https://github.com/torvalds/linux
Tip revision: 535744878e34d01a53f946f26dfbca37186f2cf8 authored by Linus Torvalds on 11 March 2006, 22:12:55 UTC
Linux 2.6.16-rc6
Linux 2.6.16-rc6
Tip revision: 5357448
swsusp.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
*
* Rafael J. Wysocki <rjw@sisk.pl>
* Added the swap map data structure and reworked the handling of swap
*
* 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 "power.h"
/*
* Preferred image size in bytes (tunable via /sys/power/image_size).
* When it is set to N, swsusp will do its best to ensure the image
* size will not exceed N bytes, but if that is impossible, it will
* try to create the smallest image possible.
*/
unsigned long image_size = 500 * 1024 * 1024;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void);
int save_highmem(void);
int restore_highmem(void);
#else
static int save_highmem(void) { return 0; }
static int restore_highmem(void) { return 0; }
static unsigned int count_highmem_pages(void) { return 0; }
#endif
extern char resume_file[];
#define SWSUSP_SIG "S1SUSPEND"
static struct swsusp_header {
char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
swp_entry_t image;
char orig_sig[10];
char sig[10];
} __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
static struct swsusp_info swsusp_info;
/*
* Saving part...
*/
static unsigned short root_swap = 0xffff;
static int mark_swapfiles(swp_entry_t start)
{
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);
swsusp_header.image = start;
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 inline 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;
spin_lock(&swap_lock);
for (i = 0; i < MAX_SWAPFILES; i++) {
if (!(swap_info[i].flags & SWP_WRITEOK))
continue;
if (!swsusp_resume_device || is_resume_device(swap_info + i)) {
spin_unlock(&swap_lock);
root_swap = i;
return 0;
}
}
spin_unlock(&swap_lock);
return -ENODEV;
}
/**
* 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 = -ENOSPC;
entry = get_swap_page_of_type(root_swap);
if (swp_offset(entry)) {
error = rw_swap_page_sync(WRITE, entry, virt_to_page(addr));
if (!error || error == -EIO)
*loc = entry;
}
return error;
}
/**
* Swap map-handling functions
*
* The swap map is a data structure used for keeping track of each page
* written to the swap. It consists of many swap_map_page structures
* that contain each an array of MAP_PAGE_SIZE swap entries.
* These structures are linked together with the help of either the
* .next (in memory) or the .next_swap (in swap) member.
*
* The swap map is created during suspend. At that time we need to keep
* it in memory, because we have to free all of the allocated swap
* entries if an error occurs. The memory needed is preallocated
* so that we know in advance if there's enough of it.
*
* The first swap_map_page structure is filled with the swap entries that
* correspond to the first MAP_PAGE_SIZE data pages written to swap and
* so on. After the all of the data pages have been written, the order
* of the swap_map_page structures in the map is reversed so that they
* can be read from swap in the original order. This causes the data
* pages to be loaded in exactly the same order in which they have been
* saved.
*
* During resume we only need to use one swap_map_page structure
* at a time, which means that we only need to use two memory pages for
* reading the image - one for reading the swap_map_page structures
* and the second for reading the data pages from swap.
*/
#define MAP_PAGE_SIZE ((PAGE_SIZE - sizeof(swp_entry_t) - sizeof(void *)) \
/ sizeof(swp_entry_t))
struct swap_map_page {
swp_entry_t entries[MAP_PAGE_SIZE];
swp_entry_t next_swap;
struct swap_map_page *next;
};
static inline void free_swap_map(struct swap_map_page *swap_map)
{
struct swap_map_page *swp;
while (swap_map) {
swp = swap_map->next;
free_page((unsigned long)swap_map);
swap_map = swp;
}
}
static struct swap_map_page *alloc_swap_map(unsigned int nr_pages)
{
struct swap_map_page *swap_map, *swp;
unsigned n = 0;
if (!nr_pages)
return NULL;
pr_debug("alloc_swap_map(): nr_pages = %d\n", nr_pages);
swap_map = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
swp = swap_map;
for (n = MAP_PAGE_SIZE; n < nr_pages; n += MAP_PAGE_SIZE) {
swp->next = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
swp = swp->next;
if (!swp) {
free_swap_map(swap_map);
return NULL;
}
}
return swap_map;
}
/**
* reverse_swap_map - reverse the order of pages in the swap map
* @swap_map
*/
static inline struct swap_map_page *reverse_swap_map(struct swap_map_page *swap_map)
{
struct swap_map_page *prev, *next;
prev = NULL;
while (swap_map) {
next = swap_map->next;
swap_map->next = prev;
prev = swap_map;
swap_map = next;
}
return prev;
}
/**
* free_swap_map_entries - free the swap entries allocated to store
* the swap map @swap_map (this is only called in case of an error)
*/
static inline void free_swap_map_entries(struct swap_map_page *swap_map)
{
while (swap_map) {
if (swap_map->next_swap.val)
swap_free(swap_map->next_swap);
swap_map = swap_map->next;
}
}
/**
* save_swap_map - save the swap map used for tracing the data pages
* stored in the swap
*/
static int save_swap_map(struct swap_map_page *swap_map, swp_entry_t *start)
{
swp_entry_t entry = (swp_entry_t){0};
int error;
while (swap_map) {
swap_map->next_swap = entry;
if ((error = write_page((unsigned long)swap_map, &entry)))
return error;
swap_map = swap_map->next;
}
*start = entry;
return 0;
}
/**
* free_image_entries - free the swap entries allocated to store
* the image data pages (this is only called in case of an error)
*/
static inline void free_image_entries(struct swap_map_page *swp)
{
unsigned k;
while (swp) {
for (k = 0; k < MAP_PAGE_SIZE; k++)
if (swp->entries[k].val)
swap_free(swp->entries[k]);
swp = swp->next;
}
}
/**
* The swap_map_handle structure is used for handling the swap map in
* a file-alike way
*/
struct swap_map_handle {
struct swap_map_page *cur;
unsigned int k;
};
static inline void init_swap_map_handle(struct swap_map_handle *handle,
struct swap_map_page *map)
{
handle->cur = map;
handle->k = 0;
}
static inline int swap_map_write_page(struct swap_map_handle *handle,
unsigned long addr)
{
int error;
error = write_page(addr, handle->cur->entries + handle->k);
if (error)
return error;
if (++handle->k >= MAP_PAGE_SIZE) {
handle->cur = handle->cur->next;
handle->k = 0;
}
return 0;
}
/**
* save_image_data - save the data pages pointed to by the PBEs
* from the list @pblist using the swap map handle @handle
* (assume there are @nr_pages data pages to save)
*/
static int save_image_data(struct pbe *pblist,
struct swap_map_handle *handle,
unsigned int nr_pages)
{
unsigned int m;
struct pbe *p;
int error = 0;
printk("Saving image data pages (%u pages) ... ", nr_pages);
m = nr_pages / 100;
if (!m)
m = 1;
nr_pages = 0;
for_each_pbe (p, pblist) {
error = swap_map_write_page(handle, p->address);
if (error)
break;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
if (!error)
printk("\b\b\b\bdone\n");
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: Total: %ld Pages\n", swsusp_info.pages);
}
static void init_header(unsigned int nr_pages)
{
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.cpus = num_online_cpus();
swsusp_info.image_pages = nr_pages;
swsusp_info.pages = nr_pages +
((nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
}
/**
* pack_orig_addresses - the .orig_address fields of the PBEs from the
* list starting at @pbe are stored in the array @buf[] (1 page)
*/
static inline struct pbe *pack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
buf[j] = pbe->orig_address;
pbe = pbe->next;
}
if (!pbe)
for (; j < PAGE_SIZE / sizeof(long); j++)
buf[j] = 0;
return pbe;
}
/**
* save_image_metadata - save the .orig_address fields of the PBEs
* from the list @pblist using the swap map handle @handle
*/
static int save_image_metadata(struct pbe *pblist,
struct swap_map_handle *handle)
{
unsigned long *buf;
unsigned int n = 0;
struct pbe *p;
int error = 0;
printk("Saving image metadata ... ");
buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
if (!buf)
return -ENOMEM;
p = pblist;
while (p) {
p = pack_orig_addresses(buf, p);
error = swap_map_write_page(handle, (unsigned long)buf);
if (error)
break;
n++;
}
free_page((unsigned long)buf);
if (!error)
printk("done (%u pages saved)\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 from the resume partition.
*/
static int enough_swap(unsigned int nr_pages)
{
unsigned int free_swap = swap_info[root_swap].pages -
swap_info[root_swap].inuse_pages;
pr_debug("swsusp: free swap pages: %u\n", free_swap);
return free_swap > (nr_pages + PAGES_FOR_IO +
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
/**
* swsusp_write - Write entire image and metadata.
*
* 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(struct pbe *pblist, unsigned int nr_pages)
{
struct swap_map_page *swap_map;
struct swap_map_handle handle;
swp_entry_t start;
int error;
if ((error = swsusp_swap_check())) {
printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n");
return error;
}
if (!enough_swap(nr_pages)) {
printk(KERN_ERR "swsusp: Not enough free swap\n");
return -ENOSPC;
}
init_header(nr_pages);
swap_map = alloc_swap_map(swsusp_info.pages);
if (!swap_map)
return -ENOMEM;
init_swap_map_handle(&handle, swap_map);
error = swap_map_write_page(&handle, (unsigned long)&swsusp_info);
if (!error)
error = save_image_metadata(pblist, &handle);
if (!error)
error = save_image_data(pblist, &handle, nr_pages);
if (error)
goto Free_image_entries;
swap_map = reverse_swap_map(swap_map);
error = save_swap_map(swap_map, &start);
if (error)
goto Free_map_entries;
dump_info();
printk( "S" );
error = mark_swapfiles(start);
printk( "|\n" );
if (error)
goto Free_map_entries;
Free_swap_map:
free_swap_map(swap_map);
return error;
Free_map_entries:
free_swap_map_entries(swap_map);
Free_image_entries:
free_image_entries(swap_map);
goto Free_swap_map;
}
/**
* swsusp_shrink_memory - Try to free as much memory as needed
*
* ... but do not OOM-kill anyone
*
* Notice: all userland should be stopped before it is called, or
* livelock is possible.
*/
#define SHRINK_BITE 10000
int swsusp_shrink_memory(void)
{
long size, tmp;
struct zone *zone;
unsigned long pages = 0;
unsigned int i = 0;
char *p = "-\\|/";
printk("Shrinking memory... ");
do {
size = 2 * count_highmem_pages();
size += size / 50 + count_data_pages();
size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
PAGES_FOR_IO;
tmp = size;
for_each_zone (zone)
if (!is_highmem(zone))
tmp -= zone->free_pages;
if (tmp > 0) {
tmp = shrink_all_memory(SHRINK_BITE);
if (!tmp)
return -ENOMEM;
pages += tmp;
} else if (size > image_size / PAGE_SIZE) {
tmp = shrink_all_memory(SHRINK_BITE);
pages += tmp;
}
printk("\b%c", p[i++%4]);
} while (tmp > 0);
printk("\bdone (%lu pages freed)\n", pages);
return 0;
}
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 = 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->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;
}
atomic_set(&io_done, 1);
submit_bio(rw | (1 << BIO_RW_SYNC), bio);
while (atomic_read(&io_done))
yield();
if (rw == READ)
bio_set_pages_dirty(bio);
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);
}
/**
* The following functions allow us to read data using a swap map
* in a file-alike way
*/
static inline void release_swap_map_reader(struct swap_map_handle *handle)
{
if (handle->cur)
free_page((unsigned long)handle->cur);
handle->cur = NULL;
}
static inline int get_swap_map_reader(struct swap_map_handle *handle,
swp_entry_t start)
{
int error;
if (!swp_offset(start))
return -EINVAL;
handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
if (!handle->cur)
return -ENOMEM;
error = bio_read_page(swp_offset(start), handle->cur);
if (error) {
release_swap_map_reader(handle);
return error;
}
handle->k = 0;
return 0;
}
static inline int swap_map_read_page(struct swap_map_handle *handle, void *buf)
{
unsigned long offset;
int error;
if (!handle->cur)
return -EINVAL;
offset = swp_offset(handle->cur->entries[handle->k]);
if (!offset)
return -EINVAL;
error = bio_read_page(offset, buf);
if (error)
return error;
if (++handle->k >= MAP_PAGE_SIZE) {
handle->k = 0;
offset = swp_offset(handle->cur->next_swap);
if (!offset)
release_swap_map_reader(handle);
else
error = bio_read_page(offset, handle->cur);
}
return error;
}
static int check_header(void)
{
char *reason = NULL;
dump_info();
if (swsusp_info.version_code != LINUX_VERSION_CODE)
reason = "kernel version";
if (swsusp_info.num_physpages != num_physpages)
reason = "memory size";
if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
reason = "system type";
if (strcmp(swsusp_info.uts.release,system_utsname.release))
reason = "kernel release";
if (strcmp(swsusp_info.uts.version,system_utsname.version))
reason = "version";
if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
reason = "machine";
if (reason) {
printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
return -EPERM;
}
return 0;
}
/**
* load_image_data - load the image data using the swap map handle
* @handle and store them using the page backup list @pblist
* (assume there are @nr_pages pages to load)
*/
static int load_image_data(struct pbe *pblist,
struct swap_map_handle *handle,
unsigned int nr_pages)
{
int error;
unsigned int m;
struct pbe *p;
if (!pblist)
return -EINVAL;
printk("Loading image data pages (%u pages) ... ", nr_pages);
m = nr_pages / 100;
if (!m)
m = 1;
nr_pages = 0;
p = pblist;
while (p) {
error = swap_map_read_page(handle, (void *)p->address);
if (error)
break;
p = p->next;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
if (!error)
printk("\b\b\b\bdone\n");
return error;
}
/**
* unpack_orig_addresses - copy the elements of @buf[] (1 page) to
* the PBEs in the list starting at @pbe
*/
static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
struct pbe *pbe)
{
int j;
for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
pbe->orig_address = buf[j];
pbe = pbe->next;
}
return pbe;
}
/**
* load_image_metadata - load the image metadata using the swap map
* handle @handle and put them into the PBEs in the list @pblist
*/
static int load_image_metadata(struct pbe *pblist, struct swap_map_handle *handle)
{
struct pbe *p;
unsigned long *buf;
unsigned int n = 0;
int error = 0;
printk("Loading image metadata ... ");
buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
if (!buf)
return -ENOMEM;
p = pblist;
while (p) {
error = swap_map_read_page(handle, buf);
if (error)
break;
p = unpack_orig_addresses(buf, p);
n++;
}
free_page((unsigned long)buf);
if (!error)
printk("done (%u pages loaded)\n", n);
return error;
}
int swsusp_read(struct pbe **pblist_ptr)
{
int error;
struct pbe *p, *pblist;
struct swap_map_handle handle;
unsigned int nr_pages;
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return PTR_ERR(resume_bdev);
}
error = get_swap_map_reader(&handle, swsusp_header.image);
if (!error)
error = swap_map_read_page(&handle, &swsusp_info);
if (!error)
error = check_header();
if (error)
return error;
nr_pages = swsusp_info.image_pages;
p = alloc_pagedir(nr_pages, GFP_ATOMIC, 0);
if (!p)
return -ENOMEM;
error = load_image_metadata(p, &handle);
if (!error) {
mark_unsafe_pages(p);
pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p);
if (!pblist)
error = -ENOMEM;
/* Allocate memory for the image and read the data from swap */
if (!error)
error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
if (!error) {
release_eaten_pages();
error = load_image_data(pblist, &handle, nr_pages);
}
if (!error)
*pblist_ptr = pblist;
}
release_swap_map_reader(&handle);
blkdev_put(resume_bdev);
if (!error)
pr_debug("swsusp: Reading resume file was successful\n");
else
pr_debug("swsusp: Error %d resuming\n", error);
return error;
}
/**
* swsusp_check - Check for swsusp signature in the resume device
*/
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);
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);
/* Reset swap signature now */
error = bio_write_page(0, &swsusp_header);
} else {
return -EINVAL;
}
if (error)
blkdev_put(resume_bdev);
else
pr_debug("swsusp: Signature found, resuming\n");
} else {
error = PTR_ERR(resume_bdev);
}
if (error)
pr_debug("swsusp: Error %d check for resume file\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);
}