kernel/power/user.c - linux - Git at Google

 /*
  * 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 <linux/freezer.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;
 	char platform_suspend;
 } 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, NULL) : -1;
 		data->mode = O_RDONLY;
 	} else {
 		data->swap = -1;
 		data->mode = O_WRONLY;
 	}
 	data->bitmap = NULL;
 	data->frozen = 0;
 	data->ready = 0;
 	data->platform_suspend = 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) {
 		mutex_lock(&pm_mutex);
 		thaw_processes();
 		enable_nonboot_cpus();
 		mutex_unlock(&pm_mutex);
 	}
 	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 inline int platform_prepare(void)
 {
 	int error = 0;

 	if (pm_ops && pm_ops->prepare)
 		error = pm_ops->prepare(PM_SUSPEND_DISK);

 	return error;
 }

 static inline void platform_finish(void)
 {
 	if (pm_ops && pm_ops->finish)
 		pm_ops->finish(PM_SUSPEND_DISK);
 }

 static inline int snapshot_suspend(int platform_suspend)
 {
 	int error;

 	mutex_lock(&pm_mutex);
 	/* Free memory before shutting down devices. */
 	error = swsusp_shrink_memory();
 	if (error)
 		goto Finish;

 	if (platform_suspend) {
 		error = platform_prepare();
 		if (error)
 			goto Finish;
 	}
 	suspend_console();
 	error = device_suspend(PMSG_FREEZE);
 	if (error)
 		goto Resume_devices;

 	error = disable_nonboot_cpus();
 	if (!error) {
 		in_suspend = 1;
 		error = swsusp_suspend();
 	}
 	enable_nonboot_cpus();
  Resume_devices:
 	if (platform_suspend)
 		platform_finish();

 	device_resume();
 	resume_console();
  Finish:
 	mutex_unlock(&pm_mutex);
 	return error;
 }

 static inline int snapshot_restore(int platform_suspend)
 {
 	int error;

 	mutex_lock(&pm_mutex);
 	pm_prepare_console();
 	if (platform_suspend) {
 		error = platform_prepare();
 		if (error)
 			goto Finish;
 	}
 	suspend_console();
 	error = device_suspend(PMSG_PRETHAW);
 	if (error)
 		goto Resume_devices;

 	error = disable_nonboot_cpus();
 	if (!error)
 		error = swsusp_resume();

 	enable_nonboot_cpus();
  Resume_devices:
 	if (platform_suspend)
 		platform_finish();

 	device_resume();
 	resume_console();
  Finish:
 	pm_restore_console();
 	mutex_unlock(&pm_mutex);
 	return error;
 }

 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;
 		mutex_lock(&pm_mutex);
 		if (freeze_processes()) {
 			thaw_processes();
 			error = -EBUSY;
 		}
 		mutex_unlock(&pm_mutex);
 		if (!error)
 			data->frozen = 1;
 		break;

 	case SNAPSHOT_UNFREEZE:
 		if (!data->frozen)
 			break;
 		mutex_lock(&pm_mutex);
 		thaw_processes();
 		mutex_unlock(&pm_mutex);
 		data->frozen = 0;
 		break;

 	case SNAPSHOT_ATOMIC_SNAPSHOT:
 		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 			error = -EPERM;
 			break;
 		}
 		error = snapshot_suspend(data->platform_suspend);
 		if (!error)
 			error = put_user(in_suspend, (unsigned int __user *)arg);
 		if (!error)
 			data->ready = 1;
 		break;

 	case SNAPSHOT_ATOMIC_RESTORE:
 		snapshot_write_finalize(&data->handle);
 		if (data->mode != O_WRONLY || !data->frozen ||
 		    !snapshot_image_loaded(&data->handle)) {
 			error = -EPERM;
 			break;
 		}
 		error = snapshot_restore(data->platform_suspend);
 		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, NULL);
 				if (data->swap < 0)
 					error = -ENODEV;
 			} else {
 				data->swap = -1;
 				error = -EINVAL;
 			}
 		} else {
 			error = -EPERM;
 		}
 		break;

 	case SNAPSHOT_S2RAM:
 		if (!pm_ops) {
 			error = -ENOSYS;
 			break;
 		}

 		if (!data->frozen) {
 			error = -EPERM;
 			break;
 		}

 		if (!mutex_trylock(&pm_mutex)) {
 			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 {
 			error = disable_nonboot_cpus();
 			if (!error) {
 				/* Enter S3, system is already frozen */
 				suspend_enter(PM_SUSPEND_MEM);
 				enable_nonboot_cpus();
 			}
 			/* Wake up devices */
 			device_resume();
 		}
 		resume_console();
 		if (pm_ops->finish)
 			pm_ops->finish(PM_SUSPEND_MEM);

