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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 #include <linux/ktime.h>
 34 
 35 #include "power.h"
 36 
 37 #define HIBERNATE_SIG   "S1SUSPEND"
 38 
 39 /*
 40  * When reading an {un,}compressed image, we may restore pages in place,
 41  * in which case some architectures need these pages cleaning before they
 42  * can be executed. We don't know which pages these may be, so clean the lot.
 43  */
 44 static bool clean_pages_on_read;
 45 static bool clean_pages_on_decompress;
 46 
 47 /*
 48  *      The swap map is a data structure used for keeping track of each page
 49  *      written to a swap partition.  It consists of many swap_map_page
 50  *      structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
 51  *      These structures are stored on the swap and linked together with the
 52  *      help of the .next_swap member.
 53  *
 54  *      The swap map is created during suspend.  The swap map pages are
 55  *      allocated and populated one at a time, so we only need one memory
 56  *      page to set up the entire structure.
 57  *
 58  *      During resume we pick up all swap_map_page structures into a list.
 59  */
 60 
 61 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 62 
 63 /*
 64  * Number of free pages that are not high.
 65  */
 66 static inline unsigned long low_free_pages(void)
 67 {
 68         return nr_free_pages() - nr_free_highpages();
 69 }
 70 
 71 /*
 72  * Number of pages required to be kept free while writing the image. Always
 73  * half of all available low pages before the writing starts.
 74  */
 75 static inline unsigned long reqd_free_pages(void)
 76 {
 77         return low_free_pages() / 2;
 78 }
 79 
 80 struct swap_map_page {
 81         sector_t entries[MAP_PAGE_ENTRIES];
 82         sector_t next_swap;
 83 };
 84 
 85 struct swap_map_page_list {
 86         struct swap_map_page *map;
 87         struct swap_map_page_list *next;
 88 };
 89 
 90 /**
 91  *      The swap_map_handle structure is used for handling swap in
 92  *      a file-alike way
 93  */
 94 
 95 struct swap_map_handle {
 96         struct swap_map_page *cur;
 97         struct swap_map_page_list *maps;
 98         sector_t cur_swap;
 99         sector_t first_sector;
100         unsigned int k;
101         unsigned long reqd_free_pages;
102         u32 crc32;
103 };
104 
105 struct swsusp_header {
106         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
107                       sizeof(u32)];
108         u32     crc32;
109         sector_t image;
110         unsigned int flags;     /* Flags to pass to the "boot" kernel */
111         char    orig_sig[10];
112         char    sig[10];
113 } __packed;
114 
115 static struct swsusp_header *swsusp_header;
116 
117 /**
118  *      The following functions are used for tracing the allocated
119  *      swap pages, so that they can be freed in case of an error.
120  */
121 
122 struct swsusp_extent {
123         struct rb_node node;
124         unsigned long start;
125         unsigned long end;
126 };
127 
128 static struct rb_root swsusp_extents = RB_ROOT;
129 
130 static int swsusp_extents_insert(unsigned long swap_offset)
131 {
132         struct rb_node **new = &(swsusp_extents.rb_node);
133         struct rb_node *parent = NULL;
134         struct swsusp_extent *ext;
135 
136         /* Figure out where to put the new node */
137         while (*new) {
138                 ext = rb_entry(*new, struct swsusp_extent, node);
139                 parent = *new;
140                 if (swap_offset < ext->start) {
141                         /* Try to merge */
142                         if (swap_offset == ext->start - 1) {
143                                 ext->start--;
144                                 return 0;
145                         }
146                         new = &((*new)->rb_left);
147                 } else if (swap_offset > ext->end) {
148                         /* Try to merge */
149                         if (swap_offset == ext->end + 1) {
150                                 ext->end++;
151                                 return 0;
152                         }
153                         new = &((*new)->rb_right);
154                 } else {
155                         /* It already is in the tree */
156                         return -EINVAL;
157                 }
158         }
159         /* Add the new node and rebalance the tree. */
160         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
161         if (!ext)
162                 return -ENOMEM;
163 
164         ext->start = swap_offset;
165         ext->end = swap_offset;
166         rb_link_node(&ext->node, parent, new);
167         rb_insert_color(&ext->node, &swsusp_extents);
168         return 0;
169 }
170 
171 /**
172  *      alloc_swapdev_block - allocate a swap page and register that it has
173  *      been allocated, so that it can be freed in case of an error.
174  */
175 
176 sector_t alloc_swapdev_block(int swap)
177 {
178         unsigned long offset;
179 
180         offset = swp_offset(get_swap_page_of_type(swap));
181         if (offset) {
182                 if (swsusp_extents_insert(offset))
183                         swap_free(swp_entry(swap, offset));
184                 else
185                         return swapdev_block(swap, offset);
186         }
187         return 0;
188 }
189 
190 /**
191  *      free_all_swap_pages - free swap pages allocated for saving image data.
192  *      It also frees the extents used to register which swap entries had been
193  *      allocated.
194  */
195 
196 void free_all_swap_pages(int swap)
197 {
198         struct rb_node *node;
199 
200         while ((node = swsusp_extents.rb_node)) {
201                 struct swsusp_extent *ext;
202                 unsigned long offset;
203 
204                 ext = container_of(node, struct swsusp_extent, node);
205                 rb_erase(node, &swsusp_extents);
206                 for (offset = ext->start; offset <= ext->end; offset++)
207                         swap_free(swp_entry(swap, offset));
208 
209                 kfree(ext);
210         }
211 }
212 
213 int swsusp_swap_in_use(void)
214 {
215         return (swsusp_extents.rb_node != NULL);
216 }
217 
218 /*
219  * General things
220  */
221 
222 static unsigned short root_swap = 0xffff;
223 static struct block_device *hib_resume_bdev;
224 
225 struct hib_bio_batch {
226         atomic_t                count;
227         wait_queue_head_t       wait;
228         int                     error;
229 };
230 
231 static void hib_init_batch(struct hib_bio_batch *hb)
232 {
233         atomic_set(&hb->count, 0);
234         init_waitqueue_head(&hb->wait);
235         hb->error = 0;
236 }
237 
238 static void hib_end_io(struct bio *bio)
239 {
240         struct hib_bio_batch *hb = bio->bi_private;
241         struct page *page = bio->bi_io_vec[0].bv_page;
242 
243         if (bio->bi_error) {
244                 printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
245                                 imajor(bio->bi_bdev->bd_inode),
246                                 iminor(bio->bi_bdev->bd_inode),
247                                 (unsigned long long)bio->bi_iter.bi_sector);
248         }
249 
250         if (bio_data_dir(bio) == WRITE)
251                 put_page(page);
252         else if (clean_pages_on_read)
253                 flush_icache_range((unsigned long)page_address(page),
254                                    (unsigned long)page_address(page) + PAGE_SIZE);
255 
256         if (bio->bi_error && !hb->error)
257                 hb->error = bio->bi_error;
258         if (atomic_dec_and_test(&hb->count))
259                 wake_up(&hb->wait);
260 
261         bio_put(bio);
262 }
263 
264 static int hib_submit_io(int rw, pgoff_t page_off, void *addr,
265                 struct hib_bio_batch *hb)
266 {
267         struct page *page = virt_to_page(addr);
268         struct bio *bio;
269         int error = 0;
270 
271         bio = bio_alloc(__GFP_RECLAIM | __GFP_HIGH, 1);
272         bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
273         bio->bi_bdev = hib_resume_bdev;
274 
275         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
276                 printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
277                         (unsigned long long)bio->bi_iter.bi_sector);
278                 bio_put(bio);
279                 return -EFAULT;
280         }
281 
282         if (hb) {
283                 bio->bi_end_io = hib_end_io;
284                 bio->bi_private = hb;
285                 atomic_inc(&hb->count);
286                 submit_bio(rw, bio);
287         } else {
288                 error = submit_bio_wait(rw, bio);
289                 bio_put(bio);
290         }
291 
292         return error;
293 }
294 
295 static int hib_wait_io(struct hib_bio_batch *hb)
296 {
297         wait_event(hb->wait, atomic_read(&hb->count) == 0);
298         return hb->error;
299 }
300 
301 /*
302  * Saving part
303  */
304 
305 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
306 {
307         int error;
308 
309         hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
310         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
311             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
312                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
313                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
314                 swsusp_header->image = handle->first_sector;
315                 swsusp_header->flags = flags;
316                 if (flags & SF_CRC32_MODE)
317                         swsusp_header->crc32 = handle->crc32;
318                 error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
319                                         swsusp_header, NULL);
320         } else {
321                 printk(KERN_ERR "PM: Swap header not found!\n");
322                 error = -ENODEV;
323         }
324         return error;
325 }
326 
327 /**
328  *      swsusp_swap_check - check if the resume device is a swap device
329  *      and get its index (if so)
330  *
331  *      This is called before saving image
332  */
333 static int swsusp_swap_check(void)
334 {
335         int res;
336 
337         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
338                         &hib_resume_bdev);
339         if (res < 0)
340                 return res;
341 
342         root_swap = res;
343         res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
344         if (res)
345                 return res;
346 
347         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
348         if (res < 0)
349                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
350 
351         return res;
352 }
353 
354 /**
355  *      write_page - Write one page to given swap location.
356  *      @buf:           Address we're writing.
357  *      @offset:        Offset of the swap page we're writing to.
358  *      @hb:            bio completion batch
359  */
360 
361 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
362 {
363         void *src;
364         int ret;
365 
366         if (!offset)
367                 return -ENOSPC;
368 
369         if (hb) {
370                 src = (void *)__get_free_page(__GFP_RECLAIM | __GFP_NOWARN |
371                                               __GFP_NORETRY);
372                 if (src) {
373                         copy_page(src, buf);
374                 } else {
375                         ret = hib_wait_io(hb); /* Free pages */
376                         if (ret)
377                                 return ret;
378                         src = (void *)__get_free_page(__GFP_RECLAIM |
379                                                       __GFP_NOWARN |
380                                                       __GFP_NORETRY);
381                         if (src) {
382                                 copy_page(src, buf);
383                         } else {
384                                 WARN_ON_ONCE(1);
385                                 hb = NULL;      /* Go synchronous */
386                                 src = buf;
387                         }
388                 }
389         } else {
390                 src = buf;
391         }
392         return hib_submit_io(WRITE_SYNC, offset, src, hb);
393 }
394 
395 static void release_swap_writer(struct swap_map_handle *handle)
396 {
397         if (handle->cur)
398                 free_page((unsigned long)handle->cur);
399         handle->cur = NULL;
400 }
401 
402 static int get_swap_writer(struct swap_map_handle *handle)
403 {
404         int ret;
405 
406         ret = swsusp_swap_check();
407         if (ret) {
408                 if (ret != -ENOSPC)
409                         printk(KERN_ERR "PM: Cannot find swap device, try "
410                                         "swapon -a.\n");
411                 return ret;
412         }
413         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
414         if (!handle->cur) {
415                 ret = -ENOMEM;
416                 goto err_close;
417         }
418         handle->cur_swap = alloc_swapdev_block(root_swap);
419         if (!handle->cur_swap) {
420                 ret = -ENOSPC;
421                 goto err_rel;
422         }
423         handle->k = 0;
424         handle->reqd_free_pages = reqd_free_pages();
425         handle->first_sector = handle->cur_swap;
426         return 0;
427 err_rel:
428         release_swap_writer(handle);
429 err_close:
430         swsusp_close(FMODE_WRITE);
431         return ret;
432 }
433 
434 static int swap_write_page(struct swap_map_handle *handle, void *buf,
435                 struct hib_bio_batch *hb)
436 {
437         int error = 0;
438         sector_t offset;
439 
440         if (!handle->cur)
441                 return -EINVAL;
442         offset = alloc_swapdev_block(root_swap);
443         error = write_page(buf, offset, hb);
444         if (error)
445                 return error;
446         handle->cur->entries[handle->k++] = offset;
447         if (handle->k >= MAP_PAGE_ENTRIES) {
448                 offset = alloc_swapdev_block(root_swap);
449                 if (!offset)
450                         return -ENOSPC;
451                 handle->cur->next_swap = offset;
452                 error = write_page(handle->cur, handle->cur_swap, hb);
453                 if (error)
454                         goto out;
455                 clear_page(handle->cur);
456                 handle->cur_swap = offset;
457                 handle->k = 0;
458 
459                 if (hb && low_free_pages() <= handle->reqd_free_pages) {
460                         error = hib_wait_io(hb);
461                         if (error)
462                                 goto out;
463                         /*
464                          * Recalculate the number of required free pages, to
465                          * make sure we never take more than half.
