Merge branch 'pm-freezer' into pm-sleep

* pm-freezer: (26 commits)
  Freezer / sunrpc / NFS: don't allow TASK_KILLABLE sleeps to block the freezer
  Freezer: fix more fallout from the thaw_process rename
  freezer: fix wait_event_freezable/__thaw_task races
  freezer: kill unused set_freezable_with_signal()
  dmatest: don't use set_freezable_with_signal()
  usb_storage: don't use set_freezable_with_signal()
  freezer: remove unused @sig_only from freeze_task()
  freezer: use lock_task_sighand() in fake_signal_wake_up()
  freezer: restructure __refrigerator()
  freezer: fix set_freezable[_with_signal]() race
  freezer: remove should_send_signal() and update frozen()
  freezer: remove now unused TIF_FREEZE
  freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE
  cgroup_freezer: prepare for removal of TIF_FREEZE
  freezer: clean up freeze_processes() failure path
  freezer: kill PF_FREEZING
  freezer: test freezable conditions while holding freezer_lock
  freezer: make freezing indicate freeze condition in effect
  freezer: use dedicated lock instead of task_lock() + memory barrier
  freezer: don't distinguish nosig tasks on thaw
  ...

4 files changed, 37 insertions, 67 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 5314a94a92c1..605149a6d219 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -590,17 +590,6 @@ static void power_down(void)
         while(1);
 }
 
-static int prepare_processes(void)
-{
-        int error = 0;
-
-        if (freeze_processes()) {
-                error = -EBUSY;
-                thaw_processes();
-        }
-        return error;
-}
-
 /**
  * hibernate - Carry out system hibernation, including saving the image.
  */
@@ -633,7 +622,7 @@ int hibernate(void)
         sys_sync();
         printk("done.\n");
 
-        error = prepare_processes();
+        error = freeze_processes();
         if (error)
                 goto Finish;
 
@@ -796,7 +785,7 @@ static int software_resume(void)
         }
 
         pr_debug("PM: Preparing processes for restore.\n");
-        error = prepare_processes();
+        error = freeze_processes();
         if (error) {
                 swsusp_close(FMODE_READ);
                 goto Done;
diff --git a/kernel/power/process.c b/kernel/power/process.c
index addbbe5531bc..77274c9ba2f1 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -22,16 +22,7 @@
  */
 #define TIMEOUT (20 * HZ)
 
-static inline int freezable(struct task_struct * p)
-{
-        if ((p == current) ||
-            (p->flags & PF_NOFREEZE) ||
-            (p->exit_state != 0))
-                return 0;
-        return 1;
-}
-
-static int try_to_freeze_tasks(bool sig_only)
+static int try_to_freeze_tasks(bool user_only)
 {
         struct task_struct *g, *p;
         unsigned long end_time;
@@ -46,17 +37,14 @@ static int try_to_freeze_tasks(bool sig_only)
 
         end_time = jiffies + TIMEOUT;
 
-        if (!sig_only)
+        if (!user_only)
                 freeze_workqueues_begin();
 
         while (true) {
                 todo = 0;
                 read_lock(&tasklist_lock);
                 do_each_thread(g, p) {
-                        if (frozen(p) || !freezable(p))
-                                continue;
-
-                        if (!freeze_task(p, sig_only))
+                        if (p == current || !freeze_task(p))
                                 continue;
 
                         /*
@@ -77,7 +65,7 @@ static int try_to_freeze_tasks(bool sig_only)
                 } while_each_thread(g, p);
                 read_unlock(&tasklist_lock);
 
-                if (!sig_only) {
+                if (!user_only) {
                         wq_busy = freeze_workqueues_busy();
                         todo += wq_busy;
                 }
@@ -103,11 +91,6 @@ static int try_to_freeze_tasks(bool sig_only)
         elapsed_csecs = elapsed_csecs64;
 
         if (todo) {
-                /* This does not unfreeze processes that are already frozen
-                 * (we have slightly ugly calling convention in that respect,
-                 * and caller must call thaw_processes() if something fails),
-                 * but it cleans up leftover PF_FREEZE requests.
-                 */
                 printk("\n");
                 printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds "
                        "(%d tasks refusing to freeze, wq_busy=%d):\n",
@@ -115,15 +98,11 @@ static int try_to_freeze_tasks(bool sig_only)
                        elapsed_csecs / 100, elapsed_csecs % 100,
                        todo - wq_busy, wq_busy);
 