  OutS3:
 		mutex_unlock(&pm_mutex);
 		break;

 	case SNAPSHOT_PMOPS:
 		error = -EINVAL;

 		switch (arg) {

 		case PMOPS_PREPARE:
 			if (pm_ops && pm_ops->enter) {
 				data->platform_suspend = 1;
 				error = 0;
 			} else {
 				error = -ENOSYS;
 			}
 			break;

 		case PMOPS_ENTER:
 			if (data->platform_suspend) {
 				kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 				error = pm_ops->enter(PM_SUSPEND_DISK);
 				error = 0;
 			}
 			break;

 		case PMOPS_FINISH:
 			if (data->platform_suspend)
 				error = 0;

 			break;

 		default:
 			printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);

 		}
 		break;

 	case SNAPSHOT_SET_SWAP_AREA:
 		if (data->bitmap) {
 			error = -EPERM;
 		} else {
 			struct resume_swap_area swap_area;
 			dev_t swdev;

 			error = copy_from_user(&swap_area, (void __user *)arg,
 					sizeof(struct resume_swap_area));
 			if (error) {
 				error = -EFAULT;
 				break;
 			}

 			/*
 			 * User space encodes device types as two-byte values,
 			 * so we need to recode them
 			 */
 			swdev = old_decode_dev(swap_area.dev);
 			if (swdev) {
 				offset = swap_area.offset;
 				data->swap = swap_type_of(swdev, offset, NULL);
 				if (data->swap < 0)
 					error = -ENODEV;
 			} else {
 				data->swap = -1;
 				error = -EINVAL;
 			}
 		}
 		break;

 	default:
 		error = -ENOTTY;

 	}

 	return error;
 }

 static const 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);
	/*
	* 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 <linux/freezer.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;
	char platform_suspend;
	} 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, NULL) : -1;
	data->mode = O_RDONLY;
	} else {
	data->swap = -1;
	data->mode = O_WRONLY;
	}
	data->bitmap = NULL;
	data->frozen = 0;
	data->ready = 0;
	data->platform_suspend = 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) {
	mutex_lock(&pm_mutex);
	thaw_processes();
	enable_nonboot_cpus();
	mutex_unlock(&pm_mutex);
	}
	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 inline int platform_prepare(void)
	{
	int error = 0;

	if (pm_ops && pm_ops->prepare)
	error = pm_ops->prepare(PM_SUSPEND_DISK);

	return error;
	}

	static inline void platform_finish(void)
	{
	if (pm_ops && pm_ops->finish)
	pm_ops->finish(PM_SUSPEND_DISK);
	}

	static inline int snapshot_suspend(int platform_suspend)
	{
	int error;

	mutex_lock(&pm_mutex);
	/* Free memory before shutting down devices. */
	error = swsusp_shrink_memory();
	if (error)
	goto Finish;

	if (platform_suspend) {
	error = platform_prepare();
	if (error)
	goto Finish;
	}
	suspend_console();
	error = device_suspend(PMSG_FREEZE);
	if (error)
	goto Resume_devices;

	error = disable_nonboot_cpus();
	if (!error) {
	in_suspend = 1;
	error = swsusp_suspend();
	}
	enable_nonboot_cpus();
	Resume_devices:
	if (platform_suspend)
	platform_finish();

	device_resume();
	resume_console();
	Finish:
	mutex_unlock(&pm_mutex);
	return error;
	}

	static inline int snapshot_restore(int platform_suspend)
	{
	int error;

	mutex_lock(&pm_mutex);
	pm_prepare_console();
	if (platform_suspend) {
	error = platform_prepare();
	if (error)
	goto Finish;
	}
	suspend_console();
	error = device_suspend(PMSG_PRETHAW);
	if (error)
	goto Resume_devices;

	error = disable_nonboot_cpus();
	if (!error)
	error = swsusp_resume();

	enable_nonboot_cpus();
	Resume_devices:
	if (platform_suspend)
	platform_finish();

	device_resume();
	resume_console();
	Finish:
	pm_restore_console();
	mutex_unlock(&pm_mutex);
	return error;
	}

