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(sizeof(*sync_file), GFP_KERNEL); 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 42 err: 43 kfree(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(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(buf, sync_file->user_name, len); 136 } else { 137 struct dma_fence *fence = sync_file->fence; 138 139 snprintf(buf, len, "%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(sync_file->user_name, name, 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(sync_file->fence, &sync_file->cb); 185 dma_fence_put(sync_file->fence); 186 kfree(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(file, &sync_file->wq, wait); 196 197 if (list_empty(&sync_file->cb.node) && 198 !test_and_set_bit(POLL_ENABLED, &sync_file->flags)) { 199 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb, 200 fence_check_cb_func) < 0) 201 wake_up_all(&sync_file->wq); 202 } 203 204 return dma_fence_is_signaled(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(&data, (void __user *)arg, 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(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(data.name, sync_file, fence2); 236 if (!fence3) { 237 err = -ENOMEM; 238 goto err_put_fence2; 239 } 240 241 data.fence = fd; 242 if (copy_to_user((void __user *)arg, &data, sizeof(data))) { 243 err = -EFAULT; 244 goto err_put_fence3; 245 } 246 247 fd_install(fd, 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(info->obj_name, fence->ops->get_timeline_name(fence), 266 sizeof(info->obj_name)); 267 strscpy(info->driver_name, fence->ops->get_driver_name(fence), 268 sizeof(info->driver_name)); 269 270 info->status = dma_fence_get_status(fence); 271 while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && 272 !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) 273 cpu_relax(); 274 info->timestamp_ns = 275 test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ? 276 ktime_to_ns(fence->timestamp) : 277 ktime_set(0, 0); 278 279 return info->status; 280 } 281 282 static long sync_file_ioctl_fence_info(struct sync_file *sync_file, 283 unsigned long arg) 284 { 285 struct sync_fence_info *fence_info = NULL; 286 struct dma_fence_unwrap iter; 287 struct sync_file_info info; 288 unsigned int num_fences; 289 struct dma_fence *fence; 290 int ret; 291 __u32 size; 292 293 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 294 return -EFAULT; 295 296 if (info.flags || info.pad) 297 return -EINVAL; 298 299 num_fences = 0; 300 dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) 301 ++num_fences; 302 303 /* 304 * Passing num_fences = 0 means that userspace doesn't want to 305 * retrieve any sync_fence_info. If num_fences = 0 we skip filling 306 * sync_fence_info and return the actual number of fences on 307 * info->num_fences. 308 */ 309 if (!info.num_fences) { 310 info.status = dma_fence_get_status(sync_file->fence); 311 goto no_fences; 312 } else { 313 info.status = 1; 314 } 315 316 if (info.num_fences < num_fences) 317 return -EINVAL; 318 319 size = num_fences * sizeof(*fence_info); 320 fence_info = kzalloc(size, GFP_KERNEL); 321 if (!fence_info) 322 return -ENOMEM; 323 324 num_fences = 0; 325 dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) { 326 int status; 327 328 status = sync_fill_fence_info(fence, &fence_info[num_fences++]); 329 info.status = info.status <= 0 ? info.status : status; 330 } 331 332 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, 333 size)) { 334 ret = -EFAULT; 335 goto out; 336 } 337 338 no_fences: 339 sync_file_get_name(sync_file, info.name, sizeof(info.name)); 340 info.num_fences = num_fences; 341 342 if (copy_to_user((void __user *)arg, &info, sizeof(info))) 343 ret = -EFAULT; 344 else 345 ret = 0; 346 347 out: 348 kfree(fence_info); 349 350 return ret; 351 } 352 353 static long sync_file_ioctl(struct file *file, unsigned int cmd, 354 unsigned long arg) 355 { 356 struct sync_file *sync_file = file->private_data; 357 358 switch (cmd) { 359 case SYNC_IOC_MERGE: 360 return sync_file_ioctl_merge(sync_file, arg); 361 362 case SYNC_IOC_FILE_INFO: 363 return sync_file_ioctl_fence_info(sync_file, arg); 364 365 default: 366 return -ENOTTY; 367 } 368 } 369 370 static const struct file_operations sync_file_fops = { 371 .release = sync_file_release, 372 .poll = sync_file_poll, 373 .unlocked_ioctl = sync_file_ioctl, 374 .compat_ioctl = compat_ptr_ioctl, 375 }; 376