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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
7dfb7103 NC |
2 | /* Freezer declarations */ |
3 | ||
83144186 RW |
4 | #ifndef FREEZER_H_INCLUDED |
5 | #define FREEZER_H_INCLUDED | |
6 | ||
0f9548ca | 7 | #include <linux/debug_locks.h> |
5c543eff | 8 | #include <linux/sched.h> |
e42837bc | 9 | #include <linux/wait.h> |
a3201227 | 10 | #include <linux/atomic.h> |
5c543eff | 11 | |
8174f150 | 12 | #ifdef CONFIG_FREEZER |
a3201227 TH |
13 | extern atomic_t system_freezing_cnt; /* nr of freezing conds in effect */ |
14 | extern bool pm_freezing; /* PM freezing in effect */ | |
15 | extern bool pm_nosig_freezing; /* PM nosig freezing in effect */ | |
16 | ||
957d1282 LF |
17 | /* |
18 | * Timeout for stopping processes | |
19 | */ | |
20 | extern unsigned int freeze_timeout_msecs; | |
21 | ||
7dfb7103 NC |
22 | /* |
23 | * Check if a process has been frozen | |
24 | */ | |
948246f7 | 25 | static inline bool frozen(struct task_struct *p) |
7dfb7103 NC |
26 | { |
27 | return p->flags & PF_FROZEN; | |
28 | } | |
29 | ||
a3201227 | 30 | extern bool freezing_slow_path(struct task_struct *p); |
7dfb7103 NC |
31 | |
32 | /* | |
a3201227 | 33 | * Check if there is a request to freeze a process |
7dfb7103 | 34 | */ |
a3201227 | 35 | static inline bool freezing(struct task_struct *p) |
7dfb7103 | 36 | { |
a3201227 TH |
37 | if (likely(!atomic_read(&system_freezing_cnt))) |
38 | return false; | |
39 | return freezing_slow_path(p); | |
7dfb7103 NC |
40 | } |
41 | ||
dc52ddc0 | 42 | /* Takes and releases task alloc lock using task_lock() */ |
a5be2d0d | 43 | extern void __thaw_task(struct task_struct *t); |
7dfb7103 | 44 | |
8a32c441 | 45 | extern bool __refrigerator(bool check_kthr_stop); |
7dfb7103 | 46 | extern int freeze_processes(void); |
2aede851 | 47 | extern int freeze_kernel_threads(void); |
a9b6f562 | 48 | extern void thaw_processes(void); |
181e9bde | 49 | extern void thaw_kernel_threads(void); |
7dfb7103 | 50 | |
416ad3c9 CC |
51 | /* |
52 | * DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION | |
53 | * If try_to_freeze causes a lockdep warning it means the caller may deadlock | |
54 | */ | |
55 | static inline bool try_to_freeze_unsafe(void) | |
7dfb7103 | 56 | { |
a0acae0e TH |
57 | might_sleep(); |
58 | if (likely(!freezing(current))) | |
59 | return false; | |
8a32c441 | 60 | return __refrigerator(false); |
7dfb7103 | 61 | } |
ff39593a | 62 | |
416ad3c9 CC |
63 | static inline bool try_to_freeze(void) |
64 | { | |
0f9548ca MSB |
65 | if (!(current->flags & PF_NOFREEZE)) |
66 | debug_check_no_locks_held(); | |
416ad3c9 CC |
67 | return try_to_freeze_unsafe(); |
68 | } | |
69 | ||
839e3407 | 70 | extern bool freeze_task(struct task_struct *p); |
34b087e4 | 71 | extern bool set_freezable(void); |
8174f150 | 72 | |
dc52ddc0 | 73 | #ifdef CONFIG_CGROUP_FREEZER |
22b4e111 | 74 | extern bool cgroup_freezing(struct task_struct *task); |
dc52ddc0 | 75 | #else /* !CONFIG_CGROUP_FREEZER */ |
22b4e111 | 76 | static inline bool cgroup_freezing(struct task_struct *task) |
5a7aadfe | 77 | { |
22b4e111 | 78 | return false; |
5a7aadfe | 79 | } |
dc52ddc0 MH |
80 | #endif /* !CONFIG_CGROUP_FREEZER */ |
81 | ||
ba96a0c8 RW |
82 | /* |
83 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
84 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
85 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
86 | * appropriately in case the child has exited before the freezing of tasks is | |
87 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
88 | * places, so we allow them to block freeze_processes() instead or to set | |
467de1fc SB |
89 | * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the |
90 | * parent won't really block freeze_processes(), since ____call_usermodehelper() | |
91 | * (the child) does a little before exec/exit and it can't be frozen before | |
92 | * waking up the parent. | |
ba96a0c8 RW |
93 | */ |
94 | ||
467de1fc | 95 | |
dd67d32d TH |
96 | /** |
97 | * freezer_do_not_count - tell freezer to ignore %current | |
98 | * | |
99 | * Tell freezers to ignore the current task when determining whether the | |
100 | * target frozen state is reached. IOW, the current task will be | |
101 | * considered frozen enough by freezers. | |
102 | * | |
103 | * The caller shouldn't do anything which isn't allowed for a frozen task | |
104 | * until freezer_cont() is called. Usually, freezer[_do_not]_count() pair | |
105 | * wrap a scheduling operation and nothing much else. | |
106 | */ | |
ba96a0c8 RW |
107 | static inline void freezer_do_not_count(void) |
108 | { | |
467de1fc | 109 | current->flags |= PF_FREEZER_SKIP; |
ba96a0c8 RW |
110 | } |
111 | ||
dd67d32d TH |
112 | /** |
113 | * freezer_count - tell freezer to stop ignoring %current | |
114 | * | |
115 | * Undo freezer_do_not_count(). It tells freezers that %current should be | |
116 | * considered again and tries to freeze if freezing condition is already in | |
117 | * effect. | |
ba96a0c8 RW |
118 | */ |
119 | static inline void freezer_count(void) | |
120 | { | |
467de1fc | 121 | current->flags &= ~PF_FREEZER_SKIP; |
dd67d32d TH |
122 | /* |
123 | * If freezing is in progress, the following paired with smp_mb() | |
124 | * in freezer_should_skip() ensures that either we see %true | |
125 | * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP. | |
126 | */ | |
127 | smp_mb(); | |
467de1fc | 128 | try_to_freeze(); |
ba96a0c8 RW |
129 | } |
130 | ||
416ad3c9 CC |
131 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
132 | static inline void freezer_count_unsafe(void) | |
133 | { | |
134 | current->flags &= ~PF_FREEZER_SKIP; | |
135 | smp_mb(); | |
136 | try_to_freeze_unsafe(); | |
137 | } | |
138 | ||
dd67d32d TH |
139 | /** |
140 | * freezer_should_skip - whether to skip a task when determining frozen | |
141 | * state is reached | |
142 | * @p: task in quesion | |
143 | * | |
144 | * This function is used by freezers after establishing %true freezing() to | |
145 | * test whether a task should be skipped when determining the target frozen | |
146 | * state is reached. IOW, if this function returns %true, @p is considered | |
147 | * frozen enough. | |
ba96a0c8 | 148 | */ |
dd67d32d | 149 | static inline bool freezer_should_skip(struct task_struct *p) |
ba96a0c8 | 150 | { |
dd67d32d TH |
151 | /* |
152 | * The following smp_mb() paired with the one in freezer_count() | |
153 | * ensures that either freezer_count() sees %true freezing() or we | |
154 | * see cleared %PF_FREEZER_SKIP and return %false. This makes it | |
155 | * impossible for a task to slip frozen state testing after | |
156 | * clearing %PF_FREEZER_SKIP. | |
157 | */ | |
158 | smp_mb(); | |
159 | return p->flags & PF_FREEZER_SKIP; | |
ba96a0c8 | 160 | } |
ff39593a | 161 | |
d310310c | 162 | /* |
8ee492d6 | 163 | * These functions are intended to be used whenever you want allow a sleeping |
5d8f72b5 ON |
164 | * task to be frozen. Note that neither return any clear indication of |
165 | * whether a freeze event happened while in this function. | |
d310310c JL |
166 | */ |
167 | ||
168 | /* Like schedule(), but should not block the freezer. */ | |
8ee492d6 CC |
169 | static inline void freezable_schedule(void) |
170 | { | |
171 | freezer_do_not_count(); | |
172 | schedule(); | |
173 | freezer_count(); | |
174 | } | |
d310310c | 175 | |
416ad3c9 | 176 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
8ee492d6 CC |
177 | static inline void freezable_schedule_unsafe(void) |
178 | { | |
179 | freezer_do_not_count(); | |
180 | schedule(); | |
181 | freezer_count_unsafe(); | |
182 | } | |
416ad3c9 | 183 | |
dd5ec0f4 | 184 | /* |
2dd9789c | 185 | * Like schedule_timeout(), but should not block the freezer. Do not |
dd5ec0f4 CC |
186 | * call this with locks held. |
187 | */ | |
188 | static inline long freezable_schedule_timeout(long timeout) | |
189 | { | |
190 | long __retval; | |
191 | freezer_do_not_count(); | |
192 | __retval = schedule_timeout(timeout); | |
193 | freezer_count(); | |
194 | return __retval; | |
195 | } | |
196 | ||
197 | /* | |
198 | * Like schedule_timeout_interruptible(), but should not block the freezer. Do not | |
199 | * call this with locks held. | |
200 | */ | |
201 | static inline long freezable_schedule_timeout_interruptible(long timeout) | |
202 | { | |
203 | long __retval; | |
204 | freezer_do_not_count(); | |
205 | __retval = schedule_timeout_interruptible(timeout); | |
206 | freezer_count(); | |
207 | return __retval; | |
208 | } | |
209 | ||
59679d99 HZ |
210 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
211 | static inline long freezable_schedule_timeout_interruptible_unsafe(long timeout) | |
212 | { | |
213 | long __retval; | |
214 | ||
215 | freezer_do_not_count(); | |
216 | __retval = schedule_timeout_interruptible(timeout); | |
217 | freezer_count_unsafe(); | |
218 | return __retval; | |
219 | } | |
220 | ||
d310310c | 221 | /* Like schedule_timeout_killable(), but should not block the freezer. */ |
8ee492d6 CC |
222 | static inline long freezable_schedule_timeout_killable(long timeout) |
223 | { | |
224 | long __retval; | |
225 | freezer_do_not_count(); | |
226 | __retval = schedule_timeout_killable(timeout); | |
227 | freezer_count(); | |
228 | return __retval; | |
229 | } | |
d310310c | 230 | |
416ad3c9 | 231 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
8ee492d6 CC |
232 | static inline long freezable_schedule_timeout_killable_unsafe(long timeout) |
233 | { | |
234 | long __retval; | |
235 | freezer_do_not_count(); | |
236 | __retval = schedule_timeout_killable(timeout); | |
237 | freezer_count_unsafe(); | |
238 | return __retval; | |
239 | } | |
416ad3c9 | 240 | |
dd5ec0f4 CC |
241 | /* |
242 | * Like schedule_hrtimeout_range(), but should not block the freezer. Do not | |
243 | * call this with locks held. | |
244 | */ | |
245 | static inline int freezable_schedule_hrtimeout_range(ktime_t *expires, | |
da8b44d5 | 246 | u64 delta, const enum hrtimer_mode mode) |
dd5ec0f4 CC |
247 | { |
248 | int __retval; | |
249 | freezer_do_not_count(); | |
250 | __retval = schedule_hrtimeout_range(expires, delta, mode); | |
251 | freezer_count(); | |
252 | return __retval; | |
253 | } | |
254 | ||
e42837bc | 255 | /* |
f06ac72e JL |
256 | * Freezer-friendly wrappers around wait_event_interruptible(), |
257 | * wait_event_killable() and wait_event_interruptible_timeout(), originally | |
258 | * defined in <linux/wait.h> | |
e42837bc RW |
259 | */ |
260 | ||
5853cc2a CC |
261 | /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ |
262 | #define wait_event_freezekillable_unsafe(wq, condition) \ | |
263 | ({ \ | |
264 | int __retval; \ | |
265 | freezer_do_not_count(); \ | |
266 | __retval = wait_event_killable(wq, (condition)); \ | |
267 | freezer_count_unsafe(); \ | |
268 | __retval; \ | |
269 | }) | |
270 | ||
8174f150 | 271 | #else /* !CONFIG_FREEZER */ |
948246f7 | 272 | static inline bool frozen(struct task_struct *p) { return false; } |
a3201227 | 273 | static inline bool freezing(struct task_struct *p) { return false; } |
62c9ea6b | 274 | static inline void __thaw_task(struct task_struct *t) {} |
7dfb7103 | 275 | |
8a32c441 | 276 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } |
2aede851 RW |
277 | static inline int freeze_processes(void) { return -ENOSYS; } |
278 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } | |
7dfb7103 | 279 | static inline void thaw_processes(void) {} |
181e9bde | 280 | static inline void thaw_kernel_threads(void) {} |
7dfb7103 | 281 | |
a0acae0e | 282 | static inline bool try_to_freeze(void) { return false; } |
7dfb7103 | 283 | |
ba96a0c8 RW |
284 | static inline void freezer_do_not_count(void) {} |
285 | static inline void freezer_count(void) {} | |
286 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 287 | static inline void set_freezable(void) {} |
e42837bc | 288 | |
d310310c JL |
289 | #define freezable_schedule() schedule() |
290 | ||
416ad3c9 CC |
291 | #define freezable_schedule_unsafe() schedule() |
292 | ||
dd5ec0f4 CC |
293 | #define freezable_schedule_timeout(timeout) schedule_timeout(timeout) |
294 | ||
295 | #define freezable_schedule_timeout_interruptible(timeout) \ | |
296 | schedule_timeout_interruptible(timeout) | |
297 | ||
59679d99 HZ |
298 | #define freezable_schedule_timeout_interruptible_unsafe(timeout) \ |
299 | schedule_timeout_interruptible(timeout) | |
300 | ||
d310310c JL |
301 | #define freezable_schedule_timeout_killable(timeout) \ |
302 | schedule_timeout_killable(timeout) | |
303 | ||
416ad3c9 CC |
304 | #define freezable_schedule_timeout_killable_unsafe(timeout) \ |
305 | schedule_timeout_killable(timeout) | |
306 | ||
dd5ec0f4 CC |
307 | #define freezable_schedule_hrtimeout_range(expires, delta, mode) \ |
308 | schedule_hrtimeout_range(expires, delta, mode) | |
309 | ||
5853cc2a CC |
310 | #define wait_event_freezekillable_unsafe(wq, condition) \ |
311 | wait_event_killable(wq, condition) | |
312 | ||
8174f150 | 313 | #endif /* !CONFIG_FREEZER */ |
83144186 RW |
314 | |
315 | #endif /* FREEZER_H_INCLUDED */ |