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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/dma-buf/sync_file.c
4 *
5 * Copyright (C) 2012 Google, Inc.
6 */
7
8#include <linux/dma-fence-unwrap.h>
9#include <linux/export.h>
10#include <linux/file.h>
11#include <linux/fs.h>
12#include <linux/kernel.h>
13#include <linux/poll.h>
14#include <linux/sched.h>
15#include <linux/slab.h>
16#include <linux/uaccess.h>
17#include <linux/anon_inodes.h>
18#include <linux/sync_file.h>
19#include <uapi/linux/sync_file.h>
20
21static const struct file_operations sync_file_fops;
22
23static struct sync_file *sync_file_alloc(void)
24{
25 struct sync_file *sync_file;
26
27 sync_file = kzalloc_obj(*sync_file);
28 if (!sync_file)
29 return NULL;
30
31 sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops,
32 sync_file, 0);
33 if (IS_ERR(sync_file->file))
34 goto err;
35
36 init_waitqueue_head(&sync_file->wq);
37
38 INIT_LIST_HEAD(&sync_file->cb.node);
39
40 return sync_file;
41
42err:
43 kfree(sync_file);
44 return NULL;
45}
46
47static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb)
48{
49 struct sync_file *sync_file;
50
51 sync_file = container_of(cb, struct sync_file, cb);
52
53 wake_up_all(&sync_file->wq);
54}
55
56/**
57 * sync_file_create() - creates a sync file
58 * @fence: fence to add to the sync_fence
59 *
60 * Creates a sync_file containg @fence. This function acquires and additional
61 * reference of @fence for the newly-created &sync_file, if it succeeds. The
62 * sync_file can be released with fput(sync_file->file). Returns the
63 * sync_file or NULL in case of error.
64 */
65struct sync_file *sync_file_create(struct dma_fence *fence)
66{
67 struct sync_file *sync_file;
68
69 sync_file = sync_file_alloc();
70 if (!sync_file)
71 return NULL;
72
73 sync_file->fence = dma_fence_get(fence);
74
75 return sync_file;
76}
77EXPORT_SYMBOL(sync_file_create);
78
79static struct sync_file *sync_file_fdget(int fd)
80{
81 struct file *file = fget(fd);
82
83 if (!file)
84 return NULL;
85
86 if (file->f_op != &sync_file_fops)
87 goto err;
88
89 return file->private_data;
90
91err:
92 fput(file);
93 return NULL;
94}
95
96/**
97 * sync_file_get_fence - get the fence related to the sync_file fd
98 * @fd: sync_file fd to get the fence from
99 *
100 * Ensures @fd references a valid sync_file and returns a fence that
101 * represents all fence in the sync_file. On error NULL is returned.
102 */
103struct dma_fence *sync_file_get_fence(int fd)
104{
105 struct sync_file *sync_file;
106 struct dma_fence *fence;
107
108 sync_file = sync_file_fdget(fd);
109 if (!sync_file)
110 return NULL;
111
112 fence = dma_fence_get(sync_file->fence);
113 fput(sync_file->file);
114
115 return fence;
116}
117EXPORT_SYMBOL(sync_file_get_fence);
118
119/**
120 * sync_file_get_name - get the name of the sync_file
121 * @sync_file: sync_file to get the fence from
122 * @buf: destination buffer to copy sync_file name into
123 * @len: available size of destination buffer.
124 *
125 * Each sync_file may have a name assigned either by the user (when merging
126 * sync_files together) or created from the fence it contains. In the latter
127 * case construction of the name is deferred until use, and so requires
128 * sync_file_get_name().
129 *
130 * Returns: a string representing the name.
131 */
132char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len)
133{
134 if (sync_file->user_name[0]) {
135 strscpy(buf, sync_file->user_name, len);
136 } else {
137 struct dma_fence *fence = sync_file->fence;
138 const char __rcu *timeline;
139 const char __rcu *driver;
140
141 rcu_read_lock();
142 driver = dma_fence_driver_name(fence);
143 timeline = dma_fence_timeline_name(fence);
144 snprintf(buf, len, "%s-%s%llu-%lld",
145 rcu_dereference(driver),
146 rcu_dereference(timeline),
147 fence->context,
148 fence->seqno);
149 rcu_read_unlock();
150 }
151
152 return buf;
153}
154
155/**
156 * sync_file_merge() - merge two sync_files
157 * @name: name of new fence
158 * @a: sync_file a
159 * @b: sync_file b
160 *
161 * Creates a new sync_file which contains copies of all the fences in both
162 * @a and @b. @a and @b remain valid, independent sync_file. Returns the
163 * new merged sync_file or NULL in case of error.
