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/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/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 static struct swsusp_header {
  36         char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
  37         swp_entry_t image;
  38         char    orig_sig[10];
  39         char    sig[10];
  40 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
  41
  42 /*
  43  * Saving part...
  44  */
  45
  46 static unsigned short root_swap = 0xffff;
  47
  48 static int mark_swapfiles(swp_entry_t start)
  49 {
  50         int error;
  51
  52         rw_swap_page_sync(READ, swp_entry(root_swap, 0),
  53                           virt_to_page((unsigned long)&swsusp_header), NULL);
  54         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
  55             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
  56                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
  57                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
  58                 swsusp_header.image = start;
  59                 error = rw_swap_page_sync(WRITE, swp_entry(root_swap, 0),
  60                                 virt_to_page((unsigned long)&swsusp_header),
  61                                 NULL);
  62         } else {
  63                 pr_debug("swsusp: Partition is not swap space.\n");
  64                 error = -ENODEV;
  65         }
  66         return error;
  67 }
  68
  69 /**
  70  *      swsusp_swap_check - check if the resume device is a swap device
  71  *      and get its index (if so)
  72  */
  73
  74 static int swsusp_swap_check(void) /* This is called before saving image */
  75 {
  76         int res = swap_type_of(swsusp_resume_device);
  77
  78         if (res >= 0) {
  79                 root_swap = res;
  80                 return 0;
  81         }
  82         return res;
  83 }
  84
  85 /**
  86  *      write_page - Write one page to given swap location.
  87  *      @buf:           Address we're writing.
  88  *      @offset:        Offset of the swap page we're writing to.
  89  *      @bio_chain:     Link the next write BIO here
  90  */
  91
  92 static int write_page(void *buf, unsigned long offset, struct bio **bio_chain)
  93 {
  94         swp_entry_t entry;
  95         int error = -ENOSPC;
  96
  97         if (offset) {
  98                 struct page *page = virt_to_page(buf);
  99
 100                 if (bio_chain) {
 101                         /*
 102                          * Whether or not we successfully allocated a copy page,
 103                          * we take a ref on the page here.  It gets undone in
 104                          * wait_on_bio_chain().
 105                          */
 106                         struct page *page_copy;
 107                         page_copy = alloc_page(GFP_ATOMIC);
 108                         if (page_copy == NULL) {
 109                                 WARN_ON_ONCE(1);
 110                                 bio_chain = NULL;       /* Go synchronous */
 111                                 get_page(page);
 112                         } else {
 113                                 memcpy(page_address(page_copy),
 114                                         page_address(page), PAGE_SIZE);
 115                                 page = page_copy;
 116                         }
 117                 }
 118                 entry = swp_entry(root_swap, offset);
 119                 error = rw_swap_page_sync(WRITE, entry, page, bio_chain);
 120         }
 121         return error;
 122 }
 123
 124 /*
 125  *      The swap map is a data structure used for keeping track of each page
 126  *      written to a swap partition.  It consists of many swap_map_page
 127  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 128  *      These structures are stored on the swap and linked together with the
 129  *      help of the .next_swap member.
 130  *
 131  *      The swap map is created during suspend.  The swap map pages are
 132  *      allocated and populated one at a time, so we only need one memory
 133  *      page to set up the entire structure.
 134  *
 135  *      During resume we also only need to use one swap_map_page structure
 136  *      at a time.
