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/smp_lock.h>
  16 #include <linux/file.h>
  17 #include <linux/utsname.h>
  18 #include <linux/version.h>
  19 #include <linux/delay.h>
  20 #include <linux/bitops.h>
  21 #include <linux/genhd.h>
  22 #include <linux/device.h>
  23 #include <linux/buffer_head.h>
  24 #include <linux/bio.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/swap.h>
  27 #include <linux/swapops.h>
  28 #include <linux/pm.h>
  29
  30 #include "power.h"
  31
  32 extern char resume_file[];
  33
  34 #define SWSUSP_SIG      "S1SUSPEND"
  35
  36 struct swsusp_header {
  37         char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
  38         sector_t image;
  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)
 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                 error = bio_write_page(swsusp_resume_block,
 153                                         swsusp_header, NULL);
 154         } else {
 155                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 156                 error = -ENODEV;
 157         }
 158         return error;
 159 }
 160
 161 /**
 162  *      swsusp_swap_check - check if the resume device is a swap device
 163  *      and get its index (if so)
 164  */
 165
 166 static int swsusp_swap_check(void) /* This is called before saving image */
 167 {
 168         int res;
 169
 170         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
 171                         &resume_bdev);
 172         if (res < 0)
 173                 return res;
 174
 175         root_swap = res;
 176         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
 177         if (res)
 178                 return res;
 179
 180         res = set_blocksize(resume_bdev, PAGE_SIZE);
 181         if (res < 0)
 182                 blkdev_put(resume_bdev);
 183
 184         return res;
 185 }
 186
 187 /**
 188  *      write_page - Write one page to given swap location.
 189  *      @buf:           Address we're writing.
 190  *      @offset:        Offset of the swap page we're writing to.
 191  *      @bio_chain:     Link the next write BIO here
 192  */
 193
 194 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 195 {
 196         void *src;
 197
 198         if (!offset)
 199                 return -ENOSPC;
 200
 201         if (bio_chain) {
 202                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
 203                 if (src) {
 204                         memcpy(src, buf, PAGE_SIZE);
 205                 } else {
 206                         WARN_ON_ONCE(1);
 207                         bio_chain = NULL;       /* Go synchronous */
 208                         src = buf;
 209                 }
 210         } else {
 211                 src = buf;
 212         }
 213         return bio_write_page(offset, src, bio_chain);
 214 }
 215
 216 /*
 217  *      The swap map is a data structure used for keeping track of each page
 218  *      written to a swap partition.  It consists of many swap_map_page
 219  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 220  *      These structures are stored on the swap and linked together with the
 221  *      help of the .next_swap member.
 222  *
 223  *      The swap map is created during suspend.  The swap map pages are
 224  *      allocated and populated one at a time, so we only need one memory
 225  *      page to set up the entire structure.
 226  *
 227  *      During resume we also only need to use one swap_map_page structure
 228  *      at a time.
 229  */
 230
 231 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 232
 233 struct swap_map_page {
 234         sector_t entries[MAP_PAGE_ENTRIES];
 235         sector_t next_swap;
 236 };
 237
 238 /**
 239  *      The swap_map_handle structure is used for handling swap in
 240  *      a file-alike way
 241  */
 242
 243 struct swap_map_handle {
 244         struct swap_map_page *cur;
 245         sector_t cur_swap;
 246         unsigned int k;
 247 };
 248
 249 static void release_swap_writer(struct swap_map_handle *handle)
 250 {
 251         if (handle->cur)
 252                 free_page((unsigned long)handle->cur);
 253         handle->cur = NULL;
 254 }
 255
 256 static int get_swap_writer(struct swap_map_handle *handle)
 257 {
 258         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 259         if (!handle->cur)
 260                 return -ENOMEM;
 261         handle->cur_swap = alloc_swapdev_block(root_swap);
 262         if (!handle->cur_swap) {
 263                 release_swap_writer(handle);
 264                 return -ENOSPC;
 265         }
 266         handle->k = 0;
 267         return 0;
 268 }
 269
 270 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 271                                 struct bio **bio_chain)
 272 {
 273         int error = 0;
 274         sector_t offset;
 275
 276         if (!handle->cur)
 277                 return -EINVAL;
 278         offset = alloc_swapdev_block(root_swap);
 279         error = write_page(buf, offset, bio_chain);
 280         if (error)
 281                 return error;
 282         handle->cur->entries[handle->k++] = offset;
 283         if (handle->k >= MAP_PAGE_ENTRIES) {
 284                 error = wait_on_bio_chain(bio_chain);
 285                 if (error)
 286                         goto out;
 287                 offset = alloc_swapdev_block(root_swap);
 288                 if (!offset)
 289                         return -ENOSPC;
 290                 handle->cur->next_swap = offset;
 291                 error = write_page(handle->cur, handle->cur_swap, NULL);
 292                 if (error)
 293                         goto out;
 294                 memset(handle->cur, 0, PAGE_SIZE);
 295                 handle->cur_swap = offset;
 296                 handle->k = 0;
 297         }
 298  out:
 299         return error;
 300 }
 301
 302 static int flush_swap_writer(struct swap_map_handle *handle)
 303 {
 304         if (handle->cur && handle->cur_swap)
 305                 return write_page(handle->cur, handle->cur_swap, NULL);
 306         else
 307                 return -EINVAL;
 308 }
 309
 310 /**
 311  *      save_image - save the suspend image data
 312  */
 313
 314 static int save_image(struct swap_map_handle *handle,
 315                       struct snapshot_handle *snapshot,
 316                       unsigned int nr_to_write)
 317 {
 318         unsigned int m;
 319         int ret;
 320         int error = 0;
 321         int nr_pages;
 322         int err2;
 323         struct bio *bio;
 324         struct timeval start;
 325         struct timeval stop;
 326
 327         printk("Saving image data pages (%u pages) ...     ", 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("swsusp: 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  *
 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(void)
 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);
 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 int swsusp_read(void)
 545 {
 546         int error;
 547         struct swap_map_handle handle;
 548         struct snapshot_handle snapshot;
 549         struct swsusp_info *header;
 550
 551         if (IS_ERR(resume_bdev)) {
 552                 pr_debug("swsusp: block device not initialised\n");
 553                 return PTR_ERR(resume_bdev);
 554         }
 555
 556         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 557         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 558         if (error < PAGE_SIZE)
 559                 return error < 0 ? error : -EFAULT;
 560         header = (struct swsusp_info *)data_of(snapshot);
 561         error = get_swap_reader(&handle, swsusp_header->image);
 562         if (!error)
 563                 error = swap_read_page(&handle, header, NULL);
 564         if (!error)
 565                 error = load_image(&handle, &snapshot, header->pages - 1);
 566         release_swap_reader(&handle);
 567
 568         blkdev_put(resume_bdev);
 569
 570         if (!error)
 571                 pr_debug("swsusp: Reading resume file was successful\n");
 572         else
 573                 pr_debug("swsusp: Error %d resuming\n", error);
 574         return error;
 575 }
 576
 577 /**
 578  *      swsusp_check - Check for swsusp signature in the resume device
 579  */
 580
 581 int swsusp_check(void)
 582 {
 583         int error;
 584
 585         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 586         if (!IS_ERR(resume_bdev)) {
 587                 set_blocksize(resume_bdev, PAGE_SIZE);
 588                 memset(swsusp_header, 0, sizeof(PAGE_SIZE));
 589                 error = bio_read_page(swsusp_resume_block,
 590                                         swsusp_header, NULL);
 591                 if (error)
 592                         return error;
 593
 594                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
 595                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 596                         /* Reset swap signature now */
 597                         error = bio_write_page(swsusp_resume_block,
 598                                                 swsusp_header, NULL);
 599                 } else {
 600                         return -EINVAL;
 601                 }
 602                 if (error)
 603                         blkdev_put(resume_bdev);
 604                 else
 605                         pr_debug("swsusp: Signature found, resuming\n");
 606         } else {
 607                 error = PTR_ERR(resume_bdev);
 608         }
 609
 610         if (error)
 611                 pr_debug("swsusp: Error %d check for resume file\n", error);
 612
 613         return error;
 614 }
 615
 616 /**
 617  *      swsusp_close - close swap device.
 618  */
 619
 620 void swsusp_close(void)
 621 {
 622         if (IS_ERR(resume_bdev)) {
 623                 pr_debug("swsusp: block device not initialised\n");
 624                 return;
 625         }
 626
 627         blkdev_put(resume_bdev);
 628 }
 629
 630 static int swsusp_header_init(void)
 631 {
 632         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
 633         if (!swsusp_header)
 634                 panic("Could not allocate memory for swsusp_header\n");
 635         return 0;
 636 }
 637
 638 core_initcall(swsusp_header_init);