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         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 339                         &hib_resume_bdev);
 340         if (res < 0)
 341                 return res;
 342
 343         root_swap = res;
 344         res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
 345         if (res)
 346                 return res;
 347
 348         res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
 349         if (res < 0)
 350                 blkdev_put(hib_resume_bdev, FMODE_WRITE);
 351
 352         /*
 353          * Update the resume device to the one actually used,
 354          * so the test_resume mode can use it in case it is
 355          * invoked from hibernate() to test the snapshot.
 356          */
 357         swsusp_resume_device = hib_resume_bdev->bd_dev;
 358         return res;
 359 }
 360
 361 /**
 362  *      write_page - Write one page to given swap location.
 363  *      @buf:           Address we're writing.
 364  *      @offset:        Offset of the swap page we're writing to.
 365  *      @hb:            bio completion batch
 366  */
 367
 368 static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 369 {
 370         void *src;
 371         int ret;
 372
 373         if (!offset)
 374                 return -ENOSPC;
 375
 376         if (hb) {
 377                 src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
 378                                               __GFP_NORETRY);
 379                 if (src) {
 380                         copy_page(src, buf);
 381                 } else {
 382                         ret = hib_wait_io(hb); /* Free pages */
 383                         if (ret)
 384                                 return ret;
 385                         src = (void *)__get_free_page(GFP_NOIO |
 386                                                       __GFP_NOWARN |
 387                                                       __GFP_NORETRY);
 388                         if (src) {
 389                                 copy_page(src, buf);
 390                         } else {
 391                                 WARN_ON_ONCE(1);
 392                                 hb = NULL;      /* Go synchronous */
 393                                 src = buf;
 394                         }
 395                 }
 396         } else {
 397                 src = buf;
 398         }
 399         return hib_submit_io(REQ_OP_WRITE, REQ_SYNC, offset, src, hb);
 400 }
 401
 402 static void release_swap_writer(struct swap_map_handle *handle)
 403 {
 404         if (handle->cur)
 405                 free_page((unsigned long)handle->cur);
 406         handle->cur = NULL;
 407 }
 408
 409 static int get_swap_writer(struct swap_map_handle *handle)
 410 {
 411         int ret;
 412
 413         ret = swsusp_swap_check();
 414         if (ret) {
 415                 if (ret != -ENOSPC)
 416                         pr_err("Cannot find swap device, try swapon -a\n");
 417                 return ret;
 418         }
 419         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 420         if (!handle->cur) {
 421                 ret = -ENOMEM;
 422                 goto err_close;
 423         }
 424         handle->cur_swap = alloc_swapdev_block(root_swap);
 425         if (!handle->cur_swap) {
 426                 ret = -ENOSPC;
 427                 goto err_rel;
 428         }
 429         handle->k = 0;
 430         handle->reqd_free_pages = reqd_free_pages();
 431         handle->first_sector = handle->cur_swap;
 432         return 0;
 433 err_rel:
 434         release_swap_writer(handle);
 435 err_close:
 436         swsusp_close(FMODE_WRITE);
 437         return ret;
 438 }
 439
 440 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 441                 struct hib_bio_batch *hb)
 442 {
 443         int error = 0;
 444         sector_t offset;
 445
 446         if (!handle->cur)
 447                 return -EINVAL;
 448         offset = alloc_swapdev_block(root_swap);
 449         error = write_page(buf, offset, hb);
 450         if (error)
 451                 return error;
 452         handle->cur->entries[handle->k++] = offset;
 453         if (handle->k >= MAP_PAGE_ENTRIES) {
 454                 offset = alloc_swapdev_block(root_swap);
 455                 if (!offset)
 456                         return -ENOSPC;
 457                 handle->cur->next_swap = offset;
 458                 error = write_page(handle->cur, handle->cur_swap, hb);
 459                 if (error)
 460                         goto out;
 461                 clear_page(handle->cur);
 462                 handle->cur_swap = offset;
 463                 handle->k = 0;
 464
 465                 if (hb && low_free_pages() <= handle->reqd_free_pages) {
 466                         error = hib_wait_io(hb);
 467                         if (error)
 468                                 goto out;
 469                         /*
 470                          * Recalculate the number of required free pages, to
 471                          * make sure we never take more than half.
 472                          */
 473                         handle->reqd_free_pages = reqd_free_pages();
 474                 }
 475         }
 476  out:
 477         return error;
 478 }
 479
 480 static int flush_swap_writer(struct swap_map_handle *handle)
 481 {
 482         if (handle->cur && handle->cur_swap)
 483                 return write_page(handle->cur, handle->cur_swap, NULL);
 484         else
 485                 return -EINVAL;
 486 }
 487
 488 static int swap_writer_finish(struct swap_map_handle *handle,
 489                 unsigned int flags, int error)
 490 {
 491         if (!error) {
 492                 flush_swap_writer(handle);
 493                 pr_info("S");
 494                 error = mark_swapfiles(handle, flags);
 495                 pr_cont("|\n");
 496         }
 497
 498         if (error)
 499                 free_all_swap_pages(root_swap);
 500         release_swap_writer(handle);
 501         swsusp_close(FMODE_WRITE);
 502
 503         return error;
 504 }
 505
 506 /* We need to remember how much compressed data we need to read. */
 507 #define LZO_HEADER      sizeof(size_t)
 508
 509 /* Number of pages/bytes we'll compress at one time. */
 510 #define LZO_UNC_PAGES   32
 511 #define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
 512
 513 /* Number of pages/bytes we need for compressed data (worst case). */
 514 #define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
 515                                      LZO_HEADER, PAGE_SIZE)
 516 #define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
 517
 518 /* Maximum number of threads for compression/decompression. */
 519 #define LZO_THREADS     3
 520
 521 /* Minimum/maximum number of pages for read buffering. */
 522 #define LZO_MIN_RD_PAGES        1024
 523 #define LZO_MAX_RD_PAGES        8192
 524
 525
 526 /**
 527  *      save_image - save the suspend image data
 528  */
 529
 530 static int save_image(struct swap_map_handle *handle,
 531                       struct snapshot_handle *snapshot,
 532                       unsigned int nr_to_write)
 533 {
 534         unsigned int m;
 535         int ret;
 536         int nr_pages;
 537         int err2;
 538         struct hib_bio_batch hb;
 539         ktime_t start;
 540         ktime_t stop;
 541
 542         hib_init_batch(&hb);
 543
 544         pr_info("Saving image data pages (%u pages)...\n",
 545                 nr_to_write);
 546         m = nr_to_write / 10;
 547         if (!m)
 548                 m = 1;
 549         nr_pages = 0;
 550         start = ktime_get();
 551         while (1) {
 552                 ret = snapshot_read_next(snapshot);
 553                 if (ret <= 0)
 554                         break;
 555                 ret = swap_write_page(handle, data_of(*snapshot), &hb);
 556                 if (ret)
 557                         break;
 558                 if (!(nr_pages % m))
 559                         pr_info("Image saving progress: %3d%%\n",
 560                                 nr_pages / m * 10);
 561                 nr_pages++;
 562         }
 563         err2 = hib_wait_io(&hb);
 564         stop = ktime_get();
 565         if (!ret)
 566                 ret = err2;
 567         if (!ret)
 568                 pr_info("Image saving done\n");
 569         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 570         return ret;
 571 }
 572
 573 /**
 574  * Structure used for CRC32.
 575  */
 576 struct crc_data {
 577         struct task_struct *thr;                  /* thread */
 578         atomic_t ready;                           /* ready to start flag */
 579         atomic_t stop;                            /* ready to stop flag */
 580         unsigned run_threads;                     /* nr current threads */
 581         wait_queue_head_t go;                     /* start crc update */
 582         wait_queue_head_t done;                   /* crc update done */
 583         u32 *crc32;                               /* points to handle's crc32 */
 584         size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
 585         unsigned char *unc[LZO_THREADS];          /* uncompressed data */
 586 };
 587
 588 /**
 589  * CRC32 update function that runs in its own thread.
 590  */
 591 static int crc32_threadfn(void *data)
 592 {
 593         struct crc_data *d = data;
 594         unsigned i;
 595
 596         while (1) {
 597                 wait_event(d->go, atomic_read(&d->ready) ||
 598                                   kthread_should_stop());
 599                 if (kthread_should_stop()) {
 600                         d->thr = NULL;
 601                         atomic_set(&d->stop, 1);
 602                         wake_up(&d->done);
 603                         break;
 604                 }
 605                 atomic_set(&d->ready, 0);
 606
 607                 for (i = 0; i < d->run_threads; i++)
 608                         *d->crc32 = crc32_le(*d->crc32,
 609                                              d->unc[i], *d->unc_len[i]);
 610                 atomic_set(&d->stop, 1);
 611                 wake_up(&d->done);
 612         }
 613         return 0;
 614 }
 615 /**
 616  * Structure used for LZO data compression.
 617  */
 618 struct cmp_data {
 619         struct task_struct *thr;                  /* thread */
 620         atomic_t ready;                           /* ready to start flag */
 621         atomic_t stop;                            /* ready to stop flag */
 622         int ret;                                  /* return code */
 623         wait_queue_head_t go;                     /* start compression */
 624         wait_queue_head_t done;                   /* compression done */
 625         size_t unc_len;                           /* uncompressed length */
 626         size_t cmp_len;                           /* compressed length */
 627         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
 628         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
 629         unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
 630 };
 631
 632 /**
 633  * Compression function that runs in its own thread.
 634  */
 635 static int lzo_compress_threadfn(void *data)
 636 {
 637         struct cmp_data *d = data;
 638
 639         while (1) {
 640                 wait_event(d->go, atomic_read(&d->ready) ||
 641                                   kthread_should_stop());
 642                 if (kthread_should_stop()) {
 643                         d->thr = NULL;
 644                         d->ret = -1;
 645                         atomic_set(&d->stop, 1);
 646                         wake_up(&d->done);
 647                         break;
 648                 }
 649                 atomic_set(&d->ready, 0);
 650
 651                 d->ret = lzo1x_1_compress(d->unc, d->unc_len,
 652                                           d->cmp + LZO_HEADER, &d->cmp_len,
 653                                           d->wrk);
 654                 atomic_set(&d->stop, 1);
 655                 wake_up(&d->done);
 656         }
 657         return 0;
 658 }
 659
 660 /**
 661  * save_image_lzo - Save the suspend image data compressed with LZO.
 662  * @handle: Swap map handle to use for saving the image.
 663  * @snapshot: Image to read data from.
 664  * @nr_to_write: Number of pages to save.
 665  */
 666 static int save_image_lzo(struct swap_map_handle *handle,
 667                           struct snapshot_handle *snapshot,
 668                           unsigned int nr_to_write)
 669 {
 670         unsigned int m;
 671         int ret = 0;
 672         int nr_pages;
 673         int err2;
 674         struct hib_bio_batch hb;
 675         ktime_t start;
 676         ktime_t stop;
 677         size_t off;
 678         unsigned thr, run_threads, nr_threads;
 679         unsigned char *page = NULL;
 680         struct cmp_data *data = NULL;
 681         struct crc_data *crc = NULL;
 682
 683         hib_init_batch(&hb);
 684
 685         /*
 686          * We'll limit the number of threads for compression to limit memory
 687          * footprint.
 688          */
 689         nr_threads = num_online_cpus() - 1;
 690         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 691
 692         page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
 693         if (!page) {
 694                 pr_err("Failed to allocate LZO page\n");
 695                 ret = -ENOMEM;
 696                 goto out_clean;
 697         }
 698
 699         data = vmalloc(array_size(nr_threads, sizeof(*data)));
 700         if (!data) {
 701                 pr_err("Failed to allocate LZO data\n");
 702                 ret = -ENOMEM;
 703                 goto out_clean;
 704         }
 705         for (thr = 0; thr < nr_threads; thr++)
 706                 memset(&data[thr], 0, offsetof(struct cmp_data, go));
 707
 708         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
 709         if (!crc) {
 710                 pr_err("Failed to allocate crc\n");
 711                 ret = -ENOMEM;
 712                 goto out_clean;
 713         }
 714         memset(crc, 0, offsetof(struct crc_data, go));
 715
 716         /*
 717          * Start the compression threads.
 718          */
 719         for (thr = 0; thr < nr_threads; thr++) {
 720                 init_waitqueue_head(&data[thr].go);
 721                 init_waitqueue_head(&data[thr].done);
 722
 723                 data[thr].thr = kthread_run(lzo_compress_threadfn,
 724                                             &data[thr],
 725                                             "image_compress/%u", thr);
 726                 if (IS_ERR(data[thr].thr)) {
 727                         data[thr].thr = NULL;
 728                         pr_err("Cannot start compression threads\n");
 729                         ret = -ENOMEM;
 730                         goto out_clean;
 731                 }
 732         }
 733
 734         /*
 735          * Start the CRC32 thread.
 736          */
 737         init_waitqueue_head(&crc->go);
 738         init_waitqueue_head(&crc->done);
 739
 740         handle->crc32 = 0;
 741         crc->crc32 = &handle->crc32;
 742         for (thr = 0; thr < nr_threads; thr++) {
 743                 crc->unc[thr] = data[thr].unc;
 744                 crc->unc_len[thr] = &data[thr].unc_len;
 745         }
 746
 747         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
 748         if (IS_ERR(crc->thr)) {
 749                 crc->thr = NULL;
 750                 pr_err("Cannot start CRC32 thread\n");
 751                 ret = -ENOMEM;
 752                 goto out_clean;
 753         }
 754
 755         /*
 756          * Adjust the number of required free pages after all allocations have
 757          * been done. We don't want to run out of pages when writing.
 758          */
 759         handle->reqd_free_pages = reqd_free_pages();
 760
 761         pr_info("Using %u thread(s) for compression\n", nr_threads);
 762         pr_info("Compressing and saving image data (%u pages)...\n",
 763                 nr_to_write);
 764         m = nr_to_write / 10;
 765         if (!m)
 766                 m = 1;
 767         nr_pages = 0;
 768         start = ktime_get();
 769         for (;;) {
 770                 for (thr = 0; thr < nr_threads; thr++) {
 771                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
 772                                 ret = snapshot_read_next(snapshot);
 773                                 if (ret < 0)
 774                                         goto out_finish;
 775
 776                                 if (!ret)
 777                                         break;
 778
 779                                 memcpy(data[thr].unc + off,
 780                                        data_of(*snapshot), PAGE_SIZE);
 781
 782                                 if (!(nr_pages % m))
 783                                         pr_info("Image saving progress: %3d%%\n",
 784                                                 nr_pages / m * 10);
 785                                 nr_pages++;
 786                         }
 787                         if (!off)
 788                                 break;
 789
 790                         data[thr].unc_len = off;
 791
 792                         atomic_set(&data[thr].ready, 1);
 793                         wake_up(&data[thr].go);
 794                 }
 795
 796                 if (!thr)
 797                         break;
 798
 799                 crc->run_threads = thr;
 800                 atomic_set(&crc->ready, 1);
 801                 wake_up(&crc->go);
 802
 803                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
 804                         wait_event(data[thr].done,
 805                                    atomic_read(&data[thr].stop));
 806                         atomic_set(&data[thr].stop, 0);
 807
 808                         ret = data[thr].ret;
 809
 810                         if (ret < 0) {
 811                                 pr_err("LZO compression failed\n");
 812                                 goto out_finish;
 813                         }
 814
 815                         if (unlikely(!data[thr].cmp_len ||
 816                                      data[thr].cmp_len >
 817                                      lzo1x_worst_compress(data[thr].unc_len))) {
 818                                 pr_err("Invalid LZO compressed length\n");
 819                                 ret = -1;
 820                                 goto out_finish;
 821                         }
 822
 823                         *(size_t *)data[thr].cmp = data[thr].cmp_len;
 824
 825                         /*
 826                          * Given we are writing one page at a time to disk, we
 827                          * copy that much from the buffer, although the last
 828                          * bit will likely be smaller than full page. This is
 829                          * OK - we saved the length of the compressed data, so
 830                          * any garbage at the end will be discarded when we
 831                          * read it.
