kernel/power/swap.c

   1 /*
   2  * linux/kernel/power/swap.c
   3  *
   4  * This file provides functions for reading the suspend image from
   5  * and writing it to a swap partition.
   6  *
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
   8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
   9  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
  10  *
  11  * This file is released under the GPLv2.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/file.h>
  17 #include <linux/delay.h>
  18 #include <linux/bitops.h>
  19 #include <linux/genhd.h>
  20 #include <linux/device.h>
  21 #include <linux/bio.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/swap.h>
  24 #include <linux/swapops.h>
  25 #include <linux/pm.h>
  26 #include <linux/slab.h>
  27 #include <linux/lzo.h>
  28 #include <linux/vmalloc.h>
  29 #include <linux/cpumask.h>
  30 #include <linux/atomic.h>
  31 #include <linux/kthread.h>
  32 #include <linux/crc32.h>
  33 #include <linux/ktime.h>
  34
  35 #include "power.h"
  36
  37 #define HIBERNATE_SIG   "S1SUSPEND"
  38
  39 /*
  40  *      The swap map is a data structure used for keeping track of each page
  41  *      written to a swap partition.  It consists of many swap_map_page
  42  *      structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
  43  *      These structures are stored on the swap and linked together with the
  44  *      help of the .next_swap member.
  45  *
  46  *      The swap map is created during suspend.  The swap map pages are
  47  *      allocated and populated one at a time, so we only need one memory
  48  *      page to set up the entire structure.
  49  *
  50  *      During resume we pick up all swap_map_page structures into a list.
  51  */
  52
  53 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
  54
  55 /*
  56  * Number of free pages that are not high.
  57  */
  58 static inline unsigned long low_free_pages(void)
  59 {
  60         return nr_free_pages() - nr_free_highpages();
  61 }
  62
  63 /*
  64  * Number of pages required to be kept free while writing the image. Always
  65  * half of all available low pages before the writing starts.
  66  */
  67 static inline unsigned long reqd_free_pages(void)
  68 {
  69         return low_free_pages() / 2;
  70 }
  71
  72 struct swap_map_page {
  73         sector_t entries[MAP_PAGE_ENTRIES];
  74         sector_t next_swap;
  75 };
  76
  77 struct swap_map_page_list {
  78         struct swap_map_page *map;
  79         struct swap_map_page_list *next;
  80 };
  81
  82 /**
  83  *      The swap_map_handle structure is used for handling swap in
  84  *      a file-alike way
  85  */
  86
  87 struct swap_map_handle {
  88         struct swap_map_page *cur;
  89         struct swap_map_page_list *maps;
  90         sector_t cur_swap;
  91         sector_t first_sector;
  92         unsigned int k;
  93         unsigned long reqd_free_pages;
  94         u32 crc32;
  95 };
  96
  97 struct swsusp_header {
  98         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
  99                       sizeof(u32)];
 100         u32     crc32;
 101         sector_t image;
 102         unsigned int flags;     /* Flags to pass to the "boot" kernel */
 103         char    orig_sig[10];
 104         char    sig[10];
 105 } __packed;
 106
 107 static struct swsusp_header *swsusp_header;
 108
 109 /**
 110  *      The following functions are used for tracing the allocated
 111  *      swap pages, so that they can be freed in case of an error.
 112  */
 113
 114 struct swsusp_extent {
 115         struct rb_node node;
 116         unsigned long start;
 117         unsigned long end;
 118 };
 119
 120 static struct rb_root swsusp_extents = RB_ROOT;
 121
 122 static int swsusp_extents_insert(unsigned long swap_offset)
 123 {
 124         struct rb_node **new = &(swsusp_extents.rb_node);
 125         struct rb_node *parent = NULL;
 126         struct swsusp_extent *ext;
 127
 128         /* Figure out where to put the new node */
 129         while (*new) {
 130                 ext = rb_entry(*new, struct swsusp_extent, node);
 131                 parent = *new;
 132                 if (swap_offset < ext->start) {
 133                         /* Try to merge */
 134                         if (swap_offset == ext->start - 1) {
 135                                 ext->start--;
 136                                 return 0;
 137                         }
 138                         new = &((*new)->rb_left);
 139                 } else if (swap_offset > ext->end) {
 140                         /* Try to merge */
 141                         if (swap_offset == ext->end + 1) {
 142                                 ext->end++;
 143                                 return 0;
 144                         }
 145                         new = &((*new)->rb_right);
 146                 } else {
 147                         /* It already is in the tree */
 148                         return -EINVAL;
 149                 }
 150         }
 151         /* Add the new node and rebalance the tree. */
 152         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
 153         if (!ext)
 154                 return -ENOMEM;
 155
 156         ext->start = swap_offset;
 157         ext->end = swap_offset;
 158         rb_link_node(&ext->node, parent, new);
 159         rb_insert_color(&ext->node, &swsusp_extents);
 160         return 0;
 161 }
 162
 163 /**
 164  *      alloc_swapdev_block - allocate a swap page and register that it has
 165  *      been allocated, so that it can be freed in case of an error.
 166  */
 167
 168 sector_t alloc_swapdev_block(int swap)
 169 {
 170         unsigned long offset;
 171
 172         offset = swp_offset(get_swap_page_of_type(swap));
 173         if (offset) {
 174                 if (swsusp_extents_insert(offset))
 175                         swap_free(swp_entry(swap, offset));
 176                 else
 177                         return swapdev_block(swap, offset);
 178         }
 179         return 0;
 180 }
 181
 182 /**
 183  *      free_all_swap_pages - free swap pages allocated for saving image data.
 184  *      It also frees the extents used to register which swap entries had been
 185  *      allocated.
 186  */
 187
 188 void free_all_swap_pages(int swap)
 189 {
 190         struct rb_node *node;
 191
 192         while ((node = swsusp_extents.rb_node)) {
 193                 struct swsusp_extent *ext;
 194                 unsigned long offset;
 195
 196                 ext = container_of(node, struct swsusp_extent, node);
 197                 rb_erase(node, &swsusp_extents);
 198                 for (offset = ext->start; offset <= ext->end; offset++)
 199                         swap_free(swp_entry(swap, offset));
 200
 201                 kfree(ext);
 202         }
 203 }
 204
 205 int swsusp_swap_in_use(void)
 206 {
 207         return (swsusp_extents.rb_node != NULL);
 208 }
 209
 210 /*
 211  * General things
 212  */
 213
 214 static unsigned short root_swap = 0xffff;
 215 static struct block_device *hib_resume_bdev;
 216
 217 struct hib_bio_batch {
 218         atomic_t                count;
 219         wait_queue_head_t       wait;
 220         int                     error;
 221 };
 222
 223 static void hib_init_batch(struct hib_bio_batch *hb)
 224 {
 225         atomic_set(&hb->count, 0);
 226         init_waitqueue_head(&hb->wait);
 227         hb->error = 0;
 228 }
 229
 230 static void hib_end_io(struct bio *bio, int error)
 231 {
 232         struct hib_bio_batch *hb = bio->bi_private;
 233         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 234         struct page *page = bio->bi_io_vec[0].bv_page;
 235
 236         if (!uptodate || error) {
 237                 printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
 238                                 imajor(bio->bi_bdev->bd_inode),
 239                                 iminor(bio->bi_bdev->bd_inode),
 240                                 (unsigned long long)bio->bi_iter.bi_sector);
 241
 242                 if (!error)
 243                         error = -EIO;
 244         }
 245
 246         if (bio_data_dir(bio) == WRITE)
 247                 put_page(page);
 248
 249         if (error && !hb->error)
 250                 hb->error = error;
 251         if (atomic_dec_and_test(&hb->count))
 252                 wake_up(&hb->wait);
 253
 254         bio_put(bio);
 255 }
 256
 257 static int hib_submit_io(int rw, pgoff_t page_off, void *addr,
 258                 struct hib_bio_batch *hb)
 259 {
 260         struct page *page = virt_to_page(addr);
 261         struct bio *bio;
 262         int error = 0;
 263
 264         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
 265         bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
 266         bio->bi_bdev = hib_resume_bdev;
 267
 268         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
 269                 printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
 270                         (unsigned long long)bio->bi_iter.bi_sector);
 271                 bio_put(bio);
 272                 return -EFAULT;
 273         }
 274
 275         if (hb) {
 276                 bio->bi_end_io = hib_end_io;
 277                 bio->bi_private = hb;
 278                 atomic_inc(&hb->count);
 279                 submit_bio(rw, bio);
 280         } else {
 281                 error = submit_bio_wait(rw, bio);
 282                 bio_put(bio);
 283         }
 284
 285         return error;
 286 }
 287
 288 static int hib_wait_io(struct hib_bio_batch *hb)
 289 {
 290         wait_event(hb->wait, atomic_read(&hb->count) == 0);
 291         return hb->error;
 292 }
 293
 294 /*
 295  * Saving part
 296  */
 297
 298 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 299 {
 300         int error;
 301
 302         hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
 303         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 304             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 305                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 306                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
 307                 swsusp_header->image = handle->first_sector;
 308                 swsusp_header->flags = flags;
 309                 if (flags & SF_CRC32_MODE)
 310                         swsusp_header->crc32 = handle->crc32;
 311                 error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
 312                                         swsusp_header, NULL);
 313         } else {
 314                 printk(KERN_ERR "PM: Swap header not found!\n");
 315                 error = -ENODEV;
 316         }
 317         return error;
 318 }
 319
 320 /**
 321  *      swsusp_swap_check - check if the resume device is a swap device
 322  *      and get its index (if so)
 323  *
 324  *      This is called before saving image
 325  */
 326 static int swsusp_swap_check(void)
 327 {
 328         int res;
 329
 330         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 331                         &hib_resume_bdev);
 332         if (res < 0)
 333                 return res;
 334
 335         root_swap = res;
 336         res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
 337         if (res)
 338                 return res;
 339
 340         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
 341         if (res < 0)
 342                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
 343
 344         return res;
 345 }
 346
 347 /**
 348  *      write_page - Write one page to given swap location.
 349  *      @buf:           Address we're writing.
 350  *      @offset:        Offset of the swap page we're writing to.
 351  *      @hb:            bio completion batch
 352  */
 353
 354 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 355 {
 356         void *src;
 357         int ret;
 358
 359         if (!offset)
 360                 return -ENOSPC;
 361
 362         if (hb) {
 363                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
 364                                               __GFP_NORETRY);
 365                 if (src) {
 366                         copy_page(src, buf);
 367                 } else {
 368                         ret = hib_wait_io(hb); /* Free pages */
 369                         if (ret)
 370                                 return ret;
 371                         src = (void *)__get_free_page(__GFP_WAIT |
 372                                                       __GFP_NOWARN |
 373                                                       __GFP_NORETRY);
 374                         if (src) {
 375                                 copy_page(src, buf);
 376                         } else {
 377                                 WARN_ON_ONCE(1);
 378                                 hb = NULL;      /* Go synchronous */
 379                                 src = buf;
 380                         }
 381                 }
 382         } else {
 383                 src = buf;
 384         }
 385         return hib_submit_io(WRITE_SYNC, offset, src, hb);
 386 }
 387
 388 static void release_swap_writer(struct swap_map_handle *handle)
 389 {
 390         if (handle->cur)
 391                 free_page((unsigned long)handle->cur);
 392         handle->cur = NULL;
 393 }
 394
 395 static int get_swap_writer(struct swap_map_handle *handle)
 396 {
 397         int ret;
 398
 399         ret = swsusp_swap_check();
 400         if (ret) {
 401                 if (ret != -ENOSPC)
 402                         printk(KERN_ERR "PM: Cannot find swap device, try "
 403                                         "swapon -a.\n");
 404                 return ret;
 405         }
 406         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 407         if (!handle->cur) {
 408                 ret = -ENOMEM;
 409                 goto err_close;
 410         }
 411         handle->cur_swap = alloc_swapdev_block(root_swap);
 412         if (!handle->cur_swap) {
 413                 ret = -ENOSPC;
 414                 goto err_rel;
 415         }
 416         handle->k = 0;
 417         handle->reqd_free_pages = reqd_free_pages();
 418         handle->first_sector = handle->cur_swap;
 419         return 0;
 420 err_rel:
 421         release_swap_writer(handle);
 422 err_close:
 423         swsusp_close(FMODE_WRITE);
 424         return ret;
 425 }
 426
 427 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 428                 struct hib_bio_batch *hb)
 429 {
 430         int error = 0;
 431         sector_t offset;
 432
 433         if (!handle->cur)
 434                 return -EINVAL;
 435         offset = alloc_swapdev_block(root_swap);
 436         error = write_page(buf, offset, hb);
 437         if (error)
 438                 return error;
 439         handle->cur->entries[handle->k++] = offset;
 440         if (handle->k >= MAP_PAGE_ENTRIES) {
 441                 offset = alloc_swapdev_block(root_swap);
 442                 if (!offset)
 443                         return -ENOSPC;
 444                 handle->cur->next_swap = offset;
 445                 error = write_page(handle->cur, handle->cur_swap, hb);
 446                 if (error)
 447                         goto out;
 448                 clear_page(handle->cur);
 449                 handle->cur_swap = offset;
 450                 handle->k = 0;
 451
 452                 if (hb && low_free_pages() <= handle->reqd_free_pages) {
 453                         error = hib_wait_io(hb);
 454                         if (error)
 455                                 goto out;
 456                         /*
 457                          * Recalculate the number of required free pages, to
 458                          * make sure we never take more than half.
 459                          */
 460                         handle->reqd_free_pages = reqd_free_pages();
 461                 }
 462         }
 463  out:
 464         return error;
 465 }
 466
 467 static int flush_swap_writer(struct swap_map_handle *handle)
 468 {
 469         if (handle->cur && handle->cur_swap)
 470                 return write_page(handle->cur, handle->cur_swap, NULL);
 471         else
 472                 return -EINVAL;
 473 }
 474
 475 static int swap_writer_finish(struct swap_map_handle *handle,
 476                 unsigned int flags, int error)
 477 {
 478         if (!error) {
 479                 flush_swap_writer(handle);
 480                 printk(KERN_INFO "PM: S");
 481                 error = mark_swapfiles(handle, flags);
 482                 printk("|\n");
 483         }
 484
 485         if (error)
 486                 free_all_swap_pages(root_swap);
 487         release_swap_writer(handle);
 488         swsusp_close(FMODE_WRITE);
 489
 490         return error;
 491 }
 492
 493 /* We need to remember how much compressed data we need to read. */
 494 #define LZO_HEADER      sizeof(size_t)
 495
 496 /* Number of pages/bytes we'll compress at one time. */
 497 #define LZO_UNC_PAGES   32
 498 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
 499
 500 /* Number of pages/bytes we need for compressed data (worst case). */
 501 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
 502                                      LZO_HEADER, PAGE_SIZE)
 503 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
 504
 505 /* Maximum number of threads for compression/decompression. */
 506 #define LZO_THREADS     3
 507
 508 /* Minimum/maximum number of pages for read buffering. */
 509 #define LZO_MIN_RD_PAGES        1024
 510 #define LZO_MAX_RD_PAGES        8192
 511
 512
 513 /**
 514  *      save_image - save the suspend image data
 515  */
 516
 517 static int save_image(struct swap_map_handle *handle,
 518                       struct snapshot_handle *snapshot,
 519                       unsigned int nr_to_write)
 520 {
 521         unsigned int m;
 522         int ret;
 523         int nr_pages;
 524         int err2;
 525         struct hib_bio_batch hb;
 526         ktime_t start;
 527         ktime_t stop;
 528
 529         hib_init_batch(&hb);
 530
 531         printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
 532                 nr_to_write);
 533         m = nr_to_write / 10;
 534         if (!m)
 535                 m = 1;
 536         nr_pages = 0;
 537         start = ktime_get();
 538         while (1) {
 539                 ret = snapshot_read_next(snapshot);
 540                 if (ret <= 0)
 541                         break;
 542                 ret = swap_write_page(handle, data_of(*snapshot), &hb);
 543                 if (ret)
 544                         break;
 545                 if (!(nr_pages % m))
 546                         printk(KERN_INFO "PM: Image saving progress: %3d%%\n",
 547                                nr_pages / m * 10);
 548                 nr_pages++;
 549         }
 550         err2 = hib_wait_io(&hb);
 551         stop = ktime_get();
 552         if (!ret)
 553                 ret = err2;
 554         if (!ret)
 555                 printk(KERN_INFO "PM: Image saving done.\n");
 556         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 557         return ret;
 558 }
 559
 560 /**
 561  * Structure used for CRC32.
 562  */
 563 struct crc_data {
 564         struct task_struct *thr;                  /* thread */
 565         atomic_t ready;                           /* ready to start flag */
 566         atomic_t stop;                            /* ready to stop flag */
 567         unsigned run_threads;                     /* nr current threads */
 568         wait_queue_head_t go;                     /* start crc update */
 569         wait_queue_head_t done;                   /* crc update done */
 570         u32 *crc32;                               /* points to handle's crc32 */
 571         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
 572         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
 573 };
 574
 575 /**
 576  * CRC32 update function that runs in its own thread.
 577  */
 578 static int crc32_threadfn(void *data)
 579 {
 580         struct crc_data *d = data;
 581         unsigned i;
 582
 583         while (1) {
 584                 wait_event(d->go, atomic_read(&d->ready) ||
 585                                   kthread_should_stop());
 586                 if (kthread_should_stop()) {
 587                         d->thr = NULL;
 588                         atomic_set(&d->stop, 1);
 589                         wake_up(&d->done);
 590                         break;
 591                 }
 592                 atomic_set(&d->ready, 0);
 593
 594                 for (i = 0; i < d->run_threads; i++)
 595                         *d->crc32 = crc32_le(*d->crc32,
 596                                              d->unc[i], *d->unc_len[i]);
 597                 atomic_set(&d->stop, 1);
 598                 wake_up(&d->done);
 599         }
 600         return 0;
 601 }
 602 /**
 603  * Structure used for LZO data compression.
 604  */
 605 struct cmp_data {
 606         struct task_struct *thr;                  /* thread */
 607         atomic_t ready;                           /* ready to start flag */
 608         atomic_t stop;                            /* ready to stop flag */
 609         int ret;                                  /* return code */
 610         wait_queue_head_t go;                     /* start compression */
 611         wait_queue_head_t done;                   /* compression done */
 612         size_t unc_len;                           /* uncompressed length */
 613         size_t cmp_len;                           /* compressed length */
 614         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
 615         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
 616         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
 617 };
 618
 619 /**
 620  * Compression function that runs in its own thread.
 621  */
 622 static int lzo_compress_threadfn(void *data)
 623 {
 624         struct cmp_data *d = data;
 625
 626         while (1) {
 627                 wait_event(d->go, atomic_read(&d->ready) ||
 628                                   kthread_should_stop());
 629                 if (kthread_should_stop()) {
 630                         d->thr = NULL;
 631                         d->ret = -1;
 632                         atomic_set(&d->stop, 1);
 633                         wake_up(&d->done);
 634                         break;
 635                 }
 636                 atomic_set(&d->ready, 0);
 637
 638                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
 639                                           d->cmp + LZO_HEADER, &d->cmp_len,
 640                                           d->wrk);
 641                 atomic_set(&d->stop, 1);
 642                 wake_up(&d->done);
 643         }
 644         return 0;
 645 }
 646
 647 /**
 648  * save_image_lzo - Save the suspend image data compressed with LZO.
 649  * @handle: Swap map handle to use for saving the image.
 650  * @snapshot: Image to read data from.
 651  * @nr_to_write: Number of pages to save.
 652  */
 653 static int save_image_lzo(struct swap_map_handle *handle,
 654                           struct snapshot_handle *snapshot,
 655                           unsigned int nr_to_write)
 656 {
 657         unsigned int m;
 658         int ret = 0;
 659         int nr_pages;
 660         int err2;
 661         struct hib_bio_batch hb;
 662         ktime_t start;
 663         ktime_t stop;
 664         size_t off;
 665         unsigned thr, run_threads, nr_threads;
 666         unsigned char *page = NULL;
 667         struct cmp_data *data = NULL;
 668         struct crc_data *crc = NULL;
 669
 670         hib_init_batch(&hb);
 671
 672         /*
 673          * We'll limit the number of threads for compression to limit memory
 674          * footprint.
 675          */
 676         nr_threads = num_online_cpus() - 1;
 677         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 678
 679         page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 680         if (!page) {
 681                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
 682                 ret = -ENOMEM;
 683                 goto out_clean;
 684         }
 685
 686         data = vmalloc(sizeof(*data) * nr_threads);
 687         if (!data) {
 688                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
 689                 ret = -ENOMEM;
 690                 goto out_clean;
 691         }
 692         for (thr = 0; thr < nr_threads; thr++)
 693                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
 694
 695         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
 696         if (!crc) {
 697                 printk(KERN_ERR "PM: Failed to allocate crc\n");
 698                 ret = -ENOMEM;
 699                 goto out_clean;
 700         }
 701         memset(crc, 0, offsetof(struct crc_data, go));
 702
 703         /*
 704          * Start the compression threads.
 705          */
 706         for (thr = 0; thr < nr_threads; thr++) {
 707                 init_waitqueue_head(&data[thr].go);
 708                 init_waitqueue_head(&data[thr].done);
 709
 710                 data[thr].thr = kthread_run(lzo_compress_threadfn,
 711                                             &data[thr],
 712                                             "image_compress/%u", thr);
 713                 if (IS_ERR(data[thr].thr)) {
 714                         data[thr].thr = NULL;
 715                         printk(KERN_ERR
 716                                "PM: Cannot start compression threads\n");
 717                         ret = -ENOMEM;
 718                         goto out_clean;
 719                 }
 720         }
 721
 722         /*
 723          * Start the CRC32 thread.
 724          */
 725         init_waitqueue_head(&crc->go);
 726         init_waitqueue_head(&crc->done);
 727
 728         handle->crc32 = 0;
 729         crc->crc32 = &handle->crc32;
 730         for (thr = 0; thr < nr_threads; thr++) {
 731                 crc->unc[thr] = data[thr].unc;
 732                 crc->unc_len[thr] = &data[thr].unc_len;
 733         }
 734
 735         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
 736         if (IS_ERR(crc->thr)) {
 737                 crc->thr = NULL;
 738                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
 739                 ret = -ENOMEM;
 740                 goto out_clean;
 741         }
 742
 743         /*
 744          * Adjust the number of required free pages after all allocations have
 745          * been done. We don't want to run out of pages when writing.
 746          */
 747         handle->reqd_free_pages = reqd_free_pages();
 748
 749         printk(KERN_INFO
 750                 "PM: Using %u thread(s) for compression.\n"
 751                 "PM: Compressing and saving image data (%u pages)...\n",
 752                 nr_threads, nr_to_write);
 753         m = nr_to_write / 10;
 754         if (!m)
 755                 m = 1;
 756         nr_pages = 0;
 757         start = ktime_get();
 758         for (;;) {
 759                 for (thr = 0; thr < nr_threads; thr++) {
 760                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
 761                                 ret = snapshot_read_next(snapshot);
 762                                 if (ret < 0)
 763                                         goto out_finish;
 764
 765                                 if (!ret)
 766                                         break;
 767
 768                                 memcpy(data[thr].unc + off,
 769                                        data_of(*snapshot), PAGE_SIZE);
 770
 771                                 if (!(nr_pages % m))
 772                                         printk(KERN_INFO
 773                                                "PM: Image saving progress: "
 774                                                "%3d%%\n",
 775                                                nr_pages / m * 10);
 776                                 nr_pages++;
 777                         }
 778                         if (!off)
 779                                 break;
 780
 781                         data[thr].unc_len = off;
 782
 783                         atomic_set(&data[thr].ready, 1);
 784                         wake_up(&data[thr].go);
 785                 }
 786
 787                 if (!thr)
 788                         break;
 789
 790                 crc->run_threads = thr;
 791                 atomic_set(&crc->ready, 1);
 792                 wake_up(&crc->go);
 793
 794                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
 795                         wait_event(data[thr].done,
 796                                    atomic_read(&data[thr].stop));
 797                         atomic_set(&data[thr].stop, 0);
 798
 799                         ret = data[thr].ret;
 800
 801                         if (ret < 0) {
 802                                 printk(KERN_ERR "PM: LZO compression failed\n");
 803                                 goto out_finish;
 804                         }
 805
 806                         if (unlikely(!data[thr].cmp_len ||
 807                                      data[thr].cmp_len >
 808                                      lzo1x_worst_compress(data[thr].unc_len))) {
 809                                 printk(KERN_ERR
 810                                        "PM: Invalid LZO compressed length\n");
 811                                 ret = -1;
 812                                 goto out_finish;
 813                         }
 814
 815                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
 816
 817                         /*
 818                          * Given we are writing one page at a time to disk, we
 819                          * copy that much from the buffer, although the last
 820                          * bit will likely be smaller than full page. This is
 821                          * OK - we saved the length of the compressed data, so
 822                          * any garbage at the end will be discarded when we
 823                          * read it.
 824                          */
 825                         for (off = 0;
 826                              off < LZO_HEADER + data[thr].cmp_len;
 827                              off += PAGE_SIZE) {
 828                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
 829
 830                                 ret = swap_write_page(handle, page, &hb);
 831                                 if (ret)
 832                                         goto out_finish;
 833                         }
 834                 }
 835
 836                 wait_event(crc->done, atomic_read(&crc->stop));
 837                 atomic_set(&crc->stop, 0);
 838         }
 839
 840 out_finish:
 841         err2 = hib_wait_io(&hb);
 842         stop = ktime_get();
 843         if (!ret)
 844                 ret = err2;
 845         if (!ret)
 846                 printk(KERN_INFO "PM: Image saving done.\n");
 847         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 848 out_clean:
 849         if (crc) {
 850                 if (crc->thr)
 851                         kthread_stop(crc->thr);
 852                 kfree(crc);
 853         }
 854         if (data) {
 855                 for (thr = 0; thr < nr_threads; thr++)
 856                         if (data[thr].thr)
 857                                 kthread_stop(data[thr].thr);
 858                 vfree(data);
 859         }
 860         if (page) free_page((unsigned long)page);
 861
 862         return ret;
 863 }
 864
 865 /**
 866  *      enough_swap - Make sure we have enough swap to save the image.
 867  *
 868  *      Returns TRUE or FALSE after checking the total amount of swap
 869  *      space avaiable from the resume partition.
 870  */
 871
 872 static int enough_swap(unsigned int nr_pages, unsigned int flags)
 873 {
 874         unsigned int free_swap = count_swap_pages(root_swap, 1);
 875         unsigned int required;
 876
 877         pr_debug("PM: Free swap pages: %u\n", free_swap);
 878
 879         required = PAGES_FOR_IO + nr_pages;
 880         return free_swap > required;
 881 }
 882
 883 /**
 884  *      swsusp_write - Write entire image and metadata.
 885  *      @flags: flags to pass to the "boot" kernel in the image header
 886  *
 887  *      It is important _NOT_ to umount filesystems at this point. We want
 888  *      them synced (in case something goes wrong) but we DO not want to mark
 889  *      filesystem clean: it is not. (And it does not matter, if we resume
 890  *      correctly, we'll mark system clean, anyway.)
 891  */
 892
 893 int swsusp_write(unsigned int flags)
 894 {
 895         struct swap_map_handle handle;
 896         struct snapshot_handle snapshot;
 897         struct swsusp_info *header;
 898         unsigned long pages;
 899         int error;
 900
 901         pages = snapshot_get_image_size();
 902         error = get_swap_writer(&handle);
 903         if (error) {
 904                 printk(KERN_ERR "PM: Cannot get swap writer\n");
 905                 return error;
 906         }
 907         if (flags & SF_NOCOMPRESS_MODE) {
 908                 if (!enough_swap(pages, flags)) {
 909                         printk(KERN_ERR "PM: Not enough free swap\n");
 910                         error = -ENOSPC;
 911                         goto out_finish;
 912                 }
 913         }
 914         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 915         error = snapshot_read_next(&snapshot);
 916         if (error < PAGE_SIZE) {
 917                 if (error >= 0)
 918                         error = -EFAULT;
 919
 920                 goto out_finish;
 921         }
 922         header = (struct swsusp_info *)data_of(snapshot);
 923         error = swap_write_page(&handle, header, NULL);
 924         if (!error) {
 925                 error = (flags & SF_NOCOMPRESS_MODE) ?
 926                         save_image(&handle, &snapshot, pages - 1) :
 927                         save_image_lzo(&handle, &snapshot, pages - 1);
 928         }
 929 out_finish:
 930         error = swap_writer_finish(&handle, flags, error);
 931         return error;
 932 }
 933
 934 /**
 935  *      The following functions allow us to read data using a swap map
 936  *      in a file-alike way
 937  */
 938
 939 static void release_swap_reader(struct swap_map_handle *handle)
 940 {
 941         struct swap_map_page_list *tmp;
 942
 943         while (handle->maps) {
 944                 if (handle->maps->map)
 945                         free_page((unsigned long)handle->maps->map);
 946                 tmp = handle->maps;
 947                 handle->maps = handle->maps->next;
 948                 kfree(tmp);
 949         }
 950         handle->cur = NULL;
 951 }
 952
 953 static int get_swap_reader(struct swap_map_handle *handle,
 954                 unsigned int *flags_p)
 955 {
 956         int error;
 957         struct swap_map_page_list *tmp, *last;
 958         sector_t offset;
 959
 960         *flags_p = swsusp_header->flags;
 961
 962         if (!swsusp_header->image) /* how can this happen? */
 963                 return -EINVAL;
 964
 965         handle->cur = NULL;
 966         last = handle->maps = NULL;
 967         offset = swsusp_header->image;
 968         while (offset) {
 969                 tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
 970                 if (!tmp) {
 971                         release_swap_reader(handle);
 972                         return -ENOMEM;
 973                 }
 974                 memset(tmp, 0, sizeof(*tmp));
 975                 if (!handle->maps)
 976                         handle->maps = tmp;
 977                 if (last)
 978                         last->next = tmp;
 979                 last = tmp;
 980
 981                 tmp->map = (struct swap_map_page *)
 982                            __get_free_page(__GFP_WAIT | __GFP_HIGH);
 983                 if (!tmp->map) {
 984                         release_swap_reader(handle);
 985                         return -ENOMEM;
 986                 }
 987
 988                 error = hib_submit_io(READ_SYNC, offset, tmp->map, NULL);
 989                 if (error) {
 990                         release_swap_reader(handle);
 991                         return error;
 992                 }
 993                 offset = tmp->map->next_swap;
 994         }
 995         handle->k = 0;
 996         handle->cur = handle->maps->map;
 997         return 0;
 998 }
 999
1000 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1001                 struct hib_bio_batch *hb)
1002 {
1003         sector_t offset;
1004         int error;
1005         struct swap_map_page_list *tmp;
1006
1007         if (!handle->cur)
1008                 return -EINVAL;
1009         offset = handle->cur->entries[handle->k];
1010         if (!offset)
1011                 return -EFAULT;
1012         error = hib_submit_io(READ_SYNC, offset, buf, hb);
1013         if (error)
1014                 return error;
