Pileus Git - ~andy/linux/blob - drivers/gpu/drm/ttm/ttm_object.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2009-2013 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27 /*
  28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  29  *
  30  * While no substantial code is shared, the prime code is inspired by
  31  * drm_prime.c, with
  32  * Authors:
  33  *      Dave Airlie <airlied@redhat.com>
  34  *      Rob Clark <rob.clark@linaro.org>
  35  */
  36 /** @file ttm_ref_object.c
  37  *
  38  * Base- and reference object implementation for the various
  39  * ttm objects. Implements reference counting, minimal security checks
  40  * and release on file close.
  41  */
  42
  43
  44 /**
  45  * struct ttm_object_file
  46  *
  47  * @tdev: Pointer to the ttm_object_device.
  48  *
  49  * @lock: Lock that protects the ref_list list and the
  50  * ref_hash hash tables.
  51  *
  52  * @ref_list: List of ttm_ref_objects to be destroyed at
  53  * file release.
  54  *
  55  * @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
  56  * for fast lookup of ref objects given a base object.
  57  */
  58
  59 #define pr_fmt(fmt) "[TTM] " fmt
  60
  61 #include <drm/ttm/ttm_object.h>
  62 #include <drm/ttm/ttm_module.h>
  63 #include <linux/list.h>
  64 #include <linux/spinlock.h>
  65 #include <linux/slab.h>
  66 #include <linux/module.h>
  67 #include <linux/atomic.h>
  68
  69 struct ttm_object_file {
  70         struct ttm_object_device *tdev;
  71         spinlock_t lock;
  72         struct list_head ref_list;
  73         struct drm_open_hash ref_hash[TTM_REF_NUM];
  74         struct kref refcount;
  75 };
  76
  77 /**
  78  * struct ttm_object_device
  79  *
  80  * @object_lock: lock that protects the object_hash hash table.
  81  *
  82  * @object_hash: hash table for fast lookup of object global names.
  83  *
  84  * @object_count: Per device object count.
  85  *
  86  * This is the per-device data structure needed for ttm object management.
  87  */
  88
  89 struct ttm_object_device {
  90         spinlock_t object_lock;
  91         struct drm_open_hash object_hash;
  92         atomic_t object_count;
  93         struct ttm_mem_global *mem_glob;
  94         struct dma_buf_ops ops;
  95         void (*dmabuf_release)(struct dma_buf *dma_buf);
  96         size_t dma_buf_size;
  97 };
  98
  99 /**
 100  * struct ttm_ref_object
 101  *
 102  * @hash: Hash entry for the per-file object reference hash.
 103  *
 104  * @head: List entry for the per-file list of ref-objects.
 105  *
 106  * @kref: Ref count.
 107  *
 108  * @obj: Base object this ref object is referencing.
 109  *
 110  * @ref_type: Type of ref object.
 111  *
 112  * This is similar to an idr object, but it also has a hash table entry
 113  * that allows lookup with a pointer to the referenced object as a key. In
 114  * that way, one can easily detect whether a base object is referenced by
 115  * a particular ttm_object_file. It also carries a ref count to avoid creating
 116  * multiple ref objects if a ttm_object_file references the same base
 117  * object more than once.
