diff options
Diffstat (limited to 'include/linux/freezer.h')
| -rw-r--r-- | include/linux/freezer.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/include/linux/freezer.h b/include/linux/freezer.h new file mode 100644 index 00000000..1effc8b5 --- /dev/null +++ b/include/linux/freezer.h @@ -0,0 +1,193 @@ +/* Freezer declarations */ + +#ifndef FREEZER_H_INCLUDED +#define FREEZER_H_INCLUDED + +#include <linux/sched.h> +#include <linux/wait.h> + +#ifdef CONFIG_FREEZER +/* + * Check if a process has been frozen + */ +static inline int frozen(struct task_struct *p) +{ + return p->flags & PF_FROZEN; +} + +/* + * Check if there is a request to freeze a process + */ +static inline int freezing(struct task_struct *p) +{ + return test_tsk_thread_flag(p, TIF_FREEZE); +} + +/* + * Request that a process be frozen + */ +static inline void set_freeze_flag(struct task_struct *p) +{ + set_tsk_thread_flag(p, TIF_FREEZE); +} + +/* + * Sometimes we may need to cancel the previous 'freeze' request + */ +static inline void clear_freeze_flag(struct task_struct *p) +{ + clear_tsk_thread_flag(p, TIF_FREEZE); +} + +static inline bool should_send_signal(struct task_struct *p) +{ + return !(p->flags & PF_FREEZER_NOSIG); +} + +/* Takes and releases task alloc lock using task_lock() */ +extern int thaw_process(struct task_struct *p); + +extern void refrigerator(void); +extern int freeze_processes(void); +extern void thaw_processes(void); + +static inline int try_to_freeze(void) +{ + if (freezing(current)) { + refrigerator(); + return 1; + } else + return 0; +} + +extern bool freeze_task(struct task_struct *p, bool sig_only); +extern void cancel_freezing(struct task_struct *p); + +#ifdef CONFIG_CGROUP_FREEZER +extern int cgroup_freezing_or_frozen(struct task_struct *task); +#else /* !CONFIG_CGROUP_FREEZER */ +static inline int cgroup_freezing_or_frozen(struct task_struct *task) +{ + return 0; +} +#endif /* !CONFIG_CGROUP_FREEZER */ + +/* + * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it + * calls wait_for_completion(&vfork) and reset right after it returns from this + * function. Next, the parent should call try_to_freeze() to freeze itself + * appropriately in case the child has exited before the freezing of tasks is + * complete. However, we don't want kernel threads to be frozen in unexpected + * places, so we allow them to block freeze_processes() instead or to set + * PF_NOFREEZE if needed and PF_FREEZER_SKIP is only set for userland vfork + * parents. Fortunately, in the ____call_usermodehelper() case the parent won't + * really block freeze_processes(), since ____call_usermodehelper() (the child) + * does a little before exec/exit and it can't be frozen before waking up the + * parent. + */ + +/* + * If the current task is a user space one, tell the freezer not to count it as + * freezable. + */ +static inline void freezer_do_not_count(void) +{ + if (current->mm) + current->flags |= PF_FREEZER_SKIP; +} + +/* + * If the current task is a user space one, tell the freezer to count it as + * freezable again and try to freeze it. + */ +static inline void freezer_count(void) +{ + if (current->mm) { + current->flags &= ~PF_FREEZER_SKIP; + try_to_freeze(); + } +} + +/* + * Check if the task should be counted as freezable by the freezer + */ +static inline int freezer_should_skip(struct task_struct *p) +{ + return !!(p->flags & PF_FREEZER_SKIP); +} + +/* + * Tell the freezer that the current task should be frozen by it + */ +static inline void set_freezable(void) +{ + current->flags &= ~PF_NOFREEZE; +} + +/* + * Tell the freezer that the current task should be frozen by it and that it + * should send a fake signal to the task to freeze it. + */ +static inline void set_freezable_with_signal(void) +{ + current->flags &= ~(PF_NOFREEZE | PF_FREEZER_NOSIG); +} + +/* + * Freezer-friendly wrappers around wait_event_interruptible() and + * wait_event_interruptible_timeout(), originally defined in <linux/wait.h> + */ + +#define wait_event_freezable(wq, condition) \ +({ \ + int __retval; \ + do { \ + __retval = wait_event_interruptible(wq, \ + (condition) || freezing(current)); \ + if (__retval && !freezing(current)) \ + break; \ + else if (!(condition)) \ + __retval = -ERESTARTSYS; \ + } while (try_to_freeze()); \ + __retval; \ +}) + + +#define wait_event_freezable_timeout(wq, condition, timeout) \ +({ \ + long __retval = timeout; \ + do { \ + __retval = wait_event_interruptible_timeout(wq, \ + (condition) || freezing(current), \ + __retval); \ + } while (try_to_freeze()); \ + __retval; \ +}) +#else /* !CONFIG_FREEZER */ +static inline int frozen(struct task_struct *p) { return 0; } +static inline int freezing(struct task_struct *p) { return 0; } +static inline void set_freeze_flag(struct task_struct *p) {} +static inline void clear_freeze_flag(struct task_struct *p) {} +static inline int thaw_process(struct task_struct *p) { return 1; } + +static inline void refrigerator(void) {} +static inline int freeze_processes(void) { BUG(); return 0; } +static inline void thaw_processes(void) {} + +static inline int try_to_freeze(void) { return 0; } + +static inline void freezer_do_not_count(void) {} +static inline void freezer_count(void) {} +static inline int freezer_should_skip(struct task_struct *p) { return 0; } +static inline void set_freezable(void) {} +static inline void set_freezable_with_signal(void) {} + +#define wait_event_freezable(wq, condition) \ + wait_event_interruptible(wq, condition) + +#define wait_event_freezable_timeout(wq, condition, timeout) \ + wait_event_interruptible_timeout(wq, condition, timeout) + +#endif /* !CONFIG_FREEZER */ + +#endif /* FREEZER_H_INCLUDED */ |