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 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));
  42
  43 static struct swsusp_header *swsusp_header;
  44
  45 /*
  46  * General things
  47  */
  48
  49 static unsigned short root_swap = 0xffff;
  50 static struct block_device *resume_bdev;
  51
  52 /**
  53  *      submit - submit BIO request.
  54  *      @rw:    READ or WRITE.
  55  *      @off    physical offset of page.
  56  *      @page:  page we're reading or writing.
  57  *      @bio_chain: list of pending biod (for async reading)
  58  *
  59  *      Straight from the textbook - allocate and initialize the bio.
  60  *      If we're reading, make sure the page is marked as dirty.
  61  *      Then submit it and, if @bio_chain == NULL, wait.
  62  */
  63 static int submit(int rw, pgoff_t page_off, struct page *page,
  64                         struct bio **bio_chain)
  65 {
  66         struct bio *bio;
  67
  68         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  69         if (!bio)
  70                 return -ENOMEM;
  71         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  72         bio->bi_bdev = resume_bdev;
  73         bio->bi_end_io = end_swap_bio_read;
  74
  75         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  76                 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
  77                 bio_put(bio);
  78                 return -EFAULT;
  79         }
  80
  81         lock_page(page);
  82         bio_get(bio);
  83
  84         if (bio_chain == NULL) {
  85                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  86                 wait_on_page_locked(page);
  87                 if (rw == READ)
  88                         bio_set_pages_dirty(bio);
  89                 bio_put(bio);
  90         } else {
  91                 if (rw == READ)
  92                         get_page(page); /* These pages are freed later */
  93                 bio->bi_private = *bio_chain;
  94                 *bio_chain = bio;
  95                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  96         }
  97         return 0;
  98 }
  99
 100 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 101 {
 102         return submit(READ, page_off, virt_to_page(addr), bio_chain);
 103 }
 104
 105 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 106 {
 107         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
 108 }
 109
 110 static int wait_on_bio_chain(struct bio **bio_chain)
 111 {
 112         struct bio *bio;
 113         struct bio *next_bio;
 114         int ret = 0;
 115
 116         if (bio_chain == NULL)
 117                 return 0;
 118
 119         bio = *bio_chain;
 120         if (bio == NULL)
 121                 return 0;
 122         while (bio) {
 123                 struct page *page;
 124
 125                 next_bio = bio->bi_private;
 126                 page = bio->bi_io_vec[0].bv_page;
 127                 wait_on_page_locked(page);
 128                 if (!PageUptodate(page) || PageError(page))
 129                         ret = -EIO;
 130                 put_page(page);
 131                 bio_put(bio);
 132                 bio = next_bio;
 133         }
 134         *bio_chain = NULL;
 135         return ret;
 136 }
 137
 138 /*
 139  * Saving part
 140  */
 141
 142 static int mark_swapfiles(sector_t start)
 143 {
 144         int error;
 145
 146         bio_read_page(swsusp_resume_block, swsusp_header, NULL);
 147         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 148             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 149                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 150                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
 151                 swsusp_header->image = start;
 152                 error = bio_write_page(swsusp_resume_block,
 153                                         swsusp_header, NULL);
 154         } else {
 155                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 156                 error = -ENODEV;
 157         }
 158         return error;
 159 }
 160
 161 /**
 162  *      swsusp_swap_check - check if the resume device is a swap device
 163  *      and get its index (if so)
 164  */
 165
 166 static int swsusp_swap_check(void) /* This is called before saving image */
 167 {
 168         int res;
 169
 170         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 171                         &resume_bdev);
 172         if (res < 0)
 173                 return res;
 174
 175         root_swap = res;
 176         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
 177         if (res)
 178                 return res;
 179
 180         res = set_blocksize(resume_bdev, PAGE_SIZE);
 181         if (res < 0)
 182                 blkdev_put(resume_bdev);
 183
 184         return res;
 185 }
 186
 187 /**
 188  *      write_page - Write one page to given swap location.
 189  *      @buf:           Address we're writing.
 190  *      @offset:        Offset of the swap page we're writing to.
 191  *      @bio_chain:     Link the next write BIO here
 192  */
 193
 194 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 195 {
 196         void *src;
 197
 198         if (!offset)
 199                 return -ENOSPC;
 200
 201         if (bio_chain) {
 202                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 203                 if (src) {
 204                         memcpy(src, buf, PAGE_SIZE);
 205                 } else {
 206                         WARN_ON_ONCE(1);
 207                         bio_chain = NULL;       /* Go synchronous */
 208                         src = buf;
 209                 }
 210         } else {
 211                 src = buf;
 212         }
 213         return bio_write_page(offset, src, bio_chain);
 214 }
 215
 216 /*
 217  *      The swap map is a data structure used for keeping track of each page
 218  *      written to a swap partition.  It consists of many swap_map_page
 219  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 220  *      These structures are stored on the swap and linked together with the
 221  *      help of the .next_swap member.
 222  *
 223  *      The swap map is created during suspend.  The swap map pages are
 224  *      allocated and populated one at a time, so we only need one memory
 225  *      page to set up the entire structure.
 226  *
 227  *      During resume we also only need to use one swap_map_page structure
 228  *      at a time.
 229  */
 230
 231 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 232
 233 struct swap_map_page {
 234         sector_t entries[MAP_PAGE_ENTRIES];
 235         sector_t next_swap;
 236 };
 237
 238 /**
 239  *      The swap_map_handle structure is used for handling swap in
 240  *      a file-alike way
 241  */
 242
 243 struct swap_map_handle {
 244         struct swap_map_page *cur;
 245         sector_t cur_swap;
 246         struct bitmap_page *bitmap;
 247         unsigned int k;
 248 };
 249
 250 static void release_swap_writer(struct swap_map_handle *handle)
 251 {
 252         if (handle->cur)
 253                 free_page((unsigned long)handle->cur);
 254         handle->cur = NULL;
 255         if (handle->bitmap)
 256                 free_bitmap(handle->bitmap);
 257         handle->bitmap = NULL;
 258 }
 259
 260 static int get_swap_writer(struct swap_map_handle *handle)
 261 {
 262         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 263         if (!handle->cur)
 264                 return -ENOMEM;
 265         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 266         if (!handle->bitmap) {
 267                 release_swap_writer(handle);
 268                 return -ENOMEM;
 269         }
 270         handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
 271         if (!handle->cur_swap) {
 272                 release_swap_writer(handle);
 273                 return -ENOSPC;
 274         }
 275         handle->k = 0;
 276         return 0;
 277 }
 278
 279 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 280                                 struct bio **bio_chain)
 281 {
 282         int error = 0;
 283         sector_t offset;
 284
 285         if (!handle->cur)
 286                 return -EINVAL;
 287         offset = alloc_swapdev_block(root_swap, handle->bitmap);
 288         error = write_page(buf, offset, bio_chain);
 289         if (error)
 290                 return error;
 291         handle->cur->entries[handle->k++] = offset;
 292         if (handle->k >= MAP_PAGE_ENTRIES) {
 293                 error = wait_on_bio_chain(bio_chain);
 294                 if (error)
 295                         goto out;
 296                 offset = alloc_swapdev_block(root_swap, handle->bitmap);
 297                 if (!offset)
 298                         return -ENOSPC;
 299                 handle->cur->next_swap = offset;
 300                 error = write_page(handle->cur, handle->cur_swap, NULL);
 301                 if (error)
 302                         goto out;
 303                 memset(handle->cur, 0, PAGE_SIZE);
 304                 handle->cur_swap = offset;
 305                 handle->k = 0;
 306         }
 307  out:
 308         return error;
 309 }
 310
 311 static int flush_swap_writer(struct swap_map_handle *handle)
 312 {
 313         if (handle->cur && handle->cur_swap)
 314                 return write_page(handle->cur, handle->cur_swap, NULL);
 315         else
 316                 return -EINVAL;
 317 }
 318
 319 /**
 320  *      save_image - save the suspend image data
 321  */
 322
 323 static int save_image(struct swap_map_handle *handle,
 324                       struct snapshot_handle *snapshot,
 325                       unsigned int nr_to_write)
 326 {
 327         unsigned int m;
 328         int ret;
 329         int error = 0;
 330         int nr_pages;
 331         int err2;
 332         struct bio *bio;
 333         struct timeval start;
 334         struct timeval stop;
 335
 336         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 337         m = nr_to_write / 100;
 338         if (!m)
 339                 m = 1;
 340         nr_pages = 0;
 341         bio = NULL;
 342         do_gettimeofday(&start);
 343         do {
 344                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 345                 if (ret > 0) {
 346                         error = swap_write_page(handle, data_of(*snapshot),
 347                                                 &bio);
 348                         if (error)
 349                                 break;
 350                         if (!(nr_pages % m))
 351                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 352                         nr_pages++;
 353                 }
 354         } while (ret > 0);
 355         err2 = wait_on_bio_chain(&bio);
 356         do_gettimeofday(&stop);
 357         if (!error)
 358                 error = err2;
 359         if (!error)
 360                 printk("\b\b\b\bdone\n");
 361         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 362         return error;
 363 }
 364
 365 /**
 366  *      enough_swap - Make sure we have enough swap to save the image.
 367  *
 368  *      Returns TRUE or FALSE after checking the total amount of swap
 369  *      space avaiable from the resume partition.
 370  */
 371
 372 static int enough_swap(unsigned int nr_pages)
 373 {
 374         unsigned int free_swap = count_swap_pages(root_swap, 1);
 375
 376         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 377         return free_swap > nr_pages + PAGES_FOR_IO;
 378 }
 379
 380 /**
 381  *      swsusp_write - Write entire image and metadata.
 382  *
 383  *      It is important _NOT_ to umount filesystems at this point. We want
 384  *      them synced (in case something goes wrong) but we DO not want to mark
 385  *      filesystem clean: it is not. (And it does not matter, if we resume
 386  *      correctly, we'll mark system clean, anyway.)
 387  */
 388
 389 int swsusp_write(void)
 390 {
 391         struct swap_map_handle handle;
 392         struct snapshot_handle snapshot;
 393         struct swsusp_info *header;
 394         int error;
 395
 396         error = swsusp_swap_check();
 397         if (error) {
 398                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 399                                 "swapon -a.\n");
 400                 return error;
 401         }
 402         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 403         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 404         if (error < PAGE_SIZE) {
 405                 if (error >= 0)
 406                         error = -EFAULT;
 407
 408                 goto out;
 409         }
 410         header = (struct swsusp_info *)data_of(snapshot);
 411         if (!enough_swap(header->pages)) {
 412                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 413                 error = -ENOSPC;
 414                 goto out;
 415         }
 416         error = get_swap_writer(&handle);
 417         if (!error) {
 418                 sector_t start = handle.cur_swap;
 419
 420                 error = swap_write_page(&handle, header, NULL);
 421                 if (!error)
 422                         error = save_image(&handle, &snapshot,
 423                                         header->pages - 1);
 424
 425                 if (!error) {
 426                         flush_swap_writer(&handle);
 427                         printk("S");
 428                         error = mark_swapfiles(start);
 429                         printk("|\n");
 430                 }
 431         }
 432         if (error)
 433                 free_all_swap_pages(root_swap, handle.bitmap);
 434         release_swap_writer(&handle);
 435  out:
 436         swsusp_close();
 437         return error;
 438 }
 439
 440 /**
 441  *      The following functions allow us to read data using a swap map
 442  *      in a file-alike way
 443  */
 444
 445 static void release_swap_reader(struct swap_map_handle *handle)
 446 {
 447         if (handle->cur)
 448                 free_page((unsigned long)handle->cur);
 449         handle->cur = NULL;
 450 }
 451
 452 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 453 {
 454         int error;
 455
 456         if (!start)
