SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #define SWSUSP_SIG      "S1SUSPEND"
  32
  33 struct swsusp_header {
  34         char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
  35         sector_t image;
  36         unsigned int flags;     /* Flags to pass to the "boot" kernel */
  37         char    orig_sig[10];
  38         char    sig[10];
  39 } __attribute__((packed));
  40
  41 static struct swsusp_header *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, 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 "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  *      @flags: flags to pass to the "boot" kernel in the image header
 373  *
 374  *      It is important _NOT_ to umount filesystems at this point. We want
 375  *      them synced (in case something goes wrong) but we DO not want to mark
 376  *      filesystem clean: it is not. (And it does not matter, if we resume
 377  *      correctly, we'll mark system clean, anyway.)
 378  */
 379
 380 int swsusp_write(unsigned int flags)
 381 {
 382         struct swap_map_handle handle;
 383         struct snapshot_handle snapshot;
 384         struct swsusp_info *header;
 385         int error;
 386
 387         error = swsusp_swap_check();
 388         if (error) {
 389                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 390                                 "swapon -a.\n");
 391                 return error;
 392         }
 393         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 394         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 395         if (error < PAGE_SIZE) {
 396                 if (error >= 0)
 397                         error = -EFAULT;
 398
 399                 goto out;
 400         }
 401         header = (struct swsusp_info *)data_of(snapshot);
 402         if (!enough_swap(header->pages)) {
 403                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 404                 error = -ENOSPC;
 405                 goto out;
 406         }
 407         error = get_swap_writer(&handle);
 408         if (!error) {
 409                 sector_t start = handle.cur_swap;
 410
 411                 error = swap_write_page(&handle, header, NULL);
 412                 if (!error)
 413                         error = save_image(&handle, &snapshot,
 414                                         header->pages - 1);
 415
 416                 if (!error) {
 417                         flush_swap_writer(&handle);
 418                         printk("S");
 419                         error = mark_swapfiles(start, flags);
 420                         printk("|\n");
 421                 }
 422         }
 423         if (error)
 424                 free_all_swap_pages(root_swap);
 425
 426         release_swap_writer(&handle);
 427  out:
 428         swsusp_close();
 429         return error;
 430 }
 431
 432 /**
 433  *      The following functions allow us to read data using a swap map
 434  *      in a file-alike way
 435  */
 436
 437 static void release_swap_reader(struct swap_map_handle *handle)
 438 {
 439         if (handle->cur)
 440                 free_page((unsigned long)handle->cur);
 441         handle->cur = NULL;
 442 }
 443
 444 static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
 445 {
 446         int error;
 447
 448         if (!start)
 449                 return -EINVAL;
 450
 451         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
 452         if (!handle->cur)
 453                 return -ENOMEM;
 454
 455         error = bio_read_page(start, handle->cur, NULL);
 456         if (error) {
 457                 release_swap_reader(handle);
 458                 return error;
 459         }
 460         handle->k = 0;
 461         return 0;
 462 }
 463
 464 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 465                                 struct bio **bio_chain)
 466 {
 467         sector_t offset;
 468         int error;
 469
 470         if (!handle->cur)
 471                 return -EINVAL;
 472         offset = handle->cur->entries[handle->k];
 473         if (!offset)
 474                 return -EFAULT;
 475         error = bio_read_page(offset, buf, bio_chain);
 476         if (error)
 477                 return error;
 478         if (++handle->k >= MAP_PAGE_ENTRIES) {
 479                 error = wait_on_bio_chain(bio_chain);
 480                 handle->k = 0;
 481                 offset = handle->cur->next_swap;
 482                 if (!offset)
 483                         release_swap_reader(handle);
 484                 else if (!error)
 485                         error = bio_read_page(offset, handle->cur, NULL);
 486         }
 487         return error;
 488 }
 489
 490 /**
 491  *      load_image - load the image using the swap map handle
 492  *      @handle and the snapshot handle @snapshot
 493  *      (assume there are @nr_pages pages to load)
 494  */
 495
 496 static int load_image(struct swap_map_handle *handle,
 497                       struct snapshot_handle *snapshot,
 498                       unsigned int nr_to_read)
 499 {
 500         unsigned int m;
 501         int error = 0;
 502         struct timeval start;
 503         struct timeval stop;
 504         struct bio *bio;
 505         int err2;
 506         unsigned nr_pages;
 507
 508         printk("Loading image data pages (%u pages) ...     ", 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("swsusp: block 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);
 576
 577         if (!error)
 578                 pr_debug("swsusp: Reading resume file was successful\n");
 579         else
 580                 pr_debug("swsusp: 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);
 611                 else
 612                         pr_debug("swsusp: Signature found, resuming\n");
 613         } else {
 614                 error = PTR_ERR(resume_bdev);
 615         }
 616
 617         if (error)
 618                 pr_debug("swsusp: Error %d check for resume file\n", error);
 619
 620         return error;
 621 }
 622
 623 /**
 624  *      swsusp_close - close swap device.
 625  */
 626
 627 void swsusp_close(void)
 628 {
 629         if (IS_ERR(resume_bdev)) {
 630                 pr_debug("swsusp: block device not initialised\n");
 631                 return;
 632         }
 633
 634         blkdev_put(resume_bdev);
 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);