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3aef83e0ef
linux/kernel/power/user.c
Rafael J. Wysocki 3aef83e0ef [PATCH] swsusp: use block device offsets to identify swap locations 
Make swsusp use block device offsets instead of swap offsets to identify swap
locations and make it use the same code paths for writing as well as for
reading data.

This allows us to use the same code for handling swap files and swap
partitions and to simplify the code, eg.  by dropping rw_swap_page_sync().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:27 -08:00

375 lines
7.5 KiB
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/*
* linux/kernel/power/user.c
*
* This file provides the user space interface for software suspend/resume.
*
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*
*/
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <asm/uaccess.h>
#include "power.h"
#define SNAPSHOT_MINOR 231
static struct snapshot_data {
struct snapshot_handle handle;
int swap;
struct bitmap_page *bitmap;
int mode;
char frozen;
char ready;
} snapshot_state;
static atomic_t device_available = ATOMIC_INIT(1);
static int snapshot_open(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
if (!atomic_add_unless(&device_available, -1, 0))
return -EBUSY;
if ((filp->f_flags & O_ACCMODE) == O_RDWR)
return -ENOSYS;
nonseekable_open(inode, filp);
data = &snapshot_state;
filp->private_data = data;
memset(&data->handle, 0, sizeof(struct snapshot_handle));
if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
data->swap = swsusp_resume_device ?
swap_type_of(swsusp_resume_device, 0) : -1;
data->mode = O_RDONLY;
} else {
data->swap = -1;
data->mode = O_WRONLY;
}
data->bitmap = NULL;
data->frozen = 0;
data->ready = 0;
return 0;
}
static int snapshot_release(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
swsusp_free();
data = filp->private_data;
free_all_swap_pages(data->swap, data->bitmap);
free_bitmap(data->bitmap);
if (data->frozen) {
down(&pm_sem);
thaw_processes();
enable_nonboot_cpus();
up(&pm_sem);
}
atomic_inc(&device_available);
return 0;
}
static ssize_t snapshot_read(struct file *filp, char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
data = filp->private_data;
res = snapshot_read_next(&data->handle, count);
if (res > 0) {
if (copy_to_user(buf, data_of(data->handle), res))
res = -EFAULT;
else
*offp = data->handle.offset;
}
return res;
}
static ssize_t snapshot_write(struct file *filp, const char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
data = filp->private_data;
res = snapshot_write_next(&data->handle, count);
if (res > 0) {
if (copy_from_user(data_of(data->handle), buf, res))
res = -EFAULT;
else
*offp = data->handle.offset;
}
return res;
}
static int snapshot_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
int error = 0;
struct snapshot_data *data;
loff_t avail;
sector_t offset;
if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
return -ENOTTY;
if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
return -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
data = filp->private_data;
switch (cmd) {
case SNAPSHOT_FREEZE:
if (data->frozen)
break;
down(&pm_sem);
error = disable_nonboot_cpus();
if (!error) {
error = freeze_processes();
if (error) {
thaw_processes();
enable_nonboot_cpus();
error = -EBUSY;
}
}
up(&pm_sem);
if (!error)
data->frozen = 1;
break;
case SNAPSHOT_UNFREEZE:
if (!data->frozen)
break;
down(&pm_sem);
thaw_processes();
enable_nonboot_cpus();
up(&pm_sem);
data->frozen = 0;
break;
case SNAPSHOT_ATOMIC_SNAPSHOT:
if (data->mode != O_RDONLY || !data->frozen || data->ready) {