466                          */
467                         handle->reqd_free_pages = reqd_free_pages();
468                 }
469         }
470  out:
471         return error;
472 }
473 
474 static int flush_swap_writer(struct swap_map_handle *handle)
475 {
476         if (handle->cur && handle->cur_swap)
477                 return write_page(handle->cur, handle->cur_swap, NULL);
478         else
479                 return -EINVAL;
480 }
481 
482 static int swap_writer_finish(struct swap_map_handle *handle,
483                 unsigned int flags, int error)
484 {
485         if (!error) {
486                 flush_swap_writer(handle);
487                 printk(KERN_INFO "PM: S");
488                 error = mark_swapfiles(handle, flags);
489                 printk("|\n");
490         }
491 
492         if (error)
493                 free_all_swap_pages(root_swap);
494         release_swap_writer(handle);
495         swsusp_close(FMODE_WRITE);
496 
497         return error;
498 }
499 
500 /* We need to remember how much compressed data we need to read. */
501 #define LZO_HEADER      sizeof(size_t)
502 
503 /* Number of pages/bytes we'll compress at one time. */
504 #define LZO_UNC_PAGES   32
505 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
506 
507 /* Number of pages/bytes we need for compressed data (worst case). */
508 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
509                                      LZO_HEADER, PAGE_SIZE)
510 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
511 
512 /* Maximum number of threads for compression/decompression. */
513 #define LZO_THREADS     3
514 
515 /* Minimum/maximum number of pages for read buffering. */
516 #define LZO_MIN_RD_PAGES        1024
517 #define LZO_MAX_RD_PAGES        8192
518 
519 
520 /**
521  *      save_image - save the suspend image data
522  */
523 
524 static int save_image(struct swap_map_handle *handle,
525                       struct snapshot_handle *snapshot,
526                       unsigned int nr_to_write)
527 {
528         unsigned int m;
529         int ret;
530         int nr_pages;
531         int err2;
532         struct hib_bio_batch hb;
533         ktime_t start;
534         ktime_t stop;
535 
536         hib_init_batch(&hb);
537 
538         printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
539                 nr_to_write);
540         m = nr_to_write / 10;
541         if (!m)
542                 m = 1;
543         nr_pages = 0;
544         start = ktime_get();
545         while (1) {
546                 ret = snapshot_read_next(snapshot);
547                 if (ret <= 0)
548                         break;
549                 ret = swap_write_page(handle, data_of(*snapshot), &hb);
550                 if (ret)
551                         break;
552                 if (!(nr_pages % m))
553                         printk(KERN_INFO "PM: Image saving progress: %3d%%\n",
554                                nr_pages / m * 10);
555                 nr_pages++;
556         }
557         err2 = hib_wait_io(&hb);
558         stop = ktime_get();
559         if (!ret)
560                 ret = err2;
561         if (!ret)
562                 printk(KERN_INFO "PM: Image saving done.\n");
563         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
564         return ret;
565 }
566 
567 /**
568  * Structure used for CRC32.
569  */
570 struct crc_data {
571         struct task_struct *thr;                  /* thread */
572         atomic_t ready;                           /* ready to start flag */
573         atomic_t stop;                            /* ready to stop flag */
574         unsigned run_threads;                     /* nr current threads */
575         wait_queue_head_t go;                     /* start crc update */
576         wait_queue_head_t done;                   /* crc update done */
577         u32 *crc32;                               /* points to handle's crc32 */
578         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
579         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
580 };
581 
582 /**
583  * CRC32 update function that runs in its own thread.
584  */
585 static int crc32_threadfn(void *data)
586 {
587         struct crc_data *d = data;
588         unsigned i;
589 
590         while (1) {
591                 wait_event(d->go, atomic_read(&d->ready) ||
592                                   kthread_should_stop());
593                 if (kthread_should_stop()) {
594                         d->thr = NULL;
595                         atomic_set(&d->stop, 1);
596                         wake_up(&d->done);
597                         break;
598                 }
599                 atomic_set(&d->ready, 0);
600 
601                 for (i = 0; i < d->run_threads; i++)
602                         *d->crc32 = crc32_le(*d->crc32,
603                                              d->unc[i], *d->unc_len[i]);
604                 atomic_set(&d->stop, 1);
605                 wake_up(&d->done);
606         }
607         return 0;
608 }
609 /**
610  * Structure used for LZO data compression.
611  */
612 struct cmp_data {
613         struct task_struct *thr;                  /* thread */
614         atomic_t ready;                           /* ready to start flag */
615         atomic_t stop;                            /* ready to stop flag */
616         int ret;                                  /* return code */
617         wait_queue_head_t go;                     /* start compression */
618         wait_queue_head_t done;                   /* compression done */
619         size_t unc_len;                           /* uncompressed length */
620         size_t cmp_len;                           /* compressed length */
621         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
622         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
623         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
624 };
625 
626 /**
627  * Compression function that runs in its own thread.
628  */
629 static int lzo_compress_threadfn(void *data)
630 {
631         struct cmp_data *d = data;
632 
633         while (1) {
634                 wait_event(d->go, atomic_read(&d->ready) ||
635                                   kthread_should_stop());
636                 if (kthread_should_stop()) {
637                         d->thr = NULL;
638                         d->ret = -1;
639                         atomic_set(&d->stop, 1);
640                         wake_up(&d->done);
641                         break;
642                 }
643                 atomic_set(&d->ready, 0);
644 
645                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
646                                           d->cmp + LZO_HEADER, &d->cmp_len,
647                                           d->wrk);
648                 atomic_set(&d->stop, 1);
649                 wake_up(&d->done);
650         }
651         return 0;
652 }
653 
654 /**
655  * save_image_lzo - Save the suspend image data compressed with LZO.