-                thaw_workqueues();
-
                 read_lock(&tasklist_lock);
                 do_each_thread(g, p) {
-                        task_lock(p);
-                        if (!wakeup && freezing(p) && !freezer_should_skip(p))
+                        if (!wakeup && !freezer_should_skip(p) &&
+                            p != current && freezing(p) && !frozen(p))
                                 sched_show_task(p);
-                        cancel_freezing(p);
-                        task_unlock(p);
                 } while_each_thread(g, p);
                 read_unlock(&tasklist_lock);
         } else {
@@ -136,12 +115,18 @@ static int try_to_freeze_tasks(bool sig_only)
 
 /**
  * freeze_processes - Signal user space processes to enter the refrigerator.
+ *
+ * On success, returns 0.  On failure, -errno and system is fully thawed.
  */
 int freeze_processes(void)
 {
         int error;
 
+        if (!pm_freezing)
+                atomic_inc(&system_freezing_cnt);
+
         printk("Freezing user space processes ... ");
+        pm_freezing = true;
         error = try_to_freeze_tasks(true);
         if (!error) {
                 printk("done.");
@@ -150,17 +135,22 @@ int freeze_processes(void)
         printk("\n");
         BUG_ON(in_atomic());
 
+        if (error)
+                thaw_processes();
         return error;
 }
 
 /**
  * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
+ *
+ * On success, returns 0.  On failure, -errno and system is fully thawed.
  */
 int freeze_kernel_threads(void)
 {
         int error;
 
         printk("Freezing remaining freezable tasks ... ");
+        pm_nosig_freezing = true;
         error = try_to_freeze_tasks(false);
         if (!error)
                 printk("done.");
@@ -168,37 +158,32 @@ int freeze_kernel_threads(void)
         printk("\n");
         BUG_ON(in_atomic());
 
+        if (error)
+                thaw_processes();
         return error;
 }
 
-static void thaw_tasks(bool nosig_only)
+void thaw_processes(void)
 {
         struct task_struct *g, *p;
 
-        read_lock(&tasklist_lock);
-        do_each_thread(g, p) {
-                if (!freezable(p))
-                        continue;
+        if (pm_freezing)
+                atomic_dec(&system_freezing_cnt);
+        pm_freezing = false;
+        pm_nosig_freezing = false;
 
-                if (nosig_only && should_send_signal(p))
-                        continue;
+        oom_killer_enable();
+
+        printk("Restarting tasks ... ");
 
-                if (cgroup_freezing_or_frozen(p))
-                        continue;
+        thaw_workqueues();
 
-                thaw_process(p);
+        read_lock(&tasklist_lock);
+        do_each_thread(g, p) {
+                __thaw_task(p);
         } while_each_thread(g, p);
         read_unlock(&tasklist_lock);
-}
 
-void thaw_processes(void)
-{
-        oom_killer_enable();
-
-        printk("Restarting tasks ... ");
-        thaw_workqueues();
-        thaw_tasks(true);
-        thaw_tasks(false);
         schedule();
         printk("done.\n");
 }
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4953dc054c53..d336b27d1104 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -106,13 +106,11 @@ static int suspend_prepare(void)
                 goto Finish;
 
         error = suspend_freeze_processes();
-        if (error) {
-                suspend_stats.failed_freeze++;
-                dpm_save_failed_step(SUSPEND_FREEZE);
-        } else
+        if (!error)
                 return 0;
 
-        suspend_thaw_processes();
+        suspend_stats.failed_freeze++;
+        dpm_save_failed_step(SUSPEND_FREEZE);
         usermodehelper_enable();
  Finish:
         pm_notifier_call_chain(PM_POST_SUSPEND);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index e2aff0fc2697..c202e2e1a2d5 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -257,10 +257,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                         break;
 
                 error = freeze_processes();
-                if (error) {
-                        thaw_processes();
+                if (error)
                         usermodehelper_enable();
-                }
                 if (!error)
                         data->frozen = 1;
                 break;