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d4cab38e GP |
1 | /* |
2 | * drivers/dma-buf/sync_file.c | |
3 | * | |
4 | * Copyright (C) 2012 Google, Inc. | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | */ | |
16 | ||
17 | #include <linux/export.h> | |
18 | #include <linux/file.h> | |
19 | #include <linux/fs.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/poll.h> | |
22 | #include <linux/sched.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/uaccess.h> | |
25 | #include <linux/anon_inodes.h> | |
460bfc41 GP |
26 | #include <linux/sync_file.h> |
27 | #include <uapi/linux/sync_file.h> | |
d4cab38e GP |
28 | |
29 | static const struct file_operations sync_file_fops; | |
30 | ||
31 | static struct sync_file *sync_file_alloc(int size) | |
32 | { | |
33 | struct sync_file *sync_file; | |
34 | ||
35 | sync_file = kzalloc(size, GFP_KERNEL); | |
36 | if (!sync_file) | |
37 | return NULL; | |
38 | ||
39 | sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops, | |
40 | sync_file, 0); | |
41 | if (IS_ERR(sync_file->file)) | |
42 | goto err; | |
43 | ||
44 | kref_init(&sync_file->kref); | |
45 | ||
46 | init_waitqueue_head(&sync_file->wq); | |
47 | ||
48 | return sync_file; | |
49 | ||
50 | err: | |
51 | kfree(sync_file); | |
52 | return NULL; | |
53 | } | |
54 | ||
55 | static void fence_check_cb_func(struct fence *f, struct fence_cb *cb) | |
56 | { | |
57 | struct sync_file_cb *check; | |
58 | struct sync_file *sync_file; | |
59 | ||
60 | check = container_of(cb, struct sync_file_cb, cb); | |
61 | sync_file = check->sync_file; | |
62 | ||
63 | if (atomic_dec_and_test(&sync_file->status)) | |
64 | wake_up_all(&sync_file->wq); | |
65 | } | |
66 | ||
67 | /** | |
c240a714 | 68 | * sync_file_create() - creates a sync file |
d4cab38e GP |
69 | * @fence: fence to add to the sync_fence |
70 | * | |
71 | * Creates a sync_file containg @fence. Once this is called, the sync_file | |
c240a714 GP |
72 | * takes ownership of @fence. The sync_file can be released with |
73 | * fput(sync_file->file). Returns the sync_file or NULL in case of error. | |
d4cab38e GP |
74 | */ |
75 | struct sync_file *sync_file_create(struct fence *fence) | |
76 | { | |
77 | struct sync_file *sync_file; | |
78 | ||
79 | sync_file = sync_file_alloc(offsetof(struct sync_file, cbs[1])); | |
80 | if (!sync_file) | |
81 | return NULL; | |
82 | ||
83 | sync_file->num_fences = 1; | |
84 | atomic_set(&sync_file->status, 1); | |
85 | snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%d-%d", | |
86 | fence->ops->get_driver_name(fence), | |
87 | fence->ops->get_timeline_name(fence), fence->context, | |
88 | fence->seqno); | |
89 | ||
90 | sync_file->cbs[0].fence = fence; | |
91 | sync_file->cbs[0].sync_file = sync_file; | |
92 | if (fence_add_callback(fence, &sync_file->cbs[0].cb, | |
93 | fence_check_cb_func)) | |
94 | atomic_dec(&sync_file->status); | |
95 | ||
96 | return sync_file; | |
97 | } | |
98 | EXPORT_SYMBOL(sync_file_create); | |
99 | ||
100 | /** | |
101 | * sync_file_fdget() - get a sync_file from an fd | |
102 | * @fd: fd referencing a fence | |
103 | * | |
104 | * Ensures @fd references a valid sync_file, increments the refcount of the | |
105 | * backing file. Returns the sync_file or NULL in case of error. | |
106 | */ | |
107 | static struct sync_file *sync_file_fdget(int fd) | |
108 | { | |
109 | struct file *file = fget(fd); | |
110 | ||
111 | if (!file) | |
112 | return NULL; | |
113 | ||
114 | if (file->f_op != &sync_file_fops) | |
115 | goto err; | |
116 | ||
117 | return file->private_data; | |
118 | ||
119 | err: | |
120 | fput(file); | |
121 | return NULL; | |
122 | } | |
123 | ||
124 | static void sync_file_add_pt(struct sync_file *sync_file, int *i, | |
125 | struct fence *fence) | |
126 | { | |
127 | sync_file->cbs[*i].fence = fence; | |
128 | sync_file->cbs[*i].sync_file = sync_file; | |
129 | ||
130 | if (!fence_add_callback(fence, &sync_file->cbs[*i].cb, | |
131 | fence_check_cb_func)) { | |
132 | fence_get(fence); | |
133 | (*i)++; | |
134 | } | |
135 | } | |
136 | ||
137 | /** | |
138 | * sync_file_merge() - merge two sync_files | |
139 | * @name: name of new fence | |
140 | * @a: sync_file a | |
141 | * @b: sync_file b | |
142 | * | |
143 | * Creates a new sync_file which contains copies of all the fences in both | |
144 | * @a and @b. @a and @b remain valid, independent sync_file. Returns the | |
145 | * new merged sync_file or NULL in case of error. | |
146 | */ | |
147 | static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, | |
148 | struct sync_file *b) | |
149 | { | |
150 | int num_fences = a->num_fences + b->num_fences; | |
151 | struct sync_file *sync_file; | |
152 | int i, i_a, i_b; | |
153 | unsigned long size = offsetof(struct sync_file, cbs[num_fences]); | |
154 | ||
155 | sync_file = sync_file_alloc(size); | |
156 | if (!sync_file) | |
157 | return NULL; | |
158 | ||
159 | atomic_set(&sync_file->status, num_fences); | |
160 | ||
161 | /* | |
162 | * Assume sync_file a and b are both ordered and have no | |
163 | * duplicates with the same context. | |
164 | * | |
165 | * If a sync_file can only be created with sync_file_merge | |
166 | * and sync_file_create, this is a reasonable assumption. | |
167 | */ | |
168 | for (i = i_a = i_b = 0; i_a < a->num_fences && i_b < b->num_fences; ) { | |
169 | struct fence *pt_a = a->cbs[i_a].fence; | |
170 | struct fence *pt_b = b->cbs[i_b].fence; | |
171 | ||
172 | if (pt_a->context < pt_b->context) { | |
173 | sync_file_add_pt(sync_file, &i, pt_a); | |
174 | ||
175 | i_a++; | |
176 | } else if (pt_a->context > pt_b->context) { | |
177 | sync_file_add_pt(sync_file, &i, pt_b); | |
178 | ||
179 | i_b++; | |
180 | } else { | |
181 | if (pt_a->seqno - pt_b->seqno <= INT_MAX) | |
182 | sync_file_add_pt(sync_file, &i, pt_a); | |
183 | else | |
184 | sync_file_add_pt(sync_file, &i, pt_b); | |
185 | ||
186 | i_a++; | |
187 | i_b++; | |
188 | } | |
189 | } | |
190 | ||
191 | for (; i_a < a->num_fences; i_a++) | |
192 | sync_file_add_pt(sync_file, &i, a->cbs[i_a].fence); | |
193 | ||
194 | for (; i_b < b->num_fences; i_b++) | |
195 | sync_file_add_pt(sync_file, &i, b->cbs[i_b].fence); | |
196 | ||
197 | if (num_fences > i) | |
198 | atomic_sub(num_fences - i, &sync_file->status); | |
199 | sync_file->num_fences = i; | |
200 | ||
201 | strlcpy(sync_file->name, name, sizeof(sync_file->name)); | |
202 | return sync_file; | |
203 | } | |
204 | ||
205 | static void sync_file_free(struct kref *kref) | |
206 | { | |
207 | struct sync_file *sync_file = container_of(kref, struct sync_file, | |
208 | kref); | |
209 | int i; | |
210 | ||
211 | for (i = 0; i < sync_file->num_fences; ++i) { | |
212 | fence_remove_callback(sync_file->cbs[i].fence, | |
213 | &sync_file->cbs[i].cb); | |
214 | fence_put(sync_file->cbs[i].fence); | |
215 | } | |
216 | ||
217 | kfree(sync_file); | |
218 | } | |
219 | ||
220 | static int sync_file_release(struct inode *inode, struct file *file) | |
221 | { | |
222 | struct sync_file *sync_file = file->private_data; | |
223 | ||
224 | kref_put(&sync_file->kref, sync_file_free); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | static unsigned int sync_file_poll(struct file *file, poll_table *wait) | |
229 | { | |
230 | struct sync_file *sync_file = file->private_data; | |
231 | int status; | |
232 | ||
233 | poll_wait(file, &sync_file->wq, wait); | |
234 | ||
235 | status = atomic_read(&sync_file->status); | |
236 | ||
237 | if (!status) | |
238 | return POLLIN; | |
239 | if (status < 0) | |
240 | return POLLERR; | |
241 | return 0; | |
242 | } | |
243 | ||
244 | static long sync_file_ioctl_merge(struct sync_file *sync_file, | |
92e06213 | 245 | unsigned long arg) |
d4cab38e GP |
246 | { |
247 | int fd = get_unused_fd_flags(O_CLOEXEC); | |
248 | int err; | |
249 | struct sync_file *fence2, *fence3; | |
250 | struct sync_merge_data data; | |
251 | ||
252 | if (fd < 0) | |
253 | return fd; | |
254 | ||
255 | if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { | |
256 | err = -EFAULT; | |
257 | goto err_put_fd; | |
258 | } | |
259 | ||
260 | if (data.flags || data.pad) { | |
261 | err = -EINVAL; | |
262 | goto err_put_fd; | |
263 | } | |
264 | ||
265 | fence2 = sync_file_fdget(data.fd2); | |
266 | if (!fence2) { | |
267 | err = -ENOENT; | |
268 | goto err_put_fd; | |
269 | } | |
270 | ||
271 | data.name[sizeof(data.name) - 1] = '\0'; | |
272 | fence3 = sync_file_merge(data.name, sync_file, fence2); | |
273 | if (!fence3) { | |
274 | err = -ENOMEM; | |
275 | goto err_put_fence2; | |
276 | } | |
277 | ||
278 | data.fence = fd; | |
279 | if (copy_to_user((void __user *)arg, &data, sizeof(data))) { | |
280 | err = -EFAULT; | |
281 | goto err_put_fence3; | |
282 | } | |
283 | ||
284 | fd_install(fd, fence3->file); | |
285 | fput(fence2->file); | |
286 | return 0; | |
287 | ||
288 | err_put_fence3: | |
289 | fput(fence3->file); | |
290 | ||
291 | err_put_fence2: | |
292 | fput(fence2->file); | |
293 | ||
294 | err_put_fd: | |
295 | put_unused_fd(fd); | |
296 | return err; | |
297 | } | |
298 | ||
299 | static void sync_fill_fence_info(struct fence *fence, | |
92e06213 | 300 | struct sync_fence_info *info) |
d4cab38e GP |
301 | { |
302 | strlcpy(info->obj_name, fence->ops->get_timeline_name(fence), | |
303 | sizeof(info->obj_name)); | |
304 | strlcpy(info->driver_name, fence->ops->get_driver_name(fence), | |
305 | sizeof(info->driver_name)); | |
306 | if (fence_is_signaled(fence)) | |
307 | info->status = fence->status >= 0 ? 1 : fence->status; | |
308 | else | |
309 | info->status = 0; | |
310 | info->timestamp_ns = ktime_to_ns(fence->timestamp); | |
311 | } | |
312 | ||
313 | static long sync_file_ioctl_fence_info(struct sync_file *sync_file, | |
92e06213 | 314 | unsigned long arg) |
d4cab38e GP |
315 | { |
316 | struct sync_file_info info; | |
317 | struct sync_fence_info *fence_info = NULL; | |
318 | __u32 size; | |
319 | int ret, i; | |
320 | ||
321 | if (copy_from_user(&info, (void __user *)arg, sizeof(info))) | |
322 | return -EFAULT; | |
323 | ||
324 | if (info.flags || info.pad) | |
325 | return -EINVAL; | |
326 | ||
327 | /* | |
328 | * Passing num_fences = 0 means that userspace doesn't want to | |
329 | * retrieve any sync_fence_info. If num_fences = 0 we skip filling | |
330 | * sync_fence_info and return the actual number of fences on | |
331 | * info->num_fences. | |
332 | */ | |
333 | if (!info.num_fences) | |
334 | goto no_fences; | |
335 | ||
336 | if (info.num_fences < sync_file->num_fences) | |
337 | return -EINVAL; | |
338 | ||
339 | size = sync_file->num_fences * sizeof(*fence_info); | |
340 | fence_info = kzalloc(size, GFP_KERNEL); | |
341 | if (!fence_info) | |
342 | return -ENOMEM; | |
343 | ||
344 | for (i = 0; i < sync_file->num_fences; ++i) | |
345 | sync_fill_fence_info(sync_file->cbs[i].fence, &fence_info[i]); | |
346 | ||
347 | if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, | |
348 | size)) { | |
349 | ret = -EFAULT; | |
350 | goto out; | |
351 | } | |
352 | ||
353 | no_fences: | |
354 | strlcpy(info.name, sync_file->name, sizeof(info.name)); | |
355 | info.status = atomic_read(&sync_file->status); | |
356 | if (info.status >= 0) | |
357 | info.status = !info.status; | |
358 | ||
359 | info.num_fences = sync_file->num_fences; | |
360 | ||
361 | if (copy_to_user((void __user *)arg, &info, sizeof(info))) | |
362 | ret = -EFAULT; | |
363 | else | |
364 | ret = 0; | |
365 | ||
366 | out: | |
367 | kfree(fence_info); | |
368 | ||
369 | return ret; | |
370 | } | |
371 | ||
372 | static long sync_file_ioctl(struct file *file, unsigned int cmd, | |
92e06213 | 373 | unsigned long arg) |
d4cab38e GP |
374 | { |
375 | struct sync_file *sync_file = file->private_data; | |
376 | ||
377 | switch (cmd) { | |
378 | case SYNC_IOC_MERGE: | |
379 | return sync_file_ioctl_merge(sync_file, arg); | |
380 | ||
381 | case SYNC_IOC_FILE_INFO: | |
382 | return sync_file_ioctl_fence_info(sync_file, arg); | |
383 | ||
384 | default: | |
385 | return -ENOTTY; | |
386 | } | |
387 | } | |
388 | ||
389 | static const struct file_operations sync_file_fops = { | |
390 | .release = sync_file_release, | |
391 | .poll = sync_file_poll, | |
392 | .unlocked_ioctl = sync_file_ioctl, | |
393 | .compat_ioctl = sync_file_ioctl, | |
394 | }; | |
395 |