Commit | Line | Data |
---|---|---|
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 | ||
1da177e4 LT |
11 | #include <linux/interrupt.h> |
12 | #include <linux/suspend.h> | |
13 | #include <linux/module.h> | |
02aaeb9b | 14 | #include <linux/syscalls.h> |
7dfb7103 | 15 | #include <linux/freezer.h> |
1da177e4 LT |
16 | |
17 | /* | |
18 | * Timeout for stopping processes | |
19 | */ | |
02aaeb9b | 20 | #define TIMEOUT (20 * HZ) |
1da177e4 | 21 | |
a9b6f562 RW |
22 | #define FREEZER_KERNEL_THREADS 0 |
23 | #define FREEZER_USER_SPACE 1 | |
1da177e4 LT |
24 | |
25 | static inline int freezeable(struct task_struct * p) | |
26 | { | |
1065d130 | 27 | if ((p == current) || |
1da177e4 | 28 | (p->flags & PF_NOFREEZE) || |
1065d130 | 29 | (p->exit_state != 0)) |
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; | |
33e1c288 RW |
40 | |
41 | task_lock(current); | |
42 | if (freezing(current)) { | |
43 | frozen_process(current); | |
44 | task_unlock(current); | |
45 | } else { | |
46 | task_unlock(current); | |
47 | return; | |
48 | } | |
1da177e4 | 49 | save = current->state; |
1da177e4 | 50 | pr_debug("%s entered refrigerator\n", current->comm); |
1da177e4 LT |
51 | |
52 | spin_lock_irq(¤t->sighand->siglock); | |
53 | recalc_sigpending(); /* We sent fake signal, clean it up */ | |
54 | spin_unlock_irq(¤t->sighand->siglock); | |
55 | ||
433ecb4a ON |
56 | for (;;) { |
57 | set_current_state(TASK_UNINTERRUPTIBLE); | |
58 | if (!frozen(current)) | |
59 | break; | |
1da177e4 | 60 | schedule(); |
2a23b5d1 | 61 | } |
1da177e4 LT |
62 | pr_debug("%s left refrigerator\n", current->comm); |
63 | current->state = save; | |
64 | } | |
65 | ||
02aaeb9b RW |
66 | static inline void freeze_process(struct task_struct *p) |
67 | { | |
68 | unsigned long flags; | |
69 | ||
70 | if (!freezing(p)) { | |
8a102eed RW |
71 | rmb(); |
72 | if (!frozen(p)) { | |
73 | if (p->state == TASK_STOPPED) | |
74 | force_sig_specific(SIGSTOP, p); | |
3df494a3 | 75 | |
8a102eed RW |
76 | freeze(p); |
77 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
78 | signal_wake_up(p, p->state == TASK_STOPPED); | |
79 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
80 | } | |
02aaeb9b RW |
81 | } |
82 | } | |
83 | ||
a7ef7878 RW |
84 | static void cancel_freezing(struct task_struct *p) |
85 | { | |
86 | unsigned long flags; | |
87 | ||
88 | if (freezing(p)) { | |
89 | pr_debug(" clean up: %s\n", p->comm); | |
90 | do_not_freeze(p); | |
91 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
92 | recalc_sigpending_tsk(p); | |
93 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
94 | } | |
95 | } | |
96 | ||
a9b6f562 RW |
97 | static inline int is_user_space(struct task_struct *p) |
98 | { | |
99 | return p->mm && !(p->flags & PF_BORROWED_MM); | |
100 | } | |
101 | ||
11b2ce2b | 102 | static unsigned int try_to_freeze_tasks(int freeze_user_space) |
1da177e4 | 103 | { |
1da177e4 | 104 | struct task_struct *g, *p; |
11b2ce2b RW |
105 | unsigned long end_time; |
106 | unsigned int todo; | |
3e1d1d28 | 107 | |
11b2ce2b | 108 | end_time = jiffies + TIMEOUT; |
1da177e4 | 109 | do { |
11b2ce2b | 110 | todo = 0; |
1da177e4 LT |
111 | read_lock(&tasklist_lock); |
112 | do_each_thread(g, p) { | |
1da177e4 LT |
113 | if (!freezeable(p)) |
114 | continue; | |
11b2ce2b | 115 | |
1322ad41 | 116 | if (frozen(p)) |
1da177e4 | 117 | continue; |
11b2ce2b | 118 | |
3df494a3 | 119 | if (p->state == TASK_TRACED && frozen(p->parent)) { |
