acf79ac1cb6d5f13667916aac50fd81ddd3af04e
[linux-2.6.git] / kernel / power / swsusp.c
1 /*
2  * linux/kernel/power/swsusp.c
3  *
4  * This file is to realize architecture-independent
5  * machine suspend feature using pretty near only high-level routines
6  *
7  * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
8  * Copyright (C) 1998,2001-2004 Pavel Machek <pavel@suse.cz>
9  *
10  * This file is released under the GPLv2.
11  *
12  * I'd like to thank the following people for their work:
13  *
14  * Pavel Machek <pavel@ucw.cz>:
15  * Modifications, defectiveness pointing, being with me at the very beginning,
16  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
17  *
18  * Steve Doddi <dirk@loth.demon.co.uk>:
19  * Support the possibility of hardware state restoring.
20  *
21  * Raph <grey.havens@earthling.net>:
22  * Support for preserving states of network devices and virtual console
23  * (including X and svgatextmode)
24  *
25  * Kurt Garloff <garloff@suse.de>:
26  * Straightened the critical function in order to prevent compilers from
27  * playing tricks with local variables.
28  *
29  * Andreas Mohr <a.mohr@mailto.de>
30  *
31  * Alex Badea <vampire@go.ro>:
32  * Fixed runaway init
33  *
34  * Andreas Steinmetz <ast@domdv.de>:
35  * Added encrypted suspend option
36  *
37  * More state savers are welcome. Especially for the scsi layer...
38  *
39  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
40  */
41
42 #include <linux/module.h>
43 #include <linux/mm.h>
44 #include <linux/suspend.h>
45 #include <linux/smp_lock.h>
46 #include <linux/file.h>
47 #include <linux/utsname.h>
48 #include <linux/version.h>
49 #include <linux/delay.h>
50 #include <linux/reboot.h>
51 #include <linux/bitops.h>
52 #include <linux/vt_kern.h>
53 #include <linux/kbd_kern.h>
54 #include <linux/keyboard.h>
55 #include <linux/spinlock.h>
56 #include <linux/genhd.h>
57 #include <linux/kernel.h>
58 #include <linux/major.h>
59 #include <linux/swap.h>
60 #include <linux/pm.h>
61 #include <linux/device.h>
62 #include <linux/buffer_head.h>
63 #include <linux/swapops.h>
64 #include <linux/bootmem.h>
65 #include <linux/syscalls.h>
66 #include <linux/console.h>
67 #include <linux/highmem.h>
68 #include <linux/bio.h>
69 #include <linux/mount.h>
70
71 #include <asm/uaccess.h>
72 #include <asm/mmu_context.h>
73 #include <asm/pgtable.h>
74 #include <asm/tlbflush.h>
75 #include <asm/io.h>
76
77 #include <linux/random.h>
78 #include <linux/crypto.h>
79 #include <asm/scatterlist.h>
80
81 #include "power.h"
82
83 #define CIPHER "aes"
84 #define MAXKEY 32
85 #define MAXIV  32
86
87 /* References to section boundaries */
88 extern const void __nosave_begin, __nosave_end;
89
90 /* Variables to be preserved over suspend */
91 static int nr_copy_pages_check;
92
93 extern char resume_file[];
94
95 /* Local variables that should not be affected by save */
96 static unsigned int nr_copy_pages __nosavedata = 0;
97
98 /* Suspend pagedir is allocated before final copy, therefore it
99    must be freed after resume
100
101    Warning: this is evil. There are actually two pagedirs at time of
102    resume. One is "pagedir_save", which is empty frame allocated at
103    time of suspend, that must be freed. Second is "pagedir_nosave",
104    allocated at time of resume, that travels through memory not to
105    collide with anything.
106
107    Warning: this is even more evil than it seems. Pagedirs this file
108    talks about are completely different from page directories used by
109    MMU hardware.
110  */
111 suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
112 static suspend_pagedir_t *pagedir_save;
113
114 #define SWSUSP_SIG      "S1SUSPEND"
115
116 static struct swsusp_header {
117         char reserved[PAGE_SIZE - 20 - MAXKEY - MAXIV - sizeof(swp_entry_t)];
118         u8 key_iv[MAXKEY+MAXIV];
119         swp_entry_t swsusp_info;
120         char    orig_sig[10];
121         char    sig[10];
122 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
123
124 static struct swsusp_info swsusp_info;
125
126 /*
127  * XXX: We try to keep some more pages free so that I/O operations succeed
128  * without paging. Might this be more?
129  */
130 #define PAGES_FOR_IO    512
131
132 /*
133  * Saving part...
