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/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 static 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, aligned(PAGE_SIZE))) 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_ATOMIC, 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 static void show_speed(struct timeval *start, struct timeval *stop,
 137                         unsigned nr_pages, char *msg)
 138 {
 139         s64 elapsed_centisecs64;
 140         int centisecs;
 141         int k;
 142         int kps;
 143
 144         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 145         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 146         centisecs = elapsed_centisecs64;
 147         if (centisecs == 0)
 148                 centisecs = 1;  /* avoid div-by-zero */
 149         k = nr_pages * (PAGE_SIZE / 1024);
 150         kps = (k * 100) / centisecs;
 151         printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
 152                         centisecs / 100, centisecs % 100,
 153                         kps / 1000, (kps % 1000) / 10);
 154 }
 155
 156 /*
 157  * Saving part
 158  */
 159
 160 static int mark_swapfiles(sector_t start)
 161 {
 162         int error;
 163
 164         bio_read_page(swsusp_resume_block, &swsusp_header, NULL);
 165         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
 166             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
 167                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 168                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 169                 swsusp_header.image = start;
 170                 error = bio_write_page(swsusp_resume_block,
 171                                         &swsusp_header, NULL);
 172         } else {
 173                 printk(KERN_ERR "swsusp: Swap header not found!\n");
 174                 error = -ENODEV;
 175         }
 176         return error;
 177 }
 178
 179 /**
 180  *      swsusp_swap_check - check if the resume device is a swap device
 181  *      and get its index (if so)
 182  */
 183
 184 static int swsusp_swap_check(void) /* This is called before saving image */
 185 {
 186         int res;
 187
 188         res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
 189         if (res < 0)
 190                 return res;
 191
 192         root_swap = res;
 193         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_WRITE);
 194         if (IS_ERR(resume_bdev))
 195                 return PTR_ERR(resume_bdev);
 196
 197         res = set_blocksize(resume_bdev, PAGE_SIZE);
 198         if (res < 0)
 199                 blkdev_put(resume_bdev);
 200
 201         return res;
 202 }
 203
 204 /**
 205  *      write_page - Write one page to given swap location.
 206  *      @buf:           Address we're writing.
 207  *      @offset:        Offset of the swap page we're writing to.
 208  *      @bio_chain:     Link the next write BIO here
 209  */
 210
 211 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
 212 {
 213         void *src;
 214
 215         if (!offset)
 216                 return -ENOSPC;
 217
 218         if (bio_chain) {
 219                 src = (void *)__get_free_page(GFP_ATOMIC);
 220                 if (src) {
 221                         memcpy(src, buf, PAGE_SIZE);
 222                 } else {
 223                         WARN_ON_ONCE(1);
 224                         bio_chain = NULL;       /* Go synchronous */
 225                         src = buf;
 226                 }
 227         } else {
 228                 src = buf;
 229         }
 230         return bio_write_page(offset, src, bio_chain);
 231 }
 232
 233 /*
 234  *      The swap map is a data structure used for keeping track of each page
 235  *      written to a swap partition.  It consists of many swap_map_page
 236  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 237  *      These structures are stored on the swap and linked together with the
 238  *      help of the .next_swap member.
 239  *
 240  *      The swap map is created during suspend.  The swap map pages are
 241  *      allocated and populated one at a time, so we only need one memory
 242  *      page to set up the entire structure.
 243  *
 244  *      During resume we also only need to use one swap_map_page structure
 245  *      at a time.
 246  */
 247
 248 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
 249
 250 struct swap_map_page {
 251         sector_t entries[MAP_PAGE_ENTRIES];
 252         sector_t next_swap;
 253 };
 254
 255 /**
 256  *      The swap_map_handle structure is used for handling swap in
 257  *      a file-alike way
 258  */
 259
 260 struct swap_map_handle {
 261         struct swap_map_page *cur;
 262         sector_t cur_swap;
 263         struct bitmap_page *bitmap;
 264         unsigned int k;
 265 };
 266
 267 static void release_swap_writer(struct swap_map_handle *handle)
 268 {
 269         if (handle->cur)
 270                 free_page((unsigned long)handle->cur);
 271         handle->cur = NULL;
 272         if (handle->bitmap)
 273                 free_bitmap(handle->bitmap);
 274         handle->bitmap = NULL;
 275 }
 276
 277 static int get_swap_writer(struct swap_map_handle *handle)
 278 {
 279         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 280         if (!handle->cur)
 281                 return -ENOMEM;
 282         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 283         if (!handle->bitmap) {
 284                 release_swap_writer(handle);
 285                 return -ENOMEM;
 286         }
 287         handle->cur_swap = alloc_swapdev_block(root_swap, handle->bitmap);
 288         if (!handle->cur_swap) {
 289                 release_swap_writer(handle);
 290                 return -ENOSPC;
 291         }
 292         handle->k = 0;
 293         return 0;
 294 }
 295
 296 static int swap_write_page(struct swap_map_handle *handle, void *buf,
 297                                 struct bio **bio_chain)
 298 {
 299         int error = 0;
 300         sector_t offset;
 301
 302         if (!handle->cur)
 303                 return -EINVAL;
 304         offset = alloc_swapdev_block(root_swap, handle->bitmap);
 305         error = write_page(buf, offset, bio_chain);
 306         if (error)
 307                 return error;
 308         handle->cur->entries[handle->k++] = offset;
 309         if (handle->k >= MAP_PAGE_ENTRIES) {
 310                 error = wait_on_bio_chain(bio_chain);
 311                 if (error)
 312                         goto out;
 313                 offset = alloc_swapdev_block(root_swap, handle->bitmap);
 314                 if (!offset)
 315                         return -ENOSPC;
 316                 handle->cur->next_swap = offset;
 317                 error = write_page(handle->cur, handle->cur_swap, NULL);
 318                 if (error)
 319                         goto out;
 320                 memset(handle->cur, 0, PAGE_SIZE);
 321                 handle->cur_swap = offset;
 322                 handle->k = 0;
 323         }
 324 out:
 325         return error;
 326 }
 327
 328 static int flush_swap_writer(struct swap_map_handle *handle)
 329 {
 330         if (handle->cur && handle->cur_swap)
 331                 return write_page(handle->cur, handle->cur_swap, NULL);
 332         else
 333                 return -EINVAL;
 334 }
 335
 336 /**
 337  *      save_image - save the suspend image data
 338  */
 339
 340 static int save_image(struct swap_map_handle *handle,
 341                       struct snapshot_handle *snapshot,
 342                       unsigned int nr_to_write)
 343 {
 344         unsigned int m;
 345         int ret;
 346         int error = 0;
 347         int nr_pages;
 348         int err2;
 349         struct bio *bio;
 350         struct timeval start;
 351         struct timeval stop;
 352
 353         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 354         m = nr_to_write / 100;
 355         if (!m)
 356                 m = 1;
 357         nr_pages = 0;
 358         bio = NULL;
 359         do_gettimeofday(&start);
 360         do {
 361                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 362                 if (ret > 0) {
 363                         error = swap_write_page(handle, data_of(*snapshot),
 364                                                 &bio);
 365                         if (error)
 366                                 break;
 367                         if (!(nr_pages % m))
 368                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 369                         nr_pages++;
 370                 }
 371         } while (ret > 0);
 372         err2 = wait_on_bio_chain(&bio);
 373         do_gettimeofday(&stop);
 374         if (!error)
 375                 error = err2;
 376         if (!error)
 377                 printk("\b\b\b\bdone\n");
 378         show_speed(&start, &stop, nr_to_write, "Wrote");
 379         return error;
 380 }
 381
 382 /**
 383  *      enough_swap - Make sure we have enough swap to save the image.
 384  *
 385  *      Returns TRUE or FALSE after checking the total amount of swap
 386  *      space avaiable from the resume partition.
 387  */
 388
 389 static int enough_swap(unsigned int nr_pages)
 390 {
 391         unsigned int free_swap = count_swap_pages(root_swap, 1);
 392
 393         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 394         return free_swap > nr_pages + PAGES_FOR_IO;
 395 }
 396
 397 /**
 398  *      swsusp_write - Write entire image and metadata.
 399  *
 400  *      It is important _NOT_ to umount filesystems at this point. We want
 401  *      them synced (in case something goes wrong) but we DO not want to mark
 402  *      filesystem clean: it is not. (And it does not matter, if we resume
 403  *      correctly, we'll mark system clean, anyway.)
 404  */
 405
 406 int swsusp_write(void)
 407 {
 408         struct swap_map_handle handle;
 409         struct snapshot_handle snapshot;
 410         struct swsusp_info *header;
 411         int error;
 412
 413         error = swsusp_swap_check();
 414         if (error) {
 415                 printk(KERN_ERR "swsusp: Cannot find swap device, try "
 416                                 "swapon -a.\n");
 417                 return error;
 418         }
 419         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 420         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 421         if (error < PAGE_SIZE) {
 422                 if (error >= 0)
 423                         error = -EFAULT;
 424
 425                 goto out;
 426         }
 427         header = (struct swsusp_info *)data_of(snapshot);
 428         if (!enough_swap(header->pages)) {
 429                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 430                 error = -ENOSPC;
 431                 goto out;
 432         }
 433         error = get_swap_writer(&handle);
 434         if (!error) {
 435                 sector_t start = handle.cur_swap;
 436
 437                 error = swap_write_page(&handle, header, NULL);
 438                 if (!error)
 439                         error = save_image(&handle, &snapshot,
 440                                         header->pages - 1);
 441
 442                 if (!error) {
 443                         flush_swap_writer(&handle);
 444                         printk("S");
 445                         error = mark_swapfiles(start);
 446                         printk("|\n");
 447                 }
 448         }
 449         if (error)
 450                 free_all_swap_pages(root_swap, handle.bitmap);
 451         release_swap_writer(&handle);
 452 out:
 453         swsusp_close();
 454         return error;
 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, sector_t start)
 470 {
 471         int error;
 472
 473         if (!start)
 474                 return -EINVAL;
 475
 476         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
 477         if (!handle->cur)
 478                 return -ENOMEM;
 479
 480         error = bio_read_page(start, handle->cur, NULL);
 481         if (error) {
 482                 release_swap_reader(handle);
 483                 return error;
 484         }
 485         handle->k = 0;
 486         return 0;
 487 }
 488
 489 static int swap_read_page(struct swap_map_handle *handle, void *buf,
 490                                 struct bio **bio_chain)
 491 {
 492         sector_t offset;
 493         int error;
 494
 495         if (!handle->cur)
 496                 return -EINVAL;
 497         offset = handle->cur->entries[handle->k];
 498         if (!offset)
 499                 return -EFAULT;
 500         error = bio_read_page(offset, buf, bio_chain);
 501         if (error)
 502                 return error;
 503         if (++handle->k >= MAP_PAGE_ENTRIES) {
 504                 error = wait_on_bio_chain(bio_chain);
 505                 handle->k = 0;
 506                 offset = handle->cur->next_swap;
 507                 if (!offset)
 508                         release_swap_reader(handle);
 509                 else if (!error)
 510                         error = bio_read_page(offset, handle->cur, NULL);
 511         }
 512         return error;
 513 }
 514
 515 /**
 516  *      load_image - load the image using the swap map handle
 517  *      @handle and the snapshot handle @snapshot
 518  *      (assume there are @nr_pages pages to load)
 519  */
 520
 521 static int load_image(struct swap_map_handle *handle,
 522                       struct snapshot_handle *snapshot,
 523                       unsigned int nr_to_read)
 524 {
 525         unsigned int m;
 526         int error = 0;
 527         struct timeval start;
 528         struct timeval stop;
 529         struct bio *bio;
 530         int err2;
 531         unsigned nr_pages;
 532
 533         printk("Loading image data pages (%u pages) ...     ", nr_to_read);
 534         m = nr_to_read / 100;
 535         if (!m)
 536                 m = 1;
 537         nr_pages = 0;
 538         bio = NULL;
 539         do_gettimeofday(&start);
 540         for ( ; ; ) {
 541                 error = snapshot_write_next(snapshot, PAGE_SIZE);
 542                 if (error <= 0)
 543                         break;
 544                 error = swap_read_page(handle, data_of(*snapshot), &bio);
 545                 if (error)
 546                         break;
 547                 if (snapshot->sync_read)
 548                         error = wait_on_bio_chain(&bio);
 549                 if (error)
 550                         break;
 551                 if (!(nr_pages % m))
 552                         printk("\b\b\b\b%3d%%", nr_pages / m);
 553                 nr_pages++;
 554         }
 555         err2 = wait_on_bio_chain(&bio);
 556         do_gettimeofday(&stop);
 557         if (!error)
 558                 error = err2;
 559         if (!error) {
 560                 printk("\b\b\b\bdone\n");
 561                 snapshot_free_unused_memory(snapshot);
 562                 if (!snapshot_image_loaded(snapshot))
 563                         error = -ENODATA;
 564         }
 565         show_speed(&start, &stop, nr_to_read, "Read");
 566         return error;
 567 }
 568
 569 int swsusp_read(void)
 570 {
 571         int error;
 572         struct swap_map_handle handle;
 573         struct snapshot_handle snapshot;
 574         struct swsusp_info *header;
 575
 576         if (IS_ERR(resume_bdev)) {
 577                 pr_debug("swsusp: block device not initialised\n");
 578                 return PTR_ERR(resume_bdev);
 579         }
 580
 581         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 582         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 583         if (error < PAGE_SIZE)
 584                 return error < 0 ? error : -EFAULT;
 585         header = (struct swsusp_info *)data_of(snapshot);
 586         error = get_swap_reader(&handle, swsusp_header.image);
 587         if (!error)
 588                 error = swap_read_page(&handle, header, NULL);
 589         if (!error)
 590                 error = load_image(&handle, &snapshot, header->pages - 1);
 591         release_swap_reader(&handle);
 592
 593         blkdev_put(resume_bdev);
 594
 595         if (!error)
 596                 pr_debug("swsusp: Reading resume file was successful\n");
 597         else
 598                 pr_debug("swsusp: Error %d resuming\n", error);
 599         return error;
 600 }
 601
 602 /**
 603  *      swsusp_check - Check for swsusp signature in the resume device
 604  */
 605
 606 int swsusp_check(void)
 607 {
 608         int error;
 609
 610         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 611         if (!IS_ERR(resume_bdev)) {
 612                 set_blocksize(resume_bdev, PAGE_SIZE);
 613                 memset(&swsusp_header, 0, sizeof(swsusp_header));
 614                 error = bio_read_page(swsusp_resume_block,
 615                                         &swsusp_header, NULL);
 616                 if (error)
 617                         return error;
 618
 619                 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 620                         memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 621                         /* Reset swap signature now */
 622                         error = bio_write_page(swsusp_resume_block,
 623                                                 &swsusp_header, NULL);
 624                 } else {
 625                         return -EINVAL;
 626                 }
 627                 if (error)
 628                         blkdev_put(resume_bdev);
 629                 else
 630                         pr_debug("swsusp: Signature found, resuming\n");
 631         } else {
 632                 error = PTR_ERR(resume_bdev);
 633         }
 634
 635         if (error)
 636                 pr_debug("swsusp: Error %d check for resume file\n", error);
 637
 638         return error;
 639 }
 640
 641 /**
 642  *      swsusp_close - close swap device.
 643  */
 644
 645 void swsusp_close(void)
 646 {
 647         if (IS_ERR(resume_bdev)) {
 648                 pr_debug("swsusp: block device not initialised\n");
 649                 return;
 650         }
 651
 652         blkdev_put(resume_bdev);
 653 }