1 /* Freezer declarations */
3 #ifndef FREEZER_H_INCLUDED
4 #define FREEZER_H_INCLUDED
6 #include <linux/sched.h>
7 #include <linux/wait.h>
8 #include <linux/atomic.h>
11 extern atomic_t system_freezing_cnt; /* nr of freezing conds in effect */
12 extern bool pm_freezing; /* PM freezing in effect */
13 extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
16 * Check if a process has been frozen
18 static inline bool frozen(struct task_struct *p)
20 return p->flags & PF_FROZEN;
23 extern bool freezing_slow_path(struct task_struct *p);
26 * Check if there is a request to freeze a process
28 static inline bool freezing(struct task_struct *p)
30 if (likely(!atomic_read(&system_freezing_cnt)))
32 return freezing_slow_path(p);
35 /* Takes and releases task alloc lock using task_lock() */
36 extern void __thaw_task(struct task_struct *t);
38 extern bool __refrigerator(bool check_kthr_stop);
39 extern int freeze_processes(void);
40 extern int freeze_kernel_threads(void);
41 extern void thaw_processes(void);
43 static inline bool try_to_freeze(void)
46 if (likely(!freezing(current)))
48 return __refrigerator(false);
51 extern bool freeze_task(struct task_struct *p);
52 extern bool set_freezable(void);
54 #ifdef CONFIG_CGROUP_FREEZER
55 extern bool cgroup_freezing(struct task_struct *task);
56 #else /* !CONFIG_CGROUP_FREEZER */
57 static inline bool cgroup_freezing(struct task_struct *task)
61 #endif /* !CONFIG_CGROUP_FREEZER */
64 * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
65 * calls wait_for_completion(&vfork) and reset right after it returns from this
66 * function. Next, the parent should call try_to_freeze() to freeze itself
67 * appropriately in case the child has exited before the freezing of tasks is
68 * complete. However, we don't want kernel threads to be frozen in unexpected
69 * places, so we allow them to block freeze_processes() instead or to set
70 * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the
71 * parent won't really block freeze_processes(), since ____call_usermodehelper()
72 * (the child) does a little before exec/exit and it can't be frozen before
73 * waking up the parent.
77 /* Tell the freezer not to count the current task as freezable. */
78 static inline void freezer_do_not_count(void)
80 current->flags |= PF_FREEZER_SKIP;
84 * Tell the freezer to count the current task as freezable again and try to
87 static inline void freezer_count(void)
89 current->flags &= ~PF_FREEZER_SKIP;
94 * Check if the task should be counted as freezable by the freezer
96 static inline int freezer_should_skip(struct task_struct *p)
98 return !!(p->flags & PF_FREEZER_SKIP);
102 * These macros are intended to be used whenever you want allow a task that's
103 * sleeping in TASK_UNINTERRUPTIBLE or TASK_KILLABLE state to be frozen. Note
104 * that neither return any clear indication of whether a freeze event happened
105 * while in this function.
108 /* Like schedule(), but should not block the freezer. */
109 #define freezable_schedule() \
111 freezer_do_not_count(); \
116 /* Like schedule_timeout_killable(), but should not block the freezer. */
117 #define freezable_schedule_timeout_killable(timeout) \
120 freezer_do_not_count(); \
121 __retval = schedule_timeout_killable(timeout); \
127 * Freezer-friendly wrappers around wait_event_interruptible(),
128 * wait_event_killable() and wait_event_interruptible_timeout(), originally
129 * defined in <linux/wait.h>
132 #define wait_event_freezekillable(wq, condition) \
135 freezer_do_not_count(); \
136 __retval = wait_event_killable(wq, (condition)); \
141 #define wait_event_freezable(wq, condition) \
145 __retval = wait_event_interruptible(wq, \
146 (condition) || freezing(current)); \
147 if (__retval || (condition)) \
154 #define wait_event_freezable_timeout(wq, condition, timeout) \
156 long __retval = timeout; \
158 __retval = wait_event_interruptible_timeout(wq, \
159 (condition) || freezing(current), \
161 if (__retval <= 0 || (condition)) \
168 #else /* !CONFIG_FREEZER */
169 static inline bool frozen(struct task_struct *p) { return false; }
170 static inline bool freezing(struct task_struct *p) { return false; }
171 static inline void __thaw_task(struct task_struct *t) {}
173 static inline bool __refrigerator(bool check_kthr_stop) { return false; }
174 static inline int freeze_processes(void) { return -ENOSYS; }
175 static inline int freeze_kernel_threads(void) { return -ENOSYS; }
176 static inline void thaw_processes(void) {}
178 static inline bool try_to_freeze(void) { return false; }
180 static inline void freezer_do_not_count(void) {}
181 static inline void freezer_count(void) {}
182 static inline int freezer_should_skip(struct task_struct *p) { return 0; }
183 static inline void set_freezable(void) {}
185 #define freezable_schedule() schedule()
187 #define freezable_schedule_timeout_killable(timeout) \
188 schedule_timeout_killable(timeout)
190 #define wait_event_freezable(wq, condition) \
191 wait_event_interruptible(wq, condition)
193 #define wait_event_freezable_timeout(wq, condition, timeout) \
194 wait_event_interruptible_timeout(wq, condition, timeout)
196 #define wait_event_freezekillable(wq, condition) \
197 wait_event_killable(wq, condition)
199 #endif /* !CONFIG_FREEZER */
201 #endif /* FREEZER_H_INCLUDED */