1 /* 2 * linux/kernel/power/swap.c 3 * 4 * This file provides functions for reading the suspend image from 5 * and writing it to a swap partition. 6 * 7 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz> 8 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> 9 * 10 * This file is released under the GPLv2. 11 * 12 */ 13 14 #include <linux/module.h> 15 #include <linux/smp_lock.h> 16 #include <linux/file.h> 17 #include <linux/utsname.h> 18 #include <linux/version.h> 19 #include <linux/delay.h> 20 #include <linux/bitops.h> 21 #include <linux/genhd.h> 22 #include <linux/device.h> 23 #include <linux/buffer_head.h> 24 #include <linux/bio.h> 25 #include <linux/blkdev.h> 26 #include <linux/swap.h> 27 #include <linux/swapops.h> 28 #include <linux/pm.h> 29 30 #include "power.h" 31 32 extern char resume_file[]; 33 34 #define SWSUSP_SIG "S1SUSPEND" 35 36 struct swsusp_header { 37 char reserved[PAGE_SIZE - 20 - sizeof(sector_t)]; 38 sector_t image; 39 char orig_sig[10]; 40 char sig[10]; 41 } __attribute__((packed)); 42 43 static struct swsusp_header *swsusp_header; 44 45 /* 46 * General things 47 */ 48 49 static unsigned short root_swap = 0xffff; 50 static struct block_device *resume_bdev; 51 52 /** 53 * submit - submit BIO request. 54 * @rw: READ or WRITE. 55 * @off physical offset of page. 56 * @page: page we're reading or writing. 57 * @bio_chain: list of pending biod (for async reading) 58 * 59 * Straight from the textbook - allocate and initialize the bio. 60 * If we're reading, make sure the page is marked as dirty. 61 * Then submit it and, if @bio_chain == NULL, wait. 62 */ 63 static int submit(int rw, pgoff_t page_off, struct page *page, 64 struct bio **bio_chain) 65 { 66 struct bio *bio; 67 68 bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1); 69 if (!bio) 70 return -ENOMEM; 71 bio->bi_sector = page_off * (PAGE_SIZE >> 9); 72 bio->bi_bdev = resume_bdev; 73 bio->bi_end_io = end_swap_bio_read; 74 75 if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { 76 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off); 77 bio_put(bio); 78 return -EFAULT; 79 } 80 81 lock_page(page); 82 bio_get(bio); 83 84 if (bio_chain == NULL) { 85 submit_bio(rw | (1 << BIO_RW_SYNC), bio); 86 wait_on_page_locked(page); 87 if (rw == READ) 88 bio_set_pages_dirty(bio); 89 bio_put(bio); 90 } else { 91 if (rw == READ) 92 get_page(page); /* These pages are freed later */ 93 bio->bi_private = *bio_chain; 94 *bio_chain = bio; 95 submit_bio(rw | (1 << BIO_RW_SYNC), bio); 96 } 97 return 0; 98 } 99 100 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain) 101 { 102 return submit(READ, page_off, virt_to_page(addr), bio_chain); 103 } 104 105 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain) 106 { 107 return submit(WRITE, page_off, virt_to_page(addr), bio_chain); 108 } 109 110 static int wait_on_bio_chain(struct bio **bio_chain) 111 { 112 struct bio *bio; 113 struct bio *next_bio; 114 int ret = 0; 115 116 if (bio_chain == NULL) 117 return 0; 118 119 bio = *bio_chain; 120 if (bio == NULL) 121 return 0; 122 while (bio) { 123 struct page *page; 124 125 next_bio = bio->bi_private; 126 page = bio->bi_io_vec[0].bv_page; 127 wait_on_page_locked(page); 128 if (!PageUptodate(page) || PageError(page)) 129 ret = -EIO; 130 put_page(page); 131 bio_put(bio); 132 bio = next_bio; 133 } 134 *bio_chain = NULL; 135 return ret; 136 } 137 138 /* 139 * Saving part 140 */ 141 142 static int mark_swapfiles(sector_t start) 143 { 144 int error; 145 146 bio_read_page(swsusp_resume_block, swsusp_header, NULL); 147 if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) || 148 !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) { 149 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10); 150 memcpy(swsusp_header->sig,SWSUSP_SIG, 10); 151 swsusp_header->image = start; 152 error = bio_write_page(swsusp_resume_block, 153 swsusp_header, NULL); 154 } else { 155 printk(KERN_ERR "swsusp: Swap header not found!