1 files changed, 301 insertions, 0 deletions
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
new file mode 100644
index 000000000..6b7fd9cf5
--- /dev/null
+++ b/include/linux/freezer.h
@@ -0,0 +1,301 @@
+/* Freezer declarations */
+
+#ifndef FREEZER_H_INCLUDED
+#define FREEZER_H_INCLUDED
+
+#include <linux/debug_locks.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/atomic.h>
+
+#ifdef CONFIG_FREEZER
+extern atomic_t system_freezing_cnt;	/* nr of freezing conds in effect */
+extern bool pm_freezing;		/* PM freezing in effect */
+extern bool pm_nosig_freezing;		/* PM nosig freezing in effect */
+
+/*
+ * Timeout for stopping processes
+ */
+extern unsigned int freeze_timeout_msecs;
+
+/*
+ * Check if a process has been frozen
+ */
+static inline bool frozen(struct task_struct *p)
+{
+	return p->flags & PF_FROZEN;
+}
+
+extern bool freezing_slow_path(struct task_struct *p);
+
+/*
+ * Check if there is a request to freeze a process
+ */
+static inline bool freezing(struct task_struct *p)
+{
+	if (likely(!atomic_read(&system_freezing_cnt)))
+		return false;
+	return freezing_slow_path(p);
+}
+
+/* Takes and releases task alloc lock using task_lock() */
+extern void __thaw_task(struct task_struct *t);
+
+extern bool __refrigerator(bool check_kthr_stop);
+extern int freeze_processes(void);
+extern int freeze_kernel_threads(void);
+extern void thaw_processes(void);
+extern void thaw_kernel_threads(void);
+
+/*
+ * DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION
+ * If try_to_freeze causes a lockdep warning it means the caller may deadlock
+ */
+static inline bool try_to_freeze_unsafe(void)
+{
+	might_sleep();
+	if (likely(!freezing(current)))
+		return false;
+	return __refrigerator(false);
+}
+
+static inline bool try_to_freeze(void)
+{
+	if (!(current->flags & PF_NOFREEZE))
+		debug_check_no_locks_held();
+	return try_to_freeze_unsafe();
+}
+
+extern bool freeze_task(struct task_struct *p);
+extern bool set_freezable(void);
+
+#ifdef CONFIG_CGROUP_FREEZER
+extern bool cgroup_freezing(struct task_struct *task);
+#else /* !CONFIG_CGROUP_FREEZER */
+static inline bool cgroup_freezing(struct task_struct *task)
+{
+	return false;
+}
+#endif /* !CONFIG_CGROUP_FREEZER */
+
+/*
+ * 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
+ * function.  Next, the parent should call try_to_freeze() to freeze itself
+ * appropriately in case the child has exited before the freezing of tasks is
+ * complete.  However, we don't want kernel threads to be frozen in unexpected
+ * places, so we allow them to block freeze_processes() instead or to set
+ * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the
+ * parent won't really block freeze_processes(), since ____call_usermodehelper()
+ * (the child) does a little before exec/exit and it can't be frozen before
+ * waking up the parent.
+ */
+
+
+/**
+ * freezer_do_not_count - tell freezer to ignore %current
+ *
+ * Tell freezers to ignore the current task when determining whether the
+ * target frozen state is reached.  IOW, the current task will be
+ * considered frozen enough by freezers.
+ *
+ * The caller shouldn't do anything which isn't allowed for a frozen task
+ * until freezer_cont() is called.  Usually, freezer[_do_not]_count() pair
+ * wrap a scheduling operation and nothing much else.
+ */
+static inline void freezer_do_not_count(void)
+{
+	current->flags |= PF_FREEZER_SKIP;
+}
+
+/**
+ * freezer_count - tell freezer to stop ignoring %current
+ *
+ * Undo freezer_do_not_count().  It tells freezers that %current should be
+ * considered again and tries to freeze if freezing condition is already in
+ * effect.
+ */
+static inline void freezer_count(void)
+{
+	current->flags &= ~PF_FREEZER_SKIP;
+	/*
+	 * If freezing is in progress, the following paired with smp_mb()
+	 * in freezer_should_skip() ensures that either we see %true
+	 * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP.
+	 */
+	smp_mb();
+	try_to_freeze();
+}
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline void freezer_count_unsafe(void)
+{
+	current->flags &= ~PF_FREEZER_SKIP;
+	smp_mb();
+	try_to_freeze_unsafe();
+}
+
+/**
+ * freezer_should_skip - whether to skip a task when determining frozen
+ *			 state is reached
+ * @p: task in quesion
+ *
+ * This function is used by freezers after establishing %true freezing() to
+ * test whether a task should be skipped when determining the target frozen
+ * state is reached.  IOW, if this function returns %true, @p is considered
+ * frozen enough.
+ */
+static inline bool freezer_should_skip(struct task_struct *p)
+{
+	/*
+	 * The following smp_mb() paired with the one in freezer_count()
+	 * ensures that either freezer_count() sees %true freezing() or we
+	 * see cleared %PF_FREEZER_SKIP and return %false.  This makes it
+	 * impossible for a task to slip frozen state testing after
+	 * clearing %PF_FREEZER_SKIP.
+	 */
+	smp_mb();
+	return p->flags & PF_FREEZER_SKIP;
+}
+
+/*
+ * These functions are intended to be used whenever you want allow a sleeping
+ * task to be frozen. Note that neither return any clear indication of
+ * whether a freeze event happened while in this function.
+ */
+
+/* Like schedule(), but should not block the freezer. */
+static inline void freezable_schedule(void)
+{
+	freezer_do_not_count();
+	schedule();
+	freezer_count();
+}
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline void freezable_schedule_unsafe(void)
+{
+	freezer_do_not_count();
+	schedule();
+	freezer_count_unsafe();
+}
+
+/*
+ * Like freezable_schedule_timeout(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline long freezable_schedule_timeout(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout(timeout);
+	freezer_count();
+	return __retval;
+}
+
+/*
+ * Like schedule_timeout_interruptible(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline long freezable_schedule_timeout_interruptible(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_interruptible(timeout);
+	freezer_count();
+	return __retval;
+}
+
+/* Like schedule_timeout_killable(), but should not block the freezer. */
+static inline long freezable_schedule_timeout_killable(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_killable(timeout);
+	freezer_count();
+	return __retval;
+}
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline long freezable_schedule_timeout_killable_unsafe(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_killable(timeout);
+	freezer_count_unsafe();
+	return __retval;
+}
+
+/*
+ * Like schedule_hrtimeout_range(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline int freezable_schedule_hrtimeout_range(ktime_t *expires,
+		unsigned long delta, const enum hrtimer_mode mode)
+{
+	int __retval;
+	freezer_do_not_count();
+	__retval = schedule_hrtimeout_range(expires, delta, mode);
+	freezer_count();
+	return __retval;
+}
+
+/*
+ * Freezer-friendly wrappers around wait_event_interruptible(),
+ * wait_event_killable() and wait_event_interruptible_timeout(), originally
+ * defined in <linux/wait.h>
+ */
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+#define wait_event_freezekillable_unsafe(wq, condition)			\
+({									\
+	int __retval;							\
+	freezer_do_not_count();						\
+	__retval = wait_event_killable(wq, (condition));		\
+	freezer_count_unsafe();						\
+	__retval;							\
+})
+
+#else /* !CONFIG_FREEZER */
+static inline bool frozen(struct task_struct *p) { return false; }
+static inline bool freezing(struct task_struct *p) { return false; }
+static inline void __thaw_task(struct task_struct *t) {}
+
+static inline bool __refrigerator(bool check_kthr_stop) { return false; }
+static inline int freeze_processes(void) { return -ENOSYS; }
+static inline int freeze_kernel_threads(void) { return -ENOSYS; }
+static inline void thaw_processes(void) {}
+static inline void thaw_kernel_threads(void) {}
+
+static inline bool try_to_freeze_nowarn(void) { return false; }
+static inline bool try_to_freeze(void) { return false; }
+
+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) {}
+
+#define freezable_schedule()  schedule()
+
+#define freezable_schedule_unsafe()  schedule()
+
+#define freezable_schedule_timeout(timeout)  schedule_timeout(timeout)
+
+#define freezable_schedule_timeout_interruptible(timeout)		\
+	schedule_timeout_interruptible(timeout)
+
+#define freezable_schedule_timeout_killable(timeout)			\
+	schedule_timeout_killable(timeout)
+
+#define freezable_schedule_timeout_killable_unsafe(timeout)		\
+	schedule_timeout_killable(timeout)
+
+#define freezable_schedule_hrtimeout_range(expires, delta, mode)	\
+	schedule_hrtimeout_range(expires, delta, mode)
+
+#define wait_event_freezekillable_unsafe(wq, condition)			\
+		wait_event_killable(wq, condition)
+
+#endif /* !CONFIG_FREEZER */
+
+#endif	/* FREEZER_H_INCLUDED */