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TOMOYO Linux Cross Reference
Linux/kernel/power/swap.c

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  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 = rb_entry(*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)...\n",
452                 nr_to_write);
453         m = nr_to_write / 10;
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_INFO "PM: Image saving progress: %3d%%\n",
468                                nr_pages / m * 10);
469                 nr_pages++;
470         }
471         err2 = hib_wait_on_bio_chain(&bio);
472         do_gettimeofday(&stop);
473         if (!ret)
474                 ret = err2;
475         if (!ret)
476                 printk(KERN_INFO "PM: Image saving done.\n");
477         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
478         return ret;
479 }
480 
481 /**
482  * Structure used for CRC32.
483  */
484 struct crc_data {
485         struct task_struct *thr;                  /* thread */
486         atomic_t ready;                           /* ready to start flag */
487         atomic_t stop;                            /* ready to stop flag */
488         unsigned run_threads;                     /* nr current threads */
489         wait_queue_head_t go;                     /* start crc update */
490         wait_queue_head_t done;                   /* crc update done */
491         u32 *crc32;                               /* points to handle's crc32 */
492         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
493         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
494 };
495 
496 /**
497  * CRC32 update function that runs in its own thread.
498  */
499 static int crc32_threadfn(void *data)
500 {
501         struct crc_data *d = data;
502         unsigned i;
503 
504         while (1) {
505                 wait_event(d->go, atomic_read(&d->ready) ||
506                                   kthread_should_stop());
507                 if (kthread_should_stop()) {
508                         d->thr = NULL;
509                         atomic_set(&d->stop, 1);
510                         wake_up(&d->done);
511                         break;
512                 }
513                 atomic_set(&d->ready, 0);
514 
515                 for (i = 0; i < d->run_threads; i++)
516                         *d->crc32 = crc32_le(*d->crc32,
517                                              d->unc[i], *d->unc_len[i]);
518                 atomic_set(&d->stop, 1);
519                 wake_up(&d->done);
520         }
521         return 0;
522 }
523 /**
524  * Structure used for LZO data compression.
525  */
526 struct cmp_data {
527         struct task_struct *thr;                  /* thread */
528         atomic_t ready;                           /* ready to start flag */
529         atomic_t stop;                            /* ready to stop flag */
530         int ret;                                  /* return code */
531         wait_queue_head_t go;                     /* start compression */
532         wait_queue_head_t done;                   /* compression done */
533         size_t unc_len;                           /* uncompressed length */
534         size_t cmp_len;                           /* compressed length */
535         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
536         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
537         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
538 };
539 
540 /**
541  * Compression function that runs in its own thread.
542  */
543 static int lzo_compress_threadfn(void *data)
544 {
545         struct cmp_data *d = data;
546 
547         while (1) {
548                 wait_event(d->go, atomic_read(&d->ready) ||
549                                   kthread_should_stop());
550                 if (kthread_should_stop()) {
551                         d->thr = NULL;
552                         d->ret = -1;
553                         atomic_set(&d->stop, 1);
554                         wake_up(&d->done);
555                         break;
556                 }
557                 atomic_set(&d->ready, 0);
558 
559                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
560                                           d->cmp + LZO_HEADER, &d->cmp_len,
561                                           d->wrk);
562                 atomic_set(&d->stop, 1);
563                 wake_up(&d->done);
564         }
565         return 0;
566 }
567 
568 /**
569  * save_image_lzo - Save the suspend image data compressed with LZO.
570  * @handle: Swap mam handle to use for saving the image.
571  * @snapshot: Image to read data from.
572  * @nr_to_write: Number of pages to save.
573  */
574 static int save_image_lzo(struct swap_map_handle *handle,
575                           struct snapshot_handle *snapshot,
576                           unsigned int nr_to_write)
577 {
578         unsigned int m;
579         int ret = 0;
580         int nr_pages;
581         int err2;
582         struct bio *bio;
583         struct timeval start;
584         struct timeval stop;
585         size_t off;
586         unsigned thr, run_threads, nr_threads;
587         unsigned char *page = NULL;
588         struct cmp_data *data = NULL;
589         struct crc_data *crc = NULL;
590 
591         /*
592          * We'll limit the number of threads for compression to limit memory
593          * footprint.
