WSL2-Linux-Kernel/kernel/power/swsusp.c

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/*
* 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;
int in_suspend __nosavedata = 0;
#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;
/*
* 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;
}
/**
* swsusp_swap_check - check if the resume device is a swap device
* and get its index (if so)
*/
static int swsusp_swap_check(void) /* This is called before saving image */
{
int res = swap_type_of(swsusp_resume_device);
if (res >= 0) {
root_swap = res;
return 0;
}
return res;
}
/**
* The bitmap is used for tracing allocated swap pages
*
* The entire bitmap consists of a number of bitmap_page
* structures linked with the help of the .next member.
* Thus each page can be allocated individually, so we only
* need to make 0-order memory allocations to create
* the bitmap.
*/
#define BITMAP_PAGE_SIZE (PAGE_SIZE - sizeof(void *))
#define BITMAP_PAGE_CHUNKS (BITMAP_PAGE_SIZE / sizeof(long))
#define BITS_PER_CHUNK (sizeof(long) * 8)
#define BITMAP_PAGE_BITS (BITMAP_PAGE_CHUNKS * BITS_PER_CHUNK)
struct bitmap_page {
unsigned long chunks[BITMAP_PAGE_CHUNKS];
struct bitmap_page *next;
};
/**
* The following functions are used for tracing the allocated
* swap pages, so that they can be freed in case of an error.
*
* The functions operate on a linked bitmap structure defined
* above
*/
static void free_bitmap(struct bitmap_page *bitmap)
{
struct bitmap_page *bp;
while (bitmap) {
bp = bitmap->next;
free_page((unsigned long)bitmap);
bitmap = bp;
}
}
static struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
{
struct bitmap_page *bitmap, *bp;
unsigned int n;
if (!nr_bits)
return NULL;
bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bitmap;
for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bp->next;
if (!bp) {
free_bitmap(bitmap);
return NULL;
}
}
return bitmap;
}
static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
{
unsigned int n;
n = BITMAP_PAGE_BITS;
while (bitmap && n <= bit) {
n += BITMAP_PAGE_BITS;
bitmap = bitmap->next;
}
if (!bitmap)
return -EINVAL;
n -= BITMAP_PAGE_BITS;
bit -= n;
n = 0;
while (bit >= BITS_PER_CHUNK) {
bit -= BITS_PER_CHUNK;
n++;
}
bitmap->chunks[n] |= (1UL << bit);
return 0;
}
static unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
{
unsigned long offset;
offset = swp_offset(get_swap_page_of_type(swap));
if (offset) {
if (bitmap_set(bitmap, offset)) {
swap_free(swp_entry(swap, offset));
offset = 0;
}
}
return offset;
}
static void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
{
unsigned int bit, n;
unsigned long test;
bit = 0;
while (bitmap) {
for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
for (test = 1UL; test; test <<= 1) {
if (bitmap->chunks[n] & test)
swap_free(swp_entry(swap, bit));
bit++;
}
bitmap = bitmap->next;
}
}
/**
* write_page - Write one page to given swap location.
* @buf: Address we're writing.
* @offset: Offset of the swap page we're writing to.
*/
static int write_page(void *buf, unsigned long offset)
{
swp_entry_t entry;
int error = -ENOSPC;
if (offset) {
entry = swp_entry(root_swap, offset);
error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
}
return error;
}
/*
* The swap map is a data structure used for keeping track of each page
* written to a swap partition. It consists of many swap_map_page
* structures that contain each an array of MAP_PAGE_SIZE swap entries.
* These structures are stored on the swap and linked together with the
* help of the .next_swap member.
*
* The swap map is created during suspend. The swap map pages are
* allocated and populated one at a time, so we only need one memory
* page to set up the entire structure.
*
* During resume we also only need to use one swap_map_page structure
* at a time.
*/
#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(long) - 1)
struct swap_map_page {
unsigned long entries[MAP_PAGE_ENTRIES];
unsigned long next_swap;
};
/**
* The swap_map_handle structure is used for handling swap in
* a file-alike way
*/
struct swap_map_handle {
struct swap_map_page *cur;
unsigned long cur_swap;
struct bitmap_page *bitmap;
unsigned int k;
};
static void release_swap_writer(struct swap_map_handle *handle)
{
if (handle->cur)
free_page((unsigned long)handle->cur);
handle->cur = NULL;
if (handle->bitmap)
free_bitmap(handle->bitmap);
handle->bitmap = NULL;
}
static int get_swap_writer(struct swap_map_handle *handle)
{
handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
if (!handle->cur)
return -ENOMEM;
handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
if (!handle->bitmap) {
release_swap_writer(handle);
return -ENOMEM;
}
handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap);
if (!handle->cur_swap) {
release_swap_writer(handle);
return -ENOSPC;
}
handle->k = 0;
return 0;
}
static int swap_write_page(struct swap_map_handle *handle, void *buf)
{
int error;
unsigned long offset;
if (!handle->cur)
return -EINVAL;
offset = alloc_swap_page(root_swap, handle->bitmap);
error = write_page(buf, offset);
if (error)
return error;
handle->cur->entries[handle->k++] = offset;
if (handle->k >= MAP_PAGE_ENTRIES) {
offset = alloc_swap_page(root_swap, handle->bitmap);
if (!offset)
return -ENOSPC;
handle->cur->next_swap = offset;
error = write_page(handle->cur, handle->cur_swap);
if (error)
return error;
memset(handle->cur, 0, PAGE_SIZE);
handle->cur_swap = offset;
handle->k = 0;
}
return 0;
}
static int flush_swap_writer(struct swap_map_handle *handle)
{
if (handle->cur && handle->cur_swap)
return write_page(handle->cur, handle->cur_swap);
else
return -EINVAL;
}
/**
* save_image - save the suspend image data
*/
static int save_image(struct swap_map_handle *handle,
struct snapshot_handle *snapshot,
unsigned int nr_pages)
{
unsigned int m;
int ret;
int error = 0;
printk("Saving image data pages (%u pages) ... ", nr_pages);
m = nr_pages / 100;
if (!m)
m = 1;
nr_pages = 0;
do {
ret = snapshot_read_next(snapshot, PAGE_SIZE);
if (ret > 0) {
error = swap_write_page(handle, data_of(*snapshot));
if (error)
break;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
} while (ret > 0);
if (!error)
printk("\b\b\b\bdone\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 = count_swap_pages(root_swap, 1);
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(void)
{
struct swap_map_handle handle;
struct snapshot_handle snapshot;
struct swsusp_info *header;
unsigned long start;
int error;
if ((error = swsusp_swap_check())) {
printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n");
return error;
}
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_read_next(&snapshot, PAGE_SIZE);
if (error < PAGE_SIZE)
return error < 0 ? error : -EFAULT;
header = (struct swsusp_info *)data_of(snapshot);
if (!enough_swap(header->pages)) {
printk(KERN_ERR "swsusp: Not enough free swap\n");
return -ENOSPC;
}
error = get_swap_writer(&handle);
if (!error) {
start = handle.cur_swap;
error = swap_write_page(&handle, header);
}
if (!error)
error = save_image(&handle, &snapshot, header->pages - 1);
if (!error) {
flush_swap_writer(&handle);
printk("S");
error = mark_swapfiles(swp_entry(root_swap, start));
printk("|\n");
}
if (error)
free_all_swap_pages(root_swap, handle.bitmap);
release_swap_writer(&handle);
return error;
}
/**
* 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;
}
[PATCH] DocBook: changes and extensions to the kernel documentation I have recompiled Linux kernel 2.6.11.5 documentation for me and our university students again. The documentation could be extended for more sources which are equipped by structured comments for recent 2.6 kernels. I have tried to proceed with that task. I have done that more times from 2.6.0 time and it gets boring to do same changes again and again. Linux kernel compiles after changes for i386 and ARM targets. I have added references to some more files into kernel-api book, I have added some section names as well. So please, check that changes do not break something and that categories are not too much skewed. I have changed kernel-doc to accept "fastcall" and "asmlinkage" words reserved by kernel convention. Most of the other changes are modifications in the comments to make kernel-doc happy, accept some parameters description and do not bail out on errors. Changed <pid> to @pid in the description, moved some #ifdef before comments to correct function to comments bindings, etc. You can see result of the modified documentation build at http://cmp.felk.cvut.cz/~pisa/linux/lkdb-2.6.11.tar.gz Some more sources are ready to be included into kernel-doc generated documentation. Sources has been added into kernel-api for now. Some more section names added and probably some more chaos introduced as result of quick cleanup work. Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz> Signed-off-by: Martin Waitz <tali@admingilde.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 19:59:25 +04:00
/*
* 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 void release_swap_reader(struct swap_map_handle *handle)
{
if (handle->cur)
free_page((unsigned long)handle->cur);
handle->cur = NULL;
}
static int get_swap_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_reader(handle);
return error;
}
handle->k = 0;
return 0;
}
static int swap_read_page(struct swap_map_handle *handle, void *buf)
{
unsigned long offset;
int error;
if (!handle->cur)
return -EINVAL;
offset = handle->cur->entries[handle->k];
if (!offset)
return -EFAULT;
error = bio_read_page(offset, buf);
if (error)
return error;
if (++handle->k >= MAP_PAGE_ENTRIES) {
handle->k = 0;
offset = handle->cur->next_swap;
if (!offset)
release_swap_reader(handle);
else
error = bio_read_page(offset, handle->cur);
}
return error;
}
/**
* load_image - load the image using the swap map handle
* @handle and the snapshot handle @snapshot
* (assume there are @nr_pages pages to load)
*/
static int load_image(struct swap_map_handle *handle,
struct snapshot_handle *snapshot,
unsigned int nr_pages)
{
unsigned int m;
int ret;
int error = 0;
printk("Loading image data pages (%u pages) ... ", nr_pages);
m = nr_pages / 100;
if (!m)
m = 1;
nr_pages = 0;
do {
ret = snapshot_write_next(snapshot, PAGE_SIZE);
if (ret > 0) {
error = swap_read_page(handle, data_of(*snapshot));
if (error)
break;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
} while (ret > 0);
if (!error)
printk("\b\b\b\bdone\n");
if (!snapshot_image_loaded(snapshot))
error = -ENODATA;
return error;
}
int swsusp_read(void)
{
int error;
struct swap_map_handle handle;
struct snapshot_handle snapshot;
struct swsusp_info *header;
unsigned int nr_pages;
if (IS_ERR(resume_bdev)) {
pr_debug("swsusp: block device not initialised\n");
return PTR_ERR(resume_bdev);
}
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_write_next(&snapshot, PAGE_SIZE);
if (error < PAGE_SIZE)
return error < 0 ? error : -EFAULT;
header = (struct swsusp_info *)data_of(snapshot);
error = get_swap_reader(&handle, swsusp_header.image);
if (!error)
error = swap_read_page(&handle, header);
if (!error) {
nr_pages = header->image_pages;
error = load_image(&handle, &snapshot, nr_pages);
}
release_swap_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);
}