134  */
135
136 /* We memorize in swapfile_used what swap devices are used for suspension */
137 #define SWAPFILE_UNUSED    0
138 #define SWAPFILE_SUSPEND   1    /* This is the suspending device */
139 #define SWAPFILE_IGNORED   2    /* Those are other swap devices ignored for suspension */
140
141 static unsigned short swapfile_used[MAX_SWAPFILES];
142 static unsigned short root_swap;
143
144 static int write_page(unsigned long addr, swp_entry_t * loc);
145 static int bio_read_page(pgoff_t page_off, void * page);
146
147 static u8 key_iv[MAXKEY+MAXIV];
148
149 #ifdef CONFIG_SWSUSP_ENCRYPT
150
151 static int crypto_init(int mode, void **mem)
152 {
153         int error = 0;
154         int len;
155         char *modemsg;
156         struct crypto_tfm *tfm;
157
158         modemsg = mode ? "suspend not possible" : "resume not possible";
159
160         tfm = crypto_alloc_tfm(CIPHER, CRYPTO_TFM_MODE_CBC);
161         if(!tfm) {
162                 printk(KERN_ERR "swsusp: no tfm, %s\n", modemsg);
163                 error = -EINVAL;
164                 goto out;
165         }
166
167         if(MAXKEY < crypto_tfm_alg_min_keysize(tfm)) {
168                 printk(KERN_ERR "swsusp: key buffer too small, %s\n", modemsg);
169                 error = -ENOKEY;
170                 goto fail;
171         }
172
173         if (mode)
174                 get_random_bytes(key_iv, MAXKEY+MAXIV);
175
176         len = crypto_tfm_alg_max_keysize(tfm);
177         if (len > MAXKEY)
178                 len = MAXKEY;
179
180         if (crypto_cipher_setkey(tfm, key_iv, len)) {
181                 printk(KERN_ERR "swsusp: key setup failure, %s\n", modemsg);
182                 error = -EKEYREJECTED;
183                 goto fail;
184         }
185
186         len = crypto_tfm_alg_ivsize(tfm);
187
188         if (MAXIV < len) {
189                 printk(KERN_ERR "swsusp: iv buffer too small, %s\n", modemsg);
190                 error = -EOVERFLOW;
191                 goto fail;
192         }
193
194         crypto_cipher_set_iv(tfm, key_iv+MAXKEY, len);
195
196         *mem=(void *)tfm;
197
198         goto out;
199
200 fail:   crypto_free_tfm(tfm);
201 out:    return error;
202 }
203
204 static __inline__ void crypto_exit(void *mem)
205 {
206         crypto_free_tfm((struct crypto_tfm *)mem);
207 }
208
209 static __inline__ int crypto_write(struct pbe *p, void *mem)
210 {
211         int error = 0;
212         struct scatterlist src, dst;
213
214         src.page   = virt_to_page(p->address);
215         src.offset = 0;
216         src.length = PAGE_SIZE;
217         dst.page   = virt_to_page((void *)&swsusp_header);
218         dst.offset = 0;
219         dst.length = PAGE_SIZE;
220
221         error = crypto_cipher_encrypt((struct crypto_tfm *)mem, &dst, &src,
222                                         PAGE_SIZE);
223
224         if (!error)
225                 error = write_page((unsigned long)&swsusp_header,
226                                 &(p->swap_address));
227         return error;
228 }
229
230 static __inline__ int crypto_read(struct pbe *p, void *mem)
231 {
232         int error = 0;
233         struct scatterlist src, dst;
234
235         error = bio_read_page(swp_offset(p->swap_address), (void *)p->address);
236         if (!error) {
237                 src.offset = 0;
238                 src.length = PAGE_SIZE;
239                 dst.offset = 0;
240                 dst.length = PAGE_SIZE;
241                 src.page = dst.page = virt_to_page((void *)p->address);
242
243                 error = crypto_cipher_decrypt((struct crypto_tfm *)mem, &dst,
244                                                 &src, PAGE_SIZE);
245         }
246         return error;
247 }
248 #else
249 static __inline__ int crypto_init(int mode, void *mem)
250 {
251         return 0;
252 }
253
254 static __inline__ void crypto_exit(void *mem)
255 {
256 }
257
258 static __inline__ int crypto_write(struct pbe *p, void *mem)
259 {
260         return write_page(p->address, &(p->swap_address));
261 }
262
263 static __inline__ int crypto_read(struct pbe *p, void *mem)
264 {
265         return bio_read_page(swp_offset(p->swap_address), (void *)p->address);
266 }
267 #endif
268
269 static int mark_swapfiles(swp_entry_t prev)
270 {
271         int error;
272
273         rw_swap_page_sync(READ,
274                           swp_entry(root_swap, 0),
275                           virt_to_page((unsigned long)&swsusp_header));
276         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
277             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
278                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
279                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
280                 memcpy(swsusp_header.key_iv, key_iv, MAXKEY+MAXIV);
281                 swsusp_header.swsusp_info = prev;
282                 error = rw_swap_page_sync(WRITE,
283                                           swp_entry(root_swap, 0),
284                                           virt_to_page((unsigned long)
285                                                        &swsusp_header));
286         } else {
287                 pr_debug("swsusp: Partition is not swap space.\n");
288                 error = -ENODEV;
289         }
290         return error;
291 }
292
293 /*
294  * Check whether the swap device is the specified resume
295  * device, irrespective of whether they are specified by
296  * identical names.
297  *
298  * (Thus, device inode aliasing is allowed.  You can say /dev/hda4
299  * instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
300  * and they'll be considered the same device.  This is *necessary* for
301  * devfs, since the resume code can only recognize the form /dev/hda4,
302  * but the suspend code would see the long name.)
303  */
304 static int is_resume_device(const struct swap_info_struct *swap_info)
305 {
306         struct file *file = swap_info->swap_file;
307         struct inode *inode = file->f_dentry->d_inode;
308
309         return S_ISBLK(inode->i_mode) &&
310                 swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
311 }
312
313 static int swsusp_swap_check(void) /* This is called before saving image */
314 {
315         int i, len;
316
317         len=strlen(resume_file);
318         root_swap = 0xFFFF;
319
320         spin_lock(&swap_lock);
321         for (i=0; i<MAX_SWAPFILES; i++) {
322                 if (!(swap_info[i].flags & SWP_WRITEOK)) {
323                         swapfile_used[i]=SWAPFILE_UNUSED;
324                 } else {
325                         if (!len) {
326                                 printk(KERN_WARNING "resume= option should be used to set suspend device" );
327                                 if (root_swap == 0xFFFF) {
328                                         swapfile_used[i] = SWAPFILE_SUSPEND;
329                                         root_swap = i;
330                                 } else
331                                         swapfile_used[i] = SWAPFILE_IGNORED;
332                         } else {
333                                 /* we ignore all swap devices that are not the resume_file */
334                                 if (is_resume_device(&swap_info[i])) {
335                                         swapfile_used[i] = SWAPFILE_SUSPEND;
336                                         root_swap = i;
337                                 } else {
338                                         swapfile_used[i] = SWAPFILE_IGNORED;
339                                 }
340                         }
341                 }
342         }
343         spin_unlock(&swap_lock);
344         return (root_swap != 0xffff) ? 0 : -ENODEV;
345 }
346
347 /**
348  * This is called after saving image so modification
349  * will be lost after resume... and that's what we want.
350  * we make the device unusable. A new call to
351  * lock_swapdevices can unlock the devices.
352  */
353 static void lock_swapdevices(void)
354 {
355         int i;
356
357         spin_lock(&swap_lock);
358         for (i = 0; i< MAX_SWAPFILES; i++)
359                 if (swapfile_used[i] == SWAPFILE_IGNORED) {
360                         swap_info[i].flags ^= SWP_WRITEOK;
361                 }
362         spin_unlock(&swap_lock);
363 }
364
365 /**
366  *      write_page - Write one page to a fresh swap location.
367  *      @addr:  Address we're writing.
368  *      @loc:   Place to store the entry we used.
369  *
370  *      Allocate a new swap entry and 'sync' it. Note we discard -EIO
371  *      errors. That is an artifact left over from swsusp. It did not
372  *      check the return of rw_swap_page_sync() at all, since most pages
373  *      written back to swap would return -EIO.
374  *      This is a partial improvement, since we will at least return other
375  *      errors, though we need to eventually fix the damn code.
376  */
377 static int write_page(unsigned long addr, swp_entry_t * loc)
378 {
379         swp_entry_t entry;
380         int error = 0;
381
382         entry = get_swap_page();
383         if (swp_offset(entry) &&
384             swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
385                 error = rw_swap_page_sync(WRITE, entry,
386                                           virt_to_page(addr));
387                 if (error == -EIO)
388                         error = 0;
389                 if (!error)
390                         *loc = entry;
391         } else
392                 error = -ENOSPC;
393         return error;
394 }
395
396 /**
397  *      data_free - Free the swap entries used by the saved image.
398  *
399  *      Walk the list of used swap entries and free each one.
400  *      This is only used for cleanup when suspend fails.
401  */
402 static void data_free(void)
403 {
404         swp_entry_t entry;
405         struct pbe * p;
406
407         for_each_pbe(p, pagedir_nosave) {
408                 entry = p->swap_address;
409                 if (entry.val)
410                         swap_free(entry);
411                 else
412                         break;
413         }
414 }
415
416 /**
417  *      data_write - Write saved image to swap.
418  *
419  *      Walk the list of pages in the image and sync each one to swap.
420  */
421 static int data_write(void)
422 {
423         int error = 0, i = 0;
424         unsigned int mod = nr_copy_pages / 100;
425         struct pbe *p;
426         void *tfm;
427
428         if ((error = crypto_init(1, &tfm)))
429                 return error;
430
431         if (!mod)
432                 mod = 1;
433
434         printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
435         for_each_pbe (p, pagedir_nosave) {
436                 if (!(i%mod))
437                         printk( "\b\b\b\b%3d%%", i / mod );
438                 if ((error = crypto_write(p, tfm))) {
439                         crypto_exit(tfm);
440                         return error;
441                 }
442                 i++;
443         }
444         printk("\b\b\b\bdone\n");
445         crypto_exit(tfm);
446         return error;
447 }
448
449 static void dump_info(void)
450 {
451         pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
452         pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
453         pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
454         pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
455         pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
456         pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
457         pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
458         pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
459         pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
460         pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
461         pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
462 }
463
464 static void init_header(void)
465 {
466         memset(&swsusp_info, 0, sizeof(swsusp_info));
467         swsusp_info.version_code = LINUX_VERSION_CODE;
468         swsusp_info.num_physpages = num_physpages;
469         memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
470
471         swsusp_info.suspend_pagedir = pagedir_nosave;
472         swsusp_info.cpus = num_online_cpus();
473         swsusp_info.image_pages = nr_copy_pages;
474 }
475
476 static int close_swap(void)
477 {
478         swp_entry_t entry;
479         int error;
480
481         dump_info();
482         error = write_page((unsigned long)&swsusp_info, &entry);
483         if (!error) {
484                 printk( "S" );
485                 error = mark_swapfiles(entry);
486                 printk( "|\n" );
487         }
488         return error;
489 }
490
491 /**
492  *      free_pagedir_entries - Free pages used by the page directory.
493  *
494  *      This is used during suspend for error recovery.
495  */
496
497 static void free_pagedir_entries(void)
498 {
499         int i;
500
501         for (i = 0; i < swsusp_info.pagedir_pages; i++)
502                 swap_free(swsusp_info.pagedir[i]);
503 }
504
505
506 /**
507  *      write_pagedir - Write the array of pages holding the page directory.
508  *      @last:  Last swap entry we write (needed for header).
509  */
510
511 static int write_pagedir(void)
512 {
513         int error = 0;
514         unsigned n = 0;
515         struct pbe * pbe;
516
517         printk( "Writing pagedir...");
518         for_each_pb_page (pbe, pagedir_nosave) {
519                 if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
520                         return error;
521         }
522
523         swsusp_info.pagedir_pages = n;
524         printk("done (%u pages)\n", n);
525         return error;
526 }
527
528 /**
529  *      write_suspend_image - Write entire image and metadata.
530  *
531  */
532 static int write_suspend_image(void)
533 {
534         int error;
535
536         init_header();
537         if ((error = data_write()))
538                 goto FreeData;
539
540         if ((error = write_pagedir()))
541                 goto FreePagedir;
542
543         if ((error = close_swap()))
544                 goto FreePagedir;
545  Done:
546         memset(key_iv, 0, MAXKEY+MAXIV);
547         return error;
548  FreePagedir:
549         free_pagedir_entries();
550  FreeData:
551         data_free();
552         goto Done;
553 }
554
555
556 #ifdef CONFIG_HIGHMEM
557 struct highmem_page {
558         char *data;
559         struct page *page;
560         struct highmem_page *next;
561 };
562
563 static struct highmem_page *highmem_copy;
564
565 static int save_highmem_zone(struct zone *zone)
566 {
567         unsigned long zone_pfn;
568         mark_free_pages(zone);
569         for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
570                 struct page *page;
571                 struct highmem_page *save;
572                 void *kaddr;
573                 unsigned long pfn = zone_pfn + zone->zone_start_pfn;
574
575                 if (!(pfn%1000))
576                         printk(".");
577                 if (!pfn_valid(pfn))
578                         continue;
579                 page = pfn_to_page(pfn);
580                 /*
581                  * This condition results from rvmalloc() sans vmalloc_32()
582                  * and architectural memory reservations. This should be
583                  * corrected eventually when the cases giving rise to this
584                  * are better understood.
585                  */
586                 if (PageReserved(page)) {
587                         printk("highmem reserved page?!\n");
588                         continue;
589                 }
590                 BUG_ON(PageNosave(page));
591                 if (PageNosaveFree(page))
592                         continue;
593                 save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
594                 if (!save)
595                         return -ENOMEM;
596                 save->next = highmem_copy;
597                 save->page = page;
598                 save->data = (void *) get_zeroed_page(GFP_ATOMIC);
599                 if (!save->data) {
600                         kfree(save);
601                         return -ENOMEM;
602                 }
603                 kaddr = kmap_atomic(page, KM_USER0);
604                 memcpy(save->data, kaddr, PAGE_SIZE);
605                 kunmap_atomic(kaddr, KM_USER0);
606                 highmem_copy = save;
607         }
608         return 0;
609 }
610 #endif /* CONFIG_HIGHMEM */
611
612
613 static int save_highmem(void)
614 {
615 #ifdef CONFIG_HIGHMEM
616         struct zone *zone;
617         int res = 0;
618
619         pr_debug("swsusp: Saving Highmem\n");
620         for_each_zone (zone) {
621                 if (is_highmem(zone))
622                         res = save_highmem_zone(zone);
623                 if (res)
624                         return res;
625         }
626 #endif
627         return 0;
628 }
629
630 static int restore_highmem(void)
631 {
632 #ifdef CONFIG_HIGHMEM
633         printk("swsusp: Restoring Highmem\n");
634         while (highmem_copy) {
635                 struct highmem_page *save = highmem_copy;
636                 void *kaddr;
637                 highmem_copy = save->next;
638
639                 kaddr = kmap_atomic(save->page, KM_USER0);
640                 memcpy(kaddr, save->data, PAGE_SIZE);
641                 kunmap_atomic(kaddr, KM_USER0);
642                 free_page((long) save->data);
643                 kfree(save);
644         }
645 #endif
646         return 0;
647 }
648
649
650 static int pfn_is_nosave(unsigned long pfn)
651 {
652         unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
653         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
654         return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
655 }
656
657 /**
658  *      saveable - Determine whether a page should be cloned or not.
659  *      @pfn:   The page
660  *
661  *      We save a page if it's Reserved, and not in the range of pages
662  *      statically defined as 'unsaveable', or if it isn't reserved, and
663  *      isn't part of a free chunk of pages.
664  */
665
666 static int saveable(struct zone * zone, unsigned long * zone_pfn)
667 {
668         unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
669         struct page * page;
670
671         if (!pfn_valid(pfn))
672                 return 0;
673
674         page = pfn_to_page(pfn);
675         BUG_ON(PageReserved(page) && PageNosave(page));
676         if (PageNosave(page))
677                 return 0;
678         if (PageReserved(page) && pfn_is_nosave(pfn)) {
679                 pr_debug("[nosave pfn 0x%lx]", pfn);
680                 return 0;
681         }
682         if (PageNosaveFree(page))
683                 return 0;
684
685         return 1;
686 }
687
688 static void count_data_pages(void)
689 {
690         struct zone *zone;
691         unsigned long zone_pfn;
692
693         nr_copy_pages = 0;
694
695         for_each_zone (zone) {
696                 if (is_highmem(zone))
697                         continue;
698                 mark_free_pages(zone);
699                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
700                         nr_copy_pages += saveable(zone, &zone_pfn);
701         }
702 }
703
704
705 static void copy_data_pages(void)
706 {
707         struct zone *zone;
708         unsigned long zone_pfn;
709         struct pbe * pbe = pagedir_nosave;
710
711         pr_debug("copy_data_pages(): pages to copy: %d\n", nr_copy_pages);
712         for_each_zone (zone) {
713                 if (is_highmem(zone))
714                         continue;
715                 mark_free_pages(zone);
716                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
717                         if (saveable(zone, &zone_pfn)) {
718                                 struct page * page;
719                                 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
720                                 BUG_ON(!pbe);
721                                 pbe->orig_address = (long) page_address(page);
722                                 /* copy_page is not usable for copying task structs. */
723                                 memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
724                                 pbe = pbe->next;
725                         }
726                 }
727         }
728         BUG_ON(pbe);
729 }
730
731
732 /**
733  *      calc_nr - Determine the number of pages needed for a pbe list.
734  */
735
736 static int calc_nr(int nr_copy)
737 {
738         return nr_copy + (nr_copy+PBES_PER_PAGE-2)/(PBES_PER_PAGE-1);
739 }
740
741 /**
742  *      free_pagedir - free pages allocated with alloc_pagedir()
743  */
744
745 static inline void free_pagedir(struct pbe *pblist)
746 {
747         struct pbe *pbe;
748
749         while (pblist) {
750                 pbe = (pblist + PB_PAGE_SKIP)->next;
751                 free_page((unsigned long)pblist);
752                 pblist = pbe;
753         }
754 }
755
756 /**
757  *      fill_pb_page - Create a list of PBEs on a given memory page
758  */
759
760 static inline void fill_pb_page(struct pbe *pbpage)
761 {
762         struct pbe *p;
763
764         p = pbpage;
765         pbpage += PB_PAGE_SKIP;
766         do
767                 p->next = p + 1;
768         while (++p < pbpage);
769 }
770
771 /**
772  *      create_pbe_list - Create a list of PBEs on top of a given chain
773  *      of memory pages allocated with alloc_pagedir()
774  */
775
776 static void create_pbe_list(struct pbe *pblist, unsigned nr_pages)
777 {
778         struct pbe *pbpage, *p;
779         unsigned num = PBES_PER_PAGE;
780
781         for_each_pb_page (pbpage, pblist) {
782                 if (num >= nr_pages)
783                         break;
784
785                 fill_pb_page(pbpage);
786                 num += PBES_PER_PAGE;
787         }
788         if (pbpage) {
789                 for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
790                         p->next = p + 1;
791                 p->next = NULL;
792         }
793         pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
794 }
795
796 /**
797  *      alloc_pagedir - Allocate the page directory.
798  *
799  *      First, determine exactly how many pages we need and
800  *      allocate them.
801  *
802  *      We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
803  *      struct pbe elements (pbes) and the last element in the page points
804  *      to the next page.
805  *
806  *      On each page we set up a list of struct_pbe elements.
807  */
808
809 static struct pbe * alloc_pagedir(unsigned nr_pages)
810 {
811         unsigned num;
812         struct pbe *pblist, *pbe;
813
814         if (!nr_pages)
815                 return NULL;
816
817         pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
818         pblist = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
819         for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
820                         pbe = pbe->next, num += PBES_PER_PAGE) {
821                 pbe += PB_PAGE_SKIP;
822                 pbe->next = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
823         }
824         if (!pbe) { /* get_zeroed_page() failed */
825                 free_pagedir(pblist);
826                 pblist = NULL;
827         }
828         return pblist;
829 }
830
831 /**
832  *      free_image_pages - Free pages allocated for snapshot
833  */
834
835 static void free_image_pages(void)
836 {
837         struct pbe * p;
838
839         for_each_pbe (p, pagedir_save) {
840                 if (p->address) {
841                         ClearPageNosave(virt_to_page(p->address));
842                         free_page(p->address);
843                         p->address = 0;
844                 }
845         }
846 }
847
848 /**
849  *      alloc_image_pages - Allocate pages for the snapshot.
850  */
851
852 static int alloc_image_pages(void)
853 {
854         struct pbe * p;
855
856         for_each_pbe (p, pagedir_save) {
857                 p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
858                 if (!p->address)
859                         return -ENOMEM;
860                 SetPageNosave(virt_to_page(p->address));
861         }
862         return 0;
863 }
864
865 /* Free pages we allocated for suspend. Suspend pages are alocated
866  * before atomic copy, so we need to free them after resume.
867  */
868 void swsusp_free(void)
869 {
870         BUG_ON(PageNosave(virt_to_page(pagedir_save)));
871         BUG_ON(PageNosaveFree(virt_to_page(pagedir_save)));
872         free_image_pages();
873         free_pagedir(pagedir_save);
874 }
875
876
877 /**
878  *      enough_free_mem - Make sure we enough free memory to snapshot.
879  *
880  *      Returns TRUE or FALSE after checking the number of available
881  *      free pages.
882  */
883
884 static int enough_free_mem(void)
885 {
886         if (nr_free_pages() < (nr_copy_pages + PAGES_FOR_IO)) {
887                 pr_debug("swsusp: Not enough free pages: Have %d\n",
888                          nr_free_pages());
889                 return 0;
890         }
891         return 1;
892 }
893
894
895 /**
896  *      enough_swap - Make sure we have enough swap to save the image.
897  *
898  *      Returns TRUE or FALSE after checking the total amount of swap
899  *      space avaiable.
900  *
901  *      FIXME: si_swapinfo(&i) returns all swap devices information.
902  *      We should only consider resume_device.
903  */
904
905 static int enough_swap(void)
906 {
907         struct sysinfo i;
908
909         si_swapinfo(&i);
910         if (i.freeswap < (nr_copy_pages + PAGES_FOR_IO))  {
911                 pr_debug("swsusp: Not enough swap. Need %ld\n",i.freeswap);
912                 return 0;
913         }
914         return 1;
915 }
916
917 static int swsusp_alloc(void)
918 {
919         int error;
920
921         pagedir_nosave = NULL;
922         nr_copy_pages = calc_nr(nr_copy_pages);
923         nr_copy_pages_check = nr_copy_pages;
924
925         pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
926                  nr_copy_pages, PAGES_FOR_IO, nr_free_pages());
927
928         if (!enough_free_mem())
929                 return -ENOMEM;
930
931         if (!enough_swap())
932                 return -ENOSPC;
933
934         if (MAX_PBES < nr_copy_pages / PBES_PER_PAGE +
935             !!(nr_copy_pages % PBES_PER_PAGE))
936                 return -ENOSPC;
937
938         if (!(pagedir_save = alloc_pagedir(nr_copy_pages))) {
939                 printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
940                 return -ENOMEM;
941         }
942         create_pbe_list(pagedir_save, nr_copy_pages);
943         pagedir_nosave = pagedir_save;
944         if ((error = alloc_image_pages())) {
945                 printk(KERN_ERR "suspend: Allocating image pages failed.\n");
946                 swsusp_free();
947                 return error;
948         }
949
950         return 0;
951 }
952
953 static int suspend_prepare_image(void)
954 {
955         int error;
956
957         pr_debug("swsusp: critical section: \n");
958         if (save_highmem()) {
959                 printk(KERN_CRIT "Suspend machine: Not enough free pages for highmem\n");
960                 restore_highmem();
961                 return -ENOMEM;
962         }
963
964         drain_local_pages();
965         count_data_pages();
966         printk("swsusp: Need to copy %u pages\n", nr_copy_pages);
967
968         error = swsusp_alloc();
969         if (error)
970                 return error;
971
972         /* During allocating of suspend pagedir, new cold pages may appear.
