Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 */
13static 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 */
21static 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 */
29static 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 */
37static inline void clear_freeze_flag(struct task_struct *p)
38{
39 clear_tsk_thread_flag(p, TIF_FREEZE);
40}
41
42static 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() */
48extern int thaw_process(struct task_struct *p);
49
50extern void refrigerator(void);
51extern int freeze_processes(void);
52extern int freeze_kernel_threads(void);
53extern void thaw_processes(void);
54
55static inline int try_to_freeze(void)
56{
57 if (freezing(current)) {
58 refrigerator();
59 return 1;
60 } else
61 return 0;
62}
63
64extern bool freeze_task(struct task_struct *p, bool sig_only);
65extern void cancel_freezing(struct task_struct *p);
66
67#ifdef CONFIG_CGROUP_FREEZER
68extern int cgroup_freezing_or_frozen(struct task_struct *task);
69#else /* !CONFIG_CGROUP_FREEZER */
70static 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 */
94static 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 */
104static 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 */
115static 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 */
123static 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 */
132static 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(),
139 * wait_event_killable() and wait_event_interruptible_timeout(), originally
140 * defined in <linux/wait.h>
141 */
142
143#define wait_event_freezekillable(wq, condition) \
144({ \
145 int __retval; \
146 freezer_do_not_count(); \
147 __retval = wait_event_killable(wq, (condition)); \
148 freezer_count(); \
149 __retval; \
150})
151
152#define wait_event_freezable(wq, condition) \
153({ \
154 int __retval; \
155 do { \
156 __retval = wait_event_interruptible(wq, \
157 (condition) || freezing(current)); \
158 if (__retval && !freezing(current)) \
159 break; \
160 else if (!(condition)) \
161 __retval = -ERESTARTSYS; \
162 } while (try_to_freeze()); \
163 __retval; \
164})
165
166
167#define wait_event_freezable_timeout(wq, condition, timeout) \
168({ \
169 long __retval = timeout; \
170 do { \
171 __retval = wait_event_interruptible_timeout(wq, \
172 (condition) || freezing(current), \
173 __retval); \
174 } while (try_to_freeze()); \
175 __retval; \
176})
177#else /* !CONFIG_FREEZER */
178static inline int frozen(struct task_struct *p) { return 0; }
179static inline int freezing(struct task_struct *p) { return 0; }
180static inline void set_freeze_flag(struct task_struct *p) {}
181static inline void clear_freeze_flag(struct task_struct *p) {}
182static inline int thaw_process(struct task_struct *p) { return 1; }
183
184static inline void refrigerator(void) {}
185static inline int freeze_processes(void) { return -ENOSYS; }
186static inline int freeze_kernel_threads(void) { return -ENOSYS; }
187static inline void thaw_processes(void) {}
188
189static inline int try_to_freeze(void) { return 0; }
190
191static inline void freezer_do_not_count(void) {}
192static inline void freezer_count(void) {}
193static inline int freezer_should_skip(struct task_struct *p) { return 0; }
194static inline void set_freezable(void) {}
195static inline void set_freezable_with_signal(void) {}
196
197#define wait_event_freezable(wq, condition) \
198 wait_event_interruptible(wq, condition)
199
200#define wait_event_freezable_timeout(wq, condition, timeout) \
201 wait_event_interruptible_timeout(wq, condition, timeout)
202
203#define wait_event_freezekillable(wq, condition) \
204 wait_event_killable(wq, condition)
205
206#endif /* !CONFIG_FREEZER */
207
208#endif /* FREEZER_H_INCLUDED */