container freezer: make refrigerator always available

Now that the TIF_FREEZE flag is available in all architectures, extract
the refrigerator() and freeze_task() from kernel/power/process.c and make
it available to all.

The refrigerator() can now be used in a control group subsystem
implementing a control group freezer.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 116 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index dcd165f92a8..ebdd7f55273 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -85,6 +85,9 @@ config PM_SLEEP
 	depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
 	default y
 
+config FREEZER
+	def_bool PM_SLEEP
+
 config SUSPEND
 	bool "Suspend to RAM and standby"
 	depends on PM && ARCH_SUSPEND_POSSIBLE
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 278946aecaf..444cea80fde 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -28,121 +28,6 @@ static inline int freezeable(struct task_struct * p)
 	return 1;
 }
 
-/*
- * freezing is complete, mark current process as frozen
- */
-static inline void frozen_process(void)
-{
-	if (!unlikely(current->flags & PF_NOFREEZE)) {
-		current->flags |= PF_FROZEN;
-		wmb();
-	}
-	clear_freeze_flag(current);
-}
-
-/* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(void)
-{
-	/* Hmm, should we be allowed to suspend when there are realtime
-	   processes around? */
-	long save;
-
-	task_lock(current);
-	if (freezing(current)) {
-		frozen_process();
-		task_unlock(current);
-	} else {
-		task_unlock(current);
-		return;
-	}
-	save = current->state;
-	pr_debug("%s entered refrigerator\n", current->comm);
-
-	spin_lock_irq(&current->sighand->siglock);
-	recalc_sigpending(); /* We sent fake signal, clean it up */
-	spin_unlock_irq(&current->sighand->siglock);
-
-	for (;;) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		if (!frozen(current))
-			break;
-		schedule();
-	}
-	pr_debug("%s left refrigerator\n", current->comm);
-	__set_current_state(save);
-}
-
-static void fake_signal_wake_up(struct task_struct *p)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&p->sighand->siglock, flags);
-	signal_wake_up(p, 0);
-	spin_unlock_irqrestore(&p->sighand->siglock, flags);
-}
-
-static inline bool should_send_signal(struct task_struct *p)
-{
-	return !(p->flags & PF_FREEZER_NOSIG);
-}
-
-/**
- *	freeze_task - send a freeze request to given task
- *	@p: task to send the request to
- *	@sig_only: if set, the request will only be sent if the task has the
- *		PF_FREEZER_NOSIG flag unset
- *	Return value: 'false', if @sig_only is set and the task has
- *		PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
- *
- *	The freeze request is sent by setting the tasks's TIF_FREEZE flag and
- *	either sending a fake signal to it or waking it up, depending on whether
- *	or not it has PF_FREEZER_NOSIG set.  If @sig_only is set and the task
- *	has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
- *	TIF_FREEZE flag will not be set.
- */
-static bool freeze_task(struct task_struct *p, bool sig_only)
-{
-	/*
-	 * We first check if the task is freezing and next if it has already
-	 * been frozen to avoid the race with frozen_process() which first marks
-	 * the task as frozen and next clears its TIF_FREEZE.
-	 */
-	if (!freezing(p)) {
-		rmb();
-		if (frozen(p))
-			return false;
-
-		if (!sig_only || should_send_signal(p))
-			set_freeze_flag(p);
-		else
-			return false;
-	}
-
-	if (should_send_signal(p)) {
-		if (!signal_pending(p))
-			fake_signal_wake_up(p);
-	} else if (sig_only) {
-		return false;
-	} else {
-		wake_up_state(p, TASK_INTERRUPTIBLE);
-	}
-
-	return true;
-}
-
-static void cancel_freezing(struct task_struct *p)
-{
-	unsigned long flags;
-
-	if (freezing(p)) {
-		pr_debug("  clean up: %s\n", p->comm);
-		clear_freeze_flag(p);
-		spin_lock_irqsave(&p->sighand->siglock, flags);
-		recalc_sigpending_and_wake(p);
-		spin_unlock_irqrestore(&p->sighand->siglock, flags);
-	}
-}
-
 static int try_to_freeze_tasks(bool sig_only)
 {
 	struct task_struct *g, *p;
@@ -264,4 +149,3 @@ void thaw_processes(void)
 	printk("done.\n");
 }
 
-EXPORT_SYMBOL(refrigerator);