	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;
	mutex_lock(&pm_mutex);
	if (freeze_processes()) {
	thaw_processes();
	error = -EBUSY;
	}
	mutex_unlock(&pm_mutex);
	if (!error)
	data->frozen = 1;
	break;

	case SNAPSHOT_UNFREEZE:
	if (!data->frozen)
	break;
	mutex_lock(&pm_mutex);
	thaw_processes();
	mutex_unlock(&pm_mutex);
	data->frozen = 0;
	break;

	case SNAPSHOT_ATOMIC_SNAPSHOT:
	if (data->mode != O_RDONLY \|\| !data->frozen \|\| data->ready) {
	error = -EPERM;
	break;
	}
	error = snapshot_suspend(data->platform_suspend);
	if (!error)
	error = put_user(in_suspend, (unsigned int __user *)arg);
	if (!error)
	data->ready = 1;
	break;

	case SNAPSHOT_ATOMIC_RESTORE:
	snapshot_write_finalize(&data->handle);
	if (data->mode != O_WRONLY \|\| !data->frozen \|\|
	!snapshot_image_loaded(&data->handle)) {
	error = -EPERM;
	break;
	}
	error = snapshot_restore(data->platform_suspend);
	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, NULL);
	if (data->swap < 0)
	error = -ENODEV;
	} else {
	data->swap = -1;
	error = -EINVAL;
	}
	} else {
	error = -EPERM;
	}
	break;

	case SNAPSHOT_S2RAM:
	if (!pm_ops) {
	error = -ENOSYS;
	break;
	}

	if (!data->frozen) {
	error = -EPERM;
	break;
	}

	if (!mutex_trylock(&pm_mutex)) {
	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 {
	error = disable_nonboot_cpus();
	if (!error) {
	/* Enter S3, system is already frozen */
	suspend_enter(PM_SUSPEND_MEM);
	enable_nonboot_cpus();
	}
	/* Wake up devices */
	device_resume();
	}
	resume_console();
	if (pm_ops->finish)
	pm_ops->finish(PM_SUSPEND_MEM);

	OutS3:
	mutex_unlock(&pm_mutex);
	break;

	case SNAPSHOT_PMOPS:
	error = -EINVAL;

	switch (arg) {

	case PMOPS_PREPARE:
	if (pm_ops && pm_ops->enter) {
	data->platform_suspend = 1;
	error = 0;
	} else {
	error = -ENOSYS;
	}
	break;

	case PMOPS_ENTER:
	if (data->platform_suspend) {
	kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
	error = pm_ops->enter(PM_SUSPEND_DISK);
	error = 0;
	}
	break;

	case PMOPS_FINISH:
	if (data->platform_suspend)
	error = 0;

	break;

	default:
	printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);

	}
	break;

	case SNAPSHOT_SET_SWAP_AREA:
	if (data->bitmap) {
	error = -EPERM;
	} else {
	struct resume_swap_area swap_area;
	dev_t swdev;

	error = copy_from_user(&swap_area, (void __user *)arg,
	sizeof(struct resume_swap_area));
	if (error) {
	error = -EFAULT;
	break;
	}

	/*
	* User space encodes device types as two-byte values,
	* so we need to recode them
	*/
	swdev = old_decode_dev(swap_area.dev);
	if (swdev) {
	offset = swap_area.offset;
	data->swap = swap_type_of(swdev, offset, NULL);
	if (data->swap < 0)
	error = -ENODEV;
	} else {
	data->swap = -1;
	error = -EINVAL;
	}
	}
	break;

	default:
	error = -ENOTTY;

	}

	return error;
	}

	static const 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);