kernel/power/swsusp.c

   1 /*
   2  * linux/kernel/power/swsusp.c
   3  *
   4  * This file provides code to write suspend image to swap and read it back.
   5  *
   6  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  * I'd like to thank the following people for their work:
  12  *
  13  * Pavel Machek <pavel@ucw.cz>:
  14  * Modifications, defectiveness pointing, being with me at the very beginning,
  15  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
  16  *
  17  * Steve Doddi <dirk@loth.demon.co.uk>:
  18  * Support the possibility of hardware state restoring.
  19  *
  20  * Raph <grey.havens@earthling.net>:
  21  * Support for preserving states of network devices and virtual console
  22  * (including X and svgatextmode)
  23  *
  24  * Kurt Garloff <garloff@suse.de>:
  25  * Straightened the critical function in order to prevent compilers from
  26  * playing tricks with local variables.
  27  *
  28  * Andreas Mohr <a.mohr@mailto.de>
  29  *
  30  * Alex Badea <vampire@go.ro>:
  31  * Fixed runaway init
  32  *
  33  * More state savers are welcome. Especially for the scsi layer...
  34  *
  35  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
  36  */
  37
  38 #include <linux/module.h>
  39 #include <linux/mm.h>
  40 #include <linux/suspend.h>
  41 #include <linux/smp_lock.h>
  42 #include <linux/file.h>
  43 #include <linux/utsname.h>
  44 #include <linux/version.h>
  45 #include <linux/delay.h>
  46 #include <linux/bitops.h>
  47 #include <linux/spinlock.h>
  48 #include <linux/genhd.h>
  49 #include <linux/kernel.h>
  50 #include <linux/major.h>
  51 #include <linux/swap.h>
  52 #include <linux/pm.h>
  53 #include <linux/device.h>
  54 #include <linux/buffer_head.h>
  55 #include <linux/swapops.h>
  56 #include <linux/bootmem.h>
  57 #include <linux/syscalls.h>
  58 #include <linux/highmem.h>
  59 #include <linux/bio.h>
  60
  61 #include <asm/uaccess.h>
  62 #include <asm/mmu_context.h>
  63 #include <asm/pgtable.h>
  64 #include <asm/tlbflush.h>
  65 #include <asm/io.h>
  66
  67 #include "power.h"
  68
  69 #ifdef CONFIG_HIGHMEM
  70 int save_highmem(void);
  71 int restore_highmem(void);
  72 #else
  73 static int save_highmem(void) { return 0; }
  74 static int restore_highmem(void) { return 0; }
  75 #endif
  76
  77 extern char resume_file[];
  78
  79 /* Local variables that should not be affected by save */
  80 unsigned int nr_copy_pages __nosavedata = 0;
  81
  82 /* Suspend pagedir is allocated before final copy, therefore it
  83    must be freed after resume
  84
  85    Warning: this is even more evil than it seems. Pagedirs this file
  86    talks about are completely different from page directories used by
  87    MMU hardware.
  88  */
  89 suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
  90
  91 #define SWSUSP_SIG      "S1SUSPEND"
  92
  93 static struct swsusp_header {
  94         char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
  95         swp_entry_t swsusp_info;
  96         char    orig_sig[10];
  97         char    sig[10];
  98 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
  99
 100 static struct swsusp_info swsusp_info;
 101
 102 /*
 103  * Saving part...
 104  */
 105
 106 /* We memorize in swapfile_used what swap devices are used for suspension */
 107 #define SWAPFILE_UNUSED    0
 108 #define SWAPFILE_SUSPEND   1    /* This is the suspending device */
 109 #define SWAPFILE_IGNORED   2    /* Those are other swap devices ignored for suspension */
 110
 111 static unsigned short swapfile_used[MAX_SWAPFILES];
 112 static unsigned short root_swap;
 113
 114 static int mark_swapfiles(swp_entry_t prev)
 115 {
 116         int error;
 117
 118         rw_swap_page_sync(READ,
 119                           swp_entry(root_swap, 0),
 120                           virt_to_page((unsigned long)&swsusp_header));
 121         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
 122             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
 123                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 124                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 125                 swsusp_header.swsusp_info = prev;
 126                 error = rw_swap_page_sync(WRITE,
 127                                           swp_entry(root_swap, 0),
 128                                           virt_to_page((unsigned long)
 129                                                        &swsusp_header));
 130         } else {
 131                 pr_debug("swsusp: Partition is not swap space.\n");
 132                 error = -ENODEV;
 133         }
 134         return error;
 135 }
 136
 137 /*
 138  * Check whether the swap device is the specified resume
 139  * device, irrespective of whether they are specified by
 140  * identical names.
 141  *
 142  * (Thus, device inode aliasing is allowed.  You can say /dev/hda4
 143  * instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
 144  * and they'll be considered the same device.  This is *necessary* for
 145  * devfs, since the resume code can only recognize the form /dev/hda4,
 146  * but the suspend code would see the long name.)
 147  */
 148 static int is_resume_device(const struct swap_info_struct *swap_info)
 149 {
 150         struct file *file = swap_info->swap_file;
 151         struct inode *inode = file->f_dentry->d_inode;
 152
 153         return S_ISBLK(inode->i_mode) &&
 154                 swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
 155 }
 156
 157 static int swsusp_swap_check(void) /* This is called before saving image */
 158 {
 159         int i, len;
 160
 161         len=strlen(resume_file);
 162         root_swap = 0xFFFF;
 163
 164         spin_lock(&swap_lock);
 165         for (i=0; i<MAX_SWAPFILES; i++) {
 166                 if (!(swap_info[i].flags & SWP_WRITEOK)) {
 167                         swapfile_used[i]=SWAPFILE_UNUSED;
 168                 } else {
 169                         if (!len) {
 170                                 printk(KERN_WARNING "resume= option should be used to set suspend device" );
 171                                 if (root_swap == 0xFFFF) {
 172                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 173                                         root_swap = i;
 174                                 } else
 175                                         swapfile_used[i] = SWAPFILE_IGNORED;
 176                         } else {
 177                                 /* we ignore all swap devices that are not the resume_file */
 178                                 if (is_resume_device(&swap_info[i])) {
 179                                         swapfile_used[i] = SWAPFILE_SUSPEND;
 180                                         root_swap = i;
 181                                 } else {
 182                                         swapfile_used[i] = SWAPFILE_IGNORED;
 183                                 }
 184                         }
 185                 }
 186         }
 187         spin_unlock(&swap_lock);
 188         return (root_swap != 0xffff) ? 0 : -ENODEV;
 189 }
 190
 191 /**
 192  * This is called after saving image so modification
 193  * will be lost after resume... and that's what we want.
 194  * we make the device unusable. A new call to
 195  * lock_swapdevices can unlock the devices.
 196  */
 197 static void lock_swapdevices(void)
 198 {
 199         int i;
 200
 201         spin_lock(&swap_lock);
 202         for (i = 0; i< MAX_SWAPFILES; i++)
 203                 if (swapfile_used[i] == SWAPFILE_IGNORED) {
 204                         swap_info[i].flags ^= SWP_WRITEOK;
 205                 }
 206         spin_unlock(&swap_lock);
 207 }
 208
 209 /**
 210  *      write_page - Write one page to a fresh swap location.
 211  *      @addr:  Address we're writing.
 212  *      @loc:   Place to store the entry we used.
 213  *
 214  *      Allocate a new swap entry and 'sync' it. Note we discard -EIO
 215  *      errors. That is an artifact left over from swsusp. It did not
 216  *      check the return of rw_swap_page_sync() at all, since most pages
 217  *      written back to swap would return -EIO.
 218  *      This is a partial improvement, since we will at least return other
 219  *      errors, though we need to eventually fix the damn code.
 220  */
 221 static int write_page(unsigned long addr, swp_entry_t *loc)
 222 {
 223         swp_entry_t entry;
 224         int error = 0;
 225
 226         entry = get_swap_page();
 227         if (swp_offset(entry) &&
 228             swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
 229                 error = rw_swap_page_sync(WRITE, entry,
 230                                           virt_to_page(addr));
 231                 if (error == -EIO)
 232                         error = 0;
 233                 if (!error)
 234                         *loc = entry;
 235         } else
 236                 error = -ENOSPC;
 237         return error;
 238 }
 239
 240 /**
 241  *      data_free - Free the swap entries used by the saved image.
 242  *
 243  *      Walk the list of used swap entries and free each one.
 244  *      This is only used for cleanup when suspend fails.
 245  */
 246 static void data_free(void)
 247 {
 248         swp_entry_t entry;
 249         struct pbe *p;
 250
 251         for_each_pbe (p, pagedir_nosave) {
 252                 entry = p->swap_address;
 253                 if (entry.val)
 254                         swap_free(entry);
 255                 else
 256                         break;
 257         }
 258 }
 259
 260 /**
 261  *      data_write - Write saved image to swap.
 262  *
 263  *      Walk the list of pages in the image and sync each one to swap.
 264  */
 265 static int data_write(void)
 266 {
 267         int error = 0, i = 0;
 268         unsigned int mod = nr_copy_pages / 100;
 269         struct pbe *p;
 270
 271         if (!mod)
 272                 mod = 1;
 273
 274         printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
 275         for_each_pbe (p, pagedir_nosave) {
 276                 if (!(i%mod))
 277                         printk( "\b\b\b\b%3d%%", i / mod );
 278                 if ((error = write_page(p->address, &p->swap_address)))
 279                         return error;
 280                 i++;
 281         }
 282         printk("\b\b\b\bdone\n");
 283         return error;
 284 }
 285
 286 static void dump_info(void)
 287 {
 288         pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
 289         pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
 290         pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
 291         pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
 292         pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
 293         pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
 294         pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
 295         pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
 296         pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
 297         pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
 298         pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
 299 }
 300
 301 static void init_header(void)
 302 {
 303         memset(&swsusp_info, 0, sizeof(swsusp_info));
 304         swsusp_info.version_code = LINUX_VERSION_CODE;
 305         swsusp_info.num_physpages = num_physpages;
 306         memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
 307
 308         swsusp_info.suspend_pagedir = pagedir_nosave;
 309         swsusp_info.cpus = num_online_cpus();
 310         swsusp_info.image_pages = nr_copy_pages;
 311 }
 312
 313 static int close_swap(void)
 314 {
 315         swp_entry_t entry;
 316         int error;
 317
 318         dump_info();
 319         error = write_page((unsigned long)&swsusp_info, &entry);
 320         if (!error) {
 321                 printk( "S" );
 322                 error = mark_swapfiles(entry);
 323                 printk( "|\n" );
 324         }
 325         return error;
 326 }
 327
 328 /**
 329  *      free_pagedir_entries - Free pages used by the page directory.
 330  *
 331  *      This is used during suspend for error recovery.
 332  */
 333
 334 static void free_pagedir_entries(void)
 335 {
 336         int i;
 337
 338         for (i = 0; i < swsusp_info.pagedir_pages; i++)
 339                 swap_free(swsusp_info.pagedir[i]);
 340 }
 341
 342
 343 /**
 344  *      write_pagedir - Write the array of pages holding the page directory.
 345  *      @last:  Last swap entry we write (needed for header).
 346  */
 347
 348 static int write_pagedir(void)
 349 {
 350         int error = 0;
 351         unsigned int n = 0;
 352         struct pbe *pbe;
 353
 354         printk( "Writing pagedir...");
 355         for_each_pb_page (pbe, pagedir_nosave) {
 356                 if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
 357                         return error;
 358         }
 359
 360         swsusp_info.pagedir_pages = n;
 361         printk("done (%u pages)\n", n);
 362         return error;
 363 }
 364
 365 /**
 366  *      enough_swap - Make sure we have enough swap to save the image.
 367  *
 368  *      Returns TRUE or FALSE after checking the total amount of swap
 369  *      space avaiable.
 370  *
 371  *      FIXME: si_swapinfo(&i) returns all swap devices information.
 372  *      We should only consider resume_device.
 373  */
 374
 375 static int enough_swap(unsigned int nr_pages)
 376 {
 377         struct sysinfo i;
 378
 379         si_swapinfo(&i);
 380         pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
 381         return i.freeswap > (nr_pages + PAGES_FOR_IO +
 382                 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 383 }
 384
 385 /**
 386  *      write_suspend_image - Write entire image and metadata.
 387  *
 388  */
 389 static int write_suspend_image(void)
 390 {
 391         int error;
 392
 393         if (!enough_swap(nr_copy_pages)) {
 394                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 395                 return -ENOSPC;
 396         }
 397
 398         init_header();
 399         if ((error = data_write()))
 400                 goto FreeData;
 401
 402         if ((error = write_pagedir()))
 403                 goto FreePagedir;
 404
 405         if ((error = close_swap()))
 406                 goto FreePagedir;
 407  Done:
 408         return error;
 409  FreePagedir:
 410         free_pagedir_entries();
 411  FreeData:
 412         data_free();
 413         goto Done;
 414 }
 415
 416 /* It is important _NOT_ to umount filesystems at this point. We want
 417  * them synced (in case something goes wrong) but we DO not want to mark
 418  * filesystem clean: it is not. (And it does not matter, if we resume
 419  * correctly, we'll mark system clean, anyway.)
 420  */
 421 int swsusp_write(void)
 422 {
 423         int error;
 424
 425         if ((error = swsusp_swap_check())) {
 426                 printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
 427                 return error;
 428         }
 429         lock_swapdevices();
 430         error = write_suspend_image();
 431         /* This will unlock ignored swap devices since writing is finished */
 432         lock_swapdevices();
 433         return error;
 434 }
 435
 436
 437
 438 int swsusp_suspend(void)
 439 {
 440         int error;
 441
 442         if ((error = arch_prepare_suspend()))
 443                 return error;
 444         local_irq_disable();
 445         /* At this point, device_suspend() has been called, but *not*
 446          * device_power_down(). We *must* device_power_down() now.
 447          * Otherwise, drivers for some devices (e.g. interrupt controllers)
 448          * become desynchronized with the actual state of the hardware
 449          * at resume time, and evil weirdness ensues.
 450          */
 451         if ((error = device_power_down(PMSG_FREEZE))) {
 452                 printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
 453                 goto Enable_irqs;
 454         }
 455
 456         if ((error = save_highmem())) {
 457                 printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
 458                 goto Restore_highmem;
 459         }
 460
 461         save_processor_state();
 462         if ((error = swsusp_arch_suspend()))
 463                 printk(KERN_ERR "Error %d suspending\n", error);
 464         /* Restore control flow magically appears here */
 465         restore_processor_state();
 466 Restore_highmem:
 467         restore_highmem();
 468         device_power_up();
 469 Enable_irqs:
 470         local_irq_enable();
 471         return error;
 472 }
 473
 474 int swsusp_resume(void)
 475 {
 476         int error;
 477         local_irq_disable();
 478         if (device_power_down(PMSG_FREEZE))
 479                 printk(KERN_ERR "Some devices failed to power down, very bad\n");
 480         /* We'll ignore saved state, but this gets preempt count (etc) right */
 481         save_processor_state();
 482         error = swsusp_arch_resume();
 483         /* Code below is only ever reached in case of failure. Otherwise
 484          * execution continues at place where swsusp_arch_suspend was called
 485          */
 486         BUG_ON(!error);
 487         /* The only reason why swsusp_arch_resume() can fail is memory being
 488          * very tight, so we have to free it as soon as we can to avoid
 489          * subsequent failures
 490          */
 491         swsusp_free();
 492         restore_processor_state();
 493         restore_highmem();
 494         touch_softlockup_watchdog();
 495         device_power_up();
 496         local_irq_enable();
 497         return error;
 498 }
 499
 500 /**
 501  *      mark_unsafe_pages - mark the pages that cannot be used for storing
 502  *      the image during resume, because they conflict with the pages that
 503  *      had been used before suspend
 504  */
 505
 506 static void mark_unsafe_pages(struct pbe *pblist)
 507 {
 508         struct zone *zone;
 509         unsigned long zone_pfn;
 510         struct pbe *p;
 511
 512         if (!pblist) /* a sanity check */
 513                 return;
 514
 515         /* Clear page flags */
 516         for_each_zone (zone) {
 517                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
 518                         if (pfn_valid(zone_pfn + zone->zone_start_pfn))
 519                                 ClearPageNosaveFree(pfn_to_page(zone_pfn +
 520                                         zone->zone_start_pfn));
 521         }
 522
 523         /* Mark orig addresses */
 524         for_each_pbe (p, pblist)
 525                 SetPageNosaveFree(virt_to_page(p->orig_address));
 526
 527 }
 528
 529 static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
 530 {
 531         /* We assume both lists contain the same number of elements */
 532         while (src) {
 533                 dst->orig_address = src->orig_address;
 534                 dst->swap_address = src->swap_address;
 535                 dst = dst->next;
 536                 src = src->next;
 537         }
 538 }
 539
 540 /*
 541  *      Using bio to read from swap.
 542  *      This code requires a bit more work than just using buffer heads
 543  *      but, it is the recommended way for 2.5/2.6.
 544  *      The following are to signal the beginning and end of I/O. Bios
 545  *      finish asynchronously, while we want them to happen synchronously.
 546  *      A simple atomic_t, and a wait loop take care of this problem.
 547  */
 548
 549 static atomic_t io_done = ATOMIC_INIT(0);
 550
 551 static int end_io(struct bio *bio, unsigned int num, int err)
 552 {
 553         if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
 554                 panic("I/O error reading memory image");
 555         atomic_set(&io_done, 0);
 556         return 0;
 557 }
 558
 559 static struct block_device *resume_bdev;
 560
 561 /**
 562  *      submit - submit BIO request.
 563  *      @rw:    READ or WRITE.
 564  *      @off    physical offset of page.
 565  *      @page:  page we're reading or writing.
 566  *
 567  *      Straight from the textbook - allocate and initialize the bio.
 568  *      If we're writing, make sure the page is marked as dirty.
 569  *      Then submit it and wait.
 570  */
 571
 572 static int submit(int rw, pgoff_t page_off, void *page)
 573 {
 574         int error = 0;
 575         struct bio *bio;
 576
 577         bio = bio_alloc(GFP_ATOMIC, 1);
 578         if (!bio)
 579                 return -ENOMEM;
 580         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
 581         bio_get(bio);
 582         bio->bi_bdev = resume_bdev;
 583         bio->bi_end_io = end_io;
 584
 585         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
 586                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
 587                 error = -EFAULT;
 588                 goto Done;
 589         }
 590
 591         if (rw == WRITE)
 592                 bio_set_pages_dirty(bio);
 593
 594         atomic_set(&io_done, 1);
 595         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
 596         while (atomic_read(&io_done))
 597                 yield();
 598
 599  Done:
 600         bio_put(bio);
 601         return error;
 602 }
 603
 604 static int bio_read_page(pgoff_t page_off, void *page)
 605 {
 606         return submit(READ, page_off, page);
 607 }
 608
 609 static int bio_write_page(pgoff_t page_off, void *page)
 610 {
 611         return submit(WRITE, page_off, page);
 612 }
 613
 614 /*
 615  * Sanity check if this image makes sense with this kernel/swap context
 616  * I really don't think that it's foolproof but more than nothing..
 617  */
 618
 619 static const char *sanity_check(void)
 620 {
 621         dump_info();
 622         if (swsusp_info.version_code != LINUX_VERSION_CODE)
 623                 return "kernel version";
 624         if (swsusp_info.num_physpages != num_physpages)
 625                 return "memory size";
 626         if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
 627                 return "system type";
 628         if (strcmp(swsusp_info.uts.release,system_utsname.release))
 629                 return "kernel release";
 630         if (strcmp(swsusp_info.uts.version,system_utsname.version))
 631                 return "version";
 632         if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
 633                 return "machine";
 634 #if 0
 635         /* We can't use number of online CPUs when we use hotplug to remove them ;-))) */
 636         if (swsusp_info.cpus != num_possible_cpus())
 637                 return "number of cpus";
 638 #endif
 639         return NULL;
 640 }
 641
 642
 643 static int check_header(void)
 644 {
 645         const char *reason = NULL;
 646         int error;
 647
 648         if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
 649                 return error;
 650
 651         /* Is this same machine? */
 652         if ((reason = sanity_check())) {
 653                 printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
 654                 return -EPERM;
 655         }
 656         nr_copy_pages = swsusp_info.image_pages;
 657         return error;
 658 }
 659
 660 static int check_sig(void)
 661 {
 662         int error;
 663
 664         memset(&swsusp_header, 0, sizeof(swsusp_header));
 665         if ((error = bio_read_page(0, &swsusp_header)))
 666                 return error;
 667         if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 668                 memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 669
 670                 /*
 671                  * Reset swap signature now.
 672                  */
 673                 error = bio_write_page(0, &swsusp_header);
 674         } else {
 675                 return -EINVAL;
 676         }
 677         if (!error)
 678                 pr_debug("swsusp: Signature found, resuming\n");
 679         return error;
 680 }
 681
 682 /**
 683  *      data_read - Read image pages from swap.
 684  *
 685  *      You do not need to check for overlaps, check_pagedir()
 686  *      already did that.
