kernel/kernel/power/swap.c

   1 /*
   2  * linux/kernel/power/swap.c
   3  *
   4  * This file provides functions for reading the suspend image from
   5  * and writing it to a swap partition.
   6  *
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
   8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
   9  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
  10  *
  11  * This file is released under the GPLv2.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/file.h>
  17 #include <linux/delay.h>
  18 #include <linux/bitops.h>
  19 #include <linux/genhd.h>
  20 #include <linux/device.h>
  21 #include <linux/bio.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/swap.h>
  24 #include <linux/swapops.h>
  25 #include <linux/pm.h>
  26 #include <linux/slab.h>
  27 #include <linux/lzo.h>
  28 #include <linux/vmalloc.h>
  29 #include <linux/cpumask.h>
  30 #include <linux/atomic.h>
  31 #include <linux/kthread.h>
  32 #include <linux/crc32.h>
  33 #include <linux/ktime.h>
  34
  35 #include "power.h"
  36
  37 #define HIBERNATE_SIG   "S1SUSPEND"
  38
  39 /*
  40  *      The swap map is a data structure used for keeping track of each page
  41  *      written to a swap partition.  It consists of many swap_map_page
  42  *      structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
  43  *      These structures are stored on the swap and linked together with the
  44  *      help of the .next_swap member.
  45  *
  46  *      The swap map is created during suspend.  The swap map pages are
  47  *      allocated and populated one at a time, so we only need one memory
  48  *      page to set up the entire structure.
  49  *
  50  *      During resume we pick up all swap_map_page structures into a list.
  51  */
  52
  53 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
  54
  55 /*
  56  * Number of free pages that are not high.
  57  */
  58 static inline unsigned long low_free_pages(void)
  59 {
  60         return nr_free_pages() - nr_free_highpages();
  61 }
  62
  63 /*
  64  * Number of pages required to be kept free while writing the image. Always
  65  * half of all available low pages before the writing starts.
  66  */
  67 static inline unsigned long reqd_free_pages(void)
  68 {
  69         return low_free_pages() / 2;
  70 }
  71
  72 struct swap_map_page {
  73         sector_t entries[MAP_PAGE_ENTRIES];
  74         sector_t next_swap;
  75 };
  76
  77 struct swap_map_page_list {
  78         struct swap_map_page *map;
  79         struct swap_map_page_list *next;
  80 };
  81
  82 /**
  83  *      The swap_map_handle structure is used for handling swap in
  84  *      a file-alike way
  85  */
  86
  87 struct swap_map_handle {
  88         struct swap_map_page *cur;
  89         struct swap_map_page_list *maps;
  90         sector_t cur_swap;
  91         sector_t first_sector;
  92         unsigned int k;
  93         unsigned long reqd_free_pages;
  94         u32 crc32;
  95 };
  96
  97 struct swsusp_header {
  98         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
  99                       sizeof(u32)];
 100         u32     crc32;
 101         sector_t image;
 102         unsigned int flags;     /* Flags to pass to the "boot" kernel */
 103         char    orig_sig[10];
 104         char    sig[10];
 105 } __packed;
 106
 107 static struct swsusp_header *swsusp_header;
 108
 109 /**
 110  *      The following functions are used for tracing the allocated
 111  *      swap pages, so that they can be freed in case of an error.
 112  */
 113
 114 struct swsusp_extent {
 115         struct rb_node node;
 116         unsigned long start;
 117         unsigned long end;
 118 };
 119
 120 static struct rb_root swsusp_extents = RB_ROOT;
 121
 122 static int swsusp_extents_insert(unsigned long swap_offset)
 123 {
 124         struct rb_node **new = &(swsusp_extents.rb_node);
 125         struct rb_node *parent = NULL;
 126         struct swsusp_extent *ext;
 127
 128         /* Figure out where to put the new node */
 129         while (*new) {
 130                 ext = rb_entry(*new, struct swsusp_extent, node);
 131                 parent = *new;
 132                 if (swap_offset < ext->start) {
 133                         /* Try to merge */
 134                         if (swap_offset == ext->start - 1) {
 135                                 ext->start--;
 136                                 return 0;
 137                         }
 138                         new = &((*new)->rb_left);
 139                 } else if (swap_offset > ext->end) {
 140                         /* Try to merge */
 141                         if (swap_offset == ext->end + 1) {
 142                                 ext->end++;
 143                                 return 0;
 144                         }
 145                         new = &((*new)->rb_right);
 146                 } else {
 147                         /* It already is in the tree */
 148                         return -EINVAL;
 149                 }
 150         }
 151         /* Add the new node and rebalance the tree. */
 152         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
 153         if (!ext)
 154                 return -ENOMEM;
 155
 156         ext->start = swap_offset;
 157         ext->end = swap_offset;
 158         rb_link_node(&ext->node, parent, new);
 159         rb_insert_color(&ext->node, &swsusp_extents);
 160         return 0;
 161 }
 162
 163 /**
 164  *      alloc_swapdev_block - allocate a swap page and register that it has
 165  *      been allocated, so that it can be freed in case of an error.
 166  */
 167
 168 sector_t alloc_swapdev_block(int swap)
 169 {
 170         unsigned long offset;
 171
 172         offset = swp_offset(get_swap_page_of_type(swap));
 173         if (offset) {
 174                 if (swsusp_extents_insert(offset))
 175                         swap_free(swp_entry(swap, offset));
 176                 else
 177                         return swapdev_block(swap, offset);
 178         }
 179         return 0;
 180 }
 181
 182 /**
 183  *      free_all_swap_pages - free swap pages allocated for saving image data.
 184  *      It also frees the extents used to register which swap entries had been
 185  *      allocated.
 186  */
 187
 188 void free_all_swap_pages(int swap)
 189 {
 190         struct rb_node *node;
 191
 192         while ((node = swsusp_extents.rb_node)) {
 193                 struct swsusp_extent *ext;
 194                 unsigned long offset;
 195
 196                 ext = container_of(node, struct swsusp_extent, node);
 197                 rb_erase(node, &swsusp_extents);
 198                 for (offset = ext->start; offset <= ext->end; offset++)
 199                         swap_free(swp_entry(swap, offset));
 200
 201                 kfree(ext);
 202         }
 203 }
 204
 205 int swsusp_swap_in_use(void)
 206 {
 207         return (swsusp_extents.rb_node != NULL);
 208 }
 209
 210 /*
 211  * General things
 212  */
 213
 214 static unsigned short root_swap = 0xffff;
 215 struct block_device *hib_resume_bdev;
 216
 217 /*
 218  * Saving part
 219  */
 220
 221 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 222 {
 223         int error;
 224
 225         hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
 226         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 227             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 228                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 229                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
 230                 swsusp_header->image = handle->first_sector;
 231                 swsusp_header->flags = flags;
 232                 if (flags & SF_CRC32_MODE)
 233                         swsusp_header->crc32 = handle->crc32;
 234                 error = hib_bio_write_page(swsusp_resume_block,
 235                                         swsusp_header, NULL);
 236         } else {
 237                 printk(KERN_ERR "PM: Swap header not found!\n");
 238                 error = -ENODEV;
 239         }
 240         return error;
 241 }
 242
 243 /**
 244  *      swsusp_swap_check - check if the resume device is a swap device
 245  *      and get its index (if so)
 246  *
 247  *      This is called before saving image
 248  */
 249 static int swsusp_swap_check(void)
 250 {
 251         int res;
 252
 253         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 254                         &hib_resume_bdev);
 255         if (res < 0)
 256                 return res;
 257
 258         root_swap = res;
 259         res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
 260         if (res)
 261                 return res;
 262
 263         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
 264         if (res < 0)
 265                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
 266
 267         return res;
 268 }
 269
 270 /**
 271  *      write_page - Write one page to given swap location.
 272  *      @buf:           Address we're writing.
 273  *      @offset:        Offset of the swap page we're writing to.
 274  *      @bio_chain:     Link the next write BIO here
 275  */
 276
 277 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 278 {
 279         void *src;
 280         int ret;
 281
 282         if (!offset)
 283                 return -ENOSPC;
 284
 285         if (bio_chain) {
 286                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
 287                                               __GFP_NORETRY);
 288                 if (src) {
 289                         copy_page(src, buf);
 290                 } else {
 291                         ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
 292                         if (ret)
 293                                 return ret;
 294                         src = (void *)__get_free_page(__GFP_WAIT |
 295                                                       __GFP_NOWARN |
 296                                                       __GFP_NORETRY);
 297                         if (src) {
 298                                 copy_page(src, buf);
 299                         } else {
 300                                 WARN_ON_ONCE(1);
 301                                 bio_chain = NULL;       /* Go synchronous */
 302                                 src = buf;
 303                         }
 304                 }
 305         } else {
 306                 src = buf;
 307         }
 308         return hib_bio_write_page(offset, src, bio_chain);
 309 }
 310
 311 static void release_swap_writer(struct swap_map_handle *handle)
 312 {
 313         if (handle->cur)
 314                 free_page((unsigned long)handle->cur);
 315         handle->cur = NULL;
 316 }
 317
 318 static int get_swap_writer(struct swap_map_handle *handle)
 319 {
 320         int ret;
 321
 322         ret = swsusp_swap_check();
 323         if (ret) {
 324                 if (ret != -ENOSPC)
 325                         printk(KERN_ERR "PM: Cannot find swap device, try "
 326                                         "swapon -a.\n");
 327                 return ret;
 328         }
 329         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 330         if (!handle->cur) {
 331                 ret = -ENOMEM;
 332                 goto err_close;
 333         }
 334         handle->cur_swap = alloc_swapdev_block(root_swap);
 335         if (!handle->cur_swap) {
 336                 ret = -ENOSPC;
 337                 goto err_rel;
 338         }
 339         handle->k = 0;
 340         handle->reqd_free_pages = reqd_free_pages();
 341         handle->first_sector = handle->cur_swap;
 342         return 0;
 343 err_rel:
 344         release_swap_writer(handle);
 345 err_close:
 346         swsusp_close(FMODE_WRITE);
 347         return ret;
 348 }
 349
 350 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 351                                 struct bio **bio_chain)
 352 {
 353         int error = 0;
 354         sector_t offset;
 355
 356         if (!handle->cur)
 357                 return -EINVAL;
 358         offset = alloc_swapdev_block(root_swap);
 359         error = write_page(buf, offset, bio_chain);
 360         if (error)
 361                 return error;
 362         handle->cur->entries[handle->k++] = offset;
 363         if (handle->k >= MAP_PAGE_ENTRIES) {
 364                 offset = alloc_swapdev_block(root_swap);
 365                 if (!offset)
 366                         return -ENOSPC;
 367                 handle->cur->next_swap = offset;
 368                 error = write_page(handle->cur, handle->cur_swap, bio_chain);
 369                 if (error)
 370                         goto out;
 371                 clear_page(handle->cur);
 372                 handle->cur_swap = offset;
 373                 handle->k = 0;
 374
 375                 if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
 376                         error = hib_wait_on_bio_chain(bio_chain);
 377                         if (error)
 378                                 goto out;
 379                         /*
 380                          * Recalculate the number of required free pages, to
 381                          * make sure we never take more than half.
 382                          */
 383                         handle->reqd_free_pages = reqd_free_pages();
 384                 }
 385         }
 386  out:
 387         return error;
 388 }
 389
 390 static int flush_swap_writer(struct swap_map_handle *handle)
 391 {
 392         if (handle->cur && handle->cur_swap)
 393                 return write_page(handle->cur, handle->cur_swap, NULL);
 394         else
 395                 return -EINVAL;
 396 }
 397
 398 static int swap_writer_finish(struct swap_map_handle *handle,
 399                 unsigned int flags, int error)
 400 {
 401         if (!error) {
 402                 flush_swap_writer(handle);
 403                 printk(KERN_INFO "PM: S");
 404                 error = mark_swapfiles(handle, flags);
 405                 printk("|\n");
 406         }
 407
 408         if (error)
 409                 free_all_swap_pages(root_swap);
 410         release_swap_writer(handle);
 411         swsusp_close(FMODE_WRITE);
 412
 413         return error;
 414 }
 415
 416 /* We need to remember how much compressed data we need to read. */
 417 #define LZO_HEADER      sizeof(size_t)
 418
 419 /* Number of pages/bytes we'll compress at one time. */
 420 #define LZO_UNC_PAGES   32
 421 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
 422
 423 /* Number of pages/bytes we need for compressed data (worst case). */
 424 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
 425                                      LZO_HEADER, PAGE_SIZE)
 426 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
 427
 428 /* Maximum number of threads for compression/decompression. */
 429 #define LZO_THREADS     3
 430
 431 /* Minimum/maximum number of pages for read buffering. */
 432 #define LZO_MIN_RD_PAGES        1024
 433 #define LZO_MAX_RD_PAGES        8192
 434
 435
 436 /**
 437  *      save_image - save the suspend image data
 438  */
 439
 440 static int save_image(struct swap_map_handle *handle,
 441                       struct snapshot_handle *snapshot,
 442                       unsigned int nr_to_write)
 443 {
 444         unsigned int m;
 445         int ret;
 446         int nr_pages;
 447         int err2;
 448         struct bio *bio;
 449         ktime_t start;
 450         ktime_t stop;
 451
 452         printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
 453                 nr_to_write);
 454         m = nr_to_write / 10;
 455         if (!m)
 456                 m = 1;
 457         nr_pages = 0;
 458         bio = NULL;
 459         start = ktime_get();
 460         while (1) {
 461                 ret = snapshot_read_next(snapshot);
 462                 if (ret <= 0)
 463                         break;
 464                 ret = swap_write_page(handle, data_of(*snapshot), &bio);
 465                 if (ret)
 466                         break;
 467                 if (!(nr_pages % m))
 468                         printk(KERN_INFO "PM: Image saving progress: %3d%%\n",
 469                                nr_pages / m * 10);
 470                 nr_pages++;
 471         }
 472         err2 = hib_wait_on_bio_chain(&bio);
 473         stop = ktime_get();
 474         if (!ret)
 475                 ret = err2;
 476         if (!ret)
 477                 printk(KERN_INFO "PM: Image saving done.\n");
 478         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 479         return ret;
 480 }
 481
 482 /**
 483  * Structure used for CRC32.
 484  */
 485 struct crc_data {
 486         struct task_struct *thr;                  /* thread */
 487         atomic_t ready;                           /* ready to start flag */
 488         atomic_t stop;                            /* ready to stop flag */
 489         unsigned run_threads;                     /* nr current threads */
 490         wait_queue_head_t go;                     /* start crc update */
 491         wait_queue_head_t done;                   /* crc update done */
 492         u32 *crc32;                               /* points to handle's crc32 */
 493         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
 494         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
 495 };
 496
 497 /**
 498  * CRC32 update function that runs in its own thread.
 499  */
 500 static int crc32_threadfn(void *data)
 501 {
 502         struct crc_data *d = data;
 503         unsigned i;
 504
 505         while (1) {
 506                 wait_event(d->go, atomic_read(&d->ready) ||
 507                                   kthread_should_stop());
 508                 if (kthread_should_stop()) {
 509                         d->thr = NULL;
 510                         atomic_set(&d->stop, 1);
 511                         wake_up(&d->done);
 512                         break;
 513                 }
 514                 atomic_set(&d->ready, 0);
 515
 516                 for (i = 0; i < d->run_threads; i++)
 517                         *d->crc32 = crc32_le(*d->crc32,
 518                                              d->unc[i], *d->unc_len[i]);
 519                 atomic_set(&d->stop, 1);
 520                 wake_up(&d->done);
 521         }
 522         return 0;
 523 }
 524 /**
 525  * Structure used for LZO data compression.
 526  */
 527 struct cmp_data {
 528         struct task_struct *thr;                  /* thread */
 529         atomic_t ready;                           /* ready to start flag */
 530         atomic_t stop;                            /* ready to stop flag */
 531         int ret;                                  /* return code */
 532         wait_queue_head_t go;                     /* start compression */
 533         wait_queue_head_t done;                   /* compression done */
 534         size_t unc_len;                           /* uncompressed length */
 535         size_t cmp_len;                           /* compressed length */
 536         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
 537         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
 538         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
 539 };
 540
 541 /**
 542  * Compression function that runs in its own thread.
 543  */
 544 static int lzo_compress_threadfn(void *data)
 545 {
 546         struct cmp_data *d = data;
 547
 548         while (1) {
 549                 wait_event(d->go, atomic_read(&d->ready) ||
 550                                   kthread_should_stop());
 551                 if (kthread_should_stop()) {
 552                         d->thr = NULL;
 553                         d->ret = -1;
 554                         atomic_set(&d->stop, 1);
 555                         wake_up(&d->done);
 556                         break;
 557                 }
 558                 atomic_set(&d->ready, 0);
 559
 560                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
 561                                           d->cmp + LZO_HEADER, &d->cmp_len,
 562                                           d->wrk);
 563                 atomic_set(&d->stop, 1);
 564                 wake_up(&d->done);
 565         }
 566         return 0;
 567 }
 568
 569 /**
 570  * save_image_lzo - Save the suspend image data compressed with LZO.
 571  * @handle: Swap map handle to use for saving the image.
 572  * @snapshot: Image to read data from.
 573  * @nr_to_write: Number of pages to save.
 574  */
 575 static int save_image_lzo(struct swap_map_handle *handle,
 576                           struct snapshot_handle *snapshot,
 577                           unsigned int nr_to_write)
 578 {
 579         unsigned int m;
 580         int ret = 0;
 581         int nr_pages;
 582         int err2;
 583         struct bio *bio;
 584         ktime_t start;
 585         ktime_t stop;
 586         size_t off;
 587         unsigned thr, run_threads, nr_threads;
 588         unsigned char *page = NULL;
 589         struct cmp_data *data = NULL;
 590         struct crc_data *crc = NULL;
 591
 592         /*
 593          * We'll limit the number of threads for compression to limit memory
 594          * footprint.
 595          */
 596         nr_threads = num_online_cpus() - 1;
 597         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 598
 599         page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 600         if (!page) {
 601                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
 602                 ret = -ENOMEM;
 603                 goto out_clean;
 604         }
 605
 606         data = vmalloc(sizeof(*data) * nr_threads);
 607         if (!data) {
 608                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
 609                 ret = -ENOMEM;
 610                 goto out_clean;
 611         }
 612         for (thr = 0; thr < nr_threads; thr++)
 613                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
 614
 615         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
 616         if (!crc) {
 617                 printk(KERN_ERR "PM: Failed to allocate crc\n");
 618                 ret = -ENOMEM;
 619                 goto out_clean;
 620         }
 621         memset(crc, 0, offsetof(struct crc_data, go));
 622
 623         /*
 624          * Start the compression threads.
 625          */
 626         for (thr = 0; thr < nr_threads; thr++) {
 627                 init_waitqueue_head(&data[thr].go);
 628                 init_waitqueue_head(&data[thr].done);
 629
 630                 data[thr].thr = kthread_run(lzo_compress_threadfn,
 631                                             &data[thr],
 632                                             "image_compress/%u", thr);
 633                 if (IS_ERR(data[thr].thr)) {
 634                         data[thr].thr = NULL;
 635                         printk(KERN_ERR
 636                                "PM: Cannot start compression threads\n");
 637                         ret = -ENOMEM;
 638                         goto out_clean;
 639                 }
 640         }
 641
 642         /*
 643          * Start the CRC32 thread.
 644          */
 645         init_waitqueue_head(&crc->go);
 646         init_waitqueue_head(&crc->done);
 647
 648         handle->crc32 = 0;
 649         crc->crc32 = &handle->crc32;
 650         for (thr = 0; thr < nr_threads; thr++) {
 651                 crc->unc[thr] = data[thr].unc;
 652                 crc->unc_len[thr] = &data[thr].unc_len;
 653         }
 654
 655         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
 656         if (IS_ERR(crc->thr)) {
 657                 crc->thr = NULL;
 658                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
 659                 ret = -ENOMEM;
 660                 goto out_clean;
 661         }
 662
 663         /*
 664          * Adjust the number of required free pages after all allocations have
 665          * been done. We don't want to run out of pages when writing.
 666          */
 667         handle->reqd_free_pages = reqd_free_pages();
 668
 669         printk(KERN_INFO
 670                 "PM: Using %u thread(s) for compression.\n"
 671                 "PM: Compressing and saving image data (%u pages)...\n",
 672                 nr_threads, nr_to_write);
 673         m = nr_to_write / 10;
 674         if (!m)
 675                 m = 1;
 676         nr_pages = 0;
 677         bio = NULL;
 678         start = ktime_get();
 679         for (;;) {
 680                 for (thr = 0; thr < nr_threads; thr++) {
 681                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
 682                                 ret = snapshot_read_next(snapshot);
 683                                 if (ret < 0)
 684                                         goto out_finish;
 685
 686                                 if (!ret)
 687                                         break;
 688
 689                                 memcpy(data[thr].unc + off,
 690                                        data_of(*snapshot), PAGE_SIZE);
 691
 692                                 if (!(nr_pages % m))
 693                                         printk(KERN_INFO
 694                                                "PM: Image saving progress: "
 695                                                "%3d%%\n",
 696                                                nr_pages / m * 10);
 697                                 nr_pages++;
 698                         }
 699                         if (!off)
 700                                 break;
 701
 702                         data[thr].unc_len = off;
 703
 704                         atomic_set(&data[thr].ready, 1);
 705                         wake_up(&data[thr].go);
 706                 }
 707
 708                 if (!thr)
 709                         break;
 710
 711                 crc->run_threads = thr;
 712                 atomic_set(&crc->ready, 1);
 713                 wake_up(&crc->go);
 714
 715                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
 716                         wait_event(data[thr].done,
 717                                    atomic_read(&data[thr].stop));
 718                         atomic_set(&data[thr].stop, 0);
 719
 720                         ret = data[thr].ret;
 721
 722                         if (ret < 0) {
 723                                 printk(KERN_ERR "PM: LZO compression failed\n");
 724                                 goto out_finish;
 725                         }
 726
 727                         if (unlikely(!data[thr].cmp_len ||
 728                                      data[thr].cmp_len >
 729                                      lzo1x_worst_compress(data[thr].unc_len))) {
 730                                 printk(KERN_ERR
 731                                        "PM: Invalid LZO compressed length\n");
 732                                 ret = -1;
 733                                 goto out_finish;
 734                         }
 735
 736                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
 737
 738                         /*
 739                          * Given we are writing one page at a time to disk, we
 740                          * copy that much from the buffer, although the last
 741                          * bit will likely be smaller than full page. This is
 742                          * OK - we saved the length of the compressed data, so
 743                          * any garbage at the end will be discarded when we
 744                          * read it.
 745                          */
 746                         for (off = 0;
 747                              off < LZO_HEADER + data[thr].cmp_len;
 748                              off += PAGE_SIZE) {
 749                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
 750
 751                                 ret = swap_write_page(handle, page, &bio);
 752                                 if (ret)
 753                                         goto out_finish;
 754                         }
 755                 }
 756
 757                 wait_event(crc->done, atomic_read(&crc->stop));
 758                 atomic_set(&crc->stop, 0);
 759         }
 760
 761 out_finish:
 762         err2 = hib_wait_on_bio_chain(&bio);
 763         stop = ktime_get();
 764         if (!ret)
 765                 ret = err2;
 766         if (!ret)
 767                 printk(KERN_INFO "PM: Image saving done.\n");
 768         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 769 out_clean:
 770         if (crc) {
 771                 if (crc->thr)
 772                         kthread_stop(crc->thr);
 773                 kfree(crc);
 774         }
 775         if (data) {
 776                 for (thr = 0; thr < nr_threads; thr++)
 777                         if (data[thr].thr)
 778                                 kthread_stop(data[thr].thr);
 779                 vfree(data);
 780         }
 781         if (page) free_page((unsigned long)page);
 782
 783         return ret;
 784 }
 785
 786 /**
 787  *      enough_swap - Make sure we have enough swap to save the image.
 788  *
 789  *      Returns TRUE or FALSE after checking the total amount of swap
 790  *      space avaiable from the resume partition.
 791  */
 792
 793 static int enough_swap(unsigned int nr_pages, unsigned int flags)
 794 {
 795         unsigned int free_swap = count_swap_pages(root_swap, 1);
 796         unsigned int required;
 797
 798         pr_debug("PM: Free swap pages: %u\n", free_swap);
 799
 800         required = PAGES_FOR_IO + nr_pages;
 801         return free_swap > required;
 802 }
 803
 804 /**
 805  *      swsusp_write - Write entire image and metadata.
 806  *      @flags: flags to pass to the "boot" kernel in the image header
 807  *
 808  *      It is important _NOT_ to umount filesystems at this point. We want
 809  *      them synced (in case something goes wrong) but we DO not want to mark
 810  *      filesystem clean: it is not. (And it does not matter, if we resume
 811  *      correctly, we'll mark system clean, anyway.)
 812  */
 813
 814 int swsusp_write(unsigned int flags)
 815 {
 816         struct swap_map_handle handle;
 817         struct snapshot_handle snapshot;
 818         struct swsusp_info *header;
 819         unsigned long pages;
 820         int error;
 821
 822         pages = snapshot_get_image_size();
 823         error = get_swap_writer(&handle);
 824         if (error) {
 825                 printk(KERN_ERR "PM: Cannot get swap writer\n");
 826                 return error;
 827         }
 828         if (flags & SF_NOCOMPRESS_MODE) {
 829                 if (!enough_swap(pages, flags)) {
 830                         printk(KERN_ERR "PM: Not enough free swap\n");
 831                         error = -ENOSPC;
 832                         goto out_finish;
 833                 }
 834         }
 835         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 836         error = snapshot_read_next(&snapshot);
 837         if (error < PAGE_SIZE) {
 838                 if (error >= 0)
 839                         error = -EFAULT;
 840
 841                 goto out_finish;
 842         }
 843         header = (struct swsusp_info *)data_of(snapshot);
 844         error = swap_write_page(&handle, header, NULL);
 845         if (!error) {
 846                 error = (flags & SF_NOCOMPRESS_MODE) ?
 847                         save_image(&handle, &snapshot, pages - 1) :
 848                         save_image_lzo(&handle, &snapshot, pages - 1);
 849         }
 850 out_finish:
 851         error = swap_writer_finish(&handle, flags, error);
 852         return error;
 853 }
 854
 855 /**
 856  *      The following functions allow us to read data using a swap map
 857  *      in a file-alike way
 858  */
 859
 860 static void release_swap_reader(struct swap_map_handle *handle)
 861 {
 862         struct swap_map_page_list *tmp;
 863
 864         while (handle->maps) {
 865                 if (handle->maps->map)
 866                         free_page((unsigned long)handle->maps->map);
 867                 tmp = handle->maps;
 868                 handle->maps = handle->maps->next;
 869                 kfree(tmp);
 870         }
 871         handle->cur = NULL;
 872 }
 873
 874 static int get_swap_reader(struct swap_map_handle *handle,
 875                 unsigned int *flags_p)
 876 {
 877         int error;
 878         struct swap_map_page_list *tmp, *last;
 879         sector_t offset;
 880
 881         *flags_p = swsusp_header->flags;
 882
 883         if (!swsusp_header->image) /* how can this happen? */
 884                 return -EINVAL;
 885
 886         handle->cur = NULL;
 887         last = handle->maps = NULL;
 888         offset = swsusp_header->image;
 889         while (offset) {
 890                 tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
 891                 if (!tmp) {
 892                         release_swap_reader(handle);
 893                         return -ENOMEM;
 894                 }
 895                 memset(tmp, 0, sizeof(*tmp));
 896                 if (!handle->maps)
 897                         handle->maps = tmp;
 898                 if (last)
 899                         last->next = tmp;
 900                 last = tmp;
 901
 902                 tmp->map = (struct swap_map_page *)
 903                            __get_free_page(__GFP_WAIT | __GFP_HIGH);
 904                 if (!tmp->map) {
 905                         release_swap_reader(handle);
 906                         return -ENOMEM;
 907                 }
 908
 909                 error = hib_bio_read_page(offset, tmp->map, NULL);
 910                 if (error) {
 911                         release_swap_reader(handle);
 912                         return error;
 913                 }
 914                 offset = tmp->map->next_swap;
 915         }
 916         handle->k = 0;
 917         handle->cur = handle->maps->map;
 918         return 0;
 919 }
 920
 921 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 922                                 struct bio **bio_chain)
 923 {
 924         sector_t offset;
 925         int error;
 926         struct swap_map_page_list *tmp;
 927
 928         if (!handle->cur)
 929                 return -EINVAL;
 930         offset = handle->cur->entries[handle->k];
 931         if (!offset)
 932                 return -EFAULT;
 933         error = hib_bio_read_page(offset, buf, bio_chain);
 934         if (error)
 935                 return error;
 936         if (++handle->k >= MAP_PAGE_ENTRIES) {
 937                 handle->k = 0;
 938                 free_page((unsigned long)handle->maps->map);
 939                 tmp = handle->maps;
 940                 handle->maps = handle->maps->next;
 941                 kfree(tmp);
 942                 if (!handle->maps)
 943                         release_swap_reader(handle);
 944                 else
 945                         handle->cur = handle->maps->map;
 946         }
 947         return error;
 948 }
 949
 950 static int swap_reader_finish(struct swap_map_handle *handle)
 951 {
 952         release_swap_reader(handle);
 953
 954         return 0;
 955 }
 956
 957 /**
 958  *      load_image - load the image using the swap map handle
 959  *      @handle and the snapshot handle @snapshot
 960  *      (assume there are @nr_pages pages to load)
 961  */
 962
 963 static int load_image(struct swap_map_handle *handle,
 964                       struct snapshot_handle *snapshot,
 965                       unsigned int nr_to_read)
 966 {
 967         unsigned int m;
 968         int ret = 0;
 969         ktime_t start;
