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) - sizeof(int)];
  37         sector_t image;
  38         unsigned int flags;     /* Flags to pass to the "boot" kernel */
  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, unsigned int flags)
 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                 swsusp_header->flags = flags;
 153                 error = bio_write_page(swsusp_resume_block,
 154                                         swsusp_header, NULL);
 155         } else {
 156                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 157                 error = -ENODEV;
 158         }
 159         return error;
 160 }
 161
 162 /**
 163  *      swsusp_swap_check - check if the resume device is a swap device
 164  *      and get its index (if so)
 165  */
 166
 167 static int swsusp_swap_check(void) /* This is called before saving image */
 168 {
 169         int res;
 170
 171         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 172                         &resume_bdev);
 173         if (res < 0)
 174                 return res;
 175
 176         root_swap = res;
 177         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
 178         if (res)
 179                 return res;
 180
 181         res = set_blocksize(resume_bdev, PAGE_SIZE);
 182         if (res < 0)
 183                 blkdev_put(resume_bdev);
 184
 185         return res;
 186 }
 187
 188 /**
 189  *      write_page - Write one page to given swap location.
 190  *      @buf:           Address we're writing.
 191  *      @offset:        Offset of the swap page we're writing to.
 192  *      @bio_chain:     Link the next write BIO here
 193  */
 194
 195 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 196 {
 197         void *src;
 198
 199         if (!offset)
 200                 return -ENOSPC;
 201
 202         if (bio_chain) {
 203                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 204                 if (src) {
 205                         memcpy(src, buf, PAGE_SIZE);
 206                 } else {
 207                         WARN_ON_ONCE(1);
 208                         bio_chain = NULL;       /* Go synchronous */
 209                         src = buf;
 210                 }
 211         } else {
 212                 src = buf;
 213         }
 214         return bio_write_page(offset, src, bio_chain);
 215 }
 216
 217 /*
 218  *      The swap map is a data structure used for keeping track of each page
 219  *      written to a swap partition.  It consists of many swap_map_page
 220  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 221  *      These structures are stored on the swap and linked together with the
 222  *      help of the .next_swap member.
 223  *
 224  *      The swap map is created during suspend.  The swap map pages are
 225  *      allocated and populated one at a time, so we only need one memory
 226  *      page to set up the entire structure.
 227  *
 228  *      During resume we also only need to use one swap_map_page structure
 229  *      at a time.
 230  */
 231
 232 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 233
 234 struct swap_map_page {
 235         sector_t entries[MAP_PAGE_ENTRIES];
 236         sector_t next_swap;
 237 };
 238
 239 /**
 240  *      The swap_map_handle structure is used for handling swap in
 241  *      a file-alike way
 242  */
 243
 244 struct swap_map_handle {
 245         struct swap_map_page *cur;
 246         sector_t cur_swap;
 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 }
 256
 257 static int get_swap_writer(struct swap_map_handle *handle)
 258 {
 259         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 260         if (!handle->cur)
 261                 return -ENOMEM;
 262         handle->cur_swap = alloc_swapdev_block(root_swap);
 263         if (!handle->cur_swap) {
 264                 release_swap_writer(handle);
 265                 return -ENOSPC;
 266         }
 267         handle->k = 0;
 268         return 0;
 269 }
 270
 271 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 272                                 struct bio **bio_chain)
 273 {
 274         int error = 0;
 275         sector_t offset;
 276
 277         if (!handle->cur)
 278                 return -EINVAL;
 279         offset = alloc_swapdev_block(root_swap);
 280         error = write_page(buf, offset, bio_chain);
 281         if (error)
 282                 return error;
 283         handle->cur->entries[handle->k++] = offset;
 284         if (handle->k >= MAP_PAGE_ENTRIES) {
 285                 error = wait_on_bio_chain(bio_chain);
 286                 if (error)
 287                         goto out;
 288                 offset = alloc_swapdev_block(root_swap);
 289                 if (!offset)
 290                         return -ENOSPC;
 291                 handle->cur->next_swap = offset;
 292                 error = write_page(handle->cur, handle->cur_swap, NULL);
 293                 if (error)
 294                         goto out;
 295                 memset(handle->cur, 0, PAGE_SIZE);
 296                 handle->cur_swap = offset;
 297                 handle->k = 0;
 298         }
 299  out:
 300         return error;
 301 }
 302
 303 static int flush_swap_writer(struct swap_map_handle *handle)
 304 {
 305         if (handle->cur && handle->cur_swap)
 306                 return write_page(handle->cur, handle->cur_swap, NULL);
 307         else
 308                 return -EINVAL;
 309 }
 310
 311 /**
 312  *      save_image - save the suspend image data
 313  */
 314
 315 static int save_image(struct swap_map_handle *handle,
 316                       struct snapshot_handle *snapshot,
 317                       unsigned int nr_to_write)
 318 {
 319         unsigned int m;
 320         int ret;
 321         int error = 0;
 322         int nr_pages;
 323         int err2;
 324         struct bio *bio;
 325         struct timeval start;
 326         struct timeval stop;
 327
 328         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 329         m = nr_to_write / 100;
 330         if (!m)
 331                 m = 1;
 332         nr_pages = 0;
 333         bio = NULL;
 334         do_gettimeofday(&start);
 335         do {
 336                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 337                 if (ret > 0) {
 338                         error = swap_write_page(handle, data_of(*snapshot),
 339                                                 &bio);
 340                         if (error)
 341                                 break;
 342                         if (!(nr_pages % m))
 343                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 344                         nr_pages++;
 345                 }
 346         } while (ret > 0);
 347         err2 = wait_on_bio_chain(&bio);
 348         do_gettimeofday(&stop);
 349         if (!error)
 350                 error = err2;
 351         if (!error)
 352                 printk("\b\b\b\bdone\n");
 353         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 354         return error;
 355 }
 356
 357 /**
 358  *      enough_swap - Make sure we have enough swap to save the image.