 687  */
 688
 689 static int data_read(struct pbe *pblist)
 690 {
 691         struct pbe *p;
 692         int error = 0;
 693         int i = 0;
 694         int mod = swsusp_info.image_pages / 100;
 695
 696         if (!mod)
 697                 mod = 1;
 698
 699         printk("swsusp: Reading image data (%lu pages):     ",
 700                         swsusp_info.image_pages);
 701
 702         for_each_pbe (p, pblist) {
 703                 if (!(i % mod))
 704                         printk("\b\b\b\b%3d%%", i / mod);
 705
 706                 if ((error = bio_read_page(swp_offset(p->swap_address),
 707                                                 (void *)p->address)))
 708                         return error;
 709
 710                 i++;
 711         }
 712         printk("\b\b\b\bdone\n");
 713         return error;
 714 }
 715
 716 /**
 717  *      read_pagedir - Read page backup list pages from swap
 718  */
 719
 720 static int read_pagedir(struct pbe *pblist)
 721 {
 722         struct pbe *pbpage, *p;
 723         unsigned int i = 0;
 724         int error;
 725
 726         if (!pblist)
 727                 return -EFAULT;
 728
 729         printk("swsusp: Reading pagedir (%lu pages)\n",
 730                         swsusp_info.pagedir_pages);
 731
 732         for_each_pb_page (pbpage, pblist) {
 733                 unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
 734
 735                 error = -EFAULT;
 736                 if (offset) {
 737                         p = (pbpage + PB_PAGE_SKIP)->next;
 738                         error = bio_read_page(offset, (void *)pbpage);
 739                         (pbpage + PB_PAGE_SKIP)->next = p;
 740                 }
 741                 if (error)
 742                         break;
 743         }
 744
 745         if (!error)
 746                 BUG_ON(i != swsusp_info.pagedir_pages);
 747
 748         return error;
 749 }
 750
 751
 752 static int check_suspend_image(void)
 753 {
 754         int error = 0;
 755
 756         if ((error = check_sig()))
 757                 return error;
 758
 759         if ((error = check_header()))
 760                 return error;
 761
 762         return 0;
 763 }
 764
 765 static int read_suspend_image(void)
 766 {
 767         int error = 0;
 768         struct pbe *p;
 769
 770         if (!(p = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 0)))
 771                 return -ENOMEM;
 772
 773         if ((error = read_pagedir(p)))
 774                 return error;
 775         create_pbe_list(p, nr_copy_pages);
 776         mark_unsafe_pages(p);
 777         pagedir_nosave = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
 778         if (pagedir_nosave) {
 779                 create_pbe_list(pagedir_nosave, nr_copy_pages);
 780                 copy_page_backup_list(pagedir_nosave, p);
 781         }
 782         free_pagedir(p);
 783         if (!pagedir_nosave)
 784                 return -ENOMEM;
 785
 786         /* Allocate memory for the image and read the data from swap */
 787
 788         error = alloc_data_pages(pagedir_nosave, GFP_ATOMIC, 1);
 789
 790         if (!error)
 791                 error = data_read(pagedir_nosave);
 792
 793         return error;
 794 }
 795
 796 /**
 797  *      swsusp_check - Check for saved image in swap
 798  */
 799
 800 int swsusp_check(void)
 801 {
 802         int error;
 803
 804         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 805         if (!IS_ERR(resume_bdev)) {
 806                 set_blocksize(resume_bdev, PAGE_SIZE);
 807                 error = check_suspend_image();
 808                 if (error)
 809                     blkdev_put(resume_bdev);
 810         } else
 811                 error = PTR_ERR(resume_bdev);
 812
 813         if (!error)
 814                 pr_debug("swsusp: resume file found\n");
 815         else
 816                 pr_debug("swsusp: Error %d check for resume file\n", error);
 817         return error;
 818 }
 819
 820 /**
 821  *      swsusp_read - Read saved image from swap.
 822  */
 823
 824 int swsusp_read(void)
 825 {
 826         int error;
 827
 828         if (IS_ERR(resume_bdev)) {
 829                 pr_debug("swsusp: block device not initialised\n");
 830                 return PTR_ERR(resume_bdev);
 831         }
 832
 833         error = read_suspend_image();
 834         blkdev_put(resume_bdev);
 835
 836         if (!error)
 837                 pr_debug("swsusp: Reading resume file was successful\n");
 838         else
 839                 pr_debug("swsusp: Error %d resuming\n", error);
 840         return error;
 841 }
 842
 843 /**
 844  *      swsusp_close - close swap device.
 845  */
 846
 847 void swsusp_close(void)
 848 {
 849         if (IS_ERR(resume_bdev)) {
 850                 pr_debug("swsusp: block device not initialised\n");
 851                 return;
 852         }
 853
 854         blkdev_put(resume_bdev);
 855 }