summaryrefslogtreecommitdiffstats
path: root/kernel/include/linux/freezer.h
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/include/linux/freezer.h')
-rw-r--r--kernel/include/linux/freezer.h301
1 files changed, 301 insertions, 0 deletions
diff --git a/kernel/include/linux/freezer.h b/kernel/include/linux/freezer.h
new file mode 100644
index 000000000..6b7fd9cf5
--- /dev/null
+++ b/kernel/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 */