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/version.h>
  18 #include <linux/delay.h>
  19 #include <linux/bitops.h>
  20 #include <linux/genhd.h>
  21 #include <linux/device.h>
  22 #include <linux/buffer_head.h>
  23 #include <linux/bio.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/swap.h>
  26 #include <linux/swapops.h>
  27 #include <linux/pm.h>
  28
  29 #include "power.h"
  30
  31 extern char resume_file[];
  32
  33 #define SWSUSP_SIG      "S1SUSPEND"
  34
  35 struct swsusp_header {
  36         char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
  37         sector_t image;
  38         char    orig_sig[10];
  39         char    sig[10];
  40 } __attribute__((packed));
  41
  42 static struct swsusp_header *swsusp_header;
  43
  44 /*
  45  * General things
  46  */
  47
  48 static unsigned short root_swap = 0xffff;
  49 static struct block_device *resume_bdev;
  50
  51 /**
  52  *      submit - submit BIO request.
  53  *      @rw:    READ or WRITE.
  54  *      @off    physical offset of page.
  55  *      @page:  page we're reading or writing.
  56  *      @bio_chain: list of pending biod (for async reading)
  57  *
  58  *      Straight from the textbook - allocate and initialize the bio.
  59  *      If we're reading, make sure the page is marked as dirty.
  60  *      Then submit it and, if @bio_chain == NULL, wait.
  61  */
  62 static int submit(int rw, pgoff_t page_off, struct page *page,
  63                         struct bio **bio_chain)
  64 {
  65         struct bio *bio;
  66
  67         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  68         if (!bio)
  69                 return -ENOMEM;
  70         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  71         bio->bi_bdev = resume_bdev;
  72         bio->bi_end_io = end_swap_bio_read;
  73
  74         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  75                 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
  76                 bio_put(bio);
  77                 return -EFAULT;
  78         }
  79
  80         lock_page(page);
  81         bio_get(bio);
  82
  83         if (bio_chain == NULL) {
  84                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  85                 wait_on_page_locked(page);
  86                 if (rw == READ)
  87                         bio_set_pages_dirty(bio);
  88                 bio_put(bio);
  89         } else {
  90                 if (rw == READ)
  91                         get_page(page); /* These pages are freed later */
  92                 bio->bi_private = *bio_chain;
  93                 *bio_chain = bio;
  94                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
  95         }
  96         return 0;
  97 }
  98
  99 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 100 {
 101         return submit(READ, page_off, virt_to_page(addr), bio_chain);
 102 }
 103
 104 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 105 {
 106         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
 107 }
 108
 109 static int wait_on_bio_chain(struct bio **bio_chain)
 110 {
 111         struct bio *bio;
 112         struct bio *next_bio;
 113         int ret = 0;
 114
 115         if (bio_chain == NULL)
 116                 return 0;
 117
 118         bio = *bio_chain;
 119         if (bio == NULL)
 120                 return 0;
 121         while (bio) {
 122                 struct page *page;
 123
 124                 next_bio = bio->bi_private;
 125                 page = bio->bi_io_vec[0].bv_page;
 126                 wait_on_page_locked(page);
 127                 if (!PageUptodate(page) || PageError(page))
 128                         ret = -EIO;
 129                 put_page(page);
 130                 bio_put(bio);
 131                 bio = next_bio;
 132         }
 133         *bio_chain = NULL;
 134         return ret;
 135 }
 136
 137 /*
 138  * Saving part
 139  */
 140
 141 static int mark_swapfiles(sector_t start)
 142 {
 143         int error;
 144
 145         bio_read_page(swsusp_resume_block, swsusp_header, NULL);
 146         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 147             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 148                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 149                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
 150                 swsusp_header->image = start;
 151                 error = bio_write_page(swsusp_resume_block,
 152                                         swsusp_header, NULL);
 153         } else {
 154                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 155                 error = -ENODEV;
 156         }
 157         return error;
 158 }
 159
 160 /**
 161  *      swsusp_swap_check - check if the resume device is a swap device
 162  *      and get its index (if so)
 163  */
 164
 165 static int swsusp_swap_check(void) /* This is called before saving image */
 166 {
 167         int res;
 168
 169         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 170                         &resume_bdev);
 171         if (res < 0)
 172                 return res;
 173
 174         root_swap = res;
 175         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
 176         if (res)
 177                 return res;
 178
 179         res = set_blocksize(resume_bdev, PAGE_SIZE);
 180         if (res < 0)
 181                 blkdev_put(resume_bdev);
 182
 183         return res;
 184 }
 185
 186 /**
 187  *      write_page - Write one page to given swap location.
 188  *      @buf:           Address we're writing.
 189  *      @offset:        Offset of the swap page we're writing to.
 190  *      @bio_chain:     Link the next write BIO here
 191  */
 192
 193 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 194 {
 195         void *src;
 196
 197         if (!offset)
 198                 return -ENOSPC;
 199
 200         if (bio_chain) {
 201                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 202                 if (src) {
 203                         memcpy(src, buf, PAGE_SIZE);
 204                 } else {
 205                         WARN_ON_ONCE(1);
 206                         bio_chain = NULL;       /* Go synchronous */
 207                         src = buf;
 208                 }
 209         } else {
 210                 src = buf;
 211         }
 212         return bio_write_page(offset, src, bio_chain);
 213 }
 214
 215 /*
 216  *      The swap map is a data structure used for keeping track of each page
 217  *      written to a swap partition.  It consists of many swap_map_page
 218  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 219  *      These structures are stored on the swap and linked together with the
 220  *      help of the .next_swap member.
 221  *
 222  *      The swap map is created during suspend.  The swap map pages are
 223  *      allocated and populated one at a time, so we only need one memory
 224  *      page to set up the entire structure.
 225  *
 226  *      During resume we also only need to use one swap_map_page structure
 227  *      at a time.
 228  */
 229
 230 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 231
 232 struct swap_map_page {
 233         sector_t entries[MAP_PAGE_ENTRIES];
 234         sector_t next_swap;
 235 };
 236
 237 /**
 238  *      The swap_map_handle structure is used for handling swap in
 239  *      a file-alike way
 240  */
 241
 242 struct swap_map_handle {
 243         struct swap_map_page *cur;
 244         sector_t cur_swap;
 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 }
 254
 255 static int get_swap_writer(struct swap_map_handle *handle)
 256 {
 257         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 258         if (!handle->cur)
 259                 return -ENOMEM;
 260         handle->cur_swap = alloc_swapdev_block(root_swap);
 261         if (!handle->cur_swap) {
 262                 release_swap_writer(handle);
 263                 return -ENOSPC;
 264         }
 265         handle->k = 0;
 266         return 0;
 267 }
 268
 269 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 270                                 struct bio **bio_chain)
 271 {
 272         int error = 0;
 273         sector_t offset;
 274
 275         if (!handle->cur)
 276                 return -EINVAL;
 277         offset = alloc_swapdev_block(root_swap);
 278         error = write_page(buf, offset, bio_chain);
 279         if (error)
 280                 return error;
 281         handle->cur->entries[handle->k++] = offset;
 282         if (handle->k >= MAP_PAGE_ENTRIES) {
 283                 error = wait_on_bio_chain(bio_chain);
 284                 if (error)
 285                         goto out;
 286                 offset = alloc_swapdev_block(root_swap);
 287                 if (!offset)
 288                         return -ENOSPC;
 289                 handle->cur->next_swap = offset;
 290                 error = write_page(handle->cur, handle->cur_swap, NULL);
 291                 if (error)
 292                         goto out;
 293                 memset(handle->cur, 0, PAGE_SIZE);
 294                 handle->cur_swap = offset;
 295                 handle->k = 0;
 296         }
 297  out:
 298         return error;
 299 }
 300
 301 static int flush_swap_writer(struct swap_map_handle *handle)
 302 {
 303         if (handle->cur && handle->cur_swap)
 304                 return write_page(handle->cur, handle->cur_swap, NULL);
 305         else
 306                 return -EINVAL;
 307 }
 308
 309 /**
 310  *      save_image - save the suspend image data
 311  */
 312
 313 static int save_image(struct swap_map_handle *handle,
 314                       struct snapshot_handle *snapshot,
 315                       unsigned int nr_to_write)
 316 {
 317         unsigned int m;
 318         int ret;
 319         int error = 0;
 320         int nr_pages;
 321         int err2;
 322         struct bio *bio;
 323         struct timeval start;
 324         struct timeval stop;
 325
 326         printk("Saving image data pages (%u pages) ...     ", 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("swsusp: 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  *
 373  *      It is important _NOT_ to umount filesystems at this point. We want
 374  *      them synced (in case something goes wrong) but we DO not want to mark
 375  *      filesystem clean: it is not. (And it does not matter, if we resume
 376  *      correctly, we'll mark system clean, anyway.)
 377  */
 378
 379 int swsusp_write(void)
 380 {
 381         struct swap_map_handle handle;
 382         struct snapshot_handle snapshot;
 383         struct swsusp_info *header;
 384         int error;
 385
 386         error = swsusp_swap_check();
 387         if (error) {
 388                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 389                                 "swapon -a.\n");
 390                 return error;
 391         }
 392         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 393         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 394         if (error < PAGE_SIZE) {
 395                 if (error >= 0)
 396                         error = -EFAULT;
 397
 398                 goto out;
 399         }
 400         header = (struct swsusp_info *)data_of(snapshot);
 401         if (!enough_swap(header->pages)) {
 402                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 403                 error = -ENOSPC;
 404                 goto out;
 405         }
 406         error = get_swap_writer(&handle);
 407         if (!error) {
 408                 sector_t start = handle.cur_swap;
 409
 410                 error = swap_write_page(&handle, header, NULL);
 411                 if (!error)
 412                         error = save_image(&handle, &snapshot,
 413                                         header->pages - 1);
 414
 415                 if (!error) {
 416                         flush_swap_writer(&handle);
 417                         printk("S");
 418                         error = mark_swapfiles(start);
 419                         printk("|\n");
 420                 }
 421         }
 422         if (error)
 423                 free_all_swap_pages(root_swap);
 424
 425         release_swap_writer(&handle);
 426  out:
 427         swsusp_close();
 428         return error;
 429 }
 430
 431 /**
 432  *      The following functions allow us to read data using a swap map
 433  *      in a file-alike way
 434  */
 435
 436 static void release_swap_reader(struct swap_map_handle *handle)
 437 {
 438         if (handle->cur)
 439                 free_page((unsigned long)handle->cur);
 440         handle->cur = NULL;
 441 }
 442
 443 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 444 {
 445         int error;
 446
 447         if (!start)
 448                 return -EINVAL;
 449
 450         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 451         if (!handle->cur)
 452                 return -ENOMEM;
 453
 454         error = bio_read_page(start, handle->cur, NULL);
 455         if (error) {
 456                 release_swap_reader(handle);
 457                 return error;
 458         }
 459         handle->k = 0;
 460         return 0;
 461 }
 462
 463 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 464                                 struct bio **bio_chain)
 465 {
 466         sector_t offset;
 467         int error;
 468
 469         if (!handle->cur)
 470                 return -EINVAL;
 471         offset = handle->cur->entries[handle->k];
 472         if (!offset)
 473                 return -EFAULT;
 474         error = bio_read_page(offset, buf, bio_chain);
 475         if (error)
 476                 return error;
 477         if (++handle->k >= MAP_PAGE_ENTRIES) {
 478                 error = wait_on_bio_chain(bio_chain);
 479                 handle->k = 0;
 480                 offset = handle->cur->next_swap;
 481                 if (!offset)
 482                         release_swap_reader(handle);
 483                 else if (!error)
 484                         error = bio_read_page(offset, handle->cur, NULL);
 485         }
 486         return error;
 487 }
 488
 489 /**
 490  *      load_image - load the image using the swap map handle
 491  *      @handle and the snapshot handle @snapshot
 492  *      (assume there are @nr_pages pages to load)
 493  */
 494
 495 static int load_image(struct swap_map_handle *handle,
 496                       struct snapshot_handle *snapshot,
 497                       unsigned int nr_to_read)
 498 {
 499         unsigned int m;
 500         int error = 0;
 501         struct timeval start;
 502         struct timeval stop;
 503         struct bio *bio;
 504         int err2;
 505         unsigned nr_pages;
 506
 507         printk("Loading image data pages (%u pages) ...     ", nr_to_read);
 508         m = nr_to_read / 100;
 509         if (!m)
 510                 m = 1;
 511         nr_pages = 0;
 512         bio = NULL;