 832                          */
 833                         for (off = 0;
 834                              off < LZO_HEADER + data[thr].cmp_len;
 835                              off += PAGE_SIZE) {
 836                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
 837
 838                                 ret = swap_write_page(handle, page, &hb);
 839                                 if (ret)
 840                                         goto out_finish;
 841                         }
 842                 }
 843
 844                 wait_event(crc->done, atomic_read(&crc->stop));
 845                 atomic_set(&crc->stop, 0);
 846         }
 847
 848 out_finish:
 849         err2 = hib_wait_io(&hb);
 850         stop = ktime_get();
 851         if (!ret)
 852                 ret = err2;
 853         if (!ret)
 854                 pr_info("Image saving done\n");
 855         swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 856 out_clean:
 857         if (crc) {
 858                 if (crc->thr)
 859                         kthread_stop(crc->thr);
 860                 kfree(crc);
 861         }
 862         if (data) {
 863                 for (thr = 0; thr < nr_threads; thr++)
 864                         if (data[thr].thr)
 865                                 kthread_stop(data[thr].thr);
 866                 vfree(data);
 867         }
 868         if (page) free_page((unsigned long)page);
 869
 870         return ret;
 871 }
 872
 873 /**
 874  *      enough_swap - Make sure we have enough swap to save the image.
 875  *
 876  *      Returns TRUE or FALSE after checking the total amount of swap
 877  *      space avaiable from the resume partition.
 878  */
 879
 880 static int enough_swap(unsigned int nr_pages)
 881 {
 882         unsigned int free_swap = count_swap_pages(root_swap, 1);
 883         unsigned int required;
 884
 885         pr_debug("Free swap pages: %u\n", free_swap);
 886
 887         required = PAGES_FOR_IO + nr_pages;
 888         return free_swap > required;
 889 }
 890
 891 /**
 892  *      swsusp_write - Write entire image and metadata.
 893  *      @flags: flags to pass to the "boot" kernel in the image header
 894  *
 895  *      It is important _NOT_ to umount filesystems at this point. We want
 896  *      them synced (in case something goes wrong) but we DO not want to mark
 897  *      filesystem clean: it is not. (And it does not matter, if we resume
 898  *      correctly, we'll mark system clean, anyway.)
 899  */
 900
 901 int swsusp_write(unsigned int flags)
 902 {
 903         struct swap_map_handle handle;
 904         struct snapshot_handle snapshot;
 905         struct swsusp_info *header;
 906         unsigned long pages;
 907         int error;
 908
 909         pages = snapshot_get_image_size();
 910         error = get_swap_writer(&handle);
 911         if (error) {
 912                 pr_err("Cannot get swap writer\n");
 913                 return error;
 914         }
 915         if (flags & SF_NOCOMPRESS_MODE) {
 916                 if (!enough_swap(pages)) {
 917                         pr_err("Not enough free swap\n");
 918                         error = -ENOSPC;
 919                         goto out_finish;
 920                 }
 921         }
 922         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 923         error = snapshot_read_next(&snapshot);
 924         if (error < (int)PAGE_SIZE) {
 925                 if (error >= 0)
 926                         error = -EFAULT;
 927
 928                 goto out_finish;
 929         }
 930         header = (struct swsusp_info *)data_of(snapshot);
 931         error = swap_write_page(&handle, header, NULL);
 932         if (!error) {
 933                 error = (flags & SF_NOCOMPRESS_MODE) ?
 934                         save_image(&handle, &snapshot, pages - 1) :
 935                         save_image_lzo(&handle, &snapshot, pages - 1);
 936         }
 937 out_finish:
 938         error = swap_writer_finish(&handle, flags, error);
 939         return error;
 940 }
 941
 942 /**
 943  *      The following functions allow us to read data using a swap map
 944  *      in a file-alike way
 945  */
 946
 947 static void release_swap_reader(struct swap_map_handle *handle)
 948 {
 949         struct swap_map_page_list *tmp;
 950
 951         while (handle->maps) {
 952                 if (handle->maps->map)
 953                         free_page((unsigned long)handle->maps->map);
 954                 tmp = handle->maps;
 955                 handle->maps = handle->maps->next;
 956                 kfree(tmp);
 957         }
 958         handle->cur = NULL;
 959 }
 960
 961 static int get_swap_reader(struct swap_map_handle *handle,
 962                 unsigned int *flags_p)
 963 {
 964         int error;
 965         struct swap_map_page_list *tmp, *last;
 966         sector_t offset;
 967
 968         *flags_p = swsusp_header->flags;
 969
 970         if (!swsusp_header->image) /* how can this happen? */
 971                 return -EINVAL;
 972
 973         handle->cur = NULL;
 974         last = handle->maps = NULL;
 975         offset = swsusp_header->image;
 976         while (offset) {
 977                 tmp = kzalloc(sizeof(*handle->maps), GFP_KERNEL);
 978                 if (!tmp) {
 979                         release_swap_reader(handle);
 980                         return -ENOMEM;
 981                 }
 982                 if (!handle->maps)
 983                         handle->maps = tmp;
 984                 if (last)
 985                         last->next = tmp;
 986                 last = tmp;
 987
 988                 tmp->map = (struct swap_map_page *)
 989                            __get_free_page(GFP_NOIO | __GFP_HIGH);
 990                 if (!tmp->map) {
 991                         release_swap_reader(handle);
 992                         return -ENOMEM;
 993                 }
 994
 995                 error = hib_submit_io(REQ_OP_READ, 0, offset, tmp->map, NULL);
 996                 if (error) {
 997                         release_swap_reader(handle);
 998                         return error;
 999                 }
1000                 offset = tmp->map->next_swap;
1001         }
1002         handle->k = 0;
1003         handle->cur = handle->maps->map;
1004         return 0;
1005 }
1006
1007 static int swap_read_page(struct swap_map_handle *handle, void *buf,
1008                 struct hib_bio_batch *hb)
1009 {
1010         sector_t offset;
1011         int error;
1012         struct swap_map_page_list *tmp;
1013
1014         if (!handle->cur)
1015                 return -EINVAL;
1016         offset = handle->cur->entries[handle->k];
1017         if (!offset)
1018                 return -EFAULT;
1019         error = hib_submit_io(REQ_OP_READ, 0, offset, buf, hb);
1020         if (error)
1021                 return error;
1022         if (++handle->k >= MAP_PAGE_ENTRIES) {
1023                 handle->k = 0;
1024                 free_page((unsigned long)handle->maps->map);
1025                 tmp = handle->maps;
1026                 handle->maps = handle->maps->next;
1027                 kfree(tmp);
1028                 if (!handle->maps)
1029                         release_swap_reader(handle);
1030                 else
1031                         handle->cur = handle->maps->map;
1032         }
1033         return error;
1034 }
1035
1036 static int swap_reader_finish(struct swap_map_handle *handle)
1037 {
1038         release_swap_reader(handle);
1039
1040         return 0;
1041 }
1042
1043 /**
1044  *      load_image - load the image using the swap map handle
1045  *      @handle and the snapshot handle @snapshot
1046  *      (assume there are @nr_pages pages to load)
1047  */
1048
1049 static int load_image(struct swap_map_handle *handle,
1050                       struct snapshot_handle *snapshot,
1051                       unsigned int nr_to_read)
1052 {
1053         unsigned int m;
1054         int ret = 0;
1055         ktime_t start;
1056         ktime_t stop;
1057         struct hib_bio_batch hb;
1058         int err2;
1059         unsigned nr_pages;
1060
1061         hib_init_batch(&hb);
1062
1063         clean_pages_on_read = true;
1064         pr_info("Loading image data pages (%u pages)...\n", nr_to_read);
1065         m = nr_to_read / 10;
1066         if (!m)
1067                 m = 1;
1068         nr_pages = 0;
1069         start = ktime_get();
1070         for ( ; ; ) {
1071                 ret = snapshot_write_next(snapshot);
1072                 if (ret <= 0)
1073                         break;
1074                 ret = swap_read_page(handle, data_of(*snapshot), &hb);
1075                 if (ret)
1076                         break;
1077                 if (snapshot->sync_read)
1078                         ret = hib_wait_io(&hb);
1079                 if (ret)
1080                         break;
1081                 if (!(nr_pages % m))
1082                         pr_info("Image loading progress: %3d%%\n",
1083                                 nr_pages / m * 10);
1084                 nr_pages++;
1085         }
1086         err2 = hib_wait_io(&hb);
1087         stop = ktime_get();
1088         if (!ret)
1089                 ret = err2;
1090         if (!ret) {
1091                 pr_info("Image loading done\n");
1092                 snapshot_write_finalize(snapshot);
1093                 if (!snapshot_image_loaded(snapshot))
1094                         ret = -ENODATA;
1095         }
1096         swsusp_show_speed(start, stop, nr_to_read, "Read");
1097         return ret;
1098 }
1099
1100 /**
1101  * Structure used for LZO data decompression.
1102  */
1103 struct dec_data {
1104         struct task_struct *thr;                  /* thread */
1105         atomic_t ready;                           /* ready to start flag */
1106         atomic_t stop;                            /* ready to stop flag */
1107         int ret;                                  /* return code */
1108         wait_queue_head_t go;                     /* start decompression */
1109         wait_queue_head_t done;                   /* decompression done */
1110         size_t unc_len;                           /* uncompressed length */
1111         size_t cmp_len;                           /* compressed length */
1112         unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
1113         unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
1114 };
1115
1116 /**
1117  * Deompression function that runs in its own thread.
1118  */
1119 static int lzo_decompress_threadfn(void *data)
1120 {
1121         struct dec_data *d = data;
1122
1123         while (1) {
1124                 wait_event(d->go, atomic_read(&d->ready) ||
1125                                   kthread_should_stop());
1126                 if (kthread_should_stop()) {
1127                         d->thr = NULL;
1128                         d->ret = -1;
1129                         atomic_set(&d->stop, 1);
1130                         wake_up(&d->done);
1131                         break;
1132                 }
1133                 atomic_set(&d->ready, 0);
1134
1135                 d->unc_len = LZO_UNC_SIZE;
1136                 d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
1137                                                d->unc, &d->unc_len);
1138                 if (clean_pages_on_decompress)
1139                         flush_icache_range((unsigned long)d->unc,
1140                                            (unsigned long)d->unc + d->unc_len);
1141
1142                 atomic_set(&d->stop, 1);
1143                 wake_up(&d->done);
1144         }
1145         return 0;
1146 }
1147
1148 /**
1149  * load_image_lzo - Load compressed image data and decompress them with LZO.
1150  * @handle: Swap map handle to use for loading data.
1151  * @snapshot: Image to copy uncompressed data into.
1152  * @nr_to_read: Number of pages to load.
1153  */
1154 static int load_image_lzo(struct swap_map_handle *handle,
1155                           struct snapshot_handle *snapshot,
1156                           unsigned int nr_to_read)
1157 {
1158         unsigned int m;
1159         int ret = 0;
1160         int eof = 0;
1161         struct hib_bio_batch hb;
1162         ktime_t start;
1163         ktime_t stop;
1164         unsigned nr_pages;
1165         size_t off;
1166         unsigned i, thr, run_threads, nr_threads;
1167         unsigned ring = 0, pg = 0, ring_size = 0,
1168                  have = 0, want, need, asked = 0;
1169         unsigned long read_pages = 0;
1170         unsigned char **page = NULL;
1171         struct dec_data *data = NULL;
1172         struct crc_data *crc = NULL;
1173
1174         hib_init_batch(&hb);
1175
1176         /*
1177          * We'll limit the number of threads for decompression to limit memory
1178          * footprint.
1179          */
1180         nr_threads = num_online_cpus() - 1;
1181         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
1182
1183         page = vmalloc(array_size(LZO_MAX_RD_PAGES, sizeof(*page)));
1184         if (!page) {
1185                 pr_err("Failed to allocate LZO page\n");
1186                 ret = -ENOMEM;
1187                 goto out_clean;
1188         }
1189
1190         data = vmalloc(array_size(nr_threads, sizeof(*data)));
1191         if (!data) {
1192                 pr_err("Failed to allocate LZO data\n");
1193                 ret = -ENOMEM;
1194                 goto out_clean;
1195         }
1196         for (thr = 0; thr < nr_threads; thr++)
1197                 memset(&data[thr], 0, offsetof(struct dec_data, go));
1198
1199         crc = kmalloc(sizeof(*crc), GFP_KERNEL);
1200         if (!crc) {
1201                 pr_err("Failed to allocate crc\n");
1202                 ret = -ENOMEM;
1203                 goto out_clean;
1204         }
1205         memset(crc, 0, offsetof(struct crc_data, go));
1206
1207         clean_pages_on_decompress = true;
1208
1209         /*
1210          * Start the decompression threads.
1211          */
1212         for (thr = 0; thr < nr_threads; thr++) {
1213                 init_waitqueue_head(&data[thr].go);
1214                 init_waitqueue_head(&data[thr].done);
1215
1216                 data[thr].thr = kthread_run(lzo_decompress_threadfn,
1217                                             &data[thr],
1218                                             "image_decompress/%u", thr);
1219                 if (IS_ERR(data[thr].thr)) {
1220                         data[thr].thr = NULL;
1221                         pr_err("Cannot start decompression threads\n");
1222                         ret = -ENOMEM;
1223                         goto out_clean;
1224                 }
1225         }
1226
1227         /*
1228          * Start the CRC32 thread.
1229          */
1230         init_waitqueue_head(&crc->go);
1231         init_waitqueue_head(&crc->done);
1232
1233         handle->crc32 = 0;
1234         crc->crc32 = &handle->crc32;
1235         for (thr = 0; thr < nr_threads; thr++) {
1236                 crc->unc[thr] = data[thr].unc;
1237                 crc->unc_len[thr] = &data[thr].unc_len;
1238         }
1239
1240         crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
1241         if (IS_ERR(crc->thr)) {
1242                 crc->thr = NULL;
1243                 pr_err("Cannot start CRC32 thread\n");
1244                 ret = -ENOMEM;
1245                 goto out_clean;
1246         }
1247
1248         /*
1249          * Set the number of pages for read buffering.
1250          * This is complete guesswork, because we'll only know the real
1251          * picture once prepare_image() is called, which is much later on
1252          * during the image load phase. We'll assume the worst case and
1253          * say that none of the image pages are from high memory.
1254          */
1255         if (low_free_pages() > snapshot_get_image_size())
1256                 read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
1257         read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
1258
1259         for (i = 0; i < read_pages; i++) {
1260                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
1261                                                   GFP_NOIO | __GFP_HIGH :
1262                                                   GFP_NOIO | __GFP_NOWARN |
1263                                                   __GFP_NORETRY);
1264
1265                 if (!page[i]) {
1266                         if (i < LZO_CMP_PAGES) {
1267                                 ring_size = i;
1268                                 pr_err("Failed to allocate LZO pages\n");
1269                                 ret = -ENOMEM;
1270                                 goto out_clean;
1271                         } else {
1272                                 break;
1273                         }
1274                 }
1275         }
1276         want = ring_size = i;
1277
1278         pr_info("Using %u thread(s) for decompression\n", nr_threads);
1279         pr_info("Loading and decompressing image data (%u pages)...\n",
1280                 nr_to_read);
1281         m = nr_to_read / 10;
1282         if (!m)
1283                 m = 1;
1284         nr_pages = 0;
1285         start = ktime_get();
1286
1287         ret = snapshot_write_next(snapshot);
1288         if (ret <= 0)
1289                 goto out_finish;
1290
1291         for(;;) {
1292                 for (i = 0; !eof && i < want; i++) {
1293                         ret = swap_read_page(handle, page[ring], &hb);
1294                         if (ret) {
1295                                 /*
1296                                  * On real read error, finish. On end of data,
1297                                  * set EOF flag and just exit the read loop.
1298                                  */
1299                                 if (handle->cur &&
1300                                     handle->cur->entries[handle->k]) {
1301                                         goto out_finish;
1302                                 } else {
1303                                         eof = 1;
1304                                         break;
1305                                 }
1306                         }
1307                         if (++ring >= ring_size)
1308                                 ring = 0;
1309                 }
1310                 asked += i;
1311                 want -= i;
1312
1313                 /*
1314                  * We are out of data, wait for some more.
1315                  */
1316                 if (!have) {
1317                         if (!asked)
1318                                 break;
1319
1320                         ret = hib_wait_io(&hb);
1321                         if (ret)
1322                                 goto out_finish;
1323                         have += asked;
1324                         asked = 0;
1325                         if (eof)
1326                                 eof = 2;
1327                 }
1328
1329                 if (crc->run_threads) {
1330                         wait_event(crc->done, atomic_read(&crc->stop));
1331                         atomic_set(&crc->stop, 0);
1332                         crc->run_threads = 0;
1333                 }
1334
1335                 for (thr = 0; have && thr < nr_threads; thr++) {
1336                         data[thr].cmp_len = *(size_t *)page[pg];
1337                         if (unlikely(!data[thr].cmp_len ||
1338                                      data[thr].cmp_len >
1339                                      lzo1x_worst_compress(LZO_UNC_SIZE))) {
1340                                 pr_err("Invalid LZO compressed length\n");
1341                                 ret = -1;
1342                                 goto out_finish;
1343                         }
1344
1345                         need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
1346                                             PAGE_SIZE);
1347                         if (need > have) {
1348                                 if (eof > 1) {
1349                                         ret = -1;
1350                                         goto out_finish;
1351                                 }
1352                                 break;
1353                         }
1354
1355                         for (off = 0;
1356                              off < LZO_HEADER + data[thr].cmp_len;
1357                              off += PAGE_SIZE) {
1358                                 memcpy(data[thr].cmp + off,
1359                                        page[pg], PAGE_SIZE);
1360                                 have--;
1361                                 want++;
1362                                 if (++pg >= ring_size)
1363                                         pg = 0;
1364                         }
1365
1366                         atomic_set(&data[thr].ready, 1);
1367                         wake_up(&data[thr].go);
1368                 }
1369
1370                 /*
1371                  * Wait for more data while we are decompressing.
1372                  */
1373                 if (have < LZO_CMP_PAGES && asked) {
1374                         ret = hib_wait_io(&hb);
1375                         if (ret)
1376                                 goto out_finish;
1377                         have += asked;
1378                         asked = 0;
1379                         if (eof)
1380                                 eof = 2;
1381                 }
1382
1383                 for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
1384                         wait_event(data[thr].done,
1385                                    atomic_read(&data[thr].stop));
1386                         atomic_set(&data[thr].stop, 0);
1387
1388                         ret = data[thr].ret;
1389
1390                         if (ret < 0) {
1391                                 pr_err("LZO decompression failed\n");
1392                                 goto out_finish;
1393                         }
1394
1395                         if (unlikely(!data[thr].unc_len ||
1396                                      data[thr].unc_len > LZO_UNC_SIZE ||
1397                                      data[thr].unc_len & (PAGE_SIZE - 1))) {
1398                                 pr_err("Invalid LZO uncompressed length\n");
1399                                 ret = -1;
1400                                 goto out_finish;
1401                         }
1402
1403                         for (off = 0;
1404                              off < data[thr].unc_len; off += PAGE_SIZE) {
1405                                 memcpy(data_of(*snapshot),
1406                                        data[thr].unc + off, PAGE_SIZE);
1407
1408                                 if (!(nr_pages % m))
1409                                         pr_info("Image loading progress: %3d%%\n",
1410                                                 nr_pages / m * 10);
1411                                 nr_pages++;
1412
1413                                 ret = snapshot_write_next(snapshot);
1414                                 if (ret <= 0) {
1415                                         crc->run_threads = thr + 1;
1416                                         atomic_set(&crc->ready, 1);
1417                                         wake_up(&crc->go);
1418                                         goto out_finish;
1419                                 }
1420                         }
1421                 }
1422
1423                 crc->run_threads = thr;
1424                 atomic_set(&crc->ready, 1);
1425                 wake_up(&crc->go);
1426         }
1427
1428 out_finish:
1429         if (crc->run_threads) {
1430                 wait_event(crc->done, atomic_read(&crc->stop));
1431                 atomic_set(&crc->stop, 0);
1432         }
1433         stop = ktime_get();
1434         if (!ret) {
1435                 pr_info("Image loading done\n");
1436                 snapshot_write_finalize(snapshot);
1437                 if (!snapshot_image_loaded(snapshot))
1438                         ret = -ENODATA;
1439                 if (!ret) {
1440                         if (swsusp_header->flags & SF_CRC32_MODE) {
1441                                 if(handle->crc32 != swsusp_header->crc32) {
1442                                         pr_err("Invalid image CRC32!\n");
1443                                         ret = -ENODATA;
1444                                 }
1445                         }
1446                 }
1447         }
1448         swsusp_show_speed(start, stop, nr_to_read, "Read");
1449 out_clean:
1450         for (i = 0; i < ring_size; i++)
1451                 free_page((unsigned long)page[i]);
1452         if (crc) {
1453                 if (crc->thr)
1454                         kthread_stop(crc->thr);
1455                 kfree(crc);
1456         }
1457         if (data) {
1458                 for (thr = 0; thr < nr_threads; thr++)
1459                         if (data[thr].thr)
1460                                 kthread_stop(data[thr].thr);
1461                 vfree(data);
1462         }
1463         vfree(page);
1464
1465         return ret;
1466 }
1467
1468 /**
1469  *      swsusp_read - read the hibernation image.
1470  *      @flags_p: flags passed by the "frozen" kernel in the image header should
1471  *                be written into this memory location
1472  */
1473
1474 int swsusp_read(unsigned int *flags_p)
1475 {
1476         int error;
1477         struct swap_map_handle handle;
1478         struct snapshot_handle snapshot;
1479         struct swsusp_info *header;
1480
1481         memset(&snapshot, 0, sizeof(struct snapshot_handle));
1482         error = snapshot_write_next(&snapshot);
1483         if (error < (int)PAGE_SIZE)
1484                 return error < 0 ? error : -EFAULT;
1485         header = (struct swsusp_info *)data_of(snapshot);
1486         error = get_swap_reader(&handle, flags_p);
1487         if (error)
1488                 goto end;
1489         if (!error)
1490                 error = swap_read_page(&handle, header, NULL);
1491         if (!error) {
1492                 error = (*flags_p & SF_NOCOMPRESS_MODE) ?
1493                         load_image(&handle, &snapshot, header->pages - 1) :
1494                         load_image_lzo(&handle, &snapshot, header->pages - 1);
1495         }
1496         swap_reader_finish(&handle);
1497 end:
1498         if (!error)
1499                 pr_debug("Image successfully loaded\n");
1500         else
1501                 pr_debug("Error %d resuming\n", error);
1502         return error;
1503 }
1504
1505 /**
1506  *      swsusp_check - Check for swsusp signature in the resume device
1507  */
1508
1509 int swsusp_check(void)
1510 {
1511         int error;
1512
1513         hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
1514                                             FMODE_READ, NULL);
1515         if (!IS_ERR(hib_resume_bdev)) {
1516                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
1517                 clear_page(swsusp_header);
1518                 error = hib_submit_io(REQ_OP_READ, 0,
1519                                         swsusp_resume_block,
1520                                         swsusp_header, NULL);
1521                 if (error)
1522                         goto put;
1523
1524                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
1525                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
1526                         /* Reset swap signature now */
1527                         error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1528                                                 swsusp_resume_block,
1529                                                 swsusp_header, NULL);
1530                 } else {
1531                         error = -EINVAL;
1532                 }
1533
1534 put:
1535                 if (error)
1536                         blkdev_put(hib_resume_bdev, FMODE_READ);
1537                 else
1538                         pr_debug("Image signature found, resuming\n");
1539         } else {
1540                 error = PTR_ERR(hib_resume_bdev);
1541         }
1542
1543         if (error)
1544                 pr_debug("Image not found (code %d)\n", error);
1545
1546         return error;
1547 }
1548
1549 /**
1550  *      swsusp_close - close swap device.
1551  */
1552
1553 void swsusp_close(fmode_t mode)
1554 {
1555         if (IS_ERR(hib_resume_bdev)) {
1556                 pr_debug("Image device not initialised\n");
1557                 return;
1558         }
1559
1560         blkdev_put(hib_resume_bdev, mode);
1561 }
1562
1563 /**
1564  *      swsusp_unmark - Unmark swsusp signature in the resume device
1565  */
1566
1567 #ifdef CONFIG_SUSPEND
1568 int swsusp_unmark(void)
1569 {
1570         int error;
1571
1572         hib_submit_io(REQ_OP_READ, 0, swsusp_resume_block,
1573                       swsusp_header, NULL);
1574         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
1575                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
1576                 error = hib_submit_io(REQ_OP_WRITE, REQ_SYNC,
1577                                         swsusp_resume_block,
1578                                         swsusp_header, NULL);
1579         } else {
1580                 pr_err("Cannot find swsusp signature!\n");
1581                 error = -ENODEV;
1582         }
1583
1584         /*
1585          * We just returned from suspend, we don't need the image any more.
1586          */
1587         free_all_swap_pages(root_swap);
1588
1589         return error;
1590 }
1591 #endif
1592
1593 static int swsusp_header_init(void)
1594 {
1595         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
1596         if (!swsusp_header)
1597                 panic("Could not allocate memory for swsusp_header\n");
1598         return 0;
1599 }
1600
1601 core_initcall(swsusp_header_init);