1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Freezer declarations */
3
4 #ifndef FREEZER_H_INCLUDED
5 #define FREEZER_H_INCLUDED
6
7 #include <linux/debug_locks.h>
8 #include <linux/sched.h>
9 #include <linux/wait.h>
10 #include <linux/atomic.h>
11 #include <linux/jump_label.h>
12
13 #ifdef CONFIG_FREEZER
14 DECLARE_STATIC_KEY_FALSE(freezer_active);
15
16 extern bool pm_freezing; /* PM freezing in effect */
17 extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
18
19 /*
20 * Timeout for stopping processes
21 */
22 extern unsigned int freeze_timeout_msecs;
23
24 /*
25 * Check if a process has been frozen
26 */
27 extern bool frozen(struct task_struct *p);
28
29 extern bool freezing_slow_path(struct task_struct *p);
30
31 /*
32 * Check if there is a request to freeze a process
33 */
34 static inline bool freezing(struct task_struct *p)
35 {
36 if (static_branch_unlikely(&freezer_active))
37 return freezing_slow_path(p);
38
39 return false;
40 }
41
42 /* Takes and releases task alloc lock using task_lock() */
43 extern void __thaw_task(struct task_struct *t);
44
45 extern bool __refrigerator(bool check_kthr_stop);
46 extern int freeze_processes(void);
47 extern int freeze_kernel_threads(void);
48 extern void thaw_processes(void);
49 extern void thaw_kernel_threads(void);
50
51 static inline bool try_to_freeze(void)
52 {
53 might_sleep();
54 if (likely(!freezing(current)))
55 return false;
56 if (!(current->flags & PF_NOFREEZE))
57 debug_check_no_locks_held();
58 return __refrigerator(false);
59 }
60
61 extern bool freeze_task(struct task_struct *p);
62 extern bool set_freezable(void);
63
64 #ifdef CONFIG_CGROUP_FREEZER
65 extern bool cgroup_freezing(struct task_struct *task);
66 #else /* !CONFIG_CGROUP_FREEZER */
67 static inline bool cgroup_freezing(struct task_struct *task)
68 {
69 return false;
70 }
71 #endif /* !CONFIG_CGROUP_FREEZER */
72
73 #else /* !CONFIG_FREEZER */
74 static inline bool frozen(struct task_struct *p) { return false; }
75 static inline bool freezing(struct task_struct *p) { return false; }
76 static inline void __thaw_task(struct task_struct *t) {}
77
78 static inline bool __refrigerator(bool check_kthr_stop) { return false; }
79 static inline int freeze_processes(void) { return -ENOSYS; }
80 static inline int freeze_kernel_threads(void) { return -ENOSYS; }
81 static inline void thaw_processes(void) {}
82 static inline void thaw_kernel_threads(void) {}
83
84 static inline bool try_to_freeze(void) { return false; }
85
86 static inline void set_freezable(void) {}
87
88 #endif /* !CONFIG_FREEZER */
89
90 #endif /* FREEZER_H_INCLUDED */
91
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.