android_kernel_xiaomi_sm8350/kernel/power/swsusp.c
Rafael J. Wysocki 277c6e2ad7 [PATCH] swsusp: save image header first
This makes the swsusp_info structure become the header of the image in the
literal sense (ie.  it is saved to the swap and read before any other image
data with the help of the swsusp's swap map structure, so generally it is
treated in the same way as the rest of the image).

The main thing it does is to make swsusp_header contain the offset of the swap
map used to track the image data pages rather than the offset of swsusp_info.
 Simultaneously, swsusp_info becomes the first image page written to the swap.

The other changes are generally consequences of the above with a few
exceptions (there's some consolidation in the image reading part as a few
functions turn into trivial wrappers around something else).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:43 -08:00

1043 lines
26 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
*
* 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 MB (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 MB, but if that is impossible, it will
* try to create the smallest image possible.
*/
unsigned int image_size = 500;
#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;
if (!swsusp_resume_device)
return -ENODEV;
spin_lock(&swap_lock);
for (i = 0; i < MAX_SWAPFILES; i++) {
if (!(swap_info[i].flags & SWP_WRITEOK))
continue;
if (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 * 1024 * 1024) / 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_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);
}
/**
* 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);
}