linux/kernel/power/swsusp.c

1011 lines
24 KiB
C

/*
* linux/kernel/power/swsusp.c
*
* This file provides code to write suspend image to swap and read it back.
*
* Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2.
*
* I'd like to thank the following people for their work:
*
* Pavel Machek <pavel@ucw.cz>:
* Modifications, defectiveness pointing, being with me at the very beginning,
* suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
*
* Steve Doddi <dirk@loth.demon.co.uk>:
* Support the possibility of hardware state restoring.
*
* Raph <grey.havens@earthling.net>:
* Support for preserving states of network devices and virtual console
* (including X and svgatextmode)
*
* Kurt Garloff <garloff@suse.de>:
* Straightened the critical function in order to prevent compilers from
* playing tricks with local variables.
*
* Andreas Mohr <a.mohr@mailto.de>
*
* Alex Badea <vampire@go.ro>:
* Fixed runaway init
*
* Andreas Steinmetz <ast@domdv.de>:
* Added encrypted suspend option
*
* More state savers are welcome. Especially for the scsi layer...
*
* For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/swap.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/buffer_head.h>
#include <linux/swapops.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/highmem.h>
#include <linux/bio.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include <linux/random.h>
#include <linux/crypto.h>
#include <asm/scatterlist.h>
#include "power.h"
#ifdef CONFIG_HIGHMEM
int save_highmem(void);
int restore_highmem(void);
#else
static int save_highmem(void) { return 0; }
static int restore_highmem(void) { return 0; }
#endif
#define CIPHER "aes"
#define MAXKEY 32
#define MAXIV 32
extern char resume_file[];
/* Local variables that should not be affected by save */
unsigned int nr_copy_pages __nosavedata = 0;
/* Suspend pagedir is allocated before final copy, therefore it
must be freed after resume
Warning: this is even more evil than it seems. Pagedirs this file
talks about are completely different from page directories used by
MMU hardware.
*/
suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
#define SWSUSP_SIG "S1SUSPEND"
static struct swsusp_header {
char reserved[PAGE_SIZE - 20 - MAXKEY - MAXIV - sizeof(swp_entry_t)];
u8 key_iv[MAXKEY+MAXIV];
swp_entry_t swsusp_info;
char orig_sig[10];
char sig[10];
} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
static struct swsusp_info swsusp_info;
/*
* Saving part...
*/
/* We memorize in swapfile_used what swap devices are used for suspension */
#define SWAPFILE_UNUSED 0
#define SWAPFILE_SUSPEND 1 /* This is the suspending device */
#define SWAPFILE_IGNORED 2 /* Those are other swap devices ignored for suspension */
static unsigned short swapfile_used[MAX_SWAPFILES];
static unsigned short root_swap;
static int write_page(unsigned long addr, swp_entry_t *loc);
static int bio_read_page(pgoff_t page_off, void *page);
static u8 key_iv[MAXKEY+MAXIV];
#ifdef CONFIG_SWSUSP_ENCRYPT
static int crypto_init(int mode, void **mem)
{
int error = 0;
int len;
char *modemsg;
struct crypto_tfm *tfm;
modemsg = mode ? "suspend not possible" : "resume not possible";
tfm = crypto_alloc_tfm(CIPHER, CRYPTO_TFM_MODE_CBC);
if(!tfm) {
printk(KERN_ERR "swsusp: no tfm, %s\n", modemsg);
error = -EINVAL;
goto out;
}
if(MAXKEY < crypto_tfm_alg_min_keysize(tfm)) {
printk(KERN_ERR "swsusp: key buffer too small, %s\n", modemsg);
error = -ENOKEY;
goto fail;
}
if (mode)
get_random_bytes(key_iv, MAXKEY+MAXIV);
len = crypto_tfm_alg_max_keysize(tfm);
if (len > MAXKEY)
len = MAXKEY;
if (crypto_cipher_setkey(tfm, key_iv, len)) {
printk(KERN_ERR "swsusp: key setup failure, %s\n", modemsg);
error = -EKEYREJECTED;
goto fail;
}
len = crypto_tfm_alg_ivsize(tfm);
if (MAXIV < len) {
printk(KERN_ERR "swsusp: iv buffer too small, %s\n", modemsg);
error = -EOVERFLOW;
goto fail;
}
crypto_cipher_set_iv(tfm, key_iv+MAXKEY, len);
*mem=(void *)tfm;
goto out;
fail: crypto_free_tfm(tfm);
out: return error;
}
static __inline__ void crypto_exit(void *mem)
{
crypto_free_tfm((struct crypto_tfm *)mem);
}
static __inline__ int crypto_write(struct pbe *p, void *mem)
{
int error = 0;
struct scatterlist src, dst;
src.page = virt_to_page(p->address);
src.offset = 0;
src.length = PAGE_SIZE;
dst.page = virt_to_page((void *)&swsusp_header);
dst.offset = 0;
dst.length = PAGE_SIZE;
error = crypto_cipher_encrypt((struct crypto_tfm *)mem, &dst, &src,
PAGE_SIZE);
if (!error)
error = write_page((unsigned long)&swsusp_header,
&(p->swap_address));
return error;
}
static __inline__ int crypto_read(struct pbe *p, void *mem)
{
int error = 0;
struct scatterlist src, dst;
error = bio_read_page(swp_offset(p->swap_address), (void *)p->address);
if (!error) {
src.offset = 0;
src.length = PAGE_SIZE;
dst.offset = 0;
dst.length = PAGE_SIZE;
src.page = dst.page = virt_to_page((void *)p->address);
error = crypto_cipher_decrypt((struct crypto_tfm *)mem, &dst,
&src, PAGE_SIZE);
}
return error;
}
#else
static __inline__ int crypto_init(int mode, void *mem)
{
return 0;
}
static __inline__ void crypto_exit(void *mem)
{
}
static __inline__ int crypto_write(struct pbe *p, void *mem)
{
return write_page(p->address, &(p->swap_address));
}
static __inline__ int crypto_read(struct pbe *p, void *mem)
{
return bio_read_page(swp_offset(p->swap_address), (void *)p->address);
}
#endif
static int mark_swapfiles(swp_entry_t prev)
{
int error;
rw_swap_page_sync(READ,
swp_entry(root_swap, 0),
virt_to_page((unsigned long)&swsusp_header));
if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
!memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
memcpy(swsusp_header.key_iv, key_iv, MAXKEY+MAXIV);
swsusp_header.swsusp_info = prev;
error = rw_swap_page_sync(WRITE,
swp_entry(root_swap, 0),
virt_to_page((unsigned long)
&swsusp_header));
} else {
pr_debug("swsusp: Partition is not swap space.\n");
error = -ENODEV;
}
return error;
}
/*
* Check whether the swap device is the specified resume
* device, irrespective of whether they are specified by
* identical names.
*
* (Thus, device inode aliasing is allowed. You can say /dev/hda4
* instead of /dev/ide/host0/bus0/target0/lun0/part4 [if using devfs]
* and they'll be considered the same device. This is *necessary* for
* devfs, since the resume code can only recognize the form /dev/hda4,
* but the suspend code would see the long name.)
*/
static int is_resume_device(const struct swap_info_struct *swap_info)
{
struct file *file = swap_info->swap_file;
struct inode *inode = file->f_dentry->d_inode;
return S_ISBLK(inode->i_mode) &&
swsusp_resume_device == MKDEV(imajor(inode), iminor(inode));
}
static int swsusp_swap_check(void) /* This is called before saving image */
{
int i, len;
len=strlen(resume_file);
root_swap = 0xFFFF;
spin_lock(&swap_lock);
for (i=0; i<MAX_SWAPFILES; i++) {
if (!(swap_info[i].flags & SWP_WRITEOK)) {
swapfile_used[i]=SWAPFILE_UNUSED;
} else {
if (!len) {
printk(KERN_WARNING "resume= option should be used to set suspend device" );
if (root_swap == 0xFFFF) {
swapfile_used[i] = SWAPFILE_SUSPEND;
root_swap = i;
} else
swapfile_used[i] = SWAPFILE_IGNORED;
} else {
/* we ignore all swap devices that are not the resume_file */
if (is_resume_device(&swap_info[i])) {
swapfile_used[i] = SWAPFILE_SUSPEND;
root_swap = i;
} else {
swapfile_used[i] = SWAPFILE_IGNORED;
}
}
}
}
spin_unlock(&swap_lock);
return (root_swap != 0xffff) ? 0 : -ENODEV;
}
/**
* This is called after saving image so modification
* will be lost after resume... and that's what we want.
* we make the device unusable. A new call to
* lock_swapdevices can unlock the devices.
*/
static void lock_swapdevices(void)
{
int i;
spin_lock(&swap_lock);
for (i = 0; i< MAX_SWAPFILES; i++)
if (swapfile_used[i] == SWAPFILE_IGNORED) {
swap_info[i].flags ^= SWP_WRITEOK;
}
spin_unlock(&swap_lock);
}
/**
* write_page - Write one page to a fresh swap location.
* @addr: Address we're writing.
* @loc: Place to store the entry we used.
*
* Allocate a new swap entry and 'sync' it. Note we discard -EIO
* errors. That is an artifact left over from swsusp. It did not
* check the return of rw_swap_page_sync() at all, since most pages
* written back to swap would return -EIO.
* This is a partial improvement, since we will at least return other
* errors, though we need to eventually fix the damn code.
*/
static int write_page(unsigned long addr, swp_entry_t *loc)
{
swp_entry_t entry;
int error = 0;
entry = get_swap_page();
if (swp_offset(entry) &&
swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
error = rw_swap_page_sync(WRITE, entry,
virt_to_page(addr));
if (error == -EIO)
error = 0;
if (!error)
*loc = entry;
} else
error = -ENOSPC;
return error;
}
/**
* data_free - Free the swap entries used by the saved image.
*
* Walk the list of used swap entries and free each one.
* This is only used for cleanup when suspend fails.
*/
static void data_free(void)
{
swp_entry_t entry;
struct pbe *p;
for_each_pbe (p, pagedir_nosave) {
entry = p->swap_address;
if (entry.val)
swap_free(entry);
else
break;
}
}
/**
* data_write - Write saved image to swap.
*
* Walk the list of pages in the image and sync each one to swap.
*/
static int data_write(void)
{
int error = 0, i = 0;
unsigned int mod = nr_copy_pages / 100;
struct pbe *p;
void *tfm;
if ((error = crypto_init(1, &tfm)))
return error;
if (!mod)
mod = 1;
printk( "Writing data to swap (%d pages)... ", nr_copy_pages );
for_each_pbe (p, pagedir_nosave) {
if (!(i%mod))
printk( "\b\b\b\b%3d%%", i / mod );
if ((error = crypto_write(p, tfm))) {
crypto_exit(tfm);
return error;
}
i++;
}
printk("\b\b\b\bdone\n");
crypto_exit(tfm);
return error;
}
static void dump_info(void)
{
pr_debug(" swsusp: Version: %u\n",swsusp_info.version_code);
pr_debug(" swsusp: Num Pages: %ld\n",swsusp_info.num_physpages);
pr_debug(" swsusp: UTS Sys: %s\n",swsusp_info.uts.sysname);
pr_debug(" swsusp: UTS Node: %s\n",swsusp_info.uts.nodename);
pr_debug(" swsusp: UTS Release: %s\n",swsusp_info.uts.release);
pr_debug(" swsusp: UTS Version: %s\n",swsusp_info.uts.version);
pr_debug(" swsusp: UTS Machine: %s\n",swsusp_info.uts.machine);
pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
}
static void init_header(void)
{
memset(&swsusp_info, 0, sizeof(swsusp_info));
swsusp_info.version_code = LINUX_VERSION_CODE;
swsusp_info.num_physpages = num_physpages;
memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
swsusp_info.suspend_pagedir = pagedir_nosave;
swsusp_info.cpus = num_online_cpus();
swsusp_info.image_pages = nr_copy_pages;
}
static int close_swap(void)
{
swp_entry_t entry;
int error;
dump_info();
error = write_page((unsigned long)&swsusp_info, &entry);
if (!error) {
printk( "S" );
error = mark_swapfiles(entry);
printk( "|\n" );
}
return error;
}
/**
* free_pagedir_entries - Free pages used by the page directory.
*
* This is used during suspend for error recovery.
*/
static void free_pagedir_entries(void)
{
int i;
for (i = 0; i < swsusp_info.pagedir_pages; i++)
swap_free(swsusp_info.pagedir[i]);
}
/**
* write_pagedir - Write the array of pages holding the page directory.
* @last: Last swap entry we write (needed for header).
*/
static int write_pagedir(void)
{
int error = 0;
unsigned int n = 0;
struct pbe *pbe;
printk( "Writing pagedir...");
for_each_pb_page (pbe, pagedir_nosave) {
if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
return error;
}
swsusp_info.pagedir_pages = n;
printk("done (%u pages)\n", n);
return error;
}
/**
* enough_swap - Make sure we have enough swap to save the image.
*
* Returns TRUE or FALSE after checking the total amount of swap
* space avaiable.
*
* FIXME: si_swapinfo(&i) returns all swap devices information.
* We should only consider resume_device.
*/
static int enough_swap(unsigned int nr_pages)
{
struct sysinfo i;
si_swapinfo(&i);
pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
return i.freeswap > (nr_pages + PAGES_FOR_IO +
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
/**
* write_suspend_image - Write entire image and metadata.
*
*/
static int write_suspend_image(void)
{
int error;
if (!enough_swap(nr_copy_pages)) {
printk(KERN_ERR "swsusp: Not enough free swap\n");
return -ENOSPC;
}
init_header();
if ((error = data_write()))
goto FreeData;
if ((error = write_pagedir()))
goto FreePagedir;
if ((error = close_swap()))
goto FreePagedir;
Done:
memset(key_iv, 0, MAXKEY+MAXIV);
return error;
FreePagedir:
free_pagedir_entries();
FreeData:
data_free();
goto Done;
}
/* It is important _NOT_ to umount filesystems at this point. We want
* them synced (in case something goes wrong) but we DO not want to mark
* filesystem clean: it is not. (And it does not matter, if we resume
* correctly, we'll mark system clean, anyway.)
*/
int swsusp_write(void)
{
int error;
if ((error = swsusp_swap_check())) {
printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
return error;
}
lock_swapdevices();
error = write_suspend_image();
/* This will unlock ignored swap devices since writing is finished */
lock_swapdevices();
return error;
}
int swsusp_suspend(void)
{
int error;
if ((error = arch_prepare_suspend()))
return error;
local_irq_disable();
/* At this point, device_suspend() has been called, but *not*
* device_power_down(). We *must* device_power_down() now.
* Otherwise, drivers for some devices (e.g. interrupt controllers)
* become desynchronized with the actual state of the hardware
* at resume time, and evil weirdness ensues.
*/
if ((error = device_power_down(PMSG_FREEZE))) {
printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
goto Enable_irqs;
}
if ((error = save_highmem())) {
printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
goto Restore_highmem;
}
save_processor_state();
if ((error = swsusp_arch_suspend()))
printk(KERN_ERR "Error %d suspending\n", error);
/* Restore control flow magically appears here */
restore_processor_state();
Restore_highmem:
restore_highmem();
device_power_up();
Enable_irqs:
local_irq_enable();
return error;
}
int swsusp_resume(void)
{
int error;
local_irq_disable();
if (device_power_down(PMSG_FREEZE))
printk(KERN_ERR "Some devices failed to power down, very bad\n");
/* We'll ignore saved state, but this gets preempt count (etc) right */
save_processor_state();
error = swsusp_arch_resume();
/* Code below is only ever reached in case of failure. Otherwise
* execution continues at place where swsusp_arch_suspend was called
*/
BUG_ON(!error);
/* The only reason why swsusp_arch_resume() can fail is memory being
* very tight, so we have to free it as soon as we can to avoid
* subsequent failures
*/
swsusp_free();
restore_processor_state();
restore_highmem();
touch_softlockup_watchdog();
device_power_up();
local_irq_enable();
return error;
}
/**
* mark_unsafe_pages - mark the pages that cannot be used for storing
* the image during resume, because they conflict with the pages that
* had been used before suspend
*/
static void mark_unsafe_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *p;
if (!pblist) /* a sanity check */
return;
/* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn))
ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
/* Mark orig addresses */
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->orig_address));
}
static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
{
/* We assume both lists contain the same number of elements */
while (src) {
dst->orig_address = src->orig_address;
dst->swap_address = src->swap_address;
dst = dst->next;
src = src->next;
}
}
/*
* Using bio to read from swap.
* This code requires a bit more work than just using buffer heads
* but, it is the recommended way for 2.5/2.6.
* The following are to signal the beginning and end of I/O. Bios
* finish asynchronously, while we want them to happen synchronously.
* A simple atomic_t, and a wait loop take care of this problem.
*/
static atomic_t io_done = ATOMIC_INIT(0);
static int end_io(struct bio *bio, unsigned int num, int err)
{
if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
panic("I/O error reading memory image");
atomic_set(&io_done, 0);
return 0;
}
static struct block_device *resume_bdev;
/**
* submit - submit BIO request.
* @rw: READ or WRITE.
* @off physical offset of page.
* @page: page we're reading or writing.
*
* Straight from the textbook - allocate and initialize the bio.
* If we're writing, make sure the page is marked as dirty.
* Then submit it and wait.
*/
static int submit(int rw, pgoff_t page_off, void *page)
{
int error = 0;
struct bio *bio;
bio = bio_alloc(GFP_ATOMIC, 1);
if (!bio)
return -ENOMEM;
bio->bi_sector = page_off * (PAGE_SIZE >> 9);
bio_get(bio);
bio->bi_bdev = resume_bdev;
bio->bi_end_io = end_io;
if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
error = -EFAULT;
goto Done;
}
if (rw == WRITE)
bio_set_pages_dirty(bio);
atomic_set(&io_done, 1);
submit_bio(rw | (1 << BIO_RW_SYNC), bio);
while (atomic_read(&io_done))
yield();
Done:
bio_put(bio);
return error;
}
static int bio_read_page(pgoff_t page_off, void *page)
{
return submit(READ, page_off, page);
}
static int bio_write_page(pgoff_t page_off, void *page)
{
return submit(WRITE, page_off, page);
}
/*
* Sanity check if this image makes sense with this kernel/swap context
* I really don't think that it's foolproof but more than nothing..
*/
static const char *sanity_check(void)
{
dump_info();
if (swsusp_info.version_code != LINUX_VERSION_CODE)
return "kernel version";
if (swsusp_info.num_physpages != num_physpages)
return "memory size";
if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
return "system type";
if (strcmp(swsusp_info.uts.release,system_utsname.release))
return "kernel release";
if (strcmp(swsusp_info.uts.version,system_utsname.version))
return "version";
if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
return "machine";
#if 0
/* We can't use number of online CPUs when we use hotplug to remove them ;-))) */
if (swsusp_info.cpus != num_possible_cpus())
return "number of cpus";
#endif
return NULL;
}
static int check_header(void)
{
const char *reason = NULL;
int error;
if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
return error;
/* Is this same machine? */
if ((reason = sanity_check())) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
return -EPERM;
}
nr_copy_pages = swsusp_info.image_pages;
return error;
}
static int check_sig(void)
{
int error;
memset(&swsusp_header, 0, sizeof(swsusp_header));
if ((error = bio_read_page(0, &swsusp_header)))
return error;
if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
memcpy(key_iv, swsusp_header.key_iv, MAXKEY+MAXIV);
memset(swsusp_header.key_iv, 0, MAXKEY+MAXIV);
/*
* Reset swap signature now.
*/
error = bio_write_page(0, &swsusp_header);
} else {
return -EINVAL;
}
if (!error)
pr_debug("swsusp: Signature found, resuming\n");
return error;
}
/**
* data_read - Read image pages from swap.
*
* You do not need to check for overlaps, check_pagedir()
* already did that.
*/
static int data_read(struct pbe *pblist)
{
struct pbe *p;
int error = 0;
int i = 0;
int mod = swsusp_info.image_pages / 100;
void *tfm;
if ((error = crypto_init(0, &tfm)))
return error;
if (!mod)
mod = 1;
printk("swsusp: Reading image data (%lu pages): ",
swsusp_info.image_pages);
for_each_pbe (p, pblist) {
if (!(i % mod))
printk("\b\b\b\b%3d%%", i / mod);
if ((error = crypto_read(p, tfm))) {
crypto_exit(tfm);
return error;
}
i++;
}
printk("\b\b\b\bdone\n");
crypto_exit(tfm);
return error;
}
/**
* read_pagedir - Read page backup list pages from swap
*/
static int read_pagedir(struct pbe *pblist)
{
struct pbe *pbpage, *p;
unsigned int i = 0;
int error;
if (!pblist)
return -EFAULT;
printk("swsusp: Reading pagedir (%lu pages)\n",
swsusp_info.pagedir_pages);
for_each_pb_page (pbpage, pblist) {
unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
error = -EFAULT;
if (offset) {
p = (pbpage + PB_PAGE_SKIP)->next;
error = bio_read_page(offset, (void *)pbpage);
(pbpage + PB_PAGE_SKIP)->next = p;
}
if (error)
break;
}
if (!error)
BUG_ON(i != swsusp_info.pagedir_pages);
return error;
}
static int check_suspend_image(void)
{
int error = 0;
if ((error = check_sig()))
return error;
if ((error = check_header()))
return error;
return 0;
}
static int read_suspend_image(void)
{
int error = 0;
struct pbe *p;
if (!(p = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 0)))
return -ENOMEM;
if ((error = read_pagedir(p)))
return error;
create_pbe_list(p, nr_copy_pages);
mark_unsafe_pages(p);
pagedir_nosave = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
if (pagedir_nosave) {
create_pbe_list(pagedir_nosave, nr_copy_pages);
copy_page_backup_list(pagedir_nosave, p);
}
free_pagedir(p);
if (!pagedir_nosave)
return -ENOMEM;
/* Allocate memory for the image and read the data from swap */
error = alloc_data_pages(pagedir_nosave, GFP_ATOMIC, 1);
if (!error)
error = data_read(pagedir_nosave);
return error;
}
/**
* swsusp_check - Check for saved image in swap
*/
int swsusp_check(void)
{
int error;
resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
if (!IS_ERR(resume_bdev)) {
set_blocksize(resume_bdev, PAGE_SIZE);
error = check_suspend_image();
if (error)
blkdev_put(resume_bdev);
} else
error = PTR_ERR(resume_bdev);
if (!error)
pr_debug("swsusp: resume file found\n");
else
pr_debug("swsusp: Error %d check for resume file\n", error);
return error;
}
/**
* swsusp_read - Read saved image from swap.
*/
int swsusp_read(void)
{
int error;
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return PTR_ERR(resume_bdev);
}
error = read_suspend_image();
blkdev_put(resume_bdev);
memset(key_iv, 0, MAXKEY+MAXIV);
if (!error)
pr_debug("swsusp: Reading resume file was successful\n");
else
pr_debug("swsusp: Error %d resuming\n", error);
return error;
}
/**
* swsusp_close - close swap device.
*/
void swsusp_close(void)
{
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return;
}
blkdev_put(resume_bdev);
}