[linux.git] / kernel / power / user.c

/*
 * linux/kernel/power/user.c
 *
 * This file provides the user space interface for software suspend/resume.
 *
 * Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
 *
 * 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/compat.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;
	int mode;
	bool frozen;
	bool ready;
	bool platform_support;
	bool free_bitmaps;
} snapshot_state;

atomic_t snapshot_device_available = ATOMIC_INIT(1);

static int snapshot_open(struct inode *inode, struct file *filp)
{
	struct snapshot_data *data;
	int error;

	if (!hibernation_available())
		return -EPERM;

	lock_system_sleep();

	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		goto Unlock;
	}

	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
		atomic_inc(&snapshot_device_available);
		error = -ENOSYS;
		goto Unlock;
	}
	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) {
		/* Hibernating.  The image device should be accessible. */
		data->swap = swsusp_resume_device ?
			swap_type_of(swsusp_resume_device, 0, NULL) : -1;
		data->mode = O_RDONLY;
		data->free_bitmaps = false;
		error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
		if (error)
			pm_notifier_call_chain(PM_POST_HIBERNATION);
	} else {
		/*
		 * Resuming.  We may need to wait for the image device to
		 * appear.
		 */
		wait_for_device_probe();

		data->swap = -1;
		data->mode = O_WRONLY;
		error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
		if (!error) {
			error = create_basic_memory_bitmaps();
			data->free_bitmaps = !error;
		}
		if (error)
			pm_notifier_call_chain(PM_POST_RESTORE);
	}
	if (error)
		atomic_inc(&snapshot_device_available);

	data->frozen = false;
	data->ready = false;
	data->platform_support = false;

 Unlock:
	unlock_system_sleep();

	return error;
}

static int snapshot_release(struct inode *inode, struct file *filp)
{
	struct snapshot_data *data;

	lock_system_sleep();

	swsusp_free();
	data = filp->private_data;
	free_all_swap_pages(data->swap);
	if (data->frozen) {
		pm_restore_gfp_mask();
		free_basic_memory_bitmaps();
		thaw_processes();
	} else if (data->free_bitmaps) {
		free_basic_memory_bitmaps();
	}
	pm_notifier_call_chain(data->mode == O_RDONLY ?
			PM_POST_HIBERNATION : PM_POST_RESTORE);
	atomic_inc(&snapshot_device_available);

	unlock_system_sleep();

	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;
	loff_t pg_offp = *offp & ~PAGE_MASK;

	lock_system_sleep();

	data = filp->private_data;
	if (!data->ready) {
		res = -ENODATA;
		goto Unlock;
	}
	if (!pg_offp) { /* on page boundary? */
		res = snapshot_read_next(&data->handle);
		if (res <= 0)
			goto Unlock;
	} else {
		res = PAGE_SIZE - pg_offp;
	}

	res = simple_read_from_buffer(buf, count, &pg_offp,
			data_of(data->handle), res);
	if (res > 0)
		*offp += res;

 Unlock:
	unlock_system_sleep();

	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;
	loff_t pg_offp = *offp & ~PAGE_MASK;

	lock_system_sleep();

	data = filp->private_data;

	if (!pg_offp) {
		res = snapshot_write_next(&data->handle);
		if (res <= 0)
			goto unlock;
	} else {
		res = PAGE_SIZE - pg_offp;
	}

	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
			buf, count);
	if (res > 0)
		*offp += res;
unlock:
	unlock_system_sleep();

	return res;
}

static long snapshot_ioctl(struct file *filp, unsigned int cmd,
							unsigned long arg)
{
	int error = 0;
	struct snapshot_data *data;
	loff_t size;
	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;

	if (!mutex_trylock(&pm_mutex))
		return -EBUSY;

	lock_device_hotplug();
	data = filp->private_data;

	switch (cmd) {

	case SNAPSHOT_FREEZE:
		if (data->frozen)
			break;

		printk("Syncing filesystems ... ");
		sys_sync();
		printk("done.\n");

		error = freeze_processes();
		if (error)
			break;

		error = create_basic_memory_bitmaps();
		if (error)
			thaw_processes();
		else
			data->frozen = true;

		break;

	case SNAPSHOT_UNFREEZE:
		if (!data->frozen || data->ready)
			break;
		pm_restore_gfp_mask();
		free_basic_memory_bitmaps();
		data->free_bitmaps = false;
		thaw_processes();
		data->frozen = false;
		break;

	case SNAPSHOT_CREATE_IMAGE:
		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
			error = -EPERM;
			break;
		}
		pm_restore_gfp_mask();
		error = hibernation_snapshot(data->platform_support);
		if (!error) {
			error = put_user(in_suspend, (int __user *)arg);
			data->ready = !freezer_test_done && !error;
			freezer_test_done = false;
		}
		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 = hibernation_restore(data->platform_support);
		break;

	case SNAPSHOT_FREE:
		swsusp_free();
		memset(&data->handle, 0, sizeof(struct snapshot_handle));
		data->ready = false;
		/*
		 * It is necessary to thaw kernel threads here, because
		 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
		 * SNAPSHOT_FREE.  In that case, if kernel threads were not
		 * thawed, the preallocation of memory carried out by
		 * hibernation_snapshot() might run into problems (i.e. it
		 * might fail or even deadlock).
		 */
		thaw_kernel_threads();
		break;

	case SNAPSHOT_PREF_IMAGE_SIZE:
		image_size = arg;
		break;

	case SNAPSHOT_GET_IMAGE_SIZE:
		if (!data->ready) {
			error = -ENODATA;
			break;
		}
		size = snapshot_get_image_size();
		size <<= PAGE_SHIFT;
		error = put_user(size, (loff_t __user *)arg);
		break;

	case SNAPSHOT_AVAIL_SWAP_SIZE:
		size = count_swap_pages(data->swap, 1);
		size <<= PAGE_SHIFT;
		error = put_user(size, (loff_t __user *)arg);
		break;

	case SNAPSHOT_ALLOC_SWAP_PAGE:
		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
			error = -ENODEV;
			break;
		}
		offset = alloc_swapdev_block(data->swap);
		if (offset) {
			offset <<= PAGE_SHIFT;
			error = put_user(offset, (loff_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);
		break;

	case SNAPSHOT_S2RAM:
		if (!data->frozen) {
			error = -EPERM;
			break;
		}
		/*
		 * Tasks are frozen and the notifiers have been called with
		 * PM_HIBERNATION_PREPARE
		 */
		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
		data->ready = false;
		break;

	case SNAPSHOT_PLATFORM_SUPPORT:
		data->platform_support = !!arg;
		break;

	case SNAPSHOT_POWER_OFF:
		if (data->platform_support)
			error = hibernation_platform_enter();
		break;

	case SNAPSHOT_SET_SWAP_AREA:
		if (swsusp_swap_in_use()) {
			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 = new_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;

	}

	unlock_device_hotplug();
	mutex_unlock(&pm_mutex);

	return error;
}

#ifdef CONFIG_COMPAT

struct compat_resume_swap_area {
	compat_loff_t offset;
	u32 dev;
} __packed;

static long
snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));

	switch (cmd) {
	case SNAPSHOT_GET_IMAGE_SIZE:
	case SNAPSHOT_AVAIL_SWAP_SIZE:
	case SNAPSHOT_ALLOC_SWAP_PAGE: {
		compat_loff_t __user *uoffset = compat_ptr(arg);
		loff_t offset;
		mm_segment_t old_fs;
		int err;

		old_fs = get_fs();
		set_fs(KERNEL_DS);
		err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
		set_fs(old_fs);
		if (!err && put_user(offset, uoffset))
			err = -EFAULT;
		return err;
	}

