kernel/power/swap.c

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