594          */
595         nr_threads = num_online_cpus() - 1;
596         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
597 
598         page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
599         if (!page) {
600                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
601                 ret = -ENOMEM;
602                 goto out_clean;
603         }
604 
605         data = vmalloc(sizeof(*data) * nr_threads);
606         if (!data) {
607                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
608                 ret = -ENOMEM;
609                 goto out_clean;
610         }
611         for (thr = 0; thr < nr_threads; thr++)
612                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
613 
614         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
615         if (!crc) {
616                 printk(KERN_ERR "PM: Failed to allocate crc\n");
617                 ret = -ENOMEM;
618                 goto out_clean;
619         }
620         memset(crc, 0, offsetof(struct crc_data, go));
621 
622         /*
623          * Start the compression threads.
624          */
625         for (thr = 0; thr < nr_threads; thr++) {
626                 init_waitqueue_head(&data[thr].go);
627                 init_waitqueue_head(&data[thr].done);
628 
629                 data[thr].thr = kthread_run(lzo_compress_threadfn,
630                                             &data[thr],
631                                             "image_compress/%u", thr);
632                 if (IS_ERR(data[thr].thr)) {
633                         data[thr].thr = NULL;
634                         printk(KERN_ERR
635                                "PM: Cannot start compression threads\n");
636                         ret = -ENOMEM;
637                         goto out_clean;
638                 }
639         }
640 
641         /*
642          * Start the CRC32 thread.
643          */
644         init_waitqueue_head(&crc->go);
645         init_waitqueue_head(&crc->done);
646 
647         handle->crc32 = 0;
648         crc->crc32 = &handle->crc32;
649         for (thr = 0; thr < nr_threads; thr++) {
650                 crc->unc[thr] = data[thr].unc;
651                 crc->unc_len[thr] = &data[thr].unc_len;
652         }
653 
654         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
655         if (IS_ERR(crc->thr)) {
656                 crc->thr = NULL;
657                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
658                 ret = -ENOMEM;
659                 goto out_clean;
660         }
661 
662         /*
663          * Adjust the number of required free pages after all allocations have
664          * been done. We don't want to run out of pages when writing.
665          */
666         handle->reqd_free_pages = reqd_free_pages();
667 
668         printk(KERN_INFO
669                 "PM: Using %u thread(s) for compression.\n"
670                 "PM: Compressing and saving image data (%u pages)...\n",
671                 nr_threads, nr_to_write);
672         m = nr_to_write / 10;
673         if (!m)
674                 m = 1;
675         nr_pages = 0;
676         bio = NULL;
677         do_gettimeofday(&start);
678         for (;;) {
679                 for (thr = 0; thr < nr_threads; thr++) {
680                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
681                                 ret = snapshot_read_next(snapshot);
682                                 if (ret < 0)
683                                         goto out_finish;
684 
685                                 if (!ret)
686                                         break;
687 
688                                 memcpy(data[thr].unc + off,
689                                        data_of(*snapshot), PAGE_SIZE);
690 
691                                 if (!(nr_pages % m))
692                                         printk(KERN_INFO
693                                                "PM: Image saving progress: "
694                                                "%3d%%\n",
695                                                nr_pages / m * 10);
696                                 nr_pages++;
697                         }
698                         if (!off)
699                                 break;
700 
701                         data[thr].unc_len = off;
702 
703                         atomic_set(&data[thr].ready, 1);
704                         wake_up(&data[thr].go);
705                 }
706 
707                 if (!thr)
708                         break;
709 
710                 crc->run_threads = thr;
711                 atomic_set(&crc->ready, 1);
712                 wake_up(&crc->go);
713 
714                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
715                         wait_event(data[thr].done,
716                                    atomic_read(&data[thr].stop));
717                         atomic_set(&data[thr].stop, 0);
718 
719                         ret = data[thr].ret;
720 
721                         if (ret < 0) {
722                                 printk(KERN_ERR "PM: LZO compression failed\n");
723                                 goto out_finish;
724                         }
725 
726                         if (unlikely(!data[thr].cmp_len ||
727                                      data[thr].cmp_len >
728                                      lzo1x_worst_compress(data[thr].unc_len))) {
729                                 printk(KERN_ERR
730                                        "PM: Invalid LZO compressed length\n");
731                                 ret = -1;
732                                 goto out_finish;
733                         }
734 
735                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
736 
737                         /*
738                          * Given we are writing one page at a time to disk, we
739                          * copy that much from the buffer, although the last
740                          * bit will likely be smaller than full page. This is
741                          * OK - we saved the length of the compressed data, so
742                          * any garbage at the end will be discarded when we
743                          * read it.
744                          */
745                         for (off = 0;
746                              off < LZO_HEADER + data[thr].cmp_len;
747                              off += PAGE_SIZE) {
748                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
749 
750                                 ret = swap_write_page(handle, page, &bio);
751                                 if (ret)
752                                         goto out_finish;
753                         }
754                 }
755 
756                 wait_event(crc->done, atomic_read(&crc->stop));
757                 atomic_set(&crc->stop, 0);
758         }
759 
760 out_finish:
761         err2 = hib_wait_on_bio_chain(&bio);
762         do_gettimeofday(&stop);
763         if (!ret)
764                 ret = err2;
765         if (!ret)
766                 printk(KERN_INFO "PM: Image saving done.\n");
767         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
768 out_clean:
769         if (crc) {
770                 if (crc->thr)
771                         kthread_stop(crc->thr);
772                 kfree(crc);
773         }
774         if (data) {
775                 for (thr = 0; thr < nr_threads; thr++)
776                         if (data[thr].thr)
777                                 kthread_stop(data[thr].thr);
778                 vfree(data);
779         }
780         if (page) free_page((unsigned long)page);
781 
782         return ret;
783 }
784 
785 /**
786  *      enough_swap - Make sure we have enough swap to save the image.
787  *
788  *      Returns TRUE or FALSE after checking the total amount of swap
789  *      space avaiable from the resume partition.
790  */
791 
792 static int enough_swap(unsigned int nr_pages, unsigned int flags)
793 {
794         unsigned int free_swap = count_swap_pages(root_swap, 1);
795         unsigned int required;
796 
797         pr_debug("PM: Free swap pages: %u\n", free_swap);
798 
799         required = PAGES_FOR_IO + nr_pages;
800         return free_swap > required;
801 }
802 
803 /**
804  *      swsusp_write - Write entire image and metadata.
805  *      @flags: flags to pass to the "boot" kernel in the image header
806  *
807  *      It is important _NOT_ to umount filesystems at this point. We want
808  *      them synced (in case something goes wrong) but we DO not want to mark
809  *      filesystem clean: it is not. (And it does not matter, if we resume
810  *      correctly, we'll mark system clean, anyway.)
811  */
812 
813 int swsusp_write(unsigned int flags)
814 {
815         struct swap_map_handle handle;
816         struct snapshot_handle snapshot;
817         struct swsusp_info *header;
818         unsigned long pages;
819         int error;
820 
821         pages = snapshot_get_image_size();
822         error = get_swap_writer(&handle);
823         if (error) {
824                 printk(KERN_ERR "PM: Cannot get swap writer\n");
825                 return error;
826         }
827         if (flags & SF_NOCOMPRESS_MODE) {
828                 if (!enough_swap(pages, flags)) {
829                         printk(KERN_ERR "PM: Not enough free swap\n");
830                         error = -ENOSPC;
831                         goto out_finish;
832                 }
833         }
834         memset(&snapshot, 0, sizeof(struct snapshot_handle));
835         error = snapshot_read_next(&snapshot);
836         if (error < PAGE_SIZE) {
837                 if (error >= 0)
838                         error = -EFAULT;
839 
840                 goto out_finish;
841         }
842         header = (struct swsusp_info *)data_of(snapshot);
843         error = swap_write_page(&handle, header, NULL);
844         if (!error) {
845                 error = (flags & SF_NOCOMPRESS_MODE) ?
846                         save_image(&handle, &snapshot, pages - 1) :
847                         save_image_lzo(&handle, &snapshot, pages - 1);
848         }
849 out_finish:
850         error = swap_writer_finish(&handle, flags, error);
851         return error;
852 }
853 
854 /**
855  *      The following functions allow us to read data using a swap map
856  *      in a file-alike way
857  */
858 
859 static void release_swap_reader(struct swap_map_handle *handle)
860 {
861         struct swap_map_page_list *tmp;
862 
863         while (handle->maps) {
864                 if (handle->maps->map)
865                         free_page((unsigned long)handle->maps->map);
866                 tmp = handle->maps;
867                 handle->maps = handle->maps->next;
868                 kfree(tmp);
869         }
870         handle->cur = NULL;
871 }
872 
873 static int get_swap_reader(struct swap_map_handle *handle,
874                 unsigned int *flags_p)
875 {
876         int error;
877         struct swap_map_page_list *tmp, *last;
878         sector_t offset;
879 
880         *flags_p = swsusp_header->flags;
881 
882         if (!swsusp_header->image) /* how can this happen? */
883                 return -EINVAL;
884 
885         handle->cur = NULL;
886         last = handle->maps = NULL;
887         offset = swsusp_header->image;
888         while (offset) {
889                 tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
890                 if (!tmp) {
891                         release_swap_reader(handle);
892                         return -ENOMEM;
893                 }
894                 memset(tmp, 0, sizeof(*tmp));
895                 if (!handle->maps)
896                         handle->maps = tmp;
897                 if (last)
898                         last->next = tmp;
899                 last = tmp;
900 
901                 tmp->map = (struct swap_map_page *)
902                            __get_free_page(__GFP_WAIT | __GFP_HIGH);
903                 if (!tmp->map) {
904                         release_swap_reader(handle);
905                         return -ENOMEM;
906                 }
907 
908                 error = hib_bio_read_page(offset, tmp->map, NULL);
909                 if (error) {
910                         release_swap_reader(handle);
911                         return error;
912                 }
913                 offset = tmp->map->next_swap;
914         }
915         handle->k = 0;
916         handle->cur = handle->maps->map;
917         return 0;
918 }
919 
920 static int swap_read_page(struct swap_map_handle *handle, void *buf,
921                                 struct bio **bio_chain)
922 {
923         sector_t offset;
924         int error;
925         struct swap_map_page_list *tmp;
926 
927         if (!handle->cur)
928                 return -EINVAL;
929         offset = handle->cur->entries[handle->k];
930         if (!offset)
931                 return -EFAULT;
932         error = hib_bio_read_page(offset, buf, bio_chain);
933         if (error)
934                 return error;
935         if (++handle->k >= MAP_PAGE_ENTRIES) {
936                 handle->k = 0;
937                 free_page((unsigned long)handle->maps->map);
938                 tmp = handle->maps;
939                 handle->maps = handle->maps->next;
940                 kfree(tmp);
941                 if (!handle->maps)
942                         release_swap_reader(handle);
943                 else
944                         handle->cur = handle->maps->map;
945         }
946         return error;
947 }
948 
949 static int swap_reader_finish(struct swap_map_handle *handle)
950 {
951         release_swap_reader(handle);
952 
953         return 0;
954 }
955 
956 /**
957  *      load_image - load the image using the swap map handle
958  *      @handle and the snapshot handle @snapshot
959  *      (assume there are @nr_pages pages to load)
960  */
961 
962 static int load_image(struct swap_map_handle *handle,
963                       struct snapshot_handle *snapshot,
964                       unsigned int nr_to_read)
965 {
966         unsigned int m;
967         int ret = 0;
968         struct timeval start;
969         struct timeval stop;
970         struct bio *bio;
971         int err2;
972         unsigned nr_pages;
973 
974         printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
975                 nr_to_read);
976         m = nr_to_read / 10;
977         if (!m)
978                 m = 1;
979         nr_pages = 0;
980         bio = NULL;
981         do_gettimeofday(&start);
982         for ( ; ; ) {
983                 ret = snapshot_write_next(snapshot);
984                 if (ret <= 0)
985                         break;
986                 ret = swap_read_page(handle, data_of(*snapshot), &bio);
987                 if (ret)
988                         break;
989                 if (snapshot->sync_read)
990                         ret = hib_wait_on_bio_chain(&bio);
991                 if (ret)
992                         break;
993                 if (!(nr_pages % m))
994                         printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
995                                nr_pages / m * 10);
996                 nr_pages++;
997         }
998         err2 = hib_wait_on_bio_chain(&bio);
999         do_gettimeofday(&stop);
1000         if (!ret)
1001                 ret = err2;
1002         if (!ret) {
1003                 printk(KERN_INFO "PM: Image loading done.\n");
1004                 snapshot_write_finalize(snapshot);
1005                 if (!snapshot_image_loaded(snapshot))
1006                         ret = -ENODATA;
1007         }
1008         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
1009         return ret;
1010 }
1011 
1012 /**
1013  * Structure used for LZO data decompression.
1014  */
1015 struct dec_data {
1016         struct task_struct *thr;                  /* thread */
1017         atomic_t ready;                           /* ready to start flag */
1018         atomic_t stop;                            /* ready to stop flag */
1019         int ret;                                  /* return code */
1020         wait_queue_head_t go;                     /* start decompression */
1021         wait_queue_head_t done;                   /* decompression done */
1022         size_t unc_len;                           /* uncompressed length */
1023         size_t cmp_len;                           /* compressed length */
1024         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1025         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1026 };
1027 
1028 /**
1029  * Deompression function that runs in its own thread.
1030  */
1031 static int lzo_decompress_threadfn(void *data)
1032 {
1033         struct dec_data *d = data;
1034 
1035         while (1) {
1036                 wait_event(d->go, atomic_read(&d->ready) ||
1037                                   kthread_should_stop());
1038                 if (kthread_should_stop()) {
1039                         d->thr = NULL;
1040                         d->ret = -1;
1041                         atomic_set(&d->stop, 1);
1042                         wake_up(&d->done);
1043                         break;
1044                 }
1045                 atomic_set(&d->ready, 0);
1046 
1047                 d->unc_len = LZO_UNC_SIZE;
1048                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1049                                                d->unc, &d->unc_len);
1050                 atomic_set(&d->stop, 1);
1051                 wake_up(&d->done);
1052         }
1053         return 0;
1054 }
1055 
1056 /**
1057  * load_image_lzo - Load compressed image data and decompress them with LZO.
1058  * @handle: Swap map handle to use for loading data.
1059  * @snapshot: Image to copy uncompressed data into.
1060  * @nr_to_read: Number of pages to load.
1061  */
1062 static int load_image_lzo(struct swap_map_handle *handle,
1063                           struct snapshot_handle *snapshot,
1064                           unsigned int nr_to_read)
1065 {
1066         unsigned int m;
1067         int ret = 0;
1068         int eof = 0;
1069         struct bio *bio;
1070         struct timeval start;
1071         struct timeval stop;
1072         unsigned nr_pages;
1073         size_t off;
1074         unsigned i, thr, run_threads, nr_threads;
1075         unsigned ring = 0, pg = 0, ring_size = 0,
1076                  have = 0, want, need, asked = 0;
1077         unsigned long read_pages = 0;
1078         unsigned char **page = NULL;
1079         struct dec_data *data = NULL;
1080         struct crc_data *crc = NULL;
1081 
1082         /*
1083          * We'll limit the number of threads for decompression to limit memory
1084          * footprint.
1085          */
1086         nr_threads = num_online_cpus() - 1;
1087         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1088 
1089         page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1090         if (!page) {
1091                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1092                 ret = -ENOMEM;
1093                 goto out_clean;
1094         }
1095 
1096         data = vmalloc(sizeof(*data) * nr_threads);
1097         if (!data) {
1098                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1099                 ret = -ENOMEM;
1100                 goto out_clean;
1101         }
1102         for (thr = 0; thr < nr_threads; thr++)
1103                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1104 
1105         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1106         if (!crc) {
1107                 printk(KERN_ERR "PM: Failed to allocate crc\n");
1108                 ret = -ENOMEM;
1109                 goto out_clean;
1110         }
1111         memset(crc, 0, offsetof(struct crc_data, go));
1112 
1113         /*
1114          * Start the decompression threads.
1115          */
1116         for (thr = 0; thr < nr_threads; thr++) {
1117                 init_waitqueue_head(&data[thr].go);
1118                 init_waitqueue_head(&data[thr].done);
1119 
1120                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1121                                             &data[thr],
1122                                             "image_decompress/%u", thr);
1123                 if (IS_ERR(data[thr].thr)) {
1124                         data[thr].thr = NULL;
1125                         printk(KERN_ERR
1126                                "PM: Cannot start decompression threads\n");
1127                         ret = -ENOMEM;
1128                         goto out_clean;
1129                 }
1130         }
1131 
1132         /*
1133          * Start the CRC32 thread.
1134          */
1135         init_waitqueue_head(&crc->go);
1136         init_waitqueue_head(&crc->done);
1137 
1138         handle->crc32 = 0;
1139         crc->crc32 = &handle->crc32;
1140         for (thr = 0; thr < nr_threads; thr++) {
1141                 crc->unc[thr] = data[thr].unc;
1142                 crc->unc_len[thr] = &data[thr].unc_len;
1143         }
1144 
1145         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1146         if (IS_ERR(crc->thr)) {
1147                 crc->thr = NULL;
1148                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1149                 ret = -ENOMEM;
1150                 goto out_clean;
1151         }
1152 
1153         /*
1154          * Set the number of pages for read buffering.
1155          * This is complete guesswork, because we'll only know the real
1156          * picture once prepare_image() is called, which is much later on
1157          * during the image load phase. We'll assume the worst case and
1158          * say that none of the image pages are from high memory.
1159          */
1160         if (low_free_pages() > snapshot_get_image_size())
1161                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1162         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1163 
1164         for (i = 0; i < read_pages; i++) {
1165                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1166                                                   __GFP_WAIT | __GFP_HIGH :
1167                                                   __GFP_WAIT | __GFP_NOWARN |
1168                                                   __GFP_NORETRY);
1169 
1170                 if (!page[i]) {
1171                         if (i < LZO_CMP_PAGES) {
1172                                 ring_size = i;
1173                                 printk(KERN_ERR
1174                                        "PM: Failed to allocate LZO pages\n");
1175                                 ret = -ENOMEM;
1176                                 goto out_clean;
1177                         } else {
1178                                 break;
1179                         }
1180                 }
1181         }
1182         want = ring_size = i;
1183 
1184         printk(KERN_INFO
1185                 "PM: Using %u thread(s) for decompression.\n"
1186                 "PM: Loading and decompressing image data (%u pages)...\n",
1187                 nr_threads, nr_to_read);
1188         m = nr_to_read / 10;
1189         if (!m)
1190                 m = 1;
1191         nr_pages = 0;
1192         bio = NULL;
1193         do_gettimeofday(&start);
1194 
1195         ret = snapshot_write_next(snapshot);
1196         if (ret <= 0)
1197                 goto out_finish;
1198 
1199         for(;;) {
1200                 for (i = 0; !eof && i < want; i++) {
1201                         ret = swap_read_page(handle, page[ring], &bio);
1202                         if (ret) {
1203                                 /*
1204                                  * On real read error, finish. On end of data,
1205                                  * set EOF flag and just exit the read loop.
1206                                  */
1207                                 if (handle->cur &&
1208                                     handle->cur->entries[handle->k]) {
1209                                         goto out_finish;
1210                                 } else {
1211                                         eof = 1;
1212                                         break;
1213                                 }
1214                         }
1215                         if (++ring >= ring_size)
1216                                 ring = 0;
1217                 }
1218                 asked += i;
1219                 want -= i;
1220 
1221                 /*
1222                  * We are out of data, wait for some more.
1223                  */
1224                 if (!have) {
1225                         if (!asked)
1226                                 break;
1227 
1228                         ret = hib_wait_on_bio_chain(&bio);
1229                         if (ret)
1230                                 goto out_finish;
1231                         have += asked;
1232                         asked = 0;
1233                         if (eof)
1234                                 eof = 2;
1235                 }
1236 
1237                 if (crc->run_threads) {
1238                         wait_event(crc->done, atomic_read(&crc->stop));
1239                         atomic_set(&crc->stop, 0);
1240                         crc->run_threads = 0;
1241                 }
1242 
1243                 for (thr = 0; have && thr < nr_threads; thr++) {
1244                         data[thr].cmp_len = *(size_t *)page[pg];
1245                         if (unlikely(!data[thr].cmp_len ||
1246                                      data[thr].cmp_len >
1247                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1248                                 printk(KERN_ERR
1249                                        "PM: Invalid LZO compressed length\n");
1250                                 ret = -1;
1251                                 goto out_finish;
1252                         }
1253 
1254                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1255                                             PAGE_SIZE);
1256                         if (need > have) {
1257                                 if (eof > 1) {
1258                                         ret = -1;
1259                                         goto out_finish;
1260                                 }
1261                                 break;
1262                         }
1263 
1264                         for (off = 0;
1265                              off < LZO_HEADER + data[thr].cmp_len;
1266                              off += PAGE_SIZE) {
1267                                 memcpy(data[thr].cmp + off,
1268                                        page[pg], PAGE_SIZE);
1269                                 have--;
1270                                 want++;
1271                                 if (++pg >= ring_size)
1272                                         pg = 0;
1273                         }
1274 
1275                         atomic_set(&data[thr].ready, 1);
1276                         wake_up(&data[thr].go);
1277                 }
1278 
1279                 /*
1280                  * Wait for more data while we are decompressing.
