Commit | Line | Data |
---|---|---|
7dfb7103 NC |
1 | /* Freezer declarations */ |
2 | ||
83144186 RW |
3 | #ifndef FREEZER_H_INCLUDED |
4 | #define FREEZER_H_INCLUDED | |
5 | ||
0f9548ca | 6 | #include <linux/debug_locks.h> |
5c543eff | 7 | #include <linux/sched.h> |
e42837bc | 8 | #include <linux/wait.h> |
a3201227 | 9 | #include <linux/atomic.h> |
5c543eff | 10 | |
8174f150 | 11 | #ifdef CONFIG_FREEZER |
a3201227 TH |
12 | extern atomic_t system_freezing_cnt; /* nr of freezing conds in effect */ |
13 | extern bool pm_freezing; /* PM freezing in effect */ | |
14 | extern bool pm_nosig_freezing; /* PM nosig freezing in effect */ | |
15 | ||
957d1282 LF |
16 | /* |
17 | * Timeout for stopping processes | |
18 | */ | |
19 | extern unsigned int freeze_timeout_msecs; | |
20 | ||
7dfb7103 NC |
21 | /* |
22 | * Check if a process has been frozen | |
23 | */ | |
948246f7 | 24 | static inline bool frozen(struct task_struct *p) |
7dfb7103 NC |
25 | { |
26 | return p->flags & PF_FROZEN; | |
27 | } | |
28 | ||
a3201227 | 29 | extern bool freezing_slow_path(struct task_struct *p); |
7dfb7103 NC |
30 | |
31 | /* | |
a3201227 | 32 | * Check if there is a request to freeze a process |
7dfb7103 | 33 | */ |
a3201227 | 34 | static inline bool freezing(struct task_struct *p) |
7dfb7103 | 35 | { |
a3201227 TH |
36 | if (likely(!atomic_read(&system_freezing_cnt))) |
37 | return false; | |
38 | return freezing_slow_path(p); | |
7dfb7103 NC |
39 | } |
40 | ||
dc52ddc0 | 41 | /* Takes and releases task alloc lock using task_lock() */ |
a5be2d0d | 42 | extern void __thaw_task(struct task_struct *t); |
7dfb7103 | 43 | |
8a32c441 | 44 | extern bool __refrigerator(bool check_kthr_stop); |
7dfb7103 | 45 | extern int freeze_processes(void); |
2aede851 | 46 | extern int freeze_kernel_threads(void); |
a9b6f562 | 47 | extern void thaw_processes(void); |
181e9bde | 48 | extern void thaw_kernel_threads(void); |
7dfb7103 | 49 | |
416ad3c9 CC |
50 | /* |
51 | * DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION | |
52 | * If try_to_freeze causes a lockdep warning it means the caller may deadlock | |
53 | */ | |
54 | static inline bool try_to_freeze_unsafe(void) | |
7dfb7103 | 55 | { |
a0acae0e TH |
56 | might_sleep(); |
57 | if (likely(!freezing(current))) | |
58 | return false; | |
8a32c441 | 59 | return __refrigerator(false); |
7dfb7103 | 60 | } |
ff39593a | 61 | |
416ad3c9 CC |
62 | static inline bool try_to_freeze(void) |
63 | { | |
0f9548ca MSB |
64 | if (!(current->flags & PF_NOFREEZE)) |
65 | debug_check_no_locks_held(); | |
416ad3c9 CC |
66 | return try_to_freeze_unsafe(); |
67 | } | |
68 | ||
839e3407 | 69 | extern bool freeze_task(struct task_struct *p); |
34b087e4 | 70 | extern bool set_freezable(void); |
8174f150 | 71 | |
dc52ddc0 | 72 | #ifdef CONFIG_CGROUP_FREEZER |
22b4e111 | 73 | extern bool cgroup_freezing(struct task_struct *task); |
dc52ddc0 | 74 | #else /* !CONFIG_CGROUP_FREEZER */ |
22b4e111 | 75 | static inline bool cgroup_freezing(struct task_struct *task) |
5a7aadfe | 76 | { |
22b4e111 | 77 | return false; |
5a7aadfe | 78 | } |
dc52ddc0 MH |
79 | #endif /* !CONFIG_CGROUP_FREEZER */ |
80 | ||
ba96a0c8 RW |
81 | /* |
82 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
83 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
84 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
85 | * appropriately in case the child has exited before the freezing of tasks is | |
86 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
87 | * places, so we allow them to block freeze_processes() instead or to set | |
467de1fc SB |
