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@ucw.cz> 8 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> 9 * 10 * This file is released under the GPLv2. 11 * 12 */ 13 14#include <linux/module.h> 15#include <linux/file.h> 16#include <linux/delay.h> 17#include <linux/bitops.h> 18#include <linux/genhd.h> 19#include <linux/device.h> 20#include <linux/buffer_head.h> 21#include <linux/bio.h> 22#include <linux/blkdev.h> 23#include <linux/swap.h> 24#include <linux/swapops.h> 25#include <linux/pm.h> 26#include <linux/slab.h> 27 28#include "power.h" 29 30#define SWSUSP_SIG "S1SUSPEND" 31 32/* 33 * The swap map is a data structure used for keeping track of each page 34 * written to a swap partition. It consists of many swap_map_page 35 * structures that contain each an array of MAP_PAGE_ENTRIES swap entries. 36 * These structures are stored on the swap and linked together with the 37 * help of the .next_swap member. 38 * 39 * The swap map is created during suspend. The swap map pages are 40 * allocated and populated one at a time, so we only need one memory 41 * page to set up the entire structure. 42 * 43 * During resume we also only need to use one swap_map_page structure 44 * at a time. 45 */ 46 47#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1) 48 49struct swap_map_page { 50 sector_t entries[MAP_PAGE_ENTRIES]; 51 sector_t next_swap; 52}; 53 54/** 55 * The swap_map_handle structure is used for handling swap in 56 * a file-alike way 57 */ 58 59struct swap_map_handle { 60 struct swap_map_page *cur; 61 sector_t cur_swap; 62 sector_t first_sector; 63 unsigned int k; 64}; 65 66struct swsusp_header { 67 char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)]; 68 sector_t image; 69 unsigned int flags; /* Flags to pass to the "boot" kernel */ 70 char orig_sig[10]; 71 char sig[10]; 72} __attribute__((packed)); 73 74static struct swsusp_header *swsusp_header; 75 76/** 77 * The following functions are used for tracing the allocated 78 * swap pages, so that they can be freed in case of an error. 79 */ 80 81struct swsusp_extent { 82 struct rb_node node; 83 unsigned long start; 84 unsigned long end; 85}; 86 87static struct rb_root swsusp_extents = RB_ROOT; 88 89static int swsusp_extents_insert(unsigned long swap_offset) 90{ 91 struct rb_node **new = &(swsusp_extents.rb_node); 92 struct rb_node *parent = NULL; 93 struct swsusp_extent *ext; 94 95 /* Figure out where to put the new node */ 96 while (*new) { 97 ext = container_of(*new, struct swsusp_extent, node); 98 parent = *new; 99 if (swap_offset < ext->start) { 100 /* Try to merge */ 101 if (swap_offset == ext->start - 1) { 102 ext->start--; 103 return 0; 104 } 105 new = &((*new)->rb_left); 106 } else if (swap_offset > ext->end) { 107 /* Try to merge */ 108 if (swap_offset == ext->end + 1) { 109 ext->end++; 110 return 0; 111 } 112 new = &((*new)->rb_right); 113 } else { 114 /* It already is in the tree */ 115 return -EINVAL; 116 } 117 } 118 /* Add the new node and rebalance the tree. */ 119 ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL); 120 if (!ext) 121 return -ENOMEM; 122 123 ext->start = swap_offset; 124 ext->end = swap_offset; 125 rb_link_node(&ext->node, parent, new); 126 rb_insert_color(&ext->node, &swsusp_extents); 127 return 0; 128} 129 130/** 131 * alloc_swapdev_block - allocate a swap page and register that it has 132 * been allocated, so that it can be freed in case of an error. 133 */ 134 135sector_t alloc_swapdev_block(int swap) 136{ 137 unsigned long offset; 138 139 offset = swp_offset(get_swap_page_of_type(swap)); 140 if (offset) { 141 if (swsusp_extents_insert(offset)) 142 swap_free(swp_entry(swap, offset)); 143 else 144 return swapdev_block(swap, offset); 145 } 146 return 0; 147} 148 149/** 150 * free_all_swap_pages - free swap pages allocated for saving image data. 151 * It also frees the extents used to register which swap entries had been 152 * allocated. 153 */ 154 155void free_all_swap_pages(int swap) 156{ 157 struct rb_node *node; 158 159 while ((node = swsusp_extents.rb_node)) { 160 struct swsusp_extent *ext; 161 unsigned long offset; 162 163 ext = container_of(node, struct swsusp_extent, node); 164 rb_erase(node, &swsusp_extents); 165 for (offset = ext->start; offset <= ext->end; offset++) 166 swap_free(swp_entry(swap, offset)); 167 168 kfree(ext); 169 } 170} 171 172int swsusp_swap_in_use(void) 173{ 174 return (swsusp_extents.rb_node != NULL); 175} 176 177/* 178 * General things 179 */ 180 181static unsigned short root_swap = 0xffff; 182struct block_device *hib_resume_bdev; 183 184/* 185 * Saving part 186 */ 187 188static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags) 189{ 190 int error; 191 192 hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL); 193 if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) || 194 !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) { 195 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10); 196 memcpy(swsusp_header->sig,SWSUSP_SIG, 10); 197 swsusp_header->image = handle->first_sector; 198 swsusp_header->flags = flags; 199 error = hib_bio_write_page(swsusp_resume_block, 200 swsusp_header, NULL); 201 } else { 202 printk(KERN_ERR "PM: Swap header not found!\n"); 203 error = -ENODEV; 204 } 205 return error; 206} 207 208/** 209 * swsusp_swap_check - check if the resume device is a swap device 210 * and get its index (if so) 211 * 212 * This is called before saving image 213 */ 214static int swsusp_swap_check(void) 215{ 216 int res; 217 218 res = swap_type_of(swsusp_resume_device, swsusp_resume_block, 219 &hib_resume_bdev); 220 if (res < 0) 221 return res; 222 223 root_swap = res; 224 res = blkdev_get(hib_resume_bdev, FMODE_WRITE); 225 if (res) 226 return res; 227 228 res = set_blocksize(hib_resume_bdev, PAGE_SIZE); 229 if (res < 0) 230 blkdev_put(hib_resume_bdev, FMODE_WRITE); 231 232 return res; 233} 234 235/** 236 * write_page - Write one page to given swap location. 237 * @buf: Address we're writing. 238 * @offset: Offset of the swap page we're writing to. 239 * @bio_chain: Link the next write BIO here 240 */ 241 242static int write_page(void *buf, sector_t offset, struct bio **bio_chain) 243{ 244 void *src; 245 246 if (!offset) 247 return -ENOSPC; 248 249 if (bio_chain) { 250 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH); 251 if (src) { 252 memcpy(src, buf, PAGE_SIZE); 253 } else { 254 WARN_ON_ONCE(1); 255 bio_chain = NULL; /* Go synchronous */ 256 src = buf; 257 } 258 } else { 259 src = buf; 260 } 261 return hib_bio_write_page(offset, src, bio_chain); 262} 263 264static void release_swap_writer(struct swap_map_handle *handle) 265{ 266 if (handle->cur) 267 free_page((unsigned long)handle->cur); 268 handle->cur = NULL; 269} 270 271static int get_swap_writer(struct swap_map_handle *handle) 272{ 273 int ret; 274 275 ret = swsusp_swap_check(); 276 if (ret) { 277 if (ret != -ENOSPC) 278 printk(KERN_ERR "PM: Cannot find swap device, try " 279 "swapon -a.\n"); 280 return ret; 281 } 282 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); 283 if (!handle->cur) { 284 ret = -ENOMEM; 285 goto err_close; 286 } 287 handle->cur_swap = alloc_swapdev_block(root_swap); 288 if (!handle->cur_swap) { 289 ret = -ENOSPC; 290 goto err_rel; 291 } 292 handle->k = 0; 293 handle->first_sector = handle->cur_swap; 294 return 0; 295err_rel: 296 release_swap_writer(handle); 297err_close: 298 swsusp_close(FMODE_WRITE); 299 return ret; 300} 301 302static int swap_write_page(struct swap_map_handle *handle, void *buf, 303 struct bio **bio_chain) 304{ 305 int error = 0; 306 sector_t offset; 307 308 if (!handle->cur) 309 return -EINVAL; 310 offset = alloc_swapdev_block(root_swap); 311 error = write_page(buf, offset, bio_chain); 312 if (error) 313 return error; 314 handle->cur->entries[handle->k++] = offset; 315 if (handle->k >= MAP_PAGE_ENTRIES) { 316 error = hib_wait_on_bio_chain(bio_chain); 317 if (error) 318 goto out; 319 offset = alloc_swapdev_block(root_swap); 320 if (!offset) 321 return -ENOSPC; 322 handle->cur->next_swap = offset; 323 error = write_page(handle->cur, handle->cur_swap, NULL); 324 if (error) 325 goto out; 326 memset(handle->cur, 0, PAGE_SIZE); 327 handle->cur_swap = offset; 328 handle->k = 0; 329 } 330 out: 331 return error; 332} 333 334static int flush_swap_writer(struct swap_map_handle *handle) 335{ 336 if (handle->cur && handle->cur_swap) 337 return write_page(handle->cur, handle->cur_swap, NULL); 338 else 339 return -EINVAL; 340} 341 342static int swap_writer_finish(struct swap_map_handle *handle, 343 unsigned int flags, int error) 344{ 345 if (!error) { 346 flush_swap_writer(handle); 347 printk(KERN_INFO "PM: S"); 348 error = mark_swapfiles(handle, flags); 349 printk("|\n"); 350 } 351 352 if (error) 353 free_all_swap_pages(root_swap); 354 release_swap_writer(handle); 355 swsusp_close(FMODE_WRITE); 356 357 return error; 358} 359 360/** 361 * save_image - save the suspend image data 362 */ 363 364static int save_image(struct swap_map_handle *handle, 365 struct snapshot_handle *snapshot, 366 unsigned int nr_to_write) 367{ 368 unsigned int m; 369 int ret; 370 int nr_pages; 371 int err2; 372 struct bio *bio; 373 struct timeval start; 374 struct timeval stop; 375 376 printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ", 377 nr_to_write); 378 m = nr_to_write / 100; 379 if (!m) 380 m = 1; 381 nr_pages = 0; 382 bio = NULL; 383 do_gettimeofday(&start); 384 while (1) { 385 ret = snapshot_read_next(snapshot); 386 if (ret <= 0) 387 break; 388 ret = swap_write_page(handle, data_of(*snapshot), &bio); 389 if (ret) 390 break; 391 if (!(nr_pages % m)) 392 printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m); 393 nr_pages++; 394 } 395 err2 = hib_wait_on_bio_chain(&bio); 396 do_gettimeofday(&stop); 397 if (!ret) 398 ret = err2; 399 if (!ret) 400 printk(KERN_CONT "\b\b\b\bdone\n"); 401 else 402 printk(KERN_CONT "\n"); 403 swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); 404 return ret; 405} 406 407/** 408 * enough_swap - Make sure we have enough swap to save the image. 409 * 410 * Returns TRUE or FALSE after checking the total amount of swap 411 * space avaiable from the resume partition. 412 */ 413 414static int enough_swap(unsigned int nr_pages) 415{ 416 unsigned int free_swap = count_swap_pages(root_swap, 1); 417 418 pr_debug("PM: Free swap pages: %u\n", free_swap); 419 return free_swap > nr_pages + PAGES_FOR_IO; 420} 421 422/** 423 * swsusp_write - Write entire image and metadata. 424 * @flags: flags to pass to the "boot" kernel in the image header 425 * 426 * It is important _NOT_ to umount filesystems at this point. We want 427 * them synced (in case something goes wrong) but we DO not want to mark 428 * filesystem clean: it is not. (And it does not matter, if we resume 429 * correctly, we'll mark system clean, anyway.) 430 */ 431 432int swsusp_write(unsigned int flags) 433{ 434 struct swap_map_handle handle; 435 struct snapshot_handle snapshot; 436 struct swsusp_info *header; 437 unsigned long pages; 438 int error; 439 440 pages = snapshot_get_image_size(); 441 error = get_swap_writer(&handle); 442 if (error) { 443 printk(KERN_ERR "PM: Cannot get swap writer\n"); 444 return error; 445 } 446 if (!enough_swap(pages)) { 447 printk(KERN_ERR "PM: Not enough free swap\n"); 448 error = -ENOSPC; 449 goto out_finish; 450 } 451 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 452 error = snapshot_read_next(&snapshot); 453 if (error < PAGE_SIZE) { 454 if (error >= 0) 455 error = -EFAULT; 456 457 goto out_finish; 458 } 459 header = (struct swsusp_info *)data_of(snapshot); 460 error = swap_write_page(&handle, header, NULL); 461 if (!error) 462 error = save_image(&handle, &snapshot, pages - 1); 463out_finish: 464 error = swap_writer_finish(&handle, flags, error); 465 return error; 466} 467 468/** 469 * The following functions allow us to read data using a swap map 470 * in a file-alike way 471 */ 472 473static void release_swap_reader(struct swap_map_handle *handle) 474{ 475 if (handle->cur) 476 free_page((unsigned long)handle->cur); 477 handle->cur = NULL; 478} 479 480static int get_swap_reader(struct swap_map_handle *handle, 481 unsigned int *flags_p) 482{ 483 int error; 484 485 *flags_p = swsusp_header->flags; 486 487 if (!swsusp_header->image) /* how can this happen? */ 488 return -EINVAL; 489 490 handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH); 491 if (!handle->cur) 492 return -ENOMEM; 493 494 error = hib_bio_read_page(swsusp_header->image, handle->cur, NULL); 495 if (error) { 496 release_swap_reader(handle); 497 return error; 498 } 499 handle->k = 0; 500 return 0; 501} 502 503static int swap_read_page(struct swap_map_handle *handle, void *buf, 504 struct bio **bio_chain) 505{ 506 sector_t offset; 507 int error; 508 509 if (!handle->cur) 510 return -EINVAL; 511 offset = handle->cur->entries[handle->k]; 512 if (!offset) 513 return -EFAULT; 514 error = hib_bio_read_page(offset, buf, bio_chain); 515 if (error) 516 return error; 517 if (++handle->k >= MAP_PAGE_ENTRIES) { 518 error = hib_wait_on_bio_chain(bio_chain); 519 handle->k = 0; 520 offset = handle->cur->next_swap; 521 if (!offset) 522 release_swap_reader(handle); 523 else if (!error) 524 error = hib_bio_read_page(offset, handle->cur, NULL); 525 } 526 return error; 527} 528 529static int swap_reader_finish(struct swap_map_handle *handle) 530{ 531 release_swap_reader(handle); 532 533 return 0; 534} 535 536/** 537 * load_image - load the image using the swap map handle 538 * @handle and the snapshot handle @snapshot 539 * (assume there are @nr_pages pages to load) 540 */ 541 542static int load_image(struct swap_map_handle *handle, 543 struct snapshot_handle *snapshot, 544 unsigned int nr_to_read) 545{ 546 unsigned int m; 547 int error = 0; 548 struct timeval start; 549 struct timeval stop; 550 struct bio *bio; 551 int err2; 552 unsigned nr_pages; 553 554 printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ", 555 nr_to_read); 556 m = nr_to_read / 100; 557 if (!m) 558 m = 1; 559 nr_pages = 0; 560 bio = NULL; 561 do_gettimeofday(&start); 562 for ( ; ; ) { 563 error = snapshot_write_next(snapshot); 564 if (error <= 0) 565 break; 566 error = swap_read_page(handle, data_of(*snapshot), &bio); 567 if (error) 568 break; 569 if (snapshot->sync_read) 570 error = hib_wait_on_bio_chain(&bio); 571 if (error) 572 break; 573 if (!(nr_pages % m)) 574 printk("\b\b\b\b%3d%%", nr_pages / m); 575 nr_pages++; 576 } 577 err2 = hib_wait_on_bio_chain(&bio); 578 do_gettimeofday(&stop); 579 if (!error) 580 error = err2; 581 if (!error) { 582 printk("\b\b\b\bdone\n"); 583 snapshot_write_finalize(snapshot); 584 if (!snapshot_image_loaded(snapshot)) 585 error = -ENODATA; 586 } else 587 printk("\n"); 588 swsusp_show_speed(&start, &stop, nr_to_read, "Read"); 589 return error; 590} 591 592/** 593 * swsusp_read - read the hibernation image. 594 * @flags_p: flags passed by the "frozen" kernel in the image header should 595 * be written into this memeory location 596 */ 597 598int swsusp_read(unsigned int *flags_p) 599{ 600 int error; 601 struct swap_map_handle handle; 602 struct snapshot_handle snapshot; 603 struct swsusp_info *header; 604 605 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 606 error = snapshot_write_next(&snapshot); 607 if (error < PAGE_SIZE) 608 return error < 0 ? error : -EFAULT; 609 header = (struct swsusp_info *)data_of(snapshot); 610 error = get_swap_reader(&handle, flags_p); 611 if (error) 612 goto end; 613 if (!error) 614 error = swap_read_page(&handle, header, NULL); 615 if (!error) 616 error = load_image(&handle, &snapshot, header->pages - 1); 617 swap_reader_finish(&handle); 618end: 619 if (!error) 620 pr_debug("PM: Image successfully loaded\n"); 621 else 622 pr_debug("PM: Error %d resuming\n", error); 623 return error; 624} 625 626/** 627 * swsusp_check - Check for swsusp signature in the resume device 628 */ 629 630int swsusp_check(void) 631{ 632 int error; 633 634 hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); 635 if (!IS_ERR(hib_resume_bdev)) { 636 set_blocksize(hib_resume_bdev, PAGE_SIZE); 637 memset(swsusp_header, 0, PAGE_SIZE); 638 error = hib_bio_read_page(swsusp_resume_block, 639 swsusp_header, NULL); 640 if (error) 641 goto put; 642 643 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) { 644 memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); 645 /* Reset swap signature now */ 646 error = hib_bio_write_page(swsusp_resume_block, 647 swsusp_header, NULL); 648 } else { 649 error = -EINVAL; 650 } 651 652put: 653 if (error) 654 blkdev_put(hib_resume_bdev, FMODE_READ); 655 else 656 pr_debug("PM: Signature found, resuming\n"); 657 } else { 658 error = PTR_ERR(hib_resume_bdev); 659 } 660 661 if (error) 662 pr_debug("PM: Error %d checking image file\n", error); 663 664 return error; 665} 666 667/** 668 * swsusp_close - close swap device. 669 */ 670 671void swsusp_close(fmode_t mode) 672{ 673 if (IS_ERR(hib_resume_bdev)) { 674 pr_debug("PM: Image device not initialised\n"); 675 return; 676 } 677 678 blkdev_put(hib_resume_bdev, mode); 679} 680 681static int swsusp_header_init(void) 682{ 683 swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL); 684 if (!swsusp_header) 685 panic("Could not allocate memory for swsusp_header\n"); 686 return 0; 687} 688 689core_initcall(swsusp_header_init); 690