PM / Hibernate: Hibernate/thaw fixes/improvements
[linux-2.6.git] / kernel / power / swap.c
1 /*
2  * linux/kernel/power/swap.c
3  *
4  * This file provides functions for reading the suspend image from
5  * and writing it to a swap partition.
6  *
7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
9  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
10  *
11  * This file is released under the GPLv2.
12  *
13  */
14
15 #include <linux/module.h>
16 #include <linux/file.h>
17 #include <linux/delay.h>
18 #include <linux/bitops.h>
19 #include <linux/genhd.h>
20 #include <linux/device.h>
21 #include <linux/bio.h>
22 #include <linux/blkdev.h>
23 #include <linux/swap.h>
24 #include <linux/swapops.h>
25 #include <linux/pm.h>
26 #include <linux/slab.h>
27 #include <linux/lzo.h>
28 #include <linux/vmalloc.h>
29 #include <linux/cpumask.h>
30 #include <linux/atomic.h>
31 #include <linux/kthread.h>
32 #include <linux/crc32.h>
33
34 #include "power.h"
35
36 #define HIBERNATE_SIG   "S1SUSPEND"
37
38 /*
39  *      The swap map is a data structure used for keeping track of each page
40  *      written to a swap partition.  It consists of many swap_map_page
41  *      structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
42  *      These structures are stored on the swap and linked together with the
43  *      help of the .next_swap member.
44  *
45  *      The swap map is created during suspend.  The swap map pages are
46  *      allocated and populated one at a time, so we only need one memory
47  *      page to set up the entire structure.
48  *
49  *      During resume we pick up all swap_map_page structures into a list.
50  */
51
52 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
53
54 /*
55  * Number of free pages that are not high.
56  */
57 static inline unsigned long low_free_pages(void)
58 {
59         return nr_free_pages() - nr_free_highpages();
60 }
61
62 /*
63  * Number of pages required to be kept free while writing the image. Always
64  * half of all available low pages before the writing starts.
65  */
66 static inline unsigned long reqd_free_pages(void)
67 {
68         return low_free_pages() / 2;
69 }
70
71 struct swap_map_page {
72         sector_t entries[MAP_PAGE_ENTRIES];
73         sector_t next_swap;
74 };
75
76 struct swap_map_page_list {
77         struct swap_map_page *map;
78         struct swap_map_page_list *next;
79 };
80
81 /**
82  *      The swap_map_handle structure is used for handling swap in
83  *      a file-alike way
84  */
85
86 struct swap_map_handle {
87         struct swap_map_page *cur;
88         struct swap_map_page_list *maps;
89         sector_t cur_swap;
90         sector_t first_sector;
91         unsigned int k;
92         unsigned long reqd_free_pages;
93         u32 crc32;
94 };
95
96 struct swsusp_header {
97         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
98                       sizeof(u32)];
99         u32     crc32;
100         sector_t image;
101         unsigned int flags;     /* Flags to pass to the "boot" kernel */
102         char    orig_sig[10];
103         char    sig[10];
104 } __attribute__((packed));
105
106 static struct swsusp_header *swsusp_header;
107
108 /**
109  *      The following functions are used for tracing the allocated
110  *      swap pages, so that they can be freed in case of an error.
111  */
112
113 struct swsusp_extent {
114         struct rb_node node;
115         unsigned long start;
116         unsigned long end;
117 };
118
119 static struct rb_root swsusp_extents = RB_ROOT;
120
121 static int swsusp_extents_insert(unsigned long swap_offset)
122 {
123         struct rb_node **new = &(swsusp_extents.rb_node);
124         struct rb_node *parent = NULL;
125         struct swsusp_extent *ext;
126
127         /* Figure out where to put the new node */
128         while (*new) {
129                 ext = container_of(*new, struct swsusp_extent, node);
130                 parent = *new;
131                 if (swap_offset < ext->start) {
132                         /* Try to merge */
133                         if (swap_offset == ext->start - 1) {
134                                 ext->start--;
135                                 return 0;
136                         }
137                         new = &((*new)->rb_left);
138                 } else if (swap_offset > ext->end) {
139                         /* Try to merge */
140                         if (swap_offset == ext->end + 1) {
141                                 ext->end++;
142                                 return 0;
143                         }
144                         new = &((*new)->rb_right);
145                 } else {
146                         /* It already is in the tree */
147                         return -EINVAL;
148                 }
149         }
150         /* Add the new node and rebalance the tree. */
151         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
152         if (!ext)
153                 return -ENOMEM;
154
155         ext->start = swap_offset;
156         ext->end = swap_offset;
157         rb_link_node(&ext->node, parent, new);
158         rb_insert_color(&ext->node, &swsusp_extents);
159         return 0;
160 }
161
162 /**
163  *      alloc_swapdev_block - allocate a swap page and register that it has
164  *      been allocated, so that it can be freed in case of an error.
165  */
166
167 sector_t alloc_swapdev_block(int swap)
168 {
169         unsigned long offset;
170
171         offset = swp_offset(get_swap_page_of_type(swap));
172         if (offset) {
173                 if (swsusp_extents_insert(offset))
174                         swap_free(swp_entry(swap, offset));
175                 else
176                         return swapdev_block(swap, offset);
177         }
178         return 0;
179 }
180
181 /**
182  *      free_all_swap_pages - free swap pages allocated for saving image data.
183  *      It also frees the extents used to register which swap entries had been
184  *      allocated.
185  */
186
187 void free_all_swap_pages(int swap)
188 {
189         struct rb_node *node;
190
191         while ((node = swsusp_extents.rb_node)) {
192                 struct swsusp_extent *ext;
193                 unsigned long offset;
194
195                 ext = container_of(node, struct swsusp_extent, node);
196                 rb_erase(node, &swsusp_extents);
197                 for (offset = ext->start; offset <= ext->end; offset++)
198                         swap_free(swp_entry(swap, offset));
199
200                 kfree(ext);
201         }
202 }
203
204 int swsusp_swap_in_use(void)
205 {
206         return (swsusp_extents.rb_node != NULL);
207 }
208
209 /*
210  * General things
211  */
212
213 static unsigned short root_swap = 0xffff;
214 struct block_device *hib_resume_bdev;
215
216 /*
217  * Saving part
218  */
219
220 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
221 {
222         int error;
223
224         hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
225         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
226             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
227                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
228                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
229                 swsusp_header->image = handle->first_sector;
230                 swsusp_header->flags = flags;
231                 if (flags & SF_CRC32_MODE)
232                         swsusp_header->crc32 = handle->crc32;
233                 error = hib_bio_write_page(swsusp_resume_block,
234                                         swsusp_header, NULL);
235         } else {
236                 printk(KERN_ERR "PM: Swap header not found!\n");
237                 error = -ENODEV;
238         }
239         return error;
240 }
241
242 /**
243  *      swsusp_swap_check - check if the resume device is a swap device
244  *      and get its index (if so)
245  *
246  *      This is called before saving image
247  */
248 static int swsusp_swap_check(void)
249 {
250         int res;
251
252         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
253                         &hib_resume_bdev);
254         if (res < 0)
255                 return res;
256
257         root_swap = res;
258         res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
259         if (res)
260                 return res;
261
262         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
263         if (res < 0)
264                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
265
266         return res;
267 }
268
269 /**
270  *      write_page - Write one page to given swap location.
271  *      @buf:           Address we're writing.
272  *      @offset:        Offset of the swap page we're writing to.
273  *      @bio_chain:     Link the next write BIO here
274  */
275
276 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
277 {
278         void *src;
279         int ret;
280
281         if (!offset)
282                 return -ENOSPC;
283
284         if (bio_chain) {
285                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
286                                               __GFP_NORETRY);
287                 if (src) {
288                         copy_page(src, buf);
289                 } else {
290                         ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
291                         if (ret)
292                                 return ret;
293                         src = (void *)__get_free_page(__GFP_WAIT |
294                                                       __GFP_NOWARN |
295                                                       __GFP_NORETRY);
296                         if (src) {
297                                 copy_page(src, buf);
298                         } else {
299                                 WARN_ON_ONCE(1);
300                                 bio_chain = NULL;       /* Go synchronous */
301                                 src = buf;
302                         }
303                 }
304         } else {
305                 src = buf;
306         }
307         return hib_bio_write_page(offset, src, bio_chain);
308 }
309
310 static void release_swap_writer(struct swap_map_handle *handle)
311 {
312         if (handle->cur)
313                 free_page((unsigned long)handle->cur);
314         handle->cur = NULL;
315 }
316
317 static int get_swap_writer(struct swap_map_handle *handle)
318 {
319         int ret;
320
321         ret = swsusp_swap_check();
322         if (ret) {
323                 if (ret != -ENOSPC)
324                         printk(KERN_ERR "PM: Cannot find swap device, try "
325                                         "swapon -a.\n");
326                 return ret;
327         }
328         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
329         if (!handle->cur) {
330                 ret = -ENOMEM;
331                 goto err_close;
332         }
333         handle->cur_swap = alloc_swapdev_block(root_swap);
334         if (!handle->cur_swap) {
335                 ret = -ENOSPC;
336                 goto err_rel;
337         }
338         handle->k = 0;
339         handle->reqd_free_pages = reqd_free_pages();
340         handle->first_sector = handle->cur_swap;
341         return 0;
342 err_rel:
343         release_swap_writer(handle);
344 err_close:
345         swsusp_close(FMODE_WRITE);
346         return ret;
347 }
348
349 static int swap_write_page(struct swap_map_handle *handle, void *buf,
350                                 struct bio **bio_chain)
351 {
352         int error = 0;
353         sector_t offset;
354
355         if (!handle->cur)
356                 return -EINVAL;
357         offset = alloc_swapdev_block(root_swap);
358         error = write_page(buf, offset, bio_chain);
359         if (error)
360                 return error;
361         handle->cur->entries[handle->k++] = offset;
362         if (handle->k >= MAP_PAGE_ENTRIES) {
363                 offset = alloc_swapdev_block(root_swap);
364                 if (!offset)
365                         return -ENOSPC;
366                 handle->cur->next_swap = offset;
367                 error = write_page(handle->cur, handle->cur_swap, bio_chain);
368                 if (error)
369                         goto out;
370                 clear_page(handle->cur);
371                 handle->cur_swap = offset;
372                 handle->k = 0;
373
374                 if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
375                         error = hib_wait_on_bio_chain(bio_chain);
376                         if (error)
377                                 goto out;
378                         /*
379                          * Recalculate the number of required free pages, to
380                          * make sure we never take more than half.
381                          */
382                         handle->reqd_free_pages = reqd_free_pages();
383                 }
384         }
385  out:
386         return error;
387 }
388
389 static int flush_swap_writer(struct swap_map_handle *handle)
390 {
391         if (handle->cur && handle->cur_swap)
392                 return write_page(handle->cur, handle->cur_swap, NULL);
393         else
394                 return -EINVAL;
395 }
396
397 static int swap_writer_finish(struct swap_map_handle *handle,
398                 unsigned int flags, int error)
399 {
400         if (!error) {
401                 flush_swap_writer(handle);
402                 printk(KERN_INFO "PM: S");
403                 error = mark_swapfiles(handle, flags);
404                 printk("|\n");
405         }
406
407         if (error)
408                 free_all_swap_pages(root_swap);
409         release_swap_writer(handle);
410         swsusp_close(FMODE_WRITE);
411
412         return error;
413 }
414
415 /* We need to remember how much compressed data we need to read. */
416 #define LZO_HEADER      sizeof(size_t)
417
418 /* Number of pages/bytes we'll compress at one time. */
419 #define LZO_UNC_PAGES   32
420 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
421
422 /* Number of pages/bytes we need for compressed data (worst case). */
423 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
424                                      LZO_HEADER, PAGE_SIZE)
425 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
426
427 /* Maximum number of threads for compression/decompression. */
428 #define LZO_THREADS     3
429
430 /* Minimum/maximum number of pages for read buffering. */
431 #define LZO_MIN_RD_PAGES        1024
432 #define LZO_MAX_RD_PAGES        8192
433
434
435 /**
436  *      save_image - save the suspend image data
437  */
438
439 static int save_image(struct swap_map_handle *handle,
440                       struct snapshot_handle *snapshot,
441                       unsigned int nr_to_write)
442 {
443         unsigned int m;
444         int ret;
445         int nr_pages;
446         int err2;
447         struct bio *bio;
448         struct timeval start;
449         struct timeval stop;
450
451         printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
452                 nr_to_write);
453         m = nr_to_write / 100;
454         if (!m)
455                 m = 1;
456         nr_pages = 0;
457         bio = NULL;
458         do_gettimeofday(&start);
459         while (1) {
460                 ret = snapshot_read_next(snapshot);
461                 if (ret <= 0)
462                         break;
463                 ret = swap_write_page(handle, data_of(*snapshot), &bio);
464                 if (ret)
465                         break;
466                 if (!(nr_pages % m))
467                         printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
468                 nr_pages++;
469         }
470         err2 = hib_wait_on_bio_chain(&bio);
471         do_gettimeofday(&stop);
472         if (!ret)
473                 ret = err2;
474         if (!ret)
475                 printk(KERN_CONT "\b\b\b\bdone\n");
476         else
477                 printk(KERN_CONT "\n");
478         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
479         return ret;
480 }
481
482 /**
483  * Structure used for CRC32.
484  */
485 struct crc_data {
486         struct task_struct *thr;                  /* thread */
487         atomic_t ready;                           /* ready to start flag */
488         atomic_t stop;                            /* ready to stop flag */
489         unsigned run_threads;                     /* nr current threads */
490         wait_queue_head_t go;                     /* start crc update */
491         wait_queue_head_t done;                   /* crc update done */
492         u32 *crc32;                               /* points to handle's crc32 */
493         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
494         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
495 };
496
497 /**
498  * CRC32 update function that runs in its own thread.
499  */
500 static int crc32_threadfn(void *data)
501 {
502         struct crc_data *d = data;
503         unsigned i;
504
505         while (1) {
506                 wait_event(d->go, atomic_read(&d->ready) ||
507                                   kthread_should_stop());
508                 if (kthread_should_stop()) {
509                         d->thr = NULL;
510                         atomic_set(&d->stop, 1);
511                         wake_up(&d->done);
512                         break;
513                 }
514                 atomic_set(&d->ready, 0);
515
516                 for (i = 0; i < d->run_threads; i++)
517                         *d->crc32 = crc32_le(*d->crc32,
518                                              d->unc[i], *d->unc_len[i]);
519                 atomic_set(&d->stop, 1);
520                 wake_up(&d->done);
521         }
522         return 0;
523 }
524 /**
525  * Structure used for LZO data compression.
526  */
527 struct cmp_data {
528         struct task_struct *thr;                  /* thread */
529         atomic_t ready;                           /* ready to start flag */
530         atomic_t stop;                            /* ready to stop flag */
531         int ret;                                  /* return code */
532         wait_queue_head_t go;                     /* start compression */
533         wait_queue_head_t done;                   /* compression done */
534         size_t unc_len;                           /* uncompressed length */
535         size_t cmp_len;                           /* compressed length */
536         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
537         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
538         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
539 };
540
541 /**
542  * Compression function that runs in its own thread.
543  */
544 static int lzo_compress_threadfn(void *data)
545 {
546         struct cmp_data *d = data;
547
548         while (1) {
549                 wait_event(d->go, atomic_read(&d->ready) ||
550                                   kthread_should_stop());
551                 if (kthread_should_stop()) {
552                         d->thr = NULL;
553                         d->ret = -1;
554                         atomic_set(&d->stop, 1);
555                         wake_up(&d->done);
556                         break;
557                 }
558                 atomic_set(&d->ready, 0);
559
560                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
561                                           d->cmp + LZO_HEADER, &d->cmp_len,
562                                           d->wrk);
563                 atomic_set(&d->stop, 1);
564                 wake_up(&d->done);
565         }
566         return 0;
567 }
568
569 /**
570  * save_image_lzo - Save the suspend image data compressed with LZO.
571  * @handle: Swap mam handle to use for saving the image.
572  * @snapshot: Image to read data from.
573  * @nr_to_write: Number of pages to save.
574  */
575 static int save_image_lzo(struct swap_map_handle *handle,
576                           struct snapshot_handle *snapshot,
577                           unsigned int nr_to_write)
578 {
579         unsigned int m;
580         int ret = 0;
581         int nr_pages;
582         int err2;
583         struct bio *bio;
584         struct timeval start;
585         struct timeval stop;
586         size_t off;
587         unsigned thr, run_threads, nr_threads;
588         unsigned char *page = NULL;
589         struct cmp_data *data = NULL;
590         struct crc_data *crc = NULL;
591
592         /*
593          * We'll limit the number of threads for compression to limit memory
594          * footprint.
595          */
596         nr_threads = num_online_cpus() - 1;
597         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
598
599         page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
600         if (!page) {
601                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
602                 ret = -ENOMEM;
603                 goto out_clean;
604         }
605
606         data = vmalloc(sizeof(*data) * nr_threads);
607         if (!data) {
608                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
609                 ret = -ENOMEM;
610                 goto out_clean;
611         }
612         for (thr = 0; thr < nr_threads; thr++)
613                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
614
615         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
616         if (!crc) {
617                 printk(KERN_ERR "PM: Failed to allocate crc\n");
618                 ret = -ENOMEM;
619                 goto out_clean;
620         }
621         memset(crc, 0, offsetof(struct crc_data, go));
622
623         /*
624          * Start the compression threads.
625          */
626         for (thr = 0; thr < nr_threads; thr++) {
627                 init_waitqueue_head(&data[thr].go);
628                 init_waitqueue_head(&data[thr].done);
629
630                 data[thr].thr = kthread_run(lzo_compress_threadfn,
631                                             &data[thr],
632                                             "image_compress/%u", thr);
633                 if (IS_ERR(data[thr].thr)) {
634                         data[thr].thr = NULL;
635                         printk(KERN_ERR
636                                "PM: Cannot start compression threads\n");
637                         ret = -ENOMEM;
638                         goto out_clean;
639                 }
640         }
641
642         /*
643          * Start the CRC32 thread.
644          */
645         init_waitqueue_head(&crc->go);
646         init_waitqueue_head(&crc->done);
647
648         handle->crc32 = 0;
649         crc->crc32 = &handle->crc32;
650         for (thr = 0; thr < nr_threads; thr++) {
651                 crc->unc[thr] = data[thr].unc;
652                 crc->unc_len[thr] = &data[thr].unc_len;
653         }
654
655         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
656         if (IS_ERR(crc->thr)) {
657                 crc->thr = NULL;
658                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
659                 ret = -ENOMEM;
660                 goto out_clean;
661         }
662
663         /*
664          * Adjust the number of required free pages after all allocations have
665          * been done. We don't want to run out of pages when writing.
666          */
667         handle->reqd_free_pages = reqd_free_pages();
668
669         printk(KERN_INFO
670                 "PM: Using %u thread(s) for compression.\n"
671                 "PM: Compressing and saving image data (%u pages) ...     ",
672                 nr_threads, nr_to_write);
673         m = nr_to_write / 100;
674         if (!m)
675                 m = 1;
676         nr_pages = 0;
677         bio = NULL;
678         do_gettimeofday(&start);
679         for (;;) {
680                 for (thr = 0; thr < nr_threads; thr++) {
681                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
682                                 ret = snapshot_read_next(snapshot);
683                                 if (ret < 0)
684                                         goto out_finish;
685
686                                 if (!ret)
687                                         break;
688
689                                 memcpy(data[thr].unc + off,
690                                        data_of(*snapshot), PAGE_SIZE);
691
692                                 if (!(nr_pages % m))
693                                         printk(KERN_CONT "\b\b\b\b%3d%%",
694                                                nr_pages / m);
695                                 nr_pages++;
696                         }
697                         if (!off)
698                                 break;
699
700                         data[thr].unc_len = off;
701
702                         atomic_set(&data[thr].ready, 1);
703                         wake_up(&data[thr].go);
704                 }
705
706                 if (!thr)
707                         break;
708
709                 crc->run_threads = thr;
710                 atomic_set(&crc->ready, 1);
711                 wake_up(&crc->go);
712
713                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
714                         wait_event(data[thr].done,
715                                    atomic_read(&data[thr].stop));
716                         atomic_set(&data[thr].stop, 0);
717
718                         ret = data[thr].ret;
719
720                         if (ret < 0) {
721                                 printk(KERN_ERR "PM: LZO compression failed\n");
722                                 goto out_finish;
723                         }
724
725                         if (unlikely(!data[thr].cmp_len ||
726                                      data[thr].cmp_len >
727                                      lzo1x_worst_compress(data[thr].unc_len))) {
728                                 printk(KERN_ERR
729                                        "PM: Invalid LZO compressed length\n");
730                                 ret = -1;
731                                 goto out_finish;
732                         }
733
734                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
735
736                         /*
737                          * Given we are writing one page at a time to disk, we
738                          * copy that much from the buffer, although the last
739                          * bit will likely be smaller than full page. This is
740                          * OK - we saved the length of the compressed data, so
741                          * any garbage at the end will be discarded when we
742                          * read it.
743                          */
744                         for (off = 0;
745                              off < LZO_HEADER + data[thr].cmp_len;
746                              off += PAGE_SIZE) {
747                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
748
749                                 ret = swap_write_page(handle, page, &bio);
750                                 if (ret)
751                                         goto out_finish;
752                         }
753                 }
754
755                 wait_event(crc->done, atomic_read(&crc->stop));
756                 atomic_set(&crc->stop, 0);
757         }
758
759 out_finish:
760         err2 = hib_wait_on_bio_chain(&bio);
761         do_gettimeofday(&stop);
762         if (!ret)
763                 ret = err2;
764         if (!ret) {
765                 printk(KERN_CONT "\b\b\b\bdone\n");
766         } else {
767                 printk(KERN_CONT "\n");
768         }
769         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
770 out_clean:
771         if (crc) {
772                 if (crc->thr)
773                         kthread_stop(crc->thr);
774                 kfree(crc);
775         }
776         if (data) {
777                 for (thr = 0; thr < nr_threads; thr++)
778                         if (data[thr].thr)
779                                 kthread_stop(data[thr].thr);
780                 vfree(data);
781         }
782         if (page) free_page((unsigned long)page);
783
784         return ret;
785 }
786
787 /**
788  *      enough_swap - Make sure we have enough swap to save the image.
789  *
790  *      Returns TRUE or FALSE after checking the total amount of swap
791  *      space avaiable from the resume partition.
792  */
793
794 static int enough_swap(unsigned int nr_pages, unsigned int flags)
795 {
796         unsigned int free_swap = count_swap_pages(root_swap, 1);
797         unsigned int required;
798
799         pr_debug("PM: Free swap pages: %u\n", free_swap);
800
801         required = PAGES_FOR_IO + nr_pages;
802         return free_swap > required;
803 }
804
805 /**
806  *      swsusp_write - Write entire image and metadata.
807  *      @flags: flags to pass to the "boot" kernel in the image header
808  *
809  *      It is important _NOT_ to umount filesystems at this point. We want
810  *      them synced (in case something goes wrong) but we DO not want to mark
811  *      filesystem clean: it is not. (And it does not matter, if we resume
812  *      correctly, we'll mark system clean, anyway.)
813  */
814
815 int swsusp_write(unsigned int flags)
816 {
817         struct swap_map_handle handle;
818         struct snapshot_handle snapshot;
819         struct swsusp_info *header;
820         unsigned long pages;
821         int error;
822
823         pages = snapshot_get_image_size();
824         error = get_swap_writer(&handle);
825         if (error) {
826                 printk(KERN_ERR "PM: Cannot get swap writer\n");
827                 return error;
828         }
829         if (flags & SF_NOCOMPRESS_MODE) {
830                 if (!enough_swap(pages, flags)) {
831                         printk(KERN_ERR "PM: Not enough free swap\n");
832                         error = -ENOSPC;
833                         goto out_finish;
834                 }
835         }
836         memset(&snapshot, 0, sizeof(struct snapshot_handle));
837         error = snapshot_read_next(&snapshot);
838         if (error < PAGE_SIZE) {
839                 if (error >= 0)
840                         error = -EFAULT;
841
842                 goto out_finish;
843         }
844         header = (struct swsusp_info *)data_of(snapshot);
845         error = swap_write_page(&handle, header, NULL);
846         if (!error) {
847                 error = (flags & SF_NOCOMPRESS_MODE) ?
848                         save_image(&handle, &snapshot, pages - 1) :
849                         save_image_lzo(&handle, &snapshot, pages - 1);
850         }
851 out_finish:
852         error = swap_writer_finish(&handle, flags, error);
853         return error;
854 }
855
856 /**
857  *      The following functions allow us to read data using a swap map
858  *      in a file-alike way
859  */
860
861 static void release_swap_reader(struct swap_map_handle *handle)
862 {
863         struct swap_map_page_list *tmp;
864
865         while (handle->maps) {
866                 if (handle->maps->map)
867                         free_page((unsigned long)handle->maps->map);
868                 tmp = handle->maps;
869                 handle->maps = handle->maps->next;
870                 kfree(tmp);
871         }
872         handle->cur = NULL;
873 }
874
875 static int get_swap_reader(struct swap_map_handle *handle,
876                 unsigned int *flags_p)
877 {
878         int error;
879         struct swap_map_page_list *tmp, *last;
880         sector_t offset;
881
882         *flags_p = swsusp_header->flags;
883
884         if (!swsusp_header->image) /* how can this happen? */
885                 return -EINVAL;
886
887         handle->cur = NULL;
888         last = handle->maps = NULL;
889         offset = swsusp_header->image;
890         while (offset) {
891                 tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
892                 if (!tmp) {
893                         release_swap_reader(handle);
894                         return -ENOMEM;
895                 }
896                 memset(tmp, 0, sizeof(*tmp));
897                 if (!handle->maps)
898                         handle->maps = tmp;
899                 if (last)
900                         last->next = tmp;
901                 last = tmp;
902
903                 tmp->map = (struct swap_map_page *)
904                            __get_free_page(__GFP_WAIT | __GFP_HIGH);
905                 if (!tmp->map) {
906                         release_swap_reader(handle);
907                         return -ENOMEM;
908                 }
909
910                 error = hib_bio_read_page(offset, tmp->map, NULL);
911                 if (error) {
912                         release_swap_reader(handle);
913                         return error;
914                 }
915                 offset = tmp->map->next_swap;
916         }
917         handle->k = 0;
918         handle->cur = handle->maps->map;
919         return 0;
920 }
921
922 static int swap_read_page(struct swap_map_handle *handle, void *buf,
923                                 struct bio **bio_chain)
924 {
925         sector_t offset;
926         int error;
927         struct swap_map_page_list *tmp;
928
929         if (!handle->cur)
930                 return -EINVAL;
931         offset = handle->cur->entries[handle->k];
932         if (!offset)
933                 return -EFAULT;
934         error = hib_bio_read_page(offset, buf, bio_chain);
935         if (error)
936                 return error;
937         if (++handle->k >= MAP_PAGE_ENTRIES) {
938                 handle->k = 0;
939                 free_page((unsigned long)handle->maps->map);
940                 tmp = handle->maps;
941                 handle->maps = handle->maps->next;
942                 kfree(tmp);
943                 if (!handle->maps)
944                         release_swap_reader(handle);
945                 else
946                         handle->cur = handle->maps->map;
947         }
948         return error;
949 }
950
951 static int swap_reader_finish(struct swap_map_handle *handle)
952 {
953         release_swap_reader(handle);
954
955         return 0;
956 }
957
958 /**
959  *      load_image - load the image using the swap map handle
960  *      @handle and the snapshot handle @snapshot
961  *      (assume there are @nr_pages pages to load)
962  */
963
964 static int load_image(struct swap_map_handle *handle,
965                       struct snapshot_handle *snapshot,
966                       unsigned int nr_to_read)
967 {
968         unsigned int m;
969         int ret = 0;
970         struct timeval start;
971         struct timeval stop;
972         struct bio *bio;
973         int err2;
974         unsigned nr_pages;
975
976         printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
977                 nr_to_read);
978         m = nr_to_read / 100;
979         if (!m)
980                 m = 1;
981         nr_pages = 0;
982         bio = NULL;
983         do_gettimeofday(&start);
984         for ( ; ; ) {
985                 ret = snapshot_write_next(snapshot);
986                 if (ret <= 0)
987                         break;
988                 ret = swap_read_page(handle, data_of(*snapshot), &bio);
989                 if (ret)
990                         break;
991                 if (snapshot->sync_read)
992                         ret = hib_wait_on_bio_chain(&bio);
993                 if (ret)
994                         break;
995                 if (!(nr_pages % m))
996                         printk("\b\b\b\b%3d%%", nr_pages / m);
997                 nr_pages++;
998         }
999         err2 = hib_wait_on_bio_chain(&bio);
1000         do_gettimeofday(&stop);
1001         if (!ret)
1002                 ret = err2;
1003         if (!ret) {
1004                 printk("\b\b\b\bdone\n");
1005                 snapshot_write_finalize(snapshot);
1006                 if (!snapshot_image_loaded(snapshot))
1007                         ret = -ENODATA;
1008         } else
1009                 printk("\n");
1010         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
1011         return ret;
1012 }
1013
1014 /**
1015  * Structure used for LZO data decompression.
1016  */
1017 struct dec_data {
1018         struct task_struct *thr;                  /* thread */
1019         atomic_t ready;                           /* ready to start flag */
1020         atomic_t stop;                            /* ready to stop flag */
1021         int ret;                                  /* return code */
1022         wait_queue_head_t go;                     /* start decompression */
1023         wait_queue_head_t done;                   /* decompression done */
1024         size_t unc_len;                           /* uncompressed length */
1025         size_t cmp_len;                           /* compressed length */
1026         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1027         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1028 };
1029
1030 /**
1031  * Deompression function that runs in its own thread.
1032  */
1033 static int lzo_decompress_threadfn(void *data)
1034 {
1035         struct dec_data *d = data;
1036
1037         while (1) {
1038                 wait_event(d->go, atomic_read(&d->ready) ||
1039                                   kthread_should_stop());
1040                 if (kthread_should_stop()) {
1041                         d->thr = NULL;
1042                         d->ret = -1;
1043                         atomic_set(&d->stop, 1);
1044                         wake_up(&d->done);
1045                         break;
1046                 }
1047                 atomic_set(&d->ready, 0);
1048
1049                 d->unc_len = LZO_UNC_SIZE;
1050                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1051                                                d->unc, &d->unc_len);
1052                 atomic_set(&d->stop, 1);
1053                 wake_up(&d->done);
1054         }
1055         return 0;
1056 }
1057
1058 /**
1059  * load_image_lzo - Load compressed image data and decompress them with LZO.
1060  * @handle: Swap map handle to use for loading data.
1061  * @snapshot: Image to copy uncompressed data into.
1062  * @nr_to_read: Number of pages to load.
1063  */
1064 static int load_image_lzo(struct swap_map_handle *handle,
1065                           struct snapshot_handle *snapshot,
1066                           unsigned int nr_to_read)
1067 {
1068         unsigned int m;
1069         int ret = 0;
1070         int eof = 0;
1071         struct bio *bio;
1072         struct timeval start;
1073         struct timeval stop;
1074         unsigned nr_pages;
1075         size_t off;
1076         unsigned i, thr, run_threads, nr_threads;
1077         unsigned ring = 0, pg = 0, ring_size = 0,
1078                  have = 0, want, need, asked = 0;
1079         unsigned long read_pages = 0;
1080         unsigned char **page = NULL;
1081         struct dec_data *data = NULL;
1082         struct crc_data *crc = NULL;
1083
1084         /*
1085          * We'll limit the number of threads for decompression to limit memory
1086          * footprint.
1087          */
1088         nr_threads = num_online_cpus() - 1;
1089         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1090
1091         page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1092         if (!page) {
1093                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1094                 ret = -ENOMEM;
1095                 goto out_clean;
1096         }
1097
1098         data = vmalloc(sizeof(*data) * nr_threads);
1099         if (!data) {
1100                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1101                 ret = -ENOMEM;
1102                 goto out_clean;
1103         }
1104         for (thr = 0; thr < nr_threads; thr++)
1105                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1106
1107         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1108         if (!crc) {
1109                 printk(KERN_ERR "PM: Failed to allocate crc\n");
1110                 ret = -ENOMEM;
1111                 goto out_clean;
1112         }
1113         memset(crc, 0, offsetof(struct crc_data, go));
1114
1115         /*
1116          * Start the decompression threads.
1117          */
1118         for (thr = 0; thr < nr_threads; thr++) {
1119                 init_waitqueue_head(&data[thr].go);
1120                 init_waitqueue_head(&data[thr].done);
1121
1122                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1123                                             &data[thr],
1124                                             "image_decompress/%u", thr);
1125                 if (IS_ERR(data[thr].thr)) {
1126                         data[thr].thr = NULL;
1127                         printk(KERN_ERR
1128                                "PM: Cannot start decompression threads\n");
1129                         ret = -ENOMEM;
1130                         goto out_clean;
1131                 }
1132         }
1133
1134         /*
1135          * Start the CRC32 thread.
1136          */
1137         init_waitqueue_head(&crc->go);
1138         init_waitqueue_head(&crc->done);
1139
1140         handle->crc32 = 0;
1141         crc->crc32 = &handle->crc32;
1142         for (thr = 0; thr < nr_threads; thr++) {
1143                 crc->unc[thr] = data[thr].unc;
1144                 crc->unc_len[thr] = &data[thr].unc_len;
1145         }
1146
1147         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1148         if (IS_ERR(crc->thr)) {
1149                 crc->thr = NULL;
1150                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1151                 ret = -ENOMEM;
1152                 goto out_clean;
1153         }
1154
1155         /*
1156          * Set the number of pages for read buffering.
1157          * This is complete guesswork, because we'll only know the real
1158          * picture once prepare_image() is called, which is much later on
1159          * during the image load phase. We'll assume the worst case and
1160          * say that none of the image pages are from high memory.
1161          */
1162         if (low_free_pages() > snapshot_get_image_size())
1163                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1164         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1165
1166         for (i = 0; i < read_pages; i++) {
1167                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1168                                                   __GFP_WAIT | __GFP_HIGH :
1169                                                   __GFP_WAIT | __GFP_NOWARN |
1170                                                   __GFP_NORETRY);
1171
1172                 if (!page[i]) {
1173                         if (i < LZO_CMP_PAGES) {
1174                                 ring_size = i;
1175                                 printk(KERN_ERR
1176                                        "PM: Failed to allocate LZO pages\n");
1177                                 ret = -ENOMEM;
1178                                 goto out_clean;
1179                         } else {
1180                                 break;
1181                         }
1182                 }
1183         }
1184         want = ring_size = i;
1185
1186         printk(KERN_INFO
1187                 "PM: Using %u thread(s) for decompression.\n"
1188                 "PM: Loading and decompressing image data (%u pages) ...     ",
1189                 nr_threads, nr_to_read);
1190         m = nr_to_read / 100;
1191         if (!m)
1192                 m = 1;
1193         nr_pages = 0;
1194         bio = NULL;
1195         do_gettimeofday(&start);
1196
1197         ret = snapshot_write_next(snapshot);
1198         if (ret <= 0)
1199                 goto out_finish;
1200
1201         for(;;) {
1202                 for (i = 0; !eof && i < want; i++) {
1203                         ret = swap_read_page(handle, page[ring], &bio);
1204                         if (ret) {
1205                                 /*
1206                                  * On real read error, finish. On end of data,
1207                                  * set EOF flag and just exit the read loop.
1208                                  */
1209                                 if (handle->cur &&
1210                                     handle->cur->entries[handle->k]) {
1211                                         goto out_finish;
1212                                 } else {
1213                                         eof = 1;
1214                                         break;
1215                                 }
1216                         }
1217                         if (++ring >= ring_size)
1218                                 ring = 0;
1219                 }
1220                 asked += i;
1221                 want -= i;
1222
1223                 /*
1224                  * We are out of data, wait for some more.
1225                  */
1226                 if (!have) {
1227                         if (!asked)
1228                                 break;
1229
1230                         ret = hib_wait_on_bio_chain(&bio);
1231                         if (ret)
1232                                 goto out_finish;
1233                         have += asked;
1234                         asked = 0;
1235                         if (eof)
1236                                 eof = 2;
1237                 }
1238
1239                 if (crc->run_threads) {
1240                         wait_event(crc->done, atomic_read(&crc->stop));
1241                         atomic_set(&crc->stop, 0);
1242                         crc->run_threads = 0;
1243                 }
1244
1245                 for (thr = 0; have && thr < nr_threads; thr++) {
1246                         data[thr].cmp_len = *(size_t *)page[pg];
1247                         if (unlikely(!data[thr].cmp_len ||
1248                                      data[thr].cmp_len >
1249                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1250                                 printk(KERN_ERR
1251                                        "PM: Invalid LZO compressed length\n");
1252                                 ret = -1;
1253                                 goto out_finish;
1254                         }
1255
1256                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1257                                             PAGE_SIZE);
1258                         if (need > have) {
1259                                 if (eof > 1) {
1260                                         ret = -1;
1261                                         goto out_finish;
1262                                 }
1263                                 break;
1264                         }
1265
1266                         for (off = 0;
1267                              off < LZO_HEADER + data[thr].cmp_len;
1268                              off += PAGE_SIZE) {
1269                                 memcpy(data[thr].cmp + off,
1270                                        page[pg], PAGE_SIZE);
1271                                 have--;
1272                                 want++;
1273                                 if (++pg >= ring_size)
1274                                         pg = 0;
1275                         }
1276
1277                         atomic_set(&data[thr].ready, 1);
1278                         wake_up(&data[thr].go);
1279                 }
1280
1281                 /*
1282                  * Wait for more data while we are decompressing.
1283                  */
1284                 if (have < LZO_CMP_PAGES && asked) {
1285                         ret = hib_wait_on_bio_chain(&bio);
1286                         if (ret)
1287                                 goto out_finish;
1288                         have += asked;
1289                         asked = 0;
1290                         if (eof)
1291                                 eof = 2;
1292                 }
1293
1294                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1295                         wait_event(data[thr].done,
1296                                    atomic_read(&data[thr].stop));
1297                         atomic_set(&data[thr].stop, 0);
1298
1299                         ret = data[thr].ret;
1300
1301                         if (ret < 0) {
1302                                 printk(KERN_ERR
1303                                        "PM: LZO decompression failed\n");
1304                                 goto out_finish;
1305                         }
1306
1307                         if (unlikely(!data[thr].unc_len ||
1308                                      data[thr].unc_len > LZO_UNC_SIZE ||
1309                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1310                                 printk(KERN_ERR
1311                                        "PM: Invalid LZO uncompressed length\n");
1312                                 ret = -1;
1313                                 goto out_finish;
1314                         }
1315
1316                         for (off = 0;
1317                              off < data[thr].unc_len; off += PAGE_SIZE) {
1318                                 memcpy(data_of(*snapshot),
1319                                        data[thr].unc + off, PAGE_SIZE);
1320
1321                                 if (!(nr_pages % m))
1322                                         printk("\b\b\b\b%3d%%", nr_pages / m);
1323                                 nr_pages++;
1324
1325                                 ret = snapshot_write_next(snapshot);
1326                                 if (ret <= 0) {
1327                                         crc->run_threads = thr + 1;
1328                                         atomic_set(&crc->ready, 1);
1329                                         wake_up(&crc->go);
1330                                         goto out_finish;
1331                                 }
1332                         }
1333                 }
1334
1335                 crc->run_threads = thr;
1336                 atomic_set(&crc->ready, 1);
1337                 wake_up(&crc->go);
1338         }
1339
1340 out_finish:
1341         if (crc->run_threads) {
1342                 wait_event(crc->done, atomic_read(&crc->stop));
1343                 atomic_set(&crc->stop, 0);
1344         }
1345         do_gettimeofday(&stop);
1346         if (!ret) {
1347                 printk("\b\b\b\bdone\n");
1348                 snapshot_write_finalize(snapshot);
1349                 if (!snapshot_image_loaded(snapshot))
1350                         ret = -ENODATA;
1351                 if (!ret) {
1352                         if (swsusp_header->flags & SF_CRC32_MODE) {
1353                                 if(handle->crc32 != swsusp_header->crc32) {
1354                                         printk(KERN_ERR
1355                                                "PM: Invalid image CRC32!\n");
1356                                         ret = -ENODATA;
1357                                 }
1358                         }
1359                 }
1360         } else
1361                 printk("\n");
1362         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
1363 out_clean:
1364         for (i = 0; i < ring_size; i++)
1365                 free_page((unsigned long)page[i]);
1366         if (crc) {
1367                 if (crc->thr)
1368                         kthread_stop(crc->thr);
1369                 kfree(crc);
1370         }
1371         if (data) {
1372                 for (thr = 0; thr < nr_threads; thr++)
1373                         if (data[thr].thr)
1374                                 kthread_stop(data[thr].thr);
1375                 vfree(data);
1376         }
1377         if (page) vfree(page);
1378
1379         return ret;
1380 }
1381
1382 /**
1383  *      swsusp_read - read the hibernation image.
1384  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1385  *                be written into this memory location
1386  */
1387
1388 int swsusp_read(unsigned int *flags_p)
1389 {
1390         int error;
1391         struct swap_map_handle handle;
1392         struct snapshot_handle snapshot;
1393         struct swsusp_info *header;
1394
1395         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1396         error = snapshot_write_next(&snapshot);
1397         if (error < PAGE_SIZE)
1398                 return error < 0 ? error : -EFAULT;
1399         header = (struct swsusp_info *)data_of(snapshot);
1400         error = get_swap_reader(&handle, flags_p);
1401         if (error)
1402                 goto end;
1403         if (!error)
1404                 error = swap_read_page(&handle, header, NULL);
1405         if (!error) {
1406                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1407                         load_image(&handle, &snapshot, header->pages - 1) :
1408                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1409         }
1410         swap_reader_finish(&handle);
1411 end:
1412         if (!error)
1413                 pr_debug("PM: Image successfully loaded\n");
1414         else
1415                 pr_debug("PM: Error %d resuming\n", error);
1416         return error;
1417 }
1418
1419 /**
1420  *      swsusp_check - Check for swsusp signature in the resume device
1421  */
1422
1423 int swsusp_check(void)
1424 {
1425         int error;
1426
1427         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1428                                             FMODE_READ, NULL);
1429         if (!IS_ERR(hib_resume_bdev)) {
1430                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1431                 clear_page(swsusp_header);
1432                 error = hib_bio_read_page(swsusp_resume_block,
1433                                         swsusp_header, NULL);
1434                 if (error)
1435                         goto put;
1436
1437                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1438                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1439                         /* Reset swap signature now */
1440                         error = hib_bio_write_page(swsusp_resume_block,
1441                                                 swsusp_header, NULL);
1442                 } else {
1443                         error = -EINVAL;
1444                 }
1445
1446 put:
1447                 if (error)
1448                         blkdev_put(hib_resume_bdev, FMODE_READ);
1449                 else
1450                         pr_debug("PM: Image signature found, resuming\n");
1451         } else {
1452                 error = PTR_ERR(hib_resume_bdev);
1453         }
1454
1455         if (error)
1456                 pr_debug("PM: Image not found (code %d)\n", error);
1457
1458         return error;
1459 }
1460
1461 /**
1462  *      swsusp_close - close swap device.
1463  */
1464
1465 void swsusp_close(fmode_t mode)
1466 {
1467         if (IS_ERR(hib_resume_bdev)) {
1468                 pr_debug("PM: Image device not initialised\n");
1469                 return;
1470         }
1471
1472         blkdev_put(hib_resume_bdev, mode);
1473 }
1474
1475 static int swsusp_header_init(void)
1476 {
1477         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1478         if (!swsusp_header)
1479                 panic("Could not allocate memory for swsusp_header\n");
1480         return 0;
1481 }
1482
1483 core_initcall(swsusp_header_init);