error = -EPERM;
break;
}
down(&pm_sem);
/* Free memory before shutting down devices. */
error = swsusp_shrink_memory();
if (!error) {
suspend_console();
error = device_suspend(PMSG_FREEZE);
if (!error) {
in_suspend = 1;
error = swsusp_suspend();
device_resume();
}
resume_console();
}
up(&pm_sem);
if (!error)
error = put_user(in_suspend, (unsigned int __user *)arg);
if (!error)
data->ready = 1;
break;
case SNAPSHOT_ATOMIC_RESTORE:
if (data->mode != O_WRONLY || !data->frozen ||
!snapshot_image_loaded(&data->handle)) {
error = -EPERM;
break;
}
snapshot_free_unused_memory(&data->handle);
down(&pm_sem);
pm_prepare_console();
suspend_console();
error = device_suspend(PMSG_PRETHAW);
if (!error) {
error = swsusp_resume();
device_resume();
}
resume_console();
pm_restore_console();
up(&pm_sem);
break;
case SNAPSHOT_FREE:
swsusp_free();
memset(&data->handle, 0, sizeof(struct snapshot_handle));
data->ready = 0;
break;
case SNAPSHOT_SET_IMAGE_SIZE:
image_size = arg;
break;
case SNAPSHOT_AVAIL_SWAP:
avail = count_swap_pages(data->swap, 1);
avail <<= PAGE_SHIFT;
error = put_user(avail, (loff_t __user *)arg);
break;
case SNAPSHOT_GET_SWAP_PAGE:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
if (!data->bitmap) {
data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
if (!data->bitmap) {
error = -ENOMEM;
break;
}
}
offset = alloc_swapdev_block(data->swap, data->bitmap);
if (offset) {
offset <<= PAGE_SHIFT;
error = put_user(offset, (sector_t __user *)arg);
} else {
error = -ENOSPC;
}
break;
case SNAPSHOT_FREE_SWAP_PAGES:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
free_all_swap_pages(data->swap, data->bitmap);
free_bitmap(data->bitmap);
data->bitmap = NULL;
break;
case SNAPSHOT_SET_SWAP_FILE:
if (!data->bitmap) {
/*
* User space encodes device types as two-byte values,
* so we need to recode them
*/
if (old_decode_dev(arg)) {
data->swap = swap_type_of(old_decode_dev(arg), 0);
if (data->swap < 0)
error = -ENODEV;
} else {
data->swap = -1;
error = -EINVAL;
}
} else {
error = -EPERM;
}
break;
case SNAPSHOT_S2RAM:
if (!data->frozen) {
error = -EPERM;
break;
}
if (down_trylock(&pm_sem)) {
error = -EBUSY;
break;
}
if (pm_ops->prepare) {
error = pm_ops->prepare(PM_SUSPEND_MEM);
if (error)
goto OutS3;
}
/* Put devices to sleep */
suspend_console();
error = device_suspend(PMSG_SUSPEND);
if (error) {
printk(KERN_ERR "Failed to suspend some devices.\n");
} else {
/* Enter S3, system is already frozen */
suspend_enter(PM_SUSPEND_MEM);
/* Wake up devices */
device_resume();
}
resume_console();
if (pm_ops->finish)
pm_ops->finish(PM_SUSPEND_MEM);
OutS3:
up(&pm_sem);
break;
case SNAPSHOT_PMOPS:
switch (arg) {
case PMOPS_PREPARE:
if (pm_ops->prepare) {
error = pm_ops->prepare(PM_SUSPEND_DISK);
}
break;
case PMOPS_ENTER:
kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
error = pm_ops->enter(PM_SUSPEND_DISK);
break;
case PMOPS_FINISH:
if (pm_ops && pm_ops->finish) {
pm_ops->finish(PM_SUSPEND_DISK);
}
break;
default:
printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
error = -EINVAL;
}
break;
default:
error = -ENOTTY;
}
return error;
}
static struct file_operations snapshot_fops = {
.open = snapshot_open,
.release = snapshot_release,
.read = snapshot_read,
.write = snapshot_write,
.llseek = no_llseek,
.ioctl = snapshot_ioctl,
};
static struct miscdevice snapshot_device = {
.minor = SNAPSHOT_MINOR,
.name = "snapshot",
.fops = &snapshot_fops,
};
static int __init snapshot_device_init(void)
{
return misc_register(&snapshot_device);
};
device_initcall(snapshot_device_init);
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