2 * drivers/dma-buf/sync_file.c
4 * Copyright (C) 2012 Google, Inc.
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.
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.
17 #include <linux/export.h>
18 #include <linux/file.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>
29 static const struct file_operations sync_file_fops;
31 static struct sync_file *sync_file_alloc(void)
33 struct sync_file *sync_file;
35 sync_file = kzalloc(sizeof(*sync_file), GFP_KERNEL);
39 sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops,
41 if (IS_ERR(sync_file->file))
44 init_waitqueue_head(&sync_file->wq);
46 INIT_LIST_HEAD(&sync_file->cb.node);
55 static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb)
57 struct sync_file *sync_file;
59 sync_file = container_of(cb, struct sync_file, cb);
61 wake_up_all(&sync_file->wq);
65 * sync_file_create() - creates a sync file
66 * @fence: fence to add to the sync_fence
68 * Creates a sync_file containg @fence. This function acquires and additional
69 * reference of @fence for the newly-created &sync_file, if it succeeds. The
70 * sync_file can be released with fput(sync_file->file). Returns the
71 * sync_file or NULL in case of error.
73 struct sync_file *sync_file_create(struct dma_fence *fence)
75 struct sync_file *sync_file;
77 sync_file = sync_file_alloc();
81 sync_file->fence = dma_fence_get(fence);
85 EXPORT_SYMBOL(sync_file_create);
87 static struct sync_file *sync_file_fdget(int fd)
89 struct file *file = fget(fd);
94 if (file->f_op != &sync_file_fops)
97 return file->private_data;
105 * sync_file_get_fence - get the fence related to the sync_file fd
106 * @fd: sync_file fd to get the fence from
108 * Ensures @fd references a valid sync_file and returns a fence that
109 * represents all fence in the sync_file. On error NULL is returned.
111 struct dma_fence *sync_file_get_fence(int fd)
113 struct sync_file *sync_file;
114 struct dma_fence *fence;
116 sync_file = sync_file_fdget(fd);
120 fence = dma_fence_get(sync_file->fence);
121 fput(sync_file->file);
125 EXPORT_SYMBOL(sync_file_get_fence);
128 * sync_file_get_name - get the name of the sync_file
129 * @sync_file: sync_file to get the fence from
130 * @buf: destination buffer to copy sync_file name into
131 * @len: available size of destination buffer.
133 * Each sync_file may have a name assigned either by the user (when merging
134 * sync_files together) or created from the fence it contains. In the latter
135 * case construction of the name is deferred until use, and so requires
136 * sync_file_get_name().
138 * Returns: a string representing the name.
140 char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len)
142 if (sync_file->user_name[0]) {
143 strlcpy(buf, sync_file->user_name, len);
145 struct dma_fence *fence = sync_file->fence;
147 snprintf(buf, len, "%s-%s%llu-%d",
148 fence->ops->get_driver_name(fence),
149 fence->ops->get_timeline_name(fence),
157 static int sync_file_set_fence(struct sync_file *sync_file,
158 struct dma_fence **fences, int num_fences)
160 struct dma_fence_array *array;
163 * The reference for the fences in the new sync_file and held
164 * in add_fence() during the merge procedure, so for num_fences == 1
165 * we already own a new reference to the fence. For num_fence > 1
166 * we own the reference of the dma_fence_array creation.
168 if (num_fences == 1) {
169 sync_file->fence = fences[0];
172 array = dma_fence_array_create(num_fences, fences,
173 dma_fence_context_alloc(1),
178 sync_file->fence = &array->base;
184 static struct dma_fence **get_fences(struct sync_file *sync_file,
187 if (dma_fence_is_array(sync_file->fence)) {
188 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
190 *num_fences = array->num_fences;
191 return array->fences;
195 return &sync_file->fence;
198 static void add_fence(struct dma_fence **fences,
199 int *i, struct dma_fence *fence)
203 if (!dma_fence_is_signaled(fence)) {
204 dma_fence_get(fence);
210 * sync_file_merge() - merge two sync_files
211 * @name: name of new fence
215 * Creates a new sync_file which contains copies of all the fences in both
216 * @a and @b. @a and @b remain valid, independent sync_file. Returns the
217 * new merged sync_file or NULL in case of error.
219 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
222 struct sync_file *sync_file;
223 struct dma_fence **fences = NULL, **nfences, **a_fences, **b_fences;
224 int i = 0, i_a, i_b, num_fences, a_num_fences, b_num_fences;
226 sync_file = sync_file_alloc();
230 a_fences = get_fences(a, &a_num_fences);
231 b_fences = get_fences(b, &b_num_fences);
232 if (a_num_fences > INT_MAX - b_num_fences)
235 num_fences = a_num_fences + b_num_fences;
237 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
242 * Assume sync_file a and b are both ordered and have no
243 * duplicates with the same context.
245 * If a sync_file can only be created with sync_file_merge
246 * and sync_file_create, this is a reasonable assumption.
248 for (i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
249 struct dma_fence *pt_a = a_fences[i_a];
250 struct dma_fence *pt_b = b_fences[i_b];
252 if (pt_a->context < pt_b->context) {
253 add_fence(fences, &i, pt_a);
256 } else if (pt_a->context > pt_b->context) {
257 add_fence(fences, &i, pt_b);
261 if (pt_a->seqno - pt_b->seqno <= INT_MAX)
262 add_fence(fences, &i, pt_a);
264 add_fence(fences, &i, pt_b);
271 for (; i_a < a_num_fences; i_a++)
272 add_fence(fences, &i, a_fences[i_a]);
274 for (; i_b < b_num_fences; i_b++)
275 add_fence(fences, &i, b_fences[i_b]);
278 fences[i++] = dma_fence_get(a_fences[0]);
280 if (num_fences > i) {
281 nfences = krealloc(fences, i * sizeof(*fences),
289 if (sync_file_set_fence(sync_file, fences, i) < 0)
292 strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name));
297 dma_fence_put(fences[--i]);
299 fput(sync_file->file);
304 static int sync_file_release(struct inode *inode, struct file *file)
306 struct sync_file *sync_file = file->private_data;
308 if (test_bit(POLL_ENABLED, &sync_file->flags))
309 dma_fence_remove_callback(sync_file->fence, &sync_file->cb);
310 dma_fence_put(sync_file->fence);
316 static __poll_t sync_file_poll(struct file *file, poll_table *wait)
318 struct sync_file *sync_file = file->private_data;
320 poll_wait(file, &sync_file->wq, wait);
322 if (list_empty(&sync_file->cb.node) &&
323 !test_and_set_bit(POLL_ENABLED, &sync_file->flags)) {
324 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb,
325 fence_check_cb_func) < 0)
326 wake_up_all(&sync_file->wq);
329 return dma_fence_is_signaled(sync_file->fence) ? EPOLLIN : 0;
332 static long sync_file_ioctl_merge(struct sync_file *sync_file,
335 int fd = get_unused_fd_flags(O_CLOEXEC);
337 struct sync_file *fence2, *fence3;
338 struct sync_merge_data data;
343 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
348 if (data.flags || data.pad) {
353 fence2 = sync_file_fdget(data.fd2);
359 data.name[sizeof(data.name) - 1] = '\0';
360 fence3 = sync_file_merge(data.name, sync_file, fence2);
367 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
372 fd_install(fd, fence3->file);
387 static int sync_fill_fence_info(struct dma_fence *fence,
388 struct sync_fence_info *info)
390 strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
391 sizeof(info->obj_name));
392 strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
393 sizeof(info->driver_name));
395 info->status = dma_fence_get_status(fence);
396 while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) &&
397 !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags))
400 test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ?
401 ktime_to_ns(fence->timestamp) :
407 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
410 struct sync_file_info info;
411 struct sync_fence_info *fence_info = NULL;
412 struct dma_fence **fences;
414 int num_fences, ret, i;
416 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
419 if (info.flags || info.pad)
422 fences = get_fences(sync_file, &num_fences);
425 * Passing num_fences = 0 means that userspace doesn't want to
426 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
427 * sync_fence_info and return the actual number of fences on
430 if (!info.num_fences) {
431 info.status = dma_fence_is_signaled(sync_file->fence);
437 if (info.num_fences < num_fences)
440 size = num_fences * sizeof(*fence_info);
441 fence_info = kzalloc(size, GFP_KERNEL);
445 for (i = 0; i < num_fences; i++) {
446 int status = sync_fill_fence_info(fences[i], &fence_info[i]);
447 info.status = info.status <= 0 ? info.status : status;
450 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
457 sync_file_get_name(sync_file, info.name, sizeof(info.name));
458 info.num_fences = num_fences;
460 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
471 static long sync_file_ioctl(struct file *file, unsigned int cmd,
474 struct sync_file *sync_file = file->private_data;
478 return sync_file_ioctl_merge(sync_file, arg);
480 case SYNC_IOC_FILE_INFO:
481 return sync_file_ioctl_fence_info(sync_file, arg);
488 static const struct file_operations sync_file_fops = {
489 .release = sync_file_release,
490 .poll = sync_file_poll,
491 .unlocked_ioctl = sync_file_ioctl,
492 .compat_ioctl = sync_file_ioctl,