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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 | /* | |
44 | * Saving part... | |
45 | */ | |
46 | ||
47 | static unsigned short root_swap = 0xffff; | |
48 | ||
49 | static int mark_swapfiles(swp_entry_t start) | |
50 | { | |
51 | int error; | |
52 | ||
ab954160 AM |
53 | rw_swap_page_sync(READ, swp_entry(root_swap, 0), |
54 | virt_to_page((unsigned long)&swsusp_header), NULL); | |
61159a31 RW |
55 | if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) || |
56 | !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) { | |
57 | memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10); | |
58 | memcpy(swsusp_header.sig,SWSUSP_SIG, 10); | |
59 | swsusp_header.image = start; | |
ab954160 AM |
60 | error = rw_swap_page_sync(WRITE, swp_entry(root_swap, 0), |
61 | virt_to_page((unsigned long)&swsusp_header), | |
62 | NULL); | |
61159a31 RW |
63 | } else { |
64 | pr_debug("swsusp: Partition is not swap space.\n"); | |
65 | error = -ENODEV; | |
66 | } | |
67 | return error; | |
68 | } | |
69 | ||
70 | /** | |
71 | * swsusp_swap_check - check if the resume device is a swap device | |
72 | * and get its index (if so) | |
73 | */ | |
74 | ||
75 | static int swsusp_swap_check(void) /* This is called before saving image */ | |
76 | { | |
77 | int res = swap_type_of(swsusp_resume_device); | |
78 | ||
79 | if (res >= 0) { | |
80 | root_swap = res; | |
81 | return 0; | |
82 | } | |
83 | return res; | |
84 | } | |
85 | ||
86 | /** | |
87 | * write_page - Write one page to given swap location. | |
88 | * @buf: Address we're writing. | |
89 | * @offset: Offset of the swap page we're writing to. | |
ab954160 | 90 | * @bio_chain: Link the next write BIO here |
61159a31 RW |
91 | */ |
92 | ||
ab954160 | 93 | static int write_page(void *buf, unsigned long offset, struct bio **bio_chain) |
61159a31 RW |
94 | { |
95 | swp_entry_t entry; | |
96 | int error = -ENOSPC; | |
97 | ||
98 | if (offset) { | |
ab954160 AM |
99 | struct page *page = virt_to_page(buf); |
100 | ||
101 | if (bio_chain) { | |
102 | /* | |
103 | * Whether or not we successfully allocated a copy page, | |
104 | * we take a ref on the page here. It gets undone in | |
105 | * wait_on_bio_chain(). | |
106 | */ | |
107 | struct page *page_copy; | |
108 | page_copy = alloc_page(GFP_ATOMIC); | |
109 | if (page_copy == NULL) { | |
110 | WARN_ON_ONCE(1); | |
111 | bio_chain = NULL; /* Go synchronous */ | |
112 | get_page(page); | |
113 | } else { | |
114 | memcpy(page_address(page_copy), | |
115 | page_address(page), PAGE_SIZE); | |
116 | page = page_copy; | |
117 | } | |
118 | } | |
61159a31 | 119 | entry = swp_entry(root_swap, offset); |
ab954160 | 120 | error = rw_swap_page_sync(WRITE, entry, page, bio_chain); |
61159a31 RW |
121 | } |
122 | return error; | |
123 | } | |
124 | ||
125 | /* | |
126 | * The swap map is a data structure used for keeping track of each page | |
127 | * written to a swap partition. It consists of many swap_map_page | |
128 | * structures that contain each an array of MAP_PAGE_SIZE swap entries. | |
129 | * These structures are stored on the swap and linked together with the | |
130 | * help of the .next_swap member. | |
131 | * | |
132 | * The swap map is created during suspend. The swap map pages are | |
133 | * allocated and populated one at a time, so we only need one memory | |
134 | * page to set up the entire structure. | |
135 | * | |
136 | * During resume we also only need to use one swap_map_page structure | |
137 | * at a time. | |
138 | */ | |
139 | ||
140 | #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1) | |
141 | ||
142 | struct swap_map_page { | |
143 | unsigned long entries[MAP_PAGE_ENTRIES]; | |
144 | unsigned long next_swap; | |
145 | }; | |
146 | ||
147 | /** | |
148 | * The swap_map_handle structure is used for handling swap in | |
149 | * a file-alike way | |
150 | */ | |
151 | ||
152 | struct swap_map_handle { | |
153 | struct swap_map_page *cur; | |
154 | unsigned long cur_swap; | |
155 | struct bitmap_page *bitmap; | |
156 | unsigned int k; | |
157 | }; | |
158 | ||
159 | static void release_swap_writer(struct swap_map_handle *handle) | |
160 | { | |
161 | if (handle->cur) | |
162 | free_page((unsigned long)handle->cur); | |
163 | handle->cur = NULL; | |
164 | if (handle->bitmap) | |
165 | free_bitmap(handle->bitmap); | |
166 | handle->bitmap = NULL; | |
167 | } | |
168 | ||
3a4f7577 AM |
169 | static void show_speed(struct timeval *start, struct timeval *stop, |
170 | unsigned nr_pages, char *msg) | |
171 | { | |
172 | s64 elapsed_centisecs64; | |
173 | int centisecs; | |
174 | int k; | |
175 | int kps; | |
176 | ||
177 | elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start); | |
178 | do_div(elapsed_centisecs64, NSEC_PER_SEC / 100); | |
179 | centisecs = elapsed_centisecs64; | |
180 | if (centisecs == 0) | |
181 | centisecs = 1; /* avoid div-by-zero */ | |
182 | k = nr_pages * (PAGE_SIZE / 1024); | |
183 | kps = (k * 100) / centisecs; | |
184 | printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k, | |
185 | centisecs / 100, centisecs % 100, | |
186 | kps / 1000, (kps % 1000) / 10); | |
187 | } | |
188 | ||
61159a31 RW |
189 | static int get_swap_writer(struct swap_map_handle *handle) |
190 | { | |
191 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); | |
192 | if (!handle->cur) | |
193 | return -ENOMEM; | |
194 | handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0)); | |
195 | if (!handle->bitmap) { | |
196 | release_swap_writer(handle); | |
197 | return -ENOMEM; | |
198 | } | |
199 | handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap); | |
200 | if (!handle->cur_swap) { | |
201 | release_swap_writer(handle); | |
202 | return -ENOSPC; | |
203 | } | |
204 | handle->k = 0; | |
205 | return 0; | |
206 | } | |
207 | ||
ab954160 | 208 | static int wait_on_bio_chain(struct bio **bio_chain) |
61159a31 | 209 | { |
ab954160 AM |
210 | struct bio *bio; |
211 | struct bio *next_bio; | |
212 | int ret = 0; | |
213 | ||
214 | if (bio_chain == NULL) | |
215 | return 0; | |
216 | ||
217 | bio = *bio_chain; | |
546e0d27 AM |
218 | if (bio == NULL) |
219 | return 0; | |
ab954160 AM |
220 | while (bio) { |
221 | struct page *page; | |
222 | ||
223 | next_bio = bio->bi_private; | |
224 | page = bio->bi_io_vec[0].bv_page; | |
225 | wait_on_page_locked(page); | |
226 | if (!PageUptodate(page) || PageError(page)) | |
227 | ret = -EIO; | |
228 | put_page(page); | |
229 | bio_put(bio); | |
230 | bio = next_bio; | |
231 | } | |
232 | *bio_chain = NULL; | |
233 | return ret; | |
234 | } | |
235 | ||
236 | static int swap_write_page(struct swap_map_handle *handle, void *buf, | |
237 | struct bio **bio_chain) | |
238 | { | |
239 | int error = 0; | |
61159a31 RW |
240 | unsigned long offset; |
241 | ||
242 | if (!handle->cur) | |
243 | return -EINVAL; | |
244 | offset = alloc_swap_page(root_swap, handle->bitmap); | |
ab954160 | 245 | error = write_page(buf, offset, bio_chain); |
61159a31 RW |
246 | if (error) |
247 | return error; | |
248 | handle->cur->entries[handle->k++] = offset; | |
249 | if (handle->k >= MAP_PAGE_ENTRIES) { | |
ab954160 AM |
250 | error = wait_on_bio_chain(bio_chain); |
251 | if (error) | |
252 | goto out; | |
61159a31 RW |
253 | offset = alloc_swap_page(root_swap, handle->bitmap); |
254 | if (!offset) | |
255 | return -ENOSPC; | |
256 | handle->cur->next_swap = offset; | |
ab954160 | 257 | error = write_page(handle->cur, handle->cur_swap, NULL); |
61159a31 | 258 | if (error) |
ab954160 | 259 | goto out; |
61159a31 RW |
260 | memset(handle->cur, 0, PAGE_SIZE); |
261 | handle->cur_swap = offset; | |
262 | handle->k = 0; | |
263 | } | |
ab954160 AM |
264 | out: |
265 | return error; | |
61159a31 RW |
266 | } |
267 | ||
268 | static int flush_swap_writer(struct swap_map_handle *handle) | |
269 | { | |
270 | if (handle->cur && handle->cur_swap) | |
ab954160 | 271 | return write_page(handle->cur, handle->cur_swap, NULL); |
61159a31 RW |
272 | else |
273 | return -EINVAL; | |
274 | } | |
275 | ||
276 | /** | |
277 | * save_image - save the suspend image data | |
278 | */ | |
279 | ||
280 | static int save_image(struct swap_map_handle *handle, | |
281 | struct snapshot_handle *snapshot, | |
3a4f7577 | 282 | unsigned int nr_to_write) |
61159a31 RW |
283 | { |
284 | unsigned int m; | |
285 | int ret; | |
286 | int error = 0; | |
3a4f7577 | 287 | int nr_pages; |
ab954160 AM |
288 | int err2; |
289 | struct bio *bio; | |
3a4f7577 AM |
290 | struct timeval start; |
291 | struct timeval stop; | |
61159a31 | 292 | |
3a4f7577 AM |
293 | printk("Saving image data pages (%u pages) ... ", nr_to_write); |
294 | m = nr_to_write / 100; | |
61159a31 RW |
295 | if (!m) |
296 | m = 1; | |
297 | nr_pages = 0; | |
ab954160 | 298 | bio = NULL; |
3a4f7577 | 299 | do_gettimeofday(&start); |
61159a31 RW |
300 | do { |
301 | ret = snapshot_read_next(snapshot, PAGE_SIZE); | |
302 | if (ret > 0) { | |
ab954160 AM |
303 | error = swap_write_page(handle, data_of(*snapshot), |
304 | &bio); | |
61159a31 RW |
305 | if (error) |
306 | break; | |
307 | if (!(nr_pages % m)) | |
308 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
309 | nr_pages++; | |
310 | } | |
311 | } while (ret > 0); | |
ab954160 | 312 | err2 = wait_on_bio_chain(&bio); |
3a4f7577 | 313 | do_gettimeofday(&stop); |
ab954160 AM |
314 | if (!error) |
315 | error = err2; | |
61159a31 RW |
316 | if (!error) |
317 | printk("\b\b\b\bdone\n"); | |
3a4f7577 | 318 | show_speed(&start, &stop, nr_to_write, "Wrote"); |
61159a31 RW |
319 | return error; |
320 | } | |
321 | ||
322 | /** | |
323 | * enough_swap - Make sure we have enough swap to save the image. | |
324 | * | |
325 | * Returns TRUE or FALSE after checking the total amount of swap | |
326 | * space avaiable from the resume partition. | |
327 | */ | |
328 | ||
329 | static int enough_swap(unsigned int nr_pages) | |
330 | { | |
331 | unsigned int free_swap = count_swap_pages(root_swap, 1); | |
332 | ||
333 | pr_debug("swsusp: free swap pages: %u\n", free_swap); | |
940864dd | 334 | return free_swap > nr_pages + PAGES_FOR_IO; |
61159a31 RW |
335 | } |
336 | ||
337 | /** | |
338 | * swsusp_write - Write entire image and metadata. | |
339 | * | |
340 | * It is important _NOT_ to umount filesystems at this point. We want | |
341 | * them synced (in case something goes wrong) but we DO not want to mark | |
342 | * filesystem clean: it is not. (And it does not matter, if we resume | |
343 | * correctly, we'll mark system clean, anyway.) | |
344 | */ | |
345 | ||
346 | int swsusp_write(void) | |
347 | { | |
348 | struct swap_map_handle handle; | |
349 | struct snapshot_handle snapshot; | |
350 | struct swsusp_info *header; | |
61159a31 RW |
351 | int error; |
352 | ||
353 | if ((error = swsusp_swap_check())) { | |
546e0d27 AM |
354 | printk(KERN_ERR "swsusp: Cannot find swap device, try " |
355 | "swapon -a.\n"); | |
61159a31 RW |
356 | return error; |
357 | } | |
358 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
359 | error = snapshot_read_next(&snapshot, PAGE_SIZE); | |
360 | if (error < PAGE_SIZE) | |
361 | return error < 0 ? error : -EFAULT; | |
362 | header = (struct swsusp_info *)data_of(snapshot); | |
363 | if (!enough_swap(header->pages)) { | |
364 | printk(KERN_ERR "swsusp: Not enough free swap\n"); | |
365 | return -ENOSPC; | |
366 | } | |
367 | error = get_swap_writer(&handle); | |
368 | if (!error) { | |
712f403a | 369 | unsigned long start = handle.cur_swap; |
ab954160 | 370 | error = swap_write_page(&handle, header, NULL); |
712f403a AM |
371 | if (!error) |
372 | error = save_image(&handle, &snapshot, | |
373 | header->pages - 1); | |
374 | if (!error) { | |
375 | flush_swap_writer(&handle); | |
376 | printk("S"); | |
377 | error = mark_swapfiles(swp_entry(root_swap, start)); | |
378 | printk("|\n"); | |
379 | } | |
61159a31 RW |
380 | } |
381 | if (error) | |
382 | free_all_swap_pages(root_swap, handle.bitmap); | |
383 | release_swap_writer(&handle); | |
384 | return error; | |
385 | } | |
386 | ||
61159a31 RW |
387 | static struct block_device *resume_bdev; |
388 | ||
389 | /** | |
390 | * submit - submit BIO request. | |
391 | * @rw: READ or WRITE. | |
392 | * @off physical offset of page. | |
393 | * @page: page we're reading or writing. | |
546e0d27 | 394 | * @bio_chain: list of pending biod (for async reading) |
61159a31 RW |
395 | * |
396 | * Straight from the textbook - allocate and initialize the bio. | |
546e0d27 AM |
397 | * If we're reading, make sure the page is marked as dirty. |
398 | * Then submit it and, if @bio_chain == NULL, wait. | |
61159a31 | 399 | */ |
546e0d27 AM |
400 | static int submit(int rw, pgoff_t page_off, struct page *page, |
401 | struct bio **bio_chain) | |
61159a31 | 402 | { |
61159a31 RW |
403 | struct bio *bio; |
404 | ||
405 | bio = bio_alloc(GFP_ATOMIC, 1); | |
406 | if (!bio) | |
407 | return -ENOMEM; | |
408 | bio->bi_sector = page_off * (PAGE_SIZE >> 9); | |
409 | bio->bi_bdev = resume_bdev; | |
546e0d27 | 410 | bio->bi_end_io = end_swap_bio_read; |
61159a31 | 411 | |
546e0d27 AM |
412 | if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { |
413 | printk("swsusp: ERROR: adding page to bio at %ld\n", page_off); | |
414 | bio_put(bio); | |
415 | return -EFAULT; | |
61159a31 RW |
416 | } |
417 | ||
546e0d27 AM |
418 | lock_page(page); |
419 | bio_get(bio); | |
420 | ||
421 | if (bio_chain == NULL) { | |
422 | submit_bio(rw | (1 << BIO_RW_SYNC), bio); | |
423 | wait_on_page_locked(page); | |
424 | if (rw == READ) | |
425 | bio_set_pages_dirty(bio); | |
426 | bio_put(bio); | |
427 | } else { | |
428 | get_page(page); | |
429 | bio->bi_private = *bio_chain; | |
430 | *bio_chain = bio; | |
431 | submit_bio(rw | (1 << BIO_RW_SYNC), bio); | |
432 | } | |
433 | return 0; | |
61159a31 RW |
434 | } |
435 | ||
546e0d27 | 436 | static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain) |
61159a31 | 437 | { |
546e0d27 | 438 | return submit(READ, page_off, virt_to_page(addr), bio_chain); |
61159a31 RW |
439 | } |
440 | ||
546e0d27 | 441 | static int bio_write_page(pgoff_t page_off, void *addr) |
61159a31 | 442 | { |
546e0d27 | 443 | return submit(WRITE, page_off, virt_to_page(addr), NULL); |
61159a31 RW |
444 | } |
445 | ||
446 | /** | |
447 | * The following functions allow us to read data using a swap map | |
448 | * in a file-alike way | |
449 | */ | |
450 | ||
451 | static void release_swap_reader(struct swap_map_handle *handle) | |
452 | { | |
453 | if (handle->cur) | |
454 | free_page((unsigned long)handle->cur); | |
455 | handle->cur = NULL; | |
456 | } | |
457 | ||
458 | static int get_swap_reader(struct swap_map_handle *handle, | |
459 | swp_entry_t start) | |
460 | { | |
461 | int error; | |
462 | ||
463 | if (!swp_offset(start)) | |
464 | return -EINVAL; | |
465 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC); | |
466 | if (!handle->cur) | |
467 | return -ENOMEM; | |
546e0d27 | 468 | error = bio_read_page(swp_offset(start), handle->cur, NULL); |
61159a31 RW |
469 | if (error) { |
470 | release_swap_reader(handle); | |
471 | return error; | |
472 | } | |
473 | handle->k = 0; | |
474 | return 0; | |
475 | } | |
476 | ||
546e0d27 AM |
477 | static int swap_read_page(struct swap_map_handle *handle, void *buf, |
478 | struct bio **bio_chain) | |
61159a31 RW |
479 | { |
480 | unsigned long offset; | |
481 | int error; | |
482 | ||
483 | if (!handle->cur) | |
484 | return -EINVAL; | |
485 | offset = handle->cur->entries[handle->k]; | |
486 | if (!offset) | |
487 | return -EFAULT; | |
546e0d27 | 488 | error = bio_read_page(offset, buf, bio_chain); |
61159a31 RW |
489 | if (error) |
490 | return error; | |
491 | if (++handle->k >= MAP_PAGE_ENTRIES) { | |
546e0d27 | 492 | error = wait_on_bio_chain(bio_chain); |
61159a31 RW |
493 | handle->k = 0; |
494 | offset = handle->cur->next_swap; | |
495 | if (!offset) | |
496 | release_swap_reader(handle); | |
546e0d27 AM |
497 | else if (!error) |
498 | error = bio_read_page(offset, handle->cur, NULL); | |
61159a31 RW |
499 | } |
500 | return error; | |
501 | } | |
502 | ||
503 | /** | |
504 | * load_image - load the image using the swap map handle | |
505 | * @handle and the snapshot handle @snapshot | |
506 | * (assume there are @nr_pages pages to load) | |
507 | */ | |
508 | ||
509 | static int load_image(struct swap_map_handle *handle, | |
510 | struct snapshot_handle *snapshot, | |
546e0d27 | 511 | unsigned int nr_to_read) |
61159a31 RW |
512 | { |
513 | unsigned int m; | |
61159a31 | 514 | int error = 0; |
8c002494 AM |
515 | struct timeval start; |
516 | struct timeval stop; | |
546e0d27 AM |
517 | struct bio *bio; |
518 | int err2; | |
519 | unsigned nr_pages; | |
61159a31 | 520 | |
546e0d27 AM |
521 | printk("Loading image data pages (%u pages) ... ", nr_to_read); |
522 | m = nr_to_read / 100; | |
61159a31 RW |
523 | if (!m) |
524 | m = 1; | |
525 | nr_pages = 0; | |
546e0d27 | 526 | bio = NULL; |
8c002494 | 527 | do_gettimeofday(&start); |
546e0d27 AM |
528 | for ( ; ; ) { |
529 | error = snapshot_write_next(snapshot, PAGE_SIZE); | |
530 | if (error <= 0) | |
531 | break; | |
532 | error = swap_read_page(handle, data_of(*snapshot), &bio); | |
533 | if (error) | |
534 | break; | |
535 | if (snapshot->sync_read) | |
536 | error = wait_on_bio_chain(&bio); | |
537 | if (error) | |
538 | break; | |
539 | if (!(nr_pages % m)) | |
540 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
541 | nr_pages++; | |
542 | } | |
543 | err2 = wait_on_bio_chain(&bio); | |
8c002494 | 544 | do_gettimeofday(&stop); |
546e0d27 AM |
545 | if (!error) |
546 | error = err2; | |
e655a250 | 547 | if (!error) { |
61159a31 | 548 | printk("\b\b\b\bdone\n"); |
940864dd | 549 | snapshot_free_unused_memory(snapshot); |
e655a250 CK |
550 | if (!snapshot_image_loaded(snapshot)) |
551 | error = -ENODATA; | |
552 | } | |
546e0d27 | 553 | show_speed(&start, &stop, nr_to_read, "Read"); |
61159a31 RW |
554 | return error; |
555 | } | |
556 | ||
557 | int swsusp_read(void) | |
558 | { | |
559 | int error; | |
560 | struct swap_map_handle handle; | |
561 | struct snapshot_handle snapshot; | |
562 | struct swsusp_info *header; | |
563 | ||
564 | if (IS_ERR(resume_bdev)) { | |
565 | pr_debug("swsusp: block device not initialised\n"); | |
566 | return PTR_ERR(resume_bdev); | |
567 | } | |
568 | ||
569 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
570 | error = snapshot_write_next(&snapshot, PAGE_SIZE); | |
571 | if (error < PAGE_SIZE) | |
572 | return error < 0 ? error : -EFAULT; | |
573 | header = (struct swsusp_info *)data_of(snapshot); | |
574 | error = get_swap_reader(&handle, swsusp_header.image); | |
575 | if (!error) | |
546e0d27 | 576 | error = swap_read_page(&handle, header, NULL); |
61159a31 RW |
577 | if (!error) |
578 | error = load_image(&handle, &snapshot, header->pages - 1); | |
579 | release_swap_reader(&handle); | |
580 | ||
581 | blkdev_put(resume_bdev); | |
582 | ||
583 | if (!error) | |
584 | pr_debug("swsusp: Reading resume file was successful\n"); | |
585 | else | |
586 | pr_debug("swsusp: Error %d resuming\n", error); | |
587 | return error; | |
588 | } | |
589 | ||
590 | /** | |
591 | * swsusp_check - Check for swsusp signature in the resume device | |
592 | */ | |
593 | ||
594 | int swsusp_check(void) | |
595 | { | |
596 | int error; | |
597 | ||
598 | resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); | |
599 | if (!IS_ERR(resume_bdev)) { | |
600 | set_blocksize(resume_bdev, PAGE_SIZE); | |
601 | memset(&swsusp_header, 0, sizeof(swsusp_header)); | |
546e0d27 | 602 | if ((error = bio_read_page(0, &swsusp_header, NULL))) |
61159a31 RW |
603 | return error; |
604 | if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) { | |
605 | memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10); | |
606 | /* Reset swap signature now */ | |
607 | error = bio_write_page(0, &swsusp_header); | |
608 | } else { | |
609 | return -EINVAL; | |
610 | } | |
611 | if (error) | |
612 | blkdev_put(resume_bdev); | |
613 | else | |
614 | pr_debug("swsusp: Signature found, resuming\n"); | |
615 | } else { | |
616 | error = PTR_ERR(resume_bdev); | |
617 | } | |
618 | ||
619 | if (error) | |
620 | pr_debug("swsusp: Error %d check for resume file\n", error); | |
621 | ||
622 | return error; | |
623 | } | |
624 | ||
625 | /** | |
626 | * swsusp_close - close swap device. | |
627 | */ | |
628 | ||
629 | void swsusp_close(void) | |
630 | { | |
631 | if (IS_ERR(resume_bdev)) { | |
632 | pr_debug("swsusp: block device not initialised\n"); | |
633 | return; | |
634 | } | |
635 | ||
636 | blkdev_put(resume_bdev); | |
637 | } |