drivers/gpu/drm/ttm/ttm_object.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2009-2013 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28 /*
  29  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  30  *
  31  * While no substantial code is shared, the prime code is inspired by
  32  * drm_prime.c, with
  33  * Authors:
  34  *      Dave Airlie <airlied@redhat.com>
  35  *      Rob Clark <rob.clark@linaro.org>
  36  */
  37 /** @file ttm_ref_object.c
  38  *
  39  * Base- and reference object implementation for the various
  40  * ttm objects. Implements reference counting, minimal security checks
  41  * and release on file close.
  42  */
  43
  44
  45 /**
  46  * struct ttm_object_file
  47  *
  48  * @tdev: Pointer to the ttm_object_device.
  49  *
  50  * @lock: Lock that protects the ref_list list and the
  51  * ref_hash hash tables.
  52  *
  53  * @ref_list: List of ttm_ref_objects to be destroyed at
  54  * file release.
  55  *
  56  * @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
  57  * for fast lookup of ref objects given a base object.
  58  */
  59
  60 #define pr_fmt(fmt) "[TTM] " fmt
  61
  62 #include <drm/ttm/ttm_object.h>
  63 #include <drm/ttm/ttm_module.h>
  64 #include <linux/list.h>
  65 #include <linux/spinlock.h>
  66 #include <linux/slab.h>
  67 #include <linux/module.h>
  68 #include <linux/atomic.h>
  69
  70 struct ttm_object_file {
  71         struct ttm_object_device *tdev;
  72         spinlock_t lock;
  73         struct list_head ref_list;
  74         struct drm_open_hash ref_hash[TTM_REF_NUM];
  75         struct kref refcount;
  76 };
  77
  78 /**
  79  * struct ttm_object_device
  80  *
  81  * @object_lock: lock that protects the object_hash hash table.
  82  *
  83  * @object_hash: hash table for fast lookup of object global names.
  84  *
  85  * @object_count: Per device object count.
  86  *
  87  * This is the per-device data structure needed for ttm object management.
  88  */
  89
  90 struct ttm_object_device {
  91         spinlock_t object_lock;
  92         struct drm_open_hash object_hash;
  93         atomic_t object_count;
  94         struct ttm_mem_global *mem_glob;
  95         struct dma_buf_ops ops;
  96         void (*dmabuf_release)(struct dma_buf *dma_buf);
  97         size_t dma_buf_size;
  98 };
  99
 100 /**
 101  * struct ttm_ref_object
 102  *
 103  * @hash: Hash entry for the per-file object reference hash.
 104  *
 105  * @head: List entry for the per-file list of ref-objects.
 106  *
 107  * @kref: Ref count.
 108  *
 109  * @obj: Base object this ref object is referencing.
 110  *
 111  * @ref_type: Type of ref object.
 112  *
 113  * This is similar to an idr object, but it also has a hash table entry
 114  * that allows lookup with a pointer to the referenced object as a key. In
 115  * that way, one can easily detect whether a base object is referenced by
 116  * a particular ttm_object_file. It also carries a ref count to avoid creating
 117  * multiple ref objects if a ttm_object_file references the same base
 118  * object more than once.
 119  */
 120
 121 struct ttm_ref_object {
 122         struct rcu_head rcu_head;
 123         struct drm_hash_item hash;
 124         struct list_head head;
 125         struct kref kref;
 126         enum ttm_ref_type ref_type;
 127         struct ttm_base_object *obj;
 128         struct ttm_object_file *tfile;
 129 };
 130
 131 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
 132
 133 static inline struct ttm_object_file *
 134 ttm_object_file_ref(struct ttm_object_file *tfile)
 135 {
 136         kref_get(&tfile->refcount);
 137         return tfile;
 138 }
 139
 140 static void ttm_object_file_destroy(struct kref *kref)
 141 {
 142         struct ttm_object_file *tfile =
 143                 container_of(kref, struct ttm_object_file, refcount);
 144
 145         kfree(tfile);
 146 }
 147
 148
 149 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
 150 {
 151         struct ttm_object_file *tfile = *p_tfile;
 152
 153         *p_tfile = NULL;
 154         kref_put(&tfile->refcount, ttm_object_file_destroy);
 155 }
 156
 157
 158 int ttm_base_object_init(struct ttm_object_file *tfile,
 159                          struct ttm_base_object *base,
 160                          bool shareable,
 161                          enum ttm_object_type object_type,
 162                          void (*refcount_release) (struct ttm_base_object **),
 163                          void (*ref_obj_release) (struct ttm_base_object *,
 164                                                   enum ttm_ref_type ref_type))
 165 {
 166         struct ttm_object_device *tdev = tfile->tdev;
 167         int ret;
 168
 169         base->shareable = shareable;
 170         base->tfile = ttm_object_file_ref(tfile);
 171         base->refcount_release = refcount_release;
 172         base->ref_obj_release = ref_obj_release;
 173         base->object_type = object_type;
 174         kref_init(&base->refcount);
 175         spin_lock(&tdev->object_lock);
 176         ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
 177                                             &base->hash,
 178                                             (unsigned long)base, 31, 0, 0);
 179         spin_unlock(&tdev->object_lock);
 180         if (unlikely(ret != 0))
 181                 goto out_err0;
 182
 183         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
 184         if (unlikely(ret != 0))
 185                 goto out_err1;
 186
 187         ttm_base_object_unref(&base);
 188
 189         return 0;
 190 out_err1:
 191         spin_lock(&tdev->object_lock);
 192         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 193         spin_unlock(&tdev->object_lock);
 194 out_err0:
 195         return ret;
 196 }
 197 EXPORT_SYMBOL(ttm_base_object_init);
 198
 199 static void ttm_release_base(struct kref *kref)
 200 {
 201         struct ttm_base_object *base =
 202             container_of(kref, struct ttm_base_object, refcount);
 203         struct ttm_object_device *tdev = base->tfile->tdev;
 204
 205         spin_lock(&tdev->object_lock);
 206         (void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
 207         spin_unlock(&tdev->object_lock);
 208
 209         /*
 210          * Note: We don't use synchronize_rcu() here because it's far
 211          * too slow. It's up to the user to free the object using
 212          * call_rcu() or ttm_base_object_kfree().
 213          */
 214
 215         ttm_object_file_unref(&base->tfile);
 216         if (base->refcount_release)
 217                 base->refcount_release(&base);
 218 }
 219
 220 void ttm_base_object_unref(struct ttm_base_object **p_base)
 221 {
 222         struct ttm_base_object *base = *p_base;
 223
 224         *p_base = NULL;
 225
 226         kref_put(&base->refcount, ttm_release_base);
 227 }
 228 EXPORT_SYMBOL(ttm_base_object_unref);
 229
 230 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 231                                                uint32_t key)
 232 {
 233         struct ttm_base_object *base = NULL;
 234         struct drm_hash_item *hash;
 235         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 236         int ret;
 237
 238         rcu_read_lock();
 239         ret = drm_ht_find_item_rcu(ht, key, &hash);
 240
 241         if (likely(ret == 0)) {
 242                 base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
 243                 if (!kref_get_unless_zero(&base->refcount))
 244                         base = NULL;
 245         }
 246         rcu_read_unlock();
 247
 248         return base;
 249 }
 250 EXPORT_SYMBOL(ttm_base_object_lookup);
 251
 252 struct ttm_base_object *
 253 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
 254 {
 255         struct ttm_base_object *base = NULL;
 256         struct drm_hash_item *hash;
 257         struct drm_open_hash *ht = &tdev->object_hash;
 258         int ret;
 259
 260         rcu_read_lock();
 261         ret = drm_ht_find_item_rcu(ht, key, &hash);
 262
 263         if (likely(ret == 0)) {
 264                 base = drm_hash_entry(hash, struct ttm_base_object, hash);
 265                 if (!kref_get_unless_zero(&base->refcount))
 266                         base = NULL;
 267         }
 268         rcu_read_unlock();
 269
 270         return base;
 271 }
 272 EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);
 273
 274 /**
 275  * ttm_ref_object_exists - Check whether a caller has a valid ref object
 276  * (has opened) a base object.
 277  *
 278  * @tfile: Pointer to a struct ttm_object_file identifying the caller.
 279  * @base: Pointer to a struct base object.
 280  *
 281  * Checks wether the caller identified by @tfile has put a valid USAGE
 282  * reference object on the base object identified by @base.
 283  */
 284 bool ttm_ref_object_exists(struct ttm_object_file *tfile,
 285                            struct ttm_base_object *base)
 286 {
 287         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 288         struct drm_hash_item *hash;
 289         struct ttm_ref_object *ref;
 290
 291         rcu_read_lock();
 292         if (unlikely(drm_ht_find_item_rcu(ht, base->hash.key, &hash) != 0))
 293                 goto out_false;
 294
 295         /*
 296          * Verify that the ref object is really pointing to our base object.
 297          * Our base object could actually be dead, and the ref object pointing
 298          * to another base object with the same handle.
 299          */
 300         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 301         if (unlikely(base != ref->obj))
 302                 goto out_false;
 303
 304         /*
 305          * Verify that the ref->obj pointer was actually valid!
 306          */
 307         rmb();
 308         if (unlikely(kref_read(&ref->kref) == 0))
 309                 goto out_false;
 310
 311         rcu_read_unlock();
 312         return true;
 313
 314  out_false:
 315         rcu_read_unlock();
 316         return false;
 317 }
 318 EXPORT_SYMBOL(ttm_ref_object_exists);
 319
 320 int ttm_ref_object_add(struct ttm_object_file *tfile,
 321                        struct ttm_base_object *base,
 322                        enum ttm_ref_type ref_type, bool *existed,
 323                        bool require_existed)
 324 {
 325         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 326         struct ttm_ref_object *ref;
 327         struct drm_hash_item *hash;
 328         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 329         struct ttm_operation_ctx ctx = {
 330                 .interruptible = false,
 331                 .no_wait_gpu = false
 332         };
 333         int ret = -EINVAL;
 334
 335         if (base->tfile != tfile && !base->shareable)
 336                 return -EPERM;
 337
 338         if (existed != NULL)
 339                 *existed = true;
 340
 341         while (ret == -EINVAL) {
 342                 rcu_read_lock();
 343                 ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);
 344
 345                 if (ret == 0) {
 346                         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 347                         if (kref_get_unless_zero(&ref->kref)) {
 348                                 rcu_read_unlock();
 349                                 break;
 350                         }
 351                 }
 352
 353                 rcu_read_unlock();
 354                 if (require_existed)
 355                         return -EPERM;
 356
 357                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
 358                                            &ctx);
 359                 if (unlikely(ret != 0))
 360                         return ret;
 361                 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
 362                 if (unlikely(ref == NULL)) {
 363                         ttm_mem_global_free(mem_glob, sizeof(*ref));
 364                         return -ENOMEM;
 365                 }
 366
 367                 ref->hash.key = base->hash.key;
 368                 ref->obj = base;
 369                 ref->tfile = tfile;
 370                 ref->ref_type = ref_type;
 371                 kref_init(&ref->kref);
 372
 373                 spin_lock(&tfile->lock);
 374                 ret = drm_ht_insert_item_rcu(ht, &ref->hash);
 375
 376                 if (likely(ret == 0)) {
 377                         list_add_tail(&ref->head, &tfile->ref_list);
 378                         kref_get(&base->refcount);
 379                         spin_unlock(&tfile->lock);
 380                         if (existed != NULL)
 381                                 *existed = false;
 382                         break;
 383                 }
 384
 385                 spin_unlock(&tfile->lock);
 386                 BUG_ON(ret != -EINVAL);
 387
 388                 ttm_mem_global_free(mem_glob, sizeof(*ref));
 389                 kfree(ref);
 390         }
 391
 392         return ret;
 393 }
 394 EXPORT_SYMBOL(ttm_ref_object_add);
 395
 396 static void ttm_ref_object_release(struct kref *kref)
 397 {
 398         struct ttm_ref_object *ref =
 399             container_of(kref, struct ttm_ref_object, kref);
 400         struct ttm_base_object *base = ref->obj;
 401         struct ttm_object_file *tfile = ref->tfile;
 402         struct drm_open_hash *ht;
 403         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 404
 405         ht = &tfile->ref_hash[ref->ref_type];
 406         (void)drm_ht_remove_item_rcu(ht, &ref->hash);