1015         if (++handle->k >= MAP_PAGE_ENTRIES) {
1016                 handle->k = 0;
1017                 free_page((unsigned long)handle->maps->map);
1018                 tmp = handle->maps;
1019                 handle->maps = handle->maps->next;
1020                 kfree(tmp);
1021                 if (!handle->maps)
1022                         release_swap_reader(handle);
1023                 else
1024                         handle->cur = handle->maps->map;
1025         }
1026         return error;
1027 }
1028
1029 static int swap_reader_finish(struct swap_map_handle *handle)
1030 {
1031         release_swap_reader(handle);
1032
1033         return 0;
1034 }
1035
1036 /**
1037  *      load_image - load the image using the swap map handle
1038  *      @handle and the snapshot handle @snapshot
1039  *      (assume there are @nr_pages pages to load)
1040  */
1041
1042 static int load_image(struct swap_map_handle *handle,
1043                       struct snapshot_handle *snapshot,
1044                       unsigned int nr_to_read)
1045 {
1046         unsigned int m;
1047         int ret = 0;
1048         ktime_t start;
1049         ktime_t stop;
1050         struct hib_bio_batch hb;
1051         int err2;
1052         unsigned nr_pages;
1053
1054         hib_init_batch(&hb);
1055
1056         printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
1057                 nr_to_read);
1058         m = nr_to_read / 10;
1059         if (!m)
1060                 m = 1;
1061         nr_pages = 0;
1062         start = ktime_get();
1063         for ( ; ; ) {
1064                 ret = snapshot_write_next(snapshot);
1065                 if (ret <= 0)
1066                         break;
1067                 ret = swap_read_page(handle, data_of(*snapshot), &hb);
1068                 if (ret)
1069                         break;
1070                 if (snapshot->sync_read)
1071                         ret = hib_wait_io(&hb);
1072                 if (ret)
1073                         break;
1074                 if (!(nr_pages % m))
1075                         printk(KERN_INFO "PM: Image loading progress: %3d%%\n",
1076                                nr_pages / m * 10);
1077                 nr_pages++;
1078         }
1079         err2 = hib_wait_io(&hb);
1080         stop = ktime_get();
1081         if (!ret)
1082                 ret = err2;
1083         if (!ret) {
1084                 printk(KERN_INFO "PM: Image loading done.\n");
1085                 snapshot_write_finalize(snapshot);
1086                 if (!snapshot_image_loaded(snapshot))
1087                         ret = -ENODATA;
1088         }
1089         swsusp_show_speed(start, stop, nr_to_read, "Read");
1090         return ret;
1091 }
1092
1093 /**
1094  * Structure used for LZO data decompression.
1095  */
1096 struct dec_data {
1097         struct task_struct *thr;                  /* thread */
1098         atomic_t ready;                           /* ready to start flag */
1099         atomic_t stop;                            /* ready to stop flag */
1100         int ret;                                  /* return code */
1101         wait_queue_head_t go;                     /* start decompression */
1102         wait_queue_head_t done;                   /* decompression done */
1103         size_t unc_len;                           /* uncompressed length */
1104         size_t cmp_len;                           /* compressed length */
1105         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1106         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1107 };
1108
1109 /**
1110  * Deompression function that runs in its own thread.
1111  */
1112 static int lzo_decompress_threadfn(void *data)
1113 {
1114         struct dec_data *d = data;
1115
1116         while (1) {
1117                 wait_event(d->go, atomic_read(&d->ready) ||
1118                                   kthread_should_stop());
1119                 if (kthread_should_stop()) {
1120                         d->thr = NULL;
1121                         d->ret = -1;
1122                         atomic_set(&d->stop, 1);
1123                         wake_up(&d->done);
1124                         break;
1125                 }
1126                 atomic_set(&d->ready, 0);
1127
1128                 d->unc_len = LZO_UNC_SIZE;
1129                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1130                                                d->unc, &d->unc_len);
1131                 atomic_set(&d->stop, 1);
1132                 wake_up(&d->done);
1133         }
1134         return 0;
1135 }
1136
1137 /**
1138  * load_image_lzo - Load compressed image data and decompress them with LZO.
1139  * @handle: Swap map handle to use for loading data.
1140  * @snapshot: Image to copy uncompressed data into.
1141  * @nr_to_read: Number of pages to load.
1142  */
1143 static int load_image_lzo(struct swap_map_handle *handle,
1144                           struct snapshot_handle *snapshot,
1145                           unsigned int nr_to_read)
1146 {
1147         unsigned int m;
1148         int ret = 0;
1149         int eof = 0;
1150         struct hib_bio_batch hb;
1151         ktime_t start;
1152         ktime_t stop;
1153         unsigned nr_pages;
1154         size_t off;
1155         unsigned i, thr, run_threads, nr_threads;
1156         unsigned ring = 0, pg = 0, ring_size = 0,
1157                  have = 0, want, need, asked = 0;
1158         unsigned long read_pages = 0;
1159         unsigned char **page = NULL;
1160         struct dec_data *data = NULL;
1161         struct crc_data *crc = NULL;
1162
1163         hib_init_batch(&hb);
1164
1165         /*
1166          * We'll limit the number of threads for decompression to limit memory
1167          * footprint.
1168          */
1169         nr_threads = num_online_cpus() - 1;
1170         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1171
1172         page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
1173         if (!page) {
1174                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
1175                 ret = -ENOMEM;
1176                 goto out_clean;
1177         }
1178
1179         data = vmalloc(sizeof(*data) * nr_threads);
1180         if (!data) {
1181                 printk(KERN_ERR "PM: Failed to allocate LZO data\n");
1182                 ret = -ENOMEM;
1183                 goto out_clean;
1184         }
1185         for (thr = 0; thr < nr_threads; thr++)
1186                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1187
1188         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1189         if (!crc) {
1190                 printk(KERN_ERR "PM: Failed to allocate crc\n");
1191                 ret = -ENOMEM;
1192                 goto out_clean;
1193         }
1194         memset(crc, 0, offsetof(struct crc_data, go));
1195
1196         /*
1197          * Start the decompression threads.
1198          */
1199         for (thr = 0; thr < nr_threads; thr++) {
1200                 init_waitqueue_head(&data[thr].go);
1201                 init_waitqueue_head(&data[thr].done);
1202
1203                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1204                                             &data[thr],
1205                                             "image_decompress/%u", thr);
1206                 if (IS_ERR(data[thr].thr)) {
1207                         data[thr].thr = NULL;
1208                         printk(KERN_ERR
1209                                "PM: Cannot start decompression threads\n");
1210                         ret = -ENOMEM;
1211                         goto out_clean;
1212                 }
1213         }
1214
1215         /*
1216          * Start the CRC32 thread.
1217          */
1218         init_waitqueue_head(&crc->go);
1219         init_waitqueue_head(&crc->done);
1220
1221         handle->crc32 = 0;
1222         crc->crc32 = &handle->crc32;
1223         for (thr = 0; thr < nr_threads; thr++) {
1224                 crc->unc[thr] = data[thr].unc;
1225                 crc->unc_len[thr] = &data[thr].unc_len;
1226         }
1227
1228         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1229         if (IS_ERR(crc->thr)) {
1230                 crc->thr = NULL;
1231                 printk(KERN_ERR "PM: Cannot start CRC32 thread\n");
1232                 ret = -ENOMEM;
1233                 goto out_clean;
1234         }
1235
1236         /*
1237          * Set the number of pages for read buffering.
1238          * This is complete guesswork, because we'll only know the real
1239          * picture once prepare_image() is called, which is much later on
1240          * during the image load phase. We'll assume the worst case and
1241          * say that none of the image pages are from high memory.
1242          */
1243         if (low_free_pages() > snapshot_get_image_size())
1244                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1245         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1246
1247         for (i = 0; i < read_pages; i++) {
1248                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1249                                                   __GFP_WAIT | __GFP_HIGH :
1250                                                   __GFP_WAIT | __GFP_NOWARN |
1251                                                   __GFP_NORETRY);
1252
1253                 if (!page[i]) {
1254                         if (i < LZO_CMP_PAGES) {
1255                                 ring_size = i;
1256                                 printk(KERN_ERR
1257                                        "PM: Failed to allocate LZO pages\n");
1258                                 ret = -ENOMEM;
1259                                 goto out_clean;
1260                         } else {
1261                                 break;
1262                         }
1263                 }
1264         }
1265         want = ring_size = i;
1266
1267         printk(KERN_INFO
1268                 "PM: Using %u thread(s) for decompression.\n"
1269                 "PM: Loading and decompressing image data (%u pages)...\n",
1270                 nr_threads, nr_to_read);
1271         m = nr_to_read / 10;
1272         if (!m)
1273                 m = 1;
1274         nr_pages = 0;
1275         start = ktime_get();
1276
1277         ret = snapshot_write_next(snapshot);
1278         if (ret <= 0)
1279                 goto out_finish;
1280
1281         for(;;) {
1282                 for (i = 0; !eof && i < want; i++) {
1283                         ret = swap_read_page(handle, page[ring], &hb);
1284                         if (ret) {
1285                                 /*
1286                                  * On real read error, finish. On end of data,
1287                                  * set EOF flag and just exit the read loop.
1288                                  */
1289                                 if (handle->cur &&
1290                                     handle->cur->entries[handle->k]) {
1291                                         goto out_finish;
1292                                 } else {
1293                                         eof = 1;
1294                                         break;
1295                                 }
1296                         }
1297                         if (++ring >= ring_size)
1298                                 ring = 0;
1299                 }
1300                 asked += i;
1301                 want -= i;
1302
1303                 /*
1304                  * We are out of data, wait for some more.
1305                  */
1306                 if (!have) {
1307                         if (!asked)
1308                                 break;
1309
1310                         ret = hib_wait_io(&hb);
1311                         if (ret)
1312                                 goto out_finish;
1313                         have += asked;
1314                         asked = 0;
1315                         if (eof)
1316                                 eof = 2;
1317                 }
1318
1319                 if (crc->run_threads) {
1320                         wait_event(crc->done, atomic_read(&crc->stop));
1321                         atomic_set(&crc->stop, 0);
1322                         crc->run_threads = 0;
1323                 }
1324
1325                 for (thr = 0; have && thr < nr_threads; thr++) {
1326                         data[thr].cmp_len = *(size_t *)page[pg];
1327                         if (unlikely(!data[thr].cmp_len ||
1328                                      data[thr].cmp_len >
1329                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1330                                 printk(KERN_ERR
1331                                        "PM: Invalid LZO compressed length\n");
1332                                 ret = -1;
1333                                 goto out_finish;
1334                         }
1335
1336                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1337                                             PAGE_SIZE);
1338                         if (need > have) {
1339                                 if (eof > 1) {
1340                                         ret = -1;
1341                                         goto out_finish;
1342                                 }
1343                                 break;
1344                         }
1345
1346                         for (off = 0;
1347                              off < LZO_HEADER + data[thr].cmp_len;
1348                              off += PAGE_SIZE) {
1349                                 memcpy(data[thr].cmp + off,
1350                                        page[pg], PAGE_SIZE);
1351                                 have--;
1352                                 want++;
1353                                 if (++pg >= ring_size)
1354                                         pg = 0;
1355                         }
1356
1357                         atomic_set(&data[thr].ready, 1);
1358                         wake_up(&data[thr].go);
1359                 }
1360
1361                 /*
1362                  * Wait for more data while we are decompressing.
1363                  */
1364                 if (have < LZO_CMP_PAGES && asked) {
1365                         ret = hib_wait_io(&hb);
1366                         if (ret)
1367                                 goto out_finish;
1368                         have += asked;
1369                         asked = 0;
1370                         if (eof)
1371                                 eof = 2;
1372                 }
1373
1374                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1375                         wait_event(data[thr].done,
1376                                    atomic_read(&data[thr].stop));
1377                         atomic_set(&data[thr].stop, 0);
1378
1379                         ret = data[thr].ret;
1380
1381                         if (ret < 0) {
1382                                 printk(KERN_ERR
1383                                        "PM: LZO decompression failed\n");
1384                                 goto out_finish;
1385                         }
1386
1387                         if (unlikely(!data[thr].unc_len ||
1388                                      data[thr].unc_len > LZO_UNC_SIZE ||
1389                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1390                                 printk(KERN_ERR
1391                                        "PM: Invalid LZO uncompressed length\n");
1392                                 ret = -1;
1393                                 goto out_finish;
1394                         }
1395
1396                         for (off = 0;
1397                              off < data[thr].unc_len; off += PAGE_SIZE) {
1398                                 memcpy(data_of(*snapshot),
1399                                        data[thr].unc + off, PAGE_SIZE);
1400
1401                                 if (!(nr_pages % m))
1402                                         printk(KERN_INFO
1403                                                "PM: Image loading progress: "
1404                                                "%3d%%\n",
1405                                                nr_pages / m * 10);
1406                                 nr_pages++;
1407
1408                                 ret = snapshot_write_next(snapshot);
1409                                 if (ret <= 0) {
1410                                         crc->run_threads = thr + 1;
1411                                         atomic_set(&crc->ready, 1);
1412                                         wake_up(&crc->go);
1413                                         goto out_finish;
1414                                 }
1415                         }
1416                 }
1417
1418                 crc->run_threads = thr;
1419                 atomic_set(&crc->ready, 1);
1420                 wake_up(&crc->go);
1421         }
1422
1423 out_finish:
1424         if (crc->run_threads) {
1425                 wait_event(crc->done, atomic_read(&crc->stop));
1426                 atomic_set(&crc->stop, 0);
1427         }
1428         stop = ktime_get();
1429         if (!ret) {
1430                 printk(KERN_INFO "PM: Image loading done.\n");
1431                 snapshot_write_finalize(snapshot);
1432                 if (!snapshot_image_loaded(snapshot))
1433                         ret = -ENODATA;
1434                 if (!ret) {
1435                         if (swsusp_header->flags & SF_CRC32_MODE) {
1436                                 if(handle->crc32 != swsusp_header->crc32) {
1437                                         printk(KERN_ERR
1438                                                "PM: Invalid image CRC32!\n");
1439                                         ret = -ENODATA;
1440                                 }
1441                         }
1442                 }
1443         }
1444         swsusp_show_speed(start, stop, nr_to_read, "Read");
1445 out_clean:
1446         for (i = 0; i < ring_size; i++)
1447                 free_page((unsigned long)page[i]);
1448         if (crc) {
1449                 if (crc->thr)
1450                         kthread_stop(crc->thr);
1451                 kfree(crc);
1452         }
1453         if (data) {
1454                 for (thr = 0; thr < nr_threads; thr++)
1455                         if (data[thr].thr)
1456                                 kthread_stop(data[thr].thr);
1457                 vfree(data);
1458         }
1459         vfree(page);
1460
1461         return ret;
1462 }
1463
1464 /**
1465  *      swsusp_read - read the hibernation image.
1466  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1467  *                be written into this memory location
1468  */
1469
1470 int swsusp_read(unsigned int *flags_p)
1471 {
1472         int error;
1473         struct swap_map_handle handle;
1474         struct snapshot_handle snapshot;
1475         struct swsusp_info *header;
1476
1477         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1478         error = snapshot_write_next(&snapshot);
1479         if (error < PAGE_SIZE)
1480                 return error < 0 ? error : -EFAULT;
1481         header = (struct swsusp_info *)data_of(snapshot);
1482         error = get_swap_reader(&handle, flags_p);
1483         if (error)
1484                 goto end;
1485         if (!error)
1486                 error = swap_read_page(&handle, header, NULL);
1487         if (!error) {
1488                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1489                         load_image(&handle, &snapshot, header->pages - 1) :
1490                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1491         }
1492         swap_reader_finish(&handle);
1493 end:
1494         if (!error)
1495                 pr_debug("PM: Image successfully loaded\n");
1496         else
1497                 pr_debug("PM: Error %d resuming\n", error);
1498         return error;
1499 }
1500
1501 /**
1502  *      swsusp_check - Check for swsusp signature in the resume device
1503  */
1504
1505 int swsusp_check(void)
1506 {
1507         int error;
1508
1509         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1510                                             FMODE_READ, NULL);
1511         if (!IS_ERR(hib_resume_bdev)) {
1512                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1513                 clear_page(swsusp_header);
1514                 error = hib_submit_io(READ_SYNC, swsusp_resume_block,
1515                                         swsusp_header, NULL);
1516                 if (error)
1517                         goto put;
1518
1519                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1520                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1521                         /* Reset swap signature now */
1522                         error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
1523                                                 swsusp_header, NULL);
1524                 } else {
1525                         error = -EINVAL;
1526                 }
1527
1528 put:
1529                 if (error)
1530                         blkdev_put(hib_resume_bdev, FMODE_READ);
1531                 else
1532                         pr_debug("PM: Image signature found, resuming\n");
1533         } else {
1534                 error = PTR_ERR(hib_resume_bdev);
1535         }
1536
1537         if (error)
1538                 pr_debug("PM: Image not found (code %d)\n", error);
1539
1540         return error;
1541 }
1542
1543 /**
1544  *      swsusp_close - close swap device.
1545  */
1546
1547 void swsusp_close(fmode_t mode)
1548 {
1549         if (IS_ERR(hib_resume_bdev)) {
1550                 pr_debug("PM: Image device not initialised\n");
1551                 return;
1552         }
1553
1554         blkdev_put(hib_resume_bdev, mode);
1555 }
1556
1557 /**
1558  *      swsusp_unmark - Unmark swsusp signature in the resume device
1559  */
1560
1561 #ifdef CONFIG_SUSPEND
1562 int swsusp_unmark(void)
1563 {
1564         int error;
1565
1566         hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
1567         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1568                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1569                 error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
1570                                         swsusp_header, NULL);
1571         } else {
1572                 printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
1573                 error = -ENODEV;
1574         }
1575
1576         /*
1577          * We just returned from suspend, we don't need the image any more.
1578          */
1579         free_all_swap_pages(root_swap);
1580
1581         return error;
1582 }
1583 #endif
1584
1585 static int swsusp_header_init(void)
1586 {
1587         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1588         if (!swsusp_header)
1589                 panic("Could not allocate memory for swsusp_header\n");
1590         return 0;
1591 }
1592
1593 core_initcall(swsusp_header_init);