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 dcd165f92a88..ebdd7f55273d 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 278946aecaf0..444cea80fde8 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);