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7#include <linux/interrupt.h>
8#include <linux/suspend.h>
9#include <linux/export.h>
10#include <linux/syscalls.h>
11#include <linux/freezer.h>
12#include <linux/kthread.h>
13
14
15atomic_t system_freezing_cnt = ATOMIC_INIT(0);
16EXPORT_SYMBOL(system_freezing_cnt);
17
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19bool pm_freezing;
20bool pm_nosig_freezing;
21
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23static DEFINE_SPINLOCK(freezer_lock);
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34bool freezing_slow_path(struct task_struct *p)
35{
36 if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
37 return false;
38
39 if (pm_nosig_freezing || cgroup_freezing(p))
40 return true;
41
42 if (pm_freezing && !(p->flags & PF_KTHREAD))
43 return true;
44
45 return false;
46}
47EXPORT_SYMBOL(freezing_slow_path);
48
49
50bool __refrigerator(bool check_kthr_stop)
51{
52
53
54 bool was_frozen = false;
55 long save = current->state;
56
57 pr_debug("%s entered refrigerator\n", current->comm);
58
59 for (;;) {
60 set_current_state(TASK_UNINTERRUPTIBLE);
61
62 spin_lock_irq(&freezer_lock);
63 current->flags |= PF_FROZEN;
64 if (!freezing(current) ||
65 (check_kthr_stop && kthread_should_stop()))
66 current->flags &= ~PF_FROZEN;
67 spin_unlock_irq(&freezer_lock);
68
69 if (!(current->flags & PF_FROZEN))
70 break;
71 was_frozen = true;
72 schedule();
73 }
74
75 pr_debug("%s left refrigerator\n", current->comm);
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82 set_current_state(save);
83
84 return was_frozen;
85}
86EXPORT_SYMBOL(__refrigerator);
87
88static void fake_signal_wake_up(struct task_struct *p)
89{
90 unsigned long flags;
91
92 if (lock_task_sighand(p, &flags)) {
93 signal_wake_up(p, 0);
94 unlock_task_sighand(p, &flags);
95 }
96}
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108
109bool freeze_task(struct task_struct *p)
110{
111 unsigned long flags;
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121
122 if (freezer_should_skip(p))
123 return false;
124
125 spin_lock_irqsave(&freezer_lock, flags);
126 if (!freezing(p) || frozen(p)) {
127 spin_unlock_irqrestore(&freezer_lock, flags);
128 return false;
129 }
130
131 if (!(p->flags & PF_KTHREAD))
132 fake_signal_wake_up(p);
133 else
134 wake_up_state(p, TASK_INTERRUPTIBLE);
135
136 spin_unlock_irqrestore(&freezer_lock, flags);
137 return true;
138}
139
140void __thaw_task(struct task_struct *p)
141{
142 unsigned long flags;
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150 spin_lock_irqsave(&freezer_lock, flags);
151 if (frozen(p))
152 wake_up_process(p);
153 spin_unlock_irqrestore(&freezer_lock, flags);
154}
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161bool set_freezable(void)
162{
163 might_sleep();
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169
170 spin_lock_irq(&freezer_lock);
171 current->flags &= ~PF_NOFREEZE;
172 spin_unlock_irq(&freezer_lock);
173
174 return try_to_freeze();
175}
176EXPORT_SYMBOL(set_freezable);
177