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                         &resume_bdev);
 170         if (res < 0)
 171                 return res;
 172
 173         root_swap = res;
 174         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
 175         if (res)
 176                 return res;
 177
 178         res = set_blocksize(resume_bdev, PAGE_SIZE);
 179         if (res < 0)
 180                 blkdev_put(resume_bdev);
 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         struct bitmap_page *bitmap;
 245         unsigned int k;
 246 };
 247
 248 static void release_swap_writer(struct swap_map_handle *handle)
 249 {
 250         if (handle->cur)
 251                 free_page((unsigned long)handle->cur);
 252         handle->cur = NULL;
 253         if (handle->bitmap)
 254                 free_bitmap(handle->bitmap);
 255         handle->bitmap = NULL;
 256 }
 257
 258 static int get_swap_writer(struct swap_map_handle *handle)
 259 {
 260         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 261         if (!handle->cur)
 262                 return -ENOMEM;
 263         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 264         if (!handle->bitmap) {
 265                 release_swap_writer(handle);
 266                 return -ENOMEM;
 267         }
 268         handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
 269         if (!handle->cur_swap) {
 270                 release_swap_writer(handle);
 271                 return -ENOSPC;
 272         }
 273         handle->k = 0;
 274         return 0;
 275 }
 276
 277 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 278                                 struct bio **bio_chain)
 279 {
 280         int error = 0;
 281         sector_t offset;
 282
 283         if (!handle->cur)
 284                 return -EINVAL;
 285         offset = alloc_swapdev_block(root_swap, handle->bitmap);
 286         error = write_page(buf, offset, bio_chain);
 287         if (error)
 288                 return error;
 289         handle->cur->entries[handle->k++] = offset;
 290         if (handle->k >= MAP_PAGE_ENTRIES) {
 291                 error = wait_on_bio_chain(bio_chain);
 292                 if (error)
 293                         goto out;
 294                 offset = alloc_swapdev_block(root_swap, handle->bitmap);
 295                 if (!offset)
 296                         return -ENOSPC;
 297                 handle->cur->next_swap = offset;
 298                 error = write_page(handle->cur, handle->cur_swap, NULL);
 299                 if (error)
 300                         goto out;
 301                 memset(handle->cur, 0, PAGE_SIZE);
 302                 handle->cur_swap = offset;
 303                 handle->k = 0;
 304         }
 305  out:
 306         return error;
 307 }
 308
 309 static int flush_swap_writer(struct swap_map_handle *handle)
 310 {
 311         if (handle->cur && handle->cur_swap)
 312                 return write_page(handle->cur, handle->cur_swap, NULL);
 313         else
 314                 return -EINVAL;
 315 }
 316
 317 /**
 318  *      save_image - save the suspend image data
 319  */
 320
 321 static int save_image(struct swap_map_handle *handle,
 322                       struct snapshot_handle *snapshot,
 323                       unsigned int nr_to_write)
 324 {
 325         unsigned int m;
 326         int ret;
 327         int error = 0;
 328         int nr_pages;
 329         int err2;
 330         struct bio *bio;
 331         struct timeval start;
 332         struct timeval stop;
 333
 334         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 335         m = nr_to_write / 100;
 336         if (!m)
 337                 m = 1;
 338         nr_pages = 0;
 339         bio = NULL;
 340         do_gettimeofday(&start);
 341         do {
 342                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 343                 if (ret > 0) {
 344                         error = swap_write_page(handle, data_of(*snapshot),
 345                                                 &bio);
 346                         if (error)
 347                                 break;
 348                         if (!(nr_pages % m))
 349                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 350                         nr_pages++;
 351                 }
 352         } while (ret > 0);
 353         err2 = wait_on_bio_chain(&bio);
 354         do_gettimeofday(&stop);
 355         if (!error)
 356                 error = err2;
 357         if (!error)
 358                 printk("\b\b\b\bdone\n");
 359         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 360         return error;
 361 }
 362
 363 /**
 364  *      enough_swap - Make sure we have enough swap to save the image.
 365  *
 366  *      Returns TRUE or FALSE after checking the total amount of swap
 367  *      space avaiable from the resume partition.
 368  */
 369
 370 static int enough_swap(unsigned int nr_pages)
 371 {
 372         unsigned int free_swap = count_swap_pages(root_swap, 1);
 373
 374         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 375         return free_swap > nr_pages + PAGES_FOR_IO;
 376 }
 377
 378 /**
 379  *      swsusp_write - Write entire image and metadata.
 380  *
 381  *      It is important _NOT_ to umount filesystems at this point. We want
 382  *      them synced (in case something goes wrong) but we DO not want to mark
 383  *      filesystem clean: it is not. (And it does not matter, if we resume
 384  *      correctly, we'll mark system clean, anyway.)
 385  */
 386
 387 int swsusp_write(void)
 388 {
 389         struct swap_map_handle handle;
 390         struct snapshot_handle snapshot;
 391         struct swsusp_info *header;
 392         int error;
 393
 394         error = swsusp_swap_check();
 395         if (error) {
 396                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 397                                 "swapon -a.\n");
 398                 return error;
 399         }
 400         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 401         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 402         if (error < PAGE_SIZE) {
 403                 if (error >= 0)
 404                         error = -EFAULT;
 405
 406                 goto out;
 407         }
 408         header = (struct swsusp_info *)data_of(snapshot);
 409         if (!enough_swap(header->pages)) {
 410                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 411                 error = -ENOSPC;
 412                 goto out;
 413         }
 414         error = get_swap_writer(&handle);
 415         if (!error) {
 416                 sector_t start = handle.cur_swap;
 417
 418                 error = swap_write_page(&handle, header, NULL);
 419                 if (!error)
 420                         error = save_image(&handle, &snapshot,
 421                                         header->pages - 1);
 422
 423                 if (!error) {
 424                         flush_swap_writer(&handle);
 425                         printk("S");
 426                         error = mark_swapfiles(start);
 427                         printk("|\n");
 428                 }
 429         }
 430         if (error)
 431                 free_all_swap_pages(root_swap, handle.bitmap);
 432         release_swap_writer(&handle);
 433  out:
 434         swsusp_close();
 435         return error;
 436 }
 437
 438 /**
 439  *      The following functions allow us to read data using a swap map
 440  *      in a file-alike way
 441  */
 442
 443 static void release_swap_reader(struct swap_map_handle *handle)
 444 {
 445         if (handle->cur)
 446                 free_page((unsigned long)handle->cur);
 447         handle->cur = NULL;
 448 }
 449
 450 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 451 {
 452         int error;
 453
 454         if (!start)
 455                 return -EINVAL;
 456
 457         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 458         if (!handle->cur)
 459                 return -ENOMEM;
 460
 461         error = bio_read_page(start, handle->cur, NULL);
 462         if (error) {
 463                 release_swap_reader(handle);
 464                 return error;
 465         }
 466         handle->k = 0;
 467         return 0;
 468 }
 469
 470 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 471                                 struct bio **bio_chain)
 472 {
 473         sector_t offset;
 474         int error;
 475
 476         if (!handle->cur)
 477                 return -EINVAL;
 478         offset = handle->cur->entries[handle->k];
 479         if (!offset)
 480                 return -EFAULT;
 481         error = bio_read_page(offset, buf, bio_chain);
 482         if (error)
 483                 return error;
 484         if (++handle->k >= MAP_PAGE_ENTRIES) {
 485                 error = wait_on_bio_chain(bio_chain);
 486                 handle->k = 0;
 487                 offset = handle->cur->next_swap;
 488                 if (!offset)
 489                         release_swap_reader(handle);
 490                 else if (!error)
 491                         error = bio_read_page(offset, handle->cur, NULL);
 492         }
 493         return error;
 494 }
 495
 496 /**
 497  *      load_image - load the image using the swap map handle
 498  *      @handle and the snapshot handle @snapshot
 499  *      (assume there are @nr_pages pages to load)
 500  */
 501
 502 static int load_image(struct swap_map_handle *handle,
