| 1 | /* Freezer declarations */ |
| 2 | |
| 3 | #ifndef FREEZER_H_INCLUDED |
| 4 | #define FREEZER_H_INCLUDED |
| 5 | |
| 6 | #include <linux/sched.h> |
| 7 | #include <linux/wait.h> |
| 8 | #include <linux/atomic.h> |
| 9 | |
| 10 | #ifdef CONFIG_FREEZER |
| 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 | |
| 15 | /* |
| 16 | * Check if a process has been frozen |
| 17 | */ |
| 18 | static inline bool frozen(struct task_struct *p) |
| 19 | { |
| 20 | return p->flags & PF_FROZEN; |
| 21 | } |
| 22 | |
| 23 | extern bool freezing_slow_path(struct task_struct *p); |
| 24 | |
| 25 | /* |
| 26 | * Check if there is a request to freeze a process |
| 27 | */ |
| 28 | static inline bool freezing(struct task_struct *p) |
| 29 | { |
| 30 | if (likely(!atomic_read(&system_freezing_cnt))) |
| 31 | return false; |
| 32 | return freezing_slow_path(p); |
| 33 | } |
| 34 | |
| 35 | /* Takes and releases task alloc lock using task_lock() */ |
| 36 | extern void __thaw_task(struct task_struct *t); |
| 37 | |
| 38 | extern bool __refrigerator(bool check_kthr_stop); |
| 39 | extern int freeze_processes(void); |
| 40 | extern int freeze_kernel_threads(void); |
| 41 | extern void thaw_processes(void); |
| 42 | extern void thaw_kernel_threads(void); |
| 43 | |
| 44 | static inline bool try_to_freeze(void) |
| 45 | { |
| 46 | might_sleep(); |
| 47 | if (likely(!freezing(current))) |
| 48 | return false; |
| 49 | return __refrigerator(false); |
| 50 | } |
| 51 | |
| 52 | extern bool freeze_task(struct task_struct *p); |
| 53 | extern bool set_freezable(void); |
| 54 | |
| 55 | #ifdef CONFIG_CGROUP_FREEZER |
| 56 | extern bool cgroup_freezing(struct task_struct *task); |
| 57 | #else /* !CONFIG_CGROUP_FREEZER */ |
| 58 | static inline bool cgroup_freezing(struct task_struct *task) |
| 59 | { |
| 60 | return false; |
| 61 | } |
| 62 | #endif /* !CONFIG_CGROUP_FREEZER */ |
| 63 | |
| 64 | /* |
| 65 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it |
| 66 | * calls wait_for_completion(&vfork) and reset right after it returns from this |
| 67 | * function. Next, the parent should call try_to_freeze() to freeze itself |
| 68 | * appropriately in case the child has exited before the freezing of tasks is |
| 69 | * complete. However, we don't want kernel threads to be frozen in unexpected |
| 70 | * places, so we allow them to block freeze_processes() instead or to set |
| 71 | * PF_NOFREEZE if needed. Fortunately, in the ____call_usermodehelper() case the |
| 72 | * parent won't really block freeze_processes(), since ____call_usermodehelper() |
| 73 | * (the child) does a little before exec/exit and it can't be frozen before |
| 74 | * waking up the parent. |
| 75 | */ |
| 76 | |
| 77 | |
| 78 | /* Tell the freezer not to count the current task as freezable. */ |
| 79 | static inline void freezer_do_not_count(void) |
| 80 | { |
| 81 | current->flags |= PF_FREEZER_SKIP; |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * Tell the freezer to count the current task as freezable again and try to |
| 86 | * freeze it. |
| 87 | */ |
| 88 | static inline void freezer_count(void) |
| 89 | { |
| 90 | current->flags &= ~PF_FREEZER_SKIP; |
| 91 | try_to_freeze(); |
| 92 | } |
| 93 | |
| 94 | /* |
| 95 | * Check if the task should be counted as freezable by the freezer |
| 96 | */ |
| 97 | static inline int freezer_should_skip(struct task_struct *p) |
| 98 | { |
| 99 | return !!(p->flags & PF_FREEZER_SKIP); |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * These macros are intended to be used whenever you want allow a task that's |
| 104 | * sleeping in TASK_UNINTERRUPTIBLE or TASK_KILLABLE state to be frozen. Note |