 513         do_gettimeofday(&start);
 514         for ( ; ; ) {
 515                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 516                 if (error <= 0)
 517                         break;
 518                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 519                 if (error)
 520                         break;
 521                 if (snapshot->sync_read)
 522                         error = wait_on_bio_chain(&bio);
 523                 if (error)
 524                         break;
 525                 if (!(nr_pages % m))
 526                         printk("\b\b\b\b%3d%%", nr_pages / m);
 527                 nr_pages++;
 528         }
 529         err2 = wait_on_bio_chain(&bio);
 530         do_gettimeofday(&stop);
 531         if (!error)
 532                 error = err2;
 533         if (!error) {
 534                 printk("\b\b\b\bdone\n");
 535                 snapshot_write_finalize(snapshot);
 536                 if (!snapshot_image_loaded(snapshot))
 537                         error = -ENODATA;
 538         }
 539         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 540         return error;
 541 }
 542
 543 int swsusp_read(void)
 544 {
 545         int error;
 546         struct swap_map_handle handle;
 547         struct snapshot_handle snapshot;
 548         struct swsusp_info *header;
 549
 550         if (IS_ERR(resume_bdev)) {
 551                 pr_debug("swsusp: block device not initialised\n");
 552                 return PTR_ERR(resume_bdev);
 553         }
 554
 555         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 556         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 557         if (error < PAGE_SIZE)
 558                 return error < 0 ? error : -EFAULT;
 559         header = (struct swsusp_info *)data_of(snapshot);
 560         error = get_swap_reader(&handle, swsusp_header->image);
 561         if (!error)
 562                 error = swap_read_page(&handle, header, NULL);
 563         if (!error)
 564                 error = load_image(&handle, &snapshot, header->pages - 1);
 565         release_swap_reader(&handle);
 566
 567         blkdev_put(resume_bdev);
 568
 569         if (!error)
 570                 pr_debug("swsusp: Reading resume file was successful\n");
 571         else
 572                 pr_debug("swsusp: Error %d resuming\n", error);
 573         return error;
 574 }
 575
 576 /**
 577  *      swsusp_check - Check for swsusp signature in the resume device
 578  */
 579
 580 int swsusp_check(void)
 581 {
 582         int error;
 583
 584         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 585         if (!IS_ERR(resume_bdev)) {
 586                 set_blocksize(resume_bdev, PAGE_SIZE);
 587                 memset(swsusp_header, 0, sizeof(PAGE_SIZE));
 588                 error = bio_read_page(swsusp_resume_block,
 589                                         swsusp_header, NULL);
 590                 if (error)
 591                         return error;
 592
 593                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 594                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 595                         /* Reset swap signature now */
 596                         error = bio_write_page(swsusp_resume_block,
 597                                                 swsusp_header, NULL);
 598                 } else {
 599                         return -EINVAL;
 600                 }
 601                 if (error)
 602                         blkdev_put(resume_bdev);
 603                 else
 604                         pr_debug("swsusp: Signature found, resuming\n");
 605         } else {
 606                 error = PTR_ERR(resume_bdev);
 607         }
 608
 609         if (error)
 610                 pr_debug("swsusp: Error %d check for resume file\n", error);
 611
 612         return error;
 613 }
 614
 615 /**
 616  *      swsusp_close - close swap device.
 617  */
 618
 619 void swsusp_close(void)
 620 {
 621         if (IS_ERR(resume_bdev)) {
 622                 pr_debug("swsusp: block device not initialised\n");
 623                 return;
 624         }
 625
 626         blkdev_put(resume_bdev);
 627 }
 628
 629 static int swsusp_header_init(void)
 630 {
 631         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
 632         if (!swsusp_header)
 633                 panic("Could not allocate memory for swsusp_header\n");
 634         return 0;
 635 }
 636
 637 core_initcall(swsusp_header_init);