 503                       struct snapshot_handle *snapshot,
 504                       unsigned int nr_to_read)
 505 {
 506         unsigned int m;
 507         int error = 0;
 508         struct timeval start;
 509         struct timeval stop;
 510         struct bio *bio;
 511         int err2;
 512         unsigned nr_pages;
 513
 514         printk("Loading image data pages (%u pages) ...     ", nr_to_read);
 515         m = nr_to_read / 100;
 516         if (!m)
 517                 m = 1;
 518         nr_pages = 0;
 519         bio = NULL;
 520         do_gettimeofday(&start);
 521         for ( ; ; ) {
 522                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 523                 if (error <= 0)
 524                         break;
 525                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 526                 if (error)
 527                         break;
 528                 if (snapshot->sync_read)
 529                         error = wait_on_bio_chain(&bio);
 530                 if (error)
 531                         break;
 532                 if (!(nr_pages % m))
 533                         printk("\b\b\b\b%3d%%", nr_pages / m);
 534                 nr_pages++;
 535         }
 536         err2 = wait_on_bio_chain(&bio);
 537         do_gettimeofday(&stop);
 538         if (!error)
 539                 error = err2;
 540         if (!error) {
 541                 printk("\b\b\b\bdone\n");
 542                 snapshot_write_finalize(snapshot);
 543                 if (!snapshot_image_loaded(snapshot))
 544                         error = -ENODATA;
 545         }
 546         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 547         return error;
 548 }
 549
 550 int swsusp_read(void)
 551 {
 552         int error;
 553         struct swap_map_handle handle;
 554         struct snapshot_handle snapshot;
 555         struct swsusp_info *header;
 556
 557         if (IS_ERR(resume_bdev)) {
 558                 pr_debug("swsusp: block device not initialised\n");
 559                 return PTR_ERR(resume_bdev);
 560         }
 561
 562         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 563         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 564         if (error < PAGE_SIZE)
 565                 return error < 0 ? error : -EFAULT;
 566         header = (struct swsusp_info *)data_of(snapshot);
 567         error = get_swap_reader(&handle, swsusp_header.image);
 568         if (!error)
 569                 error = swap_read_page(&handle, header, NULL);
 570         if (!error)
 571                 error = load_image(&handle, &snapshot, header->pages - 1);
 572         release_swap_reader(&handle);
 573
 574         blkdev_put(resume_bdev);
 575
 576         if (!error)
 577                 pr_debug("swsusp: Reading resume file was successful\n");
 578         else
 579                 pr_debug("swsusp: Error %d resuming\n", error);
 580         return error;
 581 }
 582
 583 /**
 584  *      swsusp_check - Check for swsusp signature in the resume device
 585  */
 586
 587 int swsusp_check(void)
 588 {
 589         int error;
 590
 591         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 592         if (!IS_ERR(resume_bdev)) {
 593                 set_blocksize(resume_bdev, PAGE_SIZE);
 594                 memset(&swsusp_header, 0, sizeof(swsusp_header));
 595                 error = bio_read_page(swsusp_resume_block,
 596                                         &swsusp_header, NULL);
 597                 if (error)
 598                         return error;
 599
 600                 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 601                         memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 602                         /* Reset swap signature now */
 603                         error = bio_write_page(swsusp_resume_block,
 604                                                 &swsusp_header, NULL);
 605                 } else {
 606                         return -EINVAL;
 607                 }
 608                 if (error)
 609                         blkdev_put(resume_bdev);
 610                 else
 611                         pr_debug("swsusp: Signature found, resuming\n");
 612         } else {
 613                 error = PTR_ERR(resume_bdev);
 614         }
 615
 616         if (error)
 617                 pr_debug("swsusp: Error %d check for resume file\n", error);
 618
 619         return error;
 620 }
 621
 622 /**
 623  *      swsusp_close - close swap device.
 624  */
 625
 626 void swsusp_close(void)
 627 {
 628         if (IS_ERR(resume_bdev)) {
 629                 pr_debug("swsusp: block device not initialised\n");
 630                 return;
 631         }
 632
 633         blkdev_put(resume_bdev);
 634 }