 359  *
 360  *      Returns TRUE or FALSE after checking the total amount of swap
 361  *      space avaiable from the resume partition.
 362  */
 363
 364 static int enough_swap(unsigned int nr_pages)
 365 {
 366         unsigned int free_swap = count_swap_pages(root_swap, 1);
 367
 368         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 369         return free_swap > nr_pages + PAGES_FOR_IO;
 370 }
 371
 372 /**
 373  *      swsusp_write - Write entire image and metadata.
 374  *      @flags: flags to pass to the "boot" kernel in the image header
 375  *
 376  *      It is important _NOT_ to umount filesystems at this point. We want
 377  *      them synced (in case something goes wrong) but we DO not want to mark
 378  *      filesystem clean: it is not. (And it does not matter, if we resume
 379  *      correctly, we'll mark system clean, anyway.)
 380  */
 381
 382 int swsusp_write(unsigned int flags)
 383 {
 384         struct swap_map_handle handle;
 385         struct snapshot_handle snapshot;
 386         struct swsusp_info *header;
 387         int error;
 388
 389         error = swsusp_swap_check();
 390         if (error) {
 391                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 392                                 "swapon -a.\n");
 393                 return error;
 394         }
 395         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 396         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 397         if (error < PAGE_SIZE) {
 398                 if (error >= 0)
 399                         error = -EFAULT;
 400
 401                 goto out;
 402         }
 403         header = (struct swsusp_info *)data_of(snapshot);
 404         if (!enough_swap(header->pages)) {
 405                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 406                 error = -ENOSPC;
 407                 goto out;
 408         }
 409         error = get_swap_writer(&handle);
 410         if (!error) {
 411                 sector_t start = handle.cur_swap;
 412
 413                 error = swap_write_page(&handle, header, NULL);
 414                 if (!error)
 415                         error = save_image(&handle, &snapshot,
 416                                         header->pages - 1);
 417
 418                 if (!error) {
 419                         flush_swap_writer(&handle);
 420                         printk("S");
 421                         error = mark_swapfiles(start, flags);
 422                         printk("|\n");
 423                 }
 424         }
 425         if (error)
 426                 free_all_swap_pages(root_swap);
 427
 428         release_swap_writer(&handle);
 429  out:
 430         swsusp_close();
 431         return error;
 432 }
 433
 434 /**
 435  *      The following functions allow us to read data using a swap map
 436  *      in a file-alike way
 437  */
 438
 439 static void release_swap_reader(struct swap_map_handle *handle)
 440 {
 441         if (handle->cur)
 442                 free_page((unsigned long)handle->cur);
 443         handle->cur = NULL;
 444 }
 445
 446 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 447 {
 448         int error;
 449
 450         if (!start)
 451                 return -EINVAL;
 452
 453         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 454         if (!handle->cur)
 455                 return -ENOMEM;
 456
 457         error = bio_read_page(start, handle->cur, NULL);
 458         if (error) {
 459                 release_swap_reader(handle);
 460                 return error;
 461         }
 462         handle->k = 0;
 463         return 0;
 464 }
 465
 466 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 467                                 struct bio **bio_chain)
 468 {
 469         sector_t offset;
 470         int error;
 471
 472         if (!handle->cur)
 473                 return -EINVAL;
 474         offset = handle->cur->entries[handle->k];
 475         if (!offset)
 476                 return -EFAULT;
 477         error = bio_read_page(offset, buf, bio_chain);
 478         if (error)
 479                 return error;
 480         if (++handle->k >= MAP_PAGE_ENTRIES) {
 481                 error = wait_on_bio_chain(bio_chain);
 482                 handle->k = 0;
 483                 offset = handle->cur->next_swap;
 484                 if (!offset)
 485                         release_swap_reader(handle);
 486                 else if (!error)
 487                         error = bio_read_page(offset, handle->cur, NULL);
 488         }
 489         return error;
 490 }
 491
 492 /**
 493  *      load_image - load the image using the swap map handle
 494  *      @handle and the snapshot handle @snapshot
 495  *      (assume there are @nr_pages pages to load)
 496  */
 497
 498 static int load_image(struct swap_map_handle *handle,
 499                       struct snapshot_handle *snapshot,
 500                       unsigned int nr_to_read)
 501 {
 502         unsigned int m;
 503         int error = 0;
 504         struct timeval start;
 505         struct timeval stop;
 506         struct bio *bio;
 507         int err2;
 508         unsigned nr_pages;
 509
 510         printk("Loading image data pages (%u pages) ...     ", 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("swsusp: block 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);
 578
 579         if (!error)
 580                 pr_debug("swsusp: Reading resume file was successful\n");
 581         else
 582                 pr_debug("swsusp: 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);
 613                 else
 614                         pr_debug("swsusp: Signature found, resuming\n");
 615         } else {
 616                 error = PTR_ERR(resume_bdev);
 617         }
 618
 619         if (error)
 620                 pr_debug("swsusp: Error %d check for resume 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("swsusp: block device not initialised\n");
 633                 return;
 634         }
 635
 636         blkdev_put(resume_bdev);
 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);