\n"); 156 error = -ENODEV; 157 } 158 return error; 159 } 160 161 /** 162 * swsusp_swap_check - check if the resume device is a swap device 163 * and get its index (if so) 164 */ 165 166 static int swsusp_swap_check(void) /* This is called before saving image */ 167 { 168 int res; 169 170 res = swap_type_of(swsusp_resume_device, swsusp_resume_block, 171 &resume_bdev); 172 if (res < 0) 173 return res; 174 175 root_swap = res; 176 res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR); 177 if (res) 178 return res; 179 180 res = set_blocksize(resume_bdev, PAGE_SIZE); 181 if (res < 0) 182 blkdev_put(resume_bdev); 183 184 return res; 185 } 186 187 /** 188 * write_page - Write one page to given swap location. 189 * @buf: Address we're writing. 190 * @offset: Offset of the swap page we're writing to. 191 * @bio_chain: Link the next write BIO here 192 */ 193 194 static int write_page(void *buf, sector_t offset, struct bio **bio_chain) 195 { 196 void *src; 197 198 if (!offset) 199 return -ENOSPC; 200 201 if (bio_chain) { 202 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH); 203 if (src) { 204 memcpy(src, buf, PAGE_SIZE); 205 } else { 206 WARN_ON_ONCE(1); 207 bio_chain = NULL; /* Go synchronous */ 208 src = buf; 209 } 210 } else { 211 src = buf; 212 } 213 return bio_write_page(offset, src, bio_chain); 214 } 215 216 /* 217 * The swap map is a data structure used for keeping track of each page 218 * written to a swap partition. It consists of many swap_map_page 219 * structures that contain each an array of MAP_PAGE_SIZE swap entries. 220 * These structures are stored on the swap and linked together with the 221 * help of the .next_swap member. 222 * 223 * The swap map is created during suspend. The swap map pages are 224 * allocated and populated one at a time, so we only need one memory 225 * page to set up the entire structure. 226 * 227 * During resume we also only need to use one swap_map_page structure 228 * at a time. 229 */ 230 231 #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1) 232 233 struct swap_map_page { 234 sector_t entries[MAP_PAGE_ENTRIES]; 235 sector_t next_swap; 236 }; 237 238 /** 239 * The swap_map_handle structure is used for handling swap in 240 * a file-alike way 241 */ 242 243 struct swap_map_handle { 244 struct swap_map_page *cur; 245 sector_t cur_swap; 246 unsigned int k; 247 }; 248 249 static void release_swap_writer(struct swap_map_handle *handle) 250 { 251 if (handle->cur) 252 free_page((unsigned long)handle->cur); 253 handle->cur = NULL; 254 } 255 256 static int get_swap_writer(struct swap_map_handle *handle) 257 { 258 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); 259 if (!handle->cur) 260 return -ENOMEM; 261 handle->cur_swap = alloc_swapdev_block(root_swap); 262 if (!handle->cur_swap) { 263 release_swap_writer(handle); 264 return -ENOSPC; 265 } 266 handle->k = 0; 267 return 0; 268 } 269 270 static int swap_write_page(struct swap_map_handle *handle, void *buf, 271 struct bio **bio_chain) 272 { 273 int error = 0; 274 sector_t offset; 275 276 if (!handle->cur) 277 return -EINVAL; 278 offset = alloc_swapdev_block(root_swap); 279 error = write_page(buf, offset, bio_chain); 280 if (error) 281 return error; 282 handle->cur->entries[handle->k++] = offset; 283 if (handle->k >= MAP_PAGE_ENTRIES) { 284 error = wait_on_bio_chain(bio_chain); 285 if (error) 286 goto out; 287 offset = alloc_swapdev_block(root_swap); 288 if (!offset) 289 return -ENOSPC; 290 handle->cur->next_swap = offset; 291 error = write_page(handle->cur, handle->cur_swap, NULL); 292 if (error) 293 goto out; 294 memset(handle->cur, 0, PAGE_SIZE); 295 handle->cur_swap = offset; 296 handle->k = 0; 297 } 298 out: 299 return error; 300 } 301 302 static int flush_swap_writer(struct swap_map_handle *handle) 303 { 304 if (handle->cur && handle->cur_swap) 305 return write_page(handle->cur, handle->cur_swap, NULL); 306 else 307 return -EINVAL; 308 } 309 310 /** 311 * save_image - save the suspend image data 312 */ 313 314 static int save_image(struct swap_map_handle *handle, 315 struct snapshot_handle *snapshot, 316 unsigned int nr_to_write) 317 { 318 unsigned int m; 319 int ret; 320 int error = 0; 321 int nr_pages; 322 int err2; 323 struct bio *bio; 324 struct timeval start; 325 struct timeval stop; 326 327 printk("Saving image data pages (%u pages) ... ", nr_to_write); 328 m = nr_to_write / 100; 329 if (!m) 330 m = 1; 331 nr_pages = 0; 332 bio = NULL; 333 do_gettimeofday(&start); 334 do { 335 ret = snapshot_read_next(snapshot, PAGE_SIZE); 336 if (ret > 0) { 337 error = swap_write_page(handle, data_of(*snapshot), 338 &bio); 339 if (error) 340 break; 341 if (!