[PATCH] swsusp: add s2ram ioctl to userland interface

Add the SNAPSHOT_S2RAM ioctl to the snapshot device.

This ioctl allows a userland application to make the system (previously frozen
with the SNAPSHOT_FREE ioctl) enter the S3 state without freezing processes
and disabling nonboot CPUs for the second time.

This will allow us to implement the suspend-to-disk-and-RAM (STDR)
functionality in the userland suspend tools.

Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 40 insertions, 2 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 9cb235cba4a9..ee371f50ccaa 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -103,7 +103,7 @@ static int suspend_prepare(suspend_state_t state)
 }
 
 
-static int suspend_enter(suspend_state_t state)
+int suspend_enter(suspend_state_t state)
 {
         int error = 0;
         unsigned long flags;
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 42c431c8bdde..f06f12f21767 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -77,7 +77,8 @@ int snapshot_image_loaded(struct snapshot_handle *handle);
 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
 #define SNAPSHOT_FREE_SWAP_PAGES        _IO(SNAPSHOT_IOC_MAGIC, 9)
 #define SNAPSHOT_SET_SWAP_FILE          _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
-#define SNAPSHOT_IOC_MAXNR      10
+#define SNAPSHOT_S2RAM                  _IO(SNAPSHOT_IOC_MAGIC, 11)
+#define SNAPSHOT_IOC_MAXNR      11
 
 /**
  *      The bitmap is used for tracing allocated swap pages
@@ -112,3 +113,4 @@ extern int swsusp_resume(void);
 extern int swsusp_read(void);
 extern int swsusp_write(void);
 extern void swsusp_close(void);
+extern int suspend_enter(suspend_state_t state);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index bbd4842104aa..3f1539fbe48a 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -266,6 +266,42 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                 }
                 break;
 
+        case SNAPSHOT_S2RAM:
+                if (!data->frozen) {
+                        error = -EPERM;
+                        break;
+                }
+
+                if (down_trylock(&pm_sem)) {
+                        error = -EBUSY;
+                        break;
+                }
+
+                if (pm_ops->prepare) {
+                        error = pm_ops->prepare(PM_SUSPEND_MEM);
+                        if (error)
+                                goto OutS3;
+                }
+
+                /* Put devices to sleep */
+                error = device_suspend(PMSG_SUSPEND);
+                if (error) {
+                        printk(KERN_ERR "Failed to suspend some devices.\n");
+                } else {
+                        /* Enter S3, system is already frozen */
+                        suspend_enter(PM_SUSPEND_MEM);
+
+                        /* Wake up devices */
+                        device_resume();
+                }
+
+                if (pm_ops->finish)
+                        pm_ops->finish(PM_SUSPEND_MEM);
+
+OutS3:
+                up(&pm_sem);
+                break;
+
         default:
                 error = -ENOTTY;