 970         ktime_t stop;
 971         struct bio *bio;
 972         int err2;
 973         unsigned nr_pages;
 974
 975         printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
 976                 nr_to_read);
 977         m = nr_to_read / 10;
 978         if (!m)
 979                 m = 1;
 980         nr_pages = 0;
 981         bio = NULL;
 982         start = ktime_get();
 983         for ( ; ; ) {
 984                 ret = snapshot_write_next(snapshot);
 985                 if (ret <= 0)
 986                         break;
 987                 ret = swap_read_page(handle, data_of(*snapshot), &bio);
 988                 if (ret)
 989                         break;
 990                 if (snapshot->sync_read)
 991                         ret = hib_wait_on_bio_chain(&bio);
 992                 if (ret)
 993                         break;
 994                 if (!(nr_pages % m))
 995                         printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
 996                                nr_pages / m * 10);
 997                 nr_pages++;
 998         }
 999         err2 = hib_wait_on_bio_chain(&bio);
1000         stop = ktime_get();
1001         if (!ret)
1002                 ret = err2;
1003         if (!ret) {
1004                 printk(KERN_INFO "PM: Image loading done.\n");
1005                 snapshot_write_finalize(snapshot);
1006                 if (!snapshot_image_loaded(snapshot))
1007                         ret = -ENODATA;
1008         }
1009         swsusp_show_speed(start, stop, nr_to_read, "Read");
1010         return ret;
1011 }
1012
1013 /**
1014  * Structure used for LZO data decompression.
1015  */
1016 struct dec_data {
1017         struct task_struct *thr;                  /* thread */
1018         atomic_t ready;                           /* ready to start flag */
1019         atomic_t stop;                            /* ready to stop flag */
1020         int ret;                                  /* return code */
1021         wait_queue_head_t go;                     /* start decompression */
1022         wait_queue_head_t done;                   /* decompression done */
1023         size_t unc_len;                           /* uncompressed length */
1024         size_t cmp_len;                           /* compressed length */
1025         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1026         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1027 };
1028
1029 /**
1030  * Deompression function that runs in its own thread.
1031  */
1032 static int lzo_decompress_threadfn(void *data)
1033 {
1034         struct dec_data *d = data;
1035
1036         while (1) {
1037                 wait_event(d->go, atomic_read(&d->ready) ||
1038                                   kthread_should_stop());
1039                 if (kthread_should_stop()) {
1040                         d->thr = NULL;
1041                         d->ret = -1;
1042                         atomic_set(&d->stop, 1);
1043                         wake_up(&d->done);
1044                         break;
1045                 }
1046                 atomic_set(&d->ready, 0);
1047
1048                 d->unc_len = LZO_UNC_SIZE;
1049                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1050                                                d->unc, &d->unc_len);
1051                 atomic_set(&d->stop, 1);
1052                 wake_up(&d->done);
1053         }
1054         return 0;
1055 }
1056
1057 /**
1058  * load_image_lzo - Load compressed image data and decompress them with LZO.
1059  * @handle: Swap map handle to use for loading data.
1060  * @snapshot: Image to copy uncompressed data into.
1061  * @nr_to_read: Number of pages to load.
1062  */
1063 static int load_image_lzo(struct swap_map_handle *handle,
1064                           struct snapshot_handle *snapshot,
1065                           unsigned int nr_to_read)
1066 {
1067         unsigned int m;
1068         int ret = 0;
1069         int eof = 0;
1070         struct bio *bio;
1071         ktime_t start;
1072         ktime_t stop;
1073         unsigned nr_pages;
1074         size_t off;
1075         unsigned i, thr, run_threads, nr_threads;
1076         unsigned ring = 0, pg = 0, ring_size = 0,
1077                  have = 0, want, need, asked = 0;
1078         unsigned long read_pages = 0;
1079         unsigned char **page = NULL;
1080         struct dec_data *data = NULL;
1081         struct crc_data *crc = NULL;
1082
1083         /*
1084          * We'll limit the number of threads for decompression to limit memory
1085          * footprint.
1086          */
1087         nr_threads = num_online_cpus() - 1;
1088         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1089
1090         page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1091         if (!page) {
1092                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1093                 ret = -ENOMEM;
1094                 goto out_clean;
1095         }
1096
1097         data = vmalloc(sizeof(*data) * nr_threads);
1098         if (!data) {
1099                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1100                 ret = -ENOMEM;
1101                 goto out_clean;
1102         }
1103         for (thr = 0; thr < nr_threads; thr++)
1104                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1105
1106         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1107         if (!crc) {
1108                 printk(KERN_ERR "PM: Failed to allocate crc\n");
1109                 ret = -ENOMEM;
1110                 goto out_clean;
1111         }
1112         memset(crc, 0, offsetof(struct crc_data, go));
1113
1114         /*
1115          * Start the decompression threads.
1116          */
1117         for (thr = 0; thr < nr_threads; thr++) {
1118                 init_waitqueue_head(&data[thr].go);
1119                 init_waitqueue_head(&data[thr].done);
1120
1121                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1122                                             &data[thr],
1123                                             "image_decompress/%u", thr);
1124                 if (IS_ERR(data[thr].thr)) {
1125                         data[thr].thr = NULL;
1126                         printk(KERN_ERR
1127                                "PM: Cannot start decompression threads\n");
1128                         ret = -ENOMEM;
1129                         goto out_clean;
1130                 }
1131         }
1132
1133         /*
1134          * Start the CRC32 thread.
1135          */
1136         init_waitqueue_head(&crc->go);
1137         init_waitqueue_head(&crc->done);
1138
1139         handle->crc32 = 0;
1140         crc->crc32 = &handle->crc32;
1141         for (thr = 0; thr < nr_threads; thr++) {
1142                 crc->unc[thr] = data[thr].unc;
1143                 crc->unc_len[thr] = &data[thr].unc_len;
1144         }
1145
1146         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1147         if (IS_ERR(crc->thr)) {
1148                 crc->thr = NULL;
1149                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1150                 ret = -ENOMEM;
1151                 goto out_clean;
1152         }
1153
1154         /*
1155          * Set the number of pages for read buffering.
1156          * This is complete guesswork, because we'll only know the real
1157          * picture once prepare_image() is called, which is much later on
1158          * during the image load phase. We'll assume the worst case and
1159          * say that none of the image pages are from high memory.
1160          */
1161         if (low_free_pages() > snapshot_get_image_size())
1162                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1163         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1164
1165         for (i = 0; i < read_pages; i++) {
1166                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1167                                                   __GFP_WAIT | __GFP_HIGH :
1168                                                   __GFP_WAIT | __GFP_NOWARN |
1169                                                   __GFP_NORETRY);
1170
1171                 if (!page[i]) {
1172                         if (i < LZO_CMP_PAGES) {
1173                                 ring_size = i;
1174                                 printk(KERN_ERR
1175                                        "PM: Failed to allocate LZO pages\n");
1176                                 ret = -ENOMEM;
1177                                 goto out_clean;
1178                         } else {
1179                                 break;
1180                         }
1181                 }
1182         }
1183         want = ring_size = i;
1184
1185         printk(KERN_INFO
1186                 "PM: Using %u thread(s) for decompression.\n"
1187                 "PM: Loading and decompressing image data (%u pages)...\n",
1188                 nr_threads, nr_to_read);
1189         m = nr_to_read / 10;
1190         if (!m)
1191                 m = 1;
1192         nr_pages = 0;
1193         bio = NULL;
1194         start = ktime_get();
1195
1196         ret = snapshot_write_next(snapshot);
1197         if (ret <= 0)
1198                 goto out_finish;
1199
1200         for(;;) {
1201                 for (i = 0; !eof && i < want; i++) {
1202                         ret = swap_read_page(handle, page[ring], &bio);
1203                         if (ret) {
1204                                 /*
1205                                  * On real read error, finish. On end of data,
1206                                  * set EOF flag and just exit the read loop.
1207                                  */
1208                                 if (handle->cur &&
1209                                     handle->cur->entries[handle->k]) {
1210                                         goto out_finish;
1211                                 } else {
1212                                         eof = 1;
1213                                         break;
1214                                 }
1215                         }
1216                         if (++ring >= ring_size)
1217                                 ring = 0;
1218                 }
1219                 asked += i;
1220                 want -= i;
1221
1222                 /*
1223                  * We are out of data, wait for some more.
1224                  */
1225                 if (!have) {
1226                         if (!asked)
1227                                 break;
1228
1229                         ret = hib_wait_on_bio_chain(&bio);
1230                         if (ret)
1231                                 goto out_finish;
1232                         have += asked;
1233                         asked = 0;
1234                         if (eof)
1235                                 eof = 2;
1236                 }
1237
1238                 if (crc->run_threads) {
1239                         wait_event(crc->done, atomic_read(&crc->stop));
1240                         atomic_set(&crc->stop, 0);
1241                         crc->run_threads = 0;
1242                 }
1243
1244                 for (thr = 0; have && thr < nr_threads; thr++) {
1245                         data[thr].cmp_len = *(size_t *)page[pg];
1246                         if (unlikely(!data[thr].cmp_len ||
1247                                      data[thr].cmp_len >
1248                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1249                                 printk(KERN_ERR
1250                                        "PM: Invalid LZO compressed length\n");
1251                                 ret = -1;
1252                                 goto out_finish;
1253                         }
1254
1255                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1256                                             PAGE_SIZE);
1257                         if (need > have) {
1258                                 if (eof > 1) {
1259                                         ret = -1;
1260                                         goto out_finish;
1261                                 }
1262                                 break;
1263                         }
1264
1265                         for (off = 0;
1266                              off < LZO_HEADER + data[thr].cmp_len;
1267                              off += PAGE_SIZE) {
1268                                 memcpy(data[thr].cmp + off,
1269                                        page[pg], PAGE_SIZE);
1270                                 have--;
1271                                 want++;
1272                                 if (++pg >= ring_size)
1273                                         pg = 0;
1274                         }
1275
1276                         atomic_set(&data[thr].ready, 1);
1277                         wake_up(&data[thr].go);
1278                 }
1279
1280                 /*
1281                  * Wait for more data while we are decompressing.
1282                  */
1283                 if (have < LZO_CMP_PAGES && asked) {
1284                         ret = hib_wait_on_bio_chain(&bio);
1285                         if (ret)
1286                                 goto out_finish;
1287                         have += asked;
1288                         asked = 0;
1289                         if (eof)
1290                                 eof = 2;
1291                 }
1292
1293                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1294                         wait_event(data[thr].done,
1295                                    atomic_read(&data[thr].stop));
1296                         atomic_set(&data[thr].stop, 0);
1297
1298                         ret = data[thr].ret;
1299
1300                         if (ret < 0) {
1301                                 printk(KERN_ERR
1302                                        "PM: LZO decompression failed\n");
1303                                 goto out_finish;
1304                         }
1305
1306                         if (unlikely(!data[thr].unc_len ||
1307                                      data[thr].unc_len > LZO_UNC_SIZE ||
1308                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1309                                 printk(KERN_ERR
1310                                        "PM: Invalid LZO uncompressed length\n");
1311                                 ret = -1;
1312                                 goto out_finish;
1313                         }
1314
1315                         for (off = 0;
1316                              off < data[thr].unc_len; off += PAGE_SIZE) {
1317                                 memcpy(data_of(*snapshot),
1318                                        data[thr].unc + off, PAGE_SIZE);
1319
1320                                 if (!(nr_pages % m))
1321                                         printk(KERN_INFO
1322                                                "PM: Image loading progress: "
1323                                                "%3d%%\n",
1324                                                nr_pages / m * 10);
1325                                 nr_pages++;
1326
1327                                 ret = snapshot_write_next(snapshot);
1328                                 if (ret <= 0) {
1329                                         crc->run_threads = thr + 1;
1330                                         atomic_set(&crc->ready, 1);
1331                                         wake_up(&crc->go);
1332                                         goto out_finish;
1333                                 }
1334                         }
1335                 }
1336
1337                 crc->run_threads = thr;
1338                 atomic_set(&crc->ready, 1);
1339                 wake_up(&crc->go);
1340         }
1341
1342 out_finish:
1343         if (crc->run_threads) {
1344                 wait_event(crc->done, atomic_read(&crc->stop));
1345                 atomic_set(&crc->stop, 0);
1346         }
1347         stop = ktime_get();
1348         if (!ret) {
1349                 printk(KERN_INFO "PM: Image loading done.\n");
1350                 snapshot_write_finalize(snapshot);
1351                 if (!snapshot_image_loaded(snapshot))
1352                         ret = -ENODATA;
1353                 if (!ret) {
1354                         if (swsusp_header->flags & SF_CRC32_MODE) {
1355                                 if(handle->crc32 != swsusp_header->crc32) {
1356                                         printk(KERN_ERR
1357                                                "PM: Invalid image CRC32!\n");
1358                                         ret = -ENODATA;
1359                                 }
1360                         }
1361                 }
1362         }
1363         swsusp_show_speed(start, stop, nr_to_read, "Read");
1364 out_clean:
1365         for (i = 0; i < ring_size; i++)
1366                 free_page((unsigned long)page[i]);
1367         if (crc) {
1368                 if (crc->thr)
1369                         kthread_stop(crc->thr);
1370                 kfree(crc);
1371         }
1372         if (data) {
1373                 for (thr = 0; thr < nr_threads; thr++)
1374                         if (data[thr].thr)
1375                                 kthread_stop(data[thr].thr);
1376                 vfree(data);
1377         }
1378         vfree(page);
1379
1380         return ret;
1381 }
1382
1383 /**
1384  *      swsusp_read - read the hibernation image.
1385  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1386  *                be written into this memory location
1387  */
1388
1389 int swsusp_read(unsigned int *flags_p)
1390 {
1391         int error;
1392         struct swap_map_handle handle;
1393         struct snapshot_handle snapshot;
1394         struct swsusp_info *header;
1395
1396         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1397         error = snapshot_write_next(&snapshot);
1398         if (error < PAGE_SIZE)
1399                 return error < 0 ? error : -EFAULT;
1400         header = (struct swsusp_info *)data_of(snapshot);
1401         error = get_swap_reader(&handle, flags_p);
1402         if (error)
1403                 goto end;
1404         if (!error)
1405                 error = swap_read_page(&handle, header, NULL);
1406         if (!error) {
1407                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1408                         load_image(&handle, &snapshot, header->pages - 1) :
1409                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1410         }
1411         swap_reader_finish(&handle);
1412 end:
1413         if (!error)
1414                 pr_debug("PM: Image successfully loaded\n");
1415         else
1416                 pr_debug("PM: Error %d resuming\n", error);
1417         return error;
1418 }
1419
1420 /**
1421  *      swsusp_check - Check for swsusp signature in the resume device
1422  */
1423
1424 int swsusp_check(void)
1425 {
1426         int error;
1427
1428         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1429                                             FMODE_READ, NULL);
1430         if (!IS_ERR(hib_resume_bdev)) {
1431                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1432                 clear_page(swsusp_header);
1433                 error = hib_bio_read_page(swsusp_resume_block,
1434                                         swsusp_header, NULL);
1435                 if (error)
1436                         goto put;
1437
1438                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1439                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1440                         /* Reset swap signature now */
1441                         error = hib_bio_write_page(swsusp_resume_block,
1442                                                 swsusp_header, NULL);
1443                 } else {
1444                         error = -EINVAL;
1445                 }
1446
1447 put:
1448                 if (error)
1449                         blkdev_put(hib_resume_bdev, FMODE_READ);
1450                 else
1451                         pr_debug("PM: Image signature found, resuming\n");
1452         } else {
1453                 error = PTR_ERR(hib_resume_bdev);
1454         }
1455
1456         if (error)
1457                 pr_debug("PM: Image not found (code %d)\n", error);
1458
1459         return error;
1460 }
1461
1462 /**
1463  *      swsusp_close - close swap device.
1464  */
1465
1466 void swsusp_close(fmode_t mode)
1467 {
1468         if (IS_ERR(hib_resume_bdev)) {
1469                 pr_debug("PM: Image device not initialised\n");
1470                 return;
1471         }
1472
1473         blkdev_put(hib_resume_bdev, mode);
1474 }
1475
1476 /**
1477  *      swsusp_unmark - Unmark swsusp signature in the resume device
1478  */
1479
1480 #ifdef CONFIG_SUSPEND
1481 int swsusp_unmark(void)
1482 {
1483         int error;
1484
1485         hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
1486         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1487                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1488                 error = hib_bio_write_page(swsusp_resume_block,
1489                                         swsusp_header, NULL);
1490         } else {
1491                 printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
1492                 error = -ENODEV;
1493         }
1494
1495         /*
1496          * We just returned from suspend, we don't need the image any more.
1497          */
1498         free_all_swap_pages(root_swap);
1499
1500         return error;
1501 }
1502 #endif
1503
1504 static int swsusp_header_init(void)
1505 {
1506         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1507         if (!swsusp_header)
1508                 panic("Could not allocate memory for swsusp_header\n");
1509         return 0;
1510 }
1511
1512 core_initcall(swsusp_header_init);