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
Signed-off-by: Matt Helsley
Acked-by: Serge E. Hallyn
Tested-by: Matt Helsley
---
include/linux/freezer.h | 24 +++++----
kernel/Makefile | 2 +-
kernel/freezer.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/power/process.c | 116 --------------------------------------------
4 files changed, 136 insertions(+), 128 deletions(-)
create mode 100644 kernel/freezer.c

diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index deddeed..4081768 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -6,7 +6,6 @@
#include
#include

-#ifdef CONFIG_PM_SLEEP
/*
* Check if a process has been frozen
*/
@@ -39,6 +38,11 @@ static inline void clear_freeze_flag(struct task_struct *p)
clear_tsk_thread_flag(p, TIF_FREEZE);
}

+static inline bool should_send_signal(struct task_struct *p)
+{
+ return !(p->flags & PF_FREEZER_NOSIG);
+}
+
/*
* Wake up a frozen process
*
@@ -63,8 +67,6 @@ static inline int thaw_process(struct task_struct *p)
}

extern void refrigerator(void);
-extern int freeze_processes(void);
-extern void thaw_processes(void);

static inline int try_to_freeze(void)
{
@@ -75,6 +77,14 @@ static inline int try_to_freeze(void)
return 0;
}

+extern bool freeze_task(struct task_struct *p, bool sig_only);
+extern void cancel_freezing(struct task_struct *p);
+
+#ifdef CONFIG_PM_SLEEP
+
+extern int freeze_processes(void);
+extern void thaw_processes(void);
+
/*
* The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
* calls wait_for_completion(&vfork) and reset right after it returns from this
@@ -167,18 +177,10 @@ static inline void set_freezable_with_signal(void)
__retval; \
})
#else /* !CONFIG_PM_SLEEP */
-static inline int frozen(struct task_struct *p) { return 0; }
-static inline int freezing(struct task_struct *p) { return 0; }
-static inline void set_freeze_flag(struct task_struct *p) {}
-static inline void clear_freeze_flag(struct task_struct *p) {}
-static inline int thaw_process(struct task_struct *p) { return 1; }

-static inline void refrigerator(void) {}
static inline int freeze_processes(void) { BUG(); return 0; }
static inline void thaw_processes(void) {}

-static inline int try_to_freeze(void) { return 0; }
-
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; }
diff --git a/kernel/Makefile b/kernel/Makefile
index 4e1d7df..9844f47 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -5,7 +5,7 @@
obj-y = sched.o fork.o exec_domain.o panic.o printk.o \
cpu.o exit.o itimer.o time.o softirq.o resource.o \
sysctl.o capability.o ptrace.o timer.o user.o \
- signal.o sys.o kmod.o workqueue.o pid.o \
+ signal.o sys.o kmod.o workqueue.o pid.o freezer.o \
rcupdate.o extable.o params.o posix-timers.o \
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
diff --git a/kernel/freezer.c b/kernel/freezer.c
new file mode 100644
index 0000000..cb0931f
--- /dev/null
+++ b/kernel/freezer.c
@@ -0,0 +1,122 @@
+/*
+ * kernel/freezer.c - Function to freeze a process
+ *
+ * Originally from kernel/power/process.c
+ */
+
+#include
+#include
+#include
+#include
+#include
+
+/*
+ * 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);
+}
+EXPORT_SYMBOL(refrigerator);
+
+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);
+}
+
+/**
+ * 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.
+ */
+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;
+}
+
+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);
+ }
+}
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 278946a..444cea8 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);
--
1.5.3.7

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