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 | ||
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 | ||
d5d8c597 | 78 | static void fake_signal_wake_up(struct task_struct *p, int resume) |
02aaeb9b RW |
79 | { |
80 | unsigned long flags; | |
81 | ||
d5d8c597 RW |
82 | spin_lock_irqsave(&p->sighand->siglock, flags); |
83 | signal_wake_up(p, resume); | |
84 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
85 | } | |
86 | ||
87 | static void send_fake_signal(struct task_struct *p) | |
88 | { | |
89 | if (p->state == TASK_STOPPED) | |
90 | force_sig_specific(SIGSTOP, p); | |
91 | fake_signal_wake_up(p, p->state == TASK_STOPPED); | |
92 | } | |
93 | ||
94 | static int has_mm(struct task_struct *p) | |
95 | { | |
96 | return (p->mm && !(p->flags & PF_BORROWED_MM)); | |
97 | } | |
98 | ||
99 | /** | |
100 | * freeze_task - send a freeze request to given task | |
101 | * @p: task to send the request to | |
102 | * @with_mm_only: if set, the request will only be sent if the task has its | |
103 | * own mm | |
104 | * Return value: 0, if @with_mm_only is set and the task has no mm of its | |
105 | * own or the task is frozen, 1, otherwise | |
106 | * | |
107 | * The freeze request is sent by seting the tasks's TIF_FREEZE flag and | |
108 | * either sending a fake signal to it or waking it up, depending on whether | |
109 | * or not it has its own mm (ie. it is a user land task). If @with_mm_only | |
110 | * is set and the task has no mm of its own (ie. it is a kernel thread), | |
111 | * its TIF_FREEZE flag should not be set. | |
112 | * | |
113 | * The task_lock() is necessary to prevent races with exit_mm() or | |
114 | * use_mm()/unuse_mm() from occuring. | |
115 | */ | |
116 | static int freeze_task(struct task_struct *p, int with_mm_only) | |
117 | { | |
118 | int ret = 1; | |
119 | ||
120 | task_lock(p); | |
121 | if (freezing(p)) { | |
122 | if (has_mm(p)) { | |
123 | if (!signal_pending(p)) | |
124 | fake_signal_wake_up(p, 0); | |
125 | } else { | |
126 | if (with_mm_only) | |
127 | ret = 0; | |
128 | else | |
129 | wake_up_state(p, TASK_INTERRUPTIBLE); | |
130 | } | |
131 | } else { | |
8a102eed | 132 | rmb(); |
d5d8c597 RW |
133 | if (frozen(p)) { |
134 | ret = 0; | |
135 | } else { | |
136 | if (has_mm(p)) { | |
137 | set_freeze_flag(p); | |
138 | send_fake_signal(p); | |
139 | } else { | |
140 | if (with_mm_only) { | |
141 | ret = 0; | |
142 | } else { | |
143 | set_freeze_flag(p); | |
144 | wake_up_state(p, TASK_INTERRUPTIBLE); | |
145 | } | |
146 | } | |
8a102eed | 147 | } |
02aaeb9b | 148 | } |
d5d8c597 RW |
149 | task_unlock(p); |
150 | return ret; | |
02aaeb9b RW |
151 | } |
152 | ||
a7ef7878 RW |
153 | static void cancel_freezing(struct task_struct *p) |
154 | { | |
155 | unsigned long flags; | |
156 | ||
157 | if (freezing(p)) { | |
158 | pr_debug(" clean up: %s\n", p->comm); | |
0c1eecfb | 159 | clear_freeze_flag(p); |
a7ef7878 | 160 | spin_lock_irqsave(&p->sighand->siglock, flags); |
7bb44ade | 161 | recalc_sigpending_and_wake(p); |
a7ef7878 RW |
162 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
163 | } | |
164 | } | |
165 | ||
e7cd8a72 | 166 | static int try_to_freeze_tasks(int freeze_user_space) |
1da177e4 | 167 | { |
1da177e4 | 168 | struct task_struct *g, *p; |
11b2ce2b RW |
169 | unsigned long end_time; |
170 | unsigned int todo; | |