 118  */
 119
 120 struct ttm_ref_object {
 121         struct rcu_head rcu_head;
 122         struct drm_hash_item hash;
 123         struct list_head head;
 124         struct kref kref;
 125         enum ttm_ref_type ref_type;
 126         struct ttm_base_object *obj;
 127         struct ttm_object_file *tfile;
 128 };
 129
 130 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
 131
 132 static inline struct ttm_object_file *
 133 ttm_object_file_ref(struct ttm_object_file *tfile)
 134 {
 135         kref_get(&tfile->refcount);
 136         return tfile;
 137 }
 138
 139 static void ttm_object_file_destroy(struct kref *kref)
 140 {
 141         struct ttm_object_file *tfile =
 142                 container_of(kref, struct ttm_object_file, refcount);
 143
 144         kfree(tfile);
 145 }
 146
 147
 148 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
 149 {
 150         struct ttm_object_file *tfile = *p_tfile;
 151
 152         *p_tfile = NULL;
 153         kref_put(&tfile->refcount, ttm_object_file_destroy);
 154 }
 155
 156
 157 int ttm_base_object_init(struct ttm_object_file *tfile,
 158                          struct ttm_base_object *base,
 159                          bool shareable,
 160                          enum ttm_object_type object_type,
 161                          void (*refcount_release) (struct ttm_base_object **),
 162                          void (*ref_obj_release) (struct ttm_base_object *,
 163                                                   enum ttm_ref_type ref_type))
 164 {
 165         struct ttm_object_device *tdev = tfile->tdev;
 166         int ret;
 167
 168         base->shareable = shareable;
 169         base->tfile = ttm_object_file_ref(tfile);
 170         base->refcount_release = refcount_release;
 171         base->ref_obj_release = ref_obj_release;
 172         base->object_type = object_type;
 173         kref_init(&base->refcount);
 174         spin_lock(&tdev->object_lock);
 175         ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
 176                                             &base->hash,
 177                                             (unsigned long)base, 31, 0, 0);
 178         spin_unlock(&tdev->object_lock);
 179         if (unlikely(ret != 0))
 180                 goto out_err0;
 181
 182         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
 183         if (unlikely(ret != 0))
 184                 goto out_err1;
 185
 186         ttm_base_object_unref(&base);
 187
 188         return 0;
 189 out_err1:
 190         spin_lock(&tdev->object_lock);
 191         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 192         spin_unlock(&tdev->object_lock);
 193 out_err0:
 194         return ret;
 195 }
 196 EXPORT_SYMBOL(ttm_base_object_init);
 197
 198 static void ttm_release_base(struct kref *kref)
 199 {
 200         struct ttm_base_object *base =
 201             container_of(kref, struct ttm_base_object, refcount);
 202         struct ttm_object_device *tdev = base->tfile->tdev;
 203
 204         spin_lock(&tdev->object_lock);
 205         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 206         spin_unlock(&tdev->object_lock);
 207
 208         /*
 209          * Note: We don't use synchronize_rcu() here because it's far
 210          * too slow. It's up to the user to free the object using
 211          * call_rcu() or ttm_base_object_kfree().
 212          */
 213
 214         ttm_object_file_unref(&base->tfile);
 215         if (base->refcount_release)
 216                 base->refcount_release(&base);
 217 }
 218
 219 void ttm_base_object_unref(struct ttm_base_object **p_base)
 220 {
 221         struct ttm_base_object *base = *p_base;
 222
 223         *p_base = NULL;
 224
 225         kref_put(&base->refcount, ttm_release_base);
 226 }
 227 EXPORT_SYMBOL(ttm_base_object_unref);
 228
 229 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 230                                                uint32_t key)
 231 {
 232         struct ttm_base_object *base = NULL;
 233         struct drm_hash_item *hash;
 234         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 235         int ret;
 236
 237         rcu_read_lock();
 238         ret = drm_ht_find_item_rcu(ht, key, &hash);
 239
 240         if (likely(ret == 0)) {
 241                 base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
 242                 if (!kref_get_unless_zero(&base->refcount))
 243                         base = NULL;
 244         }
 245         rcu_read_unlock();
 246
 247         return base;
 248 }
 249 EXPORT_SYMBOL(ttm_base_object_lookup);
 250
 251 struct ttm_base_object *
 252 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
 253 {
 254         struct ttm_base_object *base = NULL;
 255         struct drm_hash_item *hash;
 256         struct drm_open_hash *ht = &tdev->object_hash;
 257         int ret;
 258
 259         rcu_read_lock();
 260         ret = drm_ht_find_item_rcu(ht, key, &hash);
 261
 262         if (likely(ret == 0)) {
 263                 base = drm_hash_entry(hash, struct ttm_base_object, hash);
 264                 if (!kref_get_unless_zero(&base->refcount))
 265                         base = NULL;
 266         }
 267         rcu_read_unlock();
 268
 269         return base;
 270 }
 271 EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);
 272
 273 int ttm_ref_object_add(struct ttm_object_file *tfile,
 274                        struct ttm_base_object *base,
 275                        enum ttm_ref_type ref_type, bool *existed)
 276 {
 277         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 278         struct ttm_ref_object *ref;
 279         struct drm_hash_item *hash;
 280         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 281         int ret = -EINVAL;
 282
 283         if (base->tfile != tfile && !base->shareable)
 284                 return -EPERM;
 285
 286         if (existed != NULL)
 287                 *existed = true;
 288
 289         while (ret == -EINVAL) {
 290                 rcu_read_lock();
 291                 ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);
 292
 293                 if (ret == 0) {
 294                         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 295                         if (!kref_get_unless_zero(&ref->kref)) {
 296                                 rcu_read_unlock();
 297                                 break;
 298                         }
 299                 }
 300
 301                 rcu_read_unlock();
 302                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
 303                                            false, false);
 304                 if (unlikely(ret != 0))
 305                         return ret;
 306                 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
 307                 if (unlikely(ref == NULL)) {
 308                         ttm_mem_global_free(mem_glob, sizeof(*ref));
 309                         return -ENOMEM;
 310                 }
 311
 312                 ref->hash.key = base->hash.key;
 313                 ref->obj = base;
 314                 ref->tfile = tfile;
 315                 ref->ref_type = ref_type;
 316                 kref_init(&ref->kref);
 317
 318                 spin_lock(&tfile->lock);
 319                 ret = drm_ht_insert_item_rcu(ht, &ref->hash);
 320
 321                 if (likely(ret == 0)) {
 322                         list_add_tail(&ref->head, &tfile->ref_list);
 323                         kref_get(&base->refcount);
 324                         spin_unlock(&tfile->lock);
 325                         if (existed != NULL)
 326                                 *existed = false;
 327                         break;
 328                 }
 329
 330                 spin_unlock(&tfile->lock);
 331                 BUG_ON(ret != -EINVAL);
 332
 333                 ttm_mem_global_free(mem_glob, sizeof(*ref));
 334                 kfree(ref);
 335         }
 336
 337         return ret;
 338 }
 339 EXPORT_SYMBOL(ttm_ref_object_add);
 340
 341 static void ttm_ref_object_release(struct kref *kref)
 342 {
 343         struct ttm_ref_object *ref =
 344             container_of(kref, struct ttm_ref_object, kref);
 345         struct ttm_base_object *base = ref->obj;
 346         struct ttm_object_file *tfile = ref->tfile;
 347         struct drm_open_hash *ht;
 348         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 349
 350         ht = &tfile->ref_hash[ref->ref_type];
 351         (void)drm_ht_remove_item_rcu(ht, &ref->hash);
 352         list_del(&ref->head);
 353         spin_unlock(&tfile->lock);
 354
 355         if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
 356                 base->ref_obj_release(base, ref->ref_type);
 357
 358         ttm_base_object_unref(&ref->obj);
 359         ttm_mem_global_free(mem_glob, sizeof(*ref));
 360         kfree_rcu(ref, rcu_head);
 361         spin_lock(&tfile->lock);
 362 }
 363
 364 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 365                               unsigned long key, enum ttm_ref_type ref_type)
 366 {
 367         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 368         struct ttm_ref_object *ref;
 369         struct drm_hash_item *hash;
 370         int ret;
 371
 372         spin_lock(&tfile->lock);
 373         ret = drm_ht_find_item(ht, key, &hash);
 374         if (unlikely(ret != 0)) {
 375                 spin_unlock(&tfile->lock);
 376                 return -EINVAL;
 377         }
 378         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 379         kref_put(&ref->kref, ttm_ref_object_release);
 380         spin_unlock(&tfile->lock);
 381         return 0;
 382 }
 383 EXPORT_SYMBOL(ttm_ref_object_base_unref);
 384
 385 void ttm_object_file_release(struct ttm_object_file **p_tfile)
 386 {
 387         struct ttm_ref_object *ref;
 388         struct list_head *list;
 389         unsigned int i;
 390         struct ttm_object_file *tfile = *p_tfile;
 391
 392         *p_tfile = NULL;
 393         spin_lock(&tfile->lock);
 394
 395         /*
 396          * Since we release the lock within the loop, we have to
 397          * restart it from the beginning each time.
 398          */
 399
 400         while (!list_empty(&tfile->ref_list)) {
 401                 list = tfile->ref_list.next;
 402                 ref = list_entry(list, struct ttm_ref_object, head);
 403                 ttm_ref_object_release(&ref->kref);
 404         }
 405
 406         for (i = 0; i < TTM_REF_NUM; ++i)
 407                 drm_ht_remove(&tfile->ref_hash[i]);
 408
 409         spin_unlock(&tfile->lock);
 410         ttm_object_file_unref(&tfile);
 411 }
 412 EXPORT_SYMBOL(ttm_object_file_release);
 413
 414 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 415                                              unsigned int hash_order)
 416 {
 417         struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
 418         unsigned int i;
 419         unsigned int j = 0;
 420         int ret;
 421
 422         if (unlikely(tfile == NULL))
 423                 return NULL;
 424
 425         spin_lock_init(&tfile->lock);
 426         tfile->tdev = tdev;
 427         kref_init(&tfile->refcount);
 428         INIT_LIST_HEAD(&tfile->ref_list);
 429
 430         for (i = 0; i < TTM_REF_NUM; ++i) {
 431                 ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
 432                 if (ret) {
 433                         j = i;
 434                         goto out_err;
 435                 }
 436         }
 437
 438         return tfile;
 439 out_err:
 440         for (i = 0; i < j; ++i)
 441                 drm_ht_remove(&tfile->ref_hash[i]);
 442
 443         kfree(tfile);
 444
 445         return NULL;
 446 }
 447 EXPORT_SYMBOL(ttm_object_file_init);
 448
 449 struct ttm_object_device *
 450 ttm_object_device_init(struct ttm_mem_global *mem_glob,
 451                        unsigned int hash_order,
 452                        const struct dma_buf_ops *ops)
 453 {
 454         struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
 455         int ret;
 456
 457         if (unlikely(tdev == NULL))
 458                 return NULL;
 459
 460         tdev->mem_glob = mem_glob;
 461         spin_lock_init(&tdev->object_lock);
 462         atomic_set(&tdev->object_count, 0);
 463         ret = drm_ht_create(&tdev->object_hash, hash_order);
 464         if (ret != 0)
 465                 goto out_no_object_hash;
 466
 467         tdev->ops = *ops;
 468         tdev->dmabuf_release = tdev->ops.release;
 469         tdev->ops.release = ttm_prime_dmabuf_release;
 470         tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
 471                 ttm_round_pot(sizeof(struct file));
 472         return tdev;
 473
 474 out_no_object_hash:
 475         kfree(tdev);
 476         return NULL;
 477 }
 478 EXPORT_SYMBOL(ttm_object_device_init);
 479
 480 void ttm_object_device_release(struct ttm_object_device **p_tdev)
 481 {
 482         struct ttm_object_device *tdev = *p_tdev;
 483
 484         *p_tdev = NULL;
 485
 486         spin_lock(&tdev->object_lock);
 487         drm_ht_remove(&tdev->object_hash);
 488         spin_unlock(&tdev->object_lock);
 489
 490         kfree(tdev);
 491 }
 492 EXPORT_SYMBOL(ttm_object_device_release);
 493
 494 /**
 495  * get_dma_buf_unless_doomed - get a dma_buf reference if possible.
 496  *
 497  * @dma_buf: Non-refcounted pointer to a struct dma-buf.
 498  *
 499  * Obtain a file reference from a lookup structure that doesn't refcount
 500  * the file, but synchronizes with its release method to make sure it has
 501  * not been freed yet. See for example kref_get_unless_zero documentation.
 502  * Returns true if refcounting succeeds, false otherwise.
 503  *
 504  * Nobody really wants this as a public API yet, so let it mature here
 505  * for some time...
 506  */
 507 static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
 508 {
 509         return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
 510 }
 511
 512 /**
 513  * ttm_prime_refcount_release - refcount release method for a prime object.
 514  *
 515  * @p_base: Pointer to ttm_base_object pointer.
 516  *
 517  * This is a wrapper that calls the refcount_release founction of the
 518  * underlying object. At the same time it cleans up the prime object.
 519  * This function is called when all references to the base object we
 520  * derive from are gone.
 521  */
 522 static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
 523 {
 524         struct ttm_base_object *base = *p_base;
 525         struct ttm_prime_object *prime;
 526
 527         *p_base = NULL;
 528         prime = container_of(base, struct ttm_prime_object, base);
 529         BUG_ON(prime->dma_buf != NULL);
 530         mutex_destroy(&prime->mutex);
 531         if (prime->refcount_release)
 532                 prime->refcount_release(&base);
 533 }
 534
 535 /**
 536  * ttm_prime_dmabuf_release - Release method for the dma-bufs we export
 537  *
 538  * @dma_buf:
 539  *
 540  * This function first calls the dma_buf release method the driver
 541  * provides. Then it cleans up our dma_buf pointer used for lookup,
 542  * and finally releases the reference the dma_buf has on our base
 543  * object.
 544  */
 545 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
 546 {
 547         struct ttm_prime_object *prime =
 548                 (struct ttm_prime_object *) dma_buf->priv;
 549         struct ttm_base_object *base = &prime->base;
 550         struct ttm_object_device *tdev = base->tfile->tdev;
 551
 552         if (tdev->dmabuf_release)
 553                 tdev->dmabuf_release(dma_buf);
 554         mutex_lock(&prime->mutex);
 555         if (prime->dma_buf == dma_buf)
 556                 prime->dma_buf = NULL;
 557         mutex_unlock(&prime->mutex);
 558         ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
 559         ttm_base_object_unref(&base);
 560 }
 561
 562 /**
 563  * ttm_prime_fd_to_handle - Get a base object handle from a prime fd
 564  *
 565  * @tfile: A struct ttm_object_file identifying the caller.
 566  * @fd: The prime / dmabuf fd.
 567  * @handle: The returned handle.
 568  *
 569  * This function returns a handle to an object that previously exported
 570  * a dma-buf. Note that we don't handle imports yet, because we simply
 571  * have no consumers of that implementation.
 572  */
 573 int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
 574                            int fd, u32 *handle)
 575 {
 576         struct ttm_object_device *tdev = tfile->tdev;
 577         struct dma_buf *dma_buf;
 578         struct ttm_prime_object *prime;
 579         struct ttm_base_object *base;
 580         int ret;
 581
 582         dma_buf = dma_buf_get(fd);
 583         if (IS_ERR(dma_buf))
 584                 return PTR_ERR(dma_buf);
 585
 586         if (dma_buf->ops != &tdev->ops)
 587                 return -ENOSYS;
 588
 589         prime = (struct ttm_prime_object *) dma_buf->priv;
 590         base = &prime->base;
 591         *handle = base->hash.key;
 592         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
 593
 594         dma_buf_put(dma_buf);
 595
 596         return ret;
 597 }
 598 EXPORT_SYMBOL_GPL(ttm_prime_fd_to_handle);
 599
 600 /**
 601  * ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
 602  *
 603  * @tfile: Struct ttm_object_file identifying the caller.
 604  * @handle: Handle to the object we're exporting from.
 605  * @flags: flags for dma-buf creation. We just pass them on.
 606  * @prime_fd: The returned file descriptor.