 457                 return -EINVAL;
 458
 459         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 460         if (!handle->cur)
 461                 return -ENOMEM;
 462
 463         error = bio_read_page(start, handle->cur, NULL);
 464         if (error) {
 465                 release_swap_reader(handle);
 466                 return error;
 467         }
 468         handle->k = 0;
 469         return 0;
 470 }
 471
 472 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 473                                 struct bio **bio_chain)
 474 {
 475         sector_t offset;
 476         int error;
 477
 478         if (!handle->cur)
 479                 return -EINVAL;
 480         offset = handle->cur->entries[handle->k];
 481         if (!offset)
 482                 return -EFAULT;
 483         error = bio_read_page(offset, buf, bio_chain);
 484         if (error)
 485                 return error;
 486         if (++handle->k >= MAP_PAGE_ENTRIES) {
 487                 error = wait_on_bio_chain(bio_chain);
 488                 handle->k = 0;
 489                 offset = handle->cur->next_swap;
 490                 if (!offset)
 491                         release_swap_reader(handle);
 492                 else if (!error)
 493                         error = bio_read_page(offset, handle->cur, NULL);
 494         }
 495         return error;
 496 }
 497
 498 /**
 499  *      load_image - load the image using the swap map handle
 500  *      @handle and the snapshot handle @snapshot
 501  *      (assume there are @nr_pages pages to load)
 502  */
 503
 504 static int load_image(struct swap_map_handle *handle,
 505                       struct snapshot_handle *snapshot,
 506                       unsigned int nr_to_read)
 507 {
 508         unsigned int m;
 509         int error = 0;
 510         struct timeval start;
 511         struct timeval stop;
 512         struct bio *bio;
 513         int err2;
 514         unsigned nr_pages;
 515
 516         printk("Loading image data pages (%u pages) ...     ", nr_to_read);
 517         m = nr_to_read / 100;
 518         if (!m)
 519                 m = 1;
 520         nr_pages = 0;
 521         bio = NULL;
 522         do_gettimeofday(&start);
 523         for ( ; ; ) {
 524                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 525                 if (error <= 0)
 526                         break;
 527                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 528                 if (error)
 529                         break;
 530                 if (snapshot->sync_read)
 531                         error = wait_on_bio_chain(&bio);
 532                 if (error)
 533                         break;
 534                 if (!(nr_pages % m))
 535                         printk("\b\b\b\b%3d%%", nr_pages / m);
 536                 nr_pages++;
 537         }
 538         err2 = wait_on_bio_chain(&bio);
 539         do_gettimeofday(&stop);
 540         if (!error)
 541                 error = err2;
 542         if (!error) {
 543                 printk("\b\b\b\bdone\n");
 544                 snapshot_write_finalize(snapshot);
 545                 if (!snapshot_image_loaded(snapshot))
 546                         error = -ENODATA;
 547         }
 548         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 549         return error;
 550 }
 551
 552 int swsusp_read(void)
 553 {
 554         int error;
 555         struct swap_map_handle handle;
 556         struct snapshot_handle snapshot;
 557         struct swsusp_info *header;
 558
 559         if (IS_ERR(resume_bdev)) {
 560                 pr_debug("swsusp: block 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);
 577
 578         if (!error)
 579                 pr_debug("swsusp: Reading resume file was successful\n");
 580         else
 581                 pr_debug("swsusp: 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, sizeof(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);
 612                 else
 613                         pr_debug("swsusp: Signature found, resuming\n");
 614         } else {
 615                 error = PTR_ERR(resume_bdev);
 616         }
 617
 618         if (error)
 619                 pr_debug("swsusp: Error %d check for resume file\n", error);
 620
 621         return error;
 622 }
 623
 624 /**
 625  *      swsusp_close - close swap device.
 626  */
 627
 628 void swsusp_close(void)
 629 {
 630         if (IS_ERR(resume_bdev)) {
 631                 pr_debug("swsusp: block device not initialised\n");
 632                 return;
 633         }
 634
 635         blkdev_put(resume_bdev);
 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);