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