88 | * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the |
89 | * parent won't really block freeze_processes(), since ____call_usermodehelper() | |
90 | * (the child) does a little before exec/exit and it can't be frozen before | |
91 | * waking up the parent. | |
ba96a0c8 RW |
92 | */ |
93 | ||
467de1fc | 94 | |
dd67d32d TH |
95 | /** |
96 | * freezer_do_not_count - tell freezer to ignore %current | |
97 | * | |
98 | * Tell freezers to ignore the current task when determining whether the | |
99 | * target frozen state is reached. IOW, the current task will be | |
100 | * considered frozen enough by freezers. | |
101 | * | |
102 | * The caller shouldn't do anything which isn't allowed for a frozen task | |
103 | * until freezer_cont() is called. Usually, freezer[_do_not]_count() pair | |
104 | * wrap a scheduling operation and nothing much else. | |
105 | */ | |
ba96a0c8 RW |
106 | static inline void freezer_do_not_count(void) |
107 | { | |
467de1fc | 108 | current->flags |= PF_FREEZER_SKIP; |
ba96a0c8 RW |
109 | } |
110 | ||
dd67d32d TH |
111 | /** |
112 | * freezer_count - tell freezer to stop ignoring %current | |
113 | * | |
114 | * Undo freezer_do_not_count(). It tells freezers that %current should be | |
115 | * considered again and tries to freeze if freezing condition is already in | |
116 | * effect. | |
ba96a0c8 RW |
117 | */ |
118 | static inline void freezer_count(void) | |
119 | { | |
467de1fc | 120 | current->flags &= ~PF_FREEZER_SKIP; |
dd67d32d TH |
121 | /* |
122 | * If freezing is in progress, the following paired with smp_mb() | |
123 | * in freezer_should_skip() ensures that either we see %true | |
124 | * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP. | |
125 | */ | |
126 | smp_mb(); | |
467de1fc | 127 | try_to_freeze(); |
ba96a0c8 RW |
128 | } |
129 | ||
416ad3c9 CC |
130 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
131 | static inline void freezer_count_unsafe(void) | |
132 | { | |
133 | current->flags &= ~PF_FREEZER_SKIP; | |
134 | smp_mb(); | |
135 | try_to_freeze_unsafe(); | |
136 | } | |
137 | ||
dd67d32d TH |
138 | /** |
139 | * freezer_should_skip - whether to skip a task when determining frozen | |
140 | * state is reached | |
141 | * @p: task in quesion | |
142 | * | |
143 | * This function is used by freezers after establishing %true freezing() to | |
144 | * test whether a task should be skipped when determining the target frozen | |
145 | * state is reached. IOW, if this function returns %true, @p is considered | |
146 | * frozen enough. | |
ba96a0c8 | 147 | */ |
dd67d32d | 148 | static inline bool freezer_should_skip(struct task_struct *p) |
ba96a0c8 | 149 | { |
dd67d32d TH |
150 | /* |
151 | * The following smp_mb() paired with the one in freezer_count() | |
152 | * ensures that either freezer_count() sees %true freezing() or we | |
153 | * see cleared %PF_FREEZER_SKIP and return %false. This makes it | |
154 | * impossible for a task to slip frozen state testing after | |
155 | * clearing %PF_FREEZER_SKIP. | |
156 | */ | |
157 | smp_mb(); | |
158 | return p->flags & PF_FREEZER_SKIP; | |
ba96a0c8 | 159 | } |
ff39593a | 160 | |
d310310c | 161 | /* |
8ee492d6 | 162 | * These functions are intended to be used whenever you want allow a sleeping |
5d8f72b5 ON |
163 | * task to be frozen. Note that neither return any clear indication of |
164 | * whether a freeze event happened while in this function. | |
d310310c JL |
165 | */ |
166 | ||
167 | /* Like schedule(), but should not block the freezer. */ | |
8ee492d6 CC |
168 | static inline void freezable_schedule(void) |
169 | { | |
