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 dma_fence *f, struct dma_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. This function acquires and additional 71 * reference of @fence for the newly-created &sync_file, if it succeeds. The 72 * sync_file can be released with fput(sync_file->file). Returns the 73 * sync_file or NULL in case of error. 74 */ 75 struct sync_file *sync_file_create(struct dma_fence *fence) 76 { 77 struct sync_file *sync_file; 78 79 sync_file = sync_file_alloc(); 80 if (!sync_file) 81 return NULL; 82 83 sync_file->fence = dma_fence_get(fence); 84 85 snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d", 86 fence->ops->get_driver_name(fence), 87 fence->ops->get_timeline_name(fence), fence->context, 88 fence->seqno); 89 90 return sync_file; 91 } 92 EXPORT_SYMBOL(sync_file_create); 93 94 static struct sync_file *sync_file_fdget(int fd) 95 { 96 struct file *file = fget(fd); 97 98 if (!file) 99 return NULL; 100 101 if (file->f_op != &sync_file_fops) 102 goto err; 103 104 return file->private_data; 105 106 err: 107 fput(file); 108 return NULL; 109 } 110 111 /** 112 * sync_file_get_fence - get the fence related to the sync_file fd 113 * @fd: sync_file fd to get the fence from 114 * 115 * Ensures @fd references a valid sync_file and returns a fence that 116 * represents all fence in the sync_file. On error NULL is returned. 117 */ 118 struct dma_fence *sync_file_get_fence(int fd) 119 { 120 struct sync_file *sync_file; 121 struct dma_fence *fence; 122 123 sync_file = sync_file_fdget(fd); 124 if (!sync_file) 125 return NULL; 126 127 fence = dma_fence_get(sync_file->fence); 128 fput(sync_file->file); 129 130 return fence; 131 } 132 EXPORT_SYMBOL(sync_file_get_fence); 133 134 static int sync_file_set_fence(struct sync_file *sync_file, 135 struct dma_fence **fences, int num_fences) 136 { 137 struct dma_fence_array *array; 138 139 /* 140 * The reference for the fences in the new sync_file and held 141 * in add_fence() during the merge procedure, so for num_fences == 1 142 * we already own a new reference to the fence. For num_fence > 1 143 * we own the reference of the dma_fence_array creation. 144 */ 145 if (num_fences == 1) { 146 sync_file->fence = fences[0]; 147 kfree(fences); 148 } else { 149 array = dma_fence_array_create(num_fences, fences, 150 dma_fence_context_alloc(1), 151 1, false); 152 if (!array) 153 return -ENOMEM; 154 155 sync_file->fence = &array->base; 156 } 157 158 return 0; 159 } 160 161 static struct dma_fence **get_fences(struct sync_file *sync_file, 162 int *num_fences) 163 { 164 if (dma_fence_is_array(sync_file->fence)) { 165 struct dma_fence_array *array = to_dma_fence_array(sync_file->fence); 166 167 *num_fences = array->num_fences; 168 return array->fences; 169 } 170 171 *num_fences = 1; 172 return &sync_file->fence; 173 } 174 175 static void add_fence(struct dma_fence **fences, 176 int *i, struct dma_fence *fence) 177 { 178 fences[*i] = fence; 179 180 if (!dma_fence_is_signaled(fence)) { 181 dma_fence_get(fence); 182 (*i)++; 183 } 184 } 185 186 /** 187 * sync_file_merge() - merge two sync_files 188 * @name: name of new fence 189 * @a: sync_file a 190 * @b: sync_file b 191 * 192 * Creates a new sync_file which contains copies of all the fences in both 193 * @a and @b. @a and @b remain valid, independent sync_file. Returns the 194 * new merged sync_file or NULL in case of error. 195 */ 196 static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, 197 struct sync_file *b) 198 { 199 struct sync_file *sync_file; 200 struct dma_fence **fences, **nfences, **a_fences, **b_fences; 201 int i, i_a, i_b, num_fences, a_num_fences, b_num_fences; 202 203 sync_file = sync_file_alloc(); 204 if (!sync_file) 205 return NULL; 206 207 a_fences = get_fences(a, &a_num_fences); 208 b_fences = get_fences(b, &b_num_fences); 209 if (a_num_fences > INT_MAX - b_num_fences) 210 return NULL; 211 212 num_fences = a_num_fences + b_num_fences; 213 214 fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); 215 if (!fences) 216 goto err; 217 218 /* 219 * Assume sync_file a and b are both ordered and have no 220 * duplicates with the same context. 221 * 222 * If a sync_file can only be created with sync_file_merge 223 * and sync_file_create, this is a reasonable assumption. 224 */ 225 for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) { 226 struct dma_fence *pt_a = a_fences[i_a]; 227 struct dma_fence *pt_b = b_fences[i_b]; 228 229 if (pt_a->context < pt_b->context) { 230 add_fence(fences, &i, pt_a); 231 232 i_a++; 233 } else if (pt_a->context > pt_b->context) { 234 add_fence(fences, &i, pt_b); 235 236 i_b++; 237 } else { 238 if (pt_a->seqno - pt_b->seqno <= INT_MAX) 239 add_fence(fences, &i, pt_a); 240 else 241 add_fence(fences, &i, pt_b); 242 243 i_a++; 244 i_b++; 245 } 246 } 247 248 for (; i_a < a_num_fences; i_a++) 249 add_fence(fences, &i, a_fences[i_a]); 250 251 for (; i_b < b_num_fences; i_b++) 252 add_fence(fences, &i, b_fences[i_b]); 253 254 if (i == 0) 255 fences[i++] = dma_fence_get(a_fences[0]); 256 257 if (num_fences > i) { 258 nfences = krealloc(fences, i * sizeof(*fences), 259 GFP_KERNEL); 260 if (!nfences) 261 goto err; 262 263 fences = nfences; 264 } 265 266 if (sync_file_set_fence(sync_file, fences, i) < 0) { 267 kfree(fences); 268 goto err; 269 } 270 271 strlcpy(sync_file->name, name, sizeof(sync_file->name)); 272 return sync_file; 273 274 err: 275 fput(sync_file->file); 276 return NULL; 277 278 } 279 280 static void sync_file_free(struct kref *kref) 281 { 282 struct sync_file *sync_file = container_of(kref, struct sync_file, 283 kref); 284 285 if (test_bit(POLL_ENABLED, &sync_file->fence->flags)) 286 dma_fence_remove_callback(sync_file->fence, &sync_file->cb); 287 dma_fence_put(sync_file->fence); 288 kfree(sync_file); 289 } 290 291 static int sync_file_release(struct inode *inode, struct file *file) 292 { 293 struct sync_file *sync_file = file->private_data; 294 295 kref_put(&sync_file->kref, sync_file_free); 296 return 0; 297 } 298 299 static unsigned int sync_file_poll(struct file *file, poll_table *wait) 300 { 301 struct sync_file *sync_file = file->private_data; 302 303 poll_wait(file, &sync_file->wq, wait); 304 305 if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) { 306 if (dma_fence_add_callback(sync_file->fence, &sync_file->cb, 307 fence_check_cb_func) < 0) 308 wake_up_all(&sync_file->wq); 309 } 310 311 return dma_fence_is_signaled(sync_file->fence) ? POLLIN : 0; 312 } 313 314 static long sync_file_ioctl_merge(struct sync_file *sync_file, 315 unsigned long arg) 316 { 317 int fd = get_unused_fd_flags(O_CLOEXEC); 318 int err; 319 struct sync_file *fence2, *fence3; 320 struct sync_merge_data data; 321 322 if (fd < 0) 323 return fd; 