 137  */
 138
 139 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(long) - 1)
 140
 141 struct swap_map_page {
 142         unsigned long           entries[MAP_PAGE_ENTRIES];
 143         unsigned long           next_swap;
 144 };
 145
 146 /**
 147  *      The swap_map_handle structure is used for handling swap in
 148  *      a file-alike way
 149  */
 150
 151 struct swap_map_handle {
 152         struct swap_map_page *cur;
 153         unsigned long cur_swap;
 154         struct bitmap_page *bitmap;
 155         unsigned int k;
 156 };
 157
 158 static void release_swap_writer(struct swap_map_handle *handle)
 159 {
 160         if (handle->cur)
 161                 free_page((unsigned long)handle->cur);
 162         handle->cur = NULL;
 163         if (handle->bitmap)
 164                 free_bitmap(handle->bitmap);
 165         handle->bitmap = NULL;
 166 }
 167
 168 static void show_speed(struct timeval *start, struct timeval *stop,
 169                         unsigned nr_pages, char *msg)
 170 {
 171         s64 elapsed_centisecs64;
 172         int centisecs;
 173         int k;
 174         int kps;
 175
 176         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 177         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 178         centisecs = elapsed_centisecs64;
 179         if (centisecs == 0)
 180                 centisecs = 1;  /* avoid div-by-zero */
 181         k = nr_pages * (PAGE_SIZE / 1024);
 182         kps = (k * 100) / centisecs;
 183         printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
 184                         centisecs / 100, centisecs % 100,
 185                         kps / 1000, (kps % 1000) / 10);
 186 }
 187
 188 static int get_swap_writer(struct swap_map_handle *handle)
 189 {
 190         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 191         if (!handle->cur)
 192                 return -ENOMEM;
 193         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 194         if (!handle->bitmap) {
 195                 release_swap_writer(handle);
 196                 return -ENOMEM;
 197         }
 198         handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap);
 199         if (!handle->cur_swap) {
 200                 release_swap_writer(handle);
 201                 return -ENOSPC;
 202         }
 203         handle->k = 0;
 204         return 0;
 205 }
 206
 207 static int wait_on_bio_chain(struct bio **bio_chain)
 208 {
 209         struct bio *bio;
 210         struct bio *next_bio;
 211         int ret = 0;
 212
 213         if (bio_chain == NULL)
 214                 return 0;
 215
 216         bio = *bio_chain;
 217         while (bio) {
 218                 struct page *page;
 219
 220                 next_bio = bio->bi_private;
 221                 page = bio->bi_io_vec[0].bv_page;
 222                 wait_on_page_locked(page);
 223                 if (!PageUptodate(page) || PageError(page))
 224                         ret = -EIO;
 225                 put_page(page);
 226                 bio_put(bio);
 227                 bio = next_bio;
 228         }
 229         *bio_chain = NULL;
 230         return ret;
 231 }
 232
 233 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 234                                 struct bio **bio_chain)
 235 {
 236         int error = 0;
 237         unsigned long offset;
 238
 239         if (!handle->cur)
 240                 return -EINVAL;
 241         offset = alloc_swap_page(root_swap, handle->bitmap);
 242         error = write_page(buf, offset, bio_chain);
 243         if (error)
 244                 return error;
 245         handle->cur->entries[handle->k++] = offset;
 246         if (handle->k >= MAP_PAGE_ENTRIES) {
 247                 error = wait_on_bio_chain(bio_chain);
 248                 if (error)
 249                         goto out;
 250                 offset = alloc_swap_page(root_swap, handle->bitmap);
 251                 if (!offset)
 252                         return -ENOSPC;
 253                 handle->cur->next_swap = offset;
 254                 error = write_page(handle->cur, handle->cur_swap, NULL);
 255                 if (error)
 256                         goto out;
 257                 memset(handle->cur, 0, PAGE_SIZE);
 258                 handle->cur_swap = offset;
 259                 handle->k = 0;
 260         }
 261 out:
 262         return error;
 263 }
 264
 265 static int flush_swap_writer(struct swap_map_handle *handle)
 266 {
 267         if (handle->cur && handle->cur_swap)
 268                 return write_page(handle->cur, handle->cur_swap, NULL);
 269         else
 270                 return -EINVAL;
 271 }
 272
 273 /**
 274  *      save_image - save the suspend image data
 275  */
 276
 277 static int save_image(struct swap_map_handle *handle,
 278                       struct snapshot_handle *snapshot,
 279                       unsigned int nr_to_write)
 280 {
 281         unsigned int m;
 282         int ret;
 283         int error = 0;
 284         int nr_pages;
 285         int err2;
 286         struct bio *bio;
 287         struct timeval start;
 288         struct timeval stop;
 289
 290         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 291         m = nr_to_write / 100;
 292         if (!m)
 293                 m = 1;
 294         nr_pages = 0;
 295         bio = NULL;
 296         do_gettimeofday(&start);
 297         do {
 298                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 299                 if (ret > 0) {
 300                         error = swap_write_page(handle, data_of(*snapshot),
 301                                                 &bio);
 302                         if (error)
 303                                 break;
 304                         if (!(nr_pages % m))
 305                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 306                         nr_pages++;
 307                 }
 308         } while (ret > 0);
 309         err2 = wait_on_bio_chain(&bio);
 310         do_gettimeofday(&stop);
 311         if (!error)
 312                 error = err2;
 313         if (!error)
 314                 printk("\b\b\b\bdone\n");
 315         show_speed(&start, &stop, nr_to_write, "Wrote");
 316         return error;
 317 }
 318
 319 /**
 320  *      enough_swap - Make sure we have enough swap to save the image.
 321  *
 322  *      Returns TRUE or FALSE after checking the total amount of swap
 323  *      space avaiable from the resume partition.
