Hibernation: Rework platform support ioctls (rev. 2)

Modify the hibernation userland interface by adding two new ioctls to it,
SNAPSHOT_PLATFORM_SUPPORT and SNAPSHOT_POWER_OFF, that can be used,
respectively, to switch the hibernation platform support on/off and to make the
kernel transition the system to the hibernation state (eg. ACPI S4) using the
platform (eg. ACPI) driver.

These ioctls are intended to replace the misdesigned SNAPSHOT_PMOPS ioctl,
which from now is regarded as obsolete and will be removed in the future.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 32 insertions, 16 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 23c17031ed2..6ca85fd4975 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -156,15 +156,12 @@ struct resume_swap_area {
 #define SNAPSHOT_FREE_SWAP_PAGES	_IO(SNAPSHOT_IOC_MAGIC, 9)
 #define SNAPSHOT_SET_SWAP_FILE		_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
 #define SNAPSHOT_S2RAM			_IO(SNAPSHOT_IOC_MAGIC, 11)
-#define SNAPSHOT_PMOPS			_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
 #define SNAPSHOT_SET_SWAP_AREA		_IOW(SNAPSHOT_IOC_MAGIC, 13, \
 							struct resume_swap_area)
 #define SNAPSHOT_GET_IMAGE_SIZE		_IOR(SNAPSHOT_IOC_MAGIC, 14, loff_t)
-#define SNAPSHOT_IOC_MAXNR	14
-
-#define PMOPS_PREPARE	1
-#define PMOPS_ENTER	2
-#define PMOPS_FINISH	3
+#define SNAPSHOT_PLATFORM_SUPPORT	_IO(SNAPSHOT_IOC_MAGIC, 15)
+#define SNAPSHOT_POWER_OFF		_IO(SNAPSHOT_IOC_MAGIC, 16)
+#define SNAPSHOT_IOC_MAXNR	16
 
 /* If unset, the snapshot device cannot be open. */
 extern atomic_t snapshot_device_available;
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 88aac26e598..de3fb433ae3 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -28,6 +28,18 @@
 
 #include "power.h"
 
+/*
+ * NOTE: The SNAPSHOT_PMOPS ioctl is obsolete and will be removed in the
+ * future.  It is only preserved here for compatibility with existing userland
+ * utilities.
+ */
+#define SNAPSHOT_PMOPS		_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
+
+#define PMOPS_PREPARE	1
+#define PMOPS_ENTER	2
+#define PMOPS_FINISH	3
+
+
 #define SNAPSHOT_MINOR	231
 
 static struct snapshot_data {
@@ -36,7 +48,7 @@ static struct snapshot_data {
 	int mode;
 	char frozen;
 	char ready;
-	char platform_suspend;
+	char platform_support;
 } snapshot_state;
 
 atomic_t snapshot_device_available = ATOMIC_INIT(1);
@@ -70,7 +82,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
 	}
 	data->frozen = 0;
 	data->ready = 0;
-	data->platform_suspend = 0;
+	data->platform_support = 0;
 
 	return 0;
 }
@@ -183,7 +195,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 			error = -EPERM;
 			break;
 		}
-		error = hibernation_snapshot(data->platform_suspend);
+		error = hibernation_snapshot(data->platform_support);
 		if (!error)
 			error = put_user(in_suspend, (unsigned int __user *)arg);
 		if (!error)
@@ -197,7 +209,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 			error = -EPERM;
 			break;
 		}
-		error = hibernation_restore(data->platform_suspend);
+		error = hibernation_restore(data->platform_support);
 		break;
 
 	case SNAPSHOT_FREE:
@@ -285,26 +297,33 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 		mutex_unlock(&pm_mutex);
 		break;
 
-	case SNAPSHOT_PMOPS:
+	case SNAPSHOT_PLATFORM_SUPPORT:
+		data->platform_support = !!arg;
+		break;
+
+	case SNAPSHOT_POWER_OFF:
+		if (data->platform_support)
+			error = hibernation_platform_enter();
+		break;
+
+	case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 		error = -EINVAL;
 
 		switch (arg) {
 
 		case PMOPS_PREPARE:
-			data->platform_suspend = 1;
+			data->platform_support = 1;
 			error = 0;
 			break;
 
 		case PMOPS_ENTER:
-			if (data->platform_suspend)
+			if (data->platform_support)
 				error = hibernation_platform_enter();
-
 			break;
 
 		case PMOPS_FINISH:
-			if (data->platform_suspend)
+			if (data->platform_support)
 				error = 0;
-
 			break;
 
 		default: