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 kref_init(&sync_file->kref);
46 init_waitqueue_head(&sync_file->wq);
48 INIT_LIST_HEAD(&sync_file->cb.node);
57 static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb)
59 struct sync_file *sync_file;
61 sync_file = container_of(cb, struct sync_file, cb);
63 wake_up_all(&sync_file->wq);
67 * sync_file_create() - creates a sync file
68 * @fence: fence to add to the sync_fence
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.
74 struct sync_file *sync_file_create(struct dma_fence *fence)
76 struct sync_file *sync_file;
78 sync_file = sync_file_alloc();
82 sync_file->fence = dma_fence_get(fence);
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,
91 EXPORT_SYMBOL(sync_file_create);
94 * sync_file_fdget() - get a sync_file from an fd
95 * @fd: fd referencing a fence
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.
100 static struct sync_file *sync_file_fdget(int fd)
102 struct file *file = fget(fd);
107 if (file->f_op != &sync_file_fops)
110 return file->private_data;
118 * sync_file_get_fence - get the fence related to the sync_file fd
119 * @fd: sync_file fd to get the fence from
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.
124 struct dma_fence *sync_file_get_fence(int fd)
126 struct sync_file *sync_file;
127 struct dma_fence *fence;
129 sync_file = sync_file_fdget(fd);
133 fence = dma_fence_get(sync_file->fence);
134 fput(sync_file->file);
138 EXPORT_SYMBOL(sync_file_get_fence);
140 static int sync_file_set_fence(struct sync_file *sync_file,
141 struct dma_fence **fences, int num_fences)
143 struct dma_fence_array *array;
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.
151 if (num_fences == 1) {
152 sync_file->fence = fences[0];
155 array = dma_fence_array_create(num_fences, fences,
156 dma_fence_context_alloc(1),
161 sync_file->fence = &array->base;
167 static struct dma_fence **get_fences(struct sync_file *sync_file,
170 if (dma_fence_is_array(sync_file->fence)) {
171 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
173 *num_fences = array->num_fences;
174 return array->fences;
178 return &sync_file->fence;
181 static void add_fence(struct dma_fence **fences,
182 int *i, struct dma_fence *fence)
186 if (!dma_fence_is_signaled(fence)) {
187 dma_fence_get(fence);
193 * sync_file_merge() - merge two sync_files
194 * @name: name of new fence
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.
202 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
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;
209 sync_file = sync_file_alloc();
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)
218 num_fences = a_num_fences + b_num_fences;
220 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
225 * Assume sync_file a and b are both ordered and have no
226 * duplicates with the same context.
228 * If a sync_file can only be created with sync_file_merge
229 * and sync_file_create, this is a reasonable assumption.
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];
235 if (pt_a->context < pt_b->context) {
236 add_fence(fences, &i, pt_a);
239 } else if (pt_a->context > pt_b->context) {
240 add_fence(fences, &i, pt_b);
244 if (pt_a->seqno - pt_b->seqno <= INT_MAX)
245 add_fence(fences, &i, pt_a);
247 add_fence(fences, &i, pt_b);
254 for (; i_a < a_num_fences; i_a++)
255 add_fence(fences, &i, a_fences[i_a]);
257 for (; i_b < b_num_fences; i_b++)
258 add_fence(fences, &i, b_fences[i_b]);
261 fences[i++] = dma_fence_get(a_fences[0]);
263 if (num_fences > i) {
264 nfences = krealloc(fences, i * sizeof(*fences),
272 if (sync_file_set_fence(sync_file, fences, i) < 0) {
277 strlcpy(sync_file->name, name, sizeof(sync_file->name));
281 fput(sync_file->file);
286 static void sync_file_free(struct kref *kref)
288 struct sync_file *sync_file = container_of(kref, struct sync_file,
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);
297 static int sync_file_release(struct inode *inode, struct file *file)
299 struct sync_file *sync_file = file->private_data;
301 kref_put(&sync_file->kref, sync_file_free);
305 static unsigned int sync_file_poll(struct file *file, poll_table *wait)
307 struct sync_file *sync_file = file->private_data;
309 poll_wait(file, &sync_file->wq, wait);
311 if (!poll_does_not_wait(wait) &&
312 !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
313 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb,
314 fence_check_cb_func) < 0)
315 wake_up_all(&sync_file->wq);
318 return dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0;
321 static long sync_file_ioctl_merge(struct sync_file *sync_file,
324 int fd = get_unused_fd_flags(O_CLOEXEC);
326 struct sync_file *fence2, *fence3;
327 struct sync_merge_data data;
332 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
337 if (data.flags || data.pad) {
342 fence2 = sync_file_fdget(data.fd2);
348 data.name[sizeof(data.name) - 1] = '\0';
349 fence3 = sync_file_merge(data.name, sync_file, fence2);
356 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
361 fd_install(fd, fence3->file);
376 static void sync_fill_fence_info(struct dma_fence *fence,
377 struct sync_fence_info *info)
379 strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
380 sizeof(info->obj_name));
381 strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
382 sizeof(info->driver_name));
383 if (dma_fence_is_signaled(fence))
384 info->status = fence->status >= 0 ? 1 : fence->status;
387 info->timestamp_ns = ktime_to_ns(fence->timestamp);
390 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
393 struct sync_file_info info;
394 struct sync_fence_info *fence_info = NULL;
395 struct dma_fence **fences;
397 int num_fences, ret, i;
399 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
402 if (info.flags || info.pad)
405 fences = get_fences(sync_file, &num_fences);
408 * Passing num_fences = 0 means that userspace doesn't want to
409 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
410 * sync_fence_info and return the actual number of fences on
413 if (!info.num_fences)
416 if (info.num_fences < num_fences)
419 size = num_fences * sizeof(*fence_info);
420 fence_info = kzalloc(size, GFP_KERNEL);
424 for (i = 0; i < num_fences; i++)
425 sync_fill_fence_info(fences[i], &fence_info[i]);
427 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
434 strlcpy(info.name, sync_file->name, sizeof(info.name));
435 info.status = dma_fence_is_signaled(sync_file->fence);
436 info.num_fences = num_fences;
438 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
449 static long sync_file_ioctl(struct file *file, unsigned int cmd,
452 struct sync_file *sync_file = file->private_data;
456 return sync_file_ioctl_merge(sync_file, arg);
458 case SYNC_IOC_FILE_INFO:
459 return sync_file_ioctl_fence_info(sync_file, arg);
466 static const struct file_operations sync_file_fops = {
467 .release = sync_file_release,
468 .poll = sync_file_poll,
469 .unlocked_ioctl = sync_file_ioctl,
470 .compat_ioctl = sync_file_ioctl,