 407         list_del(&ref->head);
 408         spin_unlock(&tfile->lock);
 409
 410         if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
 411                 base->ref_obj_release(base, ref->ref_type);
 412
 413         ttm_base_object_unref(&ref->obj);
 414         ttm_mem_global_free(mem_glob, sizeof(*ref));
 415         kfree_rcu(ref, rcu_head);
 416         spin_lock(&tfile->lock);
 417 }
 418
 419 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 420                               unsigned long key, enum ttm_ref_type ref_type)
 421 {
 422         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 423         struct ttm_ref_object *ref;
 424         struct drm_hash_item *hash;
 425         int ret;
 426
 427         spin_lock(&tfile->lock);
 428         ret = drm_ht_find_item(ht, key, &hash);
 429         if (unlikely(ret != 0)) {
 430                 spin_unlock(&tfile->lock);
 431                 return -EINVAL;
 432         }
 433         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 434         kref_put(&ref->kref, ttm_ref_object_release);
 435         spin_unlock(&tfile->lock);
 436         return 0;
 437 }
 438 EXPORT_SYMBOL(ttm_ref_object_base_unref);
 439
 440 void ttm_object_file_release(struct ttm_object_file **p_tfile)
 441 {
 442         struct ttm_ref_object *ref;
 443         struct list_head *list;
 444         unsigned int i;
 445         struct ttm_object_file *tfile = *p_tfile;
 446
 447         *p_tfile = NULL;
 448         spin_lock(&tfile->lock);
 449
 450         /*
 451          * Since we release the lock within the loop, we have to
 452          * restart it from the beginning each time.
 453          */
 454
 455         while (!list_empty(&tfile->ref_list)) {
 456                 list = tfile->ref_list.next;
 457                 ref = list_entry(list, struct ttm_ref_object, head);
 458                 ttm_ref_object_release(&ref->kref);
 459         }
 460
 461         spin_unlock(&tfile->lock);
 462         for (i = 0; i < TTM_REF_NUM; ++i)
 463                 drm_ht_remove(&tfile->ref_hash[i]);
 464
 465         ttm_object_file_unref(&tfile);
 466 }
 467 EXPORT_SYMBOL(ttm_object_file_release);
 468
 469 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 470                                              unsigned int hash_order)
 471 {
 472         struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
 473         unsigned int i;
 474         unsigned int j = 0;
 475         int ret;
 476
 477         if (unlikely(tfile == NULL))
 478                 return NULL;
 479
 480         spin_lock_init(&tfile->lock);
 481         tfile->tdev = tdev;
 482         kref_init(&tfile->refcount);
 483         INIT_LIST_HEAD(&tfile->ref_list);
 484
 485         for (i = 0; i < TTM_REF_NUM; ++i) {
 486                 ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
 487                 if (ret) {
 488                         j = i;
 489                         goto out_err;
 490                 }
 491         }
 492
 493         return tfile;
 494 out_err:
 495         for (i = 0; i < j; ++i)
 496                 drm_ht_remove(&tfile->ref_hash[i]);
 497
 498         kfree(tfile);
 499
 500         return NULL;
 501 }
 502 EXPORT_SYMBOL(ttm_object_file_init);
 503
 504 struct ttm_object_device *
 505 ttm_object_device_init(struct ttm_mem_global *mem_glob,
 506                        unsigned int hash_order,
 507                        const struct dma_buf_ops *ops)
 508 {
 509         struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
 510         int ret;
 511
 512         if (unlikely(tdev == NULL))
 513                 return NULL;
 514
 515         tdev->mem_glob = mem_glob;
 516         spin_lock_init(&tdev->object_lock);
 517         atomic_set(&tdev->object_count, 0);
 518         ret = drm_ht_create(&tdev->object_hash, hash_order);
 519         if (ret != 0)
 520                 goto out_no_object_hash;
 521
 522         tdev->ops = *ops;
 523         tdev->dmabuf_release = tdev->ops.release;
 524         tdev->ops.release = ttm_prime_dmabuf_release;
 525         tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
 526                 ttm_round_pot(sizeof(struct file));
 527         return tdev;
 528
 529 out_no_object_hash:
 530         kfree(tdev);
 531         return NULL;
 532 }
 533 EXPORT_SYMBOL(ttm_object_device_init);
 534
 535 void ttm_object_device_release(struct ttm_object_device **p_tdev)
 536 {
 537         struct ttm_object_device *tdev = *p_tdev;
 538
 539         *p_tdev = NULL;
 540
 541         drm_ht_remove(&tdev->object_hash);
 542
 543         kfree(tdev);
 544 }
 545 EXPORT_SYMBOL(ttm_object_device_release);
 546
 547 /**
 548  * get_dma_buf_unless_doomed - get a dma_buf reference if possible.
 549  *
 550  * @dma_buf: Non-refcounted pointer to a struct dma-buf.
 551  *
 552  * Obtain a file reference from a lookup structure that doesn't refcount
 553  * the file, but synchronizes with its release method to make sure it has
 554  * not been freed yet. See for example kref_get_unless_zero documentation.
 555  * Returns true if refcounting succeeds, false otherwise.
 556  *
 557  * Nobody really wants this as a public API yet, so let it mature here
 558  * for some time...
 559  */
 560 static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
 561 {
 562         return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
 563 }
 564
 565 /**
 566  * ttm_prime_refcount_release - refcount release method for a prime object.
 567  *
 568  * @p_base: Pointer to ttm_base_object pointer.
 569  *
 570  * This is a wrapper that calls the refcount_release founction of the
 571  * underlying object. At the same time it cleans up the prime object.
 572  * This function is called when all references to the base object we
 573  * derive from are gone.
 574  */
 575 static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
 576 {
 577         struct ttm_base_object *base = *p_base;
 578         struct ttm_prime_object *prime;
 579
 580         *p_base = NULL;
 581         prime = container_of(base, struct ttm_prime_object, base);
 582         BUG_ON(prime->dma_buf != NULL);
 583         mutex_destroy(&prime->mutex);
 584         if (prime->refcount_release)
 585                 prime->refcount_release(&base);
 586 }
 587
 588 /**
 589  * ttm_prime_dmabuf_release - Release method for the dma-bufs we export
 590  *
 591  * @dma_buf:
 592  *
 593  * This function first calls the dma_buf release method the driver
 594  * provides. Then it cleans up our dma_buf pointer used for lookup,
 595  * and finally releases the reference the dma_buf has on our base
 596  * object.
 597  */
 598 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
 599 {
 600         struct ttm_prime_object *prime =
 601                 (struct ttm_prime_object *) dma_buf->priv;
 602         struct ttm_base_object *base = &prime->base;
 603         struct ttm_object_device *tdev = base->tfile->tdev;
 604
 605         if (tdev->dmabuf_release)
 606                 tdev->dmabuf_release(dma_buf);
 607         mutex_lock(&prime->mutex);
 608         if (prime->dma_buf == dma_buf)
 609                 prime->dma_buf = NULL;
 610         mutex_unlock(&prime->mutex);
 611         ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
 612         ttm_base_object_unref(&base);
 613 }
 614
 615 /**
 616  * ttm_prime_fd_to_handle - Get a base object handle from a prime fd
 617  *
 618  * @tfile: A struct ttm_object_file identifying the caller.
 619  * @fd: The prime / dmabuf fd.
 620  * @handle: The returned handle.
 621  *
 622  * This function returns a handle to an object that previously exported
 623  * a dma-buf. Note that we don't handle imports yet, because we simply
 624  * have no consumers of that implementation.
 625  */
 626 int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
 627                            int fd, u32 *handle)
 628 {
 629         struct ttm_object_device *tdev = tfile->tdev;
 630         struct dma_buf *dma_buf;
 631         struct ttm_prime_object *prime;
 632         struct ttm_base_object *base;
 633         int ret;
 634
 635         dma_buf = dma_buf_get(fd);
 636         if (IS_ERR(dma_buf))
 637                 return PTR_ERR(dma_buf);
 638
 639         if (dma_buf->ops != &tdev->ops)
 640                 return -ENOSYS;
 641
 642         prime = (struct ttm_prime_object *) dma_buf->priv;
 643         base = &prime->base;
 644         *handle = base->hash.key;
 645         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
 646
 647         dma_buf_put(dma_buf);
 648
 649         return ret;
 650 }
 651 EXPORT_SYMBOL_GPL(ttm_prime_fd_to_handle);
 652
 653 /**
 654  * ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
 655  *
 656  * @tfile: Struct ttm_object_file identifying the caller.
 657  * @handle: Handle to the object we're exporting from.
 658  * @flags: flags for dma-buf creation. We just pass them on.