	case SNAPSHOT_CREATE_IMAGE:
		return snapshot_ioctl(file, cmd,
				      (unsigned long) compat_ptr(arg));

	case SNAPSHOT_SET_SWAP_AREA: {
		struct compat_resume_swap_area __user *u_swap_area =
			compat_ptr(arg);
		struct resume_swap_area swap_area;
		mm_segment_t old_fs;
		int err;

		err = get_user(swap_area.offset, &u_swap_area->offset);
		err |= get_user(swap_area.dev, &u_swap_area->dev);
		if (err)
			return -EFAULT;
		old_fs = get_fs();
		set_fs(KERNEL_DS);
		err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
				     (unsigned long) &swap_area);
		set_fs(old_fs);
		return err;
	}

	default:
		return snapshot_ioctl(file, cmd, arg);
	}
}

#endif /* CONFIG_COMPAT */

static const struct file_operations snapshot_fops = {
	.open = snapshot_open,
	.release = snapshot_release,
	.read = snapshot_read,
	.write = snapshot_write,
	.llseek = no_llseek,
	.unlocked_ioctl = snapshot_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = snapshot_compat_ioctl,
#endif
};

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);
Commit	Line	Data
6e1819d6 RW	1	/*
	2	* linux/kernel/power/user.c
	3	*
	4	* This file provides the user space interface for software suspend/resume.
	5	*
	6	* Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
	7	*
	8	* This file is released under the GPLv2.
	9	*
	10	*/
	11
	12	#include <linux/suspend.h>
	13	#include <linux/syscalls.h>
3592695c	14	#include <linux/reboot.h>
6e1819d6 RW	15	#include <linux/string.h>
	16	#include <linux/device.h>
	17	#include <linux/miscdevice.h>
	18	#include <linux/mm.h>
	19	#include <linux/swap.h>
	20	#include <linux/swapops.h>
	21	#include <linux/pm.h>
	22	#include <linux/fs.h>
c336078b	23	#include <linux/compat.h>
97c7801c	24	#include <linux/console.h>
e3920fb4	25	#include <linux/cpu.h>
7dfb7103	26	#include <linux/freezer.h>
6e1819d6 RW	27
	28	#include <asm/uaccess.h>
	29
	30	#include "power.h"
	31
eb57c1cf	32
6e1819d6 RW	33	#define SNAPSHOT_MINOR 231
	34
	35	static struct snapshot_data {
	36	struct snapshot_handle handle;
	37	int swap;
6e1819d6	38	int mode;
7bc9b1cf RW	39	bool frozen;
	40	bool ready;
	41	bool platform_support;
aab17289	42	bool free_bitmaps;
6e1819d6 RW	43	} snapshot_state;
6e1819d6 RW	44
0709db60	45	atomic_t snapshot_device_available = ATOMIC_INIT(1);
6e1819d6 RW	46
	47	static int snapshot_open(struct inode inode, struct file filp)
	48	{
	49	struct snapshot_data *data;
c3e94d89	50	int error;
6e1819d6	51
a6e15a39 KC	52	if (!hibernation_available())
	53	return -EPERM;
	54
bcda53fa	55	lock_system_sleep();
25f2f3da RW	56
	57	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
	58	error = -EBUSY;
	59	goto Unlock;
	60	}
6e1819d6	61
1525a2ad	62	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
0709db60	63	atomic_inc(&snapshot_device_available);
25f2f3da RW	64	error = -ENOSYS;
25f2f3da RW	65	goto Unlock;
1525a2ad	66	}
6e1819d6 RW	67	nonseekable_open(inode, filp);
	68	data = &snapshot_state;
	69	filp->private_data = data;
	70	memset(&data->handle, 0, sizeof(struct snapshot_handle));
	71	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
c7510859	72	/* Hibernating. The image device should be accessible. */
915bae9e	73	data->swap = swsusp_resume_device ?
7bf23687	74	swap_type_of(swsusp_resume_device, 0, NULL) : -1;
6e1819d6	75	data->mode = O_RDONLY;
6a0c7cd3	76	data->free_bitmaps = false;
ebae2604	77	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
c3e94d89	78	if (error)
ebae2604	79	pm_notifier_call_chain(PM_POST_HIBERNATION);
6e1819d6	80	} else {
c7510859 RW	81	/*
	82	* Resuming. We may need to wait for the image device to
	83	* appear.
	84	*/
	85	wait_for_device_probe();
c7510859	86
6e1819d6 RW	87	data->swap = -1;
6e1819d6 RW	88	data->mode = O_WRONLY;
ebae2604	89	error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
aab17289 RW	90	if (!error) {
	91	error = create_basic_memory_bitmaps();
	92	data->free_bitmaps = !error;
	93	}
c3e94d89	94	if (error)
ebae2604	95	pm_notifier_call_chain(PM_POST_RESTORE);
c3e94d89	96	}
8fd37a4c	97	if (error)
c3e94d89	98	atomic_inc(&snapshot_device_available);
8fd37a4c	99
7bc9b1cf RW	100	data->frozen = false;
	101	data->ready = false;
	102	data->platform_support = false;
6e1819d6	103
25f2f3da	104	Unlock:
bcda53fa	105	unlock_system_sleep();
25f2f3da RW	106
25f2f3da RW	107	return error;
6e1819d6 RW	108	}
	109
	110	static int snapshot_release(struct inode inode, struct file filp)
	111	{
	112	struct snapshot_data *data;
	113
bcda53fa	114	lock_system_sleep();
25f2f3da	115
6e1819d6 RW	116	swsusp_free();
6e1819d6 RW	117	data = filp->private_data;
d1d241cc	118	free_all_swap_pages(data->swap);
9744997a RW	119	if (data->frozen) {
9744997a RW	120	pm_restore_gfp_mask();
8fd37a4c	121	free_basic_memory_bitmaps();
6e1819d6	122	thaw_processes();
aab17289 RW	123	} else if (data->free_bitmaps) {
aab17289 RW	124	free_basic_memory_bitmaps();
9744997a	125	}
1497dd1d	126	pm_notifier_call_chain(data->mode == O_RDONLY ?
c3e94d89	127	PM_POST_HIBERNATION : PM_POST_RESTORE);
0709db60	128	atomic_inc(&snapshot_device_available);
25f2f3da	129
bcda53fa	130	unlock_system_sleep();
25f2f3da	131
6e1819d6 RW	132	return 0;
	133	}
	134
	135	static ssize_t snapshot_read(struct file filp, char __user buf,
	136	size_t count, loff_t *offp)
	137	{
	138	struct snapshot_data *data;
	139	ssize_t res;
d3c1b24c	140	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	141
bcda53fa	142	lock_system_sleep();
25f2f3da	143
6e1819d6	144	data = filp->private_data;
25f2f3da RW	145	if (!data->ready) {
	146	res = -ENODATA;
	147	goto Unlock;
	148	}
d3c1b24c JS	149	if (!pg_offp) { /* on page boundary? */
	150	res = snapshot_read_next(&data->handle);
	151	if (res <= 0)
	152	goto Unlock;
	153	} else {
	154	res = PAGE_SIZE - pg_offp;
6e1819d6	155	}
25f2f3da	156
d3c1b24c JS	157	res = simple_read_from_buffer(buf, count, &pg_offp,
	158	data_of(data->handle), res);