1281                  */
1282                 if (have < LZO_CMP_PAGES && asked) {
1283                         ret = hib_wait_on_bio_chain(&bio);
1284                         if (ret)
1285                                 goto out_finish;
1286                         have += asked;
1287                         asked = 0;
1288                         if (eof)
1289                                 eof = 2;
1290                 }
1291 
1292                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1293                         wait_event(data[thr].done,
1294                                    atomic_read(&data[thr].stop));
1295                         atomic_set(&data[thr].stop, 0);
1296 
1297                         ret = data[thr].ret;
1298 
1299                         if (ret < 0) {
1300                                 printk(KERN_ERR
1301                                        "PM: LZO decompression failed\n");
1302                                 goto out_finish;
1303                         }
1304 
1305                         if (unlikely(!data[thr].unc_len ||
1306                                      data[thr].unc_len > LZO_UNC_SIZE ||
1307                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1308                                 printk(KERN_ERR
1309                                        "PM: Invalid LZO uncompressed length\n");
1310                                 ret = -1;
1311                                 goto out_finish;
1312                         }
1313 
1314                         for (off = 0;
1315                              off < data[thr].unc_len; off += PAGE_SIZE) {
1316                                 memcpy(data_of(*snapshot),
1317                                        data[thr].unc + off, PAGE_SIZE);
1318 
1319                                 if (!(nr_pages % m))
1320                                         printk(KERN_INFO
1321                                                "PM: Image loading progress: "
1322                                                "%3d%%\n",
1323                                                nr_pages / m * 10);
1324                                 nr_pages++;
1325 
1326                                 ret = snapshot_write_next(snapshot);
1327                                 if (ret <= 0) {
1328                                         crc->run_threads = thr + 1;
1329                                         atomic_set(&crc->ready, 1);
1330                                         wake_up(&crc->go);
1331                                         goto out_finish;
1332                                 }
1333                         }
1334                 }
1335 
1336                 crc->run_threads = thr;
1337                 atomic_set(&crc->ready, 1);
1338                 wake_up(&crc->go);
1339         }
1340 
1341 out_finish:
1342         if (crc->run_threads) {
1343                 wait_event(crc->done, atomic_read(&crc->stop));
1344                 atomic_set(&crc->stop, 0);
1345         }
1346         do_gettimeofday(&stop);
1347         if (!ret) {
1348                 printk(KERN_INFO "PM: Image loading done.\n");
1349                 snapshot_write_finalize(snapshot);
1350                 if (!snapshot_image_loaded(snapshot))
1351                         ret = -ENODATA;
1352                 if (!ret) {
1353                         if (swsusp_header->flags & SF_CRC32_MODE) {
1354                                 if(handle->crc32 != swsusp_header->crc32) {
1355                                         printk(KERN_ERR
1356                                                "PM: Invalid image CRC32!\n");
1357                                         ret = -ENODATA;
1358                                 }
1359                         }
1360                 }
1361         }
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 /**
1476  *      swsusp_unmark - Unmark swsusp signature in the resume device
1477  */
1478 
1479 #ifdef CONFIG_SUSPEND
1480 int swsusp_unmark(void)
1481 {
1482         int error;
1483 
1484         hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
1485         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1486                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1487                 error = hib_bio_write_page(swsusp_resume_block,
1488                                         swsusp_header, NULL);
1489         } else {
1490                 printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
1491                 error = -ENODEV;
1492         }
1493 
1494         /*
1495          * We just returned from suspend, we don't need the image any more.
1496          */
1497         free_all_swap_pages(root_swap);
1498 
1499         return error;
1500 }
1501 #endif
1502 
1503 static int swsusp_header_init(void)
1504 {
1505         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1506         if (!swsusp_header)
1507                 panic("Could not allocate memory for swsusp_header\n");
1508         return 0;
1509 }
1510 
1511 core_initcall(swsusp_header_init);
1512 

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