mm, PM/Freezer: Disable OOM killer when tasks are frozen
[linux-2.6.git] / kernel / power / user.c
1 /*
2  * linux/kernel/power/user.c
3  *
4  * This file provides the user space interface for software suspend/resume.
5  *
6  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
7  *
8  * This file is released under the GPLv2.
9  *
10  */
11
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/miscdevice.h>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
21 #include <linux/pm.h>
22 #include <linux/fs.h>
23 #include <linux/console.h>
24 #include <linux/cpu.h>
25 #include <linux/freezer.h>
26 #include <linux/smp_lock.h>
27 #include <scsi/scsi_scan.h>
28
29 #include <asm/uaccess.h>
30
31 #include "power.h"
32
33 /*
34  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
35  * will be removed in the future.  They are only preserved here for
36  * compatibility with existing userland utilities.
37  */
38 #define SNAPSHOT_SET_SWAP_FILE  _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
39 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
40
41 #define PMOPS_PREPARE   1
42 #define PMOPS_ENTER     2
43 #define PMOPS_FINISH    3
44
45 /*
46  * NOTE: The following ioctl definitions are wrong and have been replaced with
47  * correct ones.  They are only preserved here for compatibility with existing
48  * userland utilities and will be removed in the future.
49  */
50 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
51 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
52 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
53 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
54
55
56 #define SNAPSHOT_MINOR  231
57
58 static struct snapshot_data {
59         struct snapshot_handle handle;
60         int swap;
61         int mode;
62         char frozen;
63         char ready;
64         char platform_support;
65 } snapshot_state;
66
67 atomic_t snapshot_device_available = ATOMIC_INIT(1);
68
69 static int snapshot_open(struct inode *inode, struct file *filp)
70 {
71         struct snapshot_data *data;
72         int error;
73
74         mutex_lock(&pm_mutex);
75
76         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
77                 error = -EBUSY;
78                 goto Unlock;
79         }
80
81         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
82                 atomic_inc(&snapshot_device_available);
83                 error = -ENOSYS;
84                 goto Unlock;
85         }
86         if(create_basic_memory_bitmaps()) {
87                 atomic_inc(&snapshot_device_available);
88                 error = -ENOMEM;
89                 goto Unlock;
90         }
91         nonseekable_open(inode, filp);
92         data = &snapshot_state;
93         filp->private_data = data;
94         memset(&data->handle, 0, sizeof(struct snapshot_handle));
95         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
96                 /* Hibernating.  The image device should be accessible. */
97                 data->swap = swsusp_resume_device ?
98                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
99                 data->mode = O_RDONLY;
100                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
101                 if (error)
102                         pm_notifier_call_chain(PM_POST_HIBERNATION);
103         } else {
104                 /*
105                  * Resuming.  We may need to wait for the image device to
106                  * appear.
107                  */
108                 wait_for_device_probe();
109                 scsi_complete_async_scans();
110
111                 data->swap = -1;
112                 data->mode = O_WRONLY;
113                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
114                 if (error)
115                         pm_notifier_call_chain(PM_POST_RESTORE);
116         }
117         if (error)
118                 atomic_inc(&snapshot_device_available);
119         data->frozen = 0;
120         data->ready = 0;
121         data->platform_support = 0;
122
123  Unlock:
124         mutex_unlock(&pm_mutex);
125
126         return error;
127 }
128
129 static int snapshot_release(struct inode *inode, struct file *filp)
130 {
131         struct snapshot_data *data;
132
133         mutex_lock(&pm_mutex);
134
135         swsusp_free();
136         free_basic_memory_bitmaps();
137         data = filp->private_data;
138         free_all_swap_pages(data->swap);
139         if (data->frozen)
140                 thaw_processes();
141         pm_notifier_call_chain(data->mode == O_WRONLY ?
142                         PM_POST_HIBERNATION : PM_POST_RESTORE);
143         atomic_inc(&snapshot_device_available);
144
145         mutex_unlock(&pm_mutex);
146
147         return 0;
148 }
149
150 static ssize_t snapshot_read(struct file *filp, char __user *buf,
151                              size_t count, loff_t *offp)
152 {
153         struct snapshot_data *data;
154         ssize_t res;
155
156         mutex_lock(&pm_mutex);
157
158         data = filp->private_data;
159         if (!data->ready) {
160                 res = -ENODATA;
161                 goto Unlock;
162         }
163         res = snapshot_read_next(&data->handle, count);
164         if (res > 0) {
165                 if (copy_to_user(buf, data_of(data->handle), res))
166                         res = -EFAULT;
167                 else
168                         *offp = data->handle.offset;
169         }
170
171  Unlock:
172         mutex_unlock(&pm_mutex);
173
174         return res;
175 }
176
177 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
178                               size_t count, loff_t *offp)
179 {
180         struct snapshot_data *data;
181         ssize_t res;
182
183         mutex_lock(&pm_mutex);
184
185         data = filp->private_data;
186         res = snapshot_write_next(&data->handle, count);
187         if (res > 0) {
188                 if (copy_from_user(data_of(data->handle), buf, res))
189                         res = -EFAULT;
190                 else
191                         *offp = data->handle.offset;
192         }
193
194         mutex_unlock(&pm_mutex);
195
196         return res;
197 }
198
199 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
200                                                         unsigned long arg)
201 {
202         int error = 0;
203         struct snapshot_data *data;
204         loff_t size;
205         sector_t offset;
206
207         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
208                 return -ENOTTY;
209         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
210                 return -ENOTTY;
211         if (!capable(CAP_SYS_ADMIN))
212                 return -EPERM;
213
214         if (!mutex_trylock(&pm_mutex))
215                 return -EBUSY;
216
217         data = filp->private_data;
218
219         switch (cmd) {
220
221         case SNAPSHOT_FREEZE:
222                 if (data->frozen)
223                         break;
224
225                 printk("Syncing filesystems ... ");
226                 sys_sync();
227                 printk("done.\n");
228
229                 error = usermodehelper_disable();
230                 if (error)
231                         break;
232
233                 error = freeze_processes();
234                 if (error) {
235                         thaw_processes();
236                         usermodehelper_enable();
237                 }
238                 if (!error)
239                         data->frozen = 1;
240                 break;
241
242         case SNAPSHOT_UNFREEZE:
243                 if (!data->frozen || data->ready)
244                         break;
245                 thaw_processes();
246                 usermodehelper_enable();
247                 data->frozen = 0;
248                 break;
249
250         case SNAPSHOT_CREATE_IMAGE:
251         case SNAPSHOT_ATOMIC_SNAPSHOT:
252                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
253                         error = -EPERM;
254                         break;
255                 }
256                 error = hibernation_snapshot(data->platform_support);
257                 if (!error)
258                         error = put_user(in_suspend, (int __user *)arg);
259                 if (!error)
260                         data->ready = 1;
261                 break;
262
263         case SNAPSHOT_ATOMIC_RESTORE:
264                 snapshot_write_finalize(&data->handle);
265                 if (data->mode != O_WRONLY || !data->frozen ||
266                     !snapshot_image_loaded(&data->handle)) {
267                         error = -EPERM;
268                         break;
269                 }
270                 error = hibernation_restore(data->platform_support);
271                 break;
272
273         case SNAPSHOT_FREE:
274                 swsusp_free();
275                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
276                 data->ready = 0;
277                 break;
278
279         case SNAPSHOT_PREF_IMAGE_SIZE:
280         case SNAPSHOT_SET_IMAGE_SIZE:
281                 image_size = arg;
282                 break;
283
284         case SNAPSHOT_GET_IMAGE_SIZE:
285                 if (!data->ready) {
286                         error = -ENODATA;
287                         break;
288                 }
289                 size = snapshot_get_image_size();
290                 size <<= PAGE_SHIFT;
291                 error = put_user(size, (loff_t __user *)arg);
292                 break;
293
294         case SNAPSHOT_AVAIL_SWAP_SIZE:
295         case SNAPSHOT_AVAIL_SWAP:
296                 size = count_swap_pages(data->swap, 1);
297                 size <<= PAGE_SHIFT;
298                 error = put_user(size, (loff_t __user *)arg);
299                 break;
300
301         case SNAPSHOT_ALLOC_SWAP_PAGE:
302         case SNAPSHOT_GET_SWAP_PAGE:
303                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
304                         error = -ENODEV;
305                         break;
306                 }
307                 offset = alloc_swapdev_block(data->swap);
308                 if (offset) {
309                         offset <<= PAGE_SHIFT;
310                         error = put_user(offset, (loff_t __user *)arg);
311                 } else {
312                         error = -ENOSPC;
313                 }
314                 break;
315
316         case SNAPSHOT_FREE_SWAP_PAGES:
317                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
318                         error = -ENODEV;
319                         break;
320                 }
321                 free_all_swap_pages(data->swap);
322                 break;
323
324         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
325                 if (!swsusp_swap_in_use()) {
326                         /*
327                          * User space encodes device types as two-byte values,
328                          * so we need to recode them
329                          */
330                         if (old_decode_dev(arg)) {
331                                 data->swap = swap_type_of(old_decode_dev(arg),
332                                                         0, NULL);
333                                 if (data->swap < 0)
334                                         error = -ENODEV;
335                         } else {
336                                 data->swap = -1;
337                                 error = -EINVAL;
338                         }
339                 } else {
340                         error = -EPERM;
341                 }
342                 break;
343
344         case SNAPSHOT_S2RAM:
345                 if (!data->frozen) {
346                         error = -EPERM;
347                         break;
348                 }
349                 /*
350                  * Tasks are frozen and the notifiers have been called with
351                  * PM_HIBERNATION_PREPARE
352                  */
353                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
354                 break;
355
356         case SNAPSHOT_PLATFORM_SUPPORT:
357                 data->platform_support = !!arg;
358                 break;
359
360         case SNAPSHOT_POWER_OFF:
361                 if (data->platform_support)
362                         error = hibernation_platform_enter();
363                 break;
364
365         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
366                 error = -EINVAL;
367
368                 switch (arg) {
369
370                 case PMOPS_PREPARE:
371                         data->platform_support = 1;
372                         error = 0;
373                         break;
374
375                 case PMOPS_ENTER:
376                         if (data->platform_support)
377                                 error = hibernation_platform_enter();
378                         break;
379
380                 case PMOPS_FINISH:
381                         if (data->platform_support)
382                                 error = 0;
383                         break;
384
385                 default:
386                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
387
388                 }
389                 break;
390
391         case SNAPSHOT_SET_SWAP_AREA:
392                 if (swsusp_swap_in_use()) {
393                         error = -EPERM;
394                 } else {
395                         struct resume_swap_area swap_area;
396                         dev_t swdev;
397
398                         error = copy_from_user(&swap_area, (void __user *)arg,
399                                         sizeof(struct resume_swap_area));
400                         if (error) {
401                                 error = -EFAULT;
402                                 break;
403                         }
404
405                         /*
406                          * User space encodes device types as two-byte values,
407                          * so we need to recode them
408                          */
409                         swdev = old_decode_dev(swap_area.dev);
410                         if (swdev) {
411                                 offset = swap_area.offset;
412                                 data->swap = swap_type_of(swdev, offset, NULL);
413                                 if (data->swap < 0)
414                                         error = -ENODEV;
415                         } else {
416                                 data->swap = -1;
417                                 error = -EINVAL;
418                         }
419                 }
420                 break;
421
422         default:
423                 error = -ENOTTY;
424
425         }
426
427         mutex_unlock(&pm_mutex);
428
429         return error;
430 }
431
432 static const struct file_operations snapshot_fops = {
433         .open = snapshot_open,
434         .release = snapshot_release,
435         .read = snapshot_read,
436         .write = snapshot_write,
437         .llseek = no_llseek,
438         .unlocked_ioctl = snapshot_ioctl,
439 };
440
441 static struct miscdevice snapshot_device = {
442         .minor = SNAPSHOT_MINOR,
443         .name = "snapshot",
444         .fops = &snapshot_fops,
445 };
446
447 static int __init snapshot_device_init(void)
448 {
449         return misc_register(&snapshot_device);
450 };
451
452 device_initcall(snapshot_device_init);