 static struct highmem_pbe *highmem_pblist;
1787
1788 /**
1789  *      count_highmem_image_pages - compute the number of highmem pages in the
1790  *      suspend image.  The bits in the memory bitmap @bm that correspond to the
1791  *      image pages are assumed to be set.
1792  */
1793
1794 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
1795 {
1796         unsigned long pfn;
1797         unsigned int cnt = 0;
1798
1799         memory_bm_position_reset(bm);
1800         pfn = memory_bm_next_pfn(bm);
1801         while (pfn != BM_END_OF_MAP) {
1802                 if (PageHighMem(pfn_to_page(pfn)))
1803                         cnt++;
1804
1805                 pfn = memory_bm_next_pfn(bm);
1806         }
1807         return cnt;
1808 }
1809
1810 /**
1811  *      prepare_highmem_image - try to allocate as many highmem pages as
1812  *      there are highmem image pages (@nr_highmem_p points to the variable
1813  *      containing the number of highmem image pages).  The pages that are
1814  *      "safe" (ie. will not be overwritten when the suspend image is
1815  *      restored) have the corresponding bits set in @bm (it must be
1816  *      unitialized).
1817  *
1818  *      NOTE: This function should not be called if there are no highmem
1819  *      image pages.
1820  */
1821
1822 static unsigned int safe_highmem_pages;
1823
1824 static struct memory_bitmap *safe_highmem_bm;
1825
1826 static int
1827 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1828 {
1829         unsigned int to_alloc;
1830
1831         if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
1832                 return -ENOMEM;
1833
1834         if (get_highmem_buffer(PG_SAFE))
1835                 return -ENOMEM;
1836
1837         to_alloc = count_free_highmem_pages();
1838         if (to_alloc > *nr_highmem_p)
1839                 to_alloc = *nr_highmem_p;
1840         else
1841                 *nr_highmem_p = to_alloc;
1842
1843         safe_highmem_pages = 0;
1844         while (to_alloc-- > 0) {
1845                 struct page *page;
1846
1847                 page = alloc_page(__GFP_HIGHMEM);
1848                 if (!swsusp_page_is_free(page)) {
1849                         /* The page is "safe", set its bit the bitmap */
1850                         memory_bm_set_bit(bm, page_to_pfn(page));
1851                         safe_highmem_pages++;
1852                 }
1853                 /* Mark the page as allocated */
1854                 swsusp_set_page_forbidden(page);
1855                 swsusp_set_page_free(page);
1856         }
1857         memory_bm_position_reset(bm);
1858         safe_highmem_bm = bm;
1859         return 0;
1860 }
1861
1862 /**
1863  *      get_highmem_page_buffer - for given highmem image page find the buffer
1864  *      that suspend_write_next() should set for its caller to write to.
1865  *
1866  *      If the page is to be saved to its "original" page frame or a copy of
1867  *      the page is to be made in the highmem, @buffer is returned.  Otherwise,
1868  *      the copy of the page is to be made in normal memory, so the address of
1869  *      the copy is returned.
1870  *
1871  *      If @buffer is returned, the caller of suspend_write_next() will write
1872  *      the page's contents to @buffer, so they will have to be copied to the
1873  *      right location on the next call to suspend_write_next() and it is done
1874  *      with the help of copy_last_highmem_page().  For this purpose, if
1875  *      @buffer is returned, @last_highmem page is set to the page to which
1876  *      the data will have to be copied from @buffer.
1877  */
1878
1879 static struct page *last_highmem_page;
1880
1881 static void *
1882 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1883 {
1884         struct highmem_pbe *pbe;
1885         void *kaddr;
1886
1887         if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
1888                 /* We have allocated the "original" page frame and we can
1889                  * use it directly to store the loaded page.
1890                  */
1891                 last_highmem_page = page;
1892                 return buffer;
1893         }
1894         /* The "original" page frame has not been allocated and we have to
1895          * use a "safe" page frame to store the loaded page.
1896          */
1897         pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
1898         if (!pbe) {
1899                 swsusp_free();
1900                 return ERR_PTR(-ENOMEM);
1901         }
1902         pbe->orig_page = page;
1903         if (safe_highmem_pages > 0) {
1904                 struct page *tmp;
1905
1906                 /* Copy of the page will be stored in high memory */
1907                 kaddr = buffer;
1908                 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
1909                 safe_highmem_pages--;
1910                 last_highmem_page = tmp;
1911                 pbe->copy_page = tmp;
1912         } else {
1913                 /* Copy of the page will be stored in normal memory */
1914                 kaddr = safe_pages_list;
1915                 safe_pages_list = safe_pages_list->next;
1916                 pbe->copy_page = virt_to_page(kaddr);
1917         }
1918         pbe->next = highmem_pblist;
1919         highmem_pblist = pbe;
1920         return kaddr;
1921 }
1922
1923 /**
1924  *      copy_last_highmem_page - copy the contents of a highmem image from
1925  *      @buffer, where the caller of snapshot_write_next() has place them,
1926  *      to the right location represented by @last_highmem_page .
1927  */
1928
1929 static void copy_last_highmem_page(void)
1930 {
1931         if (last_highmem_page) {
1932                 void *dst;
1933
1934                 dst = kmap_atomic(last_highmem_page, KM_USER0);
1935                 memcpy(dst, buffer, PAGE_SIZE);
1936                 kunmap_atomic(dst, KM_USER0);
1937                 last_highmem_page = NULL;
1938         }
1939 }
1940
1941 static inline int last_highmem_page_copied(void)
1942 {
1943         return !last_highmem_page;
1944 }
1945
1946 static inline void free_highmem_data(void)
1947 {
1948         if (safe_highmem_bm)
1949                 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
1950
1951         if (buffer)
1952                 free_image_page(buffer, PG_UNSAFE_CLEAR);
1953 }
1954 #else
1955 static inline int get_safe_write_buffer(void) { return 0; }
1956
1957 static unsigned int
1958 count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
1959
1960 static inline int
1961 prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1962 {
1963         return 0;
1964 }
1965
1966 static inline void *
1967 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1968 {
1969         return ERR_PTR(-EINVAL);
1970 }
1971
1972 static inline void copy_last_highmem_page(void) {}
1973 static inline int last_highmem_page_copied(void) { return 1; }
1974 static inline void free_highmem_data(void) {}
1975 #endif /* CONFIG_HIGHMEM */
1976
1977 /**
1978  *      prepare_image - use the memory bitmap @bm to mark the pages that will
1979  *      be overwritten in the process of restoring the system memory state
1980  *      from the suspend image ("unsafe" pages) and allocate memory for the
1981  *      image.
1982  *
1983  *      The idea is to allocate a new memory bitmap first and then allocate
1984  *      as many pages as needed for the image data, but not to assign these
1985  *      pages to specific tasks initially.  Instead, we just mark them as
1986  *      allocated and create a lists of "safe" pages that will be used
1987  *      later.  On systems with high memory a list of "safe" highmem pages is
1988  *      also created.
1989  */
1990
1991 #define PBES_PER_LINKED_PAGE    (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
1992
1993 static int
1994 prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
1995 {
1996         unsigned int nr_pages, nr_highmem;
1997         struct linked_page *sp_list, *lp;
1998         int error;
1999
2000         /* If there is no highmem, the buffer will not be necessary */
2001         free_image_page(buffer, PG_UNSAFE_CLEAR);
2002         buffer = NULL;
2003
2004         nr_highmem = count_highmem_image_pages(bm);
2005         error = mark_unsafe_pages(bm);
2006         if (error)
2007                 goto Free;
2008
2009         error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
2010         if (error)
2011                 goto Free;
2012
2013         duplicate_memory_bitmap(new_bm, bm);
2014         memory_bm_free(bm, PG_UNSAFE_KEEP);
2015         if (nr_highmem > 0) {
2016                 error = prepare_highmem_image(bm, &nr_highmem);
2017                 if (error)
2018                         goto Free;
2019         }
2020         /* Reserve some safe pages for potential later use.
2021          *
2022          * NOTE: This way we make sure there will be enough safe pages for the
2023          * chain_alloc() in get_buffer().  It is a bit wasteful, but
2024          * nr_copy_pages cannot be greater than 50% of the memory anyway.
2025          */
2026         sp_list = NULL;
2027         /* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
2028         nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2029         nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2030         while (nr_pages > 0) {
2031                 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2032                 if (!lp) {
2033                         error = -ENOMEM;
2034                         goto Free;
2035                 }
2036                 lp->next = sp_list;
2037                 sp_list = lp;
2038                 nr_pages--;
2039         }
2040         /* Preallocate memory for the image */
2041         safe_pages_list = NULL;
2042         nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2043         while (nr_pages > 0) {
2044                 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2045                 if (!lp) {
2046                         error = -ENOMEM;
2047                         goto Free;
2048                 }
2049                 if (!swsusp_page_is_free(virt_to_page(lp))) {
2050                         /* The page is "safe", add it to the list */
2051                         lp->next = safe_pages_list;
2052                         safe_pages_list = lp;
2053                 }
2054                 /* Mark the page as allocated */
2055                 swsusp_set_page_forbidden(virt_to_page(lp));
2056                 swsusp_set_page_free(virt_to_page(lp));
2057                 nr_pages--;
2058         }
2059         /* Free the reserved safe pages so that chain_alloc() can use them */
2060         while (sp_list) {
2061                 lp = sp_list->next;
2062                 free_image_page(sp_list, PG_UNSAFE_CLEAR);
2063                 sp_list = lp;
2064         }
2065         return 0;
2066
2067  Free:
2068         swsusp_free();
2069         return error;
2070 }
2071
2072 /**
2073  *      get_buffer - compute the address that snapshot_write_next() should
2074  *      set for its caller to write to.
2075  */
2076
2077 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2078 {
2079         struct pbe *pbe;
2080         struct page *page;
2081         unsigned long pfn = memory_bm_next_pfn(bm);
2082
2083         if (pfn == BM_END_OF_MAP)
2084                 return ERR_PTR(-EFAULT);
2085
2086         page = pfn_to_page(pfn);
2087         if (PageHighMem(page))
2088                 return get_highmem_page_buffer(page, ca);
2089
2090         if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2091                 /* We have allocated the "original" page frame and we can
2092                  * use it directly to store the loaded page.
2093                  */
2094                 return page_address(page);
2095
2096         /* The "original" page frame has not been allocated and we have to
2097          * use a "safe" page frame to store the loaded page.
2098          */
2099         pbe = chain_alloc(ca, sizeof(struct pbe));
2100         if (!pbe) {
2101                 swsusp_free();
2102                 return ERR_PTR(-ENOMEM);
2103         }
2104         pbe->orig_address = page_address(page);
2105         pbe->address = safe_pages_list;
2106         safe_pages_list = safe_pages_list->next;
2107         pbe->next = restore_pblist;
2108         restore_pblist = pbe;
2109         return pbe->address;
2110 }
2111
2112 /**
2113  *      snapshot_write_next - used for writing the system memory snapshot.
2114  *
2115  *      On the first call to it @handle should point to a zeroed
2116  *      snapshot_handle structure.  The structure gets updated and a pointer
2117  *      to it should be passed to this function every next time.
2118  *
2119  *      On success the function returns a positive number.  Then, the caller
2120  *      is allowed to write up to the returned number of bytes to the memory
2121  *      location computed by the data_of() macro.
2122  *
2123  *      The function returns 0 to indicate the "end of file" condition,
2124  *      and a negative number is returned on error.  In such cases the
2125  *      structure pointed to by @handle is not updated and should not be used
2126  *      any more.
2127  */
2128
2129 int snapshot_write_next(struct snapshot_handle *handle)
2130 {
2131         static struct chain_allocator ca;
2132         int error = 0;
2133
2134         /* Check if we have already loaded the entire image */
2135         if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
2136                 return 0;
2137
2138         handle->sync_read = 1;
2139
2140         if (!handle->cur) {
2141                 if (!buffer)
2142                         /* This makes the buffer be freed by swsusp_free() */
2143                         buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2144
2145                 if (!buffer)
2146                         return -ENOMEM;
2147
2148                 handle->buffer = buffer;
2149         } else if (handle->cur == 1) {
2150                 error = load_header(buffer);
2151                 if (error)
2152                         return error;
2153
2154                 error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
2155                 if (error)
2156                         return error;
2157
2158         } else if (handle->cur <= nr_meta_pages + 1) {
2159                 error = unpack_orig_pfns(buffer, &copy_bm);
2160                 if (error)
2161                         return error;
2162
2163                 if (handle->cur == nr_meta_pages + 1) {
2164                         error = prepare_image(&orig_bm, &copy_bm);
2165                         if (error)
2166                                 return error;
2167
2168                         chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2169                         memory_bm_position_reset(&orig_bm);
2170                         restore_pblist = NULL;
2171                         handle->buffer = get_buffer(&orig_bm, &ca);
2172                         handle->sync_read = 0;
2173                         if (IS_ERR(handle->buffer))
2174                                 return PTR_ERR(handle->buffer);
2175                 }
2176         } else {
2177                 copy_last_highmem_page();
2178                 handle->buffer = get_buffer(&orig_bm, &ca);
2179                 if (IS_ERR(handle->buffer))
2180                         return PTR_ERR(handle->buffer);
2181                 if (handle->buffer != buffer)
2182                         handle->sync_read = 0;
2183         }
2184         handle->cur++;
2185         return PAGE_SIZE;
2186 }
2187
2188 /**
2189  *      snapshot_write_finalize - must be called after the last call to
2190  *      snapshot_write_next() in case the last page in the image happens
2191  *      to be a highmem page and its contents should be stored in the
2192  *      highmem.  Additionally, it releases the memory that will not be
2193  *      used any more.
2194  */
2195
2196 void snapshot_write_finalize(struct snapshot_handle *handle)
2197 {
2198         copy_last_highmem_page();
2199         /* Free only if we have loaded the image entirely */
2200         if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
2201                 memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
2202                 free_highmem_data();
2203         }
2204 }
2205
2206 int snapshot_image_loaded(struct snapshot_handle *handle)
2207 {
2208         return !(!nr_copy_pages || !last_highmem_page_copied() ||
2209                         handle->cur <= nr_meta_pages + nr_copy_pages);
2210 }
2211
2212 #ifdef CONFIG_HIGHMEM
2213 /* Assumes that @buf is ready and points to a "safe" page */
2214 static inline void
2215 swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
2216 {
2217         void *kaddr1, *kaddr2;
2218
2219         kaddr1 = kmap_atomic(p1, KM_USER0);
2220         kaddr2 = kmap_atomic(p2, KM_USER1);
2221         memcpy(buf, kaddr1, PAGE_SIZE);
2222         memcpy(kaddr1, kaddr2, PAGE_SIZE);
2223         memcpy(kaddr2, buf, PAGE_SIZE);
2224         kunmap_atomic(kaddr1, KM_USER0);
2225         kunmap_atomic(kaddr2, KM_USER1);
2226 }
2227
2228 /**
2229  *      restore_highmem - for each highmem page that was allocated before
2230  *      the suspend and included in the suspend image, and also has been
2231  *      allocated by the "resume" kernel swap its current (ie. "before
2232  *      resume") contents with the previous (ie. "before suspend") one.
2233  *
2234  *      If the resume eventually fails, we can call this function once
2235  *      again and restore the "before resume" highmem state.
2236  */
2237
2238 int restore_highmem(void)
2239 {
2240         struct highmem_pbe *pbe = highmem_pblist;
2241         void *buf;
2242
2243         if (!pbe)
2244                 return 0;
2245
2246         buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2247         if (!buf)
2248                 return -ENOMEM;
2249
2250         while (pbe) {
2251                 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2252                 pbe = pbe->next;
2253         }
2254         free_image_page(buf, PG_UNSAFE_CLEAR);
2255         return 0;
2256 }
2257 #endif /* CONFIG_HIGHMEM */