From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Mon, 14 Nov 2011 02:06:38 +0000 (+1100)
Subject: Revert "freezer: kill unused set_freezable_with_signal()"
X-Git-Tag: next-20111114~15
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=abca3a7ffc8fb69cbed2c814cec21e67a37c43dd;p=karo-tx-linux.git

Revert "freezer: kill unused set_freezable_with_signal()"

This reverts commit cd3bc8fbc2d55ae0918184fb34992054dc4eb710.
---

diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 09570ac22be6..cc779bb9cd74 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -49,7 +49,7 @@ static inline bool try_to_freeze(void)
 }
 
 extern bool freeze_task(struct task_struct *p);
-extern bool set_freezable(void);
+extern bool __set_freezable(bool with_signal);
 
 #ifdef CONFIG_CGROUP_FREEZER
 extern bool cgroup_freezing(struct task_struct *task);
@@ -104,6 +104,23 @@ static inline int freezer_should_skip(struct task_struct *p)
 	return !!(p->flags & PF_FREEZER_SKIP);
 }
 
+/*
+ * Tell the freezer that the current task should be frozen by it
+ */
+static inline bool set_freezable(void)
+{
+	return __set_freezable(false);
+}
+
+/*
+ * Tell the freezer that the current task should be frozen by it and that it
+ * should send a fake signal to the task to freeze it.
+ */
+static inline bool set_freezable_with_signal(void)
+{
+	return __set_freezable(true);
+}
+
 /*
  * Freezer-friendly wrappers around wait_event_interruptible(),
  * wait_event_killable() and wait_event_interruptible_timeout(), originally
@@ -161,6 +178,7 @@ static inline void freezer_do_not_count(void) {}
 static inline void freezer_count(void) {}
 static inline int freezer_should_skip(struct task_struct *p) { return 0; }
 static inline void set_freezable(void) {}
+static inline void set_freezable_with_signal(void) {}
 
 #define wait_event_freezable(wq, condition)				\
 		wait_event_interruptible(wq, condition)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 35718ff31600..5e5734ee37af 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1788,6 +1788,7 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define PF_MEMPOLICY	0x10000000	/* Non-default NUMA mempolicy */
 #define PF_MUTEX_TESTER	0x20000000	/* Thread belongs to the rt mutex tester */
 #define PF_FREEZER_SKIP	0x40000000	/* Freezer should not count it as freezable */
+#define PF_FREEZER_NOSIG 0x80000000	/* Freezer won't send signals to it */
 
 /*
  * Only the _current_ task can read/write to tsk->flags, but other
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 9815b8d1eed5..2589a61de44c 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -39,7 +39,7 @@ bool freezing_slow_path(struct task_struct *p)
 	if (pm_nosig_freezing || cgroup_freezing(p))
 		return true;
 
-	if (pm_freezing && !(p->flags & PF_KTHREAD))
+	if (pm_freezing && !(p->flags & PF_FREEZER_NOSIG))
 		return true;
 
 	return false;
@@ -72,6 +72,10 @@ bool __refrigerator(bool check_kthr_stop)
 		schedule();
 	}
 
+	spin_lock_irq(&current->sighand->siglock);
+	recalc_sigpending(); /* We sent fake signal, clean it up */
+	spin_unlock_irq(&current->sighand->siglock);
+
 	pr_debug("%s left refrigerator\n", current->comm);
 
 	/*
@@ -116,7 +120,7 @@ bool freeze_task(struct task_struct *p)
 		return false;
 	}
 
-	if (!(p->flags & PF_KTHREAD)) {
+	if (!(p->flags & PF_FREEZER_NOSIG)) {
 		fake_signal_wake_up(p);
 		/*
 		 * fake_signal_wake_up() goes through p's scheduler
@@ -141,19 +145,28 @@ void __thaw_task(struct task_struct *p)
 	 * be visible to @p as waking up implies wmb.  Waking up inside
 	 * freezer_lock also prevents wakeups from leaking outside
 	 * refrigerator.
+	 *
+	 * If !FROZEN, @p hasn't reached refrigerator, recalc sigpending to
+	 * avoid leaving dangling TIF_SIGPENDING behind.
 	 */
 	spin_lock_irqsave(&freezer_lock, flags);
-	if (frozen(p))
+	if (frozen(p)) {
 		wake_up_process(p);
+	} else {
+		spin_lock(&p->sighand->siglock);
+		recalc_sigpending_and_wake(p);
+		spin_unlock(&p->sighand->siglock);
+	}
 	spin_unlock_irqrestore(&freezer_lock, flags);
 }
 
 /**
- * set_freezable - make %current freezable
+ * __set_freezable - make %current freezable
+ * @with_signal: do we want %TIF_SIGPENDING for notification too?
  *
  * Mark %current freezable and enter refrigerator if necessary.
  */
-bool set_freezable(void)
+bool __set_freezable(bool with_signal)
 {
 	might_sleep();
 
@@ -164,8 +177,10 @@ bool set_freezable(void)
 	 */
 	spin_lock_irq(&freezer_lock);
 	current->flags &= ~PF_NOFREEZE;
+	if (with_signal)
+		current->flags &= ~PF_FREEZER_NOSIG;
 	spin_unlock_irq(&freezer_lock);
 
 	return try_to_freeze();
 }
-EXPORT_SYMBOL(set_freezable);
+EXPORT_SYMBOL(__set_freezable);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 3d3de633702e..1c36deaae2f1 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -282,7 +282,7 @@ int kthreadd(void *unused)
 	set_cpus_allowed_ptr(tsk, cpu_all_mask);
 	set_mems_allowed(node_states[N_HIGH_MEMORY]);
 
-	current->flags |= PF_NOFREEZE;
+	current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;
 
 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);