Commit | Line | Data |
---|---|---|
7dfb7103 NC |
1 | /* Freezer declarations */ |
2 | ||
83144186 RW |
3 | #ifndef FREEZER_H_INCLUDED |
4 | #define FREEZER_H_INCLUDED | |
5 | ||
6aa97070 | 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 | |
a0acae0e | 50 | static inline bool try_to_freeze(void) |
7dfb7103 | 51 | { |
6aa97070 MSB |
52 | if (!(current->flags & PF_NOFREEZE)) |
53 | debug_check_no_locks_held(); | |
a0acae0e TH |
54 | might_sleep(); |
55 | if (likely(!freezing(current))) | |
56 | return false; | |
8a32c441 | 57 | return __refrigerator(false); |
7dfb7103 | 58 | } |
ff39593a | 59 | |
839e3407 | 60 | extern bool freeze_task(struct task_struct *p); |
34b087e4 | 61 | extern bool set_freezable(void); |
8174f150 | 62 | |
dc52ddc0 | 63 | #ifdef CONFIG_CGROUP_FREEZER |
22b4e111 | 64 | extern bool cgroup_freezing(struct task_struct *task); |
dc52ddc0 | 65 | #else /* !CONFIG_CGROUP_FREEZER */ |
22b4e111 | 66 | static inline bool cgroup_freezing(struct task_struct *task) |
5a7aadfe | 67 | { |
22b4e111 | 68 | return false; |
5a7aadfe | 69 | } |
dc52ddc0 MH |
70 | #endif /* !CONFIG_CGROUP_FREEZER */ |
71 | ||
ba96a0c8 RW |
72 | /* |
73 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it | |
74 | * calls wait_for_completion(&vfork) and reset right after it returns from this | |
75 | * function. Next, the parent should call try_to_freeze() to freeze itself | |
76 | * appropriately in case the child has exited before the freezing of tasks is | |
77 | * complete. However, we don't want kernel threads to be frozen in unexpected | |
78 | * places, so we allow them to block freeze_processes() instead or to set | |
467de1fc SB |
79 | * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the |
80 | * parent won't really block freeze_processes(), since ____call_usermodehelper() | |
81 | * (the child) does a little before exec/exit and it can't be frozen before | |
82 | * waking up the parent. | |
ba96a0c8 RW |
83 | */ |
84 | ||
467de1fc | 85 | |
dd67d32d TH |
86 | /** |
87 | * freezer_do_not_count - tell freezer to ignore %current | |
88 | * | |
89 | * Tell freezers to ignore the current task when determining whether the | |
90 | * target frozen state is reached. IOW, the current task will be | |
91 | * considered frozen enough by freezers. | |
92 | * | |
93 | * The caller shouldn't do anything which isn't allowed for a frozen task | |
94 | * until freezer_cont() is called. Usually, freezer[_do_not]_count() pair | |
95 | * wrap a scheduling operation and nothing much else. | |
96 | */ | |
ba96a0c8 RW |
97 | static inline void freezer_do_not_count(void) |
98 | { | |
467de1fc | 99 | current->flags |= PF_FREEZER_SKIP; |
ba96a0c8 RW |
100 | } |
101 | ||
dd67d32d TH |
102 | /** |
103 | * freezer_count - tell freezer to stop ignoring %current | |
104 | * | |
105 | * Undo freezer_do_not_count(). It tells freezers that %current should be | |
106 | * considered again and tries to freeze if freezing condition is already in | |
107 | * effect. | |
ba96a0c8 RW |
108 | */ |
109 | static inline void freezer_count(void) | |
110 | { | |
467de1fc | 111 | current->flags &= ~PF_FREEZER_SKIP; |
dd67d32d TH |
112 | /* |
113 | * If freezing is in progress, the following paired with smp_mb() | |
114 | * in freezer_should_skip() ensures that either we see %true | |
115 | * freezing() or freezer_should_skip() sees !PF_FREEZER_SKIP. | |
116 | */ | |
117 | smp_mb(); | |
467de1fc | 118 | try_to_freeze(); |
ba96a0c8 RW |
119 | } |
120 | ||
dd67d32d TH |
121 | /** |
122 | * freezer_should_skip - whether to skip a task when determining frozen | |
123 | * state is reached | |
124 | * @p: task in quesion | |
125 | * | |
126 | * This function is used by freezers after establishing %true freezing() to | |
127 | * test whether a task should be skipped when determining the target frozen | |
128 | * state is reached. IOW, if this function returns %true, @p is considered | |
129 | * frozen enough. | |
ba96a0c8 | 130 | */ |
dd67d32d | 131 | static inline bool freezer_should_skip(struct task_struct *p) |
ba96a0c8 | 132 | { |
dd67d32d TH |
133 | /* |
134 | * The following smp_mb() paired with the one in freezer_count() | |
135 | * ensures that either freezer_count() sees %true freezing() or we | |
136 | * see cleared %PF_FREEZER_SKIP and return %false. This makes it | |
137 | * impossible for a task to slip frozen state testing after | |
138 | * clearing %PF_FREEZER_SKIP. | |
139 | */ | |
140 | smp_mb(); | |
141 | return p->flags & PF_FREEZER_SKIP; | |
ba96a0c8 | 142 | } |
ff39593a | 143 | |
d310310c | 144 | /* |
5d8f72b5 ON |
145 | * These macros are intended to be used whenever you want allow a sleeping |
146 | * task to be frozen. Note that neither return any clear indication of | |
147 | * whether a freeze event happened while in this function. | |
d310310c JL |
148 | */ |
149 | ||
150 | /* Like schedule(), but should not block the freezer. */ | |
151 | #define freezable_schedule() \ | |
152 | ({ \ | |
153 | freezer_do_not_count(); \ | |
154 | schedule(); \ | |
155 | freezer_count(); \ | |
156 | }) | |
157 | ||
158 | /* Like schedule_timeout_killable(), but should not block the freezer. */ | |
159 | #define freezable_schedule_timeout_killable(timeout) \ | |
160 | ({ \ | |
b3b73ec0 | 161 | long __retval; \ |
d310310c | 162 | freezer_do_not_count(); \ |
b3b73ec0 | 163 | __retval = schedule_timeout_killable(timeout); \ |
d310310c | 164 | freezer_count(); \ |
b3b73ec0 | 165 | __retval; \ |
d310310c JL |
166 | }) |
167 | ||
e42837bc | 168 | /* |
f06ac72e JL |
169 | * Freezer-friendly wrappers around wait_event_interruptible(), |
170 | * wait_event_killable() and wait_event_interruptible_timeout(), originally | |
171 | * defined in <linux/wait.h> | |
e42837bc RW |
172 | */ |
173 | ||
f06ac72e JL |
174 | #define wait_event_freezekillable(wq, condition) \ |
175 | ({ \ | |
176 | int __retval; \ | |
6f35c4ab ON |
177 | freezer_do_not_count(); \ |
178 | __retval = wait_event_killable(wq, (condition)); \ | |
179 | freezer_count(); \ | |
f06ac72e JL |
180 | __retval; \ |
181 | }) | |
182 | ||
e42837bc RW |
183 | #define wait_event_freezable(wq, condition) \ |
184 | ({ \ | |
185 | int __retval; \ | |
24b7ead3 | 186 | for (;;) { \ |
e42837bc RW |
187 | __retval = wait_event_interruptible(wq, \ |
188 | (condition) || freezing(current)); \ | |
24b7ead3 | 189 | if (__retval || (condition)) \ |
e42837bc | 190 | break; \ |
24b7ead3 ON |
191 | try_to_freeze(); \ |
192 | } \ | |
e42837bc RW |
193 | __retval; \ |
194 | }) | |
195 | ||
e42837bc RW |
196 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
197 | ({ \ | |
198 | long __retval = timeout; \ | |
24b7ead3 | 199 | for (;;) { \ |
e42837bc RW |
200 | __retval = wait_event_interruptible_timeout(wq, \ |
201 | (condition) || freezing(current), \ | |
202 | __retval); \ | |
24b7ead3 ON |
203 | if (__retval <= 0 || (condition)) \ |
204 | break; \ | |
205 | try_to_freeze(); \ | |
206 | } \ | |
e42837bc RW |
207 | __retval; \ |
208 | }) | |
24b7ead3 | 209 | |
8174f150 | 210 | #else /* !CONFIG_FREEZER */ |
948246f7 | 211 | static inline bool frozen(struct task_struct *p) { return false; } |
a3201227 | 212 | static inline bool freezing(struct task_struct *p) { return false; } |
62c9ea6b | 213 | static inline void __thaw_task(struct task_struct *t) {} |
7dfb7103 | 214 | |
8a32c441 | 215 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } |
2aede851 RW |
216 | static inline int freeze_processes(void) { return -ENOSYS; } |
217 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } | |
7dfb7103 | 218 | static inline void thaw_processes(void) {} |
181e9bde | 219 | static inline void thaw_kernel_threads(void) {} |
7dfb7103 | 220 | |
e5f57621 | 221 | static inline bool try_to_freeze_nowarn(void) { return false; } |
a0acae0e | 222 | static inline bool try_to_freeze(void) { return false; } |
7dfb7103 | 223 | |
ba96a0c8 RW |
224 | static inline void freezer_do_not_count(void) {} |
225 | static inline void freezer_count(void) {} | |
226 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } | |
83144186 | 227 | static inline void set_freezable(void) {} |
e42837bc | 228 | |
d310310c JL |
229 | #define freezable_schedule() schedule() |
230 | ||
231 | #define freezable_schedule_timeout_killable(timeout) \ | |
232 | schedule_timeout_killable(timeout) | |
233 | ||
e42837bc RW |
234 | #define wait_event_freezable(wq, condition) \ |
235 | wait_event_interruptible(wq, condition) | |
236 | ||
237 | #define wait_event_freezable_timeout(wq, condition, timeout) \ | |
238 | wait_event_interruptible_timeout(wq, condition, timeout) | |
239 | ||
e0c8ea1a SF |
240 | #define wait_event_freezekillable(wq, condition) \ |
241 | wait_event_killable(wq, condition) | |
242 | ||
8174f150 | 243 | #endif /* !CONFIG_FREEZER */ |
83144186 RW |
244 | |
245 | #endif /* FREEZER_H_INCLUDED */ |