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/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 27 #include "power.h" 28 29 #define SWSUSP_SIG "S1SUSPEND" 30 31 struct swsusp_header { 32 char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)]; 33 sector_t image; 34 unsigned int flags; /* Flags to pass to the "boot" kernel */ 35 char orig_sig[10]; 36 char sig[10]; 37 } __attribute__((packed)); 38 39 static struct swsusp_header *swsusp_header; 40 41 /* 42 * General things 43 */ 44 45 static unsigned short root_swap = 0xffff; 46 static struct block_device *resume_bdev; 47 48 /** 49 * submit - submit BIO request. 50 * @rw: READ or WRITE. 51 * @off physical offset of page. 52 * @page: page we're reading or writing. 53 * @bio_chain: list of pending biod (for async reading) 54 * 55 * Straight from the textbook - allocate and initialize the bio. 56 * If we're reading, make sure the page is marked as dirty. 57 * Then submit it and, if @bio_chain == NULL, wait. 58 */ 59 static int submit(int rw, pgoff_t page_off, struct page *page, 60 struct bio **bio_chain) 61 { 62 const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG); 63 struct bio *bio; 64 65 bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1); 66 bio->bi_sector = page_off * (PAGE_SIZE >> 9); 67 bio->bi_bdev = resume_bdev; 68 bio->bi_end_io = end_swap_bio_read; 69 70 if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { 71 printk(KERN_ERR "PM: Adding page to bio failed at %ld\n", 72 page_off); 73 bio_put(bio); 74 return -EFAULT; 75 } 76 77 lock_page(page); 78 bio_get(bio); 79 80 if (bio_chain == NULL) { 81 submit_bio(bio_rw, bio); 82 wait_on_page_locked(page); 83 if (rw == READ) 84 bio_set_pages_dirty(bio); 85 bio_put(bio); 86 } else { 87 if (rw == READ) 88 get_page(page); /* These pages are freed later */ 89 bio->bi_private = *bio_chain; 90 *bio_chain = bio; 91 submit_bio(bio_rw, bio); 92 } 93 return 0; 94 } 95 96 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain) 97 { 98 return submit(READ, page_off, virt_to_page(addr), bio_chain); 99 } 100 101 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain) 102 { 103 return submit(WRITE, page_off, virt_to_page(addr), bio_chain); 104 } 105 106 static int wait_on_bio_chain(struct bio **bio_chain) 107 { 108 struct bio *bio; 109 struct bio *next_bio; 110 int ret = 0; 111 112 if (bio_chain == NULL) 113 return 0; 114 115 bio = *bio_chain; 116 if (bio == NULL) 117 return 0; 118 while (bio) { 119 struct page *page; 120 121 next_bio = bio->bi_private; 122 page = bio->bi_io_vec[0].bv_page; 123 wait_on_page_locked(page); 124 if (!PageUptodate(page) || PageError(page)) 125 ret = -EIO; 126 put_page(page); 127 bio_put(bio); 128 bio = next_bio; 129 } 130 *bio_chain = NULL; 131 return ret; 132 } 133 134 /* 135 * Saving part 136 */ 137 138 static int mark_swapfiles(sector_t start, unsigned int flags) 139 { 140 int error; 141 142 bio_read_page(swsusp_resume_block, swsusp_header, NULL); 143 if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) || 144 !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) { 145 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10); 146 memcpy(swsusp_header->sig,SWSUSP_SIG, 10); 147 swsusp_header->image = start; 148 swsusp_header->flags = flags; 149 error = bio_write_page(swsusp_resume_block, 150 swsusp_header, NULL); 151 } else { 152 printk(KERN_ERR "PM: Swap header not found!\n"); 153 error = -ENODEV; 154 } 155 return error; 156 } 157 158 /** 159 * swsusp_swap_check - check if the resume device is a swap device 160 * and get its index (if so) 161 */ 162 163 static int swsusp_swap_check(void) /* This is called before saving image */ 164 { 165 int res; 166 167 res = swap_type_of(swsusp_resume_device, swsusp_resume_block, 168 &resume_bdev); 169 if (res < 0) 170 return res; 171 172 root_swap = res; 173 res = blkdev_get(resume_bdev, FMODE_WRITE); 174 if (res) 175 return res; 176 177 res = set_blocksize(resume_bdev, PAGE_SIZE); 178 if (res < 0) 179 blkdev_put(resume_bdev, FMODE_WRITE); 180 181 return res; 182 } 183 184 /** 185 * write_page - Write one page to given swap location. 