Merge tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Power management fixes for 3.3-rc3

Three power management regression fixes, one for a recent regression introcuded
by the freezer changes during the 3.3 merge window and two for regressions
in cpuidle (resulting from PM QoS changes) and in the hibernate user space
interface, both introduced during the 3.2 development cycle.

They include:

* Two hibernate (s2disk) regression fixes from Srivatsa S. Bhat (for
 regressions introduced during the 3.3 merge window and during the 3.2
 development cycle).

* A cpuidle fix from Venki Pallipadi for a regression resulting from PM QoS
 changes during the 3.2 development cycle causing cpuidle to work incorrectly
 for CONFIG_PM unset.

* tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / QoS: CPU C-state breakage with PM Qos change
  PM / Freezer: Thaw only kernel threads if freezing of kernel threads fails
  PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl path

3 files changed, 31 insertions, 6 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index 0c4defe6d3b8..21724eee5206 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -231,8 +231,28 @@ extern int pm_test_level;
 #ifdef CONFIG_SUSPEND_FREEZER
 static inline int suspend_freeze_processes(void)
 {
-        int error = freeze_processes();
-        return error ? : freeze_kernel_threads();
+        int error;
+
+        error = freeze_processes();
+
+        /*
+         * freeze_processes() automatically thaws every task if freezing
+         * fails. So we need not do anything extra upon error.
+         */
+        if (error)
+                goto Finish;
+
+        error = freeze_kernel_threads();
+
+        /*
+         * freeze_kernel_threads() thaws only kernel threads upon freezing
+         * failure. So we have to thaw the userspace tasks ourselves.
+         */
+        if (error)
+                thaw_processes();
+
+ Finish:
+        return error;
 }
 
 static inline void suspend_thaw_processes(void)
diff --git a/kernel/power/process.c b/kernel/power/process.c
index eeca00311f39..7e426459e60a 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -143,7 +143,10 @@ int freeze_processes(void)
 /**
  * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
  *
- * On success, returns 0.  On failure, -errno and system is fully thawed.
+ * On success, returns 0.  On failure, -errno and only the kernel threads are
+ * thawed, so as to give a chance to the caller to do additional cleanups
+ * (if any) before thawing the userspace tasks. So, it is the responsibility
+ * of the caller to thaw the userspace tasks, when the time is right.
  */
 int freeze_kernel_threads(void)
 {
@@ -159,7 +162,7 @@ int freeze_kernel_threads(void)
         BUG_ON(in_atomic());
 
         if (error)
-                thaw_processes();
+                thaw_kernel_threads();
         return error;
 }
 
diff --git a/kernel/power/user.c b/kernel/power/user.c
index e5a21a857302..3e100075b13c 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -249,13 +249,15 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                 }
                 pm_restore_gfp_mask();
                 error = hibernation_snapshot(data->platform_support);
-                if (!error) {
+                if (error) {
+                        thaw_kernel_threads();
+                } else {
                         error = put_user(in_suspend, (int __user *)arg);
                         if (!error && !freezer_test_done)
                                 data->ready = 1;
                         if (freezer_test_done) {
                                 freezer_test_done = false;
-                                thaw_processes();
+                                thaw_kernel_threads();
                         }
                 }
                 break;