include/linux/freezer.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Freezer declarations */
   3
   4 #ifndef FREEZER_H_INCLUDED
   5 #define FREEZER_H_INCLUDED
   6
   7 #include <linux/debug_locks.h>
   8 #include <linux/sched.h>
   9 #include <linux/wait.h>
  10 #include <linux/atomic.h>
  11 #include <linux/jump_label.h>
  12
  13 #ifdef CONFIG_FREEZER
  14 DECLARE_STATIC_KEY_FALSE(freezer_active);
  15
  16 extern bool pm_freezing;                /* PM freezing in effect */
  17 extern bool pm_nosig_freezing;          /* PM nosig freezing in effect */
  18
  19 /*
  20  * Timeout for stopping processes
  21  */
  22 extern unsigned int freeze_timeout_msecs;
  23
  24 /*
  25  * Check if a process has been frozen
  26  */
  27 extern bool frozen(struct task_struct *p);
  28
  29 extern bool freezing_slow_path(struct task_struct *p);
  30
  31 /*
  32  * Check if there is a request to freeze a process
  33  */
  34 static inline bool freezing(struct task_struct *p)
  35 {
  36         if (static_branch_unlikely(&freezer_active))
  37                 return freezing_slow_path(p);
  38
  39         return false;
  40 }
  41
  42 /* Takes and releases task alloc lock using task_lock() */
  43 extern void __thaw_task(struct task_struct *t);
  44
  45 extern bool __refrigerator(bool check_kthr_stop);
  46 extern int freeze_processes(void);
  47 extern int freeze_kernel_threads(void);
  48 extern void thaw_processes(void);
  49 extern void thaw_kernel_threads(void);
  50
  51 static inline bool try_to_freeze(void)
  52 {
  53         might_sleep();
  54         if (likely(!freezing(current)))
  55                 return false;
  56         if (!(current->flags & PF_NOFREEZE))
  57                 debug_check_no_locks_held();
  58         return __refrigerator(false);
  59 }
  60
  61 extern bool freeze_task(struct task_struct *p);
  62 extern bool set_freezable(void);
  63
  64 #ifdef CONFIG_CGROUP_FREEZER
  65 extern bool cgroup_freezing(struct task_struct *task);
  66 #else /* !CONFIG_CGROUP_FREEZER */
  67 static inline bool cgroup_freezing(struct task_struct *task)
  68 {
  69         return false;
  70 }
  71 #endif /* !CONFIG_CGROUP_FREEZER */
  72
  73 #else /* !CONFIG_FREEZER */
  74 static inline bool frozen(struct task_struct *p) { return false; }
  75 static inline bool freezing(struct task_struct *p) { return false; }
  76 static inline void __thaw_task(struct task_struct *t) {}
  77
  78 static inline bool __refrigerator(bool check_kthr_stop) { return false; }
  79 static inline int freeze_processes(void) { return -ENOSYS; }
  80 static inline int freeze_kernel_threads(void) { return -ENOSYS; }
  81 static inline void thaw_processes(void) {}
  82 static inline void thaw_kernel_threads(void) {}
  83
  84 static inline bool try_to_freeze(void) { return false; }
  85
  86 static inline void set_freezable(void) {}
  87
  88 #endif /* !CONFIG_FREEZER */
  89
  90 #endif  /* FREEZER_H_INCLUDED */