1 /* 2 * drivers/dma-buf/sync_file.c 3 * 4 * Copyright (C) 2012 Google, Inc. 5 * 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. 9 * 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. 14 * 15 */ 16 17 #include <linux/export.h> 18 #include <linux/file.h> 19 #include <linux/fs.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> 28 29 static const struct file_operations sync_file_fops; 30 31 static struct sync_file *sync_file_alloc(void) 32 { 33 struct sync_file *sync_file; 34 35 sync_file = kzalloc(sizeof(*sync_file), GFP_KERNEL); 36 if (!sync_file) 37 return NULL; 38 39 sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops, 40 sync_file, 0); 41 if (IS_ERR(sync_file->file)) 42 goto err; 43 44 init_waitqueue_head(&sync_file->wq); 45 46 INIT_LIST_HEAD(&sync_file->cb.node); 47 48 return sync_file; 49 50 err: 51 kfree(sync_file); 52 return NULL; 53 } 54 55 static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb) 56 { 57 struct sync_file *sync_file; 58 59 sync_file = container_of(cb, struct sync_file, cb); 60 61 wake_up_all(&sync_file->wq); 62 } 63 64 /** 65 * sync_file_create() - creates a sync file 66 * @fence: fence to add to the sync_fence 67 * 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. 72 */ 73 struct sync_file *sync_file_create(struct dma_fence *fence) 74 { 75 struct sync_file *sync_file; 76 77 sync_file = sync_file_alloc(); 78 if (!sync_file) 79 return NULL; 80 81 sync_file->fence = dma_fence_get(fence); 82 83 return sync_file; 84 } 85 EXPORT_SYMBOL(sync_file_create); 86 87 static struct sync_file *sync_file_fdget(int fd) 88 { 89 struct file *file = fget(fd); 90 91 if (!file) 92 return NULL; 93 94 if (file->f_op != &sync_file_fops) 95 goto err; 96 97 return file->private_data; 98 99 err: 100 fput(file); 101 return NULL; 102 } 103 104 /** 105 * sync_file_get_fence - get the fence related to the sync_file fd 106 * @fd: sync_file fd to get the fence from 107 * 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. 110 */ 111 struct dma_fence *sync_file_get_fence(int fd) 112 { 113 struct sync_file *sync_file; 114 struct dma_fence *fence; 115 116 sync_file = sync_file_fdget(fd); 117 if (!sync_file) 118 return NULL; 119 120 fence = dma_fence_get(sync_file->fence); 121 fput(sync_file->file); 122 123 return fence; 124 } 125 EXPORT_SYMBOL(sync_file_get_fence); 126 127 /** 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. 132 * 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(). 137 * 138 * Returns: a string representing the name. 139 */ 140 char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len) 141 { 142 if (sync_file->user_name[0]) { 143 strlcpy(buf, sync_file->user_name, len); 144 } else { 145 struct dma_fence *fence = sync_file->fence; 146 147 snprintf(buf, len, "%s-%s%llu-%lld", 148 fence->ops->get_driver_name(fence), 149 fence->ops->get_timeline_name(fence), 150 fence->context, 151 fence->seqno); 152 } 153 154 return buf; 155 } 156 157 static int sync_file_set_fence(struct sync_file *sync_file, 158 struct dma_fence **fences, int num_fences) 159 { 160 struct dma_fence_array *array; 161 162 /* 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. 167 */ 168 if (num_fences == 1) { 169 sync_file->fence = fences[0]; 170 kfree(fences); 171 } else { 172 array = dma_fence_array_create(num_fences, fences, 173 dma_fence_context_alloc(1), 174 1, false); 175 if (!array) 176 return -ENOMEM; 177 178 sync_file->fence = &array->base; 179 } 180 181 return 0; 182 } 183 184 static struct dma_fence **get_fences(struct sync_file *sync_file, 185 int *num_fences) 186 { 187 if (dma_fence_is_array(sync_file->fence)) { 188 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence); 189 190 *num_fences = array->num_fences; 191 return array->fences; 192 } 193 194 *num_fences = 1; 195 return &sync_file->fence; 196 } 197 198 static void add_fence(struct dma_fence **fences, 199 int *i, struct dma_fence *fence) 200 { 201 fences[*i] = fence; 202 203 if (!dma_fence_is_signaled(fence)) { 204 dma_fence_get(fence); 205 (*i)++; 206 } 207 } 208 209 /** 210 * sync_file_merge() - merge two sync_files 211 * @name: name of new fence 212 * @a: sync_file a 213 * @b: sync_file b 214 * 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. 218 */ 219 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, 220 struct sync_file *b) 221 { 222 struct sync_file *sync_file; 223 struct dma_fence **fences, **nfences, **a_fences, **b_fences; 224 int i, i_a, i_b, num_fences, a_num_fences, b_num_fences; 225 226 sync_file = sync_file_alloc(); 227 if (!sync_file) 228 return NULL; 229 230 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) 233 return NULL; 234 235 num_fences = a_num_fences + b_num_fences; 236 237 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); 238 if (!fences) 239 goto err; 240 241 /* 242 * Assume sync_file a and b are both ordered and have no 243 * duplicates with the same context. 244 * 245 * If a sync_file can only be created with sync_file_merge 246 * and sync_file_create, this is a reasonable assumption. 