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/file.h>
  16 #include <linux/utsname.h>
  17 #include <linux/delay.h>
  18 #include <linux/bitops.h>
  19 #include <linux/genhd.h>
  20 #include <linux/device.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/bio.h>
  23 #include <linux/blkdev.h>
  24 #include <linux/swap.h>
  25 #include <linux/swapops.h>
  26 #include <linux/pm.h>
  27
  28 #include "power.h"
  29
  30 #define SWSUSP_SIG      "S1SUSPEND"
  31
  32 struct swsusp_header {
  33         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
  34         sector_t image;
  35         unsigned int flags;     /* Flags to pass to the "boot" kernel */
  36         char    orig_sig[10];
  37         char    sig[10];
  38 } __attribute__((packed));
  39
  40 static struct swsusp_header *swsusp_header;
  41
  42 /*
  43  * General things
  44  */
  45
  46 static unsigned short root_swap = 0xffff;
  47 static struct block_device *resume_bdev;
  48
  49 /**
  50  *      submit - submit BIO request.
  51  *      @rw:    READ or WRITE.
  52  *      @off    physical offset of page.
  53  *      @page:  page we're reading or writing.
  54  *      @bio_chain: list of pending biod (for async reading)
  55  *
  56  *      Straight from the textbook - allocate and initialize the bio.
  57  *      If we're reading, make sure the page is marked as dirty.
  58  *      Then submit it and, if @bio_chain == NULL, wait.
  59  */
  60 static int submit(int rw, pgoff_t page_off, struct page *page,
  61                         struct bio **bio_chain)
  62 {
  63         const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
  64         struct bio *bio;
  65
  66         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  67         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  68         bio->bi_bdev = resume_bdev;
  69         bio->bi_end_io = end_swap_bio_read;
  70
  71         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  72                 printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
  73                         page_off);
  74                 bio_put(bio);
  75                 return -EFAULT;
  76         }
  77
  78         lock_page(page);
  79         bio_get(bio);
  80
  81         if (bio_chain == NULL) {
  82                 submit_bio(bio_rw, bio);
  83                 wait_on_page_locked(page);
  84                 if (rw == READ)
  85                         bio_set_pages_dirty(bio);
  86                 bio_put(bio);
  87         } else {
  88                 if (rw == READ)
  89                         get_page(page); /* These pages are freed later */
  90                 bio->bi_private = *bio_chain;
  91                 *bio_chain = bio;
  92                 submit_bio(bio_rw, bio);
  93         }
  94         return 0;
  95 }
  96
  97 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
  98 {
  99         return submit(READ, page_off, virt_to_page(addr), bio_chain);
 100 }
 101
 102 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 103 {
 104         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
 105 }
 106
 107 static int wait_on_bio_chain(struct bio **bio_chain)
 108 {
 109         struct bio *bio;
 110         struct bio *next_bio;
 111         int ret = 0;
 112
 113         if (bio_chain == NULL)
 114                 return 0;
 115
 116         bio = *bio_chain;
 117         if (bio == NULL)
 118                 return 0;
 119         while (bio) {
 120                 struct page *page;
 121
 122                 next_bio = bio->bi_private;
 123                 page = bio->bi_io_vec[0].bv_page;
 124                 wait_on_page_locked(page);
 125                 if (!PageUptodate(page) || PageError(page))
 126                         ret = -EIO;
 127                 put_page(page);
 128                 bio_put(bio);
 129                 bio = next_bio;
 130         }
 131         *bio_chain = NULL;
 132         return ret;
 133 }
 134
 135 /*
 136  * Saving part
 137  */
 138
 139 static int mark_swapfiles(sector_t start, unsigned int flags)
 140 {
 141         int error;
 142
 143         bio_read_page(swsusp_resume_block, swsusp_header, NULL);
 144         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 145             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 146                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 147                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
 148                 swsusp_header->image = start;
 149                 swsusp_header->flags = flags;
 150                 error = bio_write_page(swsusp_resume_block,
 151                                         swsusp_header, NULL);
 152         } else {
 153                 printk(KERN_ERR "PM: 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                         &resume_bdev);
 170         if (res < 0)
 171                 return res;
 172
 173         root_swap = res;
 174         res = blkdev_get(resume_bdev, FMODE_WRITE);
 175         if (res)
 176                 return res;
 177
 178         res = set_blocksize(resume_bdev, PAGE_SIZE);
 179         if (res < 0)
 180                 blkdev_put(resume_bdev, FMODE_WRITE);
 181
 182         return res;
 183 }
 184
 185 /**
 186  *      write_page - Write one page to given swap location.
 187  *      @buf:           Address we're writing.
 188  *      @offset:        Offset of the swap page we're writing to.
 189  *      @bio_chain:     Link the next write BIO here
 190  */
 191
 192 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 193 {
 194         void *src;
 195
 196         if (!offset)
 197                 return -ENOSPC;
 198
 199         if (bio_chain) {
 200                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 201                 if (src) {
 202                         memcpy(src, buf, PAGE_SIZE);
 203                 } else {
 204                         WARN_ON_ONCE(1);
 205                         bio_chain = NULL;       /* Go synchronous */
 206                         src = buf;
 207                 }
 208         } else {
 209                 src = buf;
 210         }
 211         return bio_write_page(offset, src, bio_chain);
 212 }
 213
 214 /*
 215  *      The swap map is a data structure used for keeping track of each page
 216  *      written to a swap partition.  It consists of many swap_map_page
 217  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 218  *      These structures are stored on the swap and linked together with the
 219  *      help of the .next_swap member.
 220  *
 221  *      The swap map is created during suspend.  The swap map pages are
 222  *      allocated and populated one at a time, so we only need one memory
 223  *      page to set up the entire structure.
 224  *
 225  *      During resume we also only need to use one swap_map_page structure
 226  *      at a time.
 227  */
 228
 229 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 230
 231 struct swap_map_page {
 232         sector_t entries[MAP_PAGE_ENTRIES];
 233         sector_t next_swap;
 234 };
 235
 236 /**
 237  *      The swap_map_handle structure is used for handling swap in
 238  *      a file-alike way
 239  */
 240
 241 struct swap_map_handle {
 242         struct swap_map_page *cur;
 243         sector_t cur_swap;
 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 }
 253
 254 static int get_swap_writer(struct swap_map_handle *handle)
 255 {
 256         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 257         if (!handle->cur)
 258                 return -ENOMEM;
 259         handle->cur_swap = alloc_swapdev_block(root_swap);
 260         if (!handle->cur_swap) {
 261                 release_swap_writer(handle);
 262                 return -ENOSPC;
 263         }
 264         handle->k = 0;
 265         return 0;
 266 }
 267
 268 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 269                                 struct bio **bio_chain)
 270 {
 271         int error = 0;
 272         sector_t offset;
 273
 274         if (!handle->cur)
 275                 return -EINVAL;
 276         offset = alloc_swapdev_block(root_swap);
 277         error = write_page(buf, offset, bio_chain);
 278         if (error)
 279                 return error;
 280         handle->cur->entries[handle->k++] = offset;
 281         if (handle->k >= MAP_PAGE_ENTRIES) {
 282                 error = wait_on_bio_chain(bio_chain);
 283                 if (error)
 284                         goto out;
 285                 offset = alloc_swapdev_block(root_swap);
 286                 if (!offset)
 287                         return -ENOSPC;
 288                 handle->cur->next_swap = offset;
 289                 error = write_page(handle->cur, handle->cur_swap, NULL);
 290                 if (error)
 291                         goto out;
 292                 memset(handle->cur, 0, PAGE_SIZE);
 293                 handle->cur_swap = offset;
 294                 handle->k = 0;
 295         }
 296  out:
 297         return error;
 298 }
 299
 300 static int flush_swap_writer(struct swap_map_handle *handle)
 301 {
 302         if (handle->cur && handle->cur_swap)
 303                 return write_page(handle->cur, handle->cur_swap, NULL);
 304         else
 305                 return -EINVAL;
 306 }
 307
 308 /**
 309  *      save_image - save the suspend image data
 310  */
 311
 312 static int save_image(struct swap_map_handle *handle,
 313                       struct snapshot_handle *snapshot,
 314                       unsigned int nr_to_write)
 315 {
 316         unsigned int m;
 317         int ret;
 318         int error = 0;
 319         int nr_pages;
 320         int err2;
 321         struct bio *bio;
 322         struct timeval start;
 323         struct timeval stop;
 324
 325         printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
 326                 nr_to_write);
 327         m = nr_to_write / 100;
 328         if (!m)
 329                 m = 1;
 330         nr_pages = 0;
 331         bio = NULL;
 332         do_gettimeofday(&start);
 333         do {
 334                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 335                 if (ret > 0) {
 336                         error = swap_write_page(handle, data_of(*snapshot),
 337                                                 &bio);
 338                         if (error)
 339                                 break;
 340                         if (!(nr_pages % m))
 341                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 342                         nr_pages++;
 343                 }
 344         } while (ret > 0);
 345         err2 = wait_on_bio_chain(&bio);
 346         do_gettimeofday(&stop);
 347         if (!error)
 348                 error = err2;
 349         if (!error)
 350                 printk("\b\b\b\bdone\n");
 351         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 352         return error;
 353 }
 354
 355 /**
 356  *      enough_swap - Make sure we have enough swap to save the image.
 357  *
 358  *      Returns TRUE or FALSE after checking the total amount of swap
 359  *      space avaiable from the resume partition.
 360  */
 361
 362 static int enough_swap(unsigned int nr_pages)
 363 {
 364         unsigned int free_swap = count_swap_pages(root_swap, 1);
 365
 366         pr_debug("PM: Free swap pages: %u\n", free_swap);
 367         return free_swap > nr_pages + PAGES_FOR_IO;
 368 }
 369
 370 /**
 371  *      swsusp_write - Write entire image and metadata.
 372  *      @flags: flags to pass to the "boot" kernel in the image header
 373  *
 374  *      It is important _NOT_ to umount filesystems at this point. We want
 375  *      them synced (in case something goes wrong) but we DO not want to mark
 376  *      filesystem clean: it is not. (And it does not matter, if we resume
 377  *      correctly, we'll mark system clean, anyway.)
 378  */
 379
 380 int swsusp_write(unsigned int flags)
 381 {
 382         struct swap_map_handle handle;
 383         struct snapshot_handle snapshot;
 384         struct swsusp_info *header;
 385         int error;
 386
 387         error = swsusp_swap_check();
 388         if (error) {
 389                 printk(KERN_ERR "PM: Cannot find swap device, try "
 390                                 "swapon -a.\n");
 391                 return error;
 392         }
 393         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 394         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 395         if (error < PAGE_SIZE) {
 396                 if (error >= 0)
 397                         error = -EFAULT;
 398
 399                 goto out;
 400         }
 401         header = (struct swsusp_info *)data_of(snapshot);
 402         if (!enough_swap(header->pages)) {
 403                 printk(KERN_ERR "PM: Not enough free swap\n");
 404                 error = -ENOSPC;
 405                 goto out;
 406         }
 407         error = get_swap_writer(&handle);
 408         if (!error) {
 409                 sector_t start = handle.cur_swap;
 410
 411                 error = swap_write_page(&handle, header, NULL);
 412                 if (!error)
 413                         error = save_image(&handle, &snapshot,
 414                                         header->pages - 1);
 415
 416                 if (!error) {
 417                         flush_swap_writer(&handle);
 418                         printk(KERN_INFO "PM: S");
 419                         error = mark_swapfiles(start, flags);
 420                         printk("|\n");
 421                 }
 422         }
 423         if (error)
 424                 free_all_swap_pages(root_swap);
 425
 426         release_swap_writer(&handle);
 427  out:
 428         swsusp_close(FMODE_WRITE);
 429         return error;
 430 }
 431
 432 /**
 433  *      The following functions allow us to read data using a swap map
 434  *      in a file-alike way
 435  */
 436
 437 static void release_swap_reader(struct swap_map_handle *handle)
 438 {
 439         if (handle->cur)
 440                 free_page((unsigned long)handle->cur);
 441         handle->cur = NULL;
 442 }
 443
 444 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 445 {
 446         int error;
 447
 448         if (!start)
 449                 return -EINVAL;
 450
 451         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 452         if (!handle->cur)
 453                 return -ENOMEM;
 454
 455         error = bio_read_page(start, handle->cur, NULL);
 456         if (error) {
 457                 release_swap_reader(handle);
 458                 return error;
 459         }
 460         handle->k = 0;
 461         return 0;
 462 }
 463
 464 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 465                                 struct bio **bio_chain)
 466 {
 467         sector_t offset;
 468         int error;
 469
 470         if (!handle->cur)
 471                 return -EINVAL;
 472         offset = handle->cur->entries[handle->k];
 473         if (!offset)
 474                 return -EFAULT;
 475         error = bio_read_page(offset, buf, bio_chain);
 476         if (error)
 477                 return error;
 478         if (++handle->k >= MAP_PAGE_ENTRIES) {
 479                 error = wait_on_bio_chain(bio_chain);
 480                 handle->k = 0;
 481                 offset = handle->cur->next_swap;
 482                 if (!offset)
 483                         release_swap_reader(handle);
 484                 else if (!error)
 485                         error = bio_read_page(offset, handle->cur, NULL);
 486         }
 487         return error;
 488 }
 489
 490 /**
 491  *      load_image - load the image using the swap map handle
 492  *      @handle and the snapshot handle @snapshot
 493  *      (assume there are @nr_pages pages to load)
 494  */
 495
 496 static int load_image(struct swap_map_handle *handle,
 497                       struct snapshot_handle *snapshot,
 498                       unsigned int nr_to_read)
 499 {
 500         unsigned int m;
 501         int error = 0;
 502         struct timeval start;
 503         struct timeval stop;
 504         struct bio *bio;
 505         int err2;
 506         unsigned nr_pages;
 507
 508         printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
 509                 nr_to_read);
 510         m = nr_to_read / 100;
 511         if (!m)
 512                 m = 1;
 513         nr_pages = 0;
 514         bio = NULL;
 515         do_gettimeofday(&start);
 516         for ( ; ; ) {
 517                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 518                 if (error <= 0)
 519                         break;
 520                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 521                 if (error)
 522                         break;
 523                 if (snapshot->sync_read)
 524                         error = wait_on_bio_chain(&bio);
 525                 if (error)
 526                         break;
 527                 if (!(nr_pages % m))
 528                         printk("\b\b\b\b%3d%%", nr_pages / m);
 529                 nr_pages++;
 530         }
 531         err2 = wait_on_bio_chain(&bio);
 532         do_gettimeofday(&stop);
 533         if (!error)
 534                 error = err2;
 535         if (!error) {
 536                 printk("\b\b\b\bdone\n");
 537                 snapshot_write_finalize(snapshot);
 538                 if (!snapshot_image_loaded(snapshot))
 539                         error = -ENODATA;
 540         }
 541         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 542         return error;
 543 }
 544
 545 /**
 546  *      swsusp_read - read the hibernation image.
 547  *      @flags_p: flags passed by the "frozen" kernel in the image header should
 548  *                be written into this memeory location
 549  */
 550
 551 int swsusp_read(unsigned int *flags_p)
 552 {
 553         int error;
 554         struct swap_map_handle handle;
 555         struct snapshot_handle snapshot;
 556         struct swsusp_info *header;
 557
 558         *flags_p = swsusp_header->flags;
 559         if (IS_ERR(resume_bdev)) {
 560                 pr_debug("PM: Image device not initialised\n");
 561                 return PTR_ERR(resume_bdev);
 562         }
 563
 564         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 565         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 566         if (error < PAGE_SIZE)
 567                 return error < 0 ? error : -EFAULT;
 568         header = (struct swsusp_info *)data_of(snapshot);
 569         error = get_swap_reader(&handle, swsusp_header->image);
 570         if (!error)
 571                 error = swap_read_page(&handle, header, NULL);
 572         if (!error)
 573                 error = load_image(&handle, &snapshot, header->pages - 1);
 574         release_swap_reader(&handle);
 575
 576         blkdev_put(resume_bdev, FMODE_READ);
 577
 578         if (!error)
 579                 pr_debug("PM: Image successfully loaded\n");
 580         else
 581                 pr_debug("PM: Error %d resuming\n", error);
 582         return error;
 583 }
 584
 585 /**
 586  *      swsusp_check - Check for swsusp signature in the resume device
 587  */
 588
 589 int swsusp_check(void)
 590 {
 591         int error;
 592
 593         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 594         if (!IS_ERR(resume_bdev)) {
 595                 set_blocksize(resume_bdev, PAGE_SIZE);
 596                 memset(swsusp_header, 0, PAGE_SIZE);
 597                 error = bio_read_page(swsusp_resume_block,
 598                                         swsusp_header, NULL);
 599                 if (error)
 600                         return error;
 601
 602                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 603                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 604                         /* Reset swap signature now */
 605                         error = bio_write_page(swsusp_resume_block,
 606                                                 swsusp_header, NULL);
 607                 } else {
 608                         return -EINVAL;
 609                 }
 610                 if (error)
 611                         blkdev_put(resume_bdev, FMODE_READ);
 612                 else
 613                         pr_debug("PM: Signature found, resuming\n");
 614         } else {
 615                 error = PTR_ERR(resume_bdev);
 616         }
 617
 618         if (error)
 619                 pr_debug("PM: Error %d checking image file\n", error);
 620
 621         return error;
 622 }
 623
 624 /**
 625  *      swsusp_close - close swap device.
 626  */
 627
 628 void swsusp_close(fmode_t mode)
 629 {
 630         if (IS_ERR(resume_bdev)) {
 631                 pr_debug("PM: Image device not initialised\n");
 632                 return;
 633         }
 634
 635         blkdev_put(resume_bdev, mode);
 636 }
 637
 638 static int swsusp_header_init(void)
 639 {
 640         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
 641         if (!swsusp_header)
 642                 panic("Could not allocate memory for swsusp_header\n");
 643         return 0;
 644 }
 645
 646 core_initcall(swsusp_header_init);