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         struct bio *bio;
  64
  65         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  66         if (!bio)
  67                 return -ENOMEM;
  68         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  69         bio->bi_bdev = resume_bdev;
  70         bio->bi_end_io = end_swap_bio_read;
  71
  72         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  73                 printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
  74                         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, unsigned int flags)
 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                 swsusp_header->flags = flags;
 151                 error = bio_write_page(swsusp_resume_block,
 152                                         swsusp_header, NULL);
 153         } else {
 154                 printk(KERN_ERR "PM: 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, FMODE_WRITE);
 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(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
 327                 nr_to_write);
 328         m = nr_to_write / 100;
 329         if (!m)
 330                 m = 1;
 331         nr_pages = 0;
 332         bio = NULL;
 333         do_gettimeofday(&start);
 334         do {
 335                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 336                 if (ret > 0) {
 337                         error = swap_write_page(handle, data_of(*snapshot),
 338                                                 &bio);
 339                         if (error)
 340                                 break;
 341                         if (!(nr_pages % m))
 342                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 343                         nr_pages++;
 344                 }
 345         } while (ret > 0);
 346         err2 = wait_on_bio_chain(&bio);
 347         do_gettimeofday(&stop);
 348         if (!error)
 349                 error = err2;
 350         if (!error)
 351                 printk("\b\b\b\bdone\n");
 352         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 353         return error;
 354 }
 355
 356 /**
 357  *      enough_swap - Make sure we have enough swap to save the image.
 358  *
 359  *      Returns TRUE or FALSE after checking the total amount of swap
 360  *      space avaiable from the resume partition.
 361  */
 362
 363 static int enough_swap(unsigned int nr_pages)
 364 {
 365         unsigned int free_swap = count_swap_pages(root_swap, 1);
 366
 367         pr_debug("PM: Free swap pages: %u\n", free_swap);
 368         return free_swap > nr_pages + PAGES_FOR_IO;
 369 }
 370
 371 /**
 372  *      swsusp_write - Write entire image and metadata.
 373  *      @flags: flags to pass to the "boot" kernel in the image header
 374  *
 375  *      It is important _NOT_ to umount filesystems at this point. We want
 376  *      them synced (in case something goes wrong) but we DO not want to mark
 377  *      filesystem clean: it is not. (And it does not matter, if we resume
 378  *      correctly, we'll mark system clean, anyway.)
 379  */
 380
 381 int swsusp_write(unsigned int flags)
 382 {
 383         struct swap_map_handle handle;
 384         struct snapshot_handle snapshot;
 385         struct swsusp_info *header;
 386         int error;
 387
 388         error = swsusp_swap_check();
 389         if (error) {
 390                 printk(KERN_ERR "PM: Cannot find swap device, try "
 391                                 "swapon -a.\n");
 392                 return error;
 393         }
 394         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 395         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 396         if (error < PAGE_SIZE) {
 397                 if (error >= 0)
 398                         error = -EFAULT;
 399
 400                 goto out;
 401         }
 402         header = (struct swsusp_info *)data_of(snapshot);
 403         if (!enough_swap(header->pages)) {
 404                 printk(KERN_ERR "PM: Not enough free swap\n");
 405                 error = -ENOSPC;
 406                 goto out;
 407         }
 408         error = get_swap_writer(&handle);
 409         if (!error) {
 410                 sector_t start = handle.cur_swap;
 411
 412                 error = swap_write_page(&handle, header, NULL);
 413                 if (!error)
 414                         error = save_image(&handle, &snapshot,
 415                                         header->pages - 1);
 416
 417                 if (!error) {
 418                         flush_swap_writer(&handle);
 419                         printk(KERN_INFO "PM: S");
 420                         error = mark_swapfiles(start, flags);
 421                         printk("|\n");
 422                 }
 423         }
 424         if (error)
 425                 free_all_swap_pages(root_swap);
 426
 427         release_swap_writer(&handle);
 428  out:
 429         swsusp_close();
 430         return error;
 431 }
 432
 433 /**
 434  *      The following functions allow us to read data using a swap map
 435  *      in a file-alike way
 436  */
 437
 438 static void release_swap_reader(struct swap_map_handle *handle)
 439 {
 440         if (handle->cur)
 441                 free_page((unsigned long)handle->cur);
 442         handle->cur = NULL;
 443 }
 444
 445 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 446 {
 447         int error;
 448
 449         if (!start)
 450                 return -EINVAL;
 451
 452         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 453         if (!handle->cur)
 454                 return -ENOMEM;
 455
 456         error = bio_read_page(start, handle->cur, NULL);
 457         if (error) {
 458                 release_swap_reader(handle);
 459                 return error;
 460         }
 461         handle->k = 0;
 462         return 0;
 463 }
 464
 465 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 466                                 struct bio **bio_chain)
 467 {
 468         sector_t offset;
 469         int error;
 470
 471         if (!handle->cur)
 472                 return -EINVAL;
 473         offset = handle->cur->entries[handle->k];
 474         if (!offset)
 475                 return -EFAULT;
 476         error = bio_read_page(offset, buf, bio_chain);
 477         if (error)
 478                 return error;
 479         if (++handle->k >= MAP_PAGE_ENTRIES) {
 480                 error = wait_on_bio_chain(bio_chain);
 481                 handle->k = 0;
 482                 offset = handle->cur->next_swap;
 483                 if (!offset)
 484                         release_swap_reader(handle);
 485                 else if (!error)
 486                         error = bio_read_page(offset, handle->cur, NULL);
 487         }
 488         return error;
 489 }
 490
 491 /**
 492  *      load_image - load the image using the swap map handle
 493  *      @handle and the snapshot handle @snapshot
 494  *      (assume there are @nr_pages pages to load)
 495  */
 496
 497 static int load_image(struct swap_map_handle *handle,
 498                       struct snapshot_handle *snapshot,
 499                       unsigned int nr_to_read)
 500 {
 501         unsigned int m;
 502         int error = 0;
 503         struct timeval start;
 504         struct timeval stop;
 505         struct bio *bio;
 506         int err2;
 507         unsigned nr_pages;
 508
 509         printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
 510                 nr_to_read);
 511         m = nr_to_read / 100;
 512         if (!m)
 513                 m = 1;
 514         nr_pages = 0;
 515         bio = NULL;
 516         do_gettimeofday(&start);
 517         for ( ; ; ) {
 518                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 519                 if (error <= 0)
 520                         break;
 521                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 522                 if (error)
 523                         break;
 524                 if (snapshot->sync_read)
 525                         error = wait_on_bio_chain(&bio);
 526                 if (error)
 527                         break;
 528                 if (!(nr_pages % m))
 529                         printk("\b\b\b\b%3d%%", nr_pages / m);
 530                 nr_pages++;
 531         }
 532         err2 = wait_on_bio_chain(&bio);
 533         do_gettimeofday(&stop);
 534         if (!error)
 535                 error = err2;
 536         if (!error) {
 537                 printk("\b\b\b\bdone\n");
 538                 snapshot_write_finalize(snapshot);
 539                 if (!snapshot_image_loaded(snapshot))
 540                         error = -ENODATA;
 541         }
 542         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 543         return error;
 544 }
 545
 546 /**
 547  *      swsusp_read - read the hibernation image.
 548  *      @flags_p: flags passed by the "frozen" kernel in the image header should
 549  *                be written into this memeory location
 550  */
 551
 552 int swsusp_read(unsigned int *flags_p)
 553 {
 554         int error;
 555         struct swap_map_handle handle;
 556         struct snapshot_handle snapshot;
 557         struct swsusp_info *header;
 558
 559         *flags_p = swsusp_header->flags;
 560         if (IS_ERR(resume_bdev)) {
 561                 pr_debug("PM: Image device not initialised\n");
 562                 return PTR_ERR(resume_bdev);
 563         }
 564
 565         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 566         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 567         if (error < PAGE_SIZE)
 568                 return error < 0 ? error : -EFAULT;
 569         header = (struct swsusp_info *)data_of(snapshot);
 570         error = get_swap_reader(&handle, swsusp_header->image);
 571         if (!error)
 572                 error = swap_read_page(&handle, header, NULL);
 573         if (!error)
 574                 error = load_image(&handle, &snapshot, header->pages - 1);
 575         release_swap_reader(&handle);
 576
 577         blkdev_put(resume_bdev, FMODE_READ);
 578
 579         if (!error)
 580                 pr_debug("PM: Image successfully loaded\n");
 581         else
 582                 pr_debug("PM: Error %d resuming\n", error);
 583         return error;
 584 }
 585
 586 /**
 587  *      swsusp_check - Check for swsusp signature in the resume device
 588  */
 589
 590 int swsusp_check(void)
 591 {
 592         int error;
 593
 594         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 595         if (!IS_ERR(resume_bdev)) {
 596                 set_blocksize(resume_bdev, PAGE_SIZE);
 597                 memset(swsusp_header, 0, PAGE_SIZE);
 598                 error = bio_read_page(swsusp_resume_block,
 599                                         swsusp_header, NULL);
 600                 if (error)
 601                         return error;
 602
 603                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 604                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 605                         /* Reset swap signature now */
 606                         error = bio_write_page(swsusp_resume_block,
 607                                                 swsusp_header, NULL);
 608                 } else {
 609                         return -EINVAL;
 610                 }
 611                 if (error)
 612                         blkdev_put(resume_bdev, FMODE_READ);
 613                 else
 614                         pr_debug("PM: Signature found, resuming\n");
 615         } else {
 616                 error = PTR_ERR(resume_bdev);
 617         }
 618
 619         if (error)
 620                 pr_debug("PM: Error %d checking image file\n", error);
 621
 622         return error;
 623 }
 624
 625 /**
 626  *      swsusp_close - close swap device.
 627  */
 628
 629 void swsusp_close(void)
 630 {
 631         if (IS_ERR(resume_bdev)) {
 632                 pr_debug("PM: Image device not initialised\n");
 633                 return;
 634         }
 635
 636         blkdev_put(resume_bdev, 0); /* move up */
 637 }
 638
 639 static int swsusp_header_init(void)
 640 {
 641         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
 642         if (!swsusp_header)
 643                 panic("Could not allocate memory for swsusp_header\n");
 644         return 0;
 645 }
 646
 647 core_initcall(swsusp_header_init);