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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 | ||
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 | ||
88f18ba0 GS |
34 | /* |
35 | * freezing is complete, mark current process as frozen | |
36 | */ | |
37 | static inline void frozen_process(void) | |
38 | { | |
39 | if (!unlikely(current->flags & PF_NOFREEZE)) { | |
40 | current->flags |= PF_FROZEN; | |
41 | wmb(); | |
42 | } | |
0c1eecfb | 43 | clear_freeze_flag(current); |
88f18ba0 GS |
44 | } |
45 | ||
1da177e4 | 46 | /* Refrigerator is place where frozen processes are stored :-). */ |
3e1d1d28 | 47 | void refrigerator(void) |
1da177e4 LT |
48 | { |
49 | /* Hmm, should we be allowed to suspend when there are realtime | |
50 | processes around? */ | |
51 | long save; | |
33e1c288 RW |
52 | |
53 | task_lock(current); | |
54 | if (freezing(current)) { | |
88f18ba0 | 55 | frozen_process(); |
33e1c288 RW |
56 | task_unlock(current); |
57 | } else { | |
58 | task_unlock(current); | |
59 | return; | |
60 | } | |
1da177e4 | 61 | save = current->state; |
1da177e4 | 62 | pr_debug("%s entered refrigerator\n", current->comm); |
1da177e4 LT |
63 | |
64 | spin_lock_irq(¤t->sighand->siglock); | |
65 | recalc_sigpending(); /* We sent fake signal, clean it up */ | |
66 | spin_unlock_irq(¤t->sighand->siglock); | |
67 | ||
433ecb4a ON |
68 | for (;;) { |
69 | set_current_state(TASK_UNINTERRUPTIBLE); | |
70 | if (!frozen(current)) | |
71 | break; | |
1da177e4 | 72 | schedule(); |
2a23b5d1 | 73 | } |
1da177e4 | 74 | pr_debug("%s left refrigerator\n", current->comm); |
f4a3a7d6 | 75 | __set_current_state(save); |
1da177e4 LT |
76 | } |
77 | ||
13b1c3d4 | 78 | static void fake_signal_wake_up(struct task_struct *p) |
02aaeb9b RW |
79 | { |
80 | unsigned long flags; | |
81 | ||
d5d8c597 | 82 | spin_lock_irqsave(&p->sighand->siglock, flags); |
13b1c3d4 | 83 | signal_wake_up(p, 0); |
d5d8c597 RW |
84 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
85 | } | |
86 | ||
d5d8c597 RW |
87 | static int has_mm(struct task_struct *p) |
88 | { | |
89 | return (p->mm && !(p->flags & PF_BORROWED_MM)); | |
90 | } | |
91 | ||
92 | /** | |
93 | * freeze_task - send a freeze request to given task | |
94 | * @p: task to send the request to | |
95 | * @with_mm_only: if set, the request will only be sent if the task has its | |
96 | * own mm | |
97 | * Return value: 0, if @with_mm_only is set and the task has no mm of its | |
98 | * own or the task is frozen, 1, otherwise | |
99 | * | |
100 | * The freeze request is sent by seting the tasks's TIF_FREEZE flag and | |
101 | * either sending a fake signal to it or waking it up, depending on whether | |
102 | * or not it has its own mm (ie. it is a user land task). If @with_mm_only | |
103 | * is set and the task has no mm of its own (ie. it is a kernel thread), | |
104 | * its TIF_FREEZE flag should not be set. | |
105 | * | |
106 | * The task_lock() is necessary to prevent races with exit_mm() or | |
107 | * use_mm()/unuse_mm() from occuring. | |
108 | */ | |
109 | static int freeze_task(struct task_struct *p, int with_mm_only) | |
110 | { | |
111 | int ret = 1; | |
112 | ||
113 | task_lock(p); | |
114 | if (freezing(p)) { | |
115 | if (has_mm(p)) { | |
116 | if (!signal_pending(p)) | |
13b1c3d4 | 117 | fake_signal_wake_up(p); |
d5d8c597 RW |
118 | } else { |
119 | if (with_mm_only) | |
120 | ret = 0; | |
121 | else | |
122 | wake_up_state(p, TASK_INTERRUPTIBLE); | |
123 | } | |
124 | } else { | |
8a102eed | 125 | rmb(); |
d5d8c597 RW |
126 | if (frozen(p)) { |
127 | ret = 0; | |
128 | } else { | |
129 | if (has_mm(p)) { | |
130 | set_freeze_flag(p); | |
13b1c3d4 | 131 | fake_signal_wake_up(p); |
d5d8c597 RW |
132 | } else { |
133 | if (with_mm_only) { | |
134 | ret = 0; | |
135 | } else { | |
136 | set_freeze_flag(p); | |
137 | wake_up_state(p, TASK_INTERRUPTIBLE); | |
138 | } | |
139 | } | |
8a102eed | 140 | } |
02aaeb9b | 141 | } |
d5d8c597 RW |
142 | task_unlock(p); |
143 | return ret; | |
02aaeb9b RW |
144 | } |
145 | ||
a7ef7878 RW |
146 | static void cancel_freezing(struct task_struct *p) |
147 | { | |
148 | unsigned long flags; | |
149 | ||
150 | if (freezing(p)) { | |
151 | pr_debug(" clean up: %s\n", p->comm); | |
0c1eecfb | 152 | clear_freeze_flag(p); |
a7ef7878 | 153 | spin_lock_irqsave(&p->sighand->siglock, flags); |
7bb44ade | 154 | recalc_sigpending_and_wake(p); |
a7ef7878 RW |
155 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
156 | } | |
157 | } | |
158 | ||
e7cd8a72 | 159 | static int try_to_freeze_tasks(int freeze_user_space) |
1da177e4 | 160 | { |
1da177e4 | 161 | struct task_struct *g, *p; |
11b2ce2b RW |
162 | unsigned long end_time; |
163 | unsigned int todo; | |
438e2ce6 RW |
164 | struct timeval start, end; |
165 | s64 elapsed_csecs64; | |
166 | unsigned int elapsed_csecs; | |
167 | ||
168 | do_gettimeofday(&start); | |
3e1d1d28 | 169 | |
11b2ce2b | 170 | end_time = jiffies + TIMEOUT; |
1da177e4 | 171 | do { |
11b2ce2b | 172 | todo = 0; |
1da177e4 LT |
173 | read_lock(&tasklist_lock); |
174 | do_each_thread(g, p) { | |
0c1eecfb | 175 | if (frozen(p) || !freezeable(p)) |
1da177e4 | 176 | continue; |
11b2ce2b | 177 | |
d5d8c597 RW |
178 | if (!freeze_task(p, freeze_user_space)) |
179 | continue; | |
180 | ||
13b1c3d4 RM |
181 | /* |
182 | * Now that we've done set_freeze_flag, don't | |
183 | * perturb a task in TASK_STOPPED or TASK_TRACED. | |
184 | * It is "frozen enough". If the task does wake | |
185 | * up, it will immediately call try_to_freeze. | |
186 | */ | |
187 | if (!task_is_stopped_or_traced(p) && | |
188 | !freezer_should_skip(p)) | |
ba96a0c8 | 189 | todo++; |
1da177e4 LT |
190 | } while_each_thread(g, p); |
191 | read_unlock(&tasklist_lock); | |
192 | yield(); /* Yield is okay here */ | |
c2cf7d87 | 193 | if (time_after(jiffies, end_time)) |
6161b2ce | 194 | break; |
11b2ce2b | 195 | } while (todo); |
3e1d1d28 | 196 | |
438e2ce6 RW |
197 | do_gettimeofday(&end); |
198 | elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); | |
199 | do_div(elapsed_csecs64, NSEC_PER_SEC / 100); | |
200 | elapsed_csecs = elapsed_csecs64; | |
201 | ||
6161b2ce | 202 | if (todo) { |
11b2ce2b RW |
203 | /* This does not unfreeze processes that are already frozen |
204 | * (we have slightly ugly calling convention in that respect, | |
205 | * and caller must call thaw_processes() if something fails), | |
206 | * but it cleans up leftover PF_FREEZE requests. | |
207 | */ | |
14b5b7cf | 208 | printk("\n"); |
438e2ce6 | 209 | printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds " |
11b2ce2b | 210 | "(%d tasks refusing to freeze):\n", |
438e2ce6 | 211 | elapsed_csecs / 100, elapsed_csecs % 100, todo); |
328616e3 | 212 | show_state(); |
6161b2ce | 213 | read_lock(&tasklist_lock); |
02aaeb9b | 214 | do_each_thread(g, p) { |
33e1c288 | 215 | task_lock(p); |
0c1eecfb | 216 | if (freezing(p) && !freezer_should_skip(p)) |
14b5b7cf | 217 | printk(KERN_ERR " %s\n", p->comm); |
a7ef7878 | 218 | cancel_freezing(p); |
33e1c288 | 219 | task_unlock(p); |
02aaeb9b | 220 | } while_each_thread(g, p); |
6161b2ce | 221 | read_unlock(&tasklist_lock); |
438e2ce6 RW |
222 | } else { |
223 | printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100, | |
224 | elapsed_csecs % 100); | |
6161b2ce PM |
225 | } |
226 | ||
e7cd8a72 | 227 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
228 | } |
229 | ||
230 | /** | |
231 | * freeze_processes - tell processes to enter the refrigerator | |
11b2ce2b RW |
232 | */ |
233 | int freeze_processes(void) | |
234 | { | |
e7cd8a72 | 235 | int error; |
11b2ce2b | 236 | |
b842ee57 | 237 | printk("Freezing user space processes ... "); |
e7cd8a72 RW |
238 | error = try_to_freeze_tasks(FREEZER_USER_SPACE); |
239 | if (error) | |
b842ee57 RW |
240 | goto Exit; |
241 | printk("done.\n"); | |
11b2ce2b | 242 | |
b842ee57 | 243 | printk("Freezing remaining freezable tasks ... "); |
e7cd8a72 RW |
244 | error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); |
245 | if (error) | |
b842ee57 RW |
246 | goto Exit; |
247 | printk("done."); | |
248 | Exit: | |
1da177e4 | 249 | BUG_ON(in_atomic()); |
b842ee57 RW |
250 | printk("\n"); |
251 | return error; | |
1da177e4 LT |
252 | } |
253 | ||
a9b6f562 | 254 | static void thaw_tasks(int thaw_user_space) |
1da177e4 LT |
255 | { |
256 | struct task_struct *g, *p; | |
257 | ||
1da177e4 | 258 | read_lock(&tasklist_lock); |
a9b6f562 RW |
259 | do_each_thread(g, p) { |
260 | if (!freezeable(p)) | |
261 | continue; | |
ff39593a | 262 | |
0c1eecfb | 263 | if (!p->mm == thaw_user_space) |
a9b6f562 | 264 | continue; |
1da177e4 | 265 | |
ba96a0c8 | 266 | thaw_process(p); |
a9b6f562 | 267 | } while_each_thread(g, p); |
1da177e4 | 268 | read_unlock(&tasklist_lock); |
a9b6f562 RW |
269 | } |
270 | ||
271 | void thaw_processes(void) | |
272 | { | |
273 | printk("Restarting tasks ... "); | |
274 | thaw_tasks(FREEZER_KERNEL_THREADS); | |
275 | thaw_tasks(FREEZER_USER_SPACE); | |
1da177e4 | 276 | schedule(); |
14b5b7cf | 277 | printk("done.\n"); |
1da177e4 LT |
278 | } |
279 | ||
280 | EXPORT_SYMBOL(refrigerator); |