| 105 | * that neither return any clear indication of whether a freeze event happened |
| 106 | * while in this function. |
| 107 | */ |
| 108 | |
| 109 | /* Like schedule(), but should not block the freezer. */ |
| 110 | #define freezable_schedule() \ |
| 111 | ({ \ |
| 112 | freezer_do_not_count(); \ |
| 113 | schedule(); \ |
| 114 | freezer_count(); \ |
| 115 | }) |
| 116 | |
| 117 | /* Like schedule_timeout_killable(), but should not block the freezer. */ |
| 118 | #define freezable_schedule_timeout_killable(timeout) \ |
| 119 | ({ \ |
| 120 | long __retval; \ |
| 121 | freezer_do_not_count(); \ |
| 122 | __retval = schedule_timeout_killable(timeout); \ |
| 123 | freezer_count(); \ |
| 124 | __retval; \ |
| 125 | }) |
| 126 | |
| 127 | /* |
| 128 | * Freezer-friendly wrappers around wait_event_interruptible(), |
| 129 | * wait_event_killable() and wait_event_interruptible_timeout(), originally |
| 130 | * defined in <linux/wait.h> |
| 131 | */ |
| 132 | |
| 133 | #define wait_event_freezekillable(wq, condition) \ |
| 134 | ({ \ |
| 135 | int __retval; \ |
| 136 | freezer_do_not_count(); \ |
| 137 | __retval = wait_event_killable(wq, (condition)); \ |
| 138 | freezer_count(); \ |
| 139 | __retval; \ |
| 140 | }) |
| 141 | |
| 142 | #define wait_event_freezable(wq, condition) \ |
| 143 | ({ \ |
| 144 | int __retval; \ |
| 145 | for (;;) { \ |
| 146 | __retval = wait_event_interruptible(wq, \ |
| 147 | (condition) || freezing(current)); \ |
| 148 | if (__retval || (condition)) \ |
| 149 | break; \ |
| 150 | try_to_freeze(); \ |
| 151 | } \ |
| 152 | __retval; \ |
| 153 | }) |
| 154 | |
| 155 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
| 156 | ({ \ |
| 157 | long __retval = timeout; \ |
| 158 | for (;;) { \ |
| 159 | __retval = wait_event_interruptible_timeout(wq, \ |
| 160 | (condition) || freezing(current), \ |
| 161 | __retval); \ |
| 162 | if (__retval <= 0 || (condition)) \ |
| 163 | break; \ |
| 164 | try_to_freeze(); \ |
| 165 | } \ |
| 166 | __retval; \ |
| 167 | }) |
| 168 | |
| 169 | #else /* !CONFIG_FREEZER */ |
| 170 | static inline bool frozen(struct task_struct *p) { return false; } |
| 171 | static inline bool freezing(struct task_struct *p) { return false; } |
| 172 | static inline void __thaw_task(struct task_struct *t) {} |
| 173 | |
| 174 | static inline bool __refrigerator(bool check_kthr_stop) { return false; } |
| 175 | static inline int freeze_processes(void) { return -ENOSYS; } |
| 176 | static inline int freeze_kernel_threads(void) { return -ENOSYS; } |
| 177 | static inline void thaw_processes(void) {} |
| 178 | static inline void thaw_kernel_threads(void) {} |
| 179 | |
| 180 | static inline bool try_to_freeze(void) { return false; } |
| 181 | |
| 182 | static inline void freezer_do_not_count(void) {} |
| 183 | static inline void freezer_count(void) {} |
| 184 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } |
| 185 | static inline void set_freezable(void) {} |
| 186 | |
| 187 | #define freezable_schedule() schedule() |
| 188 | |
| 189 | #define freezable_schedule_timeout_killable(timeout) \ |
| 190 | schedule_timeout_killable(timeout) |
| 191 | |
| 192 | #define wait_event_freezable(wq, condition) \ |
| 193 | wait_event_interruptible(wq, condition) |
| 194 | |
| 195 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
| 196 | wait_event_interruptible_timeout(wq, condition, timeout) |
| 197 | |
| 198 | #define wait_event_freezekillable(wq, condition) \ |
| 199 | wait_event_killable(wq, condition) |
| 200 | |
| 201 | #endif /* !CONFIG_FREEZER */ |
| 202 | |
| 203 | #endif /* FREEZER_H_INCLUDED */ |