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 | |
21 | static const struct file_operations sync_file_fops; |
22 | |
23 | static struct sync_file *sync_file_alloc(void) |
24 | { |
25 | struct sync_file *sync_file; |
26 | |
27 | sync_file = kzalloc(size: sizeof(*sync_file), GFP_KERNEL); |
28 | if (!sync_file) |
29 | return NULL; |
30 | |
31 | sync_file->file = anon_inode_getfile(name: "sync_file" , fops: &sync_file_fops, |
32 | priv: sync_file, flags: 0); |
33 | if (IS_ERR(ptr: sync_file->file)) |
34 | goto err; |
35 | |
36 | init_waitqueue_head(&sync_file->wq); |
37 | |
38 | INIT_LIST_HEAD(list: &sync_file->cb.node); |
39 | |
40 | return sync_file; |
41 | |
42 | err: |
43 | kfree(objp: sync_file); |
44 | return NULL; |
45 | } |
46 | |
47 | static 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 | */ |
65 | struct 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 | } |
77 | EXPORT_SYMBOL(sync_file_create); |
78 | |
79 | static 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 | |
91 | err: |
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 | */ |
103 | struct 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(fence: sync_file->fence); |
113 | fput(sync_file->file); |
114 | |
115 | return fence; |
116 | } |
117 | EXPORT_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 | */ |
132 | char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len) |
133 | { |
134 | if (sync_file->user_name[0]) { |
135 | strscpy(p: buf, q: sync_file->user_name, size: len); |
136 | } else { |
137 | struct dma_fence *fence = sync_file->fence; |
138 | |
139 | snprintf(buf, size: len, fmt: "%s-%s%llu-%lld" , |
140 | fence->ops->get_driver_name(fence), |
141 | fence->ops->get_timeline_name(fence), |
142 | fence->context, |
143 | fence->seqno); |
144 | } |
145 | |
146 | return buf; |
147 | } |
148 | |
149 | /** |
150 | * sync_file_merge() - merge two sync_files |
151 | * @name: name of new fence |
152 | * @a: sync_file a |
153 | * @b: sync_file b |
154 | * |
155 | * Creates a new sync_file which contains copies of all the fences in both |
156 | * @a and @b. @a and @b remain valid, independent sync_file. Returns the |
157 | * new merged sync_file or NULL in case of error. |
158 | */ |
159 | static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, |
160 | struct sync_file *b) |
161 | { |
162 | struct sync_file *sync_file; |
163 | struct dma_fence *fence; |
164 | |
165 | sync_file = sync_file_alloc(); |
166 | if (!sync_file) |
167 | return NULL; |
168 | |
169 | fence = dma_fence_unwrap_merge(a->fence, b->fence); |
170 | if (!fence) { |
171 | fput(sync_file->file); |
172 | return NULL; |
173 | } |
174 | sync_file->fence = fence; |
175 | strscpy(p: sync_file->user_name, q: name, size: sizeof(sync_file->user_name)); |
176 | return sync_file; |
177 | } |
178 | |
179 | static int sync_file_release(struct inode *inode, struct file *file) |
180 | { |
181 | struct sync_file *sync_file = file->private_data; |
182 | |
183 | if (test_bit(POLL_ENABLED, &sync_file->flags)) |
184 | dma_fence_remove_callback(fence: sync_file->fence, cb: &sync_file->cb); |
185 | dma_fence_put(fence: sync_file->fence); |
186 | kfree(objp: sync_file); |
187 | |
188 | return 0; |
189 | } |
190 | |
191 | static __poll_t sync_file_poll(struct file *file, poll_table *wait) |
192 | { |
193 | struct sync_file *sync_file = file->private_data; |
194 | |
195 | poll_wait(filp: file, wait_address: &sync_file->wq, p: wait); |
196 | |
197 | if (list_empty(head: &sync_file->cb.node) && |
198 | !test_and_set_bit(POLL_ENABLED, addr: &sync_file->flags)) { |
199 | if (dma_fence_add_callback(fence: sync_file->fence, cb: &sync_file->cb, |
200 | func: fence_check_cb_func) < 0) |
201 | wake_up_all(&sync_file->wq); |
202 | } |
203 | |
204 | return dma_fence_is_signaled(fence: sync_file->fence) ? EPOLLIN : 0; |
205 | } |
206 | |
207 | static long sync_file_ioctl_merge(struct sync_file *sync_file, |
208 | unsigned long arg) |
209 | { |
210 | int fd = get_unused_fd_flags(O_CLOEXEC); |
211 | int err; |
212 | struct sync_file *fence2, *fence3; |
213 | struct sync_merge_data data; |
214 | |
215 | if (fd < 0) |
216 | return fd; |
217 | |
218 | if (copy_from_user(to: &data, from: (void __user *)arg, n: sizeof(data))) { |
219 | err = -EFAULT; |
220 | goto err_put_fd; |
221 | } |
222 | |
223 | if (data.flags || data.pad) { |
224 | err = -EINVAL; |
225 | goto err_put_fd; |
226 | } |
227 | |
228 | fence2 = sync_file_fdget(fd: data.fd2); |
229 | if (!fence2) { |
230 | err = -ENOENT; |
231 | goto err_put_fd; |
232 | } |
233 | |
234 | data.name[sizeof(data.name) - 1] = '\0'; |
235 | fence3 = sync_file_merge(name: data.name, a: sync_file, b: fence2); |
236 | if (!fence3) { |
237 | err = -ENOMEM; |
238 | goto err_put_fence2; |
239 | } |
240 | |
241 | data.fence = fd; |
242 | if (copy_to_user(to: (void __user *)arg, from: &data, n: sizeof(data))) { |
243 | err = -EFAULT; |
244 | goto err_put_fence3; |
245 | } |
246 | |
247 | fd_install(fd, file: fence3->file); |
248 | fput(fence2->file); |
249 | return 0; |
250 | |
251 | err_put_fence3: |
252 | fput(fence3->file); |
253 | |
254 | err_put_fence2: |
255 | fput(fence2->file); |
256 | |
257 | err_put_fd: |
258 | put_unused_fd(fd); |
259 | return err; |
260 | } |
261 | |
262 | static int sync_fill_fence_info(struct dma_fence *fence, |
263 | struct sync_fence_info *info) |
264 | { |
265 | strscpy(p: info->obj_name, q: fence->ops->get_timeline_name(fence), |
266 | size: sizeof(info->obj_name)); |
267 | strscpy(p: info->driver_name, q: fence->ops->get_driver_name(fence), |
268 | size: sizeof(info->driver_name)); |
269 | |
270 | info->status = dma_fence_get_status(fence); |
271 | info->timestamp_ns = |
272 | dma_fence_is_signaled(fence) ? |
273 | ktime_to_ns(kt: dma_fence_timestamp(fence)) : |
274 | ktime_set(secs: 0, nsecs: 0); |
275 | |
276 | return info->status; |
277 | } |
278 | |
279 | static long sync_file_ioctl_fence_info(struct sync_file *sync_file, |
280 | unsigned long arg) |
281 | { |
282 | struct sync_fence_info *fence_info = NULL; |
283 | struct dma_fence_unwrap iter; |
284 | struct sync_file_info info; |
285 | unsigned int num_fences; |
286 | struct dma_fence *fence; |
287 | int ret; |
288 | __u32 size; |
289 | |
290 | if (copy_from_user(to: &info, from: (void __user *)arg, n: sizeof(info))) |
291 | return -EFAULT; |
292 | |
293 | if (info.flags || info.pad) |
294 | return -EINVAL; |
295 | |
296 | num_fences = 0; |
297 | dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) |
298 | ++num_fences; |
299 | |
300 | /* |
301 | * Passing num_fences = 0 means that userspace doesn't want to |
302 | * retrieve any sync_fence_info. If num_fences = 0 we skip filling |
303 | * sync_fence_info and return the actual number of fences on |
304 | * info->num_fences. |
305 | */ |
306 | if (!info.num_fences) { |
307 | info.status = dma_fence_get_status(fence: sync_file->fence); |
308 | goto no_fences; |
309 | } else { |
310 | info.status = 1; |
311 | } |
312 | |
313 | if (info.num_fences < num_fences) |
314 | return -EINVAL; |
315 | |
316 | size = num_fences * sizeof(*fence_info); |
317 | fence_info = kzalloc(size, GFP_KERNEL); |
318 | if (!fence_info) |
319 | return -ENOMEM; |
320 | |
321 | num_fences = 0; |
322 | dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) { |
323 | int status; |
324 | |
325 | status = sync_fill_fence_info(fence, info: &fence_info[num_fences++]); |
326 | info.status = info.status <= 0 ? info.status : status; |
327 | } |
328 | |
329 | if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), from: fence_info, |
330 | n: size)) { |
331 | ret = -EFAULT; |
332 | goto out; |
333 | } |
334 | |
335 | no_fences: |
336 | sync_file_get_name(sync_file, buf: info.name, len: sizeof(info.name)); |
337 | info.num_fences = num_fences; |
338 | |
339 | if (copy_to_user(to: (void __user *)arg, from: &info, n: sizeof(info))) |
340 | ret = -EFAULT; |
341 | else |
342 | ret = 0; |
343 | |
344 | out: |
345 | kfree(objp: fence_info); |
346 | |
347 | return ret; |
348 | } |
349 | |
350 | static long sync_file_ioctl(struct file *file, unsigned int cmd, |
351 | unsigned long arg) |
352 | { |
353 | struct sync_file *sync_file = file->private_data; |
354 | |
355 | switch (cmd) { |
356 | case SYNC_IOC_MERGE: |
357 | return sync_file_ioctl_merge(sync_file, arg); |
358 | |
359 | case SYNC_IOC_FILE_INFO: |
360 | return sync_file_ioctl_fence_info(sync_file, arg); |
361 | |
362 | default: |
363 | return -ENOTTY; |
364 | } |
365 | } |
366 | |
367 | static const struct file_operations sync_file_fops = { |
368 | .release = sync_file_release, |
369 | .poll = sync_file_poll, |
370 | .unlocked_ioctl = sync_file_ioctl, |
371 | .compat_ioctl = compat_ptr_ioctl, |
372 | }; |
373 | |