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/delay.h>
  17 #include <linux/bitops.h>
  18 #include <linux/genhd.h>
  19 #include <linux/device.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/bio.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/swap.h>
  24 #include <linux/swapops.h>
  25 #include <linux/pm.h>
  26
  27 #include "power.h"
  28
  29 #define SWSUSP_SIG      "S1SUSPEND"
  30
  31 struct swsusp_header {
  32         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
  33         sector_t image;
  34         unsigned int flags;     /* Flags to pass to the "boot" kernel */
  35         char    orig_sig[10];
  36         char    sig[10];
  37 } __attribute__((packed));
  38
  39 static struct swsusp_header *swsusp_header;
  40
  41 /*
  42  * General things
  43  */
  44
  45 static unsigned short root_swap = 0xffff;
  46 static struct block_device *resume_bdev;
  47
  48 /**
  49  *      submit - submit BIO request.
  50  *      @rw:    READ or WRITE.
  51  *      @off    physical offset of page.
  52  *      @page:  page we're reading or writing.
  53  *      @bio_chain: list of pending biod (for async reading)
  54  *
  55  *      Straight from the textbook - allocate and initialize the bio.
  56  *      If we're reading, make sure the page is marked as dirty.
  57  *      Then submit it and, if @bio_chain == NULL, wait.
  58  */
  59 static int submit(int rw, pgoff_t page_off, struct page *page,
  60                         struct bio **bio_chain)
  61 {
  62         const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
  63         struct bio *bio;
  64
  65         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
  66         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
  67         bio->bi_bdev = resume_bdev;
  68         bio->bi_end_io = end_swap_bio_read;
  69
  70         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
  71                 printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
  72                         page_off);
  73                 bio_put(bio);
  74                 return -EFAULT;
  75         }
  76
  77         lock_page(page);
  78         bio_get(bio);
  79
  80         if (bio_chain == NULL) {
  81                 submit_bio(bio_rw, bio);
  82                 wait_on_page_locked(page);
  83                 if (rw == READ)
  84                         bio_set_pages_dirty(bio);
  85                 bio_put(bio);
  86         } else {
  87                 if (rw == READ)
  88                         get_page(page); /* These pages are freed later */
  89                 bio->bi_private = *bio_chain;
  90                 *bio_chain = bio;
  91                 submit_bio(bio_rw, bio);
  92         }
  93         return 0;
  94 }
  95
  96 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
  97 {
  98         return submit(READ, page_off, virt_to_page(addr), bio_chain);
  99 }
 100
 101 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
 102 {
 103         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
 104 }
 105
 106 static int wait_on_bio_chain(struct bio **bio_chain)
 107 {
 108         struct bio *bio;
 109         struct bio *next_bio;
 110         int ret = 0;
 111
 112         if (bio_chain == NULL)
 113                 return 0;
 114
 115         bio = *bio_chain;
 116         if (bio == NULL)
 117                 return 0;
 118         while (bio) {
 119                 struct page *page;
 120
 121                 next_bio = bio->bi_private;
 122                 page = bio->bi_io_vec[0].bv_page;
 123                 wait_on_page_locked(page);
 124                 if (!PageUptodate(page) || PageError(page))
 125                         ret = -EIO;
 126                 put_page(page);
 127                 bio_put(bio);
 128                 bio = next_bio;
 129         }
 130         *bio_chain = NULL;
 131         return ret;
 132 }
 133
 134 /*
 135  * Saving part
 136  */
 137
 138 static int mark_swapfiles(sector_t start, unsigned int flags)
 139 {
 140         int error;
 141
 142         bio_read_page(swsusp_resume_block, swsusp_header, NULL);
 143         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 144             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 145                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
 146                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
 147                 swsusp_header->image = start;
 148                 swsusp_header->flags = flags;
 149                 error = bio_write_page(swsusp_resume_block,
 150                                         swsusp_header, NULL);
 151         } else {
 152                 printk(KERN_ERR "PM: Swap header not found!\n");
 153                 error = -ENODEV;
 154         }
 155         return error;
 156 }
 157
 158 /**
 159  *      swsusp_swap_check - check if the resume device is a swap device
 160  *      and get its index (if so)
 161  */
 162
 163 static int swsusp_swap_check(void) /* This is called before saving image */
 164 {
 165         int res;
 166
 167         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 168                         &resume_bdev);
 169         if (res < 0)
 170                 return res;
 171
 172         root_swap = res;
 173         res = blkdev_get(resume_bdev, FMODE_WRITE);
 174         if (res)
 175                 return res;
 176
 177         res = set_blocksize(resume_bdev, PAGE_SIZE);
 178         if (res < 0)
 179                 blkdev_put(resume_bdev, FMODE_WRITE);
 180
 181         return res;
 182 }
 183
 184 /**
 185  *      write_page - Write one page to given swap location.
 186  *      @buf:           Address we're writing.
 187  *      @offset:        Offset of the swap page we're writing to.
 188  *      @bio_chain:     Link the next write BIO here
 189  */
 190
 191 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 192 {
 193         void *src;
 194
 195         if (!offset)
 196                 return -ENOSPC;
 197
 198         if (bio_chain) {
 199                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 200                 if (src) {
 201                         memcpy(src, buf, PAGE_SIZE);
 202                 } else {
 203                         WARN_ON_ONCE(1);
 204                         bio_chain = NULL;       /* Go synchronous */
 205                         src = buf;
 206                 }
 207         } else {
 208                 src = buf;
 209         }
 210         return bio_write_page(offset, src, bio_chain);
 211 }
 212
 213 /*
 214  *      The swap map is a data structure used for keeping track of each page
 215  *      written to a swap partition.  It consists of many swap_map_page
 216  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 217  *      These structures are stored on the swap and linked together with the
 218  *      help of the .next_swap member.
 219  *
 220  *      The swap map is created during suspend.  The swap map pages are
 221  *      allocated and populated one at a time, so we only need one memory
 222  *      page to set up the entire structure.
 223  *
 224  *      During resume we also only need to use one swap_map_page structure
 225  *      at a time.
 226  */
 227
 228 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 229
 230 struct swap_map_page {
 231         sector_t entries[MAP_PAGE_ENTRIES];
 232         sector_t next_swap;
 233 };
 234
 235 /**
 236  *      The swap_map_handle structure is used for handling swap in
 237  *      a file-alike way
 238  */
 239
 240 struct swap_map_handle {
 241         struct swap_map_page *cur;
 242         sector_t cur_swap;
 243         unsigned int k;
 244 };
 245
 246 static void release_swap_writer(struct swap_map_handle *handle)
 247 {
 248         if (handle->cur)
 249                 free_page((unsigned long)handle->cur);
 250         handle->cur = NULL;
 251 }
 252
 253 static int get_swap_writer(struct swap_map_handle *handle)
 254 {
 255         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 256         if (!handle->cur)
 257                 return -ENOMEM;
 258         handle->cur_swap = alloc_swapdev_block(root_swap);
 259         if (!handle->cur_swap) {
 260                 release_swap_writer(handle);
 261                 return -ENOSPC;
 262         }
 263         handle->k = 0;
 264         return 0;
 265 }
 266
 267 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 268                                 struct bio **bio_chain)
 269 {
 270         int error = 0;
 271         sector_t offset;
 272
 273         if (!handle->cur)
 274                 return -EINVAL;
 275         offset = alloc_swapdev_block(root_swap);
 276         error = write_page(buf, offset, bio_chain);
 277         if (error)
 278                 return error;
 279         handle->cur->entries[handle->k++] = offset;
 280         if (handle->k >= MAP_PAGE_ENTRIES) {
 281                 error = wait_on_bio_chain(bio_chain);
 282                 if (error)
 283                         goto out;
 284                 offset = alloc_swapdev_block(root_swap);
 285                 if (!offset)
 286                         return -ENOSPC;
 287                 handle->cur->next_swap = offset;
 288                 error = write_page(handle->cur, handle->cur_swap, NULL);
 289                 if (error)
 290                         goto out;
 291                 memset(handle->cur, 0, PAGE_SIZE);
 292                 handle->cur_swap = offset;
 293                 handle->k = 0;
 294         }
 295  out:
 296         return error;
 297 }
 298
 299 static int flush_swap_writer(struct swap_map_handle *handle)
 300 {
 301         if (handle->cur && handle->cur_swap)
 302                 return write_page(handle->cur, handle->cur_swap, NULL);
 303         else
 304                 return -EINVAL;
 305 }
 306
 307 /**
 308  *      save_image - save the suspend image data
 309  */
 310
 311 static int save_image(struct swap_map_handle *handle,
 312                       struct snapshot_handle *snapshot,
 313                       unsigned int nr_to_write)
 314 {
 315         unsigned int m;
 316         int ret;
 317         int error = 0;
 318         int nr_pages;
 319         int err2;
 320         struct bio *bio;
 321         struct timeval start;
 322         struct timeval stop;
 323
 324         printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
 325                 nr_to_write);
 326         m = nr_to_write / 100;
 327         if (!m)
 328                 m = 1;
 329         nr_pages = 0;
 330         bio = NULL;
 331         do_gettimeofday(&start);
 332         do {
 333                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 334                 if (ret > 0) {
 335                         error = swap_write_page(handle, data_of(*snapshot),
 336                                                 &bio);
 337                         if (error)
 338                                 break;
 339                         if (!(nr_pages % m))
 340                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 341                         nr_pages++;
 342                 }
 343         } while (ret > 0);
 344         err2 = wait_on_bio_chain(&bio);
 345         do_gettimeofday(&stop);
 346         if (!error)
 347                 error = err2;
 348         if (!error)
 349                 printk("\b\b\b\bdone\n");
 350         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
 351         return error;
 352 }
 353
 354 /**
 355  *      enough_swap - Make sure we have enough swap to save the image.
 356  *
 357  *      Returns TRUE or FALSE after checking the total amount of swap
 358  *      space avaiable from the resume partition.
 359  */
 360
 361 static int enough_swap(unsigned int nr_pages)
 362 {
 363         unsigned int free_swap = count_swap_pages(root_swap, 1);
 364
 365         pr_debug("PM: Free swap pages: %u\n", free_swap);
 366         return free_swap > nr_pages + PAGES_FOR_IO;
 367 }
 368
 369 /**
 370  *      swsusp_write - Write entire image and metadata.
 371  *      @flags: flags to pass to the "boot" kernel in the image header
 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(unsigned int flags)
 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 "PM: 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 "PM: 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(KERN_INFO "PM: S");
 418                         error = mark_swapfiles(start, flags);
 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(FMODE_WRITE);
 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(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
 508                 nr_to_read);
 509         m = nr_to_read / 100;
 510         if (!m)
 511                 m = 1;
 512         nr_pages = 0;
 513         bio = NULL;
 514         do_gettimeofday(&start);
 515         for ( ; ; ) {
 516                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 517                 if (error <= 0)
 518                         break;
 519                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 520                 if (error)
 521                         break;
 522                 if (snapshot->sync_read)
 523                         error = wait_on_bio_chain(&bio);
 524                 if (error)
 525                         break;
 526                 if (!(nr_pages % m))
 527                         printk("\b\b\b\b%3d%%", nr_pages / m);
 528                 nr_pages++;
 529         }
 530         err2 = wait_on_bio_chain(&bio);
 531         do_gettimeofday(&stop);
 532         if (!error)
 533                 error = err2;
 534         if (!error) {
 535                 printk("\b\b\b\bdone\n");
 536                 snapshot_write_finalize(snapshot);
 537                 if (!snapshot_image_loaded(snapshot))
 538                         error = -ENODATA;
 539         }
 540         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
 541         return error;
 542 }
 543
 544 /**
 545  *      swsusp_read - read the hibernation image.
 546  *      @flags_p: flags passed by the "frozen" kernel in the image header should
 547  *                be written into this memeory location
 548  */
 549
 550 int swsusp_read(unsigned int *flags_p)
 551 {
 552         int error;
 553         struct swap_map_handle handle;
 554         struct snapshot_handle snapshot;
 555         struct swsusp_info *header;
 556
 557         *flags_p = swsusp_header->flags;
 558         if (IS_ERR(resume_bdev)) {
 559                 pr_debug("PM: Image device not initialised\n");
 560                 return PTR_ERR(resume_bdev);
 561         }
 562
 563         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 564         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 565         if (error < PAGE_SIZE)
 566                 return error < 0 ? error : -EFAULT;
 567         header = (struct swsusp_info *)data_of(snapshot);
 568         error = get_swap_reader(&handle, swsusp_header->image);
 569         if (!error)
 570                 error = swap_read_page(&handle, header, NULL);
 571         if (!error)
 572                 error = load_image(&handle, &snapshot, header->pages - 1);
 573         release_swap_reader(&handle);
 574
 575         blkdev_put(resume_bdev, FMODE_READ);
 576
 577         if (!error)
 578                 pr_debug("PM: Image successfully loaded\n");
 579         else
 580                 pr_debug("PM: Error %d resuming\n", error);
 581         return error;
 582 }
 583
 584 /**
 585  *      swsusp_check - Check for swsusp signature in the resume device
 586  */
 587
 588 int swsusp_check(void)
 589 {
 590         int error;
 591
 592         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 593         if (!IS_ERR(resume_bdev)) {
 594                 set_blocksize(resume_bdev, PAGE_SIZE);
 595                 memset(swsusp_header, 0, PAGE_SIZE);
 596                 error = bio_read_page(swsusp_resume_block,
 597                                         swsusp_header, NULL);
 598                 if (error)
 599                         return error;
 600
 601                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 602                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 603                         /* Reset swap signature now */
 604                         error = bio_write_page(swsusp_resume_block,
 605                                                 swsusp_header, NULL);
 606                 } else {
 607                         return -EINVAL;
 608                 }
 609                 if (error)
 610                         blkdev_put(resume_bdev, FMODE_READ);
 611                 else
 612                         pr_debug("PM: Signature found, resuming\n");
 613         } else {
 614                 error = PTR_ERR(resume_bdev);
 615         }
 616
 617         if (error)
 618                 pr_debug("PM: Error %d checking image file\n", error);
 619
 620         return error;
 621 }
 622
 623 /**
 624  *      swsusp_close - close swap device.
 625  */
 626
 627 void swsusp_close(fmode_t mode)
 628 {
 629         if (IS_ERR(resume_bdev)) {
 630                 pr_debug("PM: Image device not initialised\n");
 631                 return;
 632         }
 633
 634         blkdev_put(resume_bdev, mode);
 635 }
 636
 637 static int swsusp_header_init(void)
 638 {
 639         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
 640         if (!swsusp_header)
 641                 panic("Could not allocate memory for swsusp_header\n");
 642         return 0;
 643 }
 644
 645 core_initcall(swsusp_header_init);