[PATCH] swsusp: Change code ordering in user.c

Change the ordering of code in kernel/power/user.c so that device_suspend() is
called before disable_nonboot_cpus() and device_resume() is called after
enable_nonboot_cpus().  This is needed to make the userland suspend call
pm_ops->finish() after enable_nonboot_cpus() and before device_resume(), as
indicated by the recent discussion on Linux-PM (cf.
http://lists.osdl.org/pipermail/linux-pm/2006-November/004164.html).

The changes here only affect the userland interface of swsusp.

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

diff --git a/kernel/power/user.c b/kernel/power/user.c
index f7b7a785a5c60a35e133daa036f7b9667ce3d718..4f217683455ff6a81b42d89d779085a4d30e13dc 100644 (file)
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -122,6 +122,59 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
        return res;
 }
 
+static inline int snapshot_suspend(void)
+{
+       int error;
+
+       mutex_lock(&pm_mutex);
+       /* Free memory before shutting down devices. */
+       error = swsusp_shrink_memory();
+       if (error)
+               goto Finish;
+
+       suspend_console();
+       error = device_suspend(PMSG_FREEZE);
+       if (error)
+               goto Resume_devices;
+
+       error = disable_nonboot_cpus();
+       if (!error) {
+               in_suspend = 1;
+               error = swsusp_suspend();
+       }
+       enable_nonboot_cpus();
+ Resume_devices:
+       device_resume();
+       resume_console();
+ Finish:
+       mutex_unlock(&pm_mutex);
+       return error;
+}
+
+static inline int snapshot_restore(void)
+{
+       int error;
+
+       mutex_lock(&pm_mutex);
+       pm_prepare_console();
+       suspend_console();
+       error = device_suspend(PMSG_PRETHAW);
+       if (error)
+               goto Resume_devices;
+
+       error = disable_nonboot_cpus();
+       if (!error)
+               error = swsusp_resume();
+
+       enable_nonboot_cpus();
+ Resume_devices:
+       device_resume();
+       resume_console();
+       pm_restore_console();
+       mutex_unlock(&pm_mutex);
+       return error;
+}
+
 static int snapshot_ioctl(struct inode *inode, struct file *filp,
                           unsigned int cmd, unsigned long arg)
 {
@@ -145,14 +198,9 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                if (data->frozen)
                        break;
                mutex_lock(&pm_mutex);
-               error = disable_nonboot_cpus();
-               if (!error) {
-                       error = freeze_processes();
-                       if (error) {
-                               thaw_processes();
-                               enable_nonboot_cpus();
-                               error = -EBUSY;
-                       }
+               if (freeze_processes()) {
+                       thaw_processes();
+                       error = -EBUSY;
                }
                mutex_unlock(&pm_mutex);
                if (!error)
@@ -164,7 +212,6 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                        break;
                mutex_lock(&pm_mutex);
                thaw_processes();
-               enable_nonboot_cpus();
                mutex_unlock(&pm_mutex);
                data->frozen = 0;
                break;
@@ -174,20 +221,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                        error = -EPERM;
                        break;
                }
-               mutex_lock(&pm_mutex);
-               /* Free memory before shutting down devices. */
-               error = swsusp_shrink_memory();
-               if (!error) {
-                       suspend_console();
-                       error = device_suspend(PMSG_FREEZE);
-                       if (!error) {
-                               in_suspend = 1;
-                               error = swsusp_suspend();
-                               device_resume();
-                       }
-                       resume_console();
-               }
-               mutex_unlock(&pm_mutex);
+               error = snapshot_suspend();
                if (!error)
                        error = put_user(in_suspend, (unsigned int __user *)arg);
                if (!error)
@@ -201,17 +235,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                        error = -EPERM;
                        break;
                }
-               mutex_lock(&pm_mutex);
-               pm_prepare_console();
-               suspend_console();
-               error = device_suspend(PMSG_PRETHAW);
-               if (!error) {
-                       error = swsusp_resume();
-                       device_resume();
-               }
-               resume_console();
-               pm_restore_console();
-               mutex_unlock(&pm_mutex);
+               error = snapshot_restore();
                break;
 
        case SNAPSHOT_FREE: