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 23c17031ed21..6ca85fd4975f 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 88aac26e598a..de3fb433ae39 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+ * NOTE: The SNAPSHOT_PMOPS ioctl is obsolete and will be removed in the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: