kernel/power/swap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/kernel/power/swap.c
   4  *
   5  * This file provides functions for reading the suspend image from
   6  * and writing it to a swap partition.
   7  *
   8  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
   9  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
  10  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
  11  */
  12
  13 #define pr_fmt(fmt) "PM: " fmt
  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  * When reading an {un,}compressed image, we may restore pages in place,
  41  * in which case some architectures need these pages cleaning before they
  42  * can be executed. We don't know which pages these may be, so clean the lot.
  43  */
  44 static bool clean_pages_on_read;
  45 static bool clean_pages_on_decompress;
  46
  47 /*
  48  *      The swap map is a data structure used for keeping track of each page
  49  *      written to a swap partition.  It consists of many swap_map_page
  50  *      structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
  51  *      These structures are stored on the swap and linked together with the
  52  *      help of the .next_swap member.
  53  *
  54  *      The swap map is created during suspend.  The swap map pages are
  55  *      allocated and populated one at a time, so we only need one memory
  56  *      page to set up the entire structure.
  57  *
  58  *      During resume we pick up all swap_map_page structures into a list.
  59  */
  60
  61 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
  62
  63 /*
  64  * Number of free pages that are not high.
  65  */
  66 static inline unsigned long low_free_pages(void)
  67 {
  68         return nr_free_pages() - nr_free_highpages();
  69 }
  70
  71 /*
  72  * Number of pages required to be kept free while writing the image. Always
  73  * half of all available low pages before the writing starts.
  74  */
  75 static inline unsigned long reqd_free_pages(void)
  76 {
  77         return low_free_pages() / 2;
  78 }
  79
  80 struct swap_map_page {
  81         sector_t entries[MAP_PAGE_ENTRIES];
  82         sector_t next_swap;
  83 };
  84
  85 struct swap_map_page_list {
  86         struct swap_map_page *map;
  87         struct swap_map_page_list *next;
  88 };
  89
  90 /**
  91  *      The swap_map_handle structure is used for handling swap in
  92  *      a file-alike way
  93  */
  94
  95 struct swap_map_handle {
  96         struct swap_map_page *cur;
  97         struct swap_map_page_list *maps;
  98         sector_t cur_swap;
  99         sector_t first_sector;
 100         unsigned int k;
 101         unsigned long reqd_free_pages;
 102         u32 crc32;
 103 };
 104
 105 struct swsusp_header {
 106         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
 107                       sizeof(u32)];
 108         u32     crc32;
 109         sector_t image;
 110         unsigned int flags;     /* Flags to pass to the "boot" kernel */
 111         char    orig_sig[10];
 112         char    sig[10];
 113 } __packed;
 114
 115 static struct swsusp_header *swsusp_header;
 116
 117 /**
 118  *      The following functions are used for tracing the allocated
 119  *      swap pages, so that they can be freed in case of an error.
 120  */
 121
 122 struct swsusp_extent {
 123         struct rb_node node;
 124         unsigned long start;
 125         unsigned long end;
 126 };
 127
 128 static struct rb_root swsusp_extents = RB_ROOT;
 129
 130 static int swsusp_extents_insert(unsigned long swap_offset)
 131 {
 132         struct rb_node **new = &(swsusp_extents.rb_node);
 133         struct rb_node *parent = NULL;
 134         struct swsusp_extent *ext;
 135
 136         /* Figure out where to put the new node */
 137         while (*new) {
 138                 ext = rb_entry(*new, struct swsusp_extent, node);
 139                 parent = *new;
 140                 if (swap_offset < ext->start) {
 141                         /* Try to merge */
 142                         if (swap_offset == ext->start - 1) {
 143                                 ext->start--;
 144                                 return 0;
 145                         }
 146                         new = &((*new)->rb_left);
 147                 } else if (swap_offset > ext->end) {
 148                         /* Try to merge */
 149                         if (swap_offset == ext->end + 1) {
 150                                 ext->end++;
 151                                 return 0;
 152                         }
 153                         new = &((*new)->rb_right);
 154                 } else {
 155                         /* It already is in the tree */
 156                         return -EINVAL;
 157                 }
 158         }
 159         /* Add the new node and rebalance the tree. */
 160         ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
 161         if (!ext)
 162                 return -ENOMEM;
 163
 164         ext->start = swap_offset;
 165         ext->end = swap_offset;
 166         rb_link_node(&ext->node, parent, new);
 167         rb_insert_color(&ext->node, &swsusp_extents);
 168         return 0;
 169 }
 170
 171 /**
 172  *      alloc_swapdev_block - allocate a swap page and register that it has
 173  *      been allocated, so that it can be freed in case of an error.
 174  */
 175
 176 sector_t alloc_swapdev_block(int swap)
 177 {
 178         unsigned long offset;
 179
 180         offset = swp_offset(get_swap_page_of_type(swap));
 181         if (offset) {
 182                 if (swsusp_extents_insert(offset))
 183                         swap_free(swp_entry(swap, offset));
 184                 else
 185                         return swapdev_block(swap, offset);
 186         }
 187         return 0;
 188 }
 189
 190 /**
 191  *      free_all_swap_pages - free swap pages allocated for saving image data.
 192  *      It also frees the extents used to register which swap entries had been
 193  *      allocated.
