drivers/gpu/drm/drm_prime.c

   1 /*
   2  * Copyright © 2012 Red Hat
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Dave Airlie <airlied@redhat.com>
  25  *      Rob Clark <rob.clark@linaro.org>
  26  *
  27  */
  28
  29 #include <linux/export.h>
  30 #include <linux/dma-buf.h>
  31 #include <drm/drmP.h>
  32
  33 /*
  34  * DMA-BUF/GEM Object references and lifetime overview:
  35  *
  36  * On the export the dma_buf holds a reference to the exporting GEM
  37  * object. It takes this reference in handle_to_fd_ioctl, when it
  38  * first calls .prime_export and stores the exporting GEM object in
  39  * the dma_buf priv. This reference is released when the dma_buf
  40  * object goes away in the driver .release function.
  41  *
  42  * On the import the importing GEM object holds a reference to the
  43  * dma_buf (which in turn holds a ref to the exporting GEM object).
  44  * It takes that reference in the fd_to_handle ioctl.
  45  * It calls dma_buf_get, creates an attachment to it and stores the
  46  * attachment in the GEM object. When this attachment is destroyed
  47  * when the imported object is destroyed, we remove the attachment
  48  * and drop the reference to the dma_buf.
  49  *
  50  * Thus the chain of references always flows in one direction
  51  * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
  52  *
  53  * Self-importing: if userspace is using PRIME as a replacement for flink
  54  * then it will get a fd->handle request for a GEM object that it created.
  55  * Drivers should detect this situation and return back the gem object
  56  * from the dma-buf private.  Prime will do this automatically for drivers that
  57  * use the drm_gem_prime_{import,export} helpers.
  58  */
  59
  60 struct drm_prime_member {
  61         struct list_head entry;
  62         struct dma_buf *dma_buf;
  63         uint32_t handle;
  64 };
  65
  66 struct drm_prime_attachment {
  67         struct sg_table *sgt;
  68         enum dma_data_direction dir;
  69 };
  70
  71 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
  72 {
  73         struct drm_prime_member *member;
  74
  75         member = kmalloc(sizeof(*member), GFP_KERNEL);
  76         if (!member)
  77                 return -ENOMEM;
  78
  79         get_dma_buf(dma_buf);
  80         member->dma_buf = dma_buf;
  81         member->handle = handle;
  82         list_add(&member->entry, &prime_fpriv->head);
  83         return 0;
  84 }
  85
  86 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
  87                                                       uint32_t handle)
  88 {
  89         struct drm_prime_member *member;
  90
  91         list_for_each_entry(member, &prime_fpriv->head, entry) {
  92                 if (member->handle == handle)
  93                         return member->dma_buf;
  94         }
  95
  96         return NULL;
  97 }
  98
  99 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 100                                        struct dma_buf *dma_buf,
 101                                        uint32_t *handle)
 102 {
 103         struct drm_prime_member *member;
 104
 105         list_for_each_entry(member, &prime_fpriv->head, entry) {
 106                 if (member->dma_buf == dma_buf) {
 107                         *handle = member->handle;
 108                         return 0;
 109                 }
 110         }
 111         return -ENOENT;
 112 }
 113
 114 static int drm_gem_map_attach(struct dma_buf *dma_buf,
 115                               struct device *target_dev,
 116                               struct dma_buf_attachment *attach)
 117 {
 118         struct drm_prime_attachment *prime_attach;
 119         struct drm_gem_object *obj = dma_buf->priv;
 120         struct drm_device *dev = obj->dev;
 121
 122         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
 123         if (!prime_attach)
 124                 return -ENOMEM;
 125
 126         prime_attach->dir = DMA_NONE;
 127         attach->priv = prime_attach;
 128
 129         if (!dev->driver->gem_prime_pin)
 130                 return 0;
 131
 132         return dev->driver->gem_prime_pin(obj);
 133 }
 134
 135 static void drm_gem_map_detach(struct dma_buf *dma_buf,
 136                                struct dma_buf_attachment *attach)
 137 {
 138         struct drm_prime_attachment *prime_attach = attach->priv;