324 325 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { 326 err = -EFAULT; 327 goto err_put_fd; 328 } 329 330 if (data.flags || data.pad) { 331 err = -EINVAL; 332 goto err_put_fd; 333 } 334 335 fence2 = sync_file_fdget(data.fd2); 336 if (!fence2) { 337 err = -ENOENT; 338 goto err_put_fd; 339 } 340 341 data.name[sizeof(data.name) - 1] = '\0'; 342 fence3 = sync_file_merge(data.name, sync_file, fence2); 343 if (!fence3) { 344 err = -ENOMEM; 345 goto err_put_fence2; 346 } 347 348 data.fence = fd; 349 if (copy_to_user((void __user *)arg, &data, sizeof(data))) { 350 err = -EFAULT; 351 goto err_put_fence3; 352 } 353 354 fd_install(fd, fence3->file); 355 fput(fence2->file); 356 return 0; 357 358 err_put_fence3: 359 fput(fence3->file); 360 361 err_put_fence2: 362 fput(fence2->file); 363 364 err_put_fd: 365 put_unused_fd(fd); 366 return err; 367 } 368 369 static void sync_fill_fence_info(struct dma_fence *fence, 370 struct sync_fence_info *info) 371 { 372 strlcpy(info->obj_name, fence->ops->get_timeline_name(fence), 373 sizeof(info->obj_name)); 374 strlcpy(info->driver_name, fence->ops->get_driver_name(fence), 375 sizeof(info->driver_name)); 376 377 info->status = dma_fence_get_status(fence); 378 info->timestamp_ns = ktime_to_ns(fence->timestamp); 379 } 380 381 static long sync_file_ioctl_fence_info(struct sync_file *sync_file, 382 unsigned long arg) 383 { 384 struct sync_file_info info; 385 struct sync_fence_info *fence_info = NULL; 386 struct dma_fence **fences; 387 __u32 size; 388 int num_fences, ret, i; 389 390 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 391 return -EFAULT; 392 393 if (info.flags || info.pad) 394 return -EINVAL; 395 396 fences = get_fences(sync_file, &num_fences); 397 398 /* 399 * Passing num_fences = 0 means that userspace doesn't want to 400 * retrieve any sync_fence_info. If num_fences = 0 we skip filling 401 * sync_fence_info and return the actual number of fences on 402 * info->num_fences. 403 */ 404 if (!info.num_fences) 405 goto no_fences; 406 407 if (info.num_fences < num_fences) 408 return -EINVAL; 409 410 size = num_fences * sizeof(*fence_info); 411 fence_info = kzalloc(size, GFP_KERNEL); 412 if (!fence_info) 413 return -ENOMEM; 414 415 for (i = 0; i < num_fences; i++) 416 sync_fill_fence_info(fences[i], &fence_info[i]); 417 418 if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, 419 size)) { 420 ret = -EFAULT; 421 goto out; 422 } 423 424 no_fences: 425 strlcpy(info.name, sync_file->name, sizeof(info.name)); 426 info.status = dma_fence_is_signaled(sync_file->fence); 427 info.num_fences = num_fences; 428 429 if (copy_to_user((void __user *)arg, &info, sizeof(info))) 430 ret = -EFAULT; 431 else 432 ret = 0; 433 434 out: 435 kfree(fence_info); 436 437 return ret; 438 } 439 440 static long sync_file_ioctl(struct file *file, unsigned int cmd, 441 unsigned long arg) 442 { 443 struct sync_file *sync_file = file->private_data; 444 445 switch (cmd) { 446 case SYNC_IOC_MERGE: 447 return sync_file_ioctl_merge(sync_file, arg); 448 449 case SYNC_IOC_FILE_INFO: 450 return sync_file_ioctl_fence_info(sync_file, arg); 451 452 default: 453 return -ENOTTY; 454 } 455 } 456 457 static const struct file_operations sync_file_fops = { 458 .release = sync_file_release, 459 .poll = sync_file_poll, 460 .unlocked_ioctl = sync_file_ioctl, 461 .compat_ioctl = sync_file_ioctl, 462 }; 463