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Commit | Line | Data |
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61159a31 RW |
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> | |
546e0d27 | 25 | #include <linux/blkdev.h> |
61159a31 RW |
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(swp_entry_t)]; | |
38 | swp_entry_t image; | |
39 | char orig_sig[10]; | |
40 | char sig[10]; | |
41 | } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header; | |
42 | ||
43 | /* | |
3fc6b34f | 44 | * General things |
61159a31 RW |
45 | */ |
46 | ||
47 | static unsigned short root_swap = 0xffff; | |
3fc6b34f RW |
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) | |
104 | { | |
105 | return submit(WRITE, page_off, virt_to_page(addr), NULL); | |
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 | */ | |
61159a31 RW |
159 | |
160 | static int mark_swapfiles(swp_entry_t start) | |
161 | { | |
162 | int error; | |
163 | ||
ab954160 AM |
164 | rw_swap_page_sync(READ, swp_entry(root_swap, 0), |
165 | virt_to_page((unsigned long)&swsusp_header), NULL); | |
61159a31 RW |
166 | if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) || |
167 | !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) { | |
168 | memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10); | |
169 | memcpy(swsusp_header.sig,SWSUSP_SIG, 10); | |
170 | swsusp_header.image = start; | |
ab954160 AM |
171 | error = rw_swap_page_sync(WRITE, swp_entry(root_swap, 0), |
172 | virt_to_page((unsigned long)&swsusp_header), | |
173 | NULL); | |
61159a31 RW |
174 | } else { |
175 | pr_debug("swsusp: Partition is not swap space.\n"); | |
176 | error = -ENODEV; | |
177 | } | |
178 | return error; | |
179 | } | |
180 | ||
181 | /** | |
182 | * swsusp_swap_check - check if the resume device is a swap device | |
183 | * and get its index (if so) | |
184 | */ | |
185 | ||
186 | static int swsusp_swap_check(void) /* This is called before saving image */ | |
187 | { | |
915bae9e | 188 | int res = swap_type_of(swsusp_resume_device, 0); |
61159a31 RW |
189 | |
190 | if (res >= 0) { | |
191 | root_swap = res; | |
192 | return 0; | |
193 | } | |
194 | return res; | |
195 | } | |
196 | ||
197 | /** | |
198 | * write_page - Write one page to given swap location. | |
199 | * @buf: Address we're writing. | |
200 | * @offset: Offset of the swap page we're writing to. | |
ab954160 | 201 | * @bio_chain: Link the next write BIO here |
61159a31 RW |
202 | */ |
203 | ||
ab954160 | 204 | static int write_page(void *buf, unsigned long offset, struct bio **bio_chain) |
61159a31 RW |
205 | { |
206 | swp_entry_t entry; | |
207 | int error = -ENOSPC; | |
208 | ||
209 | if (offset) { | |
ab954160 AM |
210 | struct page *page = virt_to_page(buf); |
211 | ||
212 | if (bio_chain) { | |
213 | /* | |
214 | * Whether or not we successfully allocated a copy page, | |
215 | * we take a ref on the page here. It gets undone in | |
216 | * wait_on_bio_chain(). | |
217 | */ | |
218 | struct page *page_copy; | |
219 | page_copy = alloc_page(GFP_ATOMIC); | |
220 | if (page_copy == NULL) { | |
221 | WARN_ON_ONCE(1); | |
222 | bio_chain = NULL; /* Go synchronous */ | |
223 | get_page(page); | |
224 | } else { | |
225 | memcpy(page_address(page_copy), | |
226 | page_address(page), PAGE_SIZE); | |
227 | page = page_copy; | |
228 | } | |
229 | } | |
61159a31 | 230 | entry = swp_entry(root_swap, offset); |
ab954160 | 231 | error = rw_swap_page_sync(WRITE, entry, page, bio_chain); |
61159a31 RW |
232 | } |
233 | return error; | |
234 | } | |
235 | ||
236 | /* | |
237 | * The swap map is a data structure used for keeping track of each page | |
238 | * written to a swap partition. It consists of many swap_map_page | |
239 | * structures that contain each an array of MAP_PAGE_SIZE swap entries. | |
240 | * These structures are stored on the swap and linked together with the | |
241 | * help of the .next_swap member. | |
242 | * | |
243 | * The swap map is created during suspend. The swap map pages are | |
244 | * allocated and populated one at a time, so we only need one memory | |
245 | * page to set up the entire structure. | |
246 | * | |
247 | * During resume we also only need to use one swap_map_page structure | |
248 | * at a time. | |
249 | */ | |
250 | ||
251 | #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1) | |
252 | ||
253 | struct swap_map_page { | |
254 | unsigned long entries[MAP_PAGE_ENTRIES]; | |
255 | unsigned long next_swap; | |
256 | }; | |
257 | ||
258 | /** | |
259 | * The swap_map_handle structure is used for handling swap in | |
260 | * a file-alike way | |
261 | */ | |
262 | ||
263 | struct swap_map_handle { | |
264 | struct swap_map_page *cur; | |
265 | unsigned long cur_swap; | |
266 | struct bitmap_page *bitmap; | |
267 | unsigned int k; | |
268 | }; | |
269 | ||
270 | static void release_swap_writer(struct swap_map_handle *handle) | |
271 | { | |
272 | if (handle->cur) | |
273 | free_page((unsigned long)handle->cur); | |
274 | handle->cur = NULL; | |
275 | if (handle->bitmap) | |
276 | free_bitmap(handle->bitmap); | |
277 | handle->bitmap = NULL; | |
278 | } | |
279 | ||
280 | static int get_swap_writer(struct swap_map_handle *handle) | |
281 | { | |
282 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); | |
283 | if (!handle->cur) | |
284 | return -ENOMEM; | |
285 | handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0)); | |
286 | if (!handle->bitmap) { | |
287 | release_swap_writer(handle); | |
288 | return -ENOMEM; | |
289 | } | |
290 | handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap); | |
291 | if (!handle->cur_swap) { | |
292 | release_swap_writer(handle); | |
293 | return -ENOSPC; | |
294 | } | |
295 | handle->k = 0; | |
296 | return 0; | |
297 | } | |
298 | ||
ab954160 AM |
299 | static int swap_write_page(struct swap_map_handle *handle, void *buf, |
300 | struct bio **bio_chain) | |
301 | { | |
302 | int error = 0; | |
61159a31 RW |
303 | unsigned long offset; |
304 | ||
305 | if (!handle->cur) | |
306 | return -EINVAL; | |
307 | offset = alloc_swap_page(root_swap, handle->bitmap); | |
ab954160 | 308 | error = write_page(buf, offset, bio_chain); |
61159a31 RW |
309 | if (error) |
310 | return error; | |
311 | handle->cur->entries[handle->k++] = offset; | |
312 | if (handle->k >= MAP_PAGE_ENTRIES) { | |
ab954160 AM |
313 | error = wait_on_bio_chain(bio_chain); |
314 | if (error) | |
315 | goto out; | |
61159a31 RW |
316 | offset = alloc_swap_page(root_swap, handle->bitmap); |
317 | if (!offset) | |
318 | return -ENOSPC; | |
319 | handle->cur->next_swap = offset; | |
ab954160 | 320 | error = write_page(handle->cur, handle->cur_swap, NULL); |
61159a31 | 321 | if (error) |
ab954160 | 322 | goto out; |
61159a31 RW |
323 | memset(handle->cur, 0, PAGE_SIZE); |
324 | handle->cur_swap = offset; | |
325 | handle->k = 0; | |
326 | } | |
ab954160 AM |
327 | out: |
328 | return error; | |
61159a31 RW |
329 | } |
330 | ||
331 | static int flush_swap_writer(struct swap_map_handle *handle) | |
332 | { | |
333 | if (handle->cur && handle->cur_swap) | |
ab954160 | 334 | return write_page(handle->cur, handle->cur_swap, NULL); |
61159a31 RW |
335 | else |
336 | return -EINVAL; | |
337 | } | |
338 | ||
339 | /** | |
340 | * save_image - save the suspend image data | |
341 | */ | |
342 | ||
343 | static int save_image(struct swap_map_handle *handle, | |
344 | struct snapshot_handle *snapshot, | |
3a4f7577 | 345 | unsigned int nr_to_write) |
61159a31 RW |
346 | { |
347 | unsigned int m; | |
348 | int ret; | |
349 | int error = 0; | |
3a4f7577 | 350 | int nr_pages; |
ab954160 AM |
351 | int err2; |
352 | struct bio *bio; | |
3a4f7577 AM |
353 | struct timeval start; |
354 | struct timeval stop; | |
61159a31 | 355 | |
3a4f7577 AM |
356 | printk("Saving image data pages (%u pages) ... ", nr_to_write); |
357 | m = nr_to_write / 100; | |
61159a31 RW |
358 | if (!m) |
359 | m = 1; | |
360 | nr_pages = 0; | |
ab954160 | 361 | bio = NULL; |
3a4f7577 | 362 | do_gettimeofday(&start); |
61159a31 RW |
363 | do { |
364 | ret = snapshot_read_next(snapshot, PAGE_SIZE); | |
365 | if (ret > 0) { | |
ab954160 AM |
366 | error = swap_write_page(handle, data_of(*snapshot), |
367 | &bio); | |
61159a31 RW |
368 | if (error) |
369 | break; | |
370 | if (!(nr_pages % m)) | |
371 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
372 | nr_pages++; | |
373 | } | |
374 | } while (ret > 0); | |
ab954160 | 375 | err2 = wait_on_bio_chain(&bio); |
3a4f7577 | 376 | do_gettimeofday(&stop); |
ab954160 AM |
377 | if (!error) |
378 | error = err2; | |
61159a31 RW |
379 | if (!error) |
380 | printk("\b\b\b\bdone\n"); | |
3a4f7577 | 381 | show_speed(&start, &stop, nr_to_write, "Wrote"); |
61159a31 RW |
382 | return error; |
383 | } | |
384 | ||
385 | /** | |
386 | * enough_swap - Make sure we have enough swap to save the image. | |
387 | * | |
388 | * Returns TRUE or FALSE after checking the total amount of swap | |
389 | * space avaiable from the resume partition. | |
390 | */ | |
391 | ||
392 | static int enough_swap(unsigned int nr_pages) | |
393 | { | |
394 | unsigned int free_swap = count_swap_pages(root_swap, 1); | |
395 | ||
396 | pr_debug("swsusp: free swap pages: %u\n", free_swap); | |
940864dd | 397 | return free_swap > nr_pages + PAGES_FOR_IO; |
61159a31 RW |
398 | } |
399 | ||
400 | /** | |
401 | * swsusp_write - Write entire image and metadata. | |
402 | * | |
403 | * It is important _NOT_ to umount filesystems at this point. We want | |
404 | * them synced (in case something goes wrong) but we DO not want to mark | |
405 | * filesystem clean: it is not. (And it does not matter, if we resume | |
406 | * correctly, we'll mark system clean, anyway.) | |
407 | */ | |
408 | ||
409 | int swsusp_write(void) | |
410 | { | |
411 | struct swap_map_handle handle; | |
412 | struct snapshot_handle snapshot; | |
413 | struct swsusp_info *header; | |
61159a31 RW |
414 | int error; |
415 | ||
416 | if ((error = swsusp_swap_check())) { | |
546e0d27 AM |
417 | printk(KERN_ERR "swsusp: Cannot find swap device, try " |
418 | "swapon -a.\n"); | |
61159a31 RW |
419 | return error; |
420 | } | |
421 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
422 | error = snapshot_read_next(&snapshot, PAGE_SIZE); | |
423 | if (error < PAGE_SIZE) | |
424 | return error < 0 ? error : -EFAULT; | |
425 | header = (struct swsusp_info *)data_of(snapshot); | |
426 | if (!enough_swap(header->pages)) { | |
427 | printk(KERN_ERR "swsusp: Not enough free swap\n"); | |
428 | return -ENOSPC; | |
429 | } | |
430 | error = get_swap_writer(&handle); | |
431 | if (!error) { | |
712f403a | 432 | unsigned long start = handle.cur_swap; |
ab954160 | 433 | error = swap_write_page(&handle, header, NULL); |
712f403a AM |
434 | if (!error) |
435 | error = save_image(&handle, &snapshot, | |
436 | header->pages - 1); | |
437 | if (!error) { | |
438 | flush_swap_writer(&handle); | |
439 | printk("S"); | |
440 | error = mark_swapfiles(swp_entry(root_swap, start)); | |
441 | printk("|\n"); | |
442 | } | |
61159a31 RW |
443 | } |
444 | if (error) | |
445 | free_all_swap_pages(root_swap, handle.bitmap); | |
446 | release_swap_writer(&handle); | |
447 | return error; | |
448 | } | |
449 | ||
61159a31 RW |
450 | /** |
451 | * The following functions allow us to read data using a swap map | |
452 | * in a file-alike way | |
453 | */ | |
454 | ||
455 | static void release_swap_reader(struct swap_map_handle *handle) | |
456 | { | |
457 | if (handle->cur) | |
458 | free_page((unsigned long)handle->cur); | |
459 | handle->cur = NULL; | |
460 | } | |
461 | ||
462 | static int get_swap_reader(struct swap_map_handle *handle, | |
463 | swp_entry_t start) | |
464 | { | |
465 | int error; | |
466 | ||
467 | if (!swp_offset(start)) | |
468 | return -EINVAL; | |
469 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC); | |
470 | if (!handle->cur) | |
471 | return -ENOMEM; | |
546e0d27 | 472 | error = bio_read_page(swp_offset(start), handle->cur, NULL); |
61159a31 RW |
473 | if (error) { |
474 | release_swap_reader(handle); | |
475 | return error; | |
476 | } | |
477 | handle->k = 0; | |
478 | return 0; | |
479 | } | |
480 | ||
546e0d27 AM |
481 | static int swap_read_page(struct swap_map_handle *handle, void *buf, |
482 | struct bio **bio_chain) | |
61159a31 RW |
483 | { |
484 | unsigned long offset; | |
485 | int error; | |
486 | ||
487 | if (!handle->cur) | |
488 | return -EINVAL; | |
489 | offset = handle->cur->entries[handle->k]; | |
490 | if (!offset) | |
491 | return -EFAULT; | |
546e0d27 | 492 | error = bio_read_page(offset, buf, bio_chain); |
61159a31 RW |
493 | if (error) |
494 | return error; | |
495 | if (++handle->k >= MAP_PAGE_ENTRIES) { | |
546e0d27 | 496 | error = wait_on_bio_chain(bio_chain); |
61159a31 RW |
497 | handle->k = 0; |
498 | offset = handle->cur->next_swap; | |
499 | if (!offset) | |
500 | release_swap_reader(handle); | |
546e0d27 AM |
501 | else if (!error) |
502 | error = bio_read_page(offset, handle->cur, NULL); | |
61159a31 RW |
503 | } |
504 | return error; | |
505 | } | |
506 | ||
507 | /** | |
508 | * load_image - load the image using the swap map handle | |
509 | * @handle and the snapshot handle @snapshot | |
510 | * (assume there are @nr_pages pages to load) | |
511 | */ | |
512 | ||
513 | static int load_image(struct swap_map_handle *handle, | |
514 | struct snapshot_handle *snapshot, | |
546e0d27 | 515 | unsigned int nr_to_read) |
61159a31 RW |
516 | { |
517 | unsigned int m; | |
61159a31 | 518 | int error = 0; |
8c002494 AM |
519 | struct timeval start; |
520 | struct timeval stop; | |
546e0d27 AM |
521 | struct bio *bio; |
522 | int err2; | |
523 | unsigned nr_pages; | |
61159a31 | 524 | |
546e0d27 AM |
525 | printk("Loading image data pages (%u pages) ... ", nr_to_read); |
526 | m = nr_to_read / 100; | |
61159a31 RW |
527 | if (!m) |
528 | m = 1; | |
529 | nr_pages = 0; | |
546e0d27 | 530 | bio = NULL; |
8c002494 | 531 | do_gettimeofday(&start); |
546e0d27 AM |
532 | for ( ; ; ) { |
533 | error = snapshot_write_next(snapshot, PAGE_SIZE); | |
534 | if (error <= 0) | |
535 | break; | |
536 | error = swap_read_page(handle, data_of(*snapshot), &bio); | |
537 | if (error) | |
538 | break; | |
539 | if (snapshot->sync_read) | |
540 | error = wait_on_bio_chain(&bio); | |
541 | if (error) | |
542 | break; | |
543 | if (!(nr_pages % m)) | |
544 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
545 | nr_pages++; | |
546 | } | |
547 | err2 = wait_on_bio_chain(&bio); | |
8c002494 | 548 | do_gettimeofday(&stop); |
546e0d27 AM |
549 | if (!error) |
550 | error = err2; | |
e655a250 | 551 | if (!error) { |
61159a31 | 552 | printk("\b\b\b\bdone\n"); |
940864dd | 553 | snapshot_free_unused_memory(snapshot); |
e655a250 CK |
554 | if (!snapshot_image_loaded(snapshot)) |
555 | error = -ENODATA; | |
556 | } | |
546e0d27 | 557 | show_speed(&start, &stop, nr_to_read, "Read"); |
61159a31 RW |
558 | return error; |
559 | } | |
560 | ||
561 | int swsusp_read(void) | |
562 | { | |
563 | int error; | |
564 | struct swap_map_handle handle; | |
565 | struct snapshot_handle snapshot; | |
566 | struct swsusp_info *header; | |
567 | ||
568 | if (IS_ERR(resume_bdev)) { | |
569 | pr_debug("swsusp: block device not initialised\n"); | |
570 | return PTR_ERR(resume_bdev); | |
571 | } | |
572 | ||
573 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
574 | error = snapshot_write_next(&snapshot, PAGE_SIZE); | |
575 | if (error < PAGE_SIZE) | |
576 | return error < 0 ? error : -EFAULT; | |
577 | header = (struct swsusp_info *)data_of(snapshot); | |
578 | error = get_swap_reader(&handle, swsusp_header.image); | |
579 | if (!error) | |
546e0d27 | 580 | error = swap_read_page(&handle, header, NULL); |
61159a31 RW |
581 | if (!error) |
582 | error = load_image(&handle, &snapshot, header->pages - 1); | |
583 | release_swap_reader(&handle); | |
584 | ||
585 | blkdev_put(resume_bdev); | |
586 | ||
587 | if (!error) | |
588 | pr_debug("swsusp: Reading resume file was successful\n"); | |
589 | else | |
590 | pr_debug("swsusp: Error %d resuming\n", error); | |
591 | return error; | |
592 | } | |
593 | ||
594 | /** | |
595 | * swsusp_check - Check for swsusp signature in the resume device | |
596 | */ | |
597 | ||
598 | int swsusp_check(void) | |
599 | { | |
600 | int error; | |
601 | ||
602 | resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); | |
603 | if (!IS_ERR(resume_bdev)) { | |
604 | set_blocksize(resume_bdev, PAGE_SIZE); | |
605 | memset(&swsusp_header, 0, sizeof(swsusp_header)); | |
546e0d27 | 606 | if ((error = bio_read_page(0, &swsusp_header, NULL))) |
61159a31 RW |
607 | return error; |
608 | if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) { | |
609 | memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10); | |
610 | /* Reset swap signature now */ | |
611 | error = bio_write_page(0, &swsusp_header); | |
612 | } else { | |
613 | return -EINVAL; | |
614 | } | |
615 | if (error) | |
616 | blkdev_put(resume_bdev); | |
617 | else | |
618 | pr_debug("swsusp: Signature found, resuming\n"); | |
619 | } else { | |
620 | error = PTR_ERR(resume_bdev); | |
621 | } | |
622 | ||
623 | if (error) | |
624 | pr_debug("swsusp: Error %d check for resume file\n", error); | |
625 | ||
626 | return error; | |
627 | } | |
628 | ||
629 | /** | |
630 | * swsusp_close - close swap device. | |
631 | */ | |
632 | ||
633 | void swsusp_close(void) | |
634 | { | |
635 | if (IS_ERR(resume_bdev)) { | |
636 | pr_debug("swsusp: block device not initialised\n"); | |
637 | return; | |
638 | } | |
639 | ||
640 | blkdev_put(resume_bdev); | |
641 | } |