disk.c

linux 内核源代码

}

/**
 *	hibernate - The granpappy of the built-in hibernation management
 */

int hibernate(void)
{
	int error;

	mutex_lock(&pm_mutex);
	/* The snapshot device should not be opened while we're running */
	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		goto Unlock;
	}

	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
	if (error)
		goto Exit;

	/* Allocate memory management structures */
	error = create_basic_memory_bitmaps();
	if (error)
		goto Exit;

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

	error = prepare_processes();
	if (error)
		goto Finish;

	if (hibernation_mode == HIBERNATION_TESTPROC) {
		printk("swsusp debug: Waiting for 5 seconds.\n");
		mdelay(5000);
		goto Thaw;
	}
	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
	if (in_suspend && !error) {
		unsigned int flags = 0;

		if (hibernation_mode == HIBERNATION_PLATFORM)
			flags |= SF_PLATFORM_MODE;
		pr_debug("PM: writing image.\n");
		error = swsusp_write(flags);
		swsusp_free();
		if (!error)
			power_down();
	} else {
		pr_debug("PM: Image restored successfully.\n");
		swsusp_free();
	}
 Thaw:
	unprepare_processes();
 Finish:
	free_basic_memory_bitmaps();
 Exit:
	pm_notifier_call_chain(PM_POST_HIBERNATION);
	atomic_inc(&snapshot_device_available);
 Unlock:
	mutex_unlock(&pm_mutex);
	return error;
}


/**
 *	software_resume - Resume from a saved image.
 *
 *	Called as a late_initcall (so all devices are discovered and
 *	initialized), we call swsusp to see if we have a saved image or not.
 *	If so, we quiesce devices, the restore the saved image. We will
 *	return above (in hibernate() ) if everything goes well.
 *	Otherwise, we fail gracefully and return to the normally
 *	scheduled program.
 *
 */

static int software_resume(void)
{
	int error;
	unsigned int flags;

	/*
	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
	 * is configured into the kernel. Since the regular hibernate
	 * trigger path is via sysfs which takes a buffer mutex before
	 * calling hibernate functions (which take pm_mutex) this can
	 * cause lockdep to complain about a possible ABBA deadlock
	 * which cannot happen since we're in the boot code here and
	 * sysfs can't be invoked yet. Therefore, we use a subclass
	 * here to avoid lockdep complaining.
	 */
	mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
	if (!swsusp_resume_device) {
		if (!strlen(resume_file)) {
			mutex_unlock(&pm_mutex);
			return -ENOENT;
		}
		swsusp_resume_device = name_to_dev_t(resume_file);
		pr_debug("swsusp: Resume From Partition %s\n", resume_file);
	} else {
		pr_debug("swsusp: Resume From Partition %d:%d\n",
			 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
	}

	if (noresume) {
		/**
		 * FIXME: If noresume is specified, we need to find the partition
		 * and reset it back to normal swap space.
		 */
		mutex_unlock(&pm_mutex);
		return 0;
	}

	pr_debug("PM: Checking swsusp image.\n");
	error = swsusp_check();
	if (error)
		goto Unlock;

	/* The snapshot device should not be opened while we're running */
	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
		error = -EBUSY;
		goto Unlock;
	}

	error = create_basic_memory_bitmaps();
	if (error)
		goto Finish;

	pr_debug("PM: Preparing processes for restore.\n");
	error = prepare_processes();
	if (error) {
		swsusp_close();
		goto Done;
	}

	pr_debug("PM: Reading swsusp image.\n");

	error = swsusp_read(&flags);
	if (!error)
		hibernation_restore(flags & SF_PLATFORM_MODE);

	printk(KERN_ERR "PM: Restore failed, recovering.\n");
	swsusp_free();
	unprepare_processes();
 Done:
	free_basic_memory_bitmaps();
 Finish:
	atomic_inc(&snapshot_device_available);
	/* For success case, the suspend path will release the lock */
 Unlock:
	mutex_unlock(&pm_mutex);
	pr_debug("PM: Resume from disk failed.\n");
	return error;
}

late_initcall(software_resume);


static const char * const hibernation_modes[] = {
	[HIBERNATION_PLATFORM]	= "platform",
	[HIBERNATION_SHUTDOWN]	= "shutdown",
	[HIBERNATION_REBOOT]	= "reboot",
	[HIBERNATION_TEST]	= "test",
	[HIBERNATION_TESTPROC]	= "testproc",
};

/**
 *	disk - Control hibernation mode
 *
 *	Suspend-to-disk can be handled in several ways. We have a few options
 *	for putting the system to sleep - using the platform driver (e.g. ACPI
 *	or other hibernation_ops), powering off the system or rebooting the
 *	system (for testing) as well as the two test modes.
 *
 *	The system can support 'platform', and that is known a priori (and
 *	encoded by the presence of hibernation_ops). However, the user may
 *	choose 'shutdown' or 'reboot' as alternatives, as well as one fo the
 *	test modes, 'test' or 'testproc'.
 *
 *	show() will display what the mode is currently set to.
 *	store() will accept one of
 *
 *	'platform'
 *	'shutdown'
 *	'reboot'
 *	'test'
 *	'testproc'
 *
 *	It will only change to 'platform' if the system
 *	supports it (as determined by having hibernation_ops).
 */

static ssize_t disk_show(struct kset *kset, char *buf)
{
	int i;
	char *start = buf;

	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
		if (!hibernation_modes[i])
			continue;
		switch (i) {
		case HIBERNATION_SHUTDOWN:
		case HIBERNATION_REBOOT:
		case HIBERNATION_TEST:
		case HIBERNATION_TESTPROC:
			break;
		case HIBERNATION_PLATFORM:
			if (hibernation_ops)
				break;
			/* not a valid mode, continue with loop */
			continue;
		}
		if (i == hibernation_mode)
			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
		else
			buf += sprintf(buf, "%s ", hibernation_modes[i]);
	}
	buf += sprintf(buf, "\n");
	return buf-start;
}


static ssize_t disk_store(struct kset *kset, const char *buf, size_t n)
{
	int error = 0;
	int i;
	int len;
	char *p;
	int mode = HIBERNATION_INVALID;

	p = memchr(buf, '\n', n);
	len = p ? p - buf : n;

	mutex_lock(&pm_mutex);
	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
		if (len == strlen(hibernation_modes[i])
		    && !strncmp(buf, hibernation_modes[i], len)) {
			mode = i;
			break;
		}
	}
	if (mode != HIBERNATION_INVALID) {
		switch (mode) {
		case HIBERNATION_SHUTDOWN:
		case HIBERNATION_REBOOT:
		case HIBERNATION_TEST:
		case HIBERNATION_TESTPROC:
			hibernation_mode = mode;
			break;
		case HIBERNATION_PLATFORM:
			if (hibernation_ops)
				hibernation_mode = mode;
			else
				error = -EINVAL;
		}
	} else
		error = -EINVAL;

	if (!error)
		pr_debug("PM: suspend-to-disk mode set to '%s'\n",
			 hibernation_modes[mode]);
	mutex_unlock(&pm_mutex);
	return error ? error : n;
}

power_attr(disk);

static ssize_t resume_show(struct kset *kset, char *buf)
{
	return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
		       MINOR(swsusp_resume_device));
}

static ssize_t resume_store(struct kset *kset, const char *buf, size_t n)
{
	unsigned int maj, min;
	dev_t res;
	int ret = -EINVAL;

	if (sscanf(buf, "%u:%u", &maj, &min) != 2)
		goto out;

	res = MKDEV(maj,min);
	if (maj != MAJOR(res) || min != MINOR(res))
		goto out;

	mutex_lock(&pm_mutex);
	swsusp_resume_device = res;
	mutex_unlock(&pm_mutex);
	printk("Attempting manual resume\n");
	noresume = 0;
	software_resume();
	ret = n;
 out:
	return ret;
}

power_attr(resume);

static ssize_t image_size_show(struct kset *kset, char *buf)
{
	return sprintf(buf, "%lu\n", image_size);
}

static ssize_t image_size_store(struct kset *kset, const char *buf, size_t n)
{
	unsigned long size;

	if (sscanf(buf, "%lu", &size) == 1) {
		image_size = size;
		return n;
	}

	return -EINVAL;
}

power_attr(image_size);

static struct attribute * g[] = {
	&disk_attr.attr,
	&resume_attr.attr,
	&image_size_attr.attr,
	NULL,
};


static struct attribute_group attr_group = {
	.attrs = g,
};


static int __init pm_disk_init(void)
{
	return sysfs_create_group(&power_subsys.kobj, &attr_group);
}

core_initcall(pm_disk_init);


static int __init resume_setup(char *str)
{
	if (noresume)
		return 1;

	strncpy( resume_file, str, 255 );
	return 1;
}

static int __init resume_offset_setup(char *str)
{
	unsigned long long offset;

	if (noresume)
		return 1;

	if (sscanf(str, "%llu", &offset) == 1)
		swsusp_resume_block = offset;

	return 1;
}

static int __init noresume_setup(char *str)
{
	noresume = 1;
	return 1;
}

__setup("noresume", noresume_setup);
__setup("resume_offset=", resume_offset_setup);
__setup("resume=", resume_setup);