	159	if (res > 0)
	160	*offp += res;
	161
25f2f3da	162	Unlock:
bcda53fa	163	unlock_system_sleep();
25f2f3da	164
6e1819d6 RW	165	return res;
	166	}
	167
	168	static ssize_t snapshot_write(struct file filp, const char __user buf,
	169	size_t count, loff_t *offp)
	170	{
	171	struct snapshot_data *data;
	172	ssize_t res;
d3c1b24c	173	loff_t pg_offp = *offp & ~PAGE_MASK;
6e1819d6	174
bcda53fa	175	lock_system_sleep();
25f2f3da	176
6e1819d6	177	data = filp->private_data;
d3c1b24c JS	178
	179	if (!pg_offp) {
	180	res = snapshot_write_next(&data->handle);
	181	if (res <= 0)
	182	goto unlock;
	183	} else {
	184	res = PAGE_SIZE - pg_offp;
6e1819d6	185	}
25f2f3da	186
d3c1b24c JS	187	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
	188	buf, count);
	189	if (res > 0)
	190	*offp += res;
	191	unlock:
bcda53fa	192	unlock_system_sleep();
25f2f3da	193
6e1819d6 RW	194	return res;
	195	}
	196
52d11025 AC	197	static long snapshot_ioctl(struct file *filp, unsigned int cmd,
52d11025 AC	198	unsigned long arg)
6e1819d6 RW	199	{
	200	int error = 0;
	201	struct snapshot_data *data;
af508b34	202	loff_t size;
3aef83e0	203	sector_t offset;
6e1819d6 RW	204
	205	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
	206	return -ENOTTY;
	207	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
	208	return -ENOTTY;
	209	if (!capable(CAP_SYS_ADMIN))
	210	return -EPERM;
	211
25f2f3da RW	212	if (!mutex_trylock(&pm_mutex))
25f2f3da RW	213	return -EBUSY;
6e1819d6	214
942f4015	215	lock_device_hotplug();
25f2f3da	216	data = filp->private_data;
52d11025	217
6e1819d6 RW	218	switch (cmd) {
	219
	220	case SNAPSHOT_FREEZE:
	221	if (data->frozen)
	222	break;
1bfcf130	223
c3e94d89 AS	224	printk("Syncing filesystems ... ");
	225	sys_sync();
	226	printk("done.\n");
	227
1bfcf130	228	error = freeze_processes();
8fd37a4c RW	229	if (error)
	230	break;
	231
	232	error = create_basic_memory_bitmaps();
	233	if (error)
	234	thaw_processes();
	235	else
7bc9b1cf	236	data->frozen = true;
8fd37a4c	237
6e1819d6 RW	238	break;
	239
	240	case SNAPSHOT_UNFREEZE:
2f41dddb	241	if (!data->frozen \|\| data->ready)
6e1819d6	242	break;
c9e664f1	243	pm_restore_gfp_mask();
8fd37a4c	244	free_basic_memory_bitmaps();
aab17289	245	data->free_bitmaps = false;
6e1819d6	246	thaw_processes();
7bc9b1cf	247	data->frozen = false;
6e1819d6 RW	248	break;
6e1819d6 RW	249
b694e52e	250	case SNAPSHOT_CREATE_IMAGE:
6e1819d6 RW	251	if (data->mode != O_RDONLY \|\| !data->frozen \|\| data->ready) {
	252	error = -EPERM;
	253	break;
	254	}
c9e664f1	255	pm_restore_gfp_mask();
eb57c1cf	256	error = hibernation_snapshot(data->platform_support);
51d6ff7a	257	if (!error) {
cc5d207c	258	error = put_user(in_suspend, (int __user *)arg);
a556d5b5 SB	259	data->ready = !freezer_test_done && !error;
a556d5b5 SB	260	freezer_test_done = false;
97819a26	261	}
6e1819d6 RW	262	break;
	263
	264	case SNAPSHOT_ATOMIC_RESTORE:
8357376d	265	snapshot_write_finalize(&data->handle);
6e1819d6 RW	266	if (data->mode != O_WRONLY \|\| !data->frozen \|\|
	267	!snapshot_image_loaded(&data->handle)) {
	268	error = -EPERM;
	269	break;
	270	}
eb57c1cf	271	error = hibernation_restore(data->platform_support);
6e1819d6 RW	272	break;
	273
	274	case SNAPSHOT_FREE:
	275	swsusp_free();
	276	memset(&data->handle, 0, sizeof(struct snapshot_handle));
7bc9b1cf	277	data->ready = false;
181e9bde RW	278	/*
	279	* It is necessary to thaw kernel threads here, because
	280	* SNAPSHOT_CREATE_IMAGE may be invoked directly after
	281	* SNAPSHOT_FREE. In that case, if kernel threads were not
	282	* thawed, the preallocation of memory carried out by
	283	* hibernation_snapshot() might run into problems (i.e. it
	284	* might fail or even deadlock).
	285	*/
	286	thaw_kernel_threads();
6e1819d6 RW	287	break;
6e1819d6 RW	288
b694e52e	289	case SNAPSHOT_PREF_IMAGE_SIZE:
6e1819d6 RW	290	image_size = arg;
	291	break;
	292
af508b34 RW	293	case SNAPSHOT_GET_IMAGE_SIZE:
	294	if (!data->ready) {
	295	error = -ENODATA;
	296	break;
	297	}
	298	size = snapshot_get_image_size();
	299	size <<= PAGE_SHIFT;
	300	error = put_user(size, (loff_t __user *)arg);
	301	break;
	302
b694e52e	303	case SNAPSHOT_AVAIL_SWAP_SIZE:
af508b34 RW	304	size = count_swap_pages(data->swap, 1);
	305	size <<= PAGE_SHIFT;
	306	error = put_user(size, (loff_t __user *)arg);
6e1819d6 RW	307	break;
6e1819d6 RW	308
b694e52e	309	case SNAPSHOT_ALLOC_SWAP_PAGE:
6e1819d6 RW	310	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	311	error = -ENODEV;
	312	break;
	313	}
d1d241cc	314	offset = alloc_swapdev_block(data->swap);
6e1819d6 RW	315	if (offset) {
6e1819d6 RW	316	offset <<= PAGE_SHIFT;
cc5d207c	317	error = put_user(offset, (loff_t __user *)arg);
6e1819d6 RW	318	} else {
	319	error = -ENOSPC;
	320	}
	321	break;
	322
	323	case SNAPSHOT_FREE_SWAP_PAGES:
	324	if (data->swap < 0 \|\| data->swap >= MAX_SWAPFILES) {
	325	error = -ENODEV;
	326	break;
	327	}
d1d241cc	328	free_all_swap_pages(data->swap);
6e1819d6 RW	329	break;
6e1819d6 RW	330
9b238205 LT	331	case SNAPSHOT_S2RAM:
	332	if (!data->frozen) {
	333	error = -EPERM;
	334	break;
	335	}
6c961dfb RW	336	/*
	337	* Tasks are frozen and the notifiers have been called with
	338	* PM_HIBERNATION_PREPARE
	339	*/
	340	error = suspend_devices_and_enter(PM_SUSPEND_MEM);
7bc9b1cf	341	data->ready = false;
9b238205 LT	342	break;
9b238205 LT	343
eb57c1cf RW	344	case SNAPSHOT_PLATFORM_SUPPORT:
	345	data->platform_support = !!arg;
	346	break;
	347
	348	case SNAPSHOT_POWER_OFF:
	349	if (data->platform_support)
	350	error = hibernation_platform_enter();
	351	break;
	352
37b2ba12	353	case SNAPSHOT_SET_SWAP_AREA:
d1d241cc	354	if (swsusp_swap_in_use()) {
37b2ba12 RW	355	error = -EPERM;
	356	} else {
	357	struct resume_swap_area swap_area;
	358	dev_t swdev;
	359
	360	error = copy_from_user(&swap_area, (void __user *)arg,
	361	sizeof(struct resume_swap_area));
	362	if (error) {
	363	error = -EFAULT;
	364	break;
	365	}
	366
	367	/*
	368	* User space encodes device types as two-byte values,
	369	* so we need to recode them
	370	*/
d88d4050	371	swdev = new_decode_dev(swap_area.dev);
37b2ba12 RW	372	if (swdev) {
37b2ba12 RW	373	offset = swap_area.offset;
7bf23687	374	data->swap = swap_type_of(swdev, offset, NULL);
37b2ba12 RW	375	if (data->swap < 0)
	376	error = -ENODEV;
	377	} else {
	378	data->swap = -1;
	379	error = -EINVAL;
	380	}
	381	}
	382	break;
	383
6e1819d6 RW	384	default:
	385	error = -ENOTTY;
	386
	387	}
25f2f3da	388
942f4015	389	unlock_device_hotplug();
25f2f3da RW	390	mutex_unlock(&pm_mutex);
25f2f3da RW	391
6e1819d6 RW	392	return error;
	393	}
	394
c336078b BH	395	#ifdef CONFIG_COMPAT
	396
	397	struct compat_resume_swap_area {
	398	compat_loff_t offset;
	399	u32 dev;
	400	} __packed;
	401
	402	static long
	403	snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	404	{
	405	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
	406
	407	switch (cmd) {
	408	case SNAPSHOT_GET_IMAGE_SIZE:
	409	case SNAPSHOT_AVAIL_SWAP_SIZE:
	410	case SNAPSHOT_ALLOC_SWAP_PAGE: {
	411	compat_loff_t __user *uoffset = compat_ptr(arg);
	412	loff_t offset;
	413	mm_segment_t old_fs;
	414	int err;
	415
	416	old_fs = get_fs();
	417	set_fs(KERNEL_DS);
	418	err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
	419	set_fs(old_fs);
	420	if (!err && put_user(offset, uoffset))
	421	err = -EFAULT;
	422	return err;
	423	}
	424
	425	case SNAPSHOT_CREATE_IMAGE:
	426	return snapshot_ioctl(file, cmd,
	427	(unsigned long) compat_ptr(arg));
	428
	429	case SNAPSHOT_SET_SWAP_AREA: {
	430	struct compat_resume_swap_area __user *u_swap_area =
	431	compat_ptr(arg);
	432	struct resume_swap_area swap_area;
	433	mm_segment_t old_fs;
	434	int err;
	435
	436	err = get_user(swap_area.offset, &u_swap_area->offset);
	437	err \|= get_user(swap_area.dev, &u_swap_area->dev);
	438	if (err)
	439	return -EFAULT;
	440	old_fs = get_fs();
	441	set_fs(KERNEL_DS);
	442	err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
	443	(unsigned long) &swap_area);
	444	set_fs(old_fs);
	445	return err;
	446	}
	447
	448	default:
	449	return snapshot_ioctl(file, cmd, arg);
	450	}
	451	}
	452
	453	#endif /* CONFIG_COMPAT */
	454
15ad7cdc	455	static const struct file_operations snapshot_fops = {
6e1819d6 RW	456	.open = snapshot_open,
	457	.release = snapshot_release,
	458	.read = snapshot_read,
	459	.write = snapshot_write,
	460	.llseek = no_llseek,
52d11025	461	.unlocked_ioctl = snapshot_ioctl,
c336078b BH	462	#ifdef CONFIG_COMPAT
	463	.compat_ioctl = snapshot_compat_ioctl,
	464	#endif
6e1819d6 RW	465	};
	466
	467	static struct miscdevice snapshot_device = {
	468	.minor = SNAPSHOT_MINOR,
	469	.name = "snapshot",
	470	.fops = &snapshot_fops,
	471	};
	472
	473	static int __init snapshot_device_init(void)
	474	{
	475	return misc_register(&snapshot_device);
	476	};
	477
	478	device_initcall(snapshot_device_init);