 607  *
 608  */
 609 int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 610                            uint32_t handle, uint32_t flags,
 611                            int *prime_fd)
 612 {
 613         struct ttm_object_device *tdev = tfile->tdev;
 614         struct ttm_base_object *base;
 615         struct dma_buf *dma_buf;
 616         struct ttm_prime_object *prime;
 617         int ret;
 618
 619         base = ttm_base_object_lookup(tfile, handle);
 620         if (unlikely(base == NULL ||
 621                      base->object_type != ttm_prime_type)) {
 622                 ret = -ENOENT;
 623                 goto out_unref;
 624         }
 625
 626         prime = container_of(base, struct ttm_prime_object, base);
 627         if (unlikely(!base->shareable)) {
 628                 ret = -EPERM;
 629                 goto out_unref;
 630         }
 631
 632         ret = mutex_lock_interruptible(&prime->mutex);
 633         if (unlikely(ret != 0)) {
 634                 ret = -ERESTARTSYS;
 635                 goto out_unref;
 636         }
 637
 638         dma_buf = prime->dma_buf;
 639         if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
 640
 641                 /*
 642                  * Need to create a new dma_buf, with memory accounting.
 643                  */
 644                 ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
 645                                            false, true);
 646                 if (unlikely(ret != 0)) {
 647                         mutex_unlock(&prime->mutex);
 648                         goto out_unref;
 649                 }
 650
 651                 dma_buf = dma_buf_export(prime, &tdev->ops,
 652                                          prime->size, flags);
 653                 if (IS_ERR(dma_buf)) {
 654                         ret = PTR_ERR(dma_buf);
 655                         ttm_mem_global_free(tdev->mem_glob,
 656                                             tdev->dma_buf_size);
 657                         mutex_unlock(&prime->mutex);
 658                         goto out_unref;
 659                 }
 660
 661                 /*
 662                  * dma_buf has taken the base object reference
 663                  */
 664                 base = NULL;
 665                 prime->dma_buf = dma_buf;
 666         }
 667         mutex_unlock(&prime->mutex);
 668
 669         ret = dma_buf_fd(dma_buf, flags);
 670         if (ret >= 0) {
 671                 *prime_fd = ret;
 672                 ret = 0;
 673         } else
 674                 dma_buf_put(dma_buf);
 675
 676 out_unref:
 677         if (base)
 678                 ttm_base_object_unref(&base);
 679         return ret;
 680 }
 681 EXPORT_SYMBOL_GPL(ttm_prime_handle_to_fd);
 682
 683 /**
 684  * ttm_prime_object_init - Initialize a ttm_prime_object
 685  *
 686  * @tfile: struct ttm_object_file identifying the caller
 687  * @size: The size of the dma_bufs we export.
 688  * @prime: The object to be initialized.
 689  * @shareable: See ttm_base_object_init
 690  * @type: See ttm_base_object_init
 691  * @refcount_release: See ttm_base_object_init
 692  * @ref_obj_release: See ttm_base_object_init
 693  *
 694  * Initializes an object which is compatible with the drm_prime model
 695  * for data sharing between processes and devices.
 696  */
 697 int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
 698                           struct ttm_prime_object *prime, bool shareable,
 699                           enum ttm_object_type type,
 700                           void (*refcount_release) (struct ttm_base_object **),
 701                           void (*ref_obj_release) (struct ttm_base_object *,
 702                                                    enum ttm_ref_type ref_type))
 703 {
 704         mutex_init(&prime->mutex);
 705         prime->size = PAGE_ALIGN(size);
 706         prime->real_type = type;
 707         prime->dma_buf = NULL;
 708         prime->refcount_release = refcount_release;
 709         return ttm_base_object_init(tfile, &prime->base, shareable,
 710                                     ttm_prime_type,
 711                                     ttm_prime_refcount_release,
 712                                     ref_obj_release);
 713 }
 714 EXPORT_SYMBOL(ttm_prime_object_init);