]>
Commit | Line | Data |
---|---|---|
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> | |
25 | #include <linux/swap.h> | |
26 | #include <linux/swapops.h> | |
27 | #include <linux/pm.h> | |
28 | ||
29 | #include "power.h" | |
30 | ||
31 | extern char resume_file[]; | |
32 | ||
33 | #define SWSUSP_SIG "S1SUSPEND" | |
34 | ||
35 | static struct swsusp_header { | |
36 | char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)]; | |
37 | swp_entry_t image; | |
38 | char orig_sig[10]; | |
39 | char sig[10]; | |
40 | } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header; | |
41 | ||
42 | /* | |
43 | * Saving part... | |
44 | */ | |
45 | ||
46 | static unsigned short root_swap = 0xffff; | |
47 | ||
48 | static int mark_swapfiles(swp_entry_t start) | |
49 | { | |
50 | int error; | |
51 | ||
52 | rw_swap_page_sync(READ, | |
53 | swp_entry(root_swap, 0), | |
54 | virt_to_page((unsigned long)&swsusp_header)); | |
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; | |
60 | error = rw_swap_page_sync(WRITE, | |
61 | swp_entry(root_swap, 0), | |
62 | virt_to_page((unsigned long) | |
63 | &swsusp_header)); | |
64 | } else { | |
65 | pr_debug("swsusp: Partition is not swap space.\n"); | |
66 | error = -ENODEV; | |
67 | } | |
68 | return error; | |
69 | } | |
70 | ||
71 | /** | |
72 | * swsusp_swap_check - check if the resume device is a swap device | |
73 | * and get its index (if so) | |
74 | */ | |
75 | ||
76 | static int swsusp_swap_check(void) /* This is called before saving image */ | |
77 | { | |
78 | int res = swap_type_of(swsusp_resume_device); | |
79 | ||
80 | if (res >= 0) { | |
81 | root_swap = res; | |
82 | return 0; | |
83 | } | |
84 | return res; | |
85 | } | |
86 | ||
87 | /** | |
88 | * write_page - Write one page to given swap location. | |
89 | * @buf: Address we're writing. | |
90 | * @offset: Offset of the swap page we're writing to. | |
91 | */ | |
92 | ||
93 | static int write_page(void *buf, unsigned long offset) | |
94 | { | |
95 | swp_entry_t entry; | |
96 | int error = -ENOSPC; | |
97 | ||
98 | if (offset) { | |
99 | entry = swp_entry(root_swap, offset); | |
100 | error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf)); | |
101 | } | |
102 | return error; | |
103 | } | |
104 | ||
105 | /* | |
106 | * The swap map is a data structure used for keeping track of each page | |
107 | * written to a swap partition. It consists of many swap_map_page | |
108 | * structures that contain each an array of MAP_PAGE_SIZE swap entries. | |
109 | * These structures are stored on the swap and linked together with the | |
110 | * help of the .next_swap member. | |
111 | * | |
112 | * The swap map is created during suspend. The swap map pages are | |
113 | * allocated and populated one at a time, so we only need one memory | |
114 | * page to set up the entire structure. | |
115 | * | |
116 | * During resume we also only need to use one swap_map_page structure | |
117 | * at a time. | |
118 | */ | |
119 | ||
120 | #define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1) | |
121 | ||
122 | struct swap_map_page { | |
123 | unsigned long entries[MAP_PAGE_ENTRIES]; | |
124 | unsigned long next_swap; | |
125 | }; | |
126 | ||
127 | /** | |
128 | * The swap_map_handle structure is used for handling swap in | |
129 | * a file-alike way | |
130 | */ | |
131 | ||
132 | struct swap_map_handle { | |
133 | struct swap_map_page *cur; | |
134 | unsigned long cur_swap; | |
135 | struct bitmap_page *bitmap; | |
136 | unsigned int k; | |
137 | }; | |
138 | ||
139 | static void release_swap_writer(struct swap_map_handle *handle) | |
140 | { | |
141 | if (handle->cur) | |
142 | free_page((unsigned long)handle->cur); | |
143 | handle->cur = NULL; | |
144 | if (handle->bitmap) | |
145 | free_bitmap(handle->bitmap); | |
146 | handle->bitmap = NULL; | |
147 | } | |
148 | ||
149 | static int get_swap_writer(struct swap_map_handle *handle) | |
150 | { | |
151 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL); | |
152 | if (!handle->cur) | |
153 | return -ENOMEM; | |
154 | handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0)); | |
155 | if (!handle->bitmap) { | |
156 | release_swap_writer(handle); | |
157 | return -ENOMEM; | |
158 | } | |
159 | handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap); | |
160 | if (!handle->cur_swap) { | |
161 | release_swap_writer(handle); | |
162 | return -ENOSPC; | |
163 | } | |
164 | handle->k = 0; | |
165 | return 0; | |
166 | } | |
167 | ||
168 | static int swap_write_page(struct swap_map_handle *handle, void *buf) | |
169 | { | |
170 | int error; | |
171 | unsigned long offset; | |
172 | ||
173 | if (!handle->cur) | |
174 | return -EINVAL; | |
175 | offset = alloc_swap_page(root_swap, handle->bitmap); | |
176 | error = write_page(buf, offset); | |
177 | if (error) | |
178 | return error; | |
179 | handle->cur->entries[handle->k++] = offset; | |
180 | if (handle->k >= MAP_PAGE_ENTRIES) { | |
181 | offset = alloc_swap_page(root_swap, handle->bitmap); | |
182 | if (!offset) | |
183 | return -ENOSPC; | |
184 | handle->cur->next_swap = offset; | |
185 | error = write_page(handle->cur, handle->cur_swap); | |
186 | if (error) | |
187 | return error; | |
188 | memset(handle->cur, 0, PAGE_SIZE); | |
189 | handle->cur_swap = offset; | |
190 | handle->k = 0; | |
191 | } | |
192 | return 0; | |
193 | } | |
194 | ||
195 | static int flush_swap_writer(struct swap_map_handle *handle) | |
196 | { | |
197 | if (handle->cur && handle->cur_swap) | |
198 | return write_page(handle->cur, handle->cur_swap); | |
199 | else | |
200 | return -EINVAL; | |
201 | } | |
202 | ||
203 | /** | |
204 | * save_image - save the suspend image data | |
205 | */ | |
206 | ||
207 | static int save_image(struct swap_map_handle *handle, | |
208 | struct snapshot_handle *snapshot, | |
209 | unsigned int nr_pages) | |
210 | { | |
211 | unsigned int m; | |
212 | int ret; | |
213 | int error = 0; | |
214 | ||
215 | printk("Saving image data pages (%u pages) ... ", nr_pages); | |
216 | m = nr_pages / 100; | |
217 | if (!m) | |
218 | m = 1; | |
219 | nr_pages = 0; | |
220 | do { | |
221 | ret = snapshot_read_next(snapshot, PAGE_SIZE); | |
222 | if (ret > 0) { | |
223 | error = swap_write_page(handle, data_of(*snapshot)); | |
224 | if (error) | |
225 | break; | |
226 | if (!(nr_pages % m)) | |
227 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
228 | nr_pages++; | |
229 | } | |
230 | } while (ret > 0); | |
231 | if (!error) | |
232 | printk("\b\b\b\bdone\n"); | |
233 | return error; | |
234 | } | |
235 | ||
236 | /** | |
237 | * enough_swap - Make sure we have enough swap to save the image. | |
238 | * | |
239 | * Returns TRUE or FALSE after checking the total amount of swap | |
240 | * space avaiable from the resume partition. | |
241 | */ | |
242 | ||
243 | static int enough_swap(unsigned int nr_pages) | |
244 | { | |
245 | unsigned int free_swap = count_swap_pages(root_swap, 1); | |
246 | ||
247 | pr_debug("swsusp: free swap pages: %u\n", free_swap); | |
248 | return free_swap > (nr_pages + PAGES_FOR_IO + | |
249 | (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE); | |
250 | } | |
251 | ||
252 | /** | |
253 | * swsusp_write - Write entire image and metadata. | |
254 | * | |
255 | * It is important _NOT_ to umount filesystems at this point. We want | |
256 | * them synced (in case something goes wrong) but we DO not want to mark | |
257 | * filesystem clean: it is not. (And it does not matter, if we resume | |
258 | * correctly, we'll mark system clean, anyway.) | |
259 | */ | |
260 | ||
261 | int swsusp_write(void) | |
262 | { | |
263 | struct swap_map_handle handle; | |
264 | struct snapshot_handle snapshot; | |
265 | struct swsusp_info *header; | |
266 | unsigned long start; | |
267 | int error; | |
268 | ||
269 | if ((error = swsusp_swap_check())) { | |
270 | printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n"); | |
271 | return error; | |
272 | } | |
273 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
274 | error = snapshot_read_next(&snapshot, PAGE_SIZE); | |
275 | if (error < PAGE_SIZE) | |
276 | return error < 0 ? error : -EFAULT; | |
277 | header = (struct swsusp_info *)data_of(snapshot); | |
278 | if (!enough_swap(header->pages)) { | |
279 | printk(KERN_ERR "swsusp: Not enough free swap\n"); | |
280 | return -ENOSPC; | |
281 | } | |
282 | error = get_swap_writer(&handle); | |
283 | if (!error) { | |
284 | start = handle.cur_swap; | |
285 | error = swap_write_page(&handle, header); | |
286 | } | |
287 | if (!error) | |
288 | error = save_image(&handle, &snapshot, header->pages - 1); | |
289 | if (!error) { | |
290 | flush_swap_writer(&handle); | |
291 | printk("S"); | |
292 | error = mark_swapfiles(swp_entry(root_swap, start)); | |
293 | printk("|\n"); | |
294 | } | |
295 | if (error) | |
296 | free_all_swap_pages(root_swap, handle.bitmap); | |
297 | release_swap_writer(&handle); | |
298 | return error; | |
299 | } | |
300 | ||
301 | /* | |
302 | * Using bio to read from swap. | |
303 | * This code requires a bit more work than just using buffer heads | |
304 | * but, it is the recommended way for 2.5/2.6. | |
305 | * The following are to signal the beginning and end of I/O. Bios | |
306 | * finish asynchronously, while we want them to happen synchronously. | |
307 | * A simple atomic_t, and a wait loop take care of this problem. | |
308 | */ | |
309 | ||
310 | static atomic_t io_done = ATOMIC_INIT(0); | |
311 | ||
312 | static int end_io(struct bio *bio, unsigned int num, int err) | |
313 | { | |
314 | if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
315 | panic("I/O error reading memory image"); | |
316 | atomic_set(&io_done, 0); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | static struct block_device *resume_bdev; | |
321 | ||
322 | /** | |
323 | * submit - submit BIO request. | |
324 | * @rw: READ or WRITE. | |
325 | * @off physical offset of page. | |
326 | * @page: page we're reading or writing. | |
327 | * | |
328 | * Straight from the textbook - allocate and initialize the bio. | |
329 | * If we're writing, make sure the page is marked as dirty. | |
330 | * Then submit it and wait. | |
331 | */ | |
332 | ||
333 | static int submit(int rw, pgoff_t page_off, void *page) | |
334 | { | |
335 | int error = 0; | |
336 | struct bio *bio; | |
337 | ||
338 | bio = bio_alloc(GFP_ATOMIC, 1); | |
339 | if (!bio) | |
340 | return -ENOMEM; | |
341 | bio->bi_sector = page_off * (PAGE_SIZE >> 9); | |
342 | bio->bi_bdev = resume_bdev; | |
343 | bio->bi_end_io = end_io; | |
344 | ||
345 | if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) { | |
346 | printk("swsusp: ERROR: adding page to bio at %ld\n",page_off); | |
347 | error = -EFAULT; | |
348 | goto Done; | |
349 | } | |
350 | ||
351 | atomic_set(&io_done, 1); | |
352 | submit_bio(rw | (1 << BIO_RW_SYNC), bio); | |
353 | while (atomic_read(&io_done)) | |
354 | yield(); | |
355 | if (rw == READ) | |
356 | bio_set_pages_dirty(bio); | |
357 | Done: | |
358 | bio_put(bio); | |
359 | return error; | |
360 | } | |
361 | ||
362 | static int bio_read_page(pgoff_t page_off, void *page) | |
363 | { | |
364 | return submit(READ, page_off, page); | |
365 | } | |
366 | ||
367 | static int bio_write_page(pgoff_t page_off, void *page) | |
368 | { | |
369 | return submit(WRITE, page_off, page); | |
370 | } | |
371 | ||
372 | /** | |
373 | * The following functions allow us to read data using a swap map | |
374 | * in a file-alike way | |
375 | */ | |
376 | ||
377 | static void release_swap_reader(struct swap_map_handle *handle) | |
378 | { | |
379 | if (handle->cur) | |
380 | free_page((unsigned long)handle->cur); | |
381 | handle->cur = NULL; | |
382 | } | |
383 | ||
384 | static int get_swap_reader(struct swap_map_handle *handle, | |
385 | swp_entry_t start) | |
386 | { | |
387 | int error; | |
388 | ||
389 | if (!swp_offset(start)) | |
390 | return -EINVAL; | |
391 | handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC); | |
392 | if (!handle->cur) | |
393 | return -ENOMEM; | |
394 | error = bio_read_page(swp_offset(start), handle->cur); | |
395 | if (error) { | |
396 | release_swap_reader(handle); | |
397 | return error; | |
398 | } | |
399 | handle->k = 0; | |
400 | return 0; | |
401 | } | |
402 | ||
403 | static int swap_read_page(struct swap_map_handle *handle, void *buf) | |
404 | { | |
405 | unsigned long offset; | |
406 | int error; | |
407 | ||
408 | if (!handle->cur) | |
409 | return -EINVAL; | |
410 | offset = handle->cur->entries[handle->k]; | |
411 | if (!offset) | |
412 | return -EFAULT; | |
413 | error = bio_read_page(offset, buf); | |
414 | if (error) | |
415 | return error; | |
416 | if (++handle->k >= MAP_PAGE_ENTRIES) { | |
417 | handle->k = 0; | |
418 | offset = handle->cur->next_swap; | |
419 | if (!offset) | |
420 | release_swap_reader(handle); | |
421 | else | |
422 | error = bio_read_page(offset, handle->cur); | |
423 | } | |
424 | return error; | |
425 | } | |
426 | ||
427 | /** | |
428 | * load_image - load the image using the swap map handle | |
429 | * @handle and the snapshot handle @snapshot | |
430 | * (assume there are @nr_pages pages to load) | |
431 | */ | |
432 | ||
433 | static int load_image(struct swap_map_handle *handle, | |
434 | struct snapshot_handle *snapshot, | |
435 | unsigned int nr_pages) | |
436 | { | |
437 | unsigned int m; | |
438 | int ret; | |
439 | int error = 0; | |
440 | ||
441 | printk("Loading image data pages (%u pages) ... ", nr_pages); | |
442 | m = nr_pages / 100; | |
443 | if (!m) | |
444 | m = 1; | |
445 | nr_pages = 0; | |
446 | do { | |
447 | ret = snapshot_write_next(snapshot, PAGE_SIZE); | |
448 | if (ret > 0) { | |
449 | error = swap_read_page(handle, data_of(*snapshot)); | |
450 | if (error) | |
451 | break; | |
452 | if (!(nr_pages % m)) | |
453 | printk("\b\b\b\b%3d%%", nr_pages / m); | |
454 | nr_pages++; | |
455 | } | |
456 | } while (ret > 0); | |
e655a250 | 457 | if (!error) { |
61159a31 | 458 | printk("\b\b\b\bdone\n"); |
e655a250 CK |
459 | if (!snapshot_image_loaded(snapshot)) |
460 | error = -ENODATA; | |
461 | } | |
61159a31 RW |
462 | return error; |
463 | } | |
464 | ||
465 | int swsusp_read(void) | |
466 | { | |
467 | int error; | |
468 | struct swap_map_handle handle; | |
469 | struct snapshot_handle snapshot; | |
470 | struct swsusp_info *header; | |
471 | ||
472 | if (IS_ERR(resume_bdev)) { | |
473 | pr_debug("swsusp: block device not initialised\n"); | |
474 | return PTR_ERR(resume_bdev); | |
475 | } | |
476 | ||
477 | memset(&snapshot, 0, sizeof(struct snapshot_handle)); | |
478 | error = snapshot_write_next(&snapshot, PAGE_SIZE); | |
479 | if (error < PAGE_SIZE) | |
480 | return error < 0 ? error : -EFAULT; | |
481 | header = (struct swsusp_info *)data_of(snapshot); | |
482 | error = get_swap_reader(&handle, swsusp_header.image); | |
483 | if (!error) | |
484 | error = swap_read_page(&handle, header); | |
485 | if (!error) | |
486 | error = load_image(&handle, &snapshot, header->pages - 1); | |
487 | release_swap_reader(&handle); | |
488 | ||
489 | blkdev_put(resume_bdev); | |
490 | ||
491 | if (!error) | |
492 | pr_debug("swsusp: Reading resume file was successful\n"); | |
493 | else | |
494 | pr_debug("swsusp: Error %d resuming\n", error); | |
495 | return error; | |
496 | } | |
497 | ||
498 | /** | |
499 | * swsusp_check - Check for swsusp signature in the resume device | |
500 | */ | |
501 | ||
502 | int swsusp_check(void) | |
503 | { | |
504 | int error; | |
505 | ||
506 | resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ); | |
507 | if (!IS_ERR(resume_bdev)) { | |
508 | set_blocksize(resume_bdev, PAGE_SIZE); | |
509 | memset(&swsusp_header, 0, sizeof(swsusp_header)); | |
510 | if ((error = bio_read_page(0, &swsusp_header))) | |
511 | return error; | |
512 | if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) { | |
513 | memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10); | |
514 | /* Reset swap signature now */ | |
515 | error = bio_write_page(0, &swsusp_header); | |
516 | } else { | |
517 | return -EINVAL; | |
518 | } | |
519 | if (error) | |
520 | blkdev_put(resume_bdev); | |
521 | else | |
522 | pr_debug("swsusp: Signature found, resuming\n"); | |
523 | } else { | |
524 | error = PTR_ERR(resume_bdev); | |
525 | } | |
526 | ||
527 | if (error) | |
528 | pr_debug("swsusp: Error %d check for resume file\n", error); | |
529 | ||
530 | return error; | |
531 | } | |
532 | ||
533 | /** | |
534 | * swsusp_close - close swap device. | |
535 | */ | |
536 | ||
537 | void swsusp_close(void) | |
538 | { | |
539 | if (IS_ERR(resume_bdev)) { | |
540 | pr_debug("swsusp: block device not initialised\n"); | |
541 | return; | |
542 | } | |
543 | ||
544 | blkdev_put(resume_bdev); | |
545 | } |