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 fence *f, struct 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 fence *fence)
76 struct sync_file *sync_file;
78 sync_file = sync_file_alloc();
82 sync_file->fence = 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 fence *sync_file_get_fence(int fd)
126 struct sync_file *sync_file;
129 sync_file = sync_file_fdget(fd);
133 fence = 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 fence **fences, int num_fences)
143 struct 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 fence_array creation.
151 if (num_fences == 1) {
152 sync_file->fence = fences[0];
155 array = fence_array_create(num_fences, fences,
156 fence_context_alloc(1), 1, false);
160 sync_file->fence = &array->base;
166 static struct fence **get_fences(struct sync_file *sync_file, int *num_fences)
168 if (fence_is_array(sync_file->fence)) {
169 struct fence_array *array = to_fence_array(sync_file->fence);
171 *num_fences = array->num_fences;
172 return array->fences;
176 return &sync_file->fence;
179 static void add_fence(struct fence **fences, int *i, struct fence *fence)
183 if (!fence_is_signaled(fence)) {
190 * sync_file_merge() - merge two sync_files
191 * @name: name of new fence
195 * Creates a new sync_file which contains copies of all the fences in both
196 * @a and @b. @a and @b remain valid, independent sync_file. Returns the
197 * new merged sync_file or NULL in case of error.
199 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
202 struct sync_file *sync_file;
203 struct fence **fences, **nfences, **a_fences, **b_fences;
204 int i, i_a, i_b, num_fences, a_num_fences, b_num_fences;
206 sync_file = sync_file_alloc();
210 a_fences = get_fences(a, &a_num_fences);
211 b_fences = get_fences(b, &b_num_fences);
212 if (a_num_fences > INT_MAX - b_num_fences)
215 num_fences = a_num_fences + b_num_fences;
217 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
222 * Assume sync_file a and b are both ordered and have no
223 * duplicates with the same context.
225 * If a sync_file can only be created with sync_file_merge
226 * and sync_file_create, this is a reasonable assumption.
228 for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
229 struct fence *pt_a = a_fences[i_a];
230 struct fence *pt_b = b_fences[i_b];
232 if (pt_a->context < pt_b->context) {
233 add_fence(fences, &i, pt_a);
236 } else if (pt_a->context > pt_b->context) {
237 add_fence(fences, &i, pt_b);
241 if (pt_a->seqno - pt_b->seqno <= INT_MAX)
242 add_fence(fences, &i, pt_a);
244 add_fence(fences, &i, pt_b);
251 for (; i_a < a_num_fences; i_a++)
252 add_fence(fences, &i, a_fences[i_a]);
254 for (; i_b < b_num_fences; i_b++)
255 add_fence(fences, &i, b_fences[i_b]);
258 fences[i++] = fence_get(a_fences[0]);
260 if (num_fences > i) {
261 nfences = krealloc(fences, i * sizeof(*fences),
269 if (sync_file_set_fence(sync_file, fences, i) < 0) {
274 strlcpy(sync_file->name, name, sizeof(sync_file->name));
278 fput(sync_file->file);
283 static void sync_file_free(struct kref *kref)
285 struct sync_file *sync_file = container_of(kref, struct sync_file,
288 if (test_bit(POLL_ENABLED, &sync_file->fence->flags))
289 fence_remove_callback(sync_file->fence, &sync_file->cb);
290 fence_put(sync_file->fence);
294 static int sync_file_release(struct inode *inode, struct file *file)
296 struct sync_file *sync_file = file->private_data;
298 kref_put(&sync_file->kref, sync_file_free);
302 static unsigned int sync_file_poll(struct file *file, poll_table *wait)
304 struct sync_file *sync_file = file->private_data;
306 poll_wait(file, &sync_file->wq, wait);
308 if (!poll_does_not_wait(wait) &&
309 !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
310 if (fence_add_callback(sync_file->fence, &sync_file->cb,
311 fence_check_cb_func) < 0)
312 wake_up_all(&sync_file->wq);
315 return fence_is_signaled(sync_file->fence) ? POLLIN : 0;
318 static long sync_file_ioctl_merge(struct sync_file *sync_file,
321 int fd = get_unused_fd_flags(O_CLOEXEC);
323 struct sync_file *fence2, *fence3;
324 struct sync_merge_data data;
329 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
334 if (data.flags || data.pad) {
339 fence2 = sync_file_fdget(data.fd2);
345 data.name[sizeof(data.name) - 1] = '\0';
346 fence3 = sync_file_merge(data.name, sync_file, fence2);
353 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
358 fd_install(fd, fence3->file);
373 static void sync_fill_fence_info(struct fence *fence,
374 struct sync_fence_info *info)
376 strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
377 sizeof(info->obj_name));
378 strlcpy(info->driver_name, fence->ops->get_driver_name(fence),
379 sizeof(info->driver_name));
380 if (fence_is_signaled(fence))
381 info->status = fence->status >= 0 ? 1 : fence->status;
384 info->timestamp_ns = ktime_to_ns(fence->timestamp);
387 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
390 struct sync_file_info info;
391 struct sync_fence_info *fence_info = NULL;
392 struct fence **fences;
394 int num_fences, ret, i;
396 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
399 if (info.flags || info.pad)
402 fences = get_fences(sync_file, &num_fences);
405 * Passing num_fences = 0 means that userspace doesn't want to
406 * retrieve any sync_fence_info. If num_fences = 0 we skip filling
407 * sync_fence_info and return the actual number of fences on
410 if (!info.num_fences)
413 if (info.num_fences < num_fences)
416 size = num_fences * sizeof(*fence_info);
417 fence_info = kzalloc(size, GFP_KERNEL);
421 for (i = 0; i < num_fences; i++)
422 sync_fill_fence_info(fences[i], &fence_info[i]);
424 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
431 strlcpy(info.name, sync_file->name, sizeof(info.name));
432 info.status = fence_is_signaled(sync_file->fence);
433 info.num_fences = num_fences;
435 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
446 static long sync_file_ioctl(struct file *file, unsigned int cmd,
449 struct sync_file *sync_file = file->private_data;
453 return sync_file_ioctl_merge(sync_file, arg);
455 case SYNC_IOC_FILE_INFO:
456 return sync_file_ioctl_fence_info(sync_file, arg);
463 static const struct file_operations sync_file_fops = {
464 .release = sync_file_release,
465 .poll = sync_file_poll,
466 .unlocked_ioctl = sync_file_ioctl,
467 .compat_ioctl = sync_file_ioctl,