656  * @handle: Swap map handle to use for saving the image.
657  * @snapshot: Image to read data from.
658  * @nr_to_write: Number of pages to save.
659  */
660 static int save_image_lzo(struct swap_map_handle *handle,
661                           struct snapshot_handle *snapshot,
662                           unsigned int nr_to_write)
663 {
664         unsigned int m;
665         int ret = 0;
666         int nr_pages;
667         int err2;
668         struct hib_bio_batch hb;
669         ktime_t start;
670         ktime_t stop;
671         size_t off;
672         unsigned thr, run_threads, nr_threads;
673         unsigned char *page = NULL;
674         struct cmp_data *data = NULL;
675         struct crc_data *crc = NULL;
676 
677         hib_init_batch(&hb);
678 
679         /*
680          * We'll limit the number of threads for compression to limit memory
681          * footprint.
682          */
683         nr_threads = num_online_cpus() - 1;
684         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
685 
686         page = (void *)__get_free_page(__GFP_RECLAIM | __GFP_HIGH);
687         if (!page) {
688                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
689                 ret = -ENOMEM;
690                 goto out_clean;
691         }
692 
693         data = vmalloc(sizeof(*data) * nr_threads);
694         if (!data) {
695                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
696                 ret = -ENOMEM;
697                 goto out_clean;
698         }
699         for (thr = 0; thr < nr_threads; thr++)
700                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
701 
702         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
703         if (!crc) {
704                 printk(KERN_ERR "PM: Failed to allocate crc\n");
705                 ret = -ENOMEM;
706                 goto out_clean;
707         }
708         memset(crc, 0, offsetof(struct crc_data, go));
709 
710         /*
711          * Start the compression threads.
712          */
713         for (thr = 0; thr < nr_threads; thr++) {
714                 init_waitqueue_head(&data[thr].go);
715                 init_waitqueue_head(&data[thr].done);
716 
717                 data[thr].thr = kthread_run(lzo_compress_threadfn,
718                                             &data[thr],
719                                             "image_compress/%u", thr);
720                 if (IS_ERR(data[thr].thr)) {
721                         data[thr].thr = NULL;
722                         printk(KERN_ERR
723                                "PM: Cannot start compression threads\n");
724                         ret = -ENOMEM;
725                         goto out_clean;
726                 }
727         }
728 
729         /*
730          * Start the CRC32 thread.
731          */
732         init_waitqueue_head(&crc->go);
733         init_waitqueue_head(&crc->done);
734 
735         handle->crc32 = 0;
736         crc->crc32 = &handle->crc32;
737         for (thr = 0; thr < nr_threads; thr++) {
738                 crc->unc[thr] = data[thr].unc;
739                 crc->unc_len[thr] = &data[thr].unc_len;
740         }
741 
742         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
743         if (IS_ERR(crc->thr)) {
744                 crc->thr = NULL;
745                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
746                 ret = -ENOMEM;
747                 goto out_clean;
748         }
749 
750         /*
751          * Adjust the number of required free pages after all allocations have
752          * been done. We don't want to run out of pages when writing.
753          */
754         handle->reqd_free_pages = reqd_free_pages();
755 
756         printk(KERN_INFO
757                 "PM: Using %u thread(s) for compression.\n"
758                 "PM: Compressing and saving image data (%u pages)...\n",
759                 nr_threads, nr_to_write);
760         m = nr_to_write / 10;
761         if (!m)
762                 m = 1;
763         nr_pages = 0;
764         start = ktime_get();
765         for (;;) {
766                 for (thr = 0; thr < nr_threads; thr++) {
767                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
768                                 ret = snapshot_read_next(snapshot);
769                                 if (ret < 0)
770                                         goto out_finish;
771 
772                                 if (!ret)
773                                         break;
774 
775                                 memcpy(data[thr].unc + off,
776                                        data_of(*snapshot), PAGE_SIZE);
777 
778                                 if (!(nr_pages % m))
779                                         printk(KERN_INFO
780                                                "PM: Image saving progress: "
781                                                "%3d%%\n",
782                                                nr_pages / m * 10);
783                                 nr_pages++;
784                         }
785                         if (!off)
786                                 break;
787 
788                         data[thr].unc_len = off;
789 
790                         atomic_set(&data[thr].ready, 1);
791                         wake_up(&data[thr].go);
792                 }
793 
794                 if (!thr)
795                         break;
796 
797                 crc->run_threads = thr;
798                 atomic_set(&crc->ready, 1);
799                 wake_up(&crc->go);
800 
801                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
802                         wait_event(data[thr].done,
803                                    atomic_read(&data[thr].stop));
804                         atomic_set(&data[thr].stop, 0);
805 
806                         ret = data[thr].ret;
807 
808                         if (ret < 0) {
809                                 printk(KERN_ERR "PM: LZO compression failed\n");
810                                 goto out_finish;
811                         }
812 
813                         if (unlikely(!data[thr].cmp_len ||
814                                      data[thr].cmp_len >
815                                      lzo1x_worst_compress(data[thr].unc_len))) {
816                                 printk(KERN_ERR
817                                        "PM: Invalid LZO compressed length\n");
818                                 ret = -1;
819                                 goto out_finish;
820                         }
821 
822                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
823 
824                         /*
825                          * Given we are writing one page at a time to disk, we
826                          * copy that much from the buffer, although the last
827                          * bit will likely be smaller than full page. This is
828                          * OK - we saved the length of the compressed data, so
829                          * any garbage at the end will be discarded when we
830                          * read it.
831                          */
832                         for (off = 0;
833                              off < LZO_HEADER + data[thr].cmp_len;
834                              off += PAGE_SIZE) {
835                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
836 
837                                 ret = swap_write_page(handle, page, &hb);
838                                 if (ret)
839                                         goto out_finish;
840                         }
841                 }
842 
843                 wait_event(crc->done, atomic_read(&crc->stop));
844                 atomic_set(&crc->stop, 0);
845         }
846 
847 out_finish:
848         err2 = hib_wait_io(&hb);
849         stop = ktime_get();
850         if (!ret)
851                 ret = err2;
852         if (!ret)
853                 printk(KERN_INFO "PM: Image saving done.\n");
854         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
855 out_clean:
856         if (crc) {
857                 if (crc->thr)
858                         kthread_stop(crc->thr);
859                 kfree(crc);
860         }
861         if (data) {
862                 for (thr = 0; thr < nr_threads; thr++)
863                         if (data[thr].thr)
864                                 kthread_stop(data[thr].thr);
865                 vfree(data);
866         }
867         if (page) free_page((unsigned long)page);
868 
869         return ret;
870 }
871 
872 /**
873  *      enough_swap - Make sure we have enough swap to save the image.
874  *
875  *      Returns TRUE or FALSE after checking the total amount of swap
876  *      space avaiable from the resume partition.
877  */
878 
879 static int enough_swap(unsigned int nr_pages, unsigned int flags)
880 {
881         unsigned int free_swap = count_swap_pages(root_swap, 1);
882         unsigned int required;
883 
884         pr_debug("PM: Free swap pages: %u\n", free_swap);
885 
886         required = PAGES_FOR_IO + nr_pages;
887         return free_swap > required;
888 }
889 
890 /**
891  *      swsusp_write - Write entire image and metadata.
892  *      @flags: flags to pass to the "boot" kernel in the image header
893  *
894  *      It is important _NOT_ to umount filesystems at this point. We want
895  *      them synced (in case something goes wrong) but we DO not want to mark
896  *      filesystem clean: it is not. (And it does not matter, if we resume
897  *      correctly, we'll mark system clean, anyway.)
898  */
899 
900 int swsusp_write(unsigned int flags)
901 {
902         struct swap_map_handle handle;
903         struct snapshot_handle snapshot;
904         struct swsusp_info *header;
905         unsigned long pages;
906         int error;
907 
908         pages = snapshot_get_image_size();
909         error = get_swap_writer(&handle);
910         if (error) {
911                 printk(KERN_ERR "PM: Cannot get swap writer\n");
912                 return error;
913         }
914         if (flags & SF_NOCOMPRESS_MODE) {
915                 if (!enough_swap(pages, flags)) {
916                         printk(KERN_ERR "PM: Not enough free swap\n");
917                         error = -ENOSPC;
918                         goto out_finish;
919                 }
920         }
921         memset(&snapshot, 0, sizeof(struct snapshot_handle));
922         error = snapshot_read_next(&snapshot);
923         if (error < PAGE_SIZE) {
924                 if (error >= 0)
925                         error = -EFAULT;
926 
927                 goto out_finish;
928         }
929         header = (struct swsusp_info *)data_of(snapshot);
930         error = swap_write_page(&handle, header, NULL);
931         if (!error) {
932                 error = (flags & SF_NOCOMPRESS_MODE) ?
933                         save_image(&handle, &snapshot, pages - 1) :
934                         save_image_lzo(&handle, &snapshot, pages - 1);
935         }
936 out_finish:
937         error = swap_writer_finish(&handle, flags, error);
938         return error;
939 }
940 
941 /**
942  *      The following functions allow us to read data using a swap map
943  *      in a file-alike way
944  */
945 
946 static void release_swap_reader(struct swap_map_handle *handle)
947 {
948         struct swap_map_page_list *tmp;
949 
950         while (handle->maps) {
951                 if (handle->maps->map)
952                         free_page((unsigned long)handle->maps->map);
953                 tmp = handle->maps;
954                 handle->maps = handle->maps->next;
955                 kfree(tmp);
956         }
957         handle->cur = NULL;
958 }
959 
960 static int get_swap_reader(struct swap_map_handle *handle,
961                 unsigned int *flags_p)
962 {
963         int error;
964         struct swap_map_page_list *tmp, *last;
965         sector_t offset;
966 
967         *flags_p = swsusp_header->flags;
968 
969         if (!swsusp_header->image) /* how can this happen? */
970                 return -EINVAL;
971 
972         handle->cur = NULL;
973         last = handle->maps = NULL;
974         offset = swsusp_header->image;
975         while (offset) {
976                 tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
977                 if (!tmp) {
978                         release_swap_reader(handle);
979                         return -ENOMEM;
980                 }
981                 memset(tmp, 0, sizeof(*tmp));
982                 if (!handle->maps)
983                         handle->maps = tmp;
984                 if (last)
985                         last->next = tmp;
986                 last = tmp;
987 
988                 tmp->map = (struct swap_map_page *)
989                            __get_free_page(__GFP_RECLAIM | __GFP_HIGH);
990                 if (!tmp->map) {
991                         release_swap_reader(handle);
992                         return -ENOMEM;
993                 }
994 
995                 error = hib_submit_io(READ_SYNC, offset, tmp->map, NULL);
996                 if (error) {
997                         release_swap_reader(handle);
998                         return error;
999                 }
1000                 offset = tmp->map->next_swap;
1001         }
1002         handle->k = 0;
1003         handle->cur = handle->maps->map;
1004         return 0;
1005 }
1006 
1007 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1008                 struct hib_bio_batch *hb)
1009 {
1010         sector_t offset;
1011         int error;
1012         struct swap_map_page_list *tmp;
1013 
1014         if (!handle->cur)
1015                 return -EINVAL;
1016         offset = handle->cur->entries[handle->k];
1017         if (!offset)
1018                 return -EFAULT;
1019         error = hib_submit_io(READ_SYNC, offset, buf, hb);
1020         if (error)
1021                 return error;
1022         if (++handle->k >= MAP_PAGE_ENTRIES) {
1023                 handle->k = 0;
1024                 free_page((unsigned long)handle->maps->map);
1025                 tmp = handle->maps;
1026                 handle->maps = handle->maps->next;
1027                 kfree(tmp);
1028                 if (!handle->maps)
1029                         release_swap_reader(handle);
1030                 else
1031                         handle->cur = handle->maps->map;
1032         }
1033         return error;
1034 }
1035 
1036 static int swap_reader_finish(struct swap_map_handle *handle)
1037 {
1038         release_swap_reader(handle);
1039 
1040         return 0;
1041 }
1042 
1043 /**
1044  *      load_image - load the image using the swap map handle
1045  *      @handle and the snapshot handle @snapshot
1046  *      (assume there are @nr_pages pages to load)
1047  */
1048 
1049 static int load_image(struct swap_map_handle *handle,
1050                       struct snapshot_handle *snapshot,
1051                       unsigned int nr_to_read)
1052 {
1053         unsigned int m;
1054         int ret = 0;
1055         ktime_t start;
1056         ktime_t stop;
1057         struct hib_bio_batch hb;
1058         int err2;
1059         unsigned nr_pages;
1060 
1061         hib_init_batch(&hb);
1062 
1063         clean_pages_on_read = true;
1064         printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
1065                 nr_to_read);
1066         m = nr_to_read / 10;
1067         if (!m)
1068                 m = 1;
1069         nr_pages = 0;
1070         start = ktime_get();
1071         for ( ; ; ) {
1072                 ret = snapshot_write_next(snapshot);
1073                 if (ret <= 0)
1074                         break;
1075                 ret = swap_read_page(handle, data_of(*snapshot), &hb);
1076                 if (ret)
1077                         break;
1078                 if (snapshot->sync_read)
1079                         ret = hib_wait_io(&hb);
1080                 if (ret)
1081                         break;
1082                 if (!(nr_pages % m))
1083                         printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
1084                                nr_pages / m * 10);
1085                 nr_pages++;
1086         }
1087         err2 = hib_wait_io(&hb);
1088         stop = ktime_get();
1089         if (!ret)
1090                 ret = err2;
1091         if (!ret) {
1092                 printk(KERN_INFO "PM: Image loading done.\n");
1093                 snapshot_write_finalize(snapshot);
1094                 if (!snapshot_image_loaded(snapshot))
1095                         ret = -ENODATA;
1096         }
1097         swsusp_show_speed(start, stop, nr_to_read, "Read");
1098         return ret;
1099 }
1100 
1101 /**
1102  * Structure used for LZO data decompression.
1103  */
1104 struct dec_data {
1105         struct task_struct *thr;                  /* thread */
1106         atomic_t ready;                           /* ready to start flag */
1107         atomic_t stop;                            /* ready to stop flag */
1108         int ret;                                  /* return code */
1109         wait_queue_head_t go;                     /* start decompression */
1110         wait_queue_head_t done;                   /* decompression done */
1111         size_t unc_len;                           /* uncompressed length */
1112         size_t cmp_len;                           /* compressed length */
1113         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1114         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1115 };
1116 
1117 /**
1118  * Deompression function that runs in its own thread.
1119  */
1120 static int lzo_decompress_threadfn(void *data)
1121 {
1122         struct dec_data *d = data;
1123 
1124         while (1) {
1125                 wait_event(d->go, atomic_read(&d->ready) ||
1126                                   kthread_should_stop());
1127                 if (kthread_should_stop()) {
1128                         d->thr = NULL;
1129                         d->ret = -1;
1130                         atomic_set(&d->stop, 1);
1131                         wake_up(&d->done);
1132                         break;
1133                 }
1134                 atomic_set(&d->ready, 0);
1135 
1136                 d->unc_len = LZO_UNC_SIZE;
1137                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1138                                                d->unc, &d->unc_len);
1139                 if (clean_pages_on_decompress)
1140                         flush_icache_range((unsigned long)d->unc,
1141                                            (unsigned long)d->unc + d->unc_len);
1142 
1143                 atomic_set(&d->stop, 1);
1144                 wake_up(&d->done);
1145         }
1146         return 0;
1147 }
1148 
1149 /**
1150  * load_image_lzo - Load compressed image data and decompress them with LZO.
1151  * @handle: Swap map handle to use for loading data.
1152  * @snapshot: Image to copy uncompressed data into.
1153  * @nr_to_read: Number of pages to load.
1154  */
1155 static int load_image_lzo(struct swap_map_handle *handle,
1156                           struct snapshot_handle *snapshot,
1157                           unsigned int nr_to_read)
1158 {
1159         unsigned int m;
1160         int ret = 0;
1161         int eof = 0;
1162         struct hib_bio_batch hb;
1163         ktime_t start;
1164         ktime_t stop;
1165         unsigned nr_pages;
1166         size_t off;
1167         unsigned i, thr, run_threads, nr_threads;
1168         unsigned ring = 0, pg = 0, ring_size = 0,
1169                  have = 0, want, need, asked = 0;
1170         unsigned long read_pages = 0;
1171         unsigned char **page = NULL;
1172         struct dec_data *data = NULL;
1173         struct crc_data *crc = NULL;
1174 
1175         hib_init_batch(&hb);
1176 
1177         /*
1178          * We'll limit the number of threads for decompression to limit memory
1179          * footprint.
1180          */
1181         nr_threads = num_online_cpus() - 1;
1182         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1183 
1184         page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1185         if (!page) {
1186                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1187                 ret = -ENOMEM;
1188                 goto out_clean;
1189         }
1190 
1191         data = vmalloc(sizeof(*data) * nr_threads);
1192         if (!data) {
1193                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1194                 ret = -ENOMEM;
1195                 goto out_clean;
1196         }
1197         for (thr = 0; thr < nr_threads; thr++)
1198                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1199 
1200         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1201         if (!crc) {
1202                 printk(KERN_ERR "PM: Failed to allocate crc\n");
1203                 ret = -ENOMEM;
1204                 goto out_clean;
1205         }
1206         memset(crc, 0, offsetof(struct crc_data, go));
1207 
1208         clean_pages_on_decompress = true;
1209 
1210         /*
1211          * Start the decompression threads.
1212          */
1213         for (thr = 0; thr < nr_threads; thr++) {
1214                 init_waitqueue_head(&data[thr].go);
1215                 init_waitqueue_head(&data[thr].done);
1216 
1217                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1218                                             &data[thr],
1219                                             "image_decompress/%u", thr);
1220                 if (IS_ERR(data[thr].thr)) {
1221                         data[thr].thr = NULL;
1222                         printk(KERN_ERR
1223                                "PM: Cannot start decompression threads\n");
1224                         ret = -ENOMEM;
1225                         goto out_clean;
1226                 }
1227         }
1228 
1229         /*
1230          * Start the CRC32 thread.
1231          */
1232         init_waitqueue_head(&crc->go);
1233         init_waitqueue_head(&crc->done);
1234 
1235         handle->crc32 = 0;
1236         crc->crc32 = &handle->crc32;
1237         for (thr = 0; thr < nr_threads; thr++) {
1238                 crc->unc[thr] = data[thr].unc;
1239                 crc->unc_len[thr] = &data[thr].unc_len;
1240         }
1241 
1242         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1243         if (IS_ERR(crc->thr)) {
1244                 crc->thr = NULL;
1245                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1246                 ret = -ENOMEM;
1247                 goto out_clean;
1248         }
1249 
1250         /*
1251          * Set the number of pages for read buffering.
1252          * This is complete guesswork, because we'll only know the real
1253          * picture once prepare_image() is called, which is much later on
1254          * during the image load phase. We'll assume the worst case and
1255          * say that none of the image pages are from high memory.
1256          */
1257         if (low_free_pages() > snapshot_get_image_size())
1258                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1259         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1260 
1261         for (i = 0; i < read_pages; i++) {
1262                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1263                                                   __GFP_RECLAIM | __GFP_HIGH :
1264                                                   __GFP_RECLAIM | __GFP_NOWARN |
1265                                                   __GFP_NORETRY);
1266 
1267                 if (!page[i]) {
1268                         if (i < LZO_CMP_PAGES) {
1269                                 ring_size = i;
1270                                 printk(KERN_ERR
1271                                        "PM: Failed to allocate LZO pages\n");
1272                                 ret = -ENOMEM;
1273                                 goto out_clean;
1274                         } else {
1275                                 break;
1276                         }
1277                 }
1278         }
1279         want = ring_size = i;
1280 
1281         printk(KERN_INFO
1282                 "PM: Using %u thread(s) for decompression.\n"
1283                 "PM: Loading and decompressing image data (%u pages)...\n",
1284                 nr_threads, nr_to_read);
1285         m = nr_to_read / 10;
1286         if (!m)
1287                 m = 1;
1288         nr_pages = 0;
1289         start = ktime_get();
1290 
1291         ret = snapshot_write_next(snapshot);
1292         if (ret <= 0)
1293                 goto out_finish;
1294 
1295         for(;;) {
1296                 for (i = 0; !eof && i < want; i++) {
1297                         ret = swap_read_page(handle, page[ring], &hb);
1298                         if (ret) {
1299                                 /*
1300                                  * On real read error, finish. On end of data,
1301                                  * set EOF flag and just exit the read loop.
1302                                  */
1303                                 if (handle->cur &&
1304                                     handle->cur->entries[handle->k]) {
1305                                         goto out_finish;
1306                                 } else {
1307                                         eof = 1;
1308                                         break;
1309                                 }
1310                         }
1311                         if (++ring >= ring_size)
1312                                 ring = 0;
1313                 }
1314                 asked += i;
1315                 want -= i;
1316 
1317                 /*
1318                  * We are out of data, wait for some more.
1319                  */
1320                 if (!have) {
1321                         if (!asked)
1322                                 break;
1323 
1324                         ret = hib_wait_io(&hb);
1325                         if (ret)
1326                                 goto out_finish;
1327                         have += asked;
1328                         asked = 0;
1329                         if (eof)
1330                                 eof = 2;
1331                 }
1332 
1333                 if (crc->run_threads) {
1334                         wait_event(crc->done, atomic_read(&crc->stop));
1335                         atomic_set(&crc->stop, 0);
1336                         crc->run_threads = 0;
1337                 }
1338 
1339                 for (thr = 0; have && thr < nr_threads; thr++) {
1340                         data[thr].cmp_len = *(size_t *)page[pg];
1341                         if (unlikely(!data[thr].cmp_len ||
1342                                      data[thr].cmp_len >
1343                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1344                                 printk(KERN_ERR
1345                                        "PM: Invalid LZO compressed length\n");
1346                                 ret = -1;
1347                                 goto out_finish;
1348                         }
1349 
1350                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1351                                             PAGE_SIZE);
1352                         if (need > have) {
1353                                 if (eof > 1) {
1354                                         ret = -1;
1355                                         goto out_finish;
1356                                 }
1357                                 break;
1358                         }
1359 
1360                         for (off = 0;
1361                              off < LZO_HEADER + data[thr].cmp_len;
1362                              off += PAGE_SIZE) {
1363                                 memcpy(data[thr].cmp + off,
1364                                        page[pg], PAGE_SIZE);
1365                                 have--;
1366                                 want++;
1367                                 if (++pg >= ring_size)
1368                                         pg = 0;
1369                         }
1370 
1371                         atomic_set(&data[thr].ready, 1);
1372                         wake_up(&data[thr].go);
1373                 }
1374 
1375                 /*
1376                  * Wait for more data while we are decompressing.
1377                  */
1378                 if (have < LZO_CMP_PAGES && asked) {
1379                         ret = hib_wait_io(&hb);
1380                         if (ret)
1381                                 goto out_finish;
1382                         have += asked;
1383                         asked = 0;
1384                         if (eof)
1385                                 eof = 2;
1386                 }
1387 
1388                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1389                         wait_event(data[thr].done,
1390                                    atomic_read(&data[thr].stop));
1391                         atomic_set(&data[thr].stop, 0);
1392 
1393                         ret = data[thr].ret;
1394 
1395                         if (ret < 0) {
1396                                 printk(KERN_ERR
1397                                        "PM: LZO decompression failed\n");
1398                                 goto out_finish;
1399                         }
1400 
1401                         if (unlikely(!data[thr].unc_len ||
1402                                      data[thr].unc_len > LZO_UNC_SIZE ||
1403                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1404                                 printk(KERN_ERR
1405                                        "PM: Invalid LZO uncompressed length\n");
1406                                 ret = -1;
1407                                 goto out_finish;
1408                         }
1409 
1410                         for (off = 0;
1411                              off < data[thr].unc_len; off += PAGE_SIZE) {
1412                                 memcpy(data_of(*snapshot),
1413                                        data[thr].unc + off, PAGE_SIZE);
1414 
1415                                 if (!(nr_pages % m))
1416                                         printk(KERN_INFO
1417                                                "PM: Image loading progress: "
1418                                                "%3d%%\n",
1419                                                nr_pages / m * 10);
1420                                 nr_pages++;
1421 
1422                                 ret = snapshot_write_next(snapshot);
1423                                 if (ret <= 0) {
1424                                         crc->run_threads = thr + 1;
1425                                         atomic_set(&crc->ready, 1);
1426                                         wake_up(&crc->go);
1427                                         goto out_finish;
1428                                 }
1429                         }
1430                 }
1431 
1432                 crc->run_threads = thr;
1433                 atomic_set(&crc->ready, 1);
1434                 wake_up(&crc->go);
1435         }
1436 
1437 out_finish:
1438         if (crc->run_threads) {
1439                 wait_event(crc->done, atomic_read(&crc->stop));
1440                 atomic_set(&crc->stop, 0);
1441         }
1442         stop = ktime_get();
1443         if (!ret) {
1444                 printk(KERN_INFO "PM: Image loading done.\n");
1445                 snapshot_write_finalize(snapshot);
1446                 if (!snapshot_image_loaded(snapshot))
1447                         ret = -ENODATA;
1448                 if (!ret) {
1449                         if (swsusp_header->flags & SF_CRC32_MODE) {
1450                                 if(handle->crc32 != swsusp_header->crc32) {
1451                                         printk(KERN_ERR
1452                                                "PM: Invalid image CRC32!\n");
1453                                         ret = -ENODATA;
1454                                 }
1455                         }
1456                 }
1457         }
1458         swsusp_show_speed(start, stop, nr_to_read, "Read");
1459 out_clean:
1460         for (i = 0; i < ring_size; i++)
1461                 free_page((unsigned long)page[i]);
1462         if (crc) {
1463                 if (crc->thr)
1464                         kthread_stop(crc->thr);
1465                 kfree(crc);
1466         }
1467         if (data) {
1468                 for (thr = 0; thr < nr_threads; thr++)
1469                         if (data[thr].thr)
1470                                 kthread_stop(data[thr].thr);
1471                 vfree(data);
1472         }
1473         vfree(page);
1474 
1475         return ret;
1476 }
1477 
1478 /**
1479  *      swsusp_read - read the hibernation image.
1480  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1481  *                be written into this memory location
1482  */
1483 
1484 int swsusp_read(unsigned int *flags_p)
1485 {
1486         int error;
1487         struct swap_map_handle handle;
1488         struct snapshot_handle snapshot;
1489         struct swsusp_info *header;
1490 
1491         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1492         error = snapshot_write_next(&snapshot);
1493         if (error < PAGE_SIZE)
1494                 return error < 0 ? error : -EFAULT;
1495         header = (struct swsusp_info *)data_of(snapshot);
1496         error = get_swap_reader(&handle, flags_p);
1497         if (error)
1498                 goto end;
1499         if (!error)
1500                 error = swap_read_page(&handle, header, NULL);
1501         if (!error) {
1502                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1503                         load_image(&handle, &snapshot, header->pages - 1) :
1504                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1505         }
1506         swap_reader_finish(&handle);
1507 end:
1508         if (!error)
1509                 pr_debug("PM: Image successfully loaded\n");
1510         else
1511                 pr_debug("PM: Error %d resuming\n", error);
1512         return error;
1513 }
1514 
1515 /**
1516  *      swsusp_check - Check for swsusp signature in the resume device
1517  */
1518 
1519 int swsusp_check(void)
1520 {
1521         int error;
1522 
1523         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1524                                             FMODE_READ, NULL);
1525         if (!IS_ERR(hib_resume_bdev)) {
1526                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1527                 clear_page(swsusp_header);
1528                 error = hib_submit_io(READ_SYNC, swsusp_resume_block,
1529                                         swsusp_header, NULL);
1530                 if (error)
1531                         goto put;
1532 
1533                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1534                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1535                         /* Reset swap signature now */
1536                         error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
1537                                                 swsusp_header, NULL);
1538                 } else {
1539                         error = -EINVAL;
1540                 }
1541 
1542 put:
1543                 if (error)
1544                         blkdev_put(hib_resume_bdev, FMODE_READ);
1545                 else
1546                         pr_debug("PM: Image signature found, resuming\n");
1547         } else {
1548                 error = PTR_ERR(hib_resume_bdev);
1549         }
1550 
1551         if (error)
1552                 pr_debug("PM: Image not found (code %d)\n", error);
1553 
1554         return error;
1555 }
1556 
1557 /**
1558  *      swsusp_close - close swap device.
1559  */
1560 
1561 void swsusp_close(fmode_t mode)
1562 {
1563         if (IS_ERR(hib_resume_bdev)) {
1564                 pr_debug("PM: Image device not initialised\n");
1565                 return;
1566         }
1567 
1568         blkdev_put(hib_resume_bdev, mode);
1569 }
1570 
1571 /**
1572  *      swsusp_unmark - Unmark swsusp signature in the resume device
1573  */
1574 
1575 #ifdef CONFIG_SUSPEND
1576 int swsusp_unmark(void)
1577 {
1578         int error;
1579 
1580         hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
1581         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1582                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1583                 error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
1584                                         swsusp_header, NULL);
1585         } else {
1586                 printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
1587                 error = -ENODEV;
1588         }
1589 
1590         /*
1591          * We just returned from suspend, we don't need the image any more.
1592          */
1593         free_all_swap_pages(root_swap);
1594 
1595         return error;
1596 }
1597 #endif
1598 
1599 static int swsusp_header_init(void)
1600 {
1601         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1602         if (!swsusp_header)
1603                 panic("Could not allocate memory for swsusp_header\n");
1604         return 0;
1605 }
1606 
1607 core_initcall(swsusp_header_init);
1608 

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