PM: Separate hibernation code from suspend code

[ With Johannes Berg <johannes@sipsolutions.net> ]

Separate the hibernation (aka suspend to disk code) from the other suspend
code.  In particular:

 * Remove the definitions related to hibernation from include/linux/pm.h
 * Introduce struct hibernation_ops and a new hibernate() function to hibernate
   the system, defined in include/linux/suspend.h
 * Separate suspend code in kernel/power/main.c from hibernation-related code
   in kernel/power/disk.c and kernel/power/user.c (with the help of
   hibernation_ops)
 * Switch ACPI (the only user of pm_ops.pm_disk_mode) to hibernation_ops

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 131 insertions, 126 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 06331374d86..b5f0543ed84 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -30,30 +30,69 @@ char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
 sector_t swsusp_resume_block;
 
+enum {
+	HIBERNATION_INVALID,
+	HIBERNATION_PLATFORM,
+	HIBERNATION_TEST,
+	HIBERNATION_TESTPROC,
+	HIBERNATION_SHUTDOWN,
+	HIBERNATION_REBOOT,
+	/* keep last */
+	__HIBERNATION_AFTER_LAST
+};
+#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
+#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
+
+static int hibernation_mode = HIBERNATION_SHUTDOWN;
+
+struct hibernation_ops *hibernation_ops;
+
+/**
+ * hibernation_set_ops - set the global hibernate operations
+ * @ops: the hibernation operations to use in subsequent hibernation transitions
+ */
+
+void hibernation_set_ops(struct hibernation_ops *ops)
+{
+	if (ops && !(ops->prepare && ops->enter && ops->finish)) {
+		WARN_ON(1);
+		return;
+	}
+	mutex_lock(&pm_mutex);
+	hibernation_ops = ops;
+	if (ops)
+		hibernation_mode = HIBERNATION_PLATFORM;
+	else if (hibernation_mode == HIBERNATION_PLATFORM)
+		hibernation_mode = HIBERNATION_SHUTDOWN;
+
+	mutex_unlock(&pm_mutex);
+}
+
+
 /**
  *	platform_prepare - prepare the machine for hibernation using the
  *	platform driver if so configured and return an error code if it fails
  */
 
-static inline int platform_prepare(void)
+static int platform_prepare(void)
 {
-	int error = 0;
+	return (hibernation_mode == HIBERNATION_PLATFORM && hibernation_ops) ?
+		hibernation_ops->prepare() : 0;
+}
 
-	switch (pm_disk_mode) {
-	case PM_DISK_TEST:
-	case PM_DISK_TESTPROC:
-	case PM_DISK_SHUTDOWN:
-	case PM_DISK_REBOOT:
-		break;
-	default:
-		if (pm_ops && pm_ops->prepare)
-			error = pm_ops->prepare(PM_SUSPEND_DISK);
-	}
-	return error;
+/**
+ *	platform_finish - switch the machine to the normal mode of operation
+ *	using the platform driver (must be called after platform_prepare())
+ */
+
+static void platform_finish(void)
+{
+	if (hibernation_mode == HIBERNATION_PLATFORM && hibernation_ops)
+		hibernation_ops->finish();
 }
 
 /**
- *	power_down - Shut machine down for hibernate.
+ *	power_down - Shut the machine down for hibernation.
  *
  *	Use the platform driver, if configured so; otherwise try
  *	to power off or reboot.
@@ -61,20 +100,20 @@ static inline int platform_prepare(void)
 
 static void power_down(void)
 {
-	switch (pm_disk_mode) {
-	case PM_DISK_TEST:
-	case PM_DISK_TESTPROC:
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
 		break;
-	case PM_DISK_SHUTDOWN:
+	case HIBERNATION_SHUTDOWN:
 		kernel_power_off();
 		break;
-	case PM_DISK_REBOOT:
+	case HIBERNATION_REBOOT:
 		kernel_restart(NULL);
 		break;
-	default:
-		if (pm_ops && pm_ops->enter) {
+	case HIBERNATION_PLATFORM:
+		if (hibernation_ops) {
 			kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
-			pm_ops->enter(PM_SUSPEND_DISK);
+			hibernation_ops->enter();
 			break;
 		}
 	}
@@ -87,20 +126,6 @@ static void power_down(void)
 	while(1);
 }
 
-static inline void platform_finish(void)
-{
-	switch (pm_disk_mode) {
-	case PM_DISK_TEST:
-	case PM_DISK_TESTPROC:
-	case PM_DISK_SHUTDOWN:
-	case PM_DISK_REBOOT:
-		break;
-	default:
-		if (pm_ops && pm_ops->finish)
-			pm_ops->finish(PM_SUSPEND_DISK);
-	}
-}
-
 static void unprepare_processes(void)
 {
 	thaw_processes();
@@ -120,13 +145,10 @@ static int prepare_processes(void)
 }
 
 /**
- *	pm_suspend_disk - The granpappy of hibernation power management.
- *
- *	If not, then call swsusp to do its thing, then figure out how
- *	to power down the system.
+ *	hibernate - The granpappy of the built-in hibernation management
  */
 
-int pm_suspend_disk(void)
+int hibernate(void)
 {
 	int error;
 
@@ -143,7 +165,8 @@ int pm_suspend_disk(void)
 	if (error)
 		goto Finish;
 
-	if (pm_disk_mode == PM_DISK_TESTPROC) {
+	mutex_lock(&pm_mutex);
+	if (hibernation_mode == HIBERNATION_TESTPROC) {
 		printk("swsusp debug: Waiting for 5 seconds.\n");
 		mdelay(5000);
 		goto Thaw;
@@ -168,7 +191,7 @@ int pm_suspend_disk(void)
 	if (error)
 		goto Enable_cpus;
 
-	if (pm_disk_mode == PM_DISK_TEST) {
+	if (hibernation_mode == HIBERNATION_TEST) {
 		printk("swsusp debug: Waiting for 5 seconds.\n");
 		mdelay(5000);
 		goto Enable_cpus;
@@ -205,6 +228,7 @@ int pm_suspend_disk(void)
 	device_resume();
 	resume_console();
  Thaw:
+	mutex_unlock(&pm_mutex);
 	unprepare_processes();
  Finish:
 	free_basic_memory_bitmaps();
@@ -220,7 +244,7 @@ int pm_suspend_disk(void)
  *	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 pm_suspend_disk() ) if everything goes well.
+ *	return above (in hibernate() ) if everything goes well.
  *	Otherwise, we fail gracefully and return to the normally
  *	scheduled program.
  *
@@ -315,25 +339,26 @@ static int software_resume(void)
 late_initcall(software_resume);
 
 
-static const char * const pm_disk_modes[] = {
-	[PM_DISK_PLATFORM]	= "platform",
-	[PM_DISK_SHUTDOWN]	= "shutdown",
-	[PM_DISK_REBOOT]	= "reboot",
-	[PM_DISK_TEST]		= "test",
-	[PM_DISK_TESTPROC]	= "testproc",
+static const char * const hibernation_modes[] = {
+	[HIBERNATION_PLATFORM]	= "platform",
+	[HIBERNATION_SHUTDOWN]	= "shutdown",
+	[HIBERNATION_REBOOT]	= "reboot",
+	[HIBERNATION_TEST]	= "test",
+	[HIBERNATION_TESTPROC]	= "testproc",
 };
 
 /**
- *	disk - Control suspend-to-disk mode
+ *	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 pm_ops), powering off the system or rebooting the system
- *	(for testing) as well as the two test modes.
+ *	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 in pm_ops). However, the user may choose 'shutdown' or 'reboot'
- *	as alternatives, as well as the test modes 'test' and 'testproc'.
+ *	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
@@ -345,7 +370,7 @@ static const char * const pm_disk_modes[] = {
  *	'testproc'
  *
  *	It will only change to 'platform' if the system
- *	supports it (as determined from pm_ops->pm_disk_mode).
+ *	supports it (as determined by having hibernation_ops).
  */
 
 static ssize_t disk_show(struct kset *kset, char *buf)
@@ -353,28 +378,25 @@ static ssize_t disk_show(struct kset *kset, char *buf)
 	int i;
 	char *start = buf;
 
-	for (i = PM_DISK_PLATFORM; i < PM_DISK_MAX; i++) {
-		if (!pm_disk_modes[i])
+	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+		if (!hibernation_modes[i])
 			continue;
 		switch (i) {
-		case PM_DISK_SHUTDOWN:
-		case PM_DISK_REBOOT:
-		case PM_DISK_TEST:
-		case PM_DISK_TESTPROC:
+		case HIBERNATION_SHUTDOWN:
+		case HIBERNATION_REBOOT:
+		case HIBERNATION_TEST:
+		case HIBERNATION_TESTPROC:
 			break;
-		default:
-			if (pm_ops && pm_ops->enter &&
-			    (i == pm_ops->pm_disk_mode))
+		case HIBERNATION_PLATFORM:
+			if (hibernation_ops)
 				break;
 			/* not a valid mode, continue with loop */
 			continue;
 		}
-		if (i == pm_disk_mode)
-			buf += sprintf(buf, "[%s]", pm_disk_modes[i]);
+		if (i == hibernation_mode)
+			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 		else
-			buf += sprintf(buf, "%s", pm_disk_modes[i]);
-		if (i+1 != PM_DISK_MAX)
-			buf += sprintf(buf, " ");
+			buf += sprintf(buf, "%s ", hibernation_modes[i]);
 	}
 	buf += sprintf(buf, "\n");
 	return buf-start;
@@ -387,39 +409,38 @@ static ssize_t disk_store(struct kset *kset, const char *buf, size_t n)
 	int i;
 	int len;
 	char *p;
-	suspend_disk_method_t mode = 0;
+	int mode = HIBERNATION_INVALID;
 
 	p = memchr(buf, '\n', n);
 	len = p ? p - buf : n;
 
 	mutex_lock(&pm_mutex);
-	for (i = PM_DISK_PLATFORM; i < PM_DISK_MAX; i++) {
-		if (!strncmp(buf, pm_disk_modes[i], len)) {
+	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+		if (!strncmp(buf, hibernation_modes[i], len)) {
 			mode = i;
 			break;
 		}
 	}
-	if (mode) {
+	if (mode != HIBERNATION_INVALID) {
 		switch (mode) {
-		case PM_DISK_SHUTDOWN:
-		case PM_DISK_REBOOT:
-		case PM_DISK_TEST:
-		case PM_DISK_TESTPROC:
-			pm_disk_mode = mode;
+		case HIBERNATION_SHUTDOWN:
+		case HIBERNATION_REBOOT:
+		case HIBERNATION_TEST:
+		case HIBERNATION_TESTPROC:
+			hibernation_mode = mode;
 			break;
-		default:
-			if (pm_ops && pm_ops->enter &&
-			    (mode == pm_ops->pm_disk_mode))
-				pm_disk_mode = mode;
+		case HIBERNATION_PLATFORM:
+			if (hibernation_ops)
+				hibernation_mode = mode;
 			else
 				error = -EINVAL;
 		}
-	} else {
+	} else
 		error = -EINVAL;
-	}
 
-	pr_debug("PM: suspend-to-disk mode set to '%s'\n",
-		 pm_disk_modes[mode]);
+	if (!error)
+		pr_debug("PM: suspend-to-disk mode set to '%s'\n",
+			 hibernation_modes[mode]);
 	mutex_unlock(&pm_mutex);
 	return error ? error : n;
 }
diff --git a/kernel/power/main.c b/kernel/power/main.c
index f6dda685e7e..40d56a31245 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -30,7 +30,6 @@
 DEFINE_MUTEX(pm_mutex);
 
 struct pm_ops *pm_ops;
-suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
 
 /**
  *	pm_set_ops - Set the global power method table. 
@@ -41,10 +40,6 @@ void pm_set_ops(struct pm_ops * ops)
 {
 	mutex_lock(&pm_mutex);
 	pm_ops = ops;
-	if (ops && ops->pm_disk_mode != PM_DISK_INVALID) {
-		pm_disk_mode = ops->pm_disk_mode;
-	} else
-		pm_disk_mode = PM_DISK_SHUTDOWN;
 	mutex_unlock(&pm_mutex);
 }
 
@@ -184,24 +179,12 @@ static void suspend_finish(suspend_state_t state)
 static const char * const pm_states[PM_SUSPEND_MAX] = {
 	[PM_SUSPEND_STANDBY]	= "standby",
 	[PM_SUSPEND_MEM]	= "mem",
-	[PM_SUSPEND_DISK]	= "disk",
 };
 
 static inline int valid_state(suspend_state_t state)
 {
-	/* Suspend-to-disk does not really need low-level support.
-	 * It can work with shutdown/reboot if needed. If it isn't
-	 * configured, then it cannot be supported.
-	 */
-	if (state == PM_SUSPEND_DISK)
-#ifdef CONFIG_SOFTWARE_SUSPEND
-		return 1;
-#else
-		return 0;
-#endif
-
-	/* all other states need lowlevel support and need to be
-	 * valid to the lowlevel implementation, no valid callback
+	/* All states need lowlevel support and need to be valid
+	 * to the lowlevel implementation, no valid callback
 	 * implies that none are valid. */
 	if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
 		return 0;
@@ -229,11 +212,6 @@ static int enter_state(suspend_state_t state)
 	if (!mutex_trylock(&pm_mutex))
 		return -EBUSY;
 
-	if (state == PM_SUSPEND_DISK) {
-		error = pm_suspend_disk();
-		goto Unlock;
-	}
-
 	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 	if ((error = suspend_prepare(state)))
 		goto Unlock;
@@ -251,7 +229,7 @@ static int enter_state(suspend_state_t state)
 
 /**
  *	pm_suspend - Externally visible function for suspending system.
- *	@state:		Enumarted value of state to enter.
+ *	@state:		Enumerated value of state to enter.
  *
  *	Determine whether or not value is within range, get state 
  *	structure, and enter (above).
@@ -289,7 +267,13 @@ static ssize_t state_show(struct kset *kset, char *buf)
 		if (pm_states[i] && valid_state(i))
 			s += sprintf(s,"%s ", pm_states[i]);
 	}
-	s += sprintf(s,"\n");
+#ifdef CONFIG_SOFTWARE_SUSPEND
+	s += sprintf(s, "%s\n", "disk");
+#else
+	if (s != buf)
+		/* convert the last space to a newline */
+		*(s-1) = '\n';
+#endif
 	return (s - buf);
 }
 
@@ -304,6 +288,12 @@ static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 	p = memchr(buf, '\n', n);
 	len = p ? p - buf : n;
 
+	/* First, check if we are requested to hibernate */
+	if (!strncmp(buf, "disk", len)) {
+		error = hibernate();
+		return error ? error : n;
+	}
+
 	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 		if (*s && !strncmp(buf, *s, len))
 			break;
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 34b43542785..51381487103 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -25,12 +25,7 @@ struct swsusp_info {
  */
 #define SPARE_PAGES	((1024 * 1024) >> PAGE_SHIFT)
 
-extern int pm_suspend_disk(void);
-#else
-static inline int pm_suspend_disk(void)
-{
-	return -EPERM;
-}
+extern struct hibernation_ops *hibernation_ops;
 #endif
 
 extern int pfn_is_nosave(unsigned long);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 040560d9c31..24d7d78e6f4 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -130,16 +130,16 @@ static inline int platform_prepare(void)
 {
 	int error = 0;
 
-	if (pm_ops && pm_ops->prepare)
-		error = pm_ops->prepare(PM_SUSPEND_DISK);
+	if (hibernation_ops)
+		error = hibernation_ops->prepare();
 
 	return error;
 }
 
 static inline void platform_finish(void)
 {
-	if (pm_ops && pm_ops->finish)
-		pm_ops->finish(PM_SUSPEND_DISK);
+	if (hibernation_ops)
+		hibernation_ops->finish();
 }
 
 static inline int snapshot_suspend(int platform_suspend)
@@ -384,7 +384,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 		switch (arg) {
 
 		case PMOPS_PREPARE:
-			if (pm_ops && pm_ops->enter) {
+			if (hibernation_ops) {
 				data->platform_suspend = 1;
 				error = 0;
 			} else {
@@ -395,8 +395,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 		case PMOPS_ENTER:
 			if (data->platform_suspend) {
 				kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
-				error = pm_ops->enter(PM_SUSPEND_DISK);
-				error = 0;
+				error = hibernation_ops->enter();
 			}
 			break;