(nr_pages % m)) 342 printk("\b\b\b\b%3d%%", nr_pages / m); 343 nr_pages++; 344 } 345 } while (ret > 0); 346 err2 = wait_on_bio_chain(&bio); 347 do_gettimeofday(&stop); 348 if (!error) 349 error = err2; 350 if (!error) 351 printk("\b\b\b\bdone\n"); 352 swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); 353 return error; 354 } 355 356 /** 357 * enough_swap - Make sure we have enough swap to save the image. 358 * 359 * Returns TRUE or FALSE after checking the total amount of swap 360 * space avaiable from the resume partition. 361 */ 362 363 static int enough_swap(unsigned int nr_pages) 364 { 365 unsigned int free_swap = count_swap_pages(root_swap, 1); 366 367 pr_debug("swsusp: free swap pages: %u\n", free_swap); 368 return free_swap > nr_pages + PAGES_FOR_IO; 369 } 370 371 /** 372 * swsusp_write - Write entire image and metadata. 373 * 374 * It is important _NOT_ to umount filesystems at this point. We want 375 * them synced (in case something goes wrong) but we DO not want to mark 376 * filesystem clean: it is not. (And it does not matter, if we resume 377 * correctly, we'll mark system clean, anyway.) 378 */ 379 380 int swsusp_write(void) 381 { 382 struct swap_map_handle handle; 383 struct snapshot_handle snapshot; 384 struct swsusp_info *header; 385 int error; 386 387 error = swsusp_swap_check(); 388 if (error) { 389 printk(KERN_ERR "swsusp: Cannot find swap device, try " 390 "swapon -a.\n"); 391 return error; 392 } 393 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 394 error = snapshot_read_next(&snapshot, PAGE_SIZE); 395 if (error < PAGE_SIZE) { 396 if (error >= 0) 397 error = -EFAULT; 398 399 goto out; 400 } 401 header = (struct swsusp_info *)data_of(snapshot); 402 if (!enough_swap(header->pages)) { 403 printk(KERN_ERR "swsusp: Not enough free swap\n"); 404 error = -ENOSPC; 405 goto out; 406 } 407 error = get_swap_writer(&handle); 408 if (!error) { 409 sector_t start = handle.cur_swap; 410 411 error = swap_write_page(&handle, header, NULL); 412 if (!error) 413 error = save_image(&handle, &snapshot, 414 header->pages - 1); 415 416 if (!error) { 417 flush_swap_writer(&handle); 418 printk("S"); 419 error = mark_swapfiles(start); 420 printk("|\n"); 421 } 422 } 423 if (error) 424 free_all_swap_pages(root_swap); 425 426 release_swap_writer(&handle); 427 out: 428 swsusp_close(); 429 return error; 430 } 431 432 /** 433 * The following functions allow us to read data using a swap map 434 * in a file-alike way 435 */ 436 437 static void release_swap_reader(struct swap_map_handle *handle) 438 { 439 if (handle->cur) 440 free_page((unsigned long)handle->cur); 441 handle->cur = NULL; 442 } 443 444 static int get_swap_reader(struct swap_map_handle *handle, sector_t start) 445 { 446 int error; 447 448 if (!start) 449 return -EINVAL; 450 451 handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH); 452 if (!handle->cur) 453 return -ENOMEM; 454 455 error = bio_read_page(start, handle->cur, NULL); 456 if (error) { 457 release_swap_reader(handle); 458 return error; 459 } 460 handle->k = 0; 461 return 0; 462 } 463 464 static int swap_read_page(struct swap_map_handle *handle, void *buf, 465 struct bio **bio_chain) 466 { 467 sector_t offset; 468 int error; 469 470 if (!handle->cur) 471 return -EINVAL; 472 offset = handle->cur->entries[handle->k]; 473 if (!offset) 474 return -EFAULT; 475 error = bio_read_page(offset, buf, bio_chain); 476 if (error) 477 return error; 478 if (++handle->k >= MAP_PAGE_ENTRIES) { 479 error = wait_on_bio_chain(bio_chain); 480 handle->k = 0; 481 offset = handle->cur->next_swap; 482 if (!offset) 483 release_swap_reader(handle); 484 else if (!error) 485 error = bio_read_page(offset, handle->cur, NULL); 486 } 487 return error; 488 } 489 490 /** 491 * load_image - load the image using the swap map handle 492 * @handle and the snapshot handle @snapshot 493 * (assume there are @nr_pages pages to load) 494 */ 495 496 static int load_image(struct swap_map_handle *handle, 497 struct snapshot_handle *snapshot, 498 unsigned int nr_to_read) 499 { 500 unsigned int m; 501 int error = 0; 502 struct timeval start; 503 struct timeval stop; 504 struct bio *bio; 505 int err2; 506 unsigned nr_pages; 507 508 printk("Loading image data pages (%u pages) ... ", nr_to_read); 509 m = nr_to_read / 100; 510 if (!m) 511 m = 1; 512 nr_pages = 0; 513 bio = NULL; 514 do_gettimeofday(&start); 515 for ( ; ; ) { 516 error = snapshot_write_next(snapshot, PAGE_SIZE); 517 if (error <= 0) 518 break; 519 error = swap_read_page(handle, data_of(*snapshot), &bio); 520 if (error) 521 break; 522 if (snapshot->sync_read) 523 error = wait_on_bio_chain(&bio); 524 if (error) 525 break; 526 if (!(nr_pages % m)) 527 printk("\b\b\b\b%3d%%", nr_pages / m); 528 nr_pages++; 529 } 530 err2 = wait_on_bio_chain(&bio); 531 do_gettimeofday(&stop); 532 if (!error) 533 error = err2; 534 if (!error) { 535 printk("\b\b\b\bdone\n"); 536 snapshot_write_finalize(snapshot); 537 if (!snapshot_image_loaded(snapshot)) 538 error = -ENODATA; 539 } 540 swsusp_show_speed(&start, &stop, nr_to_read, "Read"); 541 return error; 542 } 543 544 int swsusp_read(void) 545 { 546 int error; 547 struct swap_map_handle handle; 548 struct snapshot_handle snapshot; 549 struct swsusp_info *header; 550 551 if (IS_ERR(resume_bdev)) { 552 pr_debug("swsusp: block device not initialised\n"); 553 return PTR_ERR(resume_bdev); 554 } 555 556 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 557 error = snapshot_write_next(&snapshot, PAGE_SIZE); 558 if (error < PAGE_SIZE) 559 return error < 0 ? error : -EFAULT; 560 header = (struct swsusp_info *)data_of(snapshot); 561 error = get_swap_reader(&handle, swsusp_header->image); 562 if (!error) 563 error = swap_read_page(&handle, header, NULL); 564 if (!error) 565 error = load_image(&handle, &snapshot, header->pages - 1); 566 release_swap_reader(&handle); 567 568 blkdev_put(resume_bdev); 569 570 if (!error) 571 pr_debug("swsusp: Reading resume file was successful\n"); 572 else 573 pr_debug("swsusp: Error %d resuming\n", error); 574 return error; 575 } 576 577 /** 578 * swsusp_check - Check for swsusp signature in the resume device 579 */ 580 581 int swsusp_check(void) 582 { 583 int error; 584 585 resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); 586 if (!IS_ERR(resume_bdev)) { 587 set_blocksize(resume_bdev, PAGE_SIZE); 588 memset(swsusp_header, 0, sizeof(PAGE_SIZE)); 589 error = bio_read_page(swsusp_resume_block, 590 swsusp_header, NULL); 591 if (error) 592 return error; 593 594 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) { 595 memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); 596 /* Reset swap signature now */ 597 error = bio_write_page(swsusp_resume_block, 598 swsusp_header, NULL); 599 } else { 600 return -EINVAL; 601 } 602 if (error) 603 blkdev_put(resume_bdev); 604 else 605 pr_debug("swsusp: Signature found, resuming\n"); 606 } else { 607 error = PTR_ERR(resume_bdev); 608 } 609 610 if (error) 611 pr_debug("swsusp: Error %d check for resume file\n", error); 612 613 return error; 614 } 615 616 /** 617 * swsusp_close - close swap device. 618 */ 619 620 void swsusp_close(void) 621 { 622 if (IS_ERR(resume_bdev)) { 623 pr_debug("swsusp: block device not initialised\n"); 624 return; 625 } 626 627 blkdev_put(resume_bdev); 628 } 629 630 static int swsusp_header_init(void) 631 { 632 swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL); 633 if (!swsusp_header) 634 panic("Could not allocate memory for swsusp_header\n"); 635 return 0; 636 } 637 638 core_initcall(swsusp_header_init); 639