Commit | Line | Data |
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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 | |
8174f150 | 9 | #ifdef CONFIG_FREEZER |
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 | ||
8174f150 MH |
42 | static inline bool should_send_signal(struct task_struct *p) |
43 | { | |
44 | return !(p->flags & PF_FREEZER_NOSIG); | |
45 | } | |
46 | ||
7dfb7103 NC |
47 | /* |
48 | * Wake up a frozen process | |
33e1c288 RW |
49 | * |
50 | * task_lock() is taken to prevent the race with refrigerator() which may | |
51 | * occur if the freezing of tasks fails. Namely, without the lock, if the | |
52 | * freezing of tasks failed, thaw_tasks() might have run before a task in | |
53 | * refrigerator() could call frozen_process(), in which case the task would be | |
54 | * frozen and no one would thaw it. | |
7dfb7103 NC |
55 | */ |
56 | static inline int thaw_process(struct task_struct *p) | |
57 | { | |
33e1c288 | 58 | task_lock(p); |
7dfb7103 NC |
59 | if (frozen(p)) { |
60 | p->flags &= ~PF_FROZEN; | |
33e1c288 | 61 | task_unlock(p); |
7dfb7103 NC |
62 | wake_up_process(p); |
63 | return 1; | |
64 | } | |
0c1eecfb | 65 | clear_freeze_flag(p); |
33e1c288 | 66 | task_unlock(p); |
7dfb7103 NC |
67 | return 0; |
68 | } | |
69 | ||
7dfb7103 NC |
70 | extern void refrigerator(void); |
71 | extern int freeze_processes(void); | |
a9b6f562 | 72 | extern void thaw_processes(void); |
7dfb7103 NC |
73 | |
74 | static inline int try_to_freeze(void) | |
75 | { | |
76 | if (freezing(current)) { | |
77 | refrigerator(); | |
78 | return 1; | |
79 | } else | |
80 | return 0; | |
81 | } | |
ff39593a | 82 | |
8174f150 MH |
83 | extern bool freeze_task(struct task_struct *p, bool sig_only); |
84 | extern void cancel_freezing(struct task_struct *p); | |
85 | ||
ba96a0c8 RW |
86 | /* |
87 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
88 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
89 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
90 | * appropriately in case the child has exited before the freezing of tasks is | |
91 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
92 | * places, so we allow them to block freeze_processes() instead or to set | |
93 | * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork | |
94 | * parents. Fortunately, in the ____call_usermodehelper() case the parent won't | |
95 | * really block freeze_processes(), since ____call_usermodehelper() (the child) | |
96 | * does a little before exec/exit and it can't be frozen before waking up the | |
97 | * parent. | |
98 | */ | |
99 | ||
100 | /* | |
101 | * If the current task is a user space one, tell the freezer not to count it as | |
102 | * freezable. | |
103 | */ | |
104 | static inline void freezer_do_not_count(void) | |
105 | { | |
106 | if (current->mm) | |
107 | current->flags |= PF_FREEZER_SKIP; | |
108 | } | |
109 | ||
110 | /* | |
111 | * If the current task is a user space one, tell the freezer to count it as | |
112 | * freezable again and try to freeze it. | |
113 | */ | |
114 | static inline void freezer_count(void) | |
115 | { | |
116 | if (current->mm) { | |
117 | current->flags &= ~PF_FREEZER_SKIP; | |
118 | try_to_freeze(); | |
119 | } | |
120 | } | |
121 | ||
122 | /* | |
123 | * Check if the task should be counted as freezeable by the freezer | |
124 | */ | |
125 | static inline int freezer_should_skip(struct task_struct *p) | |
126 | { | |
127 | return !!(p->flags & PF_FREEZER_SKIP); | |
128 | } | |
ff39593a | 129 | |
83144186 RW |
130 | /* |
131 | * Tell the freezer that the current task should be frozen by it | |
132 | */ | |
133 | static inline void set_freezable(void) | |
134 | { | |
135 | current->flags &= ~PF_NOFREEZE; | |
136 | } | |
137 | ||
ebb12db5 RW |
138 | /* |
139 | * Tell the freezer that the current task should be frozen by it and that it | |
140 | * should send a fake signal to the task to freeze it. | |
141 | */ | |
142 | static inline void set_freezable_with_signal(void) | |
143 | { | |
144 | current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG); | |
145 | } | |
146 | ||
e42837bc RW |
147 | /* |
148 | * Freezer-friendly wrappers around wait_event_interruptible() and | |
149 | * wait_event_interruptible_timeout(), originally defined in <linux/wait.h> | |
150 | */ | |
151 | ||
152 | #define wait_event_freezable(wq, condition) \ | |
153 | ({ \ | |
154 | int __retval; \ | |
155 | do { \ | |
156 | __retval = wait_event_interruptible(wq, \ | |
157 | (condition) || freezing(current)); \ | |
158 | if (__retval && !freezing(current)) \ | |
159 | break; \ | |
160 | else if (!(condition)) \ | |
161 | __retval = -ERESTARTSYS; \ | |
162 | } while (try_to_freeze()); \ | |
163 | __retval; \ | |
164 | }) | |
165 | ||
166 | ||
167 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
168 | ({ \ | |
169 | long __retval = timeout; \ | |
170 | do { \ | |
171 | __retval = wait_event_interruptible_timeout(wq, \ | |
172 | (condition) || freezing(current), \ | |
173 | __retval); \ | |
174 | } while (try_to_freeze()); \ | |
175 | __retval; \ | |
176 | }) | |
8174f150 | 177 | #else /* !CONFIG_FREEZER */ |
7dfb7103 NC |
178 | static inline int frozen(struct task_struct *p) { return 0; } |
179 | static inline int freezing(struct task_struct *p) { return 0; } | |
0c1eecfb RW |
180 | static inline void set_freeze_flag(struct task_struct *p) {} |
181 | static inline void clear_freeze_flag(struct task_struct *p) {} | |
7dfb7103 | 182 | static inline int thaw_process(struct task_struct *p) { return 1; } |
7dfb7103 NC |
183 | |
184 | static inline void refrigerator(void) {} | |
185 | static inline int freeze_processes(void) { BUG(); return 0; } | |
186 | static inline void thaw_processes(void) {} | |
187 | ||
188 | static inline int try_to_freeze(void) { return 0; } | |
189 | ||
ba96a0c8 RW |
190 | static inline void freezer_do_not_count(void) {} |
191 | static inline void freezer_count(void) {} | |
192 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 193 | static inline void set_freezable(void) {} |
ebb12db5 | 194 | static inline void set_freezable_with_signal(void) {} |
e42837bc RW |
195 | |
196 | #define wait_event_freezable(wq, condition) \ | |
197 | wait_event_interruptible(wq, condition) | |
198 | ||
199 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
200 | wait_event_interruptible_timeout(wq, condition, timeout) | |
201 | ||
8174f150 | 202 | #endif /* !CONFIG_FREEZER */ |
83144186 RW |
203 | |
204 | #endif /* FREEZER_H_INCLUDED */ |