 139         struct drm_gem_object *obj = dma_buf->priv;
 140         struct drm_device *dev = obj->dev;
 141         struct sg_table *sgt;
 142
 143         if (dev->driver->gem_prime_unpin)
 144                 dev->driver->gem_prime_unpin(obj);
 145
 146         if (!prime_attach)
 147                 return;
 148
 149         sgt = prime_attach->sgt;
 150         if (sgt) {
 151                 if (prime_attach->dir != DMA_NONE)
 152                         dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 153                                         prime_attach->dir);
 154                 sg_free_table(sgt);
 155         }
 156
 157         kfree(sgt);
 158         kfree(prime_attach);
 159         attach->priv = NULL;
 160 }
 161
 162 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 163                                         struct dma_buf *dma_buf)
 164 {
 165         struct drm_prime_member *member, *safe;
 166
 167         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 168                 if (member->dma_buf == dma_buf) {
 169                         dma_buf_put(dma_buf);
 170                         list_del(&member->entry);
 171                         kfree(member);
 172                 }
 173         }
 174 }
 175
 176 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 177                 enum dma_data_direction dir)
 178 {
 179         struct drm_prime_attachment *prime_attach = attach->priv;
 180         struct drm_gem_object *obj = attach->dmabuf->priv;
 181         struct sg_table *sgt;
 182
 183         if (WARN_ON(dir == DMA_NONE || !prime_attach))
 184                 return ERR_PTR(-EINVAL);
 185
 186         /* return the cached mapping when possible */
 187         if (prime_attach->dir == dir)
 188                 return prime_attach->sgt;
 189
 190         /*
 191          * two mappings with different directions for the same attachment are
 192          * not allowed
 193          */
 194         if (WARN_ON(prime_attach->dir != DMA_NONE))
 195                 return ERR_PTR(-EBUSY);
 196
 197         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 198
 199         if (!IS_ERR(sgt)) {
 200                 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
 201                         sg_free_table(sgt);
 202                         kfree(sgt);
 203                         sgt = ERR_PTR(-ENOMEM);
 204                 } else {
 205                         prime_attach->sgt = sgt;
 206                         prime_attach->dir = dir;
 207                 }
 208         }
 209
 210         return sgt;
 211 }
 212
 213 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 214                 struct sg_table *sgt, enum dma_data_direction dir)
 215 {
 216         /* nothing to be done here */
 217 }
 218
 219 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 220 {
 221         struct drm_gem_object *obj = dma_buf->priv;
 222
 223         /* drop the reference on the export fd holds */
 224         drm_gem_object_unreference_unlocked(obj);
 225 }
 226 EXPORT_SYMBOL(drm_gem_dmabuf_release);
 227
 228 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 229 {
 230         struct drm_gem_object *obj = dma_buf->priv;
 231         struct drm_device *dev = obj->dev;
 232
 233         return dev->driver->gem_prime_vmap(obj);
 234 }
 235
 236 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 237 {
 238         struct drm_gem_object *obj = dma_buf->priv;
 239         struct drm_device *dev = obj->dev;
 240
 241         dev->driver->gem_prime_vunmap(obj, vaddr);
 242 }
 243
 244 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 245                 unsigned long page_num)
 246 {
 247         return NULL;
 248 }
 249
 250 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 251                 unsigned long page_num, void *addr)
 252 {
 253
 254 }
 255 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 256                 unsigned long page_num)
 257 {
 258         return NULL;
 259 }
 260
 261 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 262                 unsigned long page_num, void *addr)
 263 {
 264
 265 }
 266
 267 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 268                 struct vm_area_struct *vma)
 269 {
 270         struct drm_gem_object *obj = dma_buf->priv;
 271         struct drm_device *dev = obj->dev;
 272
 273         if (!dev->driver->gem_prime_mmap)
 274                 return -