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