PM: Reduce code duplication between main.c and user.c

The SNAPSHOT_S2RAM ioctl code is outdated and it should not duplicate the
suspend code in kernel/power/main.c.  Fix that.

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

3 files changed, 62 insertions, 78 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 4d26ad394fb3..32147b57c3bf 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -65,14 +65,11 @@ static inline void pm_finish(suspend_state_t state)
 
 /**
  *      suspend_prepare - Do prep work before entering low-power state.
- *      @state:         State we're entering.
  *
- *      This is common code that is called for each state that we're 
- *      entering. Allocate a console, stop all processes, then make sure
- *      the platform can enter the requested state.
+ *      This is common code that is called for each state that we're entering.
+ *      Run suspend notifiers, allocate a console and stop all processes.
  */
-
-static int suspend_prepare(suspend_state_t state)
+static int suspend_prepare(void)
 {
         int error;
         unsigned int free_pages;
@@ -91,43 +88,18 @@ static int suspend_prepare(suspend_state_t state)
                 goto Thaw;
         }
 
-        if ((free_pages = global_page_state(NR_FREE_PAGES))
-                        < FREE_PAGE_NUMBER) {
+        free_pages = global_page_state(NR_FREE_PAGES);
+        if (free_pages < FREE_PAGE_NUMBER) {
                 pr_debug("PM: free some memory\n");
                 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
                 if (nr_free_pages() < FREE_PAGE_NUMBER) {
                         error = -ENOMEM;
                         printk(KERN_ERR "PM: No enough memory\n");
-                        goto Thaw;
                 }
         }
-
-        if (pm_ops->set_target) {
-                error = pm_ops->set_target(state);
-                if (error)
-                        goto Thaw;
-        }
-        suspend_console();
-        error = device_suspend(PMSG_SUSPEND);
-        if (error) {
-                printk(KERN_ERR "Some devices failed to suspend\n");
-                goto Resume_console;
-        }
-        if (pm_ops->prepare) {
-                if ((error = pm_ops->prepare(state)))
-                        goto Resume_devices;
-        }
-
-        error = disable_nonboot_cpus();
         if (!error)
                 return 0;
 
-        enable_nonboot_cpus();
-        pm_finish(state);
- Resume_devices:
-        device_resume();
- Resume_console:
-        resume_console();
  Thaw:
         thaw_processes();
         pm_restore_console();
@@ -148,6 +120,12 @@ void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
         local_irq_enable();
 }
 
+/**
+ *      suspend_enter - enter the desired system sleep state.
+ *      @state:         state to enter
+ *
+ *      This function should be called after devices have been suspended.
+ */
 int suspend_enter(suspend_state_t state)
 {
         int error = 0;
@@ -167,21 +145,55 @@ int suspend_enter(suspend_state_t state)
         return error;
 }
 
+/**
+ *      suspend_devices_and_enter - suspend devices and enter the desired system sleep
+ *                        state.
+ *      @state:           state to enter
+ */
+int suspend_devices_and_enter(suspend_state_t state)
+{
+        int error;
+
+        if (!pm_ops)
+                return -ENOSYS;
+
+        if (pm_ops->set_target) {
+                error = pm_ops->set_target(state);
+                if (error)
+                        return error;
+        }
+        suspend_console();
+        error = device_suspend(PMSG_SUSPEND);
+        if (error) {
+                printk(KERN_ERR "Some devices failed to suspend\n");
+                goto Resume_console;
+        }
+        if (pm_ops->prepare) {
+                error = pm_ops->prepare(state);
+                if (error)
+                        goto Resume_devices;
+        }
+        error = disable_nonboot_cpus();
+        if (!error)
+                suspend_enter(state);
+
+        enable_nonboot_cpus();
+        pm_finish(state);
+ Resume_devices:
+        device_resume();
+ Resume_console:
+        resume_console();
+        return error;
+}
 
 /**
  *      suspend_finish - Do final work before exiting suspend sequence.
- *      @state:         State we're coming out of.
  *
  *      Call platform code to clean up, restart processes, and free the 
  *      console that we've allocated. This is not called for suspend-to-disk.
  */
-
-static void suspend_finish(suspend_state_t state)
+static void suspend_finish(void)
 {
-        enable_nonboot_cpus();
-        pm_finish(state);
-        device_resume();
-        resume_console();
         thaw_processes();
         pm_restore_console();
         pm_notifier_call_chain(PM_POST_SUSPEND);
@@ -216,7 +228,6 @@ static inline int valid_state(suspend_state_t state)
  *      Then, do the setup for suspend, enter the state, and cleaup (after
  *      we've woken up).
  */
-
 static int enter_state(suspend_state_t state)
 {
         int error;
@@ -227,14 +238,14 @@ static int enter_state(suspend_state_t state)
                 return -EBUSY;
 
         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
-        if ((error = suspend_prepare(state)))
+        if ((error = suspend_prepare()))
                 goto Unlock;
 
         pr_debug("PM: Entering %s sleep\n", pm_states[state]);
-        error = suspend_enter(state);
+        error = suspend_devices_and_enter(state);
 
         pr_debug("PM: Finishing wakeup.\n");
-        suspend_finish(state);
+        suspend_finish();
  Unlock:
         mutex_unlock(&pm_mutex);
         return error;
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 01c2275b15b2..5f24c786f8ec 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -170,7 +170,6 @@ extern int swsusp_resume(void);
 extern int swsusp_read(unsigned int *flags_p);
 extern int swsusp_write(unsigned int flags);
 extern void swsusp_close(void);
-extern int suspend_enter(suspend_state_t state);
 
 struct timeval;
 /* kernel/power/swsusp.c */
@@ -178,6 +177,8 @@ extern void swsusp_show_speed(struct timeval *, struct timeval *,
                                 unsigned int, char *);
 
 /* kernel/power/main.c */
+extern int suspend_enter(suspend_state_t state);
+extern int suspend_devices_and_enter(suspend_state_t state);
 extern struct blocking_notifier_head pm_chain_head;
 
 static inline int pm_notifier_call_chain(unsigned long val)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 7f19afe01b48..bd0723a7df3f 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -255,47 +255,19 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                 break;
 
         case SNAPSHOT_S2RAM:
-                if (!pm_ops) {
-                        error = -ENOSYS;
-                        break;
-                }
-
                 if (!data->frozen) {
                         error = -EPERM;
                         break;
                 }
-
                 if (!mutex_trylock(&pm_mutex)) {
                         error = -EBUSY;
                         break;
                 }
-
-                if (pm_ops->prepare) {
-                        error = pm_ops->prepare(PM_SUSPEND_MEM);
-                        if (error)
-                                goto OutS3;
-                }
-
-                /* Put devices to sleep */
-                suspend_console();
-                error = device_suspend(PMSG_SUSPEND);
-                if (error) {
-                        printk(KERN_ERR "Failed to suspend some devices.\n");
-                } else {
-                        error = disable_nonboot_cpus();
-                        if (!error) {
-                                /* Enter S3, system is already frozen */
-                                suspend_enter(PM_SUSPEND_MEM);
-                                enable_nonboot_cpus();
-                        }
-                        /* Wake up devices */
-                        device_resume();
-                }
-                resume_console();
-                if (pm_ops->finish)
-                        pm_ops->finish(PM_SUSPEND_MEM);
-
- OutS3:
+                /*
+                 * Tasks are frozen and the notifiers have been called with
+                 * PM_HIBERNATION_PREPARE
+                 */
+                error = suspend_devices_and_enter(PM_SUSPEND_MEM);
                 mutex_unlock(&pm_mutex);
                 break;