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

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/kernel/power/swap.c
  4  *
  5  * This file provides functions for reading the suspend image from
  6  * and writing it to a swap partition.
  7  *
  8  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
  9  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
 10  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
 11  */
 12 
 13 #define pr_fmt(fmt) "PM: " fmt
 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 = rb_entry(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         blk_status_t            error;
229         struct blk_plug         plug;
230 };
231 
232 static void hib_init_batch(struct hib_bio_batch *hb)
233 {
234         atomic_set(&hb->count, 0);
235         init_waitqueue_head(&hb->wait);
236         hb->error = BLK_STS_OK;
237         blk_start_plug(&hb->plug);
238 }
239 
240 static void hib_finish_batch(struct hib_bio_batch *hb)
241 {
242         blk_finish_plug(&hb->plug);
243 }
244 
245 static void hib_end_io(struct bio *bio)
246 {
247         struct hib_bio_batch *hb = bio->bi_private;
248         struct page *page = bio_first_page_all(bio);
249 
250         if (bio->bi_status) {
251                 pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
252                          MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
253                          (unsigned long long)bio->bi_iter.bi_sector);
254         }
255 
256         if (bio_data_dir(bio) == WRITE)
257                 put_page(page);
258         else if (clean_pages_on_read)
259                 flush_icache_range((unsigned long)page_address(page),
260                                    (unsigned long)page_address(page) + PAGE_SIZE);
261 
262         if (bio->bi_status && !hb->error)
263                 hb->error = bio->bi_status;
264         if (atomic_dec_and_test(&hb->count))
265                 wake_up(&hb->wait);
266 
267         bio_put(bio);
268 }
269 
270 static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,
271                 struct hib_bio_batch *hb)
272 {
273         struct page *page = virt_to_page(addr);
274         struct bio *bio;
275         int error = 0;
276 
277         bio = bio_alloc(GFP_NOIO | __GFP_HIGH, 1);
278         bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
279         bio_set_dev(bio, hib_resume_bdev);
280         bio_set_op_attrs(bio, op, op_flags);
281 
282         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
283                 pr_err("Adding page to bio failed at %llu\n",
284                        (unsigned long long)bio->bi_iter.bi_sector);
285                 bio_put(bio);
286                 return -EFAULT;
287         }
288 
289         if (hb) {
290                 bio->bi_end_io = hib_end_io;
291                 bio->bi_private = hb;
292                 atomic_inc(&hb->count);
293                 submit_bio(bio);
294         } else {
295                 error = submit_bio_wait(bio);
296                 bio_put(bio);
297         }
298 
299         return error;
300 }
301 
302 static int hib_wait_io(struct hib_bio_batch *hb)
303 {
304         /*
305          * We are relying on the behavior of blk_plug that a thread with
306          * a plug will flush the plug list before sleeping.
307          */
308         wait_event(hb->wait, atomic_read(&hb->count) == 0);
309         return blk_status_to_errno(hb->error);
310 }
311 
312 /*
313  * Saving part
314  */
315 
316 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
317 {
318         int error;
319 
320         hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
321                       swsusp_header, NULL);
322         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
323             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
324                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
325                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
326                 swsusp_header->image = handle->first_sector;
327                 swsusp_header->flags = flags;
328                 if (flags & SF_CRC32_MODE)
329                         swsusp_header->crc32 = handle->crc32;
330                 error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
331                                       swsusp_resume_block, swsusp_header, NULL);
332         } else {
333                 pr_err("Swap header not found!\n");
334                 error = -ENODEV;
335         }
336         return error;
337 }
338 
339 /**
340  *      swsusp_swap_check - check if the resume device is a swap device
341  *      and get its index (if so)
342  *
343  *      This is called before saving image
344  */
345 static int swsusp_swap_check(void)
346 {
347         int res;
348 
349         if (swsusp_resume_device)
350                 res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
351         else
352                 res = find_first_swap(&swsusp_resume_device);
353         if (res < 0)
354                 return res;
355         root_swap = res;
356 
357         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
358                         NULL);
359         if (IS_ERR(hib_resume_bdev))
360                 return PTR_ERR(hib_resume_bdev);
361 
362         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
363         if (res < 0)
364                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
365 
366         return res;
367 }
368 
369 /**
370  *      write_page - Write one page to given swap location.
371  *      @buf:           Address we're writing.
372  *      @offset:        Offset of the swap page we're writing to.
373  *      @hb:            bio completion batch
374  */
375 
376 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
377 {
378         void *src;
379         int ret;
380 
381         if (!offset)
382                 return -ENOSPC;
383 
384         if (hb) {
385                 src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
386                                               __GFP_NORETRY);
387                 if (src) {
388                         copy_page(src, buf);
389                 } else {
390                         ret = hib_wait_io(hb); /* Free pages */
391                         if (ret)
392                                 return ret;
393                         src = (void *)__get_free_page(GFP_NOIO |
394                                                       __GFP_NOWARN |
395                                                       __GFP_NORETRY);
396                         if (src) {
397                                 copy_page(src, buf);
398                         } else {
399                                 WARN_ON_ONCE(1);
400                                 hb = NULL;      /* Go synchronous */
401                                 src = buf;
402                         }
403                 }
404         } else {
405                 src = buf;
406         }
407         return hib_submit_io(REQ_OP_WRITE, REQ_SYNC, offset, src, hb);
408 }
409 
410 static void release_swap_writer(struct swap_map_handle *handle)
411 {
412         if (handle->cur)
413                 free_page((unsigned long)handle->cur);
414         handle->cur = NULL;
415 }
416 
417 static int get_swap_writer(struct swap_map_handle *handle)
418 {
419         int ret;
420 
421         ret = swsusp_swap_check();
422         if (ret) {
423                 if (ret != -ENOSPC)
424                         pr_err("Cannot find swap device, try swapon -a\n");
425                 return ret;
426         }
427         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
428         if (!handle->cur) {
429                 ret = -ENOMEM;
430                 goto err_close;
431         }
432         handle->cur_swap = alloc_swapdev_block(root_swap);
433         if (!handle->cur_swap) {
434                 ret = -ENOSPC;
435                 goto err_rel;
436         }
437         handle->k = 0;
438         handle->reqd_free_pages = reqd_free_pages();
439         handle->first_sector = handle->cur_swap;
440         return 0;
441 err_rel:
442         release_swap_writer(handle);
443 err_close:
444         swsusp_close(FMODE_WRITE);
445         return ret;
446 }
447 
448 static int swap_write_page(struct swap_map_handle *handle, void *buf,
449                 struct hib_bio_batch *hb)
450 {
451         int error = 0;
452         sector_t offset;
453 
454         if (!handle->cur)
455                 return -EINVAL;
456         offset = alloc_swapdev_block(root_swap);
457         error = write_page(buf, offset, hb);
458         if (error)
459                 return error;
460         handle->cur->entries[handle->k++] = offset;
461         if (handle->k >= MAP_PAGE_ENTRIES) {
462                 offset = alloc_swapdev_block(root_swap);
463                 if (!offset)
464                         return -ENOSPC;
465                 handle->cur->next_swap = offset;
466                 error = write_page(handle->cur, handle->cur_swap, hb);
467                 if (error)
468                         goto out;
469                 clear_page(handle->cur);
470                 handle->cur_swap = offset;
471                 handle->k = 0;
472 
473                 if (hb && low_free_pages() <= handle->reqd_free_pages) {
474                         error = hib_wait_io(hb);
475                         if (error)
476                                 goto out;
477                         /*
478                          * Recalculate the number of required free pages, to
479                          * make sure we never take more than half.
480                          */
481                         handle->reqd_free_pages = reqd_free_pages();
482                 }
483         }
484  out:
485         return error;
486 }
487 
488 static int flush_swap_writer(struct swap_map_handle *handle)
489 {
490         if (handle->cur && handle->cur_swap)
491                 return write_page(handle->cur, handle->cur_swap, NULL);
492         else
493                 return -EINVAL;
494 }
495 
496 static int swap_writer_finish(struct swap_map_handle *handle,
497                 unsigned int flags, int error)
498 {
499         if (!error) {
500                 pr_info("S");
501                 error = mark_swapfiles(handle, flags);
502                 pr_cont("|\n");
503                 flush_swap_writer(handle);
504         }
505 
506         if (error)
507                 free_all_swap_pages(root_swap);
508         release_swap_writer(handle);
509         swsusp_close(FMODE_WRITE);
510 
511         return error;
512 }
513 
514 /* We need to remember how much compressed data we need to read. */
515 #define LZO_HEADER      sizeof(size_t)
516 
517 /* Number of pages/bytes we'll compress at one time. */
518 #define LZO_UNC_PAGES   32
519 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
520 
521 /* Number of pages/bytes we need for compressed data (worst case). */
522 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
523                                      LZO_HEADER, PAGE_SIZE)
524 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
525 
526 /* Maximum number of threads for compression/decompression. */
527 #define LZO_THREADS     3
528 
529 /* Minimum/maximum number of pages for read buffering. */
530 #define LZO_MIN_RD_PAGES        1024
531 #define LZO_MAX_RD_PAGES        8192
532 
533 
534 /**
535  *      save_image - save the suspend image data
536  */
537 
538 static int save_image(struct swap_map_handle *handle,
539                       struct snapshot_handle *snapshot,
540                       unsigned int nr_to_write)
541 {
542         unsigned int m;
543         int ret;
544         int nr_pages;
545         int err2;
546         struct hib_bio_batch hb;
547         ktime_t start;
548         ktime_t stop;
549 
550         hib_init_batch(&hb);
551 
552         pr_info("Saving image data pages (%u pages)...\n",
553                 nr_to_write);
554         m = nr_to_write / 10;
555         if (!m)
556                 m = 1;
557         nr_pages = 0;
558         start = ktime_get();
559         while (1) {
560                 ret = snapshot_read_next(snapshot);
561                 if (ret <= 0)
562                         break;
563                 ret = swap_write_page(handle, data_of(*snapshot), &hb);
564                 if (ret)
565                         break;
566                 if (!(nr_pages % m))
567                         pr_info("Image saving progress: %3d%%\n",
568                                 nr_pages / m * 10);
569                 nr_pages++;
570         }
571         err2 = hib_wait_io(&hb);
572         hib_finish_batch(&hb);
573         stop = ktime_get();
574         if (!ret)
575                 ret = err2;
576         if (!ret)
577                 pr_info("Image saving done\n");
578         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
579         return ret;
580 }
581 
582 /**
583  * Structure used for CRC32.
584  */
585 struct crc_data {
586         struct task_struct *thr;                  /* thread */
587         atomic_t ready;                           /* ready to start flag */
588         atomic_t stop;                            /* ready to stop flag */
589         unsigned run_threads;                     /* nr current threads */
590         wait_queue_head_t go;                     /* start crc update */
591         wait_queue_head_t done;                   /* crc update done */
592         u32 *crc32;                               /* points to handle's crc32 */
593         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
594         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
595 };
596 
597 /**
598  * CRC32 update function that runs in its own thread.
599  */
600 static int crc32_threadfn(void *data)
601 {
602         struct crc_data *d = data;
603         unsigned i;
604 
605         while (1) {
606                 wait_event(d->go, atomic_read(&d->ready) ||
607                                   kthread_should_stop());
608                 if (kthread_should_stop()) {
609                         d->thr = NULL;
610                         atomic_set(&d->stop, 1);
611                         wake_up(&d->done);
612                         break;
613                 }
614                 atomic_set(&d->ready, 0);
615 
616                 for (i = 0; i < d->run_threads; i++)
617                         *d->crc32 = crc32_le(*d->crc32,
618                                              d->unc[i], *d->unc_len[i]);
619                 atomic_set(&d->stop, 1);
620                 wake_up(&d->done);
621         }
622         return 0;
623 }
624 /**
625  * Structure used for LZO data compression.
626  */
627 struct cmp_data {
628         struct task_struct *thr;                  /* thread */
629         atomic_t ready;                           /* ready to start flag */
630         atomic_t stop;                            /* ready to stop flag */
631         int ret;                                  /* return code */
632         wait_queue_head_t go;                     /* start compression */
633         wait_queue_head_t done;                   /* compression done */
634         size_t unc_len;                           /* uncompressed length */
635         size_t cmp_len;                           /* compressed length */
636         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
637         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
638         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
639 };
640 
641 /**
642  * Compression function that runs in its own thread.
643  */
644 static int lzo_compress_threadfn(void *data)
645 {
646         struct cmp_data *d = data;
647 
648         while (1) {
649                 wait_event(d->go, atomic_read(&d->ready) ||
650                                   kthread_should_stop());
651                 if (kthread_should_stop()) {
652                         d->thr = NULL;
653                         d->ret = -1;
654                         atomic_set(&d->stop, 1);
655                         wake_up(&d->done);
656                         break;
657                 }
658                 atomic_set(&d->ready, 0);
659 
660                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
661                                           d->cmp + LZO_HEADER, &d->cmp_len,
662                                           d->wrk);
663                 atomic_set(&d->stop, 1);
664                 wake_up(&d->done);
665         }
666         return 0;
667 }
668 
669 /**
670  * save_image_lzo - Save the suspend image data compressed with LZO.
671  * @handle: Swap map handle to use for saving the image.
672  * @snapshot: Image to read data from.
673  * @nr_to_write: Number of pages to save.
674  */
675 static int save_image_lzo(struct swap_map_handle *handle,
676                           struct snapshot_handle *snapshot,
677                           unsigned int nr_to_write)
678 {
679         unsigned int m;
680         int ret = 0;
681         int nr_pages;
682         int err2;
683         struct hib_bio_batch hb;
684         ktime_t start;
685         ktime_t stop;
686         size_t off;
687         unsigned thr, run_threads, nr_threads;
688         unsigned char *page = NULL;
689         struct cmp_data *data = NULL;
690         struct crc_data *crc = NULL;
691 
692         hib_init_batch(&hb);
693 
694         /*
695          * We'll limit the number of threads for compression to limit memory
696          * footprint.
697          */
698         nr_threads = num_online_cpus() - 1;
699         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
700 
701         page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
702         if (!page) {
703                 pr_err("Failed to allocate LZO page\n");
704                 ret = -ENOMEM;
705                 goto out_clean;
706         }
707 
708         data = vmalloc(array_size(nr_threads, sizeof(*data)));
709         if (!data) {
710                 pr_err("Failed to allocate LZO data\n");
711                 ret = -ENOMEM;
712                 goto out_clean;
713         }
714         for (thr = 0; thr < nr_threads; thr++)
715                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
716 
717         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
718         if (!crc) {
719                 pr_err("Failed to allocate crc\n");
720                 ret = -ENOMEM;
721                 goto out_clean;
722         }
723         memset(crc, 0, offsetof(struct crc_data, go));
724 
725         /*
726          * Start the compression threads.
727          */
728         for (thr = 0; thr < nr_threads; thr++) {
729                 init_waitqueue_head(&data[thr].go);
730                 init_waitqueue_head(&data[thr].done);
731 
732                 data[thr].thr = kthread_run(lzo_compress_threadfn,
733                                             &data[thr],
734                                             "image_compress/%u", thr);
735                 if (IS_ERR(data[thr].thr)) {
736                         data[thr].thr = NULL;
737                         pr_err("Cannot start compression threads\n");
738                         ret = -ENOMEM;
739                         goto out_clean;
740                 }
741         }
742 
743         /*
744          * Start the CRC32 thread.
745          */
746         init_waitqueue_head(&crc->go);
747         init_waitqueue_head(&crc->done);
748 
749         handle->crc32 = 0;
750         crc->crc32 = &handle->crc32;
751         for (thr = 0; thr < nr_threads; thr++) {
752                 crc->unc[thr] = data[thr].unc;
753                 crc->unc_len[thr] = &data[thr].unc_len;
754         }
755 
756         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
757         if (IS_ERR(crc->thr)) {
758                 crc->thr = NULL;
759                 pr_err("Cannot start CRC32 thread\n");
760                 ret = -ENOMEM;
761                 goto out_clean;
762         }
763 
764         /*
765          * Adjust the number of required free pages after all allocations have
766          * been done. We don't want to run out of pages when writing.
767          */
768         handle->reqd_free_pages = reqd_free_pages();
769 
770         pr_info("Using %u thread(s) for compression\n", nr_threads);
771         pr_info("Compressing and saving image data (%u pages)...\n",
772                 nr_to_write);
773         m = nr_to_write / 10;
774         if (!m)
775                 m = 1;
776         nr_pages = 0;
777         start = ktime_get();
778         for (;;) {
779                 for (thr = 0; thr < nr_threads; thr++) {
780                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
781                                 ret = snapshot_read_next(snapshot);
782                                 if (ret < 0)
783                                         goto out_finish;
784 
785                                 if (!ret)
786                                         break;
787 
788                                 memcpy(data[thr].unc + off,
789                                        data_of(*snapshot), PAGE_SIZE);
790 
791                                 if (!(nr_pages % m))
792                                         pr_info("Image saving progress: %3d%%\n",
793                                                 nr_pages / m * 10);
794                                 nr_pages++;
795                         }
796                         if (!off)
797                                 break;
798 
799                         data[thr].unc_len = off;
800 
801                         atomic_set(&data[thr].ready, 1);
802                         wake_up(&data[thr].go);
803                 }
804 
805                 if (!thr)
806                         break;
807 
808                 crc->run_threads = thr;
809                 atomic_set(&crc->ready, 1);
810                 wake_up(&crc->go);
811 
812                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
813                         wait_event(data[thr].done,
814                                    atomic_read(&data[thr].stop));
815                         atomic_set(&data[thr].stop, 0);
816 
817                         ret = data[thr].ret;
818 
819                         if (ret < 0) {
820                                 pr_err("LZO compression failed\n");
821                                 goto out_finish;
822                         }
823 
824                         if (unlikely(!data[thr].cmp_len ||
825                                      data[thr].cmp_len >
826                                      lzo1x_worst_compress(data[thr].unc_len))) {
827                                 pr_err("Invalid LZO compressed length\n");
828                                 ret = -1;
829                                 goto out_finish;
830                         }
831 
832                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
833 
834                         /*
835                          * Given we are writing one page at a time to disk, we
836                          * copy that much from the buffer, although the last
837                          * bit will likely be smaller than full page. This is
838                          * OK - we saved the length of the compressed data, so
839                          * any garbage at the end will be discarded when we
840                          * read it.
841                          */
842                         for (off = 0;
843                              off < LZO_HEADER + data[thr].cmp_len;
844                              off += PAGE_SIZE) {
845                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
846 
847                                 ret = swap_write_page(handle, page, &hb);
848                                 if (ret)
849                                         goto out_finish;
850                         }
851                 }
852 
853                 wait_event(crc->done, atomic_read(&crc->stop));
854                 atomic_set(&crc->stop, 0);
855         }
856 
857 out_finish:
858         err2 = hib_wait_io(&hb);
859         stop = ktime_get();
860         if (!ret)
861                 ret = err2;
862         if (!ret)
863                 pr_info("Image saving done\n");
864         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
865 out_clean:
866         hib_finish_batch(&hb);
867         if (crc) {
868                 if (crc->thr)
869                         kthread_stop(crc->thr);
870                 kfree(crc);
871         }
872         if (data) {
873                 for (thr = 0; thr < nr_threads; thr++)
874                         if (data[thr].thr)
875                                 kthread_stop(data[thr].thr);
876                 vfree(data);
877         }
878         if (page) free_page((unsigned long)page);
879 
880         return ret;
881 }
882 
883 /**
884  *      enough_swap - Make sure we have enough swap to save the image.
885  *
886  *      Returns TRUE or FALSE after checking the total amount of swap
887  *      space available from the resume partition.
888  */
889 
890 static int enough_swap(unsigned int nr_pages)
891 {
892         unsigned int free_swap = count_swap_pages(root_swap, 1);
893         unsigned int required;
894 
895         pr_debug("Free swap pages: %u\n", free_swap);
896 
897         required = PAGES_FOR_IO + nr_pages;
898         return free_swap > required;
899 }
900 
901 /**
902  *      swsusp_write - Write entire image and metadata.
903  *      @flags: flags to pass to the "boot" kernel in the image header
904  *
905  *      It is important _NOT_ to umount filesystems at this point. We want
906  *      them synced (in case something goes wrong) but we DO not want to mark
907  *      filesystem clean: it is not. (And it does not matter, if we resume
908  *      correctly, we'll mark system clean, anyway.)
909  */
910 
911 int swsusp_write(unsigned int flags)
912 {
913         struct swap_map_handle handle;
914         struct snapshot_handle snapshot;
915         struct swsusp_info *header;
916         unsigned long pages;
917         int error;
918 
919         pages = snapshot_get_image_size();
920         error = get_swap_writer(&handle);
921         if (error) {
922                 pr_err("Cannot get swap writer\n");
923                 return error;
924         }
925         if (flags & SF_NOCOMPRESS_MODE) {
926                 if (!enough_swap(pages)) {
927                         pr_err("Not enough free swap\n");
928                         error = -ENOSPC;
929                         goto out_finish;
930                 }
931         }
932         memset(&snapshot, 0, sizeof(struct snapshot_handle));
933         error = snapshot_read_next(&snapshot);
934         if (error < (int)PAGE_SIZE) {
935                 if (error >= 0)
936                         error = -EFAULT;
937 
938                 goto out_finish;
939         }
940         header = (struct swsusp_info *)data_of(snapshot);
941         error = swap_write_page(&handle, header, NULL);
942         if (!error) {
943                 error = (flags & SF_NOCOMPRESS_MODE) ?