973          * Kill them.
974          */
975         drain_local_pages();
976         copy_data_pages();
977
978         /*
979          * End of critical section. From now on, we can write to memory,
980          * but we should not touch disk. This specially means we must _not_
981          * touch swap space! Except we must write out our image of course.
982          */
983
984         printk("swsusp: critical section/: done (%d pages copied)\n", nr_copy_pages );
985         return 0;
986 }
987
988
989 /* It is important _NOT_ to umount filesystems at this point. We want
990  * them synced (in case something goes wrong) but we DO not want to mark
991  * filesystem clean: it is not. (And it does not matter, if we resume
992  * correctly, we'll mark system clean, anyway.)
993  */
994 int swsusp_write(void)
995 {
996         int error;
997         device_resume();
998         lock_swapdevices();
999         error = write_suspend_image();
1000         /* This will unlock ignored swap devices since writing is finished */
1001         lock_swapdevices();
1002         return error;
1003
1004 }
1005
1006
1007 extern asmlinkage int swsusp_arch_suspend(void);
1008 extern asmlinkage int swsusp_arch_resume(void);
1009
1010
1011 asmlinkage int swsusp_save(void)
1012 {
1013         return suspend_prepare_image();
1014 }
1015
1016 int swsusp_suspend(void)
1017 {
1018         int error;
1019         if ((error = arch_prepare_suspend()))
1020                 return error;
1021         local_irq_disable();
1022         /* At this point, device_suspend() has been called, but *not*
1023          * device_power_down(). We *must* device_power_down() now.
1024          * Otherwise, drivers for some devices (e.g. interrupt controllers)
1025          * become desynchronized with the actual state of the hardware
1026          * at resume time, and evil weirdness ensues.
1027          */
1028         if ((error = device_power_down(PMSG_FREEZE))) {
1029                 printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
1030                 local_irq_enable();
1031                 return error;
1032         }
1033
1034         if ((error = swsusp_swap_check())) {
1035                 printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
1036                 device_power_up();
1037                 local_irq_enable();
1038                 return error;
1039         }
1040
1041         save_processor_state();
1042         if ((error = swsusp_arch_suspend()))
1043                 printk(KERN_ERR "Error %d suspending\n", error);
1044         /* Restore control flow magically appears here */
1045         restore_processor_state();
1046         BUG_ON (nr_copy_pages_check != nr_copy_pages);
1047         restore_highmem();
1048         device_power_up();
1049         local_irq_enable();
1050         return error;
1051 }
1052
1053 int swsusp_resume(void)
1054 {
1055         int error;
1056         local_irq_disable();
1057         if (device_power_down(PMSG_FREEZE))
1058                 printk(KERN_ERR "Some devices failed to power down, very bad\n");
1059         /* We'll ignore saved state, but this gets preempt count (etc) right */
1060         save_processor_state();
1061         error = swsusp_arch_resume();
1062         /* Code below is only ever reached in case of failure. Otherwise
1063          * execution continues at place where swsusp_arch_suspend was called
1064          */
1065         BUG_ON(!error);
1066         restore_processor_state();
1067         restore_highmem();
1068         touch_softlockup_watchdog();
1069         device_power_up();
1070         local_irq_enable();
1071         return error;
1072 }
1073
1074 /**
1075  *      On resume, for storing the PBE list and the image,
1076  *      we can only use memory pages that do not conflict with the pages
1077  *      which had been used before suspend.
1078  *
1079  *      We don't know which pages are usable until we allocate them.
1080  *
1081  *      Allocated but unusable (ie eaten) memory pages are linked together
1082  *      to create a list, so that we can free them easily
1083  *
1084  *      We could have used a type other than (void *)
1085  *      for this purpose, but ...
1086  */
1087 static void **eaten_memory = NULL;
1088
1089 static inline void eat_page(void *page)
1090 {
1091         void **c;
1092
1093         c = eaten_memory;
1094         eaten_memory = page;
1095         *eaten_memory = c;
1096 }
1097
1098 static unsigned long get_usable_page(unsigned gfp_mask)
1099 {
1100         unsigned long m;
1101
1102         m = get_zeroed_page(gfp_mask);
1103         while (!PageNosaveFree(virt_to_page(m))) {
1104                 eat_page((void *)m);
1105                 m = get_zeroed_page(gfp_mask);
1106                 if (!m)
1107                         break;
1108         }
1109         return m;
1110 }
1111
1112 static void free_eaten_memory(void)
1113 {
1114         unsigned long m;
1115         void **c;
1116         int i = 0;
1117
1118         c = eaten_memory;
1119         while (c) {
1120                 m = (unsigned long)c;
1121                 c = *c;
1122                 free_page(m);
1123                 i++;
1124         }
1125         eaten_memory = NULL;
1126         pr_debug("swsusp: %d unused pages freed\n", i);
1127 }
1128
1129 /**
1130  *      check_pagedir - We ensure here that pages that the PBEs point to
1131  *      won't collide with pages where we're going to restore from the loaded
1132  *      pages later
1133  */
1134
1135 static int check_pagedir(struct pbe *pblist)
1136 {
1137         struct pbe *p;
1138
1139         /* This is necessary, so that we can free allocated pages
1140          * in case of failure
1141          */
1142         for_each_pbe (p, pblist)
1143                 p->address = 0UL;
1144
1145         for_each_pbe (p, pblist) {
1146                 p->address = get_usable_page(GFP_ATOMIC);
1147                 if (!p->address)
1148                         return -ENOMEM;
1149         }
1150         return 0;
1151 }
1152
1153 /**
1154  *      swsusp_pagedir_relocate - It is possible, that some memory pages
1155  *      occupied by the list of PBEs collide with pages where we're going to
1156  *      restore from the loaded pages later.  We relocate them here.
1157  */
1158
1159 static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
1160 {
1161         struct zone *zone;
1162         unsigned long zone_pfn;
1163         struct pbe *pbpage, *tail, *p;
1164         void *m;
1165         int rel = 0, error = 0;
1166
1167         if (!pblist) /* a sanity check */
1168                 return NULL;
1169
1170         pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
1171                         swsusp_info.pagedir_pages);
1172
1173         /* Set page flags */
1174
1175         for_each_zone (zone) {
1176                 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
1177                         SetPageNosaveFree(pfn_to_page(zone_pfn +
1178                                         zone->zone_start_pfn));
1179         }
1180
1181         /* Clear orig addresses */
1182
1183         for_each_pbe (p, pblist)
1184                 ClearPageNosaveFree(virt_to_page(p->orig_address));
1185
1186         tail = pblist + PB_PAGE_SKIP;
1187
1188         /* Relocate colliding pages */
1189
1190         for_each_pb_page (pbpage, pblist) {
1191                 if (!PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
1192                         m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
1193                         if (!m) {
1194                                 error = -ENOMEM;
1195                                 break;
1196                         }
1197                         memcpy(m, (void *)pbpage, PAGE_SIZE);
1198                         if (pbpage == pblist)
1199                                 pblist = (struct pbe *)m;
1200                         else
1201                                 tail->next = (struct pbe *)m;
1202
1203                         eat_page((void *)pbpage);
1204                         pbpage = (struct pbe *)m;
1205
1206                         /* We have to link the PBEs again */
1207
1208                         for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
1209                                 if (p->next) /* needed to save the end */
1210                                         p->next = p + 1;
1211
1212                         rel++;
1213                 }
1214                 tail = pbpage + PB_PAGE_SKIP;
1215         }
1216
1217         if (error) {
1218                 printk("\nswsusp: Out of memory\n\n");
1219                 free_pagedir(pblist);
1220                 free_eaten_memory();
1221                 pblist = NULL;
1222                 /* Is this even worth handling? It should never ever happen, and we
1223                    have just lost user's state, anyway... */
1224         } else
1225                 printk("swsusp: Relocated %d pages\n", rel);
1226
1227         return pblist;
1228 }
1229
1230 /*
1231  *      Using bio to read from swap.
1232  *      This code requires a bit more work than just using buffer heads
1233  *      but, it is the recommended way for 2.5/2.6.
1234  *      The following are to signal the beginning and end of I/O. Bios
1235  *      finish asynchronously, while we want them to happen synchronously.
1236  *      A simple atomic_t, and a wait loop take care of this problem.
1237  */
1238
1239 static atomic_t io_done = ATOMIC_INIT(0);
1240
1241 static int end_io(struct bio * bio, unsigned int num, int err)
1242 {
1243         if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1244                 panic("I/O error reading memory image");
1245         atomic_set(&io_done, 0);
1246         return 0;
1247 }
1248
1249 static struct block_device * resume_bdev;
1250
1251 /**
1252  *      submit - submit BIO request.
1253  *      @rw:    READ or WRITE.
1254  *      @off    physical offset of page.
1255  *      @page:  page we're reading or writing.
1256  *
1257  *      Straight from the textbook - allocate and initialize the bio.
1258  *      If we're writing, make sure the page is marked as dirty.
1259  *      Then submit it and wait.
1260  */
1261
1262 static int submit(int rw, pgoff_t page_off, void * page)
1263 {
1264         int error = 0;
1265         struct bio * bio;
1266
1267         bio = bio_alloc(GFP_ATOMIC, 1);
1268         if (!bio)
1269                 return -ENOMEM;
1270         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
1271         bio_get(bio);
1272         bio->bi_bdev = resume_bdev;
1273         bio->bi_end_io = end_io;
1274
1275         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
1276                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
1277                 error = -EFAULT;
1278                 goto Done;
1279         }
1280
1281         if (rw == WRITE)
1282                 bio_set_pages_dirty(bio);
1283
1284         atomic_set(&io_done, 1);
1285         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
1286         while (atomic_read(&io_done))
1287                 yield();
1288
1289  Done:
1290         bio_put(bio);
1291         return error;
1292 }
1293
1294 static int bio_read_page(pgoff_t page_off, void * page)
1295 {
1296         return submit(READ, page_off, page);
1297 }
1298
1299 static int bio_write_page(pgoff_t page_off, void * page)
1300 {
1301         return submit(WRITE, page_off, page);
1302 }
1303
1304 /*
1305  * Sanity check if this image makes sense with this kernel/swap context
1306  * I really don't think that it's foolproof but more than nothing..
1307  */
1308
1309 static const char * sanity_check(void)
1310 {
1311         dump_info();
1312         if (swsusp_info.version_code != LINUX_VERSION_CODE)
1313                 return "kernel version";
1314         if (swsusp_info.num_physpages != num_physpages)
1315                 return "memory size";
1316         if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
1317                 return "system type";
1318         if (strcmp(swsusp_info.uts.release,system_utsname.release))
1319                 return "kernel release";
1320         if (strcmp(swsusp_info.uts.version,system_utsname.version))
1321                 return "version";
1322         if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
1323                 return "machine";
1324 #if 0
1325         /* We can't use number of online CPUs when we use hotplug to remove them ;-))) */
1326         if (swsusp_info.cpus != num_possible_cpus())
1327                 return "number of cpus";
1328 #endif
1329         return NULL;
1330 }
1331
1332
1333 static int check_header(void)
1334 {
1335         const char * reason = NULL;
1336         int error;
1337
1338         if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
1339                 return error;
1340
1341         /* Is this same machine? */
1342         if ((reason = sanity_check())) {
1343                 printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
1344                 return -EPERM;
1345         }
1346         nr_copy_pages = swsusp_info.image_pages;
1347         return error;
1348 }
1349
1350 static int check_sig(void)
1351 {
1352         int error;
1353
1354         memset(&swsusp_header, 0, sizeof(swsusp_header));
1355         if ((error = bio_read_page(0, &swsusp_header)))
1356                 return error;
1357         if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
1358                 memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
1359                 memcpy(key_iv, swsusp_header.key_iv, MAXKEY+MAXIV);
1360                 memset(swsusp_header.key_iv, 0, MAXKEY+MAXIV);
1361
1362                 /*
1363                  * Reset swap signature now.
1364                  */
1365                 error = bio_write_page(0, &swsusp_header);
1366         } else { 
1367                 return -EINVAL;
1368         }
1369         if (!error)
1370                 pr_debug("swsusp: Signature found, resuming\n");
1371         return error;
1372 }
1373
1374 /**
1375  *      data_read - Read image pages from swap.
1376  *
1377  *      You do not need to check for overlaps, check_pagedir()
1378  *      already did that.
1379  */
1380
1381 static int data_read(struct pbe *pblist)
1382 {
1383         struct pbe * p;
1384         int error = 0;
1385         int i = 0;
1386         int mod = swsusp_info.image_pages / 100;
1387         void *tfm;
1388
1389         if ((error = crypto_init(0, &tfm)))
1390                 return error;
1391
1392         if (!mod)
1393                 mod = 1;
1394
1395         printk("swsusp: Reading image data (%lu pages):     ",
1396                         swsusp_info.image_pages);
1397
1398         for_each_pbe (p, pblist) {
1399                 if (!(i % mod))
1400                         printk("\b\b\b\b%3d%%", i / mod);
1401
1402                 if ((error = crypto_read(p, tfm))) {
1403                         crypto_exit(tfm);
1404                         return error;
1405                 }
1406
1407                 i++;
1408         }
1409         printk("\b\b\b\bdone\n");
1410         crypto_exit(tfm);
1411         return error;
1412 }
1413
1414 /**
1415  *      read_pagedir - Read page backup list pages from swap
1416  */
1417
1418 static int read_pagedir(struct pbe *pblist)
1419 {
1420         struct pbe *pbpage, *p;
1421         unsigned i = 0;
1422         int error;
1423
1424         if (!pblist)
1425                 return -EFAULT;
1426
1427         printk("swsusp: Reading pagedir (%lu pages)\n",
1428                         swsusp_info.pagedir_pages);
1429
1430         for_each_pb_page (pbpage, pblist) {
1431                 unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
1432
1433                 error = -EFAULT;
1434                 if (offset) {
1435                         p = (pbpage + PB_PAGE_SKIP)->next;
1436                         error = bio_read_page(offset, (void *)pbpage);
1437                         (pbpage + PB_PAGE_SKIP)->next = p;
1438                 }
1439                 if (error)
1440                         break;
1441         }
1442
1443         if (error)
1444                 free_pagedir(pblist);
1445         else
1446                 BUG_ON(i != swsusp_info.pagedir_pages);
1447
1448         return error;
1449 }
1450
1451
1452 static int check_suspend_image(void)
1453 {
1454         int error = 0;
1455
1456         if ((error = check_sig()))
1457                 return error;
1458
1459         if ((error = check_header()))
1460                 return error;
1461
1462         return 0;
1463 }
1464
1465 static int read_suspend_image(void)
1466 {
1467         int error = 0;
1468         struct pbe *p;
1469
1470         if (!(p = alloc_pagedir(nr_copy_pages)))
1471                 return -ENOMEM;
1472
1473         if ((error = read_pagedir(p)))
1474                 return error;
1475
1476         create_pbe_list(p, nr_copy_pages);
1477
1478         if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
1479                 return -ENOMEM;
1480
1481         /* Allocate memory for the image and read the data from swap */
1482
1483         error = check_pagedir(pagedir_nosave);
1484         free_eaten_memory();
1485         if (!error)
1486                 error = data_read(pagedir_nosave);
1487
1488         if (error) { /* We fail cleanly */
1489                 for_each_pbe (p, pagedir_nosave)
1490                         if (p->address) {
1491                                 free_page(p->address);
1492                                 p->address = 0UL;
1493                         }
1494                 free_pagedir(pagedir_nosave);
1495         }
1496         return error;
1497 }
1498
1499 /**
1500  *      swsusp_check - Check for saved image in swap
1501  */
1502
1503 int swsusp_check(void)
1504 {
1505         int error;
1506
1507         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
1508         if (!IS_ERR(resume_bdev)) {
1509                 set_blocksize(resume_bdev, PAGE_SIZE);
1510                 error = check_suspend_image();
1511                 if (error)
1512                     blkdev_put(resume_bdev);
1513         } else
1514                 error = PTR_ERR(resume_bdev);
1515
1516         if (!error)
1517                 pr_debug("swsusp: resume file found\n");
1518         else
1519                 pr_debug("swsusp: Error %d check for resume file\n", error);
1520         return error;
1521 }
1522
1523 /**
1524  *      swsusp_read - Read saved image from swap.
1525  */
1526
1527 int swsusp_read(void)
1528 {
1529         int error;
1530
1531         if (IS_ERR(resume_bdev)) {
1532                 pr_debug("swsusp: block device not initialised\n");
1533                 return PTR_ERR(resume_bdev);
1534         }
1535
1536         error = read_suspend_image();
1537         blkdev_put(resume_bdev);
1538         memset(key_iv, 0, MAXKEY+MAXIV);
1539
1540         if (!error)
1541                 pr_debug("swsusp: Reading resume file was successful\n");
1542         else
1543                 pr_debug("swsusp: Error %d resuming\n", error);
1544         return error;
1545 }
1546
1547 /**
1548  *      swsusp_close - close swap device.
1549  */
1550
1551 void swsusp_close(void)
1552 {
1553         if (IS_ERR(resume_bdev)) {
1554                 pr_debug("swsusp: block device not initialised\n");
1555                 return;
1556         }
1557
1558         blkdev_put(resume_bdev);
1559 }