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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/power/user.c
4 *
5 * This file provides the user space interface for software suspend/resume.
6 *
7 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
8 */
9
10#include <linux/suspend.h>
11#include <linux/reboot.h>
12#include <linux/string.h>
13#include <linux/device.h>
14#include <linux/miscdevice.h>
15#include <linux/mm.h>
16#include <linux/swap.h>
17#include <linux/swapops.h>
18#include <linux/pm.h>
19#include <linux/fs.h>
20#include <linux/compat.h>
21#include <linux/console.h>
22#include <linux/cpu.h>
23#include <linux/freezer.h>
24
25#include <linux/uaccess.h>
26
27#include "power.h"
28
29
30static struct snapshot_data {
31 struct snapshot_handle handle;
32 int swap;
33 int mode;
34 bool frozen;
35 bool ready;
36 bool platform_support;
37 bool free_bitmaps;
38 struct inode *bd_inode;
39} snapshot_state;
40
41int is_hibernate_resume_dev(const struct inode *bd_inode)
42{
43 return hibernation_available() && snapshot_state.bd_inode == bd_inode;
44}
45
46static int snapshot_open(struct inode *inode, struct file *filp)
47{
48 struct snapshot_data *data;
49 int error, nr_calls = 0;
50
51 if (!hibernation_available())
52 return -EPERM;
53
54 lock_system_sleep();
55
56 if (!hibernate_acquire()) {
57 error = -EBUSY;
58 goto Unlock;
59 }
60
61 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
62 hibernate_release();
63 error = -ENOSYS;
64 goto Unlock;
65 }
66 nonseekable_open(inode, filp);
67 data = &snapshot_state;
68 filp->private_data = data;
69 memset(&data->handle, 0, sizeof(struct snapshot_handle));
70 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
71 /* Hibernating. The image device should be accessible. */
72 data->swap = swsusp_resume_device ?
73 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
74 data->mode = O_RDONLY;
75 data->free_bitmaps = false;
76 error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
77 if (error)
78 __pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL);
79 } else {
80 /*
81 * Resuming. We may need to wait for the image device to
82 * appear.
83 */
84 wait_for_device_probe();
85
86 data->swap = -1;
87 data->mode = O_WRONLY;
88 error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
89 if (!error) {
90 error = create_basic_memory_bitmaps();
91 data->free_bitmaps = !error;
92 } else
93 nr_calls--;
94
95 if (error)
96 __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
97 }
98 if (error)
99 hibernate_release();
100
101 data->frozen = false;
102 data->ready = false;
103 data->platform_support = false;
104 data->bd_inode = NULL;
105
106 Unlock:
107 unlock_system_sleep();
108
109 return error;
110}
111
112static int snapshot_release(struct inode *inode, struct file *filp)
113{
114 struct snapshot_data *data;
115
116 lock_system_sleep();
117
118 swsusp_free();
119 data = filp->private_data;
120 data->bd_inode = NULL;
121 free_all_swap_pages(data->swap);
122 if (data->frozen) {
123 pm_restore_gfp_mask();
124 free_basic_memory_bitmaps();
125 thaw_processes();
126 } else if (data->free_bitmaps) {
127 free_basic_memory_bitmaps();
128 }
129 pm_notifier_call_chain(data->mode == O_RDONLY ?
130 PM_POST_HIBERNATION : PM_POST_RESTORE);
131 hibernate_release();
132
133 unlock_system_sleep();
134
135 return 0;
136}
137
138static ssize_t snapshot_read(struct file *filp, char __user *buf,
139 size_t count, loff_t *offp)
140{
141 struct snapshot_data *data;
142 ssize_t res;
143 loff_t pg_offp = *offp & ~PAGE_MASK;
144
145 lock_system_sleep();
146
147 data = filp->private_data;
148 if (!data->ready) {
149 res = -ENODATA;
150 goto Unlock;
151 }
152 if (!pg_offp) { /* on page boundary? */
153 res = snapshot_read_next(&data->handle);
154 if (res <= 0)
155 goto Unlock;
156 } else {
157 res = PAGE_SIZE - pg_offp;
158 }
159
160 res = simple_read_from_buffer(buf, count, &pg_offp,
161 data_of(data->handle), res);
162 if (res > 0)
163 *offp += res;
164
165 Unlock:
166 unlock_system_sleep();
167
168 return res;
169}
170
171static ssize_t snapshot_write(struct file *filp, const char __user *buf,
172 size_t count, loff_t *offp)
173{
174 struct snapshot_data *data;
175 ssize_t res;
176 loff_t pg_offp = *offp & ~PAGE_MASK;
177
178 lock_system_sleep();
179
180 data = filp->private_data;
181
182 if (!pg_offp) {
183 res = snapshot_write_next(&data->handle);
184 if (res <= 0)
185 goto unlock;
186 } else {
187 res = PAGE_SIZE - pg_offp;
188 }
189
190 if (!data_of(data->handle)) {
191 res = -EINVAL;
192 goto unlock;
193 }
194
195 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
196 buf, count);
197 if (res > 0)
198 *offp += res;
199unlock:
200 unlock_system_sleep();
201
202 return res;
203}
204
205struct compat_resume_swap_area {
206 compat_loff_t offset;
207 u32 dev;
208} __packed;
209
210static int snapshot_set_swap_area(struct snapshot_data *data,
211 void __user *argp)
212{
213 struct block_device *bdev;
214 sector_t offset;
215 dev_t swdev;
216
217 if (swsusp_swap_in_use())
218 return -EPERM;
219
220 if (in_compat_syscall()) {
221 struct compat_resume_swap_area swap_area;
222
223 if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
224 return -EFAULT;
225 swdev = new_decode_dev(swap_area.dev);
226 offset = swap_area.offset;
227 } else {
228 struct resume_swap_area swap_area;
229
230 if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
231 return -EFAULT;
232 swdev = new_decode_dev(swap_area.dev);
233 offset = swap_area.offset;
234 }
235
236 /*
237 * User space encodes device types as two-byte values,
238 * so we need to recode them
239 */
240 if (!swdev) {
241 data->swap = -1;
242 return -EINVAL;
243 }
244 data->swap = swap_type_of(swdev, offset, &bdev);
245 if (data->swap < 0)
246 return -ENODEV;
247
248 data->bd_inode = bdev->bd_inode;
249 bdput(bdev);
250 return 0;
251}
252
253static long snapshot_ioctl(struct file *filp, unsigned int cmd,
254 unsigned long arg)
255{
256 int error = 0;
257 struct snapshot_data *data;
258 loff_t size;
259 sector_t offset;
260
261 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
262 return -ENOTTY;
263 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
264 return -ENOTTY;
265 if (!capable(CAP_SYS_ADMIN))
266 return -EPERM;
267
268 if (!mutex_trylock(&system_transition_mutex))
269 return -EBUSY;
270
271 lock_device_hotplug();
272 data = filp->private_data;
273
274 switch (cmd) {
275
276 case SNAPSHOT_FREEZE:
277 if (data->frozen)
278 break;
279
280 ksys_sync_helper();
281
282 error = freeze_processes();
283 if (error)
284 break;
285
286 error = create_basic_memory_bitmaps();
287 if (error)
288 thaw_processes();
289 else
290 data->frozen = true;
291
292 break;
293
294 case SNAPSHOT_UNFREEZE:
295 if (!data->frozen || data->ready)
296 break;
297 pm_restore_gfp_mask();
298 free_basic_memory_bitmaps();
299 data->free_bitmaps = false;
300 thaw_processes();
301 data->frozen = false;
302 break;
303
304 case SNAPSHOT_CREATE_IMAGE:
305 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
306 error = -EPERM;
307 break;
308 }
309 pm_restore_gfp_mask();
310 error = hibernation_snapshot(data->platform_support);
311 if (!error) {
312 error = put_user(in_suspend, (int __user *)arg);
313 data->ready = !freezer_test_done && !error;
314 freezer_test_done = false;
315 }
316 break;
317
318 case SNAPSHOT_ATOMIC_RESTORE:
319 snapshot_write_finalize(&data->handle);
320 if (data->mode != O_WRONLY || !data->frozen ||
321 !snapshot_image_loaded(&data->handle)) {
322 error = -EPERM;
323 break;
324 }
325 error = hibernation_restore(data->platform_support);
326 break;
327
328 case SNAPSHOT_FREE:
329 swsusp_free();
330 memset(&data->handle, 0, sizeof(struct snapshot_handle));
331 data->ready = false;
332 /*
333 * It is necessary to thaw kernel threads here, because
334 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
335 * SNAPSHOT_FREE. In that case, if kernel threads were not
336 * thawed, the preallocation of memory carried out by
337 * hibernation_snapshot() might run into problems (i.e. it
338 * might fail or even deadlock).
339 */
340 thaw_kernel_threads();
341 break;
342
343 case SNAPSHOT_PREF_IMAGE_SIZE:
344 image_size = arg;
345 break;
346
347 case SNAPSHOT_GET_IMAGE_SIZE:
348 if (!data->ready) {
349 error = -ENODATA;
350 break;
351 }
352 size = snapshot_get_image_size();
353 size <<= PAGE_SHIFT;
354 error = put_user(size, (loff_t __user *)arg);
355 break;
356
357 case SNAPSHOT_AVAIL_SWAP_SIZE:
358 size = count_swap_pages(data->swap, 1);
359 size <<= PAGE_SHIFT;
360 error = put_user(size, (loff_t __user *)arg);
361 break;
362
363 case SNAPSHOT_ALLOC_SWAP_PAGE:
364 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
365 error = -ENODEV;
366 break;
367 }
368 offset = alloc_swapdev_block(data->swap);
369 if (offset) {
370 offset <<= PAGE_SHIFT;
371 error = put_user(offset, (loff_t __user *)arg);
372 } else {
373 error = -ENOSPC;
374 }
375 break;
376
377 case SNAPSHOT_FREE_SWAP_PAGES:
378 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
379 error = -ENODEV;
380 break;
381 }
382 free_all_swap_pages(data->swap);
383 break;
384
385 case SNAPSHOT_S2RAM:
386 if (!data->frozen) {
387 error = -EPERM;
388 break;
389 }
390 /*
391 * Tasks are frozen and the notifiers have been called with
392 * PM_HIBERNATION_PREPARE
393 */
394 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
395 data->ready = false;
396 break;
397
398 case SNAPSHOT_PLATFORM_SUPPORT:
399 data->platform_support = !!arg;
400 break;
401
402 case SNAPSHOT_POWER_OFF:
403 if (data->platform_support)
404 error = hibernation_platform_enter();
405 break;
406
407 case SNAPSHOT_SET_SWAP_AREA:
408 error = snapshot_set_swap_area(data, (void __user *)arg);
409 break;
410
411 default:
412 error = -ENOTTY;
413
414 }
415
416 unlock_device_hotplug();
417 mutex_unlock(&system_transition_mutex);
418
419 return error;
420}
421
422#ifdef CONFIG_COMPAT
423static long
424snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
425{
426 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
427
428 switch (cmd) {
429 case SNAPSHOT_GET_IMAGE_SIZE:
430 case SNAPSHOT_AVAIL_SWAP_SIZE:
431 case SNAPSHOT_ALLOC_SWAP_PAGE:
432 case SNAPSHOT_CREATE_IMAGE:
433 case SNAPSHOT_SET_SWAP_AREA:
434 return snapshot_ioctl(file, cmd,
435 (unsigned long) compat_ptr(arg));
436 default:
437 return snapshot_ioctl(file, cmd, arg);
438 }
439}
440#endif /* CONFIG_COMPAT */
441
442static const struct file_operations snapshot_fops = {
443 .open = snapshot_open,
444 .release = snapshot_release,
445 .read = snapshot_read,
446 .write = snapshot_write,
447 .llseek = no_llseek,
448 .unlocked_ioctl = snapshot_ioctl,
449#ifdef CONFIG_COMPAT
450 .compat_ioctl = snapshot_compat_ioctl,
451#endif
452};
453
454static struct miscdevice snapshot_device = {
455 .minor = SNAPSHOT_MINOR,
456 .name = "snapshot",
457 .fops = &snapshot_fops,
458};
459
460static int __init snapshot_device_init(void)
461{
462 return misc_register(&snapshot_device);
463};
464
465device_initcall(snapshot_device_init);
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/compat.h>
24#include <linux/console.h>
25#include <linux/cpu.h>
26#include <linux/freezer.h>
27
28#include <asm/uaccess.h>
29
30#include "power.h"
31
32
33#define SNAPSHOT_MINOR 231
34
35static struct snapshot_data {
36 struct snapshot_handle handle;
37 int swap;
38 int mode;
39 char frozen;
40 char ready;
41 char platform_support;
42} snapshot_state;
43
44atomic_t snapshot_device_available = ATOMIC_INIT(1);
45
46static int snapshot_open(struct inode *inode, struct file *filp)
47{
48 struct snapshot_data *data;
49 int error;
50
51 lock_system_sleep();
52
53 if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
54 error = -EBUSY;
55 goto Unlock;
56 }
57
58 if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
59 atomic_inc(&snapshot_device_available);
60 error = -ENOSYS;
61 goto Unlock;
62 }
63 if(create_basic_memory_bitmaps()) {
64 atomic_inc(&snapshot_device_available);
65 error = -ENOMEM;
66 goto Unlock;
67 }
68 nonseekable_open(inode, filp);
69 data = &snapshot_state;
70 filp->private_data = data;
71 memset(&data->handle, 0, sizeof(struct snapshot_handle));
72 if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
73 /* Hibernating. The image device should be accessible. */
74 data->swap = swsusp_resume_device ?
75 swap_type_of(swsusp_resume_device, 0, NULL) : -1;
76 data->mode = O_RDONLY;
77 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
78 if (error)
79 pm_notifier_call_chain(PM_POST_HIBERNATION);
80 } else {
81 /*
82 * Resuming. We may need to wait for the image device to
83 * appear.
84 */
85 wait_for_device_probe();
86
87 data->swap = -1;
88 data->mode = O_WRONLY;
89 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
90 if (error)
91 pm_notifier_call_chain(PM_POST_RESTORE);
92 }
93 if (error) {
94 free_basic_memory_bitmaps();
95 atomic_inc(&snapshot_device_available);
96 }
97 data->frozen = 0;
98 data->ready = 0;
99 data->platform_support = 0;
100
101 Unlock:
102 unlock_system_sleep();
103
104 return error;
105}
106
107static int snapshot_release(struct inode *inode, struct file *filp)
108{
109 struct snapshot_data *data;
110
111 lock_system_sleep();
112
113 swsusp_free();
114 free_basic_memory_bitmaps();
115 data = filp->private_data;
116 free_all_swap_pages(data->swap);
117 if (data->frozen) {
118 pm_restore_gfp_mask();
119 thaw_processes();
120 }
121 pm_notifier_call_chain(data->mode == O_RDONLY ?
122 PM_POST_HIBERNATION : PM_POST_RESTORE);
123 atomic_inc(&snapshot_device_available);
124
125 unlock_system_sleep();
126
127 return 0;
128}
129
130static ssize_t snapshot_read(struct file *filp, char __user *buf,
131 size_t count, loff_t *offp)
132{
133 struct snapshot_data *data;
134 ssize_t res;
135 loff_t pg_offp = *offp & ~PAGE_MASK;
136
137 lock_system_sleep();
138
139 data = filp->private_data;
140 if (!data->ready) {
141 res = -ENODATA;
142 goto Unlock;
143 }
144 if (!pg_offp) { /* on page boundary? */
145 res = snapshot_read_next(&data->handle);
146 if (res <= 0)
147 goto Unlock;
148 } else {
149 res = PAGE_SIZE - pg_offp;
150 }
151
152 res = simple_read_from_buffer(buf, count, &pg_offp,
153 data_of(data->handle), res);
154 if (res > 0)
155 *offp += res;
156
157 Unlock:
158 unlock_system_sleep();
159
160 return res;
161}
162
163static ssize_t snapshot_write(struct file *filp, const char __user *buf,
164 size_t count, loff_t *offp)
165{
166 struct snapshot_data *data;
167 ssize_t res;
168 loff_t pg_offp = *offp & ~PAGE_MASK;
169
170 lock_system_sleep();
171
172 data = filp->private_data;
173
174 if (!pg_offp) {
175 res = snapshot_write_next(&data->handle);
176 if (res <= 0)
177 goto unlock;
178 } else {
179 res = PAGE_SIZE - pg_offp;
180 }
181
182 res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
183 buf, count);
184 if (res > 0)
185 *offp += res;
186unlock:
187 unlock_system_sleep();
188
189 return res;
190}
191
192static long snapshot_ioctl(struct file *filp, unsigned int cmd,
193 unsigned long arg)
194{
195 int error = 0;
196 struct snapshot_data *data;
197 loff_t size;
198 sector_t offset;
199
200 if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
201 return -ENOTTY;
202 if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
203 return -ENOTTY;
204 if (!capable(CAP_SYS_ADMIN))
205 return -EPERM;
206
207 if (!mutex_trylock(&pm_mutex))
208 return -EBUSY;
209
210 data = filp->private_data;
211
212 switch (cmd) {
213
214 case SNAPSHOT_FREEZE:
215 if (data->frozen)
216 break;
217
218 printk("Syncing filesystems ... ");
219 sys_sync();
220 printk("done.\n");
221
222 error = freeze_processes();
223 if (!error)
224 data->frozen = 1;
225 break;
226
227 case SNAPSHOT_UNFREEZE:
228 if (!data->frozen || data->ready)
229 break;
230 pm_restore_gfp_mask();
231 thaw_processes();
232 data->frozen = 0;
233 break;
234
235 case SNAPSHOT_CREATE_IMAGE:
236 if (data->mode != O_RDONLY || !data->frozen || data->ready) {
237 error = -EPERM;
238 break;
239 }
240 pm_restore_gfp_mask();
241 error = hibernation_snapshot(data->platform_support);
242 if (!error) {
243 error = put_user(in_suspend, (int __user *)arg);
244 data->ready = !freezer_test_done && !error;
245 freezer_test_done = false;
246 }
247 break;
248
249 case SNAPSHOT_ATOMIC_RESTORE:
250 snapshot_write_finalize(&data->handle);
251 if (data->mode != O_WRONLY || !data->frozen ||
252 !snapshot_image_loaded(&data->handle)) {
253 error = -EPERM;
254 break;
255 }
256 error = hibernation_restore(data->platform_support);
257 break;
258
259 case SNAPSHOT_FREE:
260 swsusp_free();
261 memset(&data->handle, 0, sizeof(struct snapshot_handle));
262 data->ready = 0;
263 /*
264 * It is necessary to thaw kernel threads here, because
265 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
266 * SNAPSHOT_FREE. In that case, if kernel threads were not
267 * thawed, the preallocation of memory carried out by
268 * hibernation_snapshot() might run into problems (i.e. it
269 * might fail or even deadlock).
270 */
271 thaw_kernel_threads();
272 break;
273
274 case SNAPSHOT_PREF_IMAGE_SIZE:
275 image_size = arg;
276 break;
277
278 case SNAPSHOT_GET_IMAGE_SIZE:
279 if (!data->ready) {
280 error = -ENODATA;
281 break;
282 }
283 size = snapshot_get_image_size();
284 size <<= PAGE_SHIFT;
285 error = put_user(size, (loff_t __user *)arg);
286 break;
287
288 case SNAPSHOT_AVAIL_SWAP_SIZE:
289 size = count_swap_pages(data->swap, 1);
290 size <<= PAGE_SHIFT;
291 error = put_user(size, (loff_t __user *)arg);
292 break;
293
294 case SNAPSHOT_ALLOC_SWAP_PAGE:
295 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
296 error = -ENODEV;
297 break;
298 }
299 offset = alloc_swapdev_block(data->swap);
300 if (offset) {
301 offset <<= PAGE_SHIFT;
302 error = put_user(offset, (loff_t __user *)arg);
303 } else {
304 error = -ENOSPC;
305 }
306 break;
307
308 case SNAPSHOT_FREE_SWAP_PAGES:
309 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
310 error = -ENODEV;
311 break;
312 }
313 free_all_swap_pages(data->swap);
314 break;
315
316 case SNAPSHOT_S2RAM:
317 if (!data->frozen) {
318 error = -EPERM;
319 break;
320 }
321 /*
322 * Tasks are frozen and the notifiers have been called with
323 * PM_HIBERNATION_PREPARE
324 */
325 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
326 data->ready = 0;
327 break;
328
329 case SNAPSHOT_PLATFORM_SUPPORT:
330 data->platform_support = !!arg;
331 break;
332
333 case SNAPSHOT_POWER_OFF:
334 if (data->platform_support)
335 error = hibernation_platform_enter();
336 break;
337
338 case SNAPSHOT_SET_SWAP_AREA:
339 if (swsusp_swap_in_use()) {
340 error = -EPERM;
341 } else {
342 struct resume_swap_area swap_area;
343 dev_t swdev;
344
345 error = copy_from_user(&swap_area, (void __user *)arg,
346 sizeof(struct resume_swap_area));
347 if (error) {
348 error = -EFAULT;
349 break;
350 }
351
352 /*
353 * User space encodes device types as two-byte values,
354 * so we need to recode them
355 */
356 swdev = new_decode_dev(swap_area.dev);
357 if (swdev) {
358 offset = swap_area.offset;
359 data->swap = swap_type_of(swdev, offset, NULL);
360 if (data->swap < 0)
361 error = -ENODEV;
362 } else {
363 data->swap = -1;
364 error = -EINVAL;
365 }
366 }
367 break;
368
369 default:
370 error = -ENOTTY;
371
372 }
373
374 mutex_unlock(&pm_mutex);
375
376 return error;
377}
378
379#ifdef CONFIG_COMPAT
380
381struct compat_resume_swap_area {
382 compat_loff_t offset;
383 u32 dev;
384} __packed;
385
386static long
387snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
388{
389 BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
390
391 switch (cmd) {
392 case SNAPSHOT_GET_IMAGE_SIZE:
393 case SNAPSHOT_AVAIL_SWAP_SIZE:
394 case SNAPSHOT_ALLOC_SWAP_PAGE: {
395 compat_loff_t __user *uoffset = compat_ptr(arg);
396 loff_t offset;
397 mm_segment_t old_fs;
398 int err;
399
400 old_fs = get_fs();
401 set_fs(KERNEL_DS);
402 err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
403 set_fs(old_fs);
404 if (!err && put_user(offset, uoffset))
405 err = -EFAULT;
406 return err;
407 }
408
409 case SNAPSHOT_CREATE_IMAGE:
410 return snapshot_ioctl(file, cmd,
411 (unsigned long) compat_ptr(arg));
412
413 case SNAPSHOT_SET_SWAP_AREA: {
414 struct compat_resume_swap_area __user *u_swap_area =
415 compat_ptr(arg);
416 struct resume_swap_area swap_area;
417 mm_segment_t old_fs;
418 int err;
419
420 err = get_user(swap_area.offset, &u_swap_area->offset);
421 err |= get_user(swap_area.dev, &u_swap_area->dev);
422 if (err)
423 return -EFAULT;
424 old_fs = get_fs();
425 set_fs(KERNEL_DS);
426 err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
427 (unsigned long) &swap_area);
428 set_fs(old_fs);
429 return err;
430 }
431
432 default:
433 return snapshot_ioctl(file, cmd, arg);
434 }
435}
436
437#endif /* CONFIG_COMPAT */
438
439static const struct file_operations snapshot_fops = {
440 .open = snapshot_open,
441 .release = snapshot_release,
442 .read = snapshot_read,
443 .write = snapshot_write,
444 .llseek = no_llseek,
445 .unlocked_ioctl = snapshot_ioctl,
446#ifdef CONFIG_COMPAT
447 .compat_ioctl = snapshot_compat_ioctl,
448#endif
449};
450
451static struct miscdevice snapshot_device = {
452 .minor = SNAPSHOT_MINOR,
453 .name = "snapshot",
454 .fops = &snapshot_fops,
455};
456
457static int __init snapshot_device_init(void)
458{
459 return misc_register(&snapshot_device);
460};
461
462device_initcall(snapshot_device_init);