186 * @buf: Address we're writing. 187 * @offset: Offset of the swap page we're writing to. 188 * @bio_chain: Link the next write BIO here 189 */ 190 191 static int write_page(void *buf, sector_t offset, struct bio **bio_chain) 192 { 193 void *src; 194 195 if (!offset) 196 return -ENOSPC; 197 198 if (bio_chain) { 199 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH); 200 if (src) { 201 memcpy(src, buf, PAGE_SIZE); 202 } else { 203 WARN_ON_ONCE(1); 204 bio_chain = NULL; /* Go synchronous */ 205 src = buf; 206 } 207 } else { 208 src = buf; 209 } 210 return bio_write_page(offset, src, bio_chain); 211 } 212 213 /* 214 * The swap map is a data structure used for keeping track of each page 215 * written to a swap partition. It consists of many swap_map_page 216 * structures that contain each an array of MAP_PAGE_SIZE swap entries. 217 * These structures are stored on the swap and linked together with the 218 * help of the .next_swap member. 219 * 220 * The swap map is created during suspend. The swap map pages are 221 * allocated and populated one at a time, so we only need one memory 222 * page to set up the entire structure. 223 * 224 * During resume we also only need to use one swap_map_page structure 225 * at a time. 226 */ 227 228 #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1) 229 230 struct swap_map_page { 231 sector_t entries[MAP_PAGE_ENTRIES]; 232 sector_t next_swap; 233 }; 234 235 /** 236 * The swap_map_handle structure is used for handling swap in 237 * a file-alike way 238 */ 239 240 struct swap_map_handle { 241 struct swap_map_page *cur; 242 sector_t cur_swap; 243 unsigned int k; 244 }; 245 246 static void release_swap_writer(struct swap_map_handle *handle) 247 { 248 if (handle->cur) 249 free_page((unsigned long)handle->cur); 250 handle->cur = NULL; 251 } 252 253 static int get_swap_writer(struct swap_map_handle *handle) 254 { 255 handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); 256 if (!handle->cur) 257 return -ENOMEM; 258 handle->cur_swap = alloc_swapdev_block(root_swap); 259 if (!handle->cur_swap) { 260 release_swap_writer(handle); 261 return -ENOSPC; 262 } 263 handle->k = 0; 264 return 0; 265 } 266 267 static int swap_write_page(struct swap_map_handle *handle, void *buf, 268 struct bio **bio_chain) 269 { 270 int error = 0; 271 sector_t offset; 272 273 if (!handle->cur) 274 return -EINVAL; 275 offset = alloc_swapdev_block(root_swap); 276 error = write_page(buf, offset, bio_chain); 277 if (error) 278 return error; 279 handle->cur->entries[handle->k++] = offset; 280 if (handle->k >= MAP_PAGE_ENTRIES) { 281 error = wait_on_bio_chain(bio_chain); 282 if (error) 283 goto out; 284 offset = alloc_swapdev_block(root_swap); 285 if (!offset) 286 return -ENOSPC; 287 handle->cur->next_swap = offset; 288 error = write_page(handle->cur, handle->cur_swap, NULL); 289 if (error) 290 goto out; 291 memset(handle->cur, 0, PAGE_SIZE); 292 handle->cur_swap = offset; 293 handle->k = 0; 294 } 295 out: 296 return error; 297 } 298 299 static int flush_swap_writer(struct swap_map_handle *handle) 300 { 301 if (handle->cur && handle->cur_swap) 302 return write_page(handle->cur, handle->cur_swap, NULL); 303 else 304 return -EINVAL; 305 } 306 307 /** 308 * save_image - save the suspend image data 309 */ 310 311 static int save_image(struct swap_map_handle *handle, 312 struct snapshot_handle *snapshot, 313 unsigned int nr_to_write) 314 { 315 unsigned int m; 316 int ret; 317 int error = 0; 318 int nr_pages; 319 int err2; 320 struct bio *bio; 321 struct timeval start; 322 struct timeval stop; 323 324 printk(KERN_INFO "PM: Saving image data pages (%u pages) ... ", 325 nr_to_write); 326 m = nr_to_write / 100; 327 if (!m) 328 m = 1; 329 nr_pages = 0; 330 bio = NULL; 331 do_gettimeofday(&start); 332 do { 333 ret = snapshot_read_next(snapshot, PAGE_SIZE); 334 if (ret > 0) { 335 error = swap_write_page(handle, data_of(*snapshot), 336 &bio); 337 if (error) 338 break; 339 if (!(nr_pages % m)) 340 printk("\b\b\b\b%3d%%", nr_pages / m); 341 nr_pages++; 342 } 343 } while (ret > 0); 344 err2 = wait_on_bio_chain(&bio); 345 do_gettimeofday(&stop); 346 if (!error) 347 error = err2; 348 if (!error) 349 printk("\b\b\b\bdone\n"); 350 swsusp_show_speed(&start, &stop, nr_to_write, "Wrote"); 351 return error; 352 } 353 354 /** 355 * enough_swap - Make sure we have enough swap to save the image. 356 * 357 * Returns TRUE or FALSE after checking the total amount of swap 358 * space avaiable from the resume partition. 359 */ 360 361 static int enough_swap(unsigned int nr_pages) 362 { 363 unsigned int free_swap = count_swap_pages(root_swap, 1); 364 365 pr_debug("PM: Free swap pages: %u\n", free_swap); 366 return free_swap > nr_pages + PAGES_FOR_IO; 367 } 368 369 /** 370 * swsusp_write - Write entire image and metadata. 371 * @flags: flags to pass to the "boot" kernel in the image header 372 * 373 * It is important _NOT_ to umount filesystems at this point. We want 374 * them synced (in case something goes wrong) but we DO not want to mark 375 * filesystem clean: it is not. (And it does not matter, if we resume 376 * correctly, we'll mark system clean, anyway.) 377 */ 378 379 int swsusp_write(unsigned int flags) 380 { 381 struct swap_map_handle handle; 382 struct snapshot_handle snapshot; 383 struct swsusp_info *header; 384 int error; 385 386 error = swsusp_swap_check(); 387 if (error) { 388 printk(KERN_ERR "PM: Cannot find swap device, try " 389 "swapon -a.\n"); 390 return error; 391 } 392 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 393 error = snapshot_read_next(&snapshot, PAGE_SIZE); 394 if (error < PAGE_SIZE) { 395 if (error >= 0) 396 error = -EFAULT; 397 398 goto out; 399 } 400 header = (struct swsusp_info *)data_of(snapshot); 401 if (!enough_swap(header->pages)) { 402 printk(KERN_ERR "PM: Not enough free swap\n"); 403 error = -ENOSPC; 404 goto out; 405 } 406 error = get_swap_writer(&handle); 407 if (!error) { 408 sector_t start = handle.cur_swap; 409 410 error = swap_write_page(&handle, header, NULL); 411 if (!error) 412 error = save_image(&handle, &snapshot, 413 header->pages - 1); 414 415 if (!error) { 416 flush_swap_writer(&handle); 417 printk(KERN_INFO "PM: S"); 418 error = mark_swapfiles(start, flags); 419 printk("|\n"); 420 } 421 } 422 if (error) 423 free_all_swap_pages(root_swap); 424 425 release_swap_writer(&handle); 426 out: 427 swsusp_close(FMODE_WRITE); 428 return error; 429 } 430 431 /** 432 * The following functions allow us to read data using a swap map 433 * in a file-alike way 434 */ 435 436 static void release_swap_reader(struct swap_map_handle *handle) 437 { 438 if (handle->cur) 439 free_page((unsigned long)handle->cur); 440 handle->cur = NULL; 441 } 442 443 static int get_swap_reader(struct swap_map_handle *handle, sector_t start) 444 { 445 int error; 446 447 if (!start) 448 return -EINVAL; 449 450 handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH); 451 if (!handle->cur) 452 return -ENOMEM; 453 454 error = bio_read_page(start, handle->cur, NULL); 455 if (error) { 456 release_swap_reader(handle); 457 return error; 458 } 459 handle->k = 0; 460 return 0; 461 } 462 463 static int swap_read_page(struct swap_map_handle *handle, void *buf, 464 struct bio **bio_chain) 465 { 466 sector_t offset; 467 int error; 468 469 if (!handle->cur) 470 return -EINVAL; 471 offset = handle->cur->entries[handle->k]; 472 if (!offset) 473 return -EFAULT; 474 error = bio_read_page(offset, buf, bio_chain); 475 if (error) 476 return error; 477 if (++handle->k >= MAP_PAGE_ENTRIES) { 478 error = wait_on_bio_chain(bio_chain); 479 handle->k = 0; 480 offset = handle->cur->next_swap; 481 if (!offset) 482 release_swap_reader(handle); 483 else if (!error) 484 error = bio_read_page(offset, handle->cur, NULL); 485 } 486 return error; 487 } 488 489 /** 490 * load_image - load the image using the swap map handle 491 * @handle and the snapshot handle @snapshot 492 * (assume there are @nr_pages pages to load) 493 */ 494 495 static int load_image(struct swap_map_handle *handle, 496 struct snapshot_handle *snapshot, 497 unsigned int nr_to_read) 498 { 499 unsigned int m; 500 int error = 0; 501 struct timeval start; 502 struct timeval stop; 503 struct bio *bio; 504 int err2; 505 unsigned nr_pages; 506 507 printk(KERN_INFO "PM: Loading image data pages (%u pages) ... ", 508 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 /** 545 * swsusp_read - read the hibernation image. 546 * @flags_p: flags passed by the "frozen" kernel in the image header should 547 * be written into this memeory location 548 */ 549 550 int swsusp_read(unsigned int *flags_p) 551 { 552 int error; 553 struct swap_map_handle handle; 554 struct snapshot_handle snapshot; 555 struct swsusp_info *header; 556 557 *flags_p = swsusp_header->flags; 558 if (IS_ERR(resume_bdev)) { 559 pr_debug("PM: Image device not initialised\n"); 560 return PTR_ERR(resume_bdev); 561 } 562 563 memset(&snapshot, 0, sizeof(struct snapshot_handle)); 564 error = snapshot_write_next(&snapshot, PAGE_SIZE); 565 if (error < PAGE_SIZE) 566 return error < 0 ? error : -EFAULT; 567 header = (struct swsusp_info *)data_of(snapshot); 568 error = get_swap_reader(&handle, swsusp_header->image); 569 if (!error) 570 error = swap_read_page(&handle, header, NULL); 571 if (!error) 572 error = load_image(&handle, &snapshot, header->pages - 1); 573 release_swap_reader(&handle); 574 575 blkdev_put(resume_bdev, FMODE_READ); 576 577 if (!error) 578 pr_debug("PM: Image successfully loaded\n"); 579 else 580 pr_debug("PM: Error %d resuming\n", error); 581 return error; 582 } 583 584 /** 585 * swsusp_check - Check for swsusp signature in the resume device 586 */ 587 588 int swsusp_check(void) 589 { 590 int error; 591 592 resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); 593 if (!IS_ERR(resume_bdev)) { 594 set_blocksize(resume_bdev, PAGE_SIZE); 595 memset(swsusp_header, 0, PAGE_SIZE); 596 error = bio_read_page(swsusp_resume_block, 597 swsusp_header, NULL); 598 if (error) 599 return error; 600 601 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) { 602 memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10); 603 /* Reset swap signature now */ 604 error = bio_write_page(swsusp_resume_block, 605 swsusp_header, NULL); 606 } else { 607 return -EINVAL; 608 } 609 if (error) 610 blkdev_put(resume_bdev, FMODE_READ); 611 else 612 pr_debug("PM: Signature found, resuming\n"); 613 } else { 614 error = PTR_ERR(resume_bdev); 615 } 616 617 if (error) 618 pr_debug("PM: Error %d checking image file\n", error); 619 620 return error; 621 } 622 623 /** 624 * swsusp_close - close swap device. 625 */ 626 627 void swsusp_close(fmode_t mode) 628 { 629 if (IS_ERR(resume_bdev)) { 630 pr_debug("PM: Image device not initialised\n"); 631 return; 632 } 633 634 blkdev_put(resume_bdev, mode); 635 } 636 637 static int swsusp_header_init(void) 638 { 639 swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL); 640 if (!swsusp_header) 641 panic("Could not allocate memory for swsusp_header\n"); 642 return 0; 643 } 644 645 core_initcall(swsusp_header_init); 646