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