944                         save_image(&handle, &snapshot, pages - 1) :
945                         save_image_lzo(&handle, &snapshot, pages - 1);
946         }
947 out_finish:
948         error = swap_writer_finish(&handle, flags, error);
949         return error;
950 }
951 
952 /**
953  *      The following functions allow us to read data using a swap map
954  *      in a file-alike way
955  */
956 
957 static void release_swap_reader(struct swap_map_handle *handle)
958 {
959         struct swap_map_page_list *tmp;
960 
961         while (handle->maps) {
962                 if (handle->maps->map)
963                         free_page((unsigned long)handle->maps->map);
964                 tmp = handle->maps;
965                 handle->maps = handle->maps->next;
966                 kfree(tmp);
967         }
968         handle->cur = NULL;
969 }
970 
971 static int get_swap_reader(struct swap_map_handle *handle,
972                 unsigned int *flags_p)
973 {
974         int error;
975         struct swap_map_page_list *tmp, *last;
976         sector_t offset;
977 
978         *flags_p = swsusp_header->flags;
979 
980         if (!swsusp_header->image) /* how can this happen? */
981                 return -EINVAL;
982 
983         handle->cur = NULL;
984         last = handle->maps = NULL;
985         offset = swsusp_header->image;
986         while (offset) {
987                 tmp = kzalloc(sizeof(*handle->maps), GFP_KERNEL);
988                 if (!tmp) {
989                         release_swap_reader(handle);
990                         return -ENOMEM;
991                 }
992                 if (!handle->maps)
993                         handle->maps = tmp;
994                 if (last)
995                         last->next = tmp;
996                 last = tmp;
997 
998                 tmp->map = (struct swap_map_page *)
999                            __get_free_page(GFP_NOIO | __GFP_HIGH);
1000                 if (!tmp->map) {
1001                         release_swap_reader(handle);
1002                         return -ENOMEM;
1003                 }
1004 
1005                 error = hib_submit_io(REQ_OP_READ, 0, offset, tmp->map, NULL);
1006                 if (error) {
1007                         release_swap_reader(handle);
1008                         return error;
1009                 }
1010                 offset = tmp->map->next_swap;
1011         }
1012         handle->k = 0;
1013         handle->cur = handle->maps->map;
1014         return 0;
1015 }
1016 
1017 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1018                 struct hib_bio_batch *hb)
1019 {
1020         sector_t offset;
1021         int error;
1022         struct swap_map_page_list *tmp;
1023 
1024         if (!handle->cur)
1025                 return -EINVAL;
1026         offset = handle->cur->entries[handle->k];
1027         if (!offset)
1028                 return -EFAULT;
1029         error = hib_submit_io(REQ_OP_READ, 0, offset, buf, hb);
1030         if (error)
1031                 return error;
1032         if (++handle->k >= MAP_PAGE_ENTRIES) {
1033                 handle->k = 0;
1034                 free_page((unsigned long)handle->maps->map);
1035                 tmp = handle->maps;
1036                 handle->maps = handle->maps->next;
1037                 kfree(tmp);
1038                 if (!handle->maps)
1039                         release_swap_reader(handle);
1040                 else
1041                         handle->cur = handle->maps->map;
1042         }
1043         return error;
1044 }
1045 
1046 static int swap_reader_finish(struct swap_map_handle *handle)
1047 {
1048         release_swap_reader(handle);
1049 
1050         return 0;
1051 }
1052 
1053 /**
1054  *      load_image - load the image using the swap map handle
1055  *      @handle and the snapshot handle @snapshot
1056  *      (assume there are @nr_pages pages to load)
1057  */
1058 
1059 static int load_image(struct swap_map_handle *handle,
1060                       struct snapshot_handle *snapshot,
1061                       unsigned int nr_to_read)
1062 {
1063         unsigned int m;
1064         int ret = 0;
1065         ktime_t start;
1066         ktime_t stop;
1067         struct hib_bio_batch hb;
1068         int err2;
1069         unsigned nr_pages;
1070 
1071         hib_init_batch(&hb);
1072 
1073         clean_pages_on_read = true;
1074         pr_info("Loading image data pages (%u pages)...\n", nr_to_read);
1075         m = nr_to_read / 10;
1076         if (!m)
1077                 m = 1;
1078         nr_pages = 0;
1079         start = ktime_get();
1080         for ( ; ; ) {
1081                 ret = snapshot_write_next(snapshot);
1082                 if (ret <= 0)
1083                         break;
1084                 ret = swap_read_page(handle, data_of(*snapshot), &hb);
1085                 if (ret)
1086                         break;
1087                 if (snapshot->sync_read)
1088                         ret = hib_wait_io(&hb);
1089                 if (ret)
1090                         break;
1091                 if (!(nr_pages % m))
1092                         pr_info("Image loading progress: %3d%%\n",
1093                                 nr_pages / m * 10);
1094                 nr_pages++;
1095         }
1096         err2 = hib_wait_io(&hb);
1097         hib_finish_batch(&hb);
1098         stop = ktime_get();
1099         if (!ret)
1100                 ret = err2;
1101         if (!ret) {
1102                 pr_info("Image loading done\n");
1103                 snapshot_write_finalize(snapshot);
1104                 if (!snapshot_image_loaded(snapshot))
1105                         ret = -ENODATA;
1106         }
1107         swsusp_show_speed(start, stop, nr_to_read, "Read");
1108         return ret;
1109 }
1110 
1111 /**
1112  * Structure used for LZO data decompression.
1113  */
1114 struct dec_data {
1115         struct task_struct *thr;                  /* thread */
1116         atomic_t ready;                           /* ready to start flag */
1117         atomic_t stop;                            /* ready to stop flag */
1118         int ret;                                  /* return code */
1119         wait_queue_head_t go;                     /* start decompression */
1120         wait_queue_head_t done;                   /* decompression done */
1121         size_t unc_len;                           /* uncompressed length */
1122         size_t cmp_len;                           /* compressed length */
1123         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1124         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1125 };
1126 
1127 /**
1128  * Decompression function that runs in its own thread.
1129  */
1130 static int lzo_decompress_threadfn(void *data)
1131 {
1132         struct dec_data *d = data;
1133 
1134         while (1) {
1135                 wait_event(d->go, atomic_read(&d->ready) ||
1136                                   kthread_should_stop());
1137                 if (kthread_should_stop()) {
1138                         d->thr = NULL;
1139                         d->ret = -1;
1140                         atomic_set(&d->stop, 1);
1141                         wake_up(&d->done);
1142                         break;
1143                 }
1144                 atomic_set(&d->ready, 0);
1145 
1146                 d->unc_len = LZO_UNC_SIZE;
1147                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1148                                                d->unc, &d->unc_len);
1149                 if (clean_pages_on_decompress)
1150                         flush_icache_range((unsigned long)d->unc,
1151                                            (unsigned long)d->unc + d->unc_len);
1152 
1153                 atomic_set(&d->stop, 1);
1154                 wake_up(&d->done);
1155         }
1156         return 0;
1157 }
1158 
1159 /**
1160  * load_image_lzo - Load compressed image data and decompress them with LZO.
1161  * @handle: Swap map handle to use for loading data.
1162  * @snapshot: Image to copy uncompressed data into.
1163  * @nr_to_read: Number of pages to load.
1164  */
1165 static int load_image_lzo(struct swap_map_handle *handle,
1166                           struct snapshot_handle *snapshot,
1167                           unsigned int nr_to_read)
1168 {
1169         unsigned int m;
1170         int ret = 0;
1171         int eof = 0;
1172         struct hib_bio_batch hb;
1173         ktime_t start;
1174         ktime_t stop;
1175         unsigned nr_pages;
1176         size_t off;
1177         unsigned i, thr, run_threads, nr_threads;
1178         unsigned ring = 0, pg = 0, ring_size = 0,
1179                  have = 0, want, need, asked = 0;
1180         unsigned long read_pages = 0;
1181         unsigned char **page = NULL;
1182         struct dec_data *data = NULL;
1183         struct crc_data *crc = NULL;
1184 
1185         hib_init_batch(&hb);
1186 
1187         /*
1188          * We'll limit the number of threads for decompression to limit memory
1189          * footprint.
1190          */
1191         nr_threads = num_online_cpus() - 1;
1192         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1193 
1194         page = vmalloc(array_size(LZO_MAX_RD_PAGES, sizeof(*page)));
1195         if (!page) {
1196                 pr_err("Failed to allocate LZO page\n");
1197                 ret = -ENOMEM;
1198                 goto out_clean;
1199         }
1200 
1201         data = vmalloc(array_size(nr_threads, sizeof(*data)));
1202         if (!data) {
1203                 pr_err("Failed to allocate LZO data\n");
1204                 ret = -ENOMEM;
1205                 goto out_clean;
1206         }
1207         for (thr = 0; thr < nr_threads; thr++)
1208                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1209 
1210         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1211         if (!crc) {
1212                 pr_err("Failed to allocate crc\n");
1213                 ret = -ENOMEM;
1214                 goto out_clean;
1215         }
1216         memset(crc, 0, offsetof(struct crc_data, go));
1217 
1218         clean_pages_on_decompress = true;
1219 
1220         /*
1221          * Start the decompression threads.
1222          */
1223         for (thr = 0; thr < nr_threads; thr++) {
1224                 init_waitqueue_head(&data[thr].go);
1225                 init_waitqueue_head(&data[thr].done);
1226 
1227                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1228                                             &data[thr],
1229                                             "image_decompress/%u", thr);
1230                 if (IS_ERR(data[thr].thr)) {
1231                         data[thr].thr = NULL;
1232                         pr_err("Cannot start decompression threads\n");
1233                         ret = -ENOMEM;
1234                         goto out_clean;
1235                 }
1236         }
1237 
1238         /*
1239          * Start the CRC32 thread.
1240          */
1241         init_waitqueue_head(&crc->go);
1242         init_waitqueue_head(&crc->done);
1243 
1244         handle->crc32 = 0;
1245         crc->crc32 = &handle->crc32;
1246         for (thr = 0; thr < nr_threads; thr++) {
1247                 crc->unc[thr] = data[thr].unc;
1248                 crc->unc_len[thr] = &data[thr].unc_len;
1249         }
1250 
1251         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1252         if (IS_ERR(crc->thr)) {
1253                 crc->thr = NULL;
1254                 pr_err("Cannot start CRC32 thread\n");
1255                 ret = -ENOMEM;
1256                 goto out_clean;
1257         }
1258 
1259         /*
1260          * Set the number of pages for read buffering.
1261          * This is complete guesswork, because we'll only know the real
1262          * picture once prepare_image() is called, which is much later on
1263          * during the image load phase. We'll assume the worst case and
1264          * say that none of the image pages are from high memory.
1265          */
1266         if (low_free_pages() > snapshot_get_image_size())
1267                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1268         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1269 
1270         for (i = 0; i < read_pages; i++) {
1271                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1272                                                   GFP_NOIO | __GFP_HIGH :
1273                                                   GFP_NOIO | __GFP_NOWARN |
1274                                                   __GFP_NORETRY);
1275 
1276                 if (!page[i]) {
1277                         if (i < LZO_CMP_PAGES) {
1278                                 ring_size = i;
1279                                 pr_err("Failed to allocate LZO pages\n");
1280                                 ret = -ENOMEM;
1281                                 goto out_clean;
1282                         } else {
1283                                 break;
1284                         }
1285                 }
1286         }
1287         want = ring_size = i;
1288 
1289         pr_info("Using %u thread(s) for decompression\n", nr_threads);
1290         pr_info("Loading and decompressing image data (%u pages)...\n",
1291                 nr_to_read);
1292         m = nr_to_read / 10;
1293         if (!m)
1294                 m = 1;
1295         nr_pages = 0;
1296         start = ktime_get();
1297 
1298         ret = snapshot_write_next(snapshot);
1299         if (ret <= 0)
1300                 goto out_finish;
1301 
1302         for(;;) {
1303                 for (i = 0; !eof && i < want; i++) {
1304                         ret = swap_read_page(handle, page[ring], &hb);
1305                         if (ret) {
1306                                 /*
1307                                  * On real read error, finish. On end of data,
1308                                  * set EOF flag and just exit the read loop.
1309                                  */
1310                                 if (handle->cur &&
1311                                     handle->cur->entries[handle->k]) {
1312                                         goto out_finish;
1313                                 } else {
1314                                         eof = 1;
1315                                         break;
1316                                 }
1317                         }
1318                         if (++ring >= ring_size)
1319                                 ring = 0;
1320                 }
1321                 asked += i;
1322                 want -= i;
1323 
1324                 /*
1325                  * We are out of data, wait for some more.
1326                  */
1327                 if (!have) {
1328                         if (!asked)
1329                                 break;
1330 
1331                         ret = hib_wait_io(&hb);
1332                         if (ret)
1333                                 goto out_finish;
1334                         have += asked;
1335                         asked = 0;
1336                         if (eof)
1337                                 eof = 2;
1338                 }
1339 
1340                 if (crc->run_threads) {
1341                         wait_event(crc->done, atomic_read(&crc->stop));
1342                         atomic_set(&crc->stop, 0);
1343                         crc->run_threads = 0;
1344                 }
1345 
1346                 for (thr = 0; have && thr < nr_threads; thr++) {
1347                         data[thr].cmp_len = *(size_t *)page[pg];
1348                         if (unlikely(!data[thr].cmp_len ||
1349                                      data[thr].cmp_len >
1350                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1351                                 pr_err("Invalid LZO compressed length\n");
1352                                 ret = -1;
1353                                 goto out_finish;
1354                         }
1355 
1356                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1357                                             PAGE_SIZE);
1358                         if (need > have) {
1359                                 if (eof > 1) {
1360                                         ret = -1;
1361                                         goto out_finish;
1362                                 }
1363                                 break;
1364                         }
1365 
1366                         for (off = 0;
1367                              off < LZO_HEADER + data[thr].cmp_len;
1368                              off += PAGE_SIZE) {
1369                                 memcpy(data[thr].cmp + off,
1370                                        page[pg], PAGE_SIZE);
1371                                 have--;
1372                                 want++;
1373                                 if (++pg >= ring_size)
1374                                         pg = 0;
1375                         }
1376 
1377                         atomic_set(&data[thr].ready, 1);
1378                         wake_up(&data[thr].go);
1379                 }
1380 
1381                 /*
1382                  * Wait for more data while we are decompressing.
1383                  */
1384                 if (have < LZO_CMP_PAGES && asked) {
1385                         ret = hib_wait_io(&hb);
1386                         if (ret)
1387                                 goto out_finish;
1388                         have += asked;
1389                         asked = 0;
1390                         if (eof)
1391                                 eof = 2;
1392                 }
1393 
1394                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1395                         wait_event(data[thr].done,
1396                                    atomic_read(&data[thr].stop));
1397                         atomic_set(&data[thr].stop, 0);
1398 
1399                         ret = data[thr].ret;
1400 
1401                         if (ret < 0) {
1402                                 pr_err("LZO decompression failed\n");
1403                                 goto out_finish;
1404                         }
1405 
1406                         if (unlikely(!data[thr].unc_len ||
1407                                      data[thr].unc_len > LZO_UNC_SIZE ||
1408                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1409                                 pr_err("Invalid LZO uncompressed length\n");
1410                                 ret = -1;
1411                                 goto out_finish;
1412                         }
1413 
1414                         for (off = 0;
1415                              off < data[thr].unc_len; off += PAGE_SIZE) {
1416                                 memcpy(data_of(*snapshot),
1417                                        data[thr].unc + off, PAGE_SIZE);
1418 
1419                                 if (!(nr_pages % m))
1420                                         pr_info("Image loading progress: %3d%%\n",
1421                                                 nr_pages / m * 10);
1422                                 nr_pages++;
1423 
1424                                 ret = snapshot_write_next(snapshot);
1425                                 if (ret <= 0) {
1426                                         crc->run_threads = thr + 1;
1427                                         atomic_set(&crc->ready, 1);
1428                                         wake_up(&crc->go);
1429                                         goto out_finish;
1430                                 }
1431                         }
1432                 }
1433 
1434                 crc->run_threads = thr;
1435                 atomic_set(&crc->ready, 1);
1436                 wake_up(&crc->go);
1437         }
1438 
1439 out_finish:
1440         if (crc->run_threads) {
1441                 wait_event(crc->done, atomic_read(&crc->stop));
1442                 atomic_set(&crc->stop, 0);
1443         }
1444         stop = ktime_get();
1445         if (!ret) {
1446                 pr_info("Image loading done\n");
1447                 snapshot_write_finalize(snapshot);
1448                 if (!snapshot_image_loaded(snapshot))
1449                         ret = -ENODATA;
1450                 if (!ret) {
1451                         if (swsusp_header->flags & SF_CRC32_MODE) {
1452                                 if(handle->crc32 != swsusp_header->crc32) {
1453                                         pr_err("Invalid image CRC32!\n");
1454                                         ret = -ENODATA;
1455                                 }
1456                         }
1457                 }
1458         }
1459         swsusp_show_speed(start, stop, nr_to_read, "Read");
1460 out_clean:
1461         hib_finish_batch(&hb);
1462         for (i = 0; i < ring_size; i++)
1463                 free_page((unsigned long)page[i]);
1464         if (crc) {
1465                 if (crc->thr)
1466                         kthread_stop(crc->thr);
1467                 kfree(crc);
1468         }
1469         if (data) {
1470                 for (thr = 0; thr < nr_threads; thr++)
1471                         if (data[thr].thr)
1472                                 kthread_stop(data[thr].thr);
1473                 vfree(data);
1474         }
1475         vfree(page);
1476 
1477         return ret;
1478 }
1479 
1480 /**
1481  *      swsusp_read - read the hibernation image.
1482  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1483  *                be written into this memory location
1484  */
1485 
1486 int swsusp_read(unsigned int *flags_p)
1487 {
1488         int error;
1489         struct swap_map_handle handle;
1490         struct snapshot_handle snapshot;
1491         struct swsusp_info *header;
1492 
1493         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1494         error = snapshot_write_next(&snapshot);
1495         if (error < (int)PAGE_SIZE)
1496                 return error < 0 ? error : -EFAULT;
1497         header = (struct swsusp_info *)data_of(snapshot);
1498         error = get_swap_reader(&handle, flags_p);
1499         if (error)
1500                 goto end;
1501         if (!error)
1502                 error = swap_read_page(&handle, header, NULL);
1503         if (!error) {
1504                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1505                         load_image(&handle, &snapshot, header->pages - 1) :
1506                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1507         }
1508         swap_reader_finish(&handle);
1509 end:
1510         if (!error)
1511                 pr_debug("Image successfully loaded\n");
1512         else
1513                 pr_debug("Error %d resuming\n", error);
1514         return error;
1515 }
1516 
1517 /**
1518  *      swsusp_check - Check for swsusp signature in the resume device
1519  */
1520 
1521 int swsusp_check(void)
1522 {
1523         int error;
1524         void *holder;
1525 
1526         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1527                                             FMODE_READ | FMODE_EXCL, &holder);
1528         if (!IS_ERR(hib_resume_bdev)) {
1529                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1530                 clear_page(swsusp_header);
1531                 error = hib_submit_io(REQ_OP_READ, 0,
1532                                         swsusp_resume_block,
1533                                         swsusp_header, NULL);
1534                 if (error)
1535                         goto put;
1536 
1537                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1538                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1539                         /* Reset swap signature now */
1540                         error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1541                                                 swsusp_resume_block,
1542                                                 swsusp_header, NULL);
1543                 } else {
1544                         error = -EINVAL;
1545                 }
1546 
1547 put:
1548                 if (error)
1549                         blkdev_put(hib_resume_bdev, FMODE_READ | FMODE_EXCL);
1550                 else
1551                         pr_debug("Image signature found, resuming\n");
1552         } else {
1553                 error = PTR_ERR(hib_resume_bdev);
1554         }
1555 
1556         if (error)
1557                 pr_debug("Image not found (code %d)\n", error);
1558 
1559         return error;
1560 }
1561 
1562 /**
1563  *      swsusp_close - close swap device.
1564  */
1565 
1566 void swsusp_close(fmode_t mode)
1567 {
1568         if (IS_ERR(hib_resume_bdev)) {
1569                 pr_debug("Image device not initialised\n");
1570                 return;
1571         }
1572 
1573         blkdev_put(hib_resume_bdev, mode);
1574 }
1575 
1576 /**
1577  *      swsusp_unmark - Unmark swsusp signature in the resume device
1578  */
1579 
1580 #ifdef CONFIG_SUSPEND
1581 int swsusp_unmark(void)
1582 {
1583         int error;
1584 
1585         hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
1586                       swsusp_header, NULL);
1587         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1588                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1589                 error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1590                                         swsusp_resume_block,
1591                                         swsusp_header, NULL);
1592         } else {
1593                 pr_err("Cannot find swsusp signature!\n");
1594                 error = -ENODEV;
1595         }
1596 
1597         /*
1598          * We just returned from suspend, we don't need the image any more.
1599          */
1600         free_all_swap_pages(root_swap);
1601 
1602         return error;
1603 }
1604 #endif
1605 
1606 static int __init swsusp_header_init(void)
1607 {
1608         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1609         if (!swsusp_header)
1610                 panic("Could not allocate memory for swsusp_header\n");
1611         return 0;
1612 }
1613 
1614 core_initcall(swsusp_header_init);
1615 

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