 659  * @prime_fd: The returned file descriptor.
 660  *
 661  */
 662 int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 663                            uint32_t handle, uint32_t flags,
 664                            int *prime_fd)
 665 {
 666         struct ttm_object_device *tdev = tfile->tdev;
 667         struct ttm_base_object *base;
 668         struct dma_buf *dma_buf;
 669         struct ttm_prime_object *prime;
 670         int ret;
 671
 672         base = ttm_base_object_lookup(tfile, handle);
 673         if (unlikely(base == NULL ||
 674                      base->object_type != ttm_prime_type)) {
 675                 ret = -ENOENT;
 676                 goto out_unref;
 677         }
 678
 679         prime = container_of(base, struct ttm_prime_object, base);
 680         if (unlikely(!base->shareable)) {
 681                 ret = -EPERM;
 682                 goto out_unref;
 683         }
 684
 685         ret = mutex_lock_interruptible(&prime->mutex);
 686         if (unlikely(ret != 0)) {
 687                 ret = -ERESTARTSYS;
 688                 goto out_unref;
 689         }
 690
 691         dma_buf = prime->dma_buf;
 692         if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
 693                 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 694                 struct ttm_operation_ctx ctx = {
 695                         .interruptible = true,
 696                         .no_wait_gpu = false
 697                 };
 698                 exp_info.ops = &tdev->ops;
 699                 exp_info.size = prime->size;
 700                 exp_info.flags = flags;
 701                 exp_info.priv = prime;
 702
 703                 /*
 704                  * Need to create a new dma_buf, with memory accounting.
 705                  */
 706                 ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
 707                                            &ctx);
 708                 if (unlikely(ret != 0)) {
 709                         mutex_unlock(&prime->mutex);
 710                         goto out_unref;
 711                 }
 712
 713                 dma_buf = dma_buf_export(&exp_info);
 714                 if (IS_ERR(dma_buf)) {
 715                         ret = PTR_ERR(dma_buf);
 716                         ttm_mem_global_free(tdev->mem_glob,
 717                                             tdev->dma_buf_size);
 718                         mutex_unlock(&prime->mutex);
 719                         goto out_unref;
 720                 }
 721
 722                 /*
 723                  * dma_buf has taken the base object reference
 724                  */
 725                 base = NULL;
 726                 prime->dma_buf = dma_buf;
 727         }
 728         mutex_unlock(&prime->mutex);
 729
 730         ret = dma_buf_fd(dma_buf, flags);
 731         if (ret >= 0) {
 732                 *prime_fd = ret;
 733                 ret = 0;
 734         } else
 735                 dma_buf_put(dma_buf);
 736
 737 out_unref:
 738         if (base)
 739                 ttm_base_object_unref(&base);
 740         return ret;
 741 }
 742 EXPORT_SYMBOL_GPL(ttm_prime_handle_to_fd);
 743
 744 /**
 745  * ttm_prime_object_init - Initialize a ttm_prime_object
 746  *
 747  * @tfile: struct ttm_object_file identifying the caller
 748  * @size: The size of the dma_bufs we export.
 749  * @prime: The object to be initialized.
 750  * @shareable: See ttm_base_object_init
 751  * @type: See ttm_base_object_init
 752  * @refcount_release: See ttm_base_object_init
 753  * @ref_obj_release: See ttm_base_object_init
 754  *
 755  * Initializes an object which is compatible with the drm_prime model
 756  * for data sharing between processes and devices.
 757  */
 758 int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
 759                           struct ttm_prime_object *prime, bool shareable,
 760                           enum ttm_object_type type,
 761                           void (*refcount_release) (struct ttm_base_object **),
 762                           void (*ref_obj_release) (struct ttm_base_object *,
 763                                                    enum ttm_ref_type ref_type))
 764 {
 765         mutex_init(&prime->mutex);
 766         prime->size = PAGE_ALIGN(size);
 767         prime->real_type = type;
 768         prime->dma_buf = NULL;
 769         prime->refcount_release = refcount_release;
 770         return ttm_base_object_init(tfile, &prime->base, shareable,
 771                                     ttm_prime_type,
 772                                     ttm_prime_refcount_release,
 773                                     ref_obj_release);
 774 }
 775 EXPORT_SYMBOL(ttm_prime_object_init);