a7ef7878 RW |
120 | cancel_freezing(p); |
121 | continue; | |
122 | } | |
49b12d4f | 123 | if (freeze_user_space && !is_user_space(p)) |
ba96a0c8 RW |
124 | continue; |
125 | ||
126 | freeze_process(p); | |
127 | if (!freezer_should_skip(p)) | |
128 | todo++; | |
1da177e4 LT |
129 | } while_each_thread(g, p); |
130 | read_unlock(&tasklist_lock); | |
131 | yield(); /* Yield is okay here */ | |
11b2ce2b | 132 | if (todo && time_after(jiffies, end_time)) |
6161b2ce | 133 | break; |
11b2ce2b | 134 | } while (todo); |
3e1d1d28 | 135 | |
6161b2ce | 136 | if (todo) { |
11b2ce2b RW |
137 | /* This does not unfreeze processes that are already frozen |
138 | * (we have slightly ugly calling convention in that respect, | |
139 | * and caller must call thaw_processes() if something fails), | |
140 | * but it cleans up leftover PF_FREEZE requests. | |
141 | */ | |
14b5b7cf | 142 | printk("\n"); |
11b2ce2b RW |
143 | printk(KERN_ERR "Stopping %s timed out after %d seconds " |
144 | "(%d tasks refusing to freeze):\n", | |
145 | freeze_user_space ? "user space processes" : | |
146 | "kernel threads", | |
147 | TIMEOUT / HZ, todo); | |
6161b2ce | 148 | read_lock(&tasklist_lock); |
02aaeb9b | 149 | do_each_thread(g, p) { |
49b12d4f | 150 | if (freeze_user_space && !is_user_space(p)) |
11b2ce2b RW |
151 | continue; |
152 | ||
33e1c288 | 153 | task_lock(p); |
ba96a0c8 RW |
154 | if (freezeable(p) && !frozen(p) && |
155 | !freezer_should_skip(p)) | |
14b5b7cf | 156 | printk(KERN_ERR " %s\n", p->comm); |
11b2ce2b | 157 | |
a7ef7878 | 158 | cancel_freezing(p); |
33e1c288 | 159 | task_unlock(p); |
02aaeb9b | 160 | } while_each_thread(g, p); |
6161b2ce | 161 | read_unlock(&tasklist_lock); |
6161b2ce PM |
162 | } |
163 | ||
11b2ce2b RW |
164 | return todo; |
165 | } | |
166 | ||
167 | /** | |
168 | * freeze_processes - tell processes to enter the refrigerator | |
169 | * | |
170 | * Returns 0 on success, or the number of processes that didn't freeze, | |
171 | * although they were told to. | |
172 | */ | |
173 | int freeze_processes(void) | |
174 | { | |
175 | unsigned int nr_unfrozen; | |
176 | ||
177 | printk("Stopping tasks ... "); | |
178 | nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE); | |
179 | if (nr_unfrozen) | |
180 | return nr_unfrozen; | |
181 | ||
182 | sys_sync(); | |
183 | nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); | |
184 | if (nr_unfrozen) | |
185 | return nr_unfrozen; | |
186 | ||
14b5b7cf | 187 | printk("done.\n"); |
1da177e4 LT |
188 | BUG_ON(in_atomic()); |
189 | return 0; | |
190 | } | |
191 | ||
a9b6f562 | 192 | static void thaw_tasks(int thaw_user_space) |
1da177e4 LT |
193 | { |
194 | struct task_struct *g, *p; | |
195 | ||
1da177e4 | 196 | read_lock(&tasklist_lock); |
a9b6f562 RW |
197 | do_each_thread(g, p) { |
198 | if (!freezeable(p)) | |
199 | continue; | |
ff39593a | 200 | |
a9b6f562 RW |
201 | if (is_user_space(p) == !thaw_user_space) |
202 | continue; | |
1da177e4 | 203 | |
ba96a0c8 | 204 | thaw_process(p); |
a9b6f562 | 205 | } while_each_thread(g, p); |
1da177e4 | 206 | read_unlock(&tasklist_lock); |
a9b6f562 RW |
207 | } |
208 | ||
209 | void thaw_processes(void) | |
210 | { | |
211 | printk("Restarting tasks ... "); | |
212 | thaw_tasks(FREEZER_KERNEL_THREADS); | |
213 | thaw_tasks(FREEZER_USER_SPACE); | |
1da177e4 | 214 | schedule(); |
14b5b7cf | 215 | printk("done.\n"); |
1da177e4 LT |
216 | } |
217 | ||
218 | EXPORT_SYMBOL(refrigerator); |