| 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 | |
| 9 | #ifdef CONFIG_FREEZER |
| 10 | /* |
| 11 | * Check if a process has been frozen |
| 12 | */ |
| 13 | static inline int frozen(struct task_struct *p) |
| 14 | { |
| 15 | return p->flags & PF_FROZEN; |
| 16 | } |
| 17 | |
| 18 | /* |
| 19 | * Check if there is a request to freeze a process |
| 20 | */ |
| 21 | static inline int freezing(struct task_struct *p) |
| 22 | { |
| 23 | return test_tsk_thread_flag(p, TIF_FREEZE); |
| 24 | } |
| 25 | |
| 26 | /* |
| 27 | * Request that a process be frozen |
| 28 | */ |
| 29 | static inline void set_freeze_flag(struct task_struct *p) |
| 30 | { |
| 31 | set_tsk_thread_flag(p, TIF_FREEZE); |
| 32 | } |
| 33 | |
| 34 | /* |
| 35 | * Sometimes we may need to cancel the previous 'freeze' request |
| 36 | */ |
| 37 | static inline void clear_freeze_flag(struct task_struct *p) |
| 38 | { |
| 39 | clear_tsk_thread_flag(p, TIF_FREEZE); |
| 40 | } |
| 41 | |
| 42 | static inline bool should_send_signal(struct task_struct *p) |
| 43 | { |
| 44 | return !(p->flags & PF_FREEZER_NOSIG); |
| 45 | } |
| 46 | |
| 47 | /* Takes and releases task alloc lock using task_lock() */ |
| 48 | extern int thaw_process(struct task_struct *p); |
| 49 | |
| 50 | extern void refrigerator(void); |
| 51 | extern int freeze_processes(void); |
| 52 | extern int freeze_kernel_threads(void); |
| 53 | extern void thaw_processes(void); |
| 54 | |
| 55 | static inline int try_to_freeze(void) |
| 56 | { |
| 57 | if (freezing(current)) { |
| 58 | refrigerator(); |
| 59 | return 1; |
| 60 | } else |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | extern bool freeze_task(struct task_struct *p, bool sig_only); |
| 65 | extern void cancel_freezing(struct task_struct *p); |
| 66 | |
| 67 | #ifdef CONFIG_CGROUP_FREEZER |
| 68 | extern int cgroup_freezing_or_frozen(struct task_struct *task); |
| 69 | #else /* !CONFIG_CGROUP_FREEZER */ |
| 70 | static inline int cgroup_freezing_or_frozen(struct task_struct *task) |
| 71 | { |
| 72 | return 0; |
| 73 | } |
| 74 | #endif /* !CONFIG_CGROUP_FREEZER */ |
| 75 | |
| 76 | /* |
| 77 | * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it |
| 78 | * calls wait_for_completion(&vfork) and reset right after it returns from this |
| 79 | * function. Next, the parent should call try_to_freeze() to freeze itself |
| 80 | * appropriately in case the child has exited before the freezing of tasks is |
| 81 | * complete. However, we don't want kernel threads to be frozen in unexpected |
| 82 | * places, so we allow them to block freeze_processes() instead or to set |
| 83 | * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork |
| 84 | * parents. Fortunately, in the ____call_usermodehelper() case the parent won't |
| 85 | * really block freeze_processes(), since ____call_usermodehelper() (the child) |
| 86 | * does a little before exec/exit and it can't be frozen before waking up the |
| 87 | * parent. |
| 88 | */ |
| 89 | |
| 90 | /* |
| 91 | * If the current task is a user space one, tell the freezer not to count it as |
| 92 | * freezable. |
| 93 | */ |
| 94 | static inline void freezer_do_not_count(void) |
| 95 | { |
| 96 | if (current->mm) |
| 97 | current->flags |= PF_FREEZER_SKIP; |
| 98 | } |
| 99 | |
| 100 | /* |
| 101 | * If the current task is a user space one, tell the freezer to count it as |
| 102 | * freezable again and try to freeze it. |
| 103 | */ |
| 104 | static inline void freezer_count(void) |
| 105 | { |
| 106 | if (current->mm) { |
| 107 | current->flags &= ~PF_FREEZER_SKIP; |
| 108 | try_to_freeze(); |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | /* |
| 113 | * Check if the task should be counted as freezable by the freezer |
| 114 | */ |
| 115 | static inline int freezer_should_skip(struct task_struct *p) |
| 116 | { |
| 117 | return !!(p->flags & PF_FREEZER_SKIP); |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * Tell the freezer that the current task should be frozen by it |
| 122 | */ |
| 123 | static inline void set_freezable(void) |
| 124 | { |
| 125 | current->flags &= ~PF_NOFREEZE; |
| 126 | } |
| 127 | |
| 128 | /* |
| 129 | * Tell the freezer that the current task should be frozen by it and that it |
| 130 | * should send a fake signal to the task to freeze it. |
| 131 | */ |
| 132 | static inline void set_freezable_with_signal(void) |
| 133 | { |
| 134 | current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG); |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Freezer-friendly wrappers around wait_event_interruptible() and |
| 139 | * wait_event_interruptible_timeout(), originally defined in <linux/wait.h> |
| 140 | */ |
| 141 | |
| 142 | #define wait_event_freezable(wq, condition) \ |
| 143 | ({ \ |
| 144 | int __retval; \ |
| 145 | do { \ |
| 146 | __retval = wait_event_interruptible(wq, \ |
| 147 | (condition) || freezing(current)); \ |
| 148 | if (__retval && !freezing(current)) \ |
| 149 | break; \ |
| 150 | else if (!(condition)) \ |
| 151 | __retval = -ERESTARTSYS; \ |
| 152 | } while (try_to_freeze()); \ |
| 153 | __retval; \ |
| 154 | }) |
| 155 | |
| 156 | |
| 157 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
| 158 | ({ \ |
| 159 | long __retval = timeout; \ |
| 160 | do { \ |
| 161 | __retval = wait_event_interruptible_timeout(wq, \ |
| 162 | (condition) || freezing(current), \ |
| 163 | __retval); \ |
| 164 | } while (try_to_freeze()); \ |
| 165 | __retval; \ |
| 166 | }) |
| 167 | #else /* !CONFIG_FREEZER */ |
| 168 | static inline int frozen(struct task_struct *p) { return 0; } |
| 169 | static inline int freezing(struct task_struct *p) { return 0; } |
| 170 | static inline void set_freeze_flag(struct task_struct *p) {} |
| 171 | static inline void clear_freeze_flag(struct task_struct *p) {} |
| 172 | static inline int thaw_process(struct task_struct *p) { return 1; } |
| 173 | |
| 174 | static inline void refrigerator(void) {} |
| 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 | |
| 179 | static inline int try_to_freeze(void) { return 0; } |
| 180 | |
| 181 | static inline void freezer_do_not_count(void) {} |
| 182 | static inline void freezer_count(void) {} |
| 183 | static inline int freezer_should_skip(struct task_struct *p) { return 0; } |
| 184 | static inline void set_freezable(void) {} |
| 185 | static inline void set_freezable_with_signal(void) {} |
| 186 | |
| 187 | #define wait_event_freezable(wq, condition) \ |
| 188 | wait_event_interruptible(wq, condition) |
| 189 | |
| 190 | #define wait_event_freezable_timeout(wq, condition, timeout) \ |
| 191 | wait_event_interruptible_timeout(wq, condition, timeout) |
| 192 | |
| 193 | #endif /* !CONFIG_FREEZER */ |
| 194 | |
| 195 | #endif /* FREEZER_H_INCLUDED */ |