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
14DECLARE_STATIC_KEY_FALSE(freezer_active);
15
16extern bool pm_freezing; /* PM freezing in effect */
17extern bool pm_nosig_freezing; /* PM nosig freezing in effect */
18
19/*
20 * Timeout for stopping processes
21 */
22extern unsigned int freeze_timeout_msecs;
23
24/*
25 * Check if a process has been frozen
26 */
27extern bool frozen(struct task_struct *p);
28
29extern bool freezing_slow_path(struct task_struct *p);
30
31/*
32 * Check if there is a request to freeze a process
33 */
34static 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() */
43extern void __thaw_task(struct task_struct *t);
44
45extern bool __refrigerator(bool check_kthr_stop);
46extern int freeze_processes(void);
47extern int freeze_kernel_threads(void);
48extern void thaw_processes(void);
49extern void thaw_kernel_threads(void);
50extern void thaw_process(struct task_struct *p);
51
52static inline bool try_to_freeze(void)
53{
54 might_sleep();
55 if (likely(!freezing(current)))
56 return false;
57 if (!(current->flags & PF_NOFREEZE))
58 debug_check_no_locks_held();
59 return __refrigerator(check_kthr_stop: false);
60}
61
62extern bool freeze_task(struct task_struct *p);
63extern bool set_freezable(void);
64
65#ifdef CONFIG_CGROUP_FREEZER
66extern bool cgroup_freezing(struct task_struct *task);
67#else /* !CONFIG_CGROUP_FREEZER */
68static inline bool cgroup_freezing(struct task_struct *task)
69{
70 return false;
71}
72#endif /* !CONFIG_CGROUP_FREEZER */
73
74#else /* !CONFIG_FREEZER */
75static inline bool frozen(struct task_struct *p) { return false; }
76static inline bool freezing(struct task_struct *p) { return false; }
77static inline void __thaw_task(struct task_struct *t) {}
78
79static inline bool __refrigerator(bool check_kthr_stop) { return false; }
80static inline int freeze_processes(void) { return -ENOSYS; }
81static inline int freeze_kernel_threads(void) { return -ENOSYS; }
82static inline void thaw_processes(void) {}
83static inline void thaw_kernel_threads(void) {}
84static inline void thaw_process(struct task_struct *p) {}
85
86static inline bool try_to_freeze(void) { return false; }
87
88static inline void set_freezable(void) {}
89
90#endif /* !CONFIG_FREEZER */
91
92#endif /* FREEZER_H_INCLUDED */
93