164 */
165static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
166 struct sync_file *b)
167{
168 struct sync_file *sync_file;
169 struct dma_fence *fence;
170
171 sync_file = sync_file_alloc();
172 if (!sync_file)
173 return NULL;
174
175 fence = dma_fence_unwrap_merge(a->fence, b->fence);
176 if (!fence) {
177 fput(sync_file->file);
178 return NULL;
179 }
180 sync_file->fence = fence;
181 strscpy(sync_file->user_name, name, sizeof(sync_file->user_name));
182 return sync_file;
183}
184
185static int sync_file_release(struct inode *inode, struct file *file)
186{
187 struct sync_file *sync_file = file->private_data;
188
189 if (test_bit(POLL_ENABLED, &sync_file->flags))
190 dma_fence_remove_callback(sync_file->fence, &sync_file->cb);
191 dma_fence_put(sync_file->fence);
192 kfree(sync_file);
193
194 return 0;
195}
196
197static __poll_t sync_file_poll(struct file *file, poll_table *wait)
198{
199 struct sync_file *sync_file = file->private_data;
200
201 poll_wait(file, &sync_file->wq, wait);
202
203 if (list_empty(&sync_file->cb.node) &&
204 !test_and_set_bit(POLL_ENABLED, &sync_file->flags)) {
205 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb,
206 fence_check_cb_func) < 0)
207 wake_up_all(&sync_file->wq);
208 }
209
210 return dma_fence_is_signaled(sync_file->fence) ? EPOLLIN : 0;
211}
212
213static long sync_file_ioctl_merge(struct sync_file *sync_file,
214 unsigned long arg)
215{
216 int fd = get_unused_fd_flags(O_CLOEXEC);
217 int err;
218 struct sync_file *fence2, *fence3;
219 struct sync_merge_data data;
220
221 if (fd < 0)
222 return fd;
223
224 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
225 err = -EFAULT;
226 goto err_put_fd;
227 }
228
229 if (data.flags || data.pad) {
230 err = -EINVAL;
231 goto err_put_fd;
232 }
233
234 fence2 = sync_file_fdget(data.fd2);
235 if (!fence2) {
236 err = -ENOENT;
237 goto err_put_fd;
238 }
239
240 data.name[sizeof(data.name) - 1] = '\0';
241 fence3 = sync_file_merge(data.name, sync_file, fence2);
242 if (!fence3) {
243 err = -ENOMEM;
244 goto err_put_fence2;
245 }
246
247 data.fence = fd;
248 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
249 err = -EFAULT;
250 goto err_put_fence3;
251 }
252
253 fd_install(fd, fence3->file);
254 fput(fence2->file);
255 return 0;
256
257err_put_fence3:
258 fput(fence3->file);
259
260err_put_fence2:
261 fput(fence2->file);
262
263err_put_fd:
264 put_unused_fd(fd);
265 return err;
266}
267
268static int sync_fill_fence_info(struct dma_fence *fence,
269 struct sync_fence_info *info)
270{
271 const char __rcu *timeline;
272 const char __rcu *driver;
273
274 rcu_read_lock();
275
276 driver = dma_fence_driver_name(fence);
277 timeline = dma_fence_timeline_name(fence);
278
279 strscpy(info->obj_name, rcu_dereference(timeline),
280 sizeof(info->obj_name));
281 strscpy(info->driver_name, rcu_dereference(driver),
282 sizeof(info->driver_name));
283
284 info->status = dma_fence_get_status(fence);
285 info->timestamp_ns =
286 dma_fence_is_signaled(fence) ?
287 ktime_to_ns(dma_fence_timestamp(fence)) :
288 ktime_set(0, 0);
289
290 rcu_read_unlock();
291
292 return info->status;
293}
294
295static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
296 unsigned long arg)
297{
298 struct sync_fence_info *fence_info = NULL;
299 struct dma_fence_unwrap iter;
300 struct sync_file_info info;
301 unsigned int num_fences;
302 struct dma_fence *fence;
303 int ret;
304 __u32 size;
305
306 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
307 return -EFAULT;
308
309 if (info.flags || info.pad)
310 return -EINVAL;
311
312 num_fences = 0;
313 dma_fence_unwrap_for_each(fence, &iter, sync_file->fence)
314 ++num_fences;
315
316 /*
317 * Passing num_fences = 0 means that userspace doesn't want to
318 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
319 * sync_fence_info and return the actual number of fences on
320 * info->num_fences.
321 */
322 if (!info.num_fences) {
323 info.status = dma_fence_get_status(sync_file->fence);
324 goto no_fences;
325 } else {
326 info.status = 1;
327 }
328
329 if (info.num_fences < num_fences)
330 return -EINVAL;
331
332 size = num_fences * sizeof(*fence_info);
333 fence_info = kzalloc(size, GFP_KERNEL);
334 if (!fence_info)
335 return -ENOMEM;
336
337 num_fences = 0;
338 dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) {
339 int status;
340
341 status = sync_fill_fence_info(fence, &fence_info[num_fences++]);
342 info.status = info.status <= 0 ? info.status : status;
343 }
344
345 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
346 size)) {
347 ret = -EFAULT;
348 goto out;
349 }
350
351no_fences:
352 sync_file_get_name(sync_file, info.name, sizeof(info.name));
353 info.num_fences = num_fences;
354
355 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
356 ret = -EFAULT;
357 else
358 ret = 0;
359
360out:
361 kfree(fence_info);
362
363 return ret;
364}
365
366static int sync_file_ioctl_set_deadline(struct sync_file *sync_file,
367 unsigned long arg)
368{
369 struct sync_set_deadline ts;
370
371 if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
372 return -EFAULT;
373
374 if (ts.pad)
375 return -EINVAL;
376
377 dma_fence_set_deadline(sync_file->fence, ns_to_ktime(ts.deadline_ns));
378
379 return 0;
380}
381
382static long sync_file_ioctl(struct file *file, unsigned int cmd,
383 unsigned long arg)
384{
385 struct sync_file *sync_file = file->private_data;
386
387 switch (cmd) {
388 case SYNC_IOC_MERGE:
389 return sync_file_ioctl_merge(sync_file, arg);
390
391 case SYNC_IOC_FILE_INFO:
392 return sync_file_ioctl_fence_info(sync_file, arg);
393
394 case SYNC_IOC_SET_DEADLINE:
395 return sync_file_ioctl_set_deadline(sync_file, arg);
396
397 default:
398 return -ENOTTY;
399 }
400}
401
402static const struct file_operations sync_file_fops = {
403 .release = sync_file_release,
404 .poll = sync_file_poll,
405 .unlocked_ioctl = sync_file_ioctl,
406 .compat_ioctl = compat_ptr_ioctl,
407};