[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>

1 files changed, 58 insertions, 34 deletions

diff --git a/kernel/power/user.c b/kernel/power/user.c
index f7b7a785a5c6..4f217683455f 100644
--- 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: