1 /* Freezer declarations */
3 #ifndef FREEZER_H_INCLUDED
4 #define FREEZER_H_INCLUDED
6 #include <linux/sched.h>
7 #include <linux/wait.h>
11 * Check if a process has been frozen
13 static inline int frozen(struct task_struct *p)
15 return p->flags & PF_FROZEN;
19 * Check if there is a request to freeze a process
21 static inline int freezing(struct task_struct *p)
23 return test_tsk_thread_flag(p, TIF_FREEZE);
27 * Request that a process be frozen
29 static inline void set_freeze_flag(struct task_struct *p)
31 set_tsk_thread_flag(p, TIF_FREEZE);
35 * Sometimes we may need to cancel the previous 'freeze' request
37 static inline void clear_freeze_flag(struct task_struct *p)
39 clear_tsk_thread_flag(p, TIF_FREEZE);
42 static inline bool should_send_signal(struct task_struct *p)
44 return !(p->flags & PF_FREEZER_NOSIG);
47 /* Takes and releases task alloc lock using task_lock() */
48 extern int thaw_process(struct task_struct *p);
50 extern bool __refrigerator(void);
51 extern int freeze_processes(void);
52 extern int freeze_kernel_threads(void);
53 extern void thaw_processes(void);
55 static inline bool try_to_freeze(void)
58 if (likely(!freezing(current)))
60 return __refrigerator();
63 extern bool freeze_task(struct task_struct *p, bool sig_only);
64 extern void cancel_freezing(struct task_struct *p);
66 #ifdef CONFIG_CGROUP_FREEZER
67 extern int cgroup_freezing_or_frozen(struct task_struct *task);
68 #else /* !CONFIG_CGROUP_FREEZER */
69 static inline int cgroup_freezing_or_frozen(struct task_struct *task)
73 #endif /* !CONFIG_CGROUP_FREEZER */
76 * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
77 * calls wait_for_completion(&vfork) and reset right after it returns from this
78 * function. Next, the parent should call try_to_freeze() to freeze itself
79 * appropriately in case the child has exited before the freezing of tasks is
80 * complete. However, we don't want kernel threads to be frozen in unexpected
81 * places, so we allow them to block freeze_processes() instead or to set
82 * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork
83 * parents. Fortunately, in the ____call_usermodehelper() case the parent won't
84 * really block freeze_processes(), since ____call_usermodehelper() (the child)
85 * does a little before exec/exit and it can't be frozen before waking up the
90 * If the current task is a user space one, tell the freezer not to count it as
93 static inline void freezer_do_not_count(void)
96 current->flags |= PF_FREEZER_SKIP;
100 * If the current task is a user space one, tell the freezer to count it as
101 * freezable again and try to freeze it.
103 static inline void freezer_count(void)
106 current->flags &= ~PF_FREEZER_SKIP;
112 * Check if the task should be counted as freezable by the freezer
114 static inline int freezer_should_skip(struct task_struct *p)
116 return !!(p->flags & PF_FREEZER_SKIP);
120 * Tell the freezer that the current task should be frozen by it
122 static inline void set_freezable(void)
124 current->flags &= ~PF_NOFREEZE;
128 * Tell the freezer that the current task should be frozen by it and that it
129 * should send a fake signal to the task to freeze it.
131 static inline void set_freezable_with_signal(void)
133 current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG);
137 * Freezer-friendly wrappers around wait_event_interruptible(),
138 * wait_event_killable() and wait_event_interruptible_timeout(), originally
139 * defined in <linux/wait.h>
142 #define wait_event_freezekillable(wq, condition) \
145 freezer_do_not_count(); \
146 __retval = wait_event_killable(wq, (condition)); \
151 #define wait_event_freezable(wq, condition) \
155 __retval = wait_event_interruptible(wq, \
156 (condition) || freezing(current)); \
157 if (__retval && !freezing(current)) \
159 else if (!(condition)) \
160 __retval = -ERESTARTSYS; \
161 } while (try_to_freeze()); \
166 #define wait_event_freezable_timeout(wq, condition, timeout) \
168 long __retval = timeout; \
170 __retval = wait_event_interruptible_timeout(wq, \
171 (condition) || freezing(current), \
173 } while (try_to_freeze()); \
176 #else /* !CONFIG_FREEZER */
177 static inline int frozen(struct task_struct *p) { return 0; }
178 static inline int freezing(struct task_struct *p) { return 0; }
179 static inline void set_freeze_flag(struct task_struct *p) {}
180 static inline void clear_freeze_flag(struct task_struct *p) {}
181 static inline int thaw_process(struct task_struct *p) { return 1; }
183 static inline bool __refrigerator(void) { return false; }
184 static inline int freeze_processes(void) { return -ENOSYS; }
185 static inline int freeze_kernel_threads(void) { return -ENOSYS; }
186 static inline void thaw_processes(void) {}
188 static inline bool try_to_freeze(void) { return false; }
190 static inline void freezer_do_not_count(void) {}
191 static inline void freezer_count(void) {}
192 static inline int freezer_should_skip(struct task_struct *p) { return 0; }
193 static inline void set_freezable(void) {}
194 static inline void set_freezable_with_signal(void) {}
196 #define wait_event_freezable(wq, condition) \
197 wait_event_interruptible(wq, condition)
199 #define wait_event_freezable_timeout(wq, condition, timeout) \
200 wait_event_interruptible_timeout(wq, condition, timeout)
202 #define wait_event_freezekillable(wq, condition) \
203 wait_event_killable(wq, condition)
205 #endif /* !CONFIG_FREEZER */
207 #endif /* FREEZER_H_INCLUDED */