 324  */
 325
 326 static int enough_swap(unsigned int nr_pages)
 327 {
 328         unsigned int free_swap = count_swap_pages(root_swap, 1);
 329
 330         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 331         return free_swap > (nr_pages + PAGES_FOR_IO +
 332                 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 333 }
 334
 335 /**
 336  *      swsusp_write - Write entire image and metadata.
 337  *
 338  *      It is important _NOT_ to umount filesystems at this point. We want
 339  *      them synced (in case something goes wrong) but we DO not want to mark
 340  *      filesystem clean: it is not. (And it does not matter, if we resume
 341  *      correctly, we'll mark system clean, anyway.)
 342  */
 343
 344 int swsusp_write(void)
 345 {
 346         struct swap_map_handle handle;
 347         struct snapshot_handle snapshot;
 348         struct swsusp_info *header;
 349         int error;
 350
 351         if ((error = swsusp_swap_check())) {
 352                 printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n");
 353                 return error;
 354         }
 355         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 356         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 357         if (error < PAGE_SIZE)
 358                 return error < 0 ? error : -EFAULT;
 359         header = (struct swsusp_info *)data_of(snapshot);
 360         if (!enough_swap(header->pages)) {
 361                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 362                 return -ENOSPC;
 363         }
 364         error = get_swap_writer(&handle);
 365         if (!error) {
 366                 unsigned long start = handle.cur_swap;
 367                 error = swap_write_page(&handle, header, NULL);
 368                 if (!error)
 369                         error = save_image(&handle, &snapshot,
 370                                         header->pages - 1);
 371                 if (!error) {
 372                         flush_swap_writer(&handle);
 373                         printk("S");
 374                         error = mark_swapfiles(swp_entry(root_swap, start));
 375                         printk("|\n");
 376                 }
 377         }
 378         if (error)
 379                 free_all_swap_pages(root_swap, handle.bitmap);
 380         release_swap_writer(&handle);
 381         return error;
 382 }
 383
 384 /*
 385  *      Using bio to read from swap.
 386  *      This code requires a bit more work than just using buffer heads
 387  *      but, it is the recommended way for 2.5/2.6.
 388  *      The following are to signal the beginning and end of I/O. Bios
 389  *      finish asynchronously, while we want them to happen synchronously.
 390  *      A simple atomic_t, and a wait loop take care of this problem.
 391  */
 392
 393 static atomic_t io_done = ATOMIC_INIT(0);
 394
 395 static int end_io(struct bio *bio, unsigned int num, int err)
 396 {
 397         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 398                 printk(KERN_ERR "I/O error reading swsusp image.\n");
 399                 return -EIO;
 400         }
 401         atomic_set(&io_done, 0);
 402         return 0;
 403 }
 404
 405 static struct block_device *resume_bdev;
 406
 407 /**
 408  *      submit - submit BIO request.
 409  *      @rw:    READ or WRITE.
 410  *      @off    physical offset of page.
 411  *      @page:  page we're reading or writing.
 412  *
 413  *      Straight from the textbook - allocate and initialize the bio.
 414  *      If we're writing, make sure the page is marked as dirty.
 415  *      Then submit it and wait.
 416  */
 417
 418 static int submit(int rw, pgoff_t page_off, void *page)
 419 {
 420         int error = 0;
 421         struct bio *bio;
 422
 423         bio = bio_alloc(GFP_ATOMIC, 1);
 424         if (!bio)
 425                 return -ENOMEM;
 426         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
 427         bio->bi_bdev = resume_bdev;
 428         bio->bi_end_io = end_io;
 429
 430         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
 431                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
 432                 error = -EFAULT;
 433                 goto Done;
 434         }
 435
 436         atomic_set(&io_done, 1);
 437         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
 438         while (atomic_read(&io_done))
 439                 yield();
 440         if (rw == READ)
 441                 bio_set_pages_dirty(bio);
 442  Done:
 443         bio_put(bio);
 444         return error;
 445 }
 446
 447 static int bio_read_page(pgoff_t page_off, void *page)
 448 {
 449         return submit(READ, page_off, page);
 450 }
 451
 452 static int bio_write_page(pgoff_t page_off, void *page)
 453 {
 454         return submit(WRITE, page_off, page);
 455 }
 456
 457 /**
 458  *      The following functions allow us to read data using a swap map
 459  *      in a file-alike way
 460  */
 461
 462 static void release_swap_reader(struct swap_map_handle *handle)
 463 {
 464         if (handle->cur)
 465                 free_page((unsigned long)handle->cur);
 466         handle->cur = NULL;
 467 }
 468
 469 static int get_swap_reader(struct swap_map_handle *handle,
 470                                       swp_entry_t start)
 471 {
 472         int error;
 473
 474         if (!swp_offset(start))
 475                 return -EINVAL;
 476         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
 477         if (!handle->cur)
 478                 return -ENOMEM;
 479         error = bio_read_page(swp_offset(start), handle->cur);
 480         if (error) {
 481                 release_swap_reader(handle);
 482                 return error;
 483         }
 484         handle->k = 0;
 485         return 0;
 486 }
 487
 488 static int swap_read_page(struct swap_map_handle *handle, void *buf)
 489 {
 490         unsigned long offset;
 491         int error;
 492
 493         if (!handle->cur)
 494                 return -EINVAL;
 495         offset = handle->cur->entries[handle->k];
 496         if (!offset)
 497                 return -EFAULT;
 498         error = bio_read_page(offset, buf);
 499         if (error)
 500                 return error;
 501         if (++handle->k >= MAP_PAGE_ENTRIES) {
 502                 handle->k = 0;
 503                 offset = handle->cur->next_swap;
 504                 if (!offset)
 505                         release_swap_reader(handle);
 506                 else
 507                         error = bio_read_page(offset, handle->cur);
 508         }
 509         return error;
 510 }
 511
 512 /**
 513  *      load_image - load the image using the swap map handle
 514  *      @handle and the snapshot handle @snapshot
 515  *      (assume there are @nr_pages pages to load)
 516  */
 517
 518 static int load_image(struct swap_map_handle *handle,
 519                       struct snapshot_handle *snapshot,
 520                       unsigned int nr_pages)
 521 {
 522         unsigned int m;
 523         int ret;
 524         int error = 0;
 525         struct timeval start;
 526         struct timeval stop;
 527
 528         printk("Loading image data pages (%u pages) ...     ", nr_pages);
 529         m = nr_pages / 100;
 530         if (!m)
 531                 m = 1;
 532         nr_pages = 0;
 533         do_gettimeofday(&start);
 534         do {
 535                 ret = snapshot_write_next(snapshot, PAGE_SIZE);
 536                 if (ret > 0) {
 537                         error = swap_read_page(handle, data_of(*snapshot));
 538                         if (error)
 539                                 break;
 540                         if (!(nr_pages % m))
 541                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 542                         nr_pages++;
 543                 }
 544         } while (ret > 0);
 545         do_gettimeofday(&stop);
 546         if (!error) {
 547                 printk("\b\b\b\bdone\n");
 548                 if (!snapshot_image_loaded(snapshot))
 549                         error = -ENODATA;
 550         }
 551         show_speed(&start, &stop, nr_pages, "Read");
 552         return error;
 553 }
 554
 555 int swsusp_read(void)
 556 {
 557         int error;
 558         struct swap_map_handle handle;
 559         struct snapshot_handle snapshot;
 560         struct swsusp_info *header;
 561
 562         if (IS_ERR(resume_bdev)) {
 563                 pr_debug("swsusp: block device not initialised\n");
 564                 return PTR_ERR(resume_bdev);
 565         }
 566
 567         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 568         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 569         if (error < PAGE_SIZE)
 570                 return error < 0 ? error : -EFAULT;
 571         header = (struct swsusp_info *)data_of(snapshot);
 572         error = get_swap_reader(&handle, swsusp_header.image);
 573         if (!error)
 574                 error = swap_read_page(&handle, header);
 575         if (!error)
 576                 error = load_image(&handle, &snapshot, header->pages - 1);
 577         release_swap_reader(&handle);
 578
 579         blkdev_put(resume_bdev);
 580
 581         if (!error)
 582                 pr_debug("swsusp: Reading resume file was successful\n");
 583         else
 584                 pr_debug("swsusp: Error %d resuming\n", error);
 585         return error;
 586 }
 587
 588 /**
 589  *      swsusp_check - Check for swsusp signature in the resume device
 590  */
 591
 592 int swsusp_check(void)
 593 {
 594         int error;
 595
 596         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 597         if (!IS_ERR(resume_bdev)) {
 598                 set_blocksize(resume_bdev, PAGE_SIZE);
 599                 memset(&swsusp_header, 0, sizeof(swsusp_header));
 600                 if ((error = bio_read_page(0, &swsusp_header)))
 601                         return error;
 602                 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 603                         memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 604                         /* Reset swap signature now */
 605                         error = bio_write_page(0, &swsusp_header);
 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 }