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  */
freezing(struct task_struct * p)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 
try_to_freeze(void)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 */
cgroup_freezing(struct task_struct * task)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 */
frozen(struct task_struct * p)74 static inline bool frozen(struct task_struct *p) { return false; }
freezing(struct task_struct * p)75 static inline bool freezing(struct task_struct *p) { return false; }
__thaw_task(struct task_struct * t)76 static inline void __thaw_task(struct task_struct *t) {}
77 
__refrigerator(bool check_kthr_stop)78 static inline bool __refrigerator(bool check_kthr_stop) { return false; }
freeze_processes(void)79 static inline int freeze_processes(void) { return -ENOSYS; }
freeze_kernel_threads(void)80 static inline int freeze_kernel_threads(void) { return -ENOSYS; }
thaw_processes(void)81 static inline void thaw_processes(void) {}
thaw_kernel_threads(void)82 static inline void thaw_kernel_threads(void) {}
83 
try_to_freeze(void)84 static inline bool try_to_freeze(void) { return false; }
85 
set_freezable(void)86 static inline void set_freezable(void) {}
87 
88 #endif /* !CONFIG_FREEZER */
89 
90 #endif	/* FREEZER_H_INCLUDED */
91