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> |
a3201227 | 8 | #include <linux/atomic.h> |
5c543eff | 9 | |
8174f150 | 10 | #ifdef CONFIG_FREEZER |
a3201227 TH |
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 | ||
957d1282 LF |
15 | /* |
16 | * Timeout for stopping processes | |
17 | */ | |
18 | extern unsigned int freeze_timeout_msecs; | |
19 | ||
7dfb7103 NC |
20 | /* |
21 | * Check if a process has been frozen | |
22 | */ | |
948246f7 | 23 | static inline bool frozen(struct task_struct *p) |
7dfb7103 NC |
24 | { |
25 | return p->flags & PF_FROZEN; | |
26 | } | |
27 | ||
a3201227 | 28 | extern bool freezing_slow_path(struct task_struct *p); |
7dfb7103 NC |
29 | |
30 | /* | |
a3201227 | 31 | * Check if there is a request to freeze a process |
7dfb7103 | 32 | */ |
a3201227 | 33 | static inline bool freezing(struct task_struct *p) |
7dfb7103 | 34 | { |
a3201227 TH |
35 | if (likely(!atomic_read(&system_freezing_cnt))) |
36 | return false; | |
37 | return freezing_slow_path(p); | |
7dfb7103 NC |
38 | } |
39 | ||
dc52ddc0 | 40 | /* Takes and releases task alloc lock using task_lock() */ |
a5be2d0d | 41 | extern void __thaw_task(struct task_struct *t); |
7dfb7103 | 42 | |
8a32c441 | 43 | extern bool __refrigerator(bool check_kthr_stop); |
7dfb7103 | 44 | extern int freeze_processes(void); |
2aede851 | 45 | extern int freeze_kernel_threads(void); |
a9b6f562 | 46 | extern void thaw_processes(void); |
181e9bde | 47 | extern void thaw_kernel_threads(void); |
7dfb7103 | 48 | |
a0acae0e | 49 | static inline bool try_to_freeze(void) |
7dfb7103 | 50 | { |
a0acae0e TH |
51 | might_sleep(); |
52 | if (likely(!freezing(current))) | |
53 | return false; | |
8a32c441 | 54 | return __refrigerator(false); |
7dfb7103 | 55 | } |
ff39593a | 56 | |
839e3407 | 57 | extern bool freeze_task(struct task_struct *p); |
34b087e4 | 58 | extern bool set_freezable(void); |
8174f150 | 59 | |
dc52ddc0 | 60 | #ifdef CONFIG_CGROUP_FREEZER |
22b4e111 | 61 | extern bool cgroup_freezing(struct task_struct *task); |
dc52ddc0 | 62 | #else /* !CONFIG_CGROUP_FREEZER */ |
22b4e111 | 63 | static inline bool cgroup_freezing(struct task_struct *task) |
5a7aadfe | 64 | { |
22b4e111 | 65 | return false; |
5a7aadfe | 66 | } |
dc52ddc0 MH |
67 | #endif /* !CONFIG_CGROUP_FREEZER */ |
68 | ||
ba96a0c8 RW |
69 | /* |
70 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
71 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
72 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
73 | * appropriately in case the child has exited before the freezing of tasks is | |
74 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
75 | * places, so we allow them to block freeze_processes() instead or to set | |
467de1fc SB |
76 | * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the |
77 | * parent won't really block freeze_processes(), since ____call_usermodehelper() | |
78 | * (the child) does a little before exec/exit and it can't be frozen before | |
79 | * waking up the parent. | |
ba96a0c8 RW |
80 | */ |
81 | ||
467de1fc | 82 | |
dd67d32d TH |
83 | /** |
84 | * freezer_do_not_count - tell freezer to ignore %current | |
85 | * | |
86 | * Tell freezers to ignore the current task when determining whether the | |
87 | * target frozen state is reached. IOW, the current task will be | |
88 | * considered frozen enough by freezers. | |
89 | * | |
90 | * The caller shouldn't do anything which isn't allowed for a frozen task | |
91 | * until freezer_cont() is called. Usually, freezer[_do_not]_count() pair | |
92 | * wrap a scheduling operation and nothing much else. | |
93 | */ | |
ba96a0c8 RW |
94 | static inline void freezer_do_not_count(void) |
95 | { | |
467de1fc | 96 | current->flags |= PF_FREEZER_SKIP; |
ba96a0c8 RW |
97 | } |
98 | ||
dd67d32d TH |
99 | /** |
100 | * freezer_count - tell freezer to stop ignoring %current | |
101 | * | |
102 | * Undo freezer_do_not_count(). It tells freezers that %current should be | |
103 | * considered again and tries to freeze if freezing condition is already in | |
104 | * effect. | |
ba96a0c8 RW |
105 | */ |
106 | static inline void freezer_count(void) | |
107 | { | |
467de1fc | 108 | current->flags &= ~PF_FREEZER_SKIP; |
dd67d32d TH |
109 | /* |
110 | * If freezing is in progress, the following paired with smp_mb() | |
111 | * in freezer_should_skip() ensures that either we see %true | |
112 | * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP. | |
113 | */ | |
114 | smp_mb(); | |
467de1fc | 115 | try_to_freeze(); |
ba96a0c8 RW |
116 | } |
117 | ||
dd67d32d TH |
118 | /** |
119 | * freezer_should_skip - whether to skip a task when determining frozen | |
120 | * state is reached | |
121 | * @p: task in quesion | |
122 | * | |
123 | * This function is used by freezers after establishing %true freezing() to | |
124 | * test whether a task should be skipped when determining the target frozen | |
125 | * state is reached. IOW, if this function returns %true, @p is considered | |
126 | * frozen enough. | |
ba96a0c8 | 127 | */ |
dd67d32d | 128 | static inline bool freezer_should_skip(struct task_struct *p) |
ba96a0c8 | 129 | { |
dd67d32d TH |
130 | /* |
131 | * The following smp_mb() paired with the one in freezer_count() | |
132 | * ensures that either freezer_count() sees %true freezing() or we | |
133 | * see cleared %PF_FREEZER_SKIP and return %false. This makes it | |
134 | * impossible for a task to slip frozen state testing after | |
135 | * clearing %PF_FREEZER_SKIP. | |
136 | */ | |
137 | smp_mb(); | |
138 | return p->flags & PF_FREEZER_SKIP; | |
ba96a0c8 | 139 | } |
ff39593a | 140 | |
d310310c | 141 | /* |
5d8f72b5 ON |
142 | * These macros are intended to be used whenever you want allow a sleeping |
143 | * task to be frozen. Note that neither return any clear indication of | |
144 | * whether a freeze event happened while in this function. | |
d310310c JL |
145 | */ |
146 | ||
147 | /* Like schedule(), but should not block the freezer. */ | |
148 | #define freezable_schedule() \ | |
149 | ({ \ | |
150 | freezer_do_not_count(); \ | |
151 | schedule(); \ | |
152 | freezer_count(); \ | |
153 | }) | |
154 | ||
155 | /* Like schedule_timeout_killable(), but should not block the freezer. */ | |
156 | #define freezable_schedule_timeout_killable(timeout) \ | |
157 | ({ \ | |
b3b73ec0 | 158 | long __retval; \ |
d310310c | 159 | freezer_do_not_count(); \ |
b3b73ec0 | 160 | __retval = schedule_timeout_killable(timeout); \ |
d310310c | 161 | freezer_count(); \ |
b3b73ec0 | 162 | __retval; \ |
d310310c JL |
163 | }) |
164 | ||
e42837bc | 165 | /* |
f06ac72e JL |
166 | * Freezer-friendly wrappers around wait_event_interruptible(), |
167 | * wait_event_killable() and wait_event_interruptible_timeout(), originally | |
168 | * defined in <linux/wait.h> | |
e42837bc RW |
169 | */ |
170 | ||
f06ac72e JL |
171 | #define wait_event_freezekillable(wq, condition) \ |
172 | ({ \ | |
173 | int __retval; \ | |
6f35c4ab ON |
174 | freezer_do_not_count(); \ |
175 | __retval = wait_event_killable(wq, (condition)); \ | |
176 | freezer_count(); \ | |
f06ac72e JL |
177 | __retval; \ |
178 | }) | |
179 | ||
e42837bc RW |
180 | #define wait_event_freezable(wq, condition) \ |
181 | ({ \ | |
182 | int __retval; \ | |
24b7ead3 | 183 | for (;;) { \ |
e42837bc RW |
184 | __retval = wait_event_interruptible(wq, \ |
185 | (condition) || freezing(current)); \ | |
24b7ead3 | 186 | if (__retval || (condition)) \ |
e42837bc | 187 | break; \ |
24b7ead3 ON |
188 | try_to_freeze(); \ |
189 | } \ | |
e42837bc RW |
190 | __retval; \ |
191 | }) | |
192 | ||
e42837bc RW |
193 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
194 | ({ \ | |
195 | long __retval = timeout; \ | |
24b7ead3 | 196 | for (;;) { \ |
e42837bc RW |
197 | __retval = wait_event_interruptible_timeout(wq, \ |
198 | (condition) || freezing(current), \ | |
199 | __retval); \ | |
24b7ead3 ON |
200 | if (__retval <= 0 || (condition)) \ |
201 | break; \ | |
202 | try_to_freeze(); \ | |
203 | } \ | |
e42837bc RW |
204 | __retval; \ |
205 | }) | |
24b7ead3 | 206 | |
8174f150 | 207 | #else /* !CONFIG_FREEZER */ |
948246f7 | 208 | static inline bool frozen(struct task_struct *p) { return false; } |
a3201227 | 209 | static inline bool freezing(struct task_struct *p) { return false; } |
62c9ea6b | 210 | static inline void __thaw_task(struct task_struct *t) {} |
7dfb7103 | 211 | |
8a32c441 | 212 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } |
2aede851 RW |
213 | static inline int freeze_processes(void) { return -ENOSYS; } |
214 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } | |
7dfb7103 | 215 | static inline void thaw_processes(void) {} |
181e9bde | 216 | static inline void thaw_kernel_threads(void) {} |
7dfb7103 | 217 | |
e5f57621 | 218 | static inline bool try_to_freeze_nowarn(void) { return false; } |
a0acae0e | 219 | static inline bool try_to_freeze(void) { return false; } |
7dfb7103 | 220 | |
ba96a0c8 RW |
221 | static inline void freezer_do_not_count(void) {} |
222 | static inline void freezer_count(void) {} | |
223 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 224 | static inline void set_freezable(void) {} |
e42837bc | 225 | |
d310310c JL |
226 | #define freezable_schedule() schedule() |
227 | ||
228 | #define freezable_schedule_timeout_killable(timeout) \ | |
229 | schedule_timeout_killable(timeout) | |
230 | ||
e42837bc RW |
231 | #define wait_event_freezable(wq, condition) \ |
232 | wait_event_interruptible(wq, condition) | |
233 | ||
234 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
235 | wait_event_interruptible_timeout(wq, condition, timeout) | |
236 | ||
e0c8ea1a SF |
237 | #define wait_event_freezekillable(wq, condition) \ |
238 | wait_event_killable(wq, condition) | |
239 | ||
8174f150 | 240 | #endif /* !CONFIG_FREEZER */ |
83144186 RW |
241 | |
242 | #endif /* FREEZER_H_INCLUDED */ |