[PATCH] suspend/resume SMP support

Using CPU hotplug to support suspend/resume SMP.  Both S3 and S4 use
disable/enable_nonboot_cpus API.  The S4 part is based on Pavel's original S4
SMP patch.

Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 6 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 4cdebc972ff2..c94cb9e95090 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -55,6 +55,13 @@ static int suspend_prepare(suspend_state_t state)
 
         pm_prepare_console();
 
+        disable_nonboot_cpus();
+
+        if (num_online_cpus() != 1) {
+                error = -EPERM;
+                goto Enable_cpu;
+        }
+
         if (freeze_processes()) {
                 error = -EAGAIN;
                 goto Thaw;
@@ -75,6 +82,8 @@ static int suspend_prepare(suspend_state_t state)
                 pm_ops->finish(state);
  Thaw:
         thaw_processes();
+ Enable_cpu:
+        enable_nonboot_cpus();
         pm_restore_console();
         return error;
 }
@@ -113,6 +122,7 @@ static void suspend_finish(suspend_state_t state)
         if (pm_ops && pm_ops->finish)
                 pm_ops->finish(state);
         thaw_processes();
+        enable_nonboot_cpus();
         pm_restore_console();
 }
 
@@ -150,12 +160,6 @@ static int enter_state(suspend_state_t state)
                 goto Unlock;
         }
 
-        /* Suspend is hard to get right on SMP. */
-        if (num_online_cpus() != 1) {
-                error = -EPERM;
-                goto Unlock;
-        }
-
         pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
         if ((error = suspend_prepare(state)))
                 goto Unlock;