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 kref_init(&sync_file->kref); 45 46 init_waitqueue_head(&sync_file->wq); 47 48 INIT_LIST_HEAD(&sync_file->cb.node); 49 50 return sync_file; 51 52 err: 53 kfree(sync_file); 54 return NULL; 55 } 56 57 static void fence_check_cb_func(struct fence *f, struct fence_cb *cb) 58 { 59 struct sync_file *sync_file; 60 61 sync_file = container_of(cb, struct sync_file, cb); 62 63 wake_up_all(&sync_file->wq); 64 } 65 66 /** 67 * sync_file_create() - creates a sync file 68 * @fence: fence to add to the sync_fence 69 * 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. 73 */ 74 struct sync_file *sync_file_create(struct fence *fence) 75 { 76 struct sync_file *sync_file; 77 78 sync_file = sync_file_alloc(); 79 if (!sync_file) 80 return NULL; 81 82 sync_file->fence = fence; 83 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, 87 fence->seqno); 88 89 return sync_file; 90 } 91 EXPORT_SYMBOL(sync_file_create); 92 93 /** 94 * sync_file_fdget() - get a sync_file from an fd 95 * @fd: fd referencing a fence 96 * 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. 99 */ 100 static struct sync_file *sync_file_fdget(int fd) 101 { 102 struct file *file = fget(fd); 103 104 if (!file) 105 return NULL; 106 107 if (file->f_op != &sync_file_fops) 108 goto err; 109 110 return file->private_data; 111 112 err: 113 fput(file); 114 return NULL; 115 } 116 117 /** 118 * sync_file_get_fence - get the fence related to the sync_file fd 119 * @fd: sync_file fd to get the fence from 120 * 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. 123 */ 124 struct fence *sync_file_get_fence(int fd) 125 { 126 struct sync_file *sync_file; 127 struct fence *fence; 128 129 sync_file = sync_file_fdget(fd); 130 if (!sync_file) 131 return NULL; 132 133 fence = fence_get(sync_file->fence); 134 fput(sync_file->file); 135 136 return fence; 137 } 138 EXPORT_SYMBOL(sync_file_get_fence); 139 140 static int sync_file_set_fence(struct sync_file *sync_file, 141 struct fence **fences, int num_fences) 142 { 143 struct fence_array *array; 144 145 /* 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. 150 */ 151 if (num_fences == 1) { 152 sync_file->fence = fences[0]; 153 kfree(fences); 154 } else { 155 array = fence_array_create(num_fences, fences, 156 fence_context_alloc(1), 1, false); 157 if (!array) 158 return -ENOMEM; 159 160 sync_file->fence = &array->base; 161 } 162 163 return 0; 164 } 165 166 static struct fence **get_fences(struct sync_file *sync_file, int *num_fences) 167 { 168 if (fence_is_array(sync_file->fence)) { 169 struct fence_array *array = to_fence_array(sync_file->fence); 170 171 *num_fences = array->num_fences; 172 return array->fences; 173 } 174 175 *num_fences = 1; 176 return &sync_file->fence; 177 } 178 179 static void add_fence(struct fence **fences, int *i, struct fence *fence) 180 { 181 fences[*i] = fence; 182 183 if (!fence_is_signaled(fence)) { 184 fence_get(fence); 185 (*i)++; 186 } 187 } 188 189 /** 190 * sync_file_merge() - merge two sync_files 191 * @name: name of new fence 192 * @a: sync_file a 193 * @b: sync_file b 194 * 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. 198 */ 199 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, 200 struct sync_file *b) 201 { 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; 205 206 sync_file = sync_file_alloc(); 207 if (!sync_file) 208 return NULL; 209 210 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) 213 return NULL; 214 215 num_fences = a_num_fences + b_num_fences; 216 217 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); 218 if (!fences) 219 goto err; 220 221 /* 222 * Assume sync_file a and b are both ordered and have no 223 * duplicates with the same context. 224 * 225 * If a sync_file can only be created with sync_file_merge 226 * and sync_file_create, this is a reasonable assumption. 227 */ 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]; 231 232 if (pt_a->context < pt_b->context) { 233 add_fence(fences, &i, pt_a); 234 235 i_a++; 236 } else if (pt_a->context > pt_b->context) { 237 add_fence(fences, &i, pt_b); 238 239 i_b++; 240 } else { 241 if (pt_a->seqno - pt_b->seqno <= INT_MAX) 242 add_fence(fences, &i, pt_a); 243 else 244 add_fence(fences, &i, pt_b); 245 246 i_a++; 247 i_b++; 248 } 249 } 250 251 for (; i_a < a_num_fences; i_a++) 252 add_fence(fences, &i, a_fences[i_a]); 253 254 for (; i_b < b_num_fences; i_b++) 255 add_fence(fences, &i, b_fences[i_b]); 256 257 if (i == 0) 258 fences[i++] = fence_get(a_fences[0]); 259 260 if (num_fences > i) { 261 nfences = krealloc(fences, i * sizeof(*fences), 262 GFP_KERNEL); 263 if (!nfences) 264 goto err; 265 266 fences = nfences; 267 } 268 269 if (sync_file_set_fence(sync_file, fences, i) < 0) { 270 kfree(fences); 271 goto err; 272 } 273 274 strlcpy(sync_file->name, name, sizeof(sync_file->name)); 275 return sync_file; 276 277 err: 278 fput(sync_file->file); 279 return NULL; 280 281 } 282 283 static void sync_file_free(struct kref *kref) 284 { 285 struct sync_file *sync_file = container_of(kref, struct sync_file, 286 kref); 287 288 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); 291 kfree(sync_file); 292 } 293 294 static int sync_file_release(struct inode *inode, struct file *file) 295 { 296 struct sync_file *sync_file = file->private_data; 297 298 kref_put(&sync_file->kref, sync_file_free); 299 return 0; 300 } 301 302 static unsigned int sync_file_poll(struct file *file, poll_table *wait) 303 { 304 struct sync_file *sync_file = file->private_data; 305 306 poll_wait(file, &sync_file->wq, wait); 307 308 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); 313 } 314 315 return fence_is_signaled(sync_file->fence) ? POLLIN : 0; 316 } 317 318 static long sync_file_ioctl_merge(struct sync_file *sync_file, 319 unsigned long arg) 320 { 321 int fd = get_unused_fd_flags(O_CLOEXEC); 322 int err; 323 struct sync_file *fence2, *fence3; 324 struct sync_merge_data data; 325 326 if (fd < 0) 327 return fd; 328 329 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { 330 err = -EFAULT; 331 goto err_put_fd; 332 } 333 334 if (data.flags || data.pad) { 335 err = -EINVAL; 336 goto err_put_fd; 337 } 338 339 fence2 = sync_file_fdget(data.fd2); 340 if (!fence2) { 341 err = -ENOENT; 342 goto err_put_fd; 343 } 344 345 data.name[sizeof(data.name) - 1] = '\0'; 346 fence3 = sync_file_merge(data.name, sync_file, fence2); 347 if (!fence3) { 348 err = -ENOMEM; 349 goto err_put_fence2; 350 } 351 352 data.fence = fd; 353 if (copy_to_user((void __user *)arg, &data, sizeof(data))) { 354 err = -EFAULT; 355 goto err_put_fence3; 356 } 357 358 fd_install(fd, fence3->file); 359 fput(fence2->file); 360 return 0; 361 362 err_put_fence3: 363 fput(fence3->file); 364 365 err_put_fence2: 366 fput(fence2->file); 367 368 err_put_fd: 369 put_unused_fd(fd); 370 return err; 371 } 372 373 static void sync_fill_fence_info(struct fence *fence, 374 struct sync_fence_info *info) 375 { 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; 382 else 383 info->status = 0; 384 info->timestamp_ns = ktime_to_ns(fence->timestamp); 385 } 386 387 static long sync_file_ioctl_fence_info(struct sync_file *sync_file, 388 unsigned long arg) 389 { 390 struct sync_file_info info; 391 struct sync_fence_info *fence_info = NULL; 392 struct fence **fences; 393 __u32 size; 394 int num_fences, ret, i; 395 396 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 397 return -EFAULT; 398 399 if (info.flags || info.pad) 400 return -EINVAL; 401 402 fences = get_fences(sync_file, &num_fences); 403 404 /* 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 408 * info->num_fences. 409 */ 410 if (!info.num_fences) 411 goto no_fences; 412 413 if (info.num_fences < num_fences) 414 return -EINVAL; 415 416 size = num_fences * sizeof(*fence_info); 417 fence_info = kzalloc(size, GFP_KERNEL); 418 if (!fence_info) 419 return -ENOMEM; 420 421 for (i = 0; i < num_fences; i++) 422 sync_fill_fence_info(fences[i], &fence_info[i]); 423 424 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, 425 size)) { 426 ret = -EFAULT; 427 goto out; 428 } 429 430 no_fences: 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; 434 435 if (copy_to_user((void __user *)arg, &info, sizeof(info))) 436 ret = -EFAULT; 437 else 438 ret = 0; 439 440 out: 441 kfree(fence_info); 442 443 return ret; 444 } 445 446 static long sync_file_ioctl(struct file *file, unsigned int cmd, 447 unsigned long arg) 448 { 449 struct sync_file *sync_file = file->private_data; 450 451 switch (cmd) { 452 case SYNC_IOC_MERGE: 453 return sync_file_ioctl_merge(sync_file, arg); 454 455 case SYNC_IOC_FILE_INFO: 456 return sync_file_ioctl_fence_info(sync_file, arg); 457 458 default: 459 return -ENOTTY; 460 } 461 } 462 463 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, 468 }; 469 470