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1 | /* Freezer declarations */ | |
2 | ||
3 | #ifndef FREEZER_H_INCLUDED | |
4 | #define FREEZER_H_INCLUDED | |
5 | ||
6 | #include <linux/sched.h> | |
7 | #include <linux/wait.h> | |
8 | #include <linux/atomic.h> | |
9 | ||
10 | #ifdef CONFIG_FREEZER | |
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 */ | |
14 | ||
15 | /* | |
16 | * Check if a process has been frozen | |
17 | */ | |
18 | static inline bool frozen(struct task_struct *p) | |
19 | { | |
20 | return p->flags & PF_FROZEN; | |
21 | } | |
22 | ||
23 | extern bool freezing_slow_path(struct task_struct *p); | |
24 | ||
25 | /* | |
26 | * Check if there is a request to freeze a process | |
27 | */ | |
28 | static inline bool freezing(struct task_struct *p) | |
29 | { | |
30 | if (likely(!atomic_read(&system_freezing_cnt))) | |
31 | return false; | |
32 | return freezing_slow_path(p); | |
33 | } | |
34 | ||
35 | /* Takes and releases task alloc lock using task_lock() */ | |
36 | extern void __thaw_task(struct task_struct *t); | |
37 | ||
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); | |
42 | ||
43 | static inline bool try_to_freeze(void) | |
44 | { | |
45 | might_sleep(); | |
46 | if (likely(!freezing(current))) | |
47 | return false; | |
48 | return __refrigerator(false); | |
49 | } | |
50 | ||
51 | extern bool freeze_task(struct task_struct *p); | |
52 | extern bool set_freezable(void); | |
53 | ||
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) | |
58 | { | |
59 | return false; | |
60 | } | |
61 | #endif /* !CONFIG_CGROUP_FREEZER */ | |
62 | ||
63 | /* | |
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 and PF_FREEZER_SKIP is only set for userland vfork | |
71 | * parents. Fortunately, in the ____call_usermodehelper() case the parent won't | |
72 | * really block freeze_processes(), since ____call_usermodehelper() (the child) | |
73 | * does a little before exec/exit and it can't be frozen before waking up the | |
74 | * parent. | |
75 | */ | |
76 | ||
77 | /* | |
78 | * If the current task is a user space one, tell the freezer not to count it as | |
79 | * freezable. | |
80 | */ | |
81 | static inline void freezer_do_not_count(void) | |
82 | { | |
83 | if (current->mm) | |
84 | current->flags |= PF_FREEZER_SKIP; | |
85 | } | |
86 | ||
87 | /* | |
88 | * If the current task is a user space one, tell the freezer to count it as | |
89 | * freezable again and try to freeze it. | |
90 | */ | |
91 | static inline void freezer_count(void) | |
92 | { | |
93 | if (current->mm) { | |
94 | current->flags &= ~PF_FREEZER_SKIP; | |
95 | try_to_freeze(); | |
96 | } | |
97 | } | |
98 | ||
99 | /* | |
100 | * Check if the task should be counted as freezable by the freezer | |
101 | */ | |
102 | static inline int freezer_should_skip(struct task_struct *p) | |
103 | { | |
104 | return !!(p->flags & PF_FREEZER_SKIP); | |
105 | } | |
106 | ||
107 | /* | |
108 | * Freezer-friendly wrappers around wait_event_interruptible(), | |
109 | * wait_event_killable() and wait_event_interruptible_timeout(), originally | |
110 | * defined in <linux/wait.h> | |
111 | */ | |
112 | ||
113 | #define wait_event_freezekillable(wq, condition) \ | |
114 | ({ \ | |
115 | int __retval; \ | |
116 | freezer_do_not_count(); \ | |
117 | __retval = wait_event_killable(wq, (condition)); \ | |
118 | freezer_count(); \ | |
119 | __retval; \ | |
120 | }) | |
121 | ||
122 | #define wait_event_freezable(wq, condition) \ | |
123 | ({ \ | |
124 | int __retval; \ | |
125 | for (;;) { \ | |
126 | __retval = wait_event_interruptible(wq, \ | |
127 | (condition) || freezing(current)); \ | |
128 | if (__retval || (condition)) \ | |
129 | break; \ | |
130 | try_to_freeze(); \ | |
131 | } \ | |
132 | __retval; \ | |
133 | }) | |
134 | ||
135 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
136 | ({ \ | |
137 | long __retval = timeout; \ | |
138 | for (;;) { \ | |
139 | __retval = wait_event_interruptible_timeout(wq, \ | |
140 | (condition) || freezing(current), \ | |
141 | __retval); \ | |
142 | if (__retval <= 0 || (condition)) \ | |
143 | break; \ | |
144 | try_to_freeze(); \ | |
145 | } \ | |
146 | __retval; \ | |
147 | }) | |
148 | ||
149 | #else /* !CONFIG_FREEZER */ | |
150 | static inline bool frozen(struct task_struct *p) { return false; } | |
151 | static inline bool freezing(struct task_struct *p) { return false; } | |
152 | static inline void __thaw_task(struct task_struct *t) {} | |
153 | ||
154 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } | |
155 | static inline int freeze_processes(void) { return -ENOSYS; } | |
156 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } | |
157 | static inline void thaw_processes(void) {} | |
158 | ||
159 | static inline bool try_to_freeze(void) { return false; } | |
160 | ||
161 | static inline void freezer_do_not_count(void) {} | |
162 | static inline void freezer_count(void) {} | |
163 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
164 | static inline void set_freezable(void) {} | |
165 | ||
166 | #define wait_event_freezable(wq, condition) \ | |
167 | wait_event_interruptible(wq, condition) | |
168 | ||
169 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
170 | wait_event_interruptible_timeout(wq, condition, timeout) | |
171 | ||
172 | #define wait_event_freezekillable(wq, condition) \ | |
173 | wait_event_killable(wq, condition) | |
174 | ||
175 | #endif /* !CONFIG_FREEZER */ | |
176 | ||
177 | #endif /* FREEZER_H_INCLUDED */ |