kernel/power/swap.c

   1 /*
   2  * linux/kernel/power/swap.c
   3  *
   4  * This file provides functions for reading the suspend image from
   5  * and writing it to a swap partition.
   6  *
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
   9  *
  10  * This file is released under the GPLv2.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/file.h>
  17 #include <linux/utsname.h>
  18 #include <linux/version.h>
  19 #include <linux/delay.h>
  20 #include <linux/bitops.h>
  21 #include <linux/genhd.h>
  22 #include <linux/device.h>
  23 #include <linux/buffer_head.h>
  24 #include <linux/bio.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/swap.h>
  27 #include <linux/swapops.h>
  28 #include <linux/pm.h>
  29
  30 #include "power.h"
  31
  32 extern char resume_file[];
  33
  34 #define SWSUSP_SIG      "S1SUSPEND"
  35
  36 static struct swsusp_header {
  37         char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
  38         sector_t image;
  39         char    orig_sig[10];
  40         char    sig[10];
  41 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
  42
  43 /*
  44  * General things
  45  */
  46
  47 static unsigned short root_swap = 0xffff;
  48 static struct block_device *resume_bdev;
  49
  50 /**
  51  *      submit - submit BIO request.
  52  *      @rw:    READ or WRITE.
  53  *      @off    physical offset of page.
  54  *      @page:  page we're reading or writing.
  55  *      @bio_chain: list of pending biod (for async reading)
  56  *
  57  *      Straight from the textbook - allocate and initialize the bio.
  58  *      If we're reading, make sure the page is marked as dirty.
  59  *      Then submit it and, if @bio_chain == NULL, wait.
  60  */
  61 static int submit(int rw, pgoff_t page_off, struct page *page,
  62                         struct bio **bio_chain)
  63 {
  64         struct bio *bio;
  65
  66         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  67         if (!bio)
  68                 return -ENOMEM;
  69         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  70         bio->bi_bdev = resume_bdev;
  71         bio->bi_end_io = end_swap_bio_read;
  72
  73         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  74                 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
  75                 bio_put(bio);
  76                 return -EFAULT;
  77         }
  78
  79         lock_page(page);
  80         bio_get(bio);
  81
  82         if (bio_chain == NULL) {
  83                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  84                 wait_on_page_locked(page);
  85                 if (rw == READ)
  86                         bio_set_pages_dirty(bio);
  87                 bio_put(bio);
  88         } else {
  89                 if (rw == READ)
  90                         get_page(page); /* These pages are freed later */
  91                 bio->bi_private = *bio_chain;
  92                 *bio_chain = bio;
  93                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  94         }
  95         return 0;
  96 }
  97
  98 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
  99 {
 100         return submit(READ, page_off, virt_to_page(addr), bio_chain);
 101 }
 102
 103 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 104 {
 105         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
 106 }
 107
 108 static int wait_on_bio_chain(struct bio **bio_chain)
 109 {
 110         struct bio *bio;
 111         struct bio *next_bio;
 112         int ret = 0;
 113
 114         if (bio_chain == NULL)
 115                 return 0;
 116
 117         bio = *bio_chain;
 118         if (bio == NULL)
 119                 return 0;
 120         while (bio) {
 121                 struct page *page;
 122
 123                 next_bio = bio->bi_private;
 124                 page = bio->bi_io_vec[0].bv_page;
 125                 wait_on_page_locked(page);
 126                 if (!PageUptodate(page) || PageError(page))
 127                         ret = -EIO;
 128                 put_page(page);
 129                 bio_put(bio);
 130                 bio = next_bio;
 131         }
 132         *bio_chain = NULL;
 133         return ret;
 134 }
 135
 136 /*
 137  * Saving part
 138  */
 139
 140 static int mark_swapfiles(sector_t start)
 141 {
 142         int error;
 143
 144         bio_read_page(swsusp_resume_block, &swsusp_header, NULL);
 145         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
 146             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
 147                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 148                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 149                 swsusp_header.image = start;
 150                 error = bio_write_page(swsusp_resume_block,
 151                                         &swsusp_header, NULL);
 152         } else {
 153                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 154                 error = -ENODEV;
 155         }
 156         return error;
 157 }
 158
 159 /**
 160  *      swsusp_swap_check - check if the resume device is a swap device
 161  *      and get its index (if so)
 162  */
 163
 164 static int swsusp_swap_check(void) /* This is called before saving image */
 165 {
 166         int res;
 167
 168         res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
 169         if (res < 0)
 170                 return res;
 171
 172         root_swap = res;
 173         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_WRITE);
 174         if (IS_ERR(resume_bdev))
 175                 return PTR_ERR(resume_bdev);
 176
 177         res = set_blocksize(resume_bdev, PAGE_SIZE);
 178         if (res < 0)
 179                 blkdev_put(resume_bdev);
 180
 181         return res;
 182 }
 183
 184 /**
 185  *      write_page - Write one page to given swap location.
