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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * drivers/power/process.c - Functions for starting/stopping processes on | |
3 | * suspend transitions. | |
4 | * | |
5 | * Originally from swsusp. | |
6 | */ | |
7 | ||
8 | ||
9 | #undef DEBUG | |
10 | ||
11 | #include <linux/smp_lock.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/suspend.h> | |
14 | #include <linux/module.h> | |
02aaeb9b | 15 | #include <linux/syscalls.h> |
1da177e4 LT |
16 | |
17 | /* | |
18 | * Timeout for stopping processes | |
19 | */ | |
02aaeb9b | 20 | #define TIMEOUT (20 * HZ) |
1da177e4 LT |
21 | |
22 | ||
23 | static inline int freezeable(struct task_struct * p) | |
24 | { | |
25 | if ((p == current) || | |
26 | (p->flags & PF_NOFREEZE) || | |
27 | (p->exit_state == EXIT_ZOMBIE) || | |
28 | (p->exit_state == EXIT_DEAD) || | |
85b6bce3 | 29 | (p->state == TASK_STOPPED)) |
1da177e4 LT |
30 | return 0; |
31 | return 1; | |
32 | } | |
33 | ||
34 | /* Refrigerator is place where frozen processes are stored :-). */ | |
3e1d1d28 | 35 | void refrigerator(void) |
1da177e4 LT |
36 | { |
37 | /* Hmm, should we be allowed to suspend when there are realtime | |
38 | processes around? */ | |
39 | long save; | |
40 | save = current->state; | |
1da177e4 LT |
41 | pr_debug("%s entered refrigerator\n", current->comm); |
42 | printk("="); | |
1da177e4 | 43 | |
3e1d1d28 | 44 | frozen_process(current); |
1da177e4 LT |
45 | spin_lock_irq(¤t->sighand->siglock); |
46 | recalc_sigpending(); /* We sent fake signal, clean it up */ | |
47 | spin_unlock_irq(¤t->sighand->siglock); | |
48 | ||
2a23b5d1 PM |
49 | while (frozen(current)) { |
50 | current->state = TASK_UNINTERRUPTIBLE; | |
1da177e4 | 51 | schedule(); |
2a23b5d1 | 52 | } |
1da177e4 LT |
53 | pr_debug("%s left refrigerator\n", current->comm); |
54 | current->state = save; | |
55 | } | |
56 | ||
02aaeb9b RW |
57 | static inline void freeze_process(struct task_struct *p) |
58 | { | |
59 | unsigned long flags; | |
60 | ||
61 | if (!freezing(p)) { | |
62 | freeze(p); | |
63 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
64 | signal_wake_up(p, 0); | |
65 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
66 | } | |
67 | } | |
68 | ||
a7ef7878 RW |
69 | static void cancel_freezing(struct task_struct *p) |
70 | { | |
71 | unsigned long flags; | |
72 | ||
73 | if (freezing(p)) { | |
74 | pr_debug(" clean up: %s\n", p->comm); | |
75 | do_not_freeze(p); | |
76 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
77 | recalc_sigpending_tsk(p); | |
78 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
79 | } | |
80 | } | |
81 | ||
1da177e4 LT |
82 | /* 0 = success, else # of processes that we failed to stop */ |
83 | int freeze_processes(void) | |
84 | { | |
02aaeb9b | 85 | int todo, nr_user, user_frozen; |
3e1d1d28 | 86 | unsigned long start_time; |
1da177e4 | 87 | struct task_struct *g, *p; |
3e1d1d28 | 88 | |
1da177e4 LT |
89 | printk( "Stopping tasks: " ); |
90 | start_time = jiffies; | |
02aaeb9b | 91 | user_frozen = 0; |
1da177e4 | 92 | do { |
02aaeb9b | 93 | nr_user = todo = 0; |
1da177e4 LT |
94 | read_lock(&tasklist_lock); |
95 | do_each_thread(g, p) { | |
1da177e4 LT |
96 | if (!freezeable(p)) |
97 | continue; | |
1322ad41 | 98 | if (frozen(p)) |
1da177e4 | 99 | continue; |
a7ef7878 RW |
100 | if (p->state == TASK_TRACED && frozen(p->parent)) { |
101 | cancel_freezing(p); | |
102 | continue; | |
103 | } | |
02aaeb9b RW |
104 | if (p->mm && !(p->flags & PF_BORROWED_MM)) { |
105 | /* The task is a user-space one. | |
106 | * Freeze it unless there's a vfork completion | |
107 | * pending | |
108 | */ | |
109 | if (!p->vfork_done) | |
110 | freeze_process(p); | |
111 | nr_user++; | |
112 | } else { | |
113 | /* Freeze only if the user space is frozen */ | |
114 | if (user_frozen) | |
115 | freeze_process(p); | |
116 | todo++; | |
117 | } | |
1da177e4 LT |
118 | } while_each_thread(g, p); |
119 | read_unlock(&tasklist_lock); | |
02aaeb9b RW |
120 | todo += nr_user; |
121 | if (!user_frozen && !nr_user) { | |
122 | sys_sync(); | |
123 | start_time = jiffies; | |
124 | } | |
125 | user_frozen = !nr_user; | |
1da177e4 | 126 | yield(); /* Yield is okay here */ |
02aaeb9b | 127 | if (todo && time_after(jiffies, start_time + TIMEOUT)) |
6161b2ce | 128 | break; |
1da177e4 | 129 | } while(todo); |
3e1d1d28 | 130 | |
6161b2ce PM |
131 | /* This does not unfreeze processes that are already frozen |
132 | * (we have slightly ugly calling convention in that respect, | |
133 | * and caller must call thaw_processes() if something fails), | |
134 | * but it cleans up leftover PF_FREEZE requests. | |
135 | */ | |
136 | if (todo) { | |
02aaeb9b RW |
137 | printk( "\n" ); |
138 | printk(KERN_ERR " stopping tasks timed out " | |
139 | "after %d seconds (%d tasks remaining):\n", | |
140 | TIMEOUT / HZ, todo); | |
6161b2ce | 141 | read_lock(&tasklist_lock); |
02aaeb9b RW |
142 | do_each_thread(g, p) { |
143 | if (freezeable(p) && !frozen(p)) | |
144 | printk(KERN_ERR " %s\n", p->comm); | |
a7ef7878 | 145 | cancel_freezing(p); |
02aaeb9b | 146 | } while_each_thread(g, p); |
6161b2ce PM |
147 | read_unlock(&tasklist_lock); |
148 | return todo; | |
149 | } | |
150 | ||
1da177e4 LT |
151 | printk( "|\n" ); |
152 | BUG_ON(in_atomic()); | |
153 | return 0; | |
154 | } | |
155 | ||
156 | void thaw_processes(void) | |
157 | { | |
158 | struct task_struct *g, *p; | |
159 | ||
160 | printk( "Restarting tasks..." ); | |
161 | read_lock(&tasklist_lock); | |
162 | do_each_thread(g, p) { | |
163 | if (!freezeable(p)) | |
164 | continue; | |
3e1d1d28 | 165 | if (!thaw_process(p)) |
1da177e4 LT |
166 | printk(KERN_INFO " Strange, %s not stopped\n", p->comm ); |
167 | } while_each_thread(g, p); | |
168 | ||
169 | read_unlock(&tasklist_lock); | |
170 | schedule(); | |
171 | printk( " done\n" ); | |
172 | } | |
173 | ||
174 | EXPORT_SYMBOL(refrigerator); |