 194  */
 195
 196 void free_all_swap_pages(int swap)
 197 {
 198         struct rb_node *node;
 199
 200         while ((node = swsusp_extents.rb_node)) {
 201                 struct swsusp_extent *ext;
 202                 unsigned long offset;
 203
 204                 ext = rb_entry(node, struct swsusp_extent, node);
 205                 rb_erase(node, &swsusp_extents);
 206                 for (offset = ext->start; offset <= ext->end; offset++)
 207                         swap_free(swp_entry(swap, offset));
 208
 209                 kfree(ext);
 210         }
 211 }
 212
 213 int swsusp_swap_in_use(void)
 214 {
 215         return (swsusp_extents.rb_node != NULL);
 216 }
 217
 218 /*
 219  * General things
 220  */
 221
 222 static unsigned short root_swap = 0xffff;
 223 static struct block_device *hib_resume_bdev;
 224
 225 struct hib_bio_batch {
 226         atomic_t                count;
 227         wait_queue_head_t       wait;
 228         blk_status_t            error;
 229 };
 230
 231 static void hib_init_batch(struct hib_bio_batch *hb)
 232 {
 233         atomic_set(&hb->count, 0);
 234         init_waitqueue_head(&hb->wait);
 235         hb->error = BLK_STS_OK;
 236 }
 237
 238 static void hib_end_io(struct bio *bio)
 239 {
 240         struct hib_bio_batch *hb = bio->bi_private;
 241         struct page *page = bio_first_page_all(bio);
 242
 243         if (bio->bi_status) {
 244                 pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
 245                          MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
 246                          (unsigned long long)bio->bi_iter.bi_sector);
 247         }
 248
 249         if (bio_data_dir(bio) == WRITE)
 250                 put_page(page);
 251         else if (clean_pages_on_read)
 252                 flush_icache_range((unsigned long)page_address(page),
 253                                    (unsigned long)page_address(page) + PAGE_SIZE);
 254
 255         if (bio->bi_status && !hb->error)
 256                 hb->error = bio->bi_status;
 257         if (atomic_dec_and_test(&hb->count))
 258                 wake_up(&hb->wait);
 259
 260         bio_put(bio);
 261 }
 262
 263 static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,
 264                 struct hib_bio_batch *hb)
 265 {
 266         struct page *page = virt_to_page(addr);
 267         struct bio *bio;
 268         int error = 0;
 269
 270         bio = bio_alloc(GFP_NOIO | __GFP_HIGH, 1);
 271         bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
 272         bio_set_dev(bio, hib_resume_bdev);
 273         bio_set_op_attrs(bio, op, op_flags);
 274
 275         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
 276                 pr_err("Adding page to bio failed at %llu\n",
 277                        (unsigned long long)bio->bi_iter.bi_sector);
 278                 bio_put(bio);
 279                 return -EFAULT;
 280         }
 281
 282         if (hb) {
 283                 bio->bi_end_io = hib_end_io;
 284                 bio->bi_private = hb;
 285                 atomic_inc(&hb->count);
 286                 submit_bio(bio);
 287         } else {
 288                 error = submit_bio_wait(bio);
 289                 bio_put(bio);
 290         }
 291
 292         return error;
 293 }
 294
 295 static blk_status_t hib_wait_io(struct hib_bio_batch *hb)
 296 {
 297         wait_event(hb->wait, atomic_read(&hb->count) == 0);
 298         return blk_status_to_errno(hb->error);
 299 }
 300
 301 /*
 302  * Saving part
 303  */
 304
 305 static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 306 {
 307         int error;
 308
 309         hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
 310                       swsusp_header, NULL);
 311         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 312             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 313                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 314                 memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
 315                 swsusp_header->image = handle->first_sector;
 316                 swsusp_header->flags = flags;
 317                 if (flags & SF_CRC32_MODE)
 318                         swsusp_header->crc32 = handle->crc32;
 319                 error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
 320                                       swsusp_resume_block, swsusp_header, NULL);
 321         } else {
 322                 pr_err("Swap header not found!\n");
 323                 error = -ENODEV;
 324         }
 325         return error;
 326 }
 327
 328 /**
 329  *      swsusp_swap_check - check if the resume device is a swap device
 330  *      and get its index (if so)
 331  *
 332  *      This is called before saving image
 333  */
 334 static int swsusp_swap_check(void)
 335 {
 336         int res;
 337
 338         if (swsusp_resume_device)
 339                 res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
 340         else
 341                 res = find_first_swap(&swsusp_resume_device);
 342         if (res < 0)
 343                 return res;
 344         root_swap = res;
 345
 346         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
 347                         NULL);
 348         if (IS_ERR(hib_resume_bdev))
 349                 return PTR_ERR(hib_resume_bdev);
 350
 351         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
 352         if (res < 0)
 353                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
 354
 355         return res;
 356 }
 357
 358 /**
 359  *      write_page - Write one page to given swap location.
 360  *      @buf:           Address we're writing.
 361  *      @offset:        Offset of the swap page we're writing to.
 362  *      @hb:            bio completion batch
 363  */
 364
 365 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 366 {
 367         void *src;
 368         int ret;
 369
 370         if (!offset)
 371                 return -ENOSPC;
 372
 373         if (hb) {
 374                 src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
 375                                               __GFP_NORETRY);
 376                 if (src) {
 377                         copy_page(src, buf);
 378                 } else {
 379                         ret = hib_wait_io(hb); /* Free pages */
 380                         if (ret)
 381                                 return ret;
 382                         src = (void *)__get_free_page(GFP_NOIO |
 383                                                       __GFP_NOWARN |
 384                                                       __GFP_NORETRY);
 385                         if (src) {
 386                                 copy_page(src, buf);
 387                         } else {
 388                                 WARN_ON_ONCE(1);
 389                                 hb = NULL;      /* Go synchronous */
 390                                 src = buf;
 391                         }
 392                 }
 393         } else {
 394                 src = buf;
 395         }
 396         return hib_submit_io(REQ_OP_WRITE, REQ_SYNC, offset, src, hb);
 397 }
 398
 399 static void release_swap_writer(struct swap_map_handle *handle)
 400 {
 401         if (handle->cur)
 402                 free_page((unsigned long)handle->cur);
 403         handle->cur = NULL;
 404 }
 405
 406 static int get_swap_writer(struct swap_map_handle *handle)
 407 {
 408         int ret;
 409
 410         ret = swsusp_swap_check();
 411         if (ret) {
 412                 if (ret != -ENOSPC)
 413                         pr_err("Cannot find swap device, try swapon -a\n");
 414                 return ret;
 415         }
 416         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 417         if (!handle->cur) {
 418                 ret = -ENOMEM;
 419                 goto err_close;
 420         }
 421         handle->cur_swap = alloc_swapdev_block(root_swap);
 422         if (!handle->cur_swap) {
 423                 ret = -ENOSPC;
 424                 goto err_rel;
 425         }
 426         handle->k = 0;
 427         handle->reqd_free_pages = reqd_free_pages();
 428         handle->first_sector = handle->cur_swap;
 429         return 0;
 430 err_rel:
 431         release_swap_writer(handle);
 432 err_close:
 433         swsusp_close(FMODE_WRITE);
 434         return ret;
 435 }
 436
 437 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 438                 struct hib_bio_batch *hb)
 439 {
 440         int error = 0;
 441         sector_t offset;
 442
 443         if (!handle->cur)
 444                 return -EINVAL;
 445         offset = alloc_swapdev_block(root_swap);
 446         error = write_page(buf, offset, hb);
 447         if (error)
 448                 return error;
 449         handle->cur->entries[handle->k++] = offset;
 450         if (handle->k >= MAP_PAGE_ENTRIES) {
 451                 offset = alloc_swapdev_block(root_swap);
 452                 if (!offset)
 453                         return -ENOSPC;
 454                 handle->cur->next_swap = offset;
 455                 error = write_page(handle->cur, handle->cur_swap, hb);
 456                 if (error)
 457                         goto out;
 458                 clear_page(handle->cur);
 459                 handle->cur_swap = offset;
 460                 handle->k = 0;
 461
 462                 if (hb && low_free_pages() <= handle->reqd_free_pages) {
 463                         error = hib_wait_io(hb);
 464                         if (error)
 465                                 goto out;
 466                         /*
 467                          * Recalculate the number of required free pages, to
 468                          * make sure we never take more than half.
 469                          */
 470                         handle->reqd_free_pages = reqd_free_pages();
 471                 }
 472         }
 473  out:
 474         return error;
 475 }
 476
 477 static int flush_swap_writer(struct swap_map_handle *handle)
 478 {
 479         if (handle->cur && handle->cur_swap)
 480                 return write_page(handle->cur, handle->cur_swap, NULL);
 481         else
 482                 return -EINVAL;
 483 }
 484
 485 static int swap_writer_finish(struct swap_map_handle *handle,
 486                 unsigned int flags, int error)
 487 {
 488         if (!error) {
 489                 flush_swap_writer(handle);
 490                 pr_info("S");
 491                 error = mark_swapfiles(handle, flags);
 492                 pr_cont("|\n");
 493         }
 494
 495         if (error)
 496                 free_all_swap_pages(root_swap);
 497         release_swap_writer(handle);
 498         swsusp_close(FMODE_WRITE);
 499
 500         return error;
 501 }
 502
 503 /* We need to remember how much compressed data we need to read. */
 504 #define LZO_HEADER      sizeof(size_t)
 505
 506 /* Number of pages/bytes we'll compress at one time. */
 507 #define LZO_UNC_PAGES   32
 508 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
 509
 510 /* Number of pages/bytes we need for compressed data (worst case). */
 511 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
 512                                      LZO_HEADER, PAGE_SIZE)
 513 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
 514
 515 /* Maximum number of threads for compression/decompression. */
 516 #define LZO_THREADS     3
 517
 518 /* Minimum/maximum number of pages for read buffering. */
 519 #define LZO_MIN_RD_PAGES        1024
 520 #define LZO_MAX_RD_PAGES        8192
 521
 522
 523 /**
 524  *      save_image - save the suspend image data
 525  */
 526
 527 static int save_image(struct swap_map_handle *handle,
 528                       struct snapshot_handle *snapshot,
 529                       unsigned int nr_to_write)
 530 {
 531         unsigned int m;
 532         int ret;
 533         int nr_pages;
 534         int err2;
 535         struct hib_bio_batch hb;
 536         ktime_t start;
 537         ktime_t stop;
 538
 539         hib_init_batch(&hb);
 540
 541         pr_info("Saving image data pages (%u pages)...\n",
 542                 nr_to_write);
 543         m = nr_to_write / 10;
 544         if (!m)
 545                 m = 1;
 546         nr_pages = 0;
 547         start = ktime_get();
 548         while (1) {
 549                 ret = snapshot_read_next(snapshot);
 550                 if (ret <= 0)
 551                         break;
 552                 ret = swap_write_page(handle, data_of(*snapshot), &hb);
 553                 if (ret)
 554                         break;
 555                 if (!(nr_pages % m))
 556                         pr_info("Image saving progress: %3d%%\n",
 557                                 nr_pages / m * 10);
 558                 nr_pages++;
 559         }
 560         err2 = hib_wait_io(&hb);
 561         stop = ktime_get();
 562         if (!ret)
 563                 ret = err2;
 564         if (!ret)
 565                 pr_info("Image saving done\n");
 566         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 567         return ret;
 568 }
 569
 570 /**
 571  * Structure used for CRC32.
 572  */
 573 struct crc_data {
 574         struct task_struct *thr;                  /* thread */
 575         atomic_t ready;                           /* ready to start flag */
 576         atomic_t stop;                            /* ready to stop flag */
 577         unsigned run_threads;                     /* nr current threads */
 578         wait_queue_head_t go;                     /* start crc update */
 579         wait_queue_head_t done;                   /* crc update done */
 580         u32 *crc32;                               /* points to handle's crc32 */
 581         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
 582         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
 583 };
 584
 585 /**
 586  * CRC32 update function that runs in its own thread.
 587  */
 588 static int crc32_threadfn(void *data)
 589 {
 590         struct crc_data *d = data;
 591         unsigned i;
 592
 593         while (1) {
 594                 wait_event(d->go, atomic_read(&d->ready) ||
 595                                   kthread_should_stop());
 596                 if (kthread_should_stop()) {
 597                         d->thr = NULL;
 598                         atomic_set(&d->stop, 1);
 599                         wake_up(&d->done);
 600                         break;
 601                 }
 602                 atomic_set(&d->ready, 0);
 603
 604                 for (i = 0; i < d->run_threads; i++)
 605                         *d->crc32 = crc32_le(*d->crc32,
 606                                              d->unc[i], *d->unc_len[i]);
 607                 atomic_set(&d->stop, 1);
 608                 wake_up(&d->done);
 609         }
 610         return 0;
 611 }
 612 /**
 613  * Structure used for LZO data compression.
 614  */
 615 struct cmp_data {
 616         struct task_struct *thr;                  /* thread */
 617         atomic_t ready;                           /* ready to start flag */
 618         atomic_t stop;                            /* ready to stop flag */
 619         int ret;                                  /* return code */
 620         wait_queue_head_t go;                     /* start compression */
 621         wait_queue_head_t done;                   /* compression done */
 622         size_t unc_len;                           /* uncompressed length */
 623         size_t cmp_len;                           /* compressed length */
 624         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
 625         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
 626         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
 627 };
 628
 629 /**
 630  * Compression function that runs in its own thread.
 631  */
 632 static int lzo_compress_threadfn(void *data)
 633 {
 634         struct cmp_data *d = data;
 635
 636         while (1) {
 637                 wait_event(d->go, atomic_read(&d->ready) ||
 638                                   kthread_should_stop());
 639                 if (kthread_should_stop()) {
 640                         d->thr = NULL;
 641                         d->ret = -1;
 642                         atomic_set(&d->stop, 1);
 643                         wake_up(&d->done);
 644                         break;
 645                 }
 646                 atomic_set(&d->ready, 0);
 647
 648                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
 649                                           d->cmp + LZO_HEADER, &d->cmp_len,
 650                                           d->wrk);
 651                 atomic_set(&d->stop, 1);
 652                 wake_up(&d->done);
 653         }
 654         return 0;
 655 }
 656
 657 /**
 658  * save_image_lzo - Save the suspend image data compressed with LZO.
 659  * @handle: Swap map handle to use for saving the image.
 660  * @snapshot: Image to read data from.
 661  * @nr_to_write: Number of pages to save.
 662  */
 663 static int save_image_lzo(struct swap_map_handle *handle,
 664                           struct snapshot_handle *snapshot,
 665                           unsigned int nr_to_write)
 666 {
 667         unsigned int m;
 668         int ret = 0;
 669         int nr_pages;
 670         int err2;
 671         struct hib_bio_batch hb;
 672         ktime_t start;
 673         ktime_t stop;
 674         size_t off;
 675         unsigned thr, run_threads, nr_threads;
 676         unsigned char *page = NULL;
 677         struct cmp_data *data = NULL;
 678         struct crc_data *crc = NULL;
 679
 680         hib_init_batch(&hb);
 681
 682         /*
 683          * We'll limit the number of threads for compression to limit memory
 684          * footprint.
 685          */
 686         nr_threads = num_online_cpus() - 1;
 687         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 688
 689         page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
 690         if (!page) {
 691                 pr_err("Failed to allocate LZO page\n");
 692                 ret = -ENOMEM;
 693                 goto out_clean;
 694         }
 695
 696         data = vmalloc(array_size(nr_threads, sizeof(*data)));
 697         if (!data) {
 698                 pr_err("Failed to allocate LZO data\n");
 699                 ret = -ENOMEM;
 700                 goto out_clean;
 701         }
 702         for (thr = 0; thr < nr_threads; thr++)
 703                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
 704
 705         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
 706         if (!crc) {
 707                 pr_err("Failed to allocate crc\n");
 708                 ret = -ENOMEM;
 709                 goto out_clean;
 710         }
 711         memset(crc, 0, offsetof(struct crc_data, go));
 712
 713         /*
 714          * Start the compression threads.
 715          */
 716         for (thr = 0; thr < nr_threads; thr++) {
 717                 init_waitqueue_head(&data[thr].go);
 718                 init_waitqueue_head(&data[thr].done);
 719
 720                 data[thr].thr = kthread_run(lzo_compress_threadfn,
 721                                             &data[thr],
 722                                             "image_compress/%u", thr);
 723                 if (IS_ERR(data[thr].thr)) {
 724                         data[thr].thr = NULL;
 725                         pr_err("Cannot start compression threads\n");
 726                         ret = -ENOMEM;
 727                         goto out_clean;
 728                 }
 729         }
 730
 731         /*
 732          * Start the CRC32 thread.
 733          */
 734         init_waitqueue_head(&crc->go);
 735         init_waitqueue_head(&crc->done);
 736
 737         handle->crc32 = 0;
 738         crc->crc32 = &handle->crc32;
 739         for (thr = 0; thr < nr_threads; thr++) {
 740                 crc->unc[thr] = data[thr].unc;
 741                 crc->unc_len[thr] = &data[thr].unc_len;
 742         }
 743
 744         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
 745         if (IS_ERR(crc->thr)) {
 746                 crc->thr = NULL;
 747                 pr_err("Cannot start CRC32 thread\n");
 748                 ret = -ENOMEM;
 749                 goto out_clean;
 750         }
 751
 752         /*
 753          * Adjust the number of required free pages after all allocations have
 754          * been done. We don't want to run out of pages when writing.
 755          */
 756         handle->reqd_free_pages = reqd_free_pages();
 757
 758         pr_info("Using %u thread(s) for compression\n", nr_threads);
 759         pr_info("Compressing and saving image data (%u pages)...\n",
 760                 nr_to_write);
 761         m = nr_to_write / 10;
 762         if (!m)
 763                 m = 1;
 764         nr_pages = 0;
 765         start = ktime_get();
 766         for (;;) {
 767                 for (thr = 0; thr < nr_threads; thr++) {
 768                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
 769                                 ret = snapshot_read_next(snapshot);
 770                                 if (ret < 0)
 771                                         goto out_finish;
 772
 773                                 if (!ret)
 774                                         break;
 775
 776                                 memcpy(data[thr].unc + off,
 777                                        data_of(*snapshot), PAGE_SIZE);
 778
 779                                 if (!(nr_pages % m))
 780                                         pr_info("Image saving progress: %3d%%\n",
 781                                                 nr_pages / m * 10);
 782                                 nr_pages++;
 783                         }
 784                         if (!off)
 785                                 break;
 786
 787                         data[thr].unc_len = off;
 788
 789                         atomic_set(&data[thr].ready, 1);
 790                         wake_up(&data[thr].go);
 791                 }
 792
 793                 if (!thr)
 794                         break;
 795
 796                 crc->run_threads = thr;
 797                 atomic_set(&crc->ready, 1);
 798                 wake_up(&crc->go);
 799
 800                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
 801                         wait_event(data[thr].done,
 802                                    atomic_read(&data[thr].stop));
 803                         atomic_set(&data[thr].stop, 0);
 804
 805                         ret = data[thr].ret;
 806
 807                         if (ret < 0) {
 808                                 pr_err("LZO compression failed\n");
 809                                 goto out_finish;
 810                         }
 811
 812                         if (unlikely(!data[thr].cmp_len ||
 813                                      data[thr].cmp_len >
 814                                      lzo1x_worst_compress(data[thr].unc_len))) {
 815                                 pr_err("Invalid LZO compressed length\n");
 816                                 ret = -1;
 817                                 goto out_finish;
 818                         }
 819
 820                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
 821
 822                         /*
 823                          * Given we are writing one page at a time to disk, we
 824                          * copy that much from the buffer, although the last
 825                          * bit will likely be smaller than full page. This is
 826                          * OK - we saved the length of the compressed data, so
 827                          * any garbage at the end will be discarded when we
 828                          * read it.
 829                          */
 830                         for (off = 0;
 831                              off < LZO_HEADER + data[thr].cmp_len;
 832                              off += PAGE_SIZE) {
 833                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
 834
 835                                 ret = swap_write_page(handle, page, &hb);
 836                                 if (ret)
 837                                         goto out_finish;
 838                         }
 839                 }
 840
 841                 wait_event(crc->done, atomic_read(&crc->stop));
 842                 atomic_set(&crc->stop, 0);
 843         }
 844
 845 out_finish:
 846         err2 = hib_wait_io(&hb);
 847         stop = ktime_get();
 848         if (!ret)
 849                 ret = err2;
 850         if (!ret)
 851                 pr_info("Image saving done\n");
 852         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 853 out_clean:
 854         if (crc) {
 855                 if (crc->thr)
 856                         kthread_stop(crc->thr);
 857                 kfree(crc);
 858         }
 859         if (data) {
 860                 for (thr = 0; thr < nr_threads; thr++)
 861                         if (data[thr].thr)
 862                                 kthread_stop(data[thr].thr);
 863                 vfree(data);
 864         }
 865         if (page) free_page((unsigned long)page);
 866
 867         return ret;
 868 }
 869
 870 /**
 871  *      enough_swap - Make sure we have enough swap to save the image.
 872  *
 873  *      Returns TRUE or FALSE after checking the total amount of swap
 874  *      space avaiable from the resume partition.
 875  */
 876
 877 static int enough_swap(unsigned int nr_pages)
 878 {
 879         unsigned int free_swap = count_swap_pages(root_swap, 1);
 880         unsigned int required;
 881
 882         pr_debug("Free swap pages: %u\n", free_swap);
 883
 884         required = PAGES_FOR_IO + nr_pages;
 885         return free_swap > required;
 886 }
 887
 888 /**
 889  *      swsusp_write - Write entire image and metadata.
 890  *      @flags: flags to pass to the "boot" kernel in the image header
 891  *
 892  *      It is important _NOT_ to umount filesystems at this point. We want
 893  *      them synced (in case something goes wrong) but we DO not want to mark
 894  *      filesystem clean: it is not. (And it does not matter, if we resume
 895  *      correctly, we'll mark system clean, anyway.)
 896  */
 897
 898 int swsusp_write(unsigned int flags)
 899 {
 900         struct swap_map_handle handle;
 901         struct snapshot_handle snapshot;
 902         struct swsusp_info *header;
 903         unsigned long pages;
 904         int error;
 905
 906         pages = snapshot_get_image_size();
 907         error = get_swap_writer(&handle);
 908         if (error) {
 909                 pr_err("Cannot get swap writer\n");
 910                 return error;
 911         }
 912         if (flags & SF_NOCOMPRESS_MODE) {
 913                 if (!enough_swap(pages)) {
 914                         pr_err("Not enough free swap\n");
 915                         error = -ENOSPC;
 916                         goto out_finish;
 917                 }
 918         }
 919         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 920         error = snapshot_read_next(&snapshot);
 921         if (error < (int)PAGE_SIZE) {
 922                 if (error >= 0)
 923                         error = -EFAULT;
 924
 925                 goto out_finish;
 926         }
 927         header = (struct swsusp_info *)data_of(snapshot);
 928         error = swap_write_page(&handle, header, NULL);
 929         if (!error) {
 930                 error = (flags & SF_NOCOMPRESS_MODE) ?
 931                         save_image(&handle, &snapshot, pages - 1) :
 932                         save_image_lzo(&handle, &snapshot, pages - 1);
 933         }
 934 out_finish:
 935         error = swap_writer_finish(&handle, flags, error);
 936         return error;
 937 }
 938
 939 /**
 940  *      The following functions allow us to read data using a swap map
 941  *      in a file-alike way
 942  */
 943
 944 static void release_swap_reader(struct swap_map_handle *handle)
 945 {
 946         struct swap_map_page_list *tmp;
 947
 948         while (handle->maps) {
 949                 if (handle->maps->map)
 950                         free_page((unsigned long)handle->maps->map);
 951                 tmp = handle->maps;
 952                 handle->maps = handle->maps->next;
 953                 kfree(tmp);
 954         }
 955         handle->cur = NULL;
 956 }
 957
 958 static int get_swap_reader(struct swap_map_handle *handle,
 959                 unsigned int *flags_p)
 960 {
 961         int error;
 962         struct swap_map_page_list *tmp, *last;
 963         sector_t offset;
 964
 965         *flags_p = swsusp_header->flags;
 966
 967         if (!swsusp_header->image) /* how can this happen? */
 968                 return -EINVAL;
 969
 970         handle->cur = NULL;
 971         last = handle->maps = NULL;
 972         offset = swsusp_header->image;
 973         while (offset) {
 974                 tmp = kzalloc(sizeof(*handle->maps), GFP_KERNEL);
 975                 if (!tmp) {
 976                         release_swap_reader(handle);
 977                         return -ENOMEM;
 978                 }
 979                 if (!handle->maps)
 980                         handle->maps = tmp;
 981                 if (last)
 982                         last->next = tmp;
 983                 last = tmp;
 984
 985                 tmp->map = (struct swap_map_page *)
 986                            __get_free_page(GFP_NOIO | __GFP_HIGH);
 987                 if (!tmp->map) {
 988                         release_swap_reader(handle);
 989                         return -ENOMEM;
 990                 }
 991
 992                 error = hib_submit_io(REQ_OP_READ, 0, offset, tmp->map, NULL);
 993                 if (error) {
 994                         release_swap_reader(handle);
 995                         return error;
 996                 }
 997                 offset = tmp->map->next_swap;
 998         }
 999         handle->k = 0;
1000         handle->cur = handle->maps->map;
1001         return 0;
1002 }
1003
1004 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1005                 struct hib_bio_batch *hb)
1006 {
1007         sector_t offset;
1008         int error;
1009         struct swap_map_page_list *tmp;
1010
1011         if (!handle->cur)
1012                 return -EINVAL;
1013         offset = handle->cur->entries[handle->k];
1014         if (!offset)
1015                 return -EFAULT;
1016         error = hib_submit_io(REQ_OP_READ, 0, offset, buf, hb);
1017         if (error)
1018                 return error;
1019         if (++handle->k >= MAP_PAGE_ENTRIES) {
1020                 handle->k = 0;
1021                 free_page((unsigned long)handle->maps->map);
1022                 tmp = handle->maps;
1023                 handle->maps = handle->maps->next;
1024                 kfree(tmp);
1025                 if (!handle->maps)
1026                         release_swap_reader(handle);
1027                 else
1028                         handle->cur = handle->maps->map;
1029         }
1030         return error;
1031 }
1032
1033 static int swap_reader_finish(struct swap_map_handle *handle)
1034 {
1035         release_swap_reader(handle);
1036
1037         return 0;
1038 }
1039
1040 /**
1041  *      load_image - load the image using the swap map handle
1042  *      @handle and the snapshot handle @snapshot
1043  *      (assume there are @nr_pages pages to load)
1044  */
1045
1046 static int load_image(struct swap_map_handle *handle,
1047                       struct snapshot_handle *snapshot,
1048                       unsigned int nr_to_read)
1049 {
1050         unsigned int m;
1051         int ret = 0;
1052         ktime_t start;
1053         ktime_t stop;
1054         struct hib_bio_batch hb;
1055         int err2;
1056         unsigned nr_pages;
1057
1058         hib_init_batch(&hb);
1059
1060         clean_pages_on_read = true;
1061         pr_info("Loading image data pages (%u pages)...\n", nr_to_read);
1062         m = nr_to_read / 10;
1063         if (!m)
1064                 m = 1;
1065         nr_pages = 0;
1066         start = ktime_get();
1067         for ( ; ; ) {
1068                 ret = snapshot_write_next(snapshot);
1069                 if (ret <= 0)
1070                         break;
1071                 ret = swap_read_page(handle, data_of(*snapshot), &hb);
1072                 if (ret)
1073                         break;
1074                 if (snapshot->sync_read)
1075                         ret = hib_wait_io(&hb);
1076                 if (ret)
1077                         break;
1078                 if (!(nr_pages % m))
1079                         pr_info("Image loading progress: %3d%%\n",
1080                                 nr_pages / m * 10);
1081                 nr_pages++;
1082         }
1083         err2 = hib_wait_io(&hb);
1084         stop = ktime_get();
1085         if (!ret)
1086                 ret = err2;
1087         if (!ret) {
1088                 pr_info("Image loading done\n");
1089                 snapshot_write_finalize(snapshot);
1090                 if (!snapshot_image_loaded(snapshot))
1091                         ret = -ENODATA;
1092         }
1093         swsusp_show_speed(start, stop, nr_to_read, "Read");
1094         return ret;
1095 }
1096
1097 /**
1098  * Structure used for LZO data decompression.
1099  */
1100 struct dec_data {
1101         struct task_struct *thr;                  /* thread */
1102         atomic_t ready;                           /* ready to start flag */
1103         atomic_t stop;                            /* ready to stop flag */
1104         int ret;                                  /* return code */
1105         wait_queue_head_t go;                     /* start decompression */
1106         wait_queue_head_t done;                   /* decompression done */
1107         size_t unc_len;                           /* uncompressed length */
1108         size_t cmp_len;                           /* compressed length */
1109         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1110         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1111 };
1112
1113 /**
1114  * Deompression function that runs in its own thread.
1115  */
1116 static int lzo_decompress_threadfn(void *data)
1117 {
1118         struct dec_data *d = data;
1119
1120         while (1) {
1121                 wait_event(d->go, atomic_read(&d->ready) ||
1122                                   kthread_should_stop());
1123                 if (kthread_should_stop()) {
1124                         d->thr = NULL;
1125                         d->ret = -1;
1126                         atomic_set(&d->stop, 1);
1127                         wake_up(&d->done);
1128                         break;
1129                 }
1130                 atomic_set(&d->ready, 0);
1131
1132                 d->unc_len = LZO_UNC_SIZE;
1133                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1134                                                d->unc, &d->unc_len);
1135                 if (clean_pages_on_decompress)
1136                         flush_icache_range((unsigned long)d->unc,
1137                                            (unsigned long)d->unc + d->unc_len);
1138
1139                 atomic_set(&d->stop, 1);
1140                 wake_up(&d->done);
1141         }
1142         return 0;
1143 }
1144
1145 /**
1146  * load_image_lzo - Load compressed image data and decompress them with LZO.
1147  * @handle: Swap map handle to use for loading data.
1148  * @snapshot: Image to copy uncompressed data into.
1149  * @nr_to_read: Number of pages to load.
1150  */
1151 static int load_image_lzo(struct swap_map_handle *handle,
1152                           struct snapshot_handle *snapshot,
1153                           unsigned int nr_to_read)
1154 {
1155         unsigned int m;
1156         int ret = 0;
1157         int eof = 0;
1158         struct hib_bio_batch hb;
1159         ktime_t start;
1160         ktime_t stop;
1161         unsigned nr_pages;
1162         size_t off;
1163         unsigned i, thr, run_threads, nr_threads;
1164         unsigned ring = 0, pg = 0, ring_size = 0,
1165                  have = 0, want, need, asked = 0;
1166         unsigned long read_pages = 0;
1167         unsigned char **page = NULL;
1168         struct dec_data *data = NULL;
1169         struct crc_data *crc = NULL;
1170
1171         hib_init_batch(&hb);
1172
1173         /*
1174          * We'll limit the number of threads for decompression to limit memory
1175          * footprint.
1176          */
1177         nr_threads = num_online_cpus() - 1;
1178         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1179
1180         page = vmalloc(array_size(LZO_MAX_RD_PAGES, sizeof(*page)));
1181         if (!page) {
1182                 pr_err("Failed to allocate LZO page\n");
1183                 ret = -ENOMEM;
1184                 goto out_clean;
1185         }
1186
1187         data = vmalloc(array_size(nr_threads, sizeof(*data)));
1188         if (!data) {
1189                 pr_err("Failed to allocate LZO data\n");
1190                 ret = -ENOMEM;
1191                 goto out_clean;
1192         }
1193         for (thr = 0; thr < nr_threads; thr++)
1194                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1195
1196         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1197         if (!crc) {
1198                 pr_err("Failed to allocate crc\n");
1199                 ret = -ENOMEM;
1200                 goto out_clean;
1201         }
1202         memset(crc, 0, offsetof(struct crc_data, go));
1203
1204         clean_pages_on_decompress = true;
1205
1206         /*
1207          * Start the decompression threads.
1208          */
1209         for (thr = 0; thr < nr_threads; thr++) {
1210                 init_waitqueue_head(&data[thr].go);
1211                 init_waitqueue_head(&data[thr].done);
1212
1213                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1214                                             &data[thr],
1215                                             "image_decompress/%u", thr);
1216                 if (IS_ERR(data[thr].thr)) {
1217                         data[thr].thr = NULL;
1218                         pr_err("Cannot start decompression threads\n");
1219                         ret = -ENOMEM;
1220                         goto out_clean;
1221                 }
1222         }
1223
1224         /*
1225          * Start the CRC32 thread.
1226          */
1227         init_waitqueue_head(&crc->go);
1228         init_waitqueue_head(&crc->done);
1229
1230         handle->crc32 = 0;
1231         crc->crc32 = &handle->crc32;
1232         for (thr = 0; thr < nr_threads; thr++) {
1233                 crc->unc[thr] = data[thr].unc;
1234                 crc->unc_len[thr] = &data[thr].unc_len;
1235         }
1236
1237         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1238         if (IS_ERR(crc->thr)) {
1239                 crc->thr = NULL;
1240                 pr_err("Cannot start CRC32 thread\n");
1241                 ret = -ENOMEM;
1242                 goto out_clean;
1243         }
1244
1245         /*
1246          * Set the number of pages for read buffering.
1247          * This is complete guesswork, because we'll only know the real
1248          * picture once prepare_image() is called, which is much later on
1249          * during the image load phase. We'll assume the worst case and
1250          * say that none of the image pages are from high memory.
1251          */
1252         if (low_free_pages() > snapshot_get_image_size())
1253                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1254         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1255
1256         for (i = 0; i < read_pages; i++) {
1257                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1258                                                   GFP_NOIO | __GFP_HIGH :
1259                                                   GFP_NOIO | __GFP_NOWARN |
1260                                                   __GFP_NORETRY);
1261
1262                 if (!page[i]) {
1263                         if (i < LZO_CMP_PAGES) {
1264                                 ring_size = i;
1265                                 pr_err("Failed to allocate LZO pages\n");
1266                                 ret = -ENOMEM;
1267                                 goto out_clean;
1268                         } else {
1269                                 break;
1270                         }
1271                 }
1272         }
1273         want = ring_size = i;
1274
1275         pr_info("Using %u thread(s) for decompression\n", nr_threads);
1276         pr_info("Loading and decompressing image data (%u pages)...\n",
1277                 nr_to_read);
1278         m = nr_to_read / 10;
1279         if (!m)
1280                 m = 1;
1281         nr_pages = 0;
1282         start = ktime_get();
1283
1284         ret = snapshot_write_next(snapshot);
1285         if (ret <= 0)
1286                 goto out_finish;
1287
1288         for(;;) {
1289                 for (i = 0; !eof && i < want; i++) {
1290                         ret = swap_read_page(handle, page[ring], &hb);
1291                         if (ret) {
1292                                 /*
1293                                  * On real read error, finish. On end of data,
1294                                  * set EOF flag and just exit the read loop.
1295                                  */
1296                                 if (handle->cur &&
1297                                     handle->cur->entries[handle->k]) {
1298                                         goto out_finish;
1299                                 } else {
1300                                         eof = 1;
1301                                         break;
1302                                 }
1303                         }
1304                         if (++ring >= ring_size)
1305                                 ring = 0;
1306                 }
1307                 asked += i;
1308                 want -= i;
1309
1310                 /*
1311                  * We are out of data, wait for some more.
1312                  */
1313                 if (!have) {
1314                         if (!asked)
1315                                 break;
1316
1317                         ret = hib_wait_io(&hb);
1318                         if (ret)
1319                                 goto out_finish;
1320                         have += asked;
1321                         asked = 0;
1322                         if (eof)
1323                                 eof = 2;
1324                 }
1325
1326                 if (crc->run_threads) {
1327                         wait_event(crc->done, atomic_read(&crc->stop));
1328                         atomic_set(&crc->stop, 0);
1329                         crc->run_threads = 0;
1330                 }
1331
1332                 for (thr = 0; have && thr < nr_threads; thr++) {
1333                         data[thr].cmp_len = *(size_t *)page[pg];
1334                         if (unlikely(!data[thr].cmp_len ||
1335                                      data[thr].cmp_len >
1336                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1337                                 pr_err("Invalid LZO compressed length\n");
1338                                 ret = -1;
1339                                 goto out_finish;
1340                         }
1341
1342                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1343                                             PAGE_SIZE);
1344                         if (need > have) {
1345                                 if (eof > 1) {
1346                                         ret = -1;
1347                                         goto out_finish;
1348                                 }
1349                                 break;
1350                         }
1351
1352                         for (off = 0;
1353                              off < LZO_HEADER + data[thr].cmp_len;
1354                              off += PAGE_SIZE) {
1355                                 memcpy(data[thr].cmp + off,
1356                                        page[pg], PAGE_SIZE);
1357                                 have--;
1358                                 want++;
1359                                 if (++pg >= ring_size)
1360                                         pg = 0;
1361                         }
1362
1363                         atomic_set(&data[thr].ready, 1);
1364                         wake_up(&data[thr].go);
1365                 }
1366
1367                 /*
1368                  * Wait for more data while we are decompressing.
1369                  */
1370                 if (have < LZO_CMP_PAGES && asked) {
1371                         ret = hib_wait_io(&hb);
1372                         if (ret)
1373                                 goto out_finish;
1374                         have += asked;
1375                         asked = 0;
1376                         if (eof)
1377                                 eof = 2;
1378                 }
1379
1380                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1381                         wait_event(data[thr].done,
1382                                    atomic_read(&data[thr].stop));
1383                         atomic_set(&data[thr].stop, 0);
1384
1385                         ret = data[thr].ret;
1386
1387                         if (ret < 0) {
1388                                 pr_err("LZO decompression failed\n");
1389                                 goto out_finish;
1390                         }
1391
1392                         if (unlikely(!data[thr].unc_len ||
1393                                      data[thr].unc_len > LZO_UNC_SIZE ||
1394                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1395                                 pr_err("Invalid LZO uncompressed length\n");
1396                                 ret = -1;
1397                                 goto out_finish;
1398                         }
1399
1400                         for (off = 0;
1401                              off < data[thr].unc_len; off += PAGE_SIZE) {
1402                                 memcpy(data_of(*snapshot),
1403                                        data[thr].unc + off, PAGE_SIZE);
1404
1405                                 if (!(nr_pages % m))
1406                                         pr_info("Image loading progress: %3d%%\n",
1407                                                 nr_pages / m * 10);
1408                                 nr_pages++;
1409
1410                                 ret = snapshot_write_next(snapshot);
1411                                 if (ret <= 0) {
1412                                         crc->run_threads = thr + 1;
1413                                         atomic_set(&crc->ready, 1);
1414                                         wake_up(&crc->go);
1415                                         goto out_finish;
1416                                 }
1417                         }
1418                 }
1419
1420                 crc->run_threads = thr;
1421                 atomic_set(&crc->ready, 1);
1422                 wake_up(&crc->go);
1423         }
1424
1425 out_finish:
1426         if (crc->run_threads) {
1427                 wait_event(crc->done, atomic_read(&crc->stop));
1428                 atomic_set(&crc->stop, 0);
1429         }
1430         stop = ktime_get();
1431         if (!ret) {
1432                 pr_info("Image loading done\n");
1433                 snapshot_write_finalize(snapshot);
1434                 if (!snapshot_image_loaded(snapshot))
1435                         ret = -ENODATA;
1436                 if (!ret) {
1437                         if (swsusp_header->flags & SF_CRC32_MODE) {
1438                                 if(handle->crc32 != swsusp_header->crc32) {
1439                                         pr_err("Invalid image CRC32!\n");
1440                                         ret = -ENODATA;
1441                                 }
1442                         }
1443                 }
1444         }
1445         swsusp_show_speed(start, stop, nr_to_read, "Read");
1446 out_clean:
1447         for (i = 0; i < ring_size; i++)
1448                 free_page((unsigned long)page[i]);
1449         if (crc) {
1450                 if (crc->thr)
1451                         kthread_stop(crc->thr);
1452                 kfree(crc);
1453         }
1454         if (data) {
1455                 for (thr = 0; thr < nr_threads; thr++)
1456                         if (data[thr].thr)
1457                                 kthread_stop(data[thr].thr);
1458                 vfree(data);
1459         }
1460         vfree(page);
1461
1462         return ret;
1463 }
1464
1465 /**
1466  *      swsusp_read - read the hibernation image.
1467  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1468  *                be written into this memory location
1469  */
1470
1471 int swsusp_read(unsigned int *flags_p)
1472 {
1473         int error;
1474         struct swap_map_handle handle;
1475         struct snapshot_handle snapshot;
1476         struct swsusp_info *header;
1477
1478         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1479         error = snapshot_write_next(&snapshot);
1480         if (error < (int)PAGE_SIZE)
1481                 return error < 0 ? error : -EFAULT;
1482         header = (struct swsusp_info *)data_of(snapshot);
1483         error = get_swap_reader(&handle, flags_p);
1484         if (error)
1485                 goto end;
1486         if (!error)
1487                 error = swap_read_page(&handle, header, NULL);
1488         if (!error) {
1489                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1490                         load_image(&handle, &snapshot, header->pages - 1) :
1491                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1492         }
1493         swap_reader_finish(&handle);
1494 end:
1495         if (!error)
1496                 pr_debug("Image successfully loaded\n");
1497         else
1498                 pr_debug("Error %d resuming\n", error);
1499         return error;
1500 }
1501
1502 /**
1503  *      swsusp_check - Check for swsusp signature in the resume device
1504  */
1505
1506 int swsusp_check(void)
1507 {
1508         int error;
1509
1510         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1511                                             FMODE_READ, NULL);
1512         if (!IS_ERR(hib_resume_bdev)) {
1513                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1514                 clear_page(swsusp_header);
1515                 error = hib_submit_io(REQ_OP_READ, 0,
1516                                         swsusp_resume_block,
1517                                         swsusp_header, NULL);
1518                 if (error)
1519                         goto put;
1520
1521                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1522                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1523                         /* Reset swap signature now */
1524                         error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1525                                                 swsusp_resume_block,
1526                                                 swsusp_header, NULL);
1527                 } else {
1528                         error = -EINVAL;
1529                 }
1530
1531 put:
1532                 if (error)
1533                         blkdev_put(hib_resume_bdev, FMODE_READ);
1534                 else
1535                         pr_debug("Image signature found, resuming\n");
1536         } else {
1537                 error = PTR_ERR(hib_resume_bdev);
1538         }
1539
1540         if (error)
1541                 pr_debug("Image not found (code %d)\n", error);
1542
1543         return error;
1544 }
1545
1546 /**
1547  *      swsusp_close - close swap device.
1548  */
1549
1550 void swsusp_close(fmode_t mode)
1551 {
1552         if (IS_ERR(hib_resume_bdev)) {
1553                 pr_debug("Image device not initialised\n");
1554                 return;
1555         }
1556
1557         blkdev_put(hib_resume_bdev, mode);
1558 }
1559
1560 /**
1561  *      swsusp_unmark - Unmark swsusp signature in the resume device
1562  */
1563
1564 #ifdef CONFIG_SUSPEND
1565 int swsusp_unmark(void)
1566 {
1567         int error;
1568
1569         hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
1570                       swsusp_header, NULL);
1571         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1572                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1573                 error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1574                                         swsusp_resume_block,
1575                                         swsusp_header, NULL);
1576         } else {
1577                 pr_err("Cannot find swsusp signature!\n");
1578                 error = -ENODEV;
1579         }
1580
1581         /*
1582          * We just returned from suspend, we don't need the image any more.
1583          */
1584         free_all_swap_pages(root_swap);
1585
1586         return error;
1587 }
1588 #endif
1589
1590 static int __init swsusp_header_init(void)
1591 {
1592         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1593         if (!swsusp_header)
1594                 panic("Could not allocate memory for swsusp_header\n");
1595         return 0;
1596 }
1597
1598 core_initcall(swsusp_header_init);