 186  *      @buf:           Address we're writing.
 187  *      @offset:        Offset of the swap page we're writing to.
 188  *      @bio_chain:     Link the next write BIO here
 189  */
 190
 191 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 192 {
 193         void *src;
 194
 195         if (!offset)
 196                 return -ENOSPC;
 197
 198         if (bio_chain) {
 199                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 200                 if (src) {
 201                         memcpy(src, buf, PAGE_SIZE);
 202                 } else {
 203                         WARN_ON_ONCE(1);
 204                         bio_chain = NULL;       /* Go synchronous */
 205                         src = buf;
 206                 }
 207         } else {
 208                 src = buf;
 209         }
 210         return bio_write_page(offset, src, bio_chain);
 211 }
 212
 213 /*
 214  *      The swap map is a data structure used for keeping track of each page
 215  *      written to a swap partition.  It consists of many swap_map_page
 216  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 217  *      These structures are stored on the swap and linked together with the
 218  *      help of the .next_swap member.
 219  *
 220  *      The swap map is created during suspend.  The swap map pages are
 221  *      allocated and populated one at a time, so we only need one memory
 222  *      page to set up the entire structure.
 223  *
 224  *      During resume we also only need to use one swap_map_page structure
 225  *      at a time.
 226  */
 227
 228 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 229
 230 struct swap_map_page {
 231         sector_t entries[MAP_PAGE_ENTRIES];
 232         sector_t next_swap;
 233 };
 234
 235 /**
 236  *      The swap_map_handle structure is used for handling swap in
 237  *      a file-alike way
 238  */
 239
 240 struct swap_map_handle {
 241         struct swap_map_page *cur;
 242         sector_t cur_swap;
 243         struct bitmap_page *bitmap;
 244         unsigned int k;
 245 };
 246
 247 static void release_swap_writer(struct swap_map_handle *handle)
 248 {
 249         if (handle->cur)
 250                 free_page((unsigned long)handle->cur);
 251         handle->cur = NULL;
 252         if (handle->bitmap)
 253                 free_bitmap(handle->bitmap);
 254         handle->bitmap = NULL;
 255 }
 256
 257 static int get_swap_writer(struct swap_map_handle *handle)
 258 {
 259         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 260         if (!handle->cur)
 261                 return -ENOMEM;
 262         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 263         if (!handle->bitmap) {
 264                 release_swap_writer(handle);
 265                 return -ENOMEM;
 266         }
 267         handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
 268         if (!handle->cur_swap) {
 269                 release_swap_writer(handle);
 270                 return -ENOSPC;
 271         }
 272         handle->k = 0;
 273         return 0;
 274 }
 275
 276 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 277                                 struct bio **bio_chain)
 278 {
 279         int error = 0;
 280         sector_t offset;
 281
 282         if (!handle->cur)
 283                 return -EINVAL;
 284         offset = alloc_swapdev_block(root_swap, handle->bitmap);
 285         error = write_page(buf, offset, bio_chain);
 286         if (error)
 287                 return error;
 288         handle->cur->entries[handle->k++] = offset;
 289         if (handle->k >= MAP_PAGE_ENTRIES) {
 290                 error = wait_on_bio_chain(bio_chain);
 291                 if (error)
 292                         goto out;
 293                 offset = alloc_swapdev_block(root_swap, handle->bitmap);
 294                 if (!offset)
 295                         return -ENOSPC;
 296                 handle->cur->next_swap = offset;
 297                 error = write_page(handle->cur, handle->cur_swap, NULL);
 298                 if (error)
 299                         goto out;
 300                 memset(handle->cur, 0, PAGE_SIZE);
 301                 handle->cur_swap = offset;
 302                 handle->k = 0;
 303         }
 304  out:
 305         return error;
 306 }
 307
 308 static int flush_swap_writer(struct swap_map_handle *handle)
 309 {
 310         if (handle->cur && handle->cur_swap)
 311                 return write_page(handle->cur, handle->cur_swap, NULL);
 312         else
 313                 return -EINVAL;
 314 }
 315
 316 /**
 317  *      save_image - save the suspend image data
 318  */
 319
 320 static int save_image(struct swap_map_handle *handle,
 321                       struct snapshot_handle *snapshot,
 322                       unsigned int nr_to_write)
 323 {
 324         unsigned int m;
 325         int ret;
 326         int error = 0;
 327         int nr_pages;
 328         int err2;
 329         struct bio *bio;
 330         struct timeval start;
 331         struct timeval stop;
 332
 333         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 334         m = nr_to_write / 100;
 335         if (!m)
 336                 m = 1;
 337         nr_pages = 0;
 338         bio = NULL;
 339         do_gettimeofday(&start);
 340         do {
 341                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 342                 if (ret > 0) {
 343                         error = swap_write_page(handle, data_of(*snapshot),
 344                                                 &bio);
 345                         if (error)
 346                                 break;
 347                         if (!(nr_pages % m))
 348                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 349                         nr_pages++;
 350                 }
 351         } while (ret > 0);
 352         err2 = wait_on_bio_chain(&bio);
 353         do_gettimeofday(&stop);
 354         if (!error)
 355                 error = err2;
 356         if (!error)
 357                 printk("\b\b\b\bdone\n");
 358         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 359         return error;
 360 }
 361
 362 /**
 363  *      enough_swap - Make sure we have enough swap to save the image.
 364  *
 365  *      Returns TRUE or FALSE after checking the total amount of swap
 366  *      space avaiable from the resume partition.
 367  */
 368
 369 static int enough_swap(unsigned int nr_pages)
 370 {
 371         unsigned int free_swap = count_swap_pages(root_swap, 1);
 372
 373         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 374         return free_swap > nr_pages + PAGES_FOR_IO;
 375 }
 376
 377 /**
 378  *      swsusp_write - Write entire image and metadata.
 379  *
 380  *      It is important _NOT_ to umount filesystems at this point. We want
 381  *      them synced (in case something goes wrong) but we DO not want to mark
 382  *      filesystem clean: it is not. (And it does not matter, if we resume
 383  *      correctly, we'll mark system clean, anyway.)
 384  */
 385
 386 int swsusp_write(void)
 387 {
 388         struct swap_map_handle handle;
 389         struct snapshot_handle snapshot;
 390         struct swsusp_info *header;
 391         int error;
 392
 393         error = swsusp_swap_check();
 394         if (error) {
 395                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 396                                 "swapon -a.\n");
 397                 return error;
 398         }
 399         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 400         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 401         if (error < PAGE_SIZE) {
 402                 if (error >= 0)
 403                         error = -EFAULT;
 404
 405                 goto out;
 406         }
 407         header = (struct swsusp_info *)data_of(snapshot);
 408         if (!enough_swap(header->pages)) {
 409                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 410                 error = -ENOSPC;
 411                 goto out;
 412         }
 413         error = get_swap_writer(&handle);
 414         if (!error) {
 415                 sector_t start = handle.cur_swap;
 416
 417                 error = swap_write_page(&handle, header, NULL);
 418                 if (!error)
 419                         error = save_image(&handle, &snapshot,
 420                                         header->pages - 1);
 421
 422                 if (!error) {
 423                         flush_swap_writer(&handle);
 424                         printk("S");
 425                         error = mark_swapfiles(start);
 426                         printk("|\n");
 427                 }
 428         }
 429         if (error)
 430                 free_all_swap_pages(root_swap, handle.bitmap);
 431         release_swap_writer(&handle);
 432  out:
 433         swsusp_close();
 434         return error;
 435 }
 436
 437 /**
 438  *      The following functions allow us to read data using a swap map
 439  *      in a file-alike way
 440  */
 441
 442 static void release_swap_reader(struct swap_map_handle *handle)
 443 {
 444         if (handle->cur)
 445                 free_page((unsigned long)handle->cur);
 446         handle->cur = NULL;
 447 }
 448
 449 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 450 {
 451         int error;
 452
 453         if (!start)
 454                 return -EINVAL;
 455
 456         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 457         if (!handle->cur)
 458                 return -ENOMEM;
 459
 460         error = bio_read_page(start, handle->cur, NULL);
 461         if (error) {
 462                 release_swap_reader(handle);
 463                 return error;
 464         }
 465         handle->k = 0;
 466         return 0;
 467 }
 468
 469 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 470                                 struct bio **bio_chain)
 471 {
 472         sector_t offset;
 473         int error;
 474
 475         if (!handle->cur)
 476                 return -EINVAL;
 477         offset = handle->cur->entries[handle->k];
 478         if (!offset)
 479                 return -EFAULT;
 480         error = bio_read_page(offset, buf, bio_chain);
 481         if (error)
 482                 return error;
 483         if (++handle->k >= MAP_PAGE_ENTRIES) {
 484                 error = wait_on_bio_chain(bio_chain);
 485                 handle->k = 0;
 486                 offset = handle->cur->next_swap;
 487                 if (!offset)
 488                         release_swap_reader(handle);
 489                 else if (!error)
 490                         error = bio_read_page(offset, handle->cur, NULL);
 491         }
 492         return error;
 493 }
 494
 495 /**
 496  *      load_image - load the image using the swap map handle
 497  *      @handle and the snapshot handle @snapshot
 498  *      (assume there are @nr_pages pages to load)
 499  */
 500
 501 static int load_image(struct swap_map_handle *handle,
 502                       struct snapshot_handle *snapshot,
 503                       unsigned int nr_to_read)
 504 {
 505         unsigned int m;
 506         int error = 0;
 507         struct timeval start;
 508         struct timeval stop;
 509         struct bio *bio;
 510         int err2;
 511         unsigned nr_pages;
 512
 513         printk("Loading image data pages (%u pages) ...     ", nr_to_read);
 514         m = nr_to_read / 100;
 515         if (!m)
 516                 m = 1;
 517         nr_pages = 0;
 518         bio = NULL;
 519         do_gettimeofday(&start);
 520         for ( ; ; ) {
 521                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 522                 if (error <= 0)
 523                         break;
 524                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 525                 if (error)
 526                         break;
 527                 if (snapshot->sync_read)
 528                         error = wait_on_bio_chain(&bio);
 529                 if (error)
 530                         break;
 531                 if (!(nr_pages % m))
 532                         printk("\b\b\b\b%3d%%", nr_pages / m);
 533                 nr_pages++;
 534         }
 535         err2 = wait_on_bio_chain(&bio);
 536         do_gettimeofday(&stop);
 537         if (!error)
 538                 error = err2;
 539         if (!error) {
 540                 printk("\b\b\b\bdone\n");
 541                 snapshot_write_finalize(snapshot);
 542                 if (!snapshot_image_loaded(snapshot))
 543                         error = -ENODATA;
 544         }
 545         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 546         return error;
 547 }
 548
 549 int swsusp_read(void)
 550 {
 551         int error;
 552         struct swap_map_handle handle;
 553         struct snapshot_handle snapshot;
 554         struct swsusp_info *header;
 555
 556         if (IS_ERR(resume_bdev)) {
 557                 pr_debug("swsusp: block device not initialised\n");
 558                 return PTR_ERR(resume_bdev);
 559         }
 560
 561         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 562         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 563         if (error < PAGE_SIZE)
 564                 return error < 0 ? error : -EFAULT;
 565         header = (struct swsusp_info *)data_of(snapshot);
 566         error = get_swap_reader(&handle, swsusp_header.image);
 567         if (!error)
 568                 error = swap_read_page(&handle, header, NULL);
 569         if (!error)
 570                 error = load_image(&handle, &snapshot, header->pages - 1);
 571         release_swap_reader(&handle);
 572
 573         blkdev_put(resume_bdev);
 574
 575         if (!error)
 576                 pr_debug("swsusp: Reading resume file was successful\n");
 577         else
 578                 pr_debug("swsusp: Error %d resuming\n", error);
 579         return error;
 580 }
 581
 582 /**
 583  *      swsusp_check - Check for swsusp signature in the resume device
 584  */
 585
 586 int swsusp_check(void)
 587 {
 588         int error;
 589
 590         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 591         if (!IS_ERR(resume_bdev)) {
 592                 set_blocksize(resume_bdev, PAGE_SIZE);
 593                 memset(&swsusp_header, 0, sizeof(swsusp_header));
 594                 error = bio_read_page(swsusp_resume_block,
 595                                         &swsusp_header, NULL);
 596                 if (error)
 597                         return error;
 598
 599                 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 600                         memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 601                         /* Reset swap signature now */
 602                         error = bio_write_page(swsusp_resume_block,
 603                                                 &swsusp_header, NULL);
 604                 } else {
 605                         return -EINVAL;
 606                 }
 607                 if (error)
 608                         blkdev_put(resume_bdev);
 609                 else
 610                         pr_debug("swsusp: Signature found, resuming\n");
 611         } else {
 612                 error = PTR_ERR(resume_bdev);
 613         }
 614
 615         if (error)
 616                 pr_debug("swsusp: Error %d check for resume file\n", error);
 617
 618         return error;
 619 }
 620
 621 /**
 622  *      swsusp_close - close swap device.
 623  */
 624
 625 void swsusp_close(void)
 626 {
 627         if (IS_ERR(resume_bdev)) {
 628                 pr_debug("swsusp: block device not initialised\n");
 629                 return;
 630         }
 631
 632         blkdev_put(resume_bdev);
 633 }