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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 | |
9 | #ifdef CONFIG_FREEZER |
10 | /* |
11 | * Check if a process has been frozen |
12 | */ |
13 | static inline int frozen(struct task_struct *p) |
14 | { |
15 | return p->flags & PF_FROZEN; |
16 | } |
17 | |
18 | /* |
19 | * Check if there is a request to freeze a process |
20 | */ |
21 | static inline int freezing(struct task_struct *p) |
22 | { |
23 | return test_tsk_thread_flag(p, TIF_FREEZE); |
24 | } |
25 | |
26 | /* |
27 | * Request that a process be frozen |
28 | */ |
29 | static inline void set_freeze_flag(struct task_struct *p) |
30 | { |
31 | set_tsk_thread_flag(p, TIF_FREEZE); |
32 | } |
33 | |
34 | /* |
35 | * Sometimes we may need to cancel the previous 'freeze' request |
36 | */ |
37 | static inline void clear_freeze_flag(struct task_struct *p) |
38 | { |
39 | clear_tsk_thread_flag(p, TIF_FREEZE); |
40 | } |
41 | |
42 | static inline bool should_send_signal(struct task_struct *p) |
43 | { |
44 | return !(p->flags & PF_FREEZER_NOSIG); |
45 | } |
46 | |
47 | /* Takes and releases task alloc lock using task_lock() */ |
48 | extern int thaw_process(struct task_struct *p); |
49 | |
50 | extern void refrigerator(void); |
51 | extern int freeze_processes(void); |
52 | extern void thaw_processes(void); |
53 | |
54 | static inline int try_to_freeze(void) |
55 | { |
56 | if (freezing(current)) { |
57 | refrigerator(); |
58 | return 1; |
59 | } else |
60 | return 0; |
61 | } |
62 | |
63 | extern bool freeze_task(struct task_struct *p, bool sig_only); |
64 | extern void cancel_freezing(struct task_struct *p); |
65 | |
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) |
70 | { |
71 | return 0; |
72 | } |
73 | #endif /* !CONFIG_CGROUP_FREEZER */ |
74 | |
75 | /* |
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 |
86 | * parent. |
87 | */ |
88 | |
89 | /* |
90 | * If the current task is a user space one, tell the freezer not to count it as |
91 | * freezable. |
92 | */ |
93 | static inline void freezer_do_not_count(void) |
94 | { |
95 | if (current->mm) |
96 | current->flags |= PF_FREEZER_SKIP; |
97 | } |
98 | |
99 | /* |
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. |
102 | */ |
103 | static inline void freezer_count(void) |
104 | { |
105 | if (current->mm) { |
106 | current->flags &= ~PF_FREEZER_SKIP; |
107 | try_to_freeze(); |
108 | } |
109 | } |
110 | |
111 | /* |
112 | * Check if the task should be counted as freezeable by the freezer |
113 | */ |
114 | static inline int freezer_should_skip(struct task_struct *p) |
115 | { |
116 | return !!(p->flags & PF_FREEZER_SKIP); |
117 | } |
118 | |
119 | /* |
120 | * Tell the freezer that the current task should be frozen by it |
121 | */ |
122 | static inline void set_freezable(void) |
123 | { |
124 | current->flags &= ~PF_NOFREEZE; |
125 | } |
126 | |
127 | /* |
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. |
130 | */ |
131 | static inline void set_freezable_with_signal(void) |
132 | { |
133 | current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG); |
134 | } |
135 | |
136 | /* |
137 | * Freezer-friendly wrappers around wait_event_interruptible() and |
138 | * wait_event_interruptible_timeout(), originally defined in <linux/wait.h> |
139 | */ |
140 | |
141 | #define wait_event_freezable(wq, condition) \ |
142 | ({ \ |
143 | int __retval; \ |
144 | do { \ |
145 | __retval = wait_event_interruptible(wq, \ |
146 | (condition) || freezing(current)); \ |
147 | if (__retval && !freezing(current)) \ |
148 | break; \ |
149 | else if (!(condition)) \ |
150 | __retval = -ERESTARTSYS; \ |
151 | } while (try_to_freeze()); \ |
152 | __retval; \ |
153 | }) |
154 | |
155 | |
156 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
157 | ({ \ |
158 | long __retval = timeout; \ |
159 | do { \ |
160 | __retval = wait_event_interruptible_timeout(wq, \ |
161 | (condition) || freezing(current), \ |
162 | __retval); \ |
163 | } while (try_to_freeze()); \ |
164 | __retval; \ |
165 | }) |
166 | #else /* !CONFIG_FREEZER */ |
167 | static inline int frozen(struct task_struct *p) { return 0; } |
168 | static inline int freezing(struct task_struct *p) { return 0; } |
169 | static inline void set_freeze_flag(struct task_struct *p) {} |
170 | static inline void clear_freeze_flag(struct task_struct *p) {} |
171 | static inline int thaw_process(struct task_struct *p) { return 1; } |
172 | |
173 | static inline void refrigerator(void) {} |
174 | static inline int freeze_processes(void) { BUG(); return 0; } |
175 | static inline void thaw_processes(void) {} |
176 | |
177 | static inline int try_to_freeze(void) { return 0; } |
178 | |
179 | static inline void freezer_do_not_count(void) {} |
180 | static inline void freezer_count(void) {} |
181 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } |
182 | static inline void set_freezable(void) {} |
183 | static inline void set_freezable_with_signal(void) {} |
184 | |
185 | #define wait_event_freezable(wq, condition) \ |
186 | wait_event_interruptible(wq, condition) |
187 | |
188 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
189 | wait_event_interruptible_timeout(wq, condition, timeout) |
190 | |
191 | #endif /* !CONFIG_FREEZER */ |
192 | |
193 | #endif /* FREEZER_H_INCLUDED */ |
194 |
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