PM: Separate hibernation code from suspend code

[ With Johannes Berg <johannes@sipsolutions.net> ]

Separate the hibernation (aka suspend to disk code) from the other suspend
code.  In particular:

 * Remove the definitions related to hibernation from include/linux/pm.h
 * Introduce struct hibernation_ops and a new hibernate() function to hibernate
   the system, defined in include/linux/suspend.h
 * Separate suspend code in kernel/power/main.c from hibernation-related code
   in kernel/power/disk.c and kernel/power/user.c (with the help of
   hibernation_ops)
 * Switch ACPI (the only user of pm_ops.pm_disk_mode) to hibernation_ops

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: 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>

1 files changed, 16 insertions, 26 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index f6dda685e7e2..40d56a31245e 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -30,7 +30,6 @@
 DEFINE_MUTEX(pm_mutex);
 
 struct pm_ops *pm_ops;
-suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
 
 /**
  *      pm_set_ops - Set the global power method table. 
@@ -41,10 +40,6 @@ void pm_set_ops(struct pm_ops * ops)
 {
         mutex_lock(&pm_mutex);
         pm_ops = ops;
-        if (ops && ops->pm_disk_mode != PM_DISK_INVALID) {
-                pm_disk_mode = ops->pm_disk_mode;
-        } else
-                pm_disk_mode = PM_DISK_SHUTDOWN;
         mutex_unlock(&pm_mutex);
 }
 
@@ -184,24 +179,12 @@ static void suspend_finish(suspend_state_t state)
 static const char * const pm_states[PM_SUSPEND_MAX] = {
         [PM_SUSPEND_STANDBY]    = "standby",
         [PM_SUSPEND_MEM]        = "mem",
-        [PM_SUSPEND_DISK]       = "disk",
 };
 
 static inline int valid_state(suspend_state_t state)
 {
-        /* Suspend-to-disk does not really need low-level support.
-         * It can work with shutdown/reboot if needed. If it isn't
-         * configured, then it cannot be supported.
-         */
-        if (state == PM_SUSPEND_DISK)
-#ifdef CONFIG_SOFTWARE_SUSPEND
-                return 1;
-#else
-                return 0;
-#endif
-
-        /* all other states need lowlevel support and need to be
-         * valid to the lowlevel implementation, no valid callback
+        /* All states need lowlevel support and need to be valid
+         * to the lowlevel implementation, no valid callback
          * implies that none are valid. */
         if (!pm_ops || !pm_ops->valid || !pm_ops->valid(state))
                 return 0;
@@ -229,11 +212,6 @@ static int enter_state(suspend_state_t state)
         if (!mutex_trylock(&pm_mutex))
                 return -EBUSY;
 
-        if (state == PM_SUSPEND_DISK) {
-                error = pm_suspend_disk();
-                goto Unlock;
-        }
-
         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
         if ((error = suspend_prepare(state)))
                 goto Unlock;
@@ -251,7 +229,7 @@ static int enter_state(suspend_state_t state)
 
 /**
  *      pm_suspend - Externally visible function for suspending system.
- *      @state:         Enumarted value of state to enter.
+ *      @state:         Enumerated value of state to enter.
  *
  *      Determine whether or not value is within range, get state 
  *      structure, and enter (above).
@@ -289,7 +267,13 @@ static ssize_t state_show(struct kset *kset, char *buf)
                 if (pm_states[i] && valid_state(i))
                         s += sprintf(s,"%s ", pm_states[i]);
         }
-        s += sprintf(s,"\n");
+#ifdef CONFIG_SOFTWARE_SUSPEND
+        s += sprintf(s, "%s\n", "disk");
+#else
+        if (s != buf)
+                /* convert the last space to a newline */
+                *(s-1) = '\n';
+#endif
         return (s - buf);
 }
 
@@ -304,6 +288,12 @@ static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
         p = memchr(buf, '\n', n);
         len = p ? p - buf : n;
 
+        /* First, check if we are requested to hibernate */
+        if (!strncmp(buf, "disk", len)) {
+                error = hibernate();
+                return error ? error : n;
+        }
+
         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
                 if (*s && !strncmp(buf, *s, len))
                         break;