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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>
26#include <linux/sync_file.h>
27#include <uapi/linux/sync_file.h>
28
29static const struct file_operations sync_file_fops;
30
31static struct sync_file *sync_file_alloc(void)
32{
33 struct sync_file *sync_file;
34
35 sync_file = kzalloc(sizeof(*sync_file), 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 INIT_LIST_HEAD(&sync_file->cb.node);
49
50 return sync_file;
51
52err:
53 kfree(sync_file);
54 return NULL;
55}
56
57static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb)
58{
59 struct sync_file *sync_file;
60
61 sync_file = container_of(cb, struct sync_file, cb);
62
63 wake_up_all(&sync_file->wq);
64}
65
66/**
67 * sync_file_create() - creates a sync file
68 * @fence: fence to add to the sync_fence
69 *
70 * Creates a sync_file containg @fence. Once this is called, the sync_file
71 * takes ownership of @fence. The sync_file can be released with
72 * fput(sync_file->file). Returns the sync_file or NULL in case of error.
73 */
74struct sync_file *sync_file_create(struct dma_fence *fence)
75{
76 struct sync_file *sync_file;
77
78 sync_file = sync_file_alloc();
79 if (!sync_file)
80 return NULL;
81
82 sync_file->fence = dma_fence_get(fence);
83
84 snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d",
85 fence->ops->get_driver_name(fence),
86 fence->ops->get_timeline_name(fence), fence->context,
87 fence->seqno);
88
89 return sync_file;
90}
91EXPORT_SYMBOL(sync_file_create);
92
93/**
94 * sync_file_fdget() - get a sync_file from an fd
95 * @fd: fd referencing a fence
96 *
97 * Ensures @fd references a valid sync_file, increments the refcount of the
98 * backing file. Returns the sync_file or NULL in case of error.
99 */
100static struct sync_file *sync_file_fdget(int fd)
101{
102 struct file *file = fget(fd);
103
104 if (!file)
105 return NULL;
106
107 if (file->f_op != &sync_file_fops)
108 goto err;
109
110 return file->private_data;
111
112err:
113 fput(file);
114 return NULL;
115}
116
117/**
118 * sync_file_get_fence - get the fence related to the sync_file fd
119 * @fd: sync_file fd to get the fence from
120 *
121 * Ensures @fd references a valid sync_file and returns a fence that
122 * represents all fence in the sync_file. On error NULL is returned.
123 */
124struct dma_fence *sync_file_get_fence(int fd)
125{
126 struct sync_file *sync_file;
127 struct dma_fence *fence;
128
129 sync_file = sync_file_fdget(fd);
130 if (!sync_file)
131 return NULL;
132
133 fence = dma_fence_get(sync_file->fence);
134 fput(sync_file->file);
135
136 return fence;
137}
138EXPORT_SYMBOL(sync_file_get_fence);
139
140static int sync_file_set_fence(struct sync_file *sync_file,
141 struct dma_fence **fences, int num_fences)
142{
143 struct dma_fence_array *array;
144
145 /*
146 * The reference for the fences in the new sync_file and held
147 * in add_fence() during the merge procedure, so for num_fences == 1
148 * we already own a new reference to the fence. For num_fence > 1
149 * we own the reference of the dma_fence_array creation.
150 */
151 if (num_fences == 1) {
152 sync_file->fence = fences[0];
153 kfree(fences);
154 } else {
155 array = dma_fence_array_create(num_fences, fences,
156 dma_fence_context_alloc(1),
157 1, false);
158 if (!array)
159 return -ENOMEM;
160
161 sync_file->fence = &array->base;
162 }
163
164 return 0;
165}
166
167static struct dma_fence **get_fences(struct sync_file *sync_file,
168 int *num_fences)
169{
170 if (dma_fence_is_array(sync_file->fence)) {
171 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
172
173 *num_fences = array->num_fences;
174 return array->fences;
175 }
176
177 *num_fences = 1;
178 return &sync_file->fence;
179}
180
181static void add_fence(struct dma_fence **fences,
182 int *i, struct dma_fence *fence)
183{
184 fences[*i] = fence;
185
186 if (!dma_fence_is_signaled(fence)) {
187 dma_fence_get(fence);
188 (*i)++;
189 }
190}
191
192/**
193 * sync_file_merge() - merge two sync_files
194 * @name: name of new fence
195 * @a: sync_file a
196 * @b: sync_file b
197 *
198 * Creates a new sync_file which contains copies of all the fences in both
199 * @a and @b. @a and @b remain valid, independent sync_file. Returns the
200 * new merged sync_file or NULL in case of error.
201 */
202static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
203 struct sync_file *b)
204{
205 struct sync_file *sync_file;
206 struct dma_fence **fences, **nfences, **a_fences, **b_fences;
207 int i, i_a, i_b, num_fences, a_num_fences, b_num_fences;
208
209 sync_file = sync_file_alloc();
210 if (!sync_file)
211 return NULL;
212
213 a_fences = get_fences(a, &a_num_fences);
214 b_fences = get_fences(b, &b_num_fences);
215 if (a_num_fences > INT_MAX - b_num_fences)
216 return NULL;
217
218 num_fences = a_num_fences + b_num_fences;
219
220 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
221 if (!fences)
222 goto err;
223
224 /*
225 * Assume sync_file a and b are both ordered and have no
226 * duplicates with the same context.
227 *
228 * If a sync_file can only be created with sync_file_merge
229 * and sync_file_create, this is a reasonable assumption.
230 */
231 for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
232 struct dma_fence *pt_a = a_fences[i_a];
233 struct dma_fence *pt_b = b_fences[i_b];
234
235 if (pt_a->context < pt_b->context) {
236 add_fence(fences, &i, pt_a);
237
238 i_a++;
239 } else if (pt_a->context > pt_b->context) {
240 add_fence(fences, &i, pt_b);
241
242 i_b++;
243 } else {
244 if (pt_a->seqno - pt_b->seqno <= INT_MAX)
245 add_fence(fences, &i, pt_a);
246 else
247 add_fence(fences, &i, pt_b);
248
249 i_a++;
250 i_b++;
251 }
252 }
253
254 for (; i_a < a_num_fences; i_a++)
255 add_fence(fences, &i, a_fences[i_a]);
256
257 for (; i_b < b_num_fences; i_b++)
258 add_fence(fences, &i, b_fences[i_b]);
259
260 if (i == 0)
261 fences[i++] = dma_fence_get(a_fences[0]);
262
263 if (num_fences > i) {
264 nfences = krealloc(fences, i * sizeof(*fences),
265 GFP_KERNEL);
266 if (!nfences)
267 goto err;
268
269 fences = nfences;
270 }
271
272 if (sync_file_set_fence(sync_file, fences, i) < 0) {
273 kfree(fences);
274 goto err;
275 }
276
277 strlcpy(sync_file->name, name, sizeof(sync_file->name));
278 return sync_file;
279
280err:
281 fput(sync_file->file);
282 return NULL;
283
284}
285
286static void sync_file_free(struct kref *kref)
287{
288 struct sync_file *sync_file = container_of(kref, struct sync_file,
289 kref);
290
291 if (test_bit(POLL_ENABLED, &sync_file->fence->flags))
292 dma_fence_remove_callback(sync_file->fence, &sync_file->cb);
293 dma_fence_put(sync_file->fence);
294 kfree(sync_file);
295}
296
297static int sync_file_release(struct inode *inode, struct file *file)
298{
299 struct sync_file *sync_file = file->private_data;
300
301 kref_put(&sync_file->kref, sync_file_free);
302 return 0;
303}
304
305static unsigned int sync_file_poll(struct file *file, poll_table *wait)
306{
307 struct sync_file *sync_file = file->private_data;
308
309 poll_wait(file, &sync_file->wq, wait);
310
311 if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
312 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb,
313 fence_check_cb_func) < 0)
314 wake_up_all(&sync_file->wq);
315 }
316
317 return dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0;
318}
319
320static long sync_file_ioctl_merge(struct sync_file *sync_file,
321 unsigned long arg)
322{
323 int fd = get_unused_fd_flags(O_CLOEXEC);
324 int err;
325 struct sync_file *fence2, *fence3;
326 struct sync_merge_data data;
327
328 if (fd < 0)
329 return fd;
330
331 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
332 err = -EFAULT;
333 goto err_put_fd;
334 }
335
336 if (data.flags || data.pad) {
337 err = -EINVAL;
338 goto err_put_fd;
339 }
340
341 fence2 = sync_file_fdget(data.fd2);
342 if (!fence2) {
343 err = -ENOENT;
344 goto err_put_fd;
345 }
346
347 data.name[sizeof(data.name) - 1] = '\0';
348 fence3 = sync_file_merge(data.name, sync_file, fence2);
349 if (!fence3) {
350 err = -ENOMEM;
351 goto err_put_fence2;
352 }
353
354 data.fence = fd;
355 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
356 err = -EFAULT;
357 goto err_put_fence3;
358 }
359
360 fd_install(fd, fence3->file);
361 fput(fence2->file);
362 return 0;
363
364err_put_fence3:
365 fput(fence3->file);
366
367err_put_fence2:
368 fput(fence2->file);
369
370err_put_fd:
371 put_unused_fd(fd);
372 return err;
373}
374
375static void sync_fill_fence_info(struct dma_fence *fence,
376 struct sync_fence_info *info)
377{
378 strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
379 sizeof(info->obj_name));
380 strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
381 sizeof(info->driver_name));
382 if (dma_fence_is_signaled(fence))
383 info->status = fence->status >= 0 ? 1 : fence->status;
384 else
385 info->status = 0;
386 info->timestamp_ns = ktime_to_ns(fence->timestamp);
387}
388
389static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
390 unsigned long arg)
391{
392 struct sync_file_info info;
393 struct sync_fence_info *fence_info = NULL;
394 struct dma_fence **fences;
395 __u32 size;
396 int num_fences, ret, i;
397
398 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
399 return -EFAULT;
400
401 if (info.flags || info.pad)
402 return -EINVAL;
403
404 fences = get_fences(sync_file, &num_fences);
405
406 /*
407 * Passing num_fences = 0 means that userspace doesn't want to
408 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
409 * sync_fence_info and return the actual number of fences on
410 * info->num_fences.
411 */
412 if (!info.num_fences)
413 goto no_fences;
414
415 if (info.num_fences < num_fences)
416 return -EINVAL;
417
418 size = num_fences * sizeof(*fence_info);
419 fence_info = kzalloc(size, GFP_KERNEL);
420 if (!fence_info)
421 return -ENOMEM;
422
423 for (i = 0; i < num_fences; i++)
424 sync_fill_fence_info(fences[i], &fence_info[i]);
425
426 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
427 size)) {
428 ret = -EFAULT;
429 goto out;
430 }
431
432no_fences:
433 strlcpy(info.name, sync_file->name, sizeof(info.name));
434 info.status = dma_fence_is_signaled(sync_file->fence);
435 info.num_fences = num_fences;
436
437 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
438 ret = -EFAULT;
439 else
440 ret = 0;
441
442out:
443 kfree(fence_info);
444
445 return ret;
446}
447
448static long sync_file_ioctl(struct file *file, unsigned int cmd,
449 unsigned long arg)
450{
451 struct sync_file *sync_file = file->private_data;
452
453 switch (cmd) {
454 case SYNC_IOC_MERGE:
455 return sync_file_ioctl_merge(sync_file, arg);
456
457 case SYNC_IOC_FILE_INFO:
458 return sync_file_ioctl_fence_info(sync_file, arg);
459
460 default:
461 return -ENOTTY;
462 }
463}
464
465static const struct file_operations sync_file_fops = {
466 .release = sync_file_release,
467 .poll = sync_file_poll,
468 .unlocked_ioctl = sync_file_ioctl,
469 .compat_ioctl = sync_file_ioctl,
470};
471