170 | freezer_do_not_count(); | |
171 | schedule(); | |
172 | freezer_count(); | |
173 | } | |
d310310c | 174 | |
416ad3c9 | 175 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
8ee492d6 CC |
176 | static inline void freezable_schedule_unsafe(void) |
177 | { | |
178 | freezer_do_not_count(); | |
179 | schedule(); | |
180 | freezer_count_unsafe(); | |
181 | } | |
416ad3c9 | 182 | |
dd5ec0f4 CC |
183 | /* |
184 | * Like freezable_schedule_timeout(), but should not block the freezer. Do not | |
185 | * call this with locks held. | |
186 | */ | |
187 | static inline long freezable_schedule_timeout(long timeout) | |
188 | { | |
189 | long __retval; | |
190 | freezer_do_not_count(); | |
191 | __retval = schedule_timeout(timeout); | |
192 | freezer_count(); | |
193 | return __retval; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Like schedule_timeout_interruptible(), but should not block the freezer. Do not | |
198 | * call this with locks held. | |
199 | */ | |
200 | static inline long freezable_schedule_timeout_interruptible(long timeout) | |
201 | { | |
202 | long __retval; | |
203 | freezer_do_not_count(); | |
204 | __retval = schedule_timeout_interruptible(timeout); | |
205 | freezer_count(); | |
206 | return __retval; | |
207 | } | |
208 | ||
d310310c | 209 | /* Like schedule_timeout_killable(), but should not block the freezer. */ |
8ee492d6 CC |
210 | static inline long freezable_schedule_timeout_killable(long timeout) |
211 | { | |
212 | long __retval; | |
213 | freezer_do_not_count(); | |
214 | __retval = schedule_timeout_killable(timeout); | |
215 | freezer_count(); | |
216 | return __retval; | |
217 | } | |
d310310c | 218 | |
416ad3c9 | 219 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
8ee492d6 CC |
220 | static inline long freezable_schedule_timeout_killable_unsafe(long timeout) |
221 | { | |
222 | long __retval; | |
223 | freezer_do_not_count(); | |
224 | __retval = schedule_timeout_killable(timeout); | |
225 | freezer_count_unsafe(); | |
226 | return __retval; | |
227 | } | |
416ad3c9 | 228 | |
dd5ec0f4 CC |
229 | /* |
230 | * Like schedule_hrtimeout_range(), but should not block the freezer. Do not | |
231 | * call this with locks held. | |
232 | */ | |
233 | static inline int freezable_schedule_hrtimeout_range(ktime_t *expires, | |
234 | unsigned long delta, const enum hrtimer_mode mode) | |
235 | { | |
236 | int __retval; | |
237 | freezer_do_not_count(); | |
238 | __retval = schedule_hrtimeout_range(expires, delta, mode); | |
239 | freezer_count(); | |
240 | return __retval; | |
241 | } | |
242 | ||
e42837bc | 243 | /* |
f06ac72e JL |
244 | * Freezer-friendly wrappers around wait_event_interruptible(), |
245 | * wait_event_killable() and wait_event_interruptible_timeout(), originally | |
246 | * defined in <linux/wait.h> | |
e42837bc RW |
247 | */ |
248 | ||
f06ac72e JL |
249 | #define wait_event_freezekillable(wq, condition) \ |
250 | ({ \ | |
251 | int __retval; \ | |
6f35c4ab ON |
252 | freezer_do_not_count(); \ |
253 | __retval = wait_event_killable(wq, (condition)); \ | |
254 | freezer_count(); \ | |
f06ac72e JL |
255 | __retval; \ |
256 | }) | |
257 | ||
5853cc2a CC |
258 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
259 | #define wait_event_freezekillable_unsafe(wq, condition) \ | |
260 | ({ \ | |
261 | int __retval; \ | |
262 | freezer_do_not_count(); \ | |
263 | __retval = wait_event_killable(wq, (condition)); \ | |
264 | freezer_count_unsafe(); \ | |
265 | __retval; \ | |
266 | }) | |
267 | ||
e42837bc RW |
268 | #define wait_event_freezable(wq, condition) \ |
269 | ({ \ | |
270 | int __retval; \ | |
b0123586 CC |
271 | freezer_do_not_count(); \ |
272 | __retval = wait_event_interruptible(wq, (condition)); \ | |
273 | freezer_count(); \ | |
e42837bc RW |
274 | __retval; \ |
275 | }) | |
276 | ||
e42837bc RW |
277 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
278 | ({ \ | |
279 | long __retval = timeout; \ | |
b0123586 CC |
280 | freezer_do_not_count(); \ |
281 | __retval = wait_event_interruptible_timeout(wq, (condition), \ | |
282 | __retval); \ | |
283 | freezer_count(); \ | |
e42837bc RW |
284 | __retval; \ |
285 | }) | |
24b7ead3 | 286 | |
dd5ec0f4 CC |
287 | #define wait_event_freezable_exclusive(wq, condition) \ |
288 | ({ \ | |
289 | int __retval; \ | |
290 | freezer_do_not_count(); \ | |
291 | __retval = wait_event_interruptible_exclusive(wq, condition); \ | |
292 | freezer_count(); \ | |
293 | __retval; \ | |
294 | }) | |
295 | ||
296 | ||
8174f150 | 297 | #else /* !CONFIG_FREEZER */ |
948246f7 | 298 | static inline bool frozen(struct task_struct *p) { return false; } |
a3201227 | 299 | static inline bool freezing(struct task_struct *p) { return false; } |
62c9ea6b | 300 | static inline void __thaw_task(struct task_struct *t) {} |
7dfb7103 | 301 | |
8a32c441 | 302 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } |
2aede851 RW |
303 | static inline int freeze_processes(void) { return -ENOSYS; } |
304 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } | |
7dfb7103 | 305 | static inline void thaw_processes(void) {} |
181e9bde | 306 | static inline void thaw_kernel_threads(void) {} |
7dfb7103 | 307 | |
e5f57621 | 308 | static inline bool try_to_freeze_nowarn(void) { return false; } |
a0acae0e | 309 | static inline bool try_to_freeze(void) { return false; } |
7dfb7103 | 310 | |
ba96a0c8 RW |
311 | static inline void freezer_do_not_count(void) {} |
312 | static inline void freezer_count(void) {} | |
313 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 314 | static inline void set_freezable(void) {} |
e42837bc | 315 | |
d310310c JL |
316 | #define freezable_schedule() schedule() |
317 | ||
416ad3c9 CC |
318 | #define freezable_schedule_unsafe() schedule() |
319 | ||
dd5ec0f4 CC |
320 | #define freezable_schedule_timeout(timeout) schedule_timeout(timeout) |
321 | ||
322 | #define freezable_schedule_timeout_interruptible(timeout) \ | |
323 | schedule_timeout_interruptible(timeout) | |
324 | ||
d310310c JL |
325 | #define freezable_schedule_timeout_killable(timeout) \ |
326 | schedule_timeout_killable(timeout) | |
327 | ||
416ad3c9 CC |
328 | #define freezable_schedule_timeout_killable_unsafe(timeout) \ |
329 | schedule_timeout_killable(timeout) | |
330 | ||
dd5ec0f4 CC |
331 | #define freezable_schedule_hrtimeout_range(expires, delta, mode) \ |
332 | schedule_hrtimeout_range(expires, delta, mode) | |
333 | ||
e42837bc RW |
334 | #define wait_event_freezable(wq, condition) \ |
335 | wait_event_interruptible(wq, condition) | |
336 | ||
337 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
338 | wait_event_interruptible_timeout(wq, condition, timeout) | |
339 | ||
dd5ec0f4 CC |
340 | #define wait_event_freezable_exclusive(wq, condition) \ |
341 | wait_event_interruptible_exclusive(wq, condition) | |
342 | ||
e0c8ea1a SF |
343 | #define wait_event_freezekillable(wq, condition) \ |
344 | wait_event_killable(wq, condition) | |
345 | ||
5853cc2a CC |
346 | #define wait_event_freezekillable_unsafe(wq, condition) \ |
347 | wait_event_killable(wq, condition) | |
348 | ||
8174f150 | 349 | #endif /* !CONFIG_FREEZER */ |
83144186 RW |
350 | |
351 | #endif /* FREEZER_H_INCLUDED */ |