Commit | Line | Data |
---|---|---|
7dfb7103 NC |
1 | /* Freezer declarations */ |
2 | ||
83144186 RW |
3 | #ifndef FREEZER_H_INCLUDED |
4 | #define FREEZER_H_INCLUDED | |
5 | ||
5c543eff | 6 | #include <linux/sched.h> |
e42837bc | 7 | #include <linux/wait.h> |
5c543eff | 8 | |
296699de | 9 | #ifdef CONFIG_PM_SLEEP |
7dfb7103 NC |
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 | { | |
8a102eed | 23 | return test_tsk_thread_flag(p, TIF_FREEZE); |
7dfb7103 NC |
24 | } |
25 | ||
26 | /* | |
27 | * Request that a process be frozen | |
7dfb7103 | 28 | */ |
0c1eecfb | 29 | static inline void set_freeze_flag(struct task_struct *p) |
7dfb7103 | 30 | { |
8a102eed | 31 | set_tsk_thread_flag(p, TIF_FREEZE); |
7dfb7103 NC |
32 | } |
33 | ||
34 | /* | |
35 | * Sometimes we may need to cancel the previous 'freeze' request | |
36 | */ | |
0c1eecfb | 37 | static inline void clear_freeze_flag(struct task_struct *p) |
7dfb7103 | 38 | { |
8a102eed | 39 | clear_tsk_thread_flag(p, TIF_FREEZE); |
7dfb7103 NC |
40 | } |
41 | ||
42 | /* | |
43 | * Wake up a frozen process | |
33e1c288 RW |
44 | * |
45 | * task_lock() is taken to prevent the race with refrigerator() which may | |
46 | * occur if the freezing of tasks fails. Namely, without the lock, if the | |
47 | * freezing of tasks failed, thaw_tasks() might have run before a task in | |
48 | * refrigerator() could call frozen_process(), in which case the task would be | |
49 | * frozen and no one would thaw it. | |
7dfb7103 NC |
50 | */ |
51 | static inline int thaw_process(struct task_struct *p) | |
52 | { | |
33e1c288 | 53 | task_lock(p); |
7dfb7103 NC |
54 | if (frozen(p)) { |
55 | p->flags &= ~PF_FROZEN; | |
33e1c288 | 56 | task_unlock(p); |
7dfb7103 NC |
57 | wake_up_process(p); |
58 | return 1; | |
59 | } | |
0c1eecfb | 60 | clear_freeze_flag(p); |
33e1c288 | 61 | task_unlock(p); |
7dfb7103 NC |
62 | return 0; |
63 | } | |
64 | ||
7dfb7103 NC |
65 | extern void refrigerator(void); |
66 | extern int freeze_processes(void); | |
a9b6f562 | 67 | extern void thaw_processes(void); |
7dfb7103 NC |
68 | |
69 | static inline int try_to_freeze(void) | |
70 | { | |
71 | if (freezing(current)) { | |
72 | refrigerator(); | |
73 | return 1; | |
74 | } else | |
75 | return 0; | |
76 | } | |
ff39593a | 77 | |
ba96a0c8 RW |
78 | /* |
79 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
80 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
81 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
82 | * appropriately in case the child has exited before the freezing of tasks is | |
83 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
84 | * places, so we allow them to block freeze_processes() instead or to set | |
85 | * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork | |
86 | * parents. Fortunately, in the ____call_usermodehelper() case the parent won't | |
87 | * really block freeze_processes(), since ____call_usermodehelper() (the child) | |
88 | * does a little before exec/exit and it can't be frozen before waking up the | |
89 | * parent. | |
90 | */ | |
91 | ||
92 | /* | |
93 | * If the current task is a user space one, tell the freezer not to count it as | |
94 | * freezable. | |
95 | */ | |
96 | static inline void freezer_do_not_count(void) | |
97 | { | |
98 | if (current->mm) | |
99 | current->flags |= PF_FREEZER_SKIP; | |
100 | } | |
101 | ||
102 | /* | |
103 | * If the current task is a user space one, tell the freezer to count it as | |
104 | * freezable again and try to freeze it. | |
105 | */ | |
106 | static inline void freezer_count(void) | |
107 | { | |
108 | if (current->mm) { | |
109 | current->flags &= ~PF_FREEZER_SKIP; | |
110 | try_to_freeze(); | |
111 | } | |
112 | } | |
113 | ||
114 | /* | |
115 | * Check if the task should be counted as freezeable by the freezer | |
116 | */ | |
117 | static inline int freezer_should_skip(struct task_struct *p) | |
118 | { | |
119 | return !!(p->flags & PF_FREEZER_SKIP); | |
120 | } | |
ff39593a | 121 | |
83144186 RW |
122 | /* |
123 | * Tell the freezer that the current task should be frozen by it | |
124 | */ | |
125 | static inline void set_freezable(void) | |
126 | { | |
127 | current->flags &= ~PF_NOFREEZE; | |
128 | } | |
129 | ||
e42837bc RW |
130 | /* |
131 | * Freezer-friendly wrappers around wait_event_interruptible() and | |
132 | * wait_event_interruptible_timeout(), originally defined in <linux/wait.h> | |
133 | */ | |
134 | ||
135 | #define wait_event_freezable(wq, condition) \ | |
136 | ({ \ | |
137 | int __retval; \ | |
138 | do { \ | |
139 | __retval = wait_event_interruptible(wq, \ | |
140 | (condition) || freezing(current)); \ | |
141 | if (__retval && !freezing(current)) \ | |
142 | break; \ | |
143 | else if (!(condition)) \ | |
144 | __retval = -ERESTARTSYS; \ | |
145 | } while (try_to_freeze()); \ | |
146 | __retval; \ | |
147 | }) | |
148 | ||
149 | ||
150 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
151 | ({ \ | |
152 | long __retval = timeout; \ | |
153 | do { \ | |
154 | __retval = wait_event_interruptible_timeout(wq, \ | |
155 | (condition) || freezing(current), \ | |
156 | __retval); \ | |
157 | } while (try_to_freeze()); \ | |
158 | __retval; \ | |
159 | }) | |
296699de | 160 | #else /* !CONFIG_PM_SLEEP */ |
7dfb7103 NC |
161 | static inline int frozen(struct task_struct *p) { return 0; } |
162 | static inline int freezing(struct task_struct *p) { return 0; } | |
0c1eecfb RW |
163 | static inline void set_freeze_flag(struct task_struct *p) {} |
164 | static inline void clear_freeze_flag(struct task_struct *p) {} | |
7dfb7103 | 165 | static inline int thaw_process(struct task_struct *p) { return 1; } |
7dfb7103 NC |
166 | |
167 | static inline void refrigerator(void) {} | |
168 | static inline int freeze_processes(void) { BUG(); return 0; } | |
169 | static inline void thaw_processes(void) {} | |
170 | ||
171 | static inline int try_to_freeze(void) { return 0; } | |
172 | ||
ba96a0c8 RW |
173 | static inline void freezer_do_not_count(void) {} |
174 | static inline void freezer_count(void) {} | |
175 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 176 | static inline void set_freezable(void) {} |
e42837bc RW |
177 | |
178 | #define wait_event_freezable(wq, condition) \ | |
179 | wait_event_interruptible(wq, condition) | |
180 | ||
181 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
182 | wait_event_interruptible_timeout(wq, condition, timeout) | |
183 | ||
296699de | 184 | #endif /* !CONFIG_PM_SLEEP */ |
83144186 RW |
185 | |
186 | #endif /* FREEZER_H_INCLUDED */ |