power: Fix sizeof(PAGE_SIZE) typo
[sfrench/cifs-2.6.git] / kernel / power / swap.c
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/utsname.h>
17 #include <linux/version.h>
18 #include <linux/delay.h>
19 #include <linux/bitops.h>
20 #include <linux/genhd.h>
21 #include <linux/device.h>
22 #include <linux/buffer_head.h>
23 #include <linux/bio.h>
24 #include <linux/blkdev.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 struct swsusp_header {
36         char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
37         sector_t image;
38         char    orig_sig[10];
39         char    sig[10];
40 } __attribute__((packed));
41
42 static struct swsusp_header *swsusp_header;
43
44 /*
45  * General things
46  */
47
48 static unsigned short root_swap = 0xffff;
49 static struct block_device *resume_bdev;
50
51 /**
52  *      submit - submit BIO request.
53  *      @rw:    READ or WRITE.
54  *      @off    physical offset of page.
55  *      @page:  page we're reading or writing.
56  *      @bio_chain: list of pending biod (for async reading)
57  *
58  *      Straight from the textbook - allocate and initialize the bio.
59  *      If we're reading, make sure the page is marked as dirty.
60  *      Then submit it and, if @bio_chain == NULL, wait.
61  */
62 static int submit(int rw, pgoff_t page_off, struct page *page,
63                         struct bio **bio_chain)
64 {
65         struct bio *bio;
66
67         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
68         if (!bio)
69                 return -ENOMEM;
70         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
71         bio->bi_bdev = resume_bdev;
72         bio->bi_end_io = end_swap_bio_read;
73
74         if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
75                 printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
76                 bio_put(bio);
77                 return -EFAULT;
78         }
79
80         lock_page(page);
81         bio_get(bio);
82
83         if (bio_chain == NULL) {
84                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
85                 wait_on_page_locked(page);
86                 if (rw == READ)
87                         bio_set_pages_dirty(bio);
88                 bio_put(bio);
89         } else {
90                 if (rw == READ)
91                         get_page(page); /* These pages are freed later */
92                 bio->bi_private = *bio_chain;
93                 *bio_chain = bio;
94                 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
95         }
96         return 0;
97 }
98
99 static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
100 {
101         return submit(READ, page_off, virt_to_page(addr), bio_chain);
102 }
103
104 static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
105 {
106         return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
107 }
108
109 static int wait_on_bio_chain(struct bio **bio_chain)
110 {
111         struct bio *bio;
112         struct bio *next_bio;
113         int ret = 0;
114
115         if (bio_chain == NULL)
116                 return 0;
117
118         bio = *bio_chain;
119         if (bio == NULL)
120                 return 0;
121         while (bio) {
122                 struct page *page;
123
124                 next_bio = bio->bi_private;
125                 page = bio->bi_io_vec[0].bv_page;
126                 wait_on_page_locked(page);
127                 if (!PageUptodate(page) || PageError(page))
128                         ret = -EIO;
129                 put_page(page);
130                 bio_put(bio);
131                 bio = next_bio;
132         }
133         *bio_chain = NULL;
134         return ret;
135 }
136
137 /*
138  * Saving part
139  */
140
141 static int mark_swapfiles(sector_t start)
142 {
143         int error;
144
145         bio_read_page(swsusp_resume_block, swsusp_header, NULL);
146         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
147             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
148                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
149                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
150                 swsusp_header->image = start;
151                 error = bio_write_page(swsusp_resume_block,
152                                         swsusp_header, NULL);
153         } else {
154                 printk(KERN_ERR "swsusp: Swap header not found!\n");
155                 error = -ENODEV;
156         }
157         return error;
158 }
159
160 /**
161  *      swsusp_swap_check - check if the resume device is a swap device
162  *      and get its index (if so)
163  */
164
165 static int swsusp_swap_check(void) /* This is called before saving image */
166 {
167         int res;
168
169         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
170                         &resume_bdev);
171         if (res < 0)
172                 return res;
173
174         root_swap = res;
175         res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
176         if (res)
177                 return res;
178
179         res = set_blocksize(resume_bdev, PAGE_SIZE);
180         if (res < 0)
181                 blkdev_put(resume_bdev);
182
183         return res;
184 }
185
186 /**
187  *      write_page - Write one page to given swap location.
188  *      @buf:           Address we're writing.
189  *      @offset:        Offset of the swap page we're writing to.