247 */ 248 for (i = 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]; 251 252 if (pt_a->context < pt_b->context) { 253 add_fence(fences, &i, pt_a); 254 255 i_a++; 256 } else if (pt_a->context > pt_b->context) { 257 add_fence(fences, &i, pt_b); 258 259 i_b++; 260 } else { 261 if (__dma_fence_is_later(pt_a->seqno, pt_b->seqno, 262 pt_a->ops)) 263 add_fence(fences, &i, pt_a); 264 else 265 add_fence(fences, &i, pt_b); 266 267 i_a++; 268 i_b++; 269 } 270 } 271 272 for (; i_a < a_num_fences; i_a++) 273 add_fence(fences, &i, a_fences[i_a]); 274 275 for (; i_b < b_num_fences; i_b++) 276 add_fence(fences, &i, b_fences[i_b]); 277 278 if (i == 0) 279 fences[i++] = dma_fence_get(a_fences[0]); 280 281 if (num_fences > i) { 282 nfences = krealloc(fences, i * sizeof(*fences), 283 GFP_KERNEL); 284 if (!nfences) 285 goto err; 286 287 fences = nfences; 288 } 289 290 if (sync_file_set_fence(sync_file, fences, i) < 0) { 291 kfree(fences); 292 goto err; 293 } 294 295 strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name)); 296 return sync_file; 297 298 err: 299 fput(sync_file->file); 300 return NULL; 301 302 } 303 304 static int sync_file_release(struct inode *inode, struct file *file) 305 { 306 struct sync_file *sync_file = file->private_data; 307 308 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); 311 kfree(sync_file); 312 313 return 0; 314 } 315 316 static __poll_t sync_file_poll(struct file *file, poll_table *wait) 317 { 318 struct sync_file *sync_file = file->private_data; 319 320 poll_wait(file, &sync_file->wq, wait); 321 322 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); 327 } 328 329 return dma_fence_is_signaled(sync_file->fence) ? EPOLLIN : 0; 330 } 331 332 static long sync_file_ioctl_merge(struct sync_file *sync_file, 333 unsigned long arg) 334 { 335 int fd = get_unused_fd_flags(O_CLOEXEC); 336 int err; 337 struct sync_file *fence2, *fence3; 338 struct sync_merge_data data; 339 340 if (fd < 0) 341 return fd; 342 343 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { 344 err = -EFAULT; 345 goto err_put_fd; 346 } 347 348 if (data.flags || data.pad) { 349 err = -EINVAL; 350 goto err_put_fd; 351 } 352 353 fence2 = sync_file_fdget(data.fd2); 354 if (!fence2) { 355 err = -ENOENT; 356 goto err_put_fd; 357 } 358 359 data.name[sizeof(data.name) - 1] = '\0'; 360 fence3 = sync_file_merge(data.name, sync_file, fence2); 361 if (!fence3) { 362 err = -ENOMEM; 363 goto err_put_fence2; 364 } 365 366 data.fence = fd; 367 if (copy_to_user((void __user *)arg, &data, sizeof(data))) { 368 err = -EFAULT; 369 goto err_put_fence3; 370 } 371 372 fd_install(fd, fence3->file); 373 fput(fence2->file); 374 return 0; 375 376 err_put_fence3: 377 fput(fence3->file); 378 379 err_put_fence2: 380 fput(fence2->file); 381 382 err_put_fd: 383 put_unused_fd(fd); 384 return err; 385 } 386 387 static int sync_fill_fence_info(struct dma_fence *fence, 388 struct sync_fence_info *info) 389 { 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)); 394 395 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)) 398 cpu_relax(); 399 info->timestamp_ns = 400 test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ? 401 ktime_to_ns(fence->timestamp) : 402 ktime_set(0, 0); 403 404 return info->status; 405 } 406 407 static long sync_file_ioctl_fence_info(struct sync_file *sync_file, 408 unsigned long arg) 409 { 410 struct sync_file_info info; 411 struct sync_fence_info *fence_info = NULL; 412 struct dma_fence **fences; 413 __u32 size; 414 int num_fences, ret, i; 415 416 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 417 return -EFAULT; 418 419 if (info.flags || info.pad) 420 return -EINVAL; 421 422 fences = get_fences(sync_file, &num_fences); 423 424 /* 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 428 * info->num_fences. 429 */ 430 if (!info.num_fences) { 431 info.status = dma_fence_is_signaled(sync_file->fence); 432 goto no_fences; 433 } else { 434 info.status = 1; 435 } 436 437 if (info.num_fences < num_fences) 438 return -EINVAL; 439 440 size = num_fences * sizeof(*fence_info); 441 fence_info = kzalloc(size, GFP_KERNEL); 442 if (!fence_info) 443 return -ENOMEM; 444 445 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; 448 } 449 450 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, 451 size)) { 452 ret = -EFAULT; 453 goto out; 454 } 455 456 no_fences: 457 sync_file_get_name(sync_file, info.name, sizeof(info.name)); 458 info.num_fences = num_fences; 459 460 if (copy_to_user((void __user *)arg, &info, sizeof(info))) 461 ret = -EFAULT; 462 else 463 ret = 0; 464 465 out: 466 kfree(fence_info); 467 468 return ret; 469 } 470 471 static long sync_file_ioctl(struct file *file, unsigned int cmd, 472 unsigned long arg) 473 { 474 struct sync_file *sync_file = file->private_data; 475 476 switch (cmd) { 477 case SYNC_IOC_MERGE: 478 return sync_file_ioctl_merge(sync_file, arg); 479 480 case SYNC_IOC_FILE_INFO: 481 return sync_file_ioctl_fence_info(sync_file, arg); 482 483 default: 484 return -ENOTTY; 485 } 486 } 487 488 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, 493 }; 494