3e1d1d28 | 171 | |
11b2ce2b | 172 | end_time = jiffies + TIMEOUT; |
1da177e4 | 173 | do { |
11b2ce2b | 174 | todo = 0; |
1da177e4 LT |
175 | read_lock(&tasklist_lock); |
176 | do_each_thread(g, p) { | |
0c1eecfb | 177 | if (frozen(p) || !freezeable(p)) |
1da177e4 | 178 | continue; |
11b2ce2b | 179 | |
d5d8c597 RW |
180 | if (p->state == TASK_TRACED && frozen(p->parent)) { |
181 | cancel_freezing(p); | |
182 | continue; | |
a7ef7878 | 183 | } |
d5d8c597 RW |
184 | |
185 | if (!freeze_task(p, freeze_user_space)) | |
186 | continue; | |
187 | ||
ba96a0c8 RW |
188 | if (!freezer_should_skip(p)) |
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 | |
6161b2ce | 197 | if (todo) { |
11b2ce2b RW |
198 | /* This does not unfreeze processes that are already frozen |
199 | * (we have slightly ugly calling convention in that respect, | |
200 | * and caller must call thaw_processes() if something fails), | |
201 | * but it cleans up leftover PF_FREEZE requests. | |
202 | */ | |
14b5b7cf | 203 | printk("\n"); |
0c1eecfb | 204 | printk(KERN_ERR "Freezing of %s timed out after %d seconds " |
11b2ce2b | 205 | "(%d tasks refusing to freeze):\n", |
0c1eecfb | 206 | freeze_user_space ? "user space " : "tasks ", |
11b2ce2b | 207 | TIMEOUT / HZ, todo); |
328616e3 | 208 | show_state(); |
6161b2ce | 209 | read_lock(&tasklist_lock); |
02aaeb9b | 210 | do_each_thread(g, p) { |
33e1c288 | 211 | task_lock(p); |
0c1eecfb | 212 | if (freezing(p) && !freezer_should_skip(p)) |
14b5b7cf | 213 | printk(KERN_ERR " %s\n", p->comm); |
a7ef7878 | 214 | cancel_freezing(p); |
33e1c288 | 215 | task_unlock(p); |
02aaeb9b | 216 | } while_each_thread(g, p); |
6161b2ce | 217 | read_unlock(&tasklist_lock); |
6161b2ce PM |
218 | } |
219 | ||
e7cd8a72 | 220 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
221 | } |
222 | ||
223 | /** | |
224 | * freeze_processes - tell processes to enter the refrigerator | |
11b2ce2b RW |
225 | */ |
226 | int freeze_processes(void) | |
227 | { | |
e7cd8a72 | 228 | int error; |
11b2ce2b RW |
229 | |
230 | printk("Stopping tasks ... "); | |
e7cd8a72 RW |
231 | error = try_to_freeze_tasks(FREEZER_USER_SPACE); |
232 | if (error) | |
233 | return error; | |
11b2ce2b | 234 | |
e7cd8a72 RW |
235 | error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); |
236 | if (error) | |
237 | return error; | |
11b2ce2b | 238 | |
14b5b7cf | 239 | printk("done.\n"); |
1da177e4 LT |
240 | BUG_ON(in_atomic()); |
241 | return 0; | |
242 | } | |
243 | ||
a9b6f562 | 244 | static void thaw_tasks(int thaw_user_space) |
1da177e4 LT |
245 | { |
246 | struct task_struct *g, *p; | |
247 | ||
1da177e4 | 248 | read_lock(&tasklist_lock); |
a9b6f562 RW |
249 | do_each_thread(g, p) { |
250 | if (!freezeable(p)) | |
251 | continue; | |
ff39593a | 252 | |
0c1eecfb | 253 | if (!p->mm == thaw_user_space) |
a9b6f562 | 254 | continue; |
1da177e4 | 255 | |
ba96a0c8 | 256 | thaw_process(p); |
a9b6f562 | 257 | } while_each_thread(g, p); |
1da177e4 | 258 | read_unlock(&tasklist_lock); |
a9b6f562 RW |
259 | } |
260 | ||
261 | void thaw_processes(void) | |
262 | { | |
263 | printk("Restarting tasks ... "); | |
264 | thaw_tasks(FREEZER_KERNEL_THREADS); | |
265 | thaw_tasks(FREEZER_USER_SPACE); | |
1da177e4 | 266 | schedule(); |
14b5b7cf | 267 | printk("done.\n"); |
1da177e4 LT |
268 | } |
269 | ||
270 | EXPORT_SYMBOL(refrigerator); |