190  *      @bio_chain:     Link the next write BIO here
191  */
192
193 static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
194 {
195         void *src;
196
197         if (!offset)
198                 return -ENOSPC;
199
200         if (bio_chain) {
201                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
202                 if (src) {
203                         memcpy(src, buf, PAGE_SIZE);
204                 } else {
205                         WARN_ON_ONCE(1);
206                         bio_chain = NULL;       /* Go synchronous */
207                         src = buf;
208                 }
209         } else {
210                 src = buf;
211         }
212         return bio_write_page(offset, src, bio_chain);
213 }
214
215 /*
216  *      The swap map is a data structure used for keeping track of each page
217  *      written to a swap partition.  It consists of many swap_map_page
218  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
219  *      These structures are stored on the swap and linked together with the
220  *      help of the .next_swap member.
221  *
222  *      The swap map is created during suspend.  The swap map pages are
223  *      allocated and populated one at a time, so we only need one memory
224  *      page to set up the entire structure.
225  *
226  *      During resume we also only need to use one swap_map_page structure
227  *      at a time.
228  */
229
230 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(sector_t) - 1)
231
232 struct swap_map_page {
233         sector_t entries[MAP_PAGE_ENTRIES];
234         sector_t next_swap;
235 };
236
237 /**
238  *      The swap_map_handle structure is used for handling swap in
239  *      a file-alike way
240  */
241
242 struct swap_map_handle {
243         struct swap_map_page *cur;
244         sector_t cur_swap;
245         unsigned int k;
246 };
247
248 static void release_swap_writer(struct swap_map_handle *handle)
249 {
250         if (handle->cur)
251                 free_page((unsigned long)handle->cur);
252         handle->cur = NULL;
253 }
254
255 static int get_swap_writer(struct swap_map_handle *handle)
256 {
257         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
258         if (!handle->cur)
259                 return -ENOMEM;
260         handle->cur_swap = alloc_swapdev_block(root_swap);
261         if (!handle->cur_swap) {
262                 release_swap_writer(handle);
263                 return -ENOSPC;
264         }
265         handle->k = 0;
266         return 0;
267 }
268
269 static int swap_write_page(struct swap_map_handle *handle, void *buf,
270                                 struct bio **bio_chain)
271 {
272         int error = 0;
273         sector_t offset;
274
275         if (!handle->cur)
276                 return -EINVAL;
277         offset = alloc_swapdev_block(root_swap);
278         error = write_page(buf, offset, bio_chain);
279         if (error)
280                 return error;
281         handle->cur->entries[handle->k++] = offset;
282         if (handle->k >= MAP_PAGE_ENTRIES) {
283                 error = wait_on_bio_chain(bio_chain);
284                 if (error)
285                         goto out;
286                 offset = alloc_swapdev_block(root_swap);
287                 if (!offset)
288                         return -ENOSPC;
289                 handle->cur->next_swap = offset;
290                 error = write_page(handle->cur, handle->cur_swap, NULL);
291                 if (error)
292                         goto out;
293                 memset(handle->cur, 0, PAGE_SIZE);
294                 handle->cur_swap = offset;
295                 handle->k = 0;
296         }
297  out:
298         return error;
299 }
300
301 static int flush_swap_writer(struct swap_map_handle *handle)
302 {
303         if (handle->cur && handle->cur_swap)
304                 return write_page(handle->cur, handle->cur_swap, NULL);
305         else
306                 return -EINVAL;
307 }
308
309 /**
310  *      save_image - save the suspend image data
311  */
312
313 static int save_image(struct swap_map_handle *handle,
314                       struct snapshot_handle *snapshot,
315                       unsigned int nr_to_write)
316 {
317         unsigned int m;
318         int ret;
319         int error = 0;
320         int nr_pages;
321         int err2;
322         struct bio *bio;
323         struct timeval start;
324         struct timeval stop;
325
326         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
327         m = nr_to_write / 100;
328         if (!m)
329                 m = 1;
330         nr_pages = 0;
331         bio = NULL;
332         do_gettimeofday(&start);
333         do {
334                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
335                 if (ret > 0) {
336                         error = swap_write_page(handle, data_of(*snapshot),
337                                                 &bio);
338                         if (error)
339                                 break;
340                         if (!(nr_pages % m))
341                                 printk("\b\b\b\b%3d%%", nr_pages / m);
342                         nr_pages++;
343                 }
344         } while (ret > 0);
345         err2 = wait_on_bio_chain(&bio);
346         do_gettimeofday(&stop);
347         if (!error)
348                 error = err2;
349         if (!error)
350                 printk("\b\b\b\bdone\n");
351         swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
352         return error;
353 }
354
355 /**
356  *      enough_swap - Make sure we have enough swap to save the image.
357  *
358  *      Returns TRUE or FALSE after checking the total amount of swap
359  *      space avaiable from the resume partition.
360  */
361
362 static int enough_swap(unsigned int nr_pages)
363 {
364         unsigned int free_swap = count_swap_pages(root_swap, 1);
365
366         pr_debug("swsusp: free swap pages: %u\n", free_swap);
367         return free_swap > nr_pages + PAGES_FOR_IO;
368 }
369
370 /**
371  *      swsusp_write - Write entire image and metadata.
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(void)
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 "swsusp: 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 "swsusp: 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("S");
418                         error = mark_swapfiles(start);
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();
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("Loading image data pages (%u pages) ...     ", nr_to_read);
508         m = nr_to_read / 100;
509         if (!m)
510                 m = 1;
511         nr_pages = 0;
512         bio = NULL;
513         do_gettimeofday(&start);
514         for ( ; ; ) {
515                 error = snapshot_write_next(snapshot, PAGE_SIZE);
516                 if (error <= 0)
517                         break;
518                 error = swap_read_page(handle, data_of(*snapshot), &bio);
519                 if (error)
520                         break;
521                 if (snapshot->sync_read)
522                         error = wait_on_bio_chain(&bio);
523                 if (error)
524                         break;
525                 if (!(nr_pages % m))
526                         printk("\b\b\b\b%3d%%", nr_pages / m);
527                 nr_pages++;
528         }
529         err2 = wait_on_bio_chain(&bio);
530         do_gettimeofday(&stop);
531         if (!error)
532                 error = err2;
533         if (!error) {
534                 printk("\b\b\b\bdone\n");
535                 snapshot_write_finalize(snapshot);
536                 if (!snapshot_image_loaded(snapshot))
537                         error = -ENODATA;
538         }
539         swsusp_show_speed(&start, &stop, nr_to_read, "Read");
540         return error;
541 }
542
543 int swsusp_read(void)
544 {
545         int error;
546         struct swap_map_handle handle;
547         struct snapshot_handle snapshot;
548         struct swsusp_info *header;
549
550         if (IS_ERR(resume_bdev)) {
551                 pr_debug("swsusp: block device not initialised\n");
552                 return PTR_ERR(resume_bdev);
553         }
554
555         memset(&snapshot, 0, sizeof(struct snapshot_handle));
556         error = snapshot_write_next(&snapshot, PAGE_SIZE);
557         if (error < PAGE_SIZE)
558                 return error < 0 ? error : -EFAULT;
559         header = (struct swsusp_info *)data_of(snapshot);
560         error = get_swap_reader(&handle, swsusp_header->image);
561         if (!error)
562                 error = swap_read_page(&handle, header, NULL);
563         if (!error)
564                 error = load_image(&handle, &snapshot, header->pages - 1);
565         release_swap_reader(&handle);
566
567         blkdev_put(resume_bdev);
568
569         if (!error)
570                 pr_debug("swsusp: Reading resume file was successful\n");
571         else
572                 pr_debug("swsusp: Error %d resuming\n", error);
573         return error;
574 }
575
576 /**
577  *      swsusp_check - Check for swsusp signature in the resume device
578  */
579
580 int swsusp_check(void)
581 {
582         int error;
583
584         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
585         if (!IS_ERR(resume_bdev)) {
586                 set_blocksize(resume_bdev, PAGE_SIZE);
587                 memset(swsusp_header, 0, PAGE_SIZE);
588                 error = bio_read_page(swsusp_resume_block,
589                                         swsusp_header, NULL);
590                 if (error)
591                         return error;
592
593                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
594                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
595                         /* Reset swap signature now */
596                         error = bio_write_page(swsusp_resume_block,
597                                                 swsusp_header, NULL);
598                 } else {
599                         return -EINVAL;
600                 }
601                 if (error)
602                         blkdev_put(resume_bdev);
603                 else
604                         pr_debug("swsusp: Signature found, resuming\n");
605         } else {
606                 error = PTR_ERR(resume_bdev);
607         }
608
609         if (error)
610                 pr_debug("swsusp: Error %d check for resume file\n", error);
611
612         return error;
613 }
614
615 /**
616  *      swsusp_close - close swap device.
617  */
618
619 void swsusp_close(void)
620 {
621         if (IS_ERR(resume_bdev)) {
622                 pr_debug("swsusp: block device not initialised\n");
623                 return;
624         }
625
626         blkdev_put(resume_bdev);
627 }
628
629 static int swsusp_header_init(void)
630 {
631         swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
632         if (!swsusp_header)
633                 panic("Could not allocate memory for swsusp_header\n");
634         return 0;
635 }
636
637 core_initcall(swsusp_header_init);