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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> |
7dfb7103 | 16 | #include <linux/freezer.h> |
1da177e4 LT |
17 | |
18 | /* | |
19 | * Timeout for stopping processes | |
20 | */ | |
02aaeb9b | 21 | #define TIMEOUT (20 * HZ) |
1da177e4 | 22 | |
a9b6f562 RW |
23 | #define FREEZER_KERNEL_THREADS 0 |
24 | #define FREEZER_USER_SPACE 1 | |
1da177e4 LT |
25 | |
26 | static inline int freezeable(struct task_struct * p) | |
27 | { | |
28 | if ((p == current) || | |
29 | (p->flags & PF_NOFREEZE) || | |
30 | (p->exit_state == EXIT_ZOMBIE) || | |
31 | (p->exit_state == EXIT_DEAD) || | |
85b6bce3 | 32 | (p->state == TASK_STOPPED)) |
1da177e4 LT |
33 | return 0; |
34 | return 1; | |
35 | } | |
36 | ||
37 | /* Refrigerator is place where frozen processes are stored :-). */ | |
3e1d1d28 | 38 | void refrigerator(void) |
1da177e4 LT |
39 | { |
40 | /* Hmm, should we be allowed to suspend when there are realtime | |
41 | processes around? */ | |
42 | long save; | |
43 | save = current->state; | |
1da177e4 | 44 | pr_debug("%s entered refrigerator\n", current->comm); |
1da177e4 | 45 | |
3e1d1d28 | 46 | frozen_process(current); |
1da177e4 LT |
47 | spin_lock_irq(¤t->sighand->siglock); |
48 | recalc_sigpending(); /* We sent fake signal, clean it up */ | |
49 | spin_unlock_irq(¤t->sighand->siglock); | |
50 | ||
2a23b5d1 PM |
51 | while (frozen(current)) { |
52 | current->state = TASK_UNINTERRUPTIBLE; | |
1da177e4 | 53 | schedule(); |
2a23b5d1 | 54 | } |
1da177e4 LT |
55 | pr_debug("%s left refrigerator\n", current->comm); |
56 | current->state = save; | |
57 | } | |
58 | ||
02aaeb9b RW |
59 | static inline void freeze_process(struct task_struct *p) |
60 | { | |
61 | unsigned long flags; | |
62 | ||
63 | if (!freezing(p)) { | |
64 | freeze(p); | |
65 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
66 | signal_wake_up(p, 0); | |
67 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
68 | } | |
69 | } | |
70 | ||
a7ef7878 RW |
71 | static void cancel_freezing(struct task_struct *p) |
72 | { | |
73 | unsigned long flags; | |
74 | ||
75 | if (freezing(p)) { | |
76 | pr_debug(" clean up: %s\n", p->comm); | |
77 | do_not_freeze(p); | |
78 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
79 | recalc_sigpending_tsk(p); | |
80 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
81 | } | |
82 | } | |
83 | ||
a9b6f562 RW |
84 | static inline int is_user_space(struct task_struct *p) |
85 | { | |
86 | return p->mm && !(p->flags & PF_BORROWED_MM); | |
87 | } | |
88 | ||
1da177e4 LT |
89 | /* 0 = success, else # of processes that we failed to stop */ |
90 | int freeze_processes(void) | |
91 | { | |
02aaeb9b | 92 | int todo, nr_user, user_frozen; |
3e1d1d28 | 93 | unsigned long start_time; |
1da177e4 | 94 | struct task_struct *g, *p; |
3e1d1d28 | 95 | |
14b5b7cf | 96 | printk("Stopping tasks... "); |
1da177e4 | 97 | start_time = jiffies; |
02aaeb9b | 98 | user_frozen = 0; |
1da177e4 | 99 | do { |
02aaeb9b | 100 | nr_user = todo = 0; |
1da177e4 LT |
101 | read_lock(&tasklist_lock); |
102 | do_each_thread(g, p) { | |
1da177e4 LT |
103 | if (!freezeable(p)) |
104 | continue; | |
1322ad41 | 105 | if (frozen(p)) |
1da177e4 | 106 | continue; |
3eb1b3a4 RW |
107 | if (p->state == TASK_TRACED && |
108 | (frozen(p->parent) || | |
109 | p->parent->state == TASK_STOPPED)) { | |
a7ef7878 RW |
110 | cancel_freezing(p); |
111 | continue; | |
112 | } | |
a9b6f562 RW |
113 | if (is_user_space(p)) { |
114 | /* Freeze the task unless there is a vfork | |
115 | * completion pending | |
02aaeb9b RW |
116 | */ |
117 | if (!p->vfork_done) | |
118 | freeze_process(p); | |
119 | nr_user++; | |
120 | } else { | |
121 | /* Freeze only if the user space is frozen */ | |
122 | if (user_frozen) | |
123 | freeze_process(p); | |
124 | todo++; | |
125 | } | |
1da177e4 LT |
126 | } while_each_thread(g, p); |
127 | read_unlock(&tasklist_lock); | |
02aaeb9b RW |
128 | todo += nr_user; |
129 | if (!user_frozen && !nr_user) { | |
130 | sys_sync(); | |
131 | start_time = jiffies; | |
132 | } | |
133 | user_frozen = !nr_user; | |
1da177e4 | 134 | yield(); /* Yield is okay here */ |
02aaeb9b | 135 | if (todo && time_after(jiffies, start_time + TIMEOUT)) |
6161b2ce | 136 | break; |
1da177e4 | 137 | } while(todo); |
3e1d1d28 | 138 | |
6161b2ce PM |
139 | /* This does not unfreeze processes that are already frozen |
140 | * (we have slightly ugly calling convention in that respect, | |
141 | * and caller must call thaw_processes() if something fails), | |
142 | * but it cleans up leftover PF_FREEZE requests. | |
143 | */ | |
144 | if (todo) { | |
14b5b7cf NC |
145 | printk("\n"); |
146 | printk(KERN_ERR "Stopping tasks timed out " | |
02aaeb9b RW |
147 | "after %d seconds (%d tasks remaining):\n", |
148 | TIMEOUT / HZ, todo); | |
6161b2ce | 149 | read_lock(&tasklist_lock); |
02aaeb9b RW |
150 | do_each_thread(g, p) { |
151 | if (freezeable(p) && !frozen(p)) | |
14b5b7cf | 152 | printk(KERN_ERR " %s\n", p->comm); |
a7ef7878 | 153 | cancel_freezing(p); |
02aaeb9b | 154 | } while_each_thread(g, p); |
6161b2ce PM |
155 | read_unlock(&tasklist_lock); |
156 | return todo; | |
157 | } | |
158 | ||
14b5b7cf | 159 | printk("done.\n"); |
1da177e4 LT |
160 | BUG_ON(in_atomic()); |
161 | return 0; | |
162 | } | |
163 | ||
a9b6f562 | 164 | static void thaw_tasks(int thaw_user_space) |
1da177e4 LT |
165 | { |
166 | struct task_struct *g, *p; | |
167 | ||
1da177e4 | 168 | read_lock(&tasklist_lock); |
a9b6f562 RW |
169 | do_each_thread(g, p) { |
170 | if (!freezeable(p)) | |
171 | continue; | |
ff39593a | 172 | |
a9b6f562 RW |
173 | if (is_user_space(p) == !thaw_user_space) |
174 | continue; | |
1da177e4 | 175 | |
a9b6f562 RW |
176 | if (!thaw_process(p)) |
177 | printk(KERN_WARNING " Strange, %s not stopped\n", | |
178 | p->comm ); | |
179 | } while_each_thread(g, p); | |
1da177e4 | 180 | read_unlock(&tasklist_lock); |
a9b6f562 RW |
181 | } |
182 | ||
183 | void thaw_processes(void) | |
184 | { | |
185 | printk("Restarting tasks ... "); | |
186 | thaw_tasks(FREEZER_KERNEL_THREADS); | |
187 | thaw_tasks(FREEZER_USER_SPACE); | |
1da177e4 | 188 | schedule(); |
14b5b7cf | 189 | printk("done.\n"); |
1da177e4 LT |
190 | } |
191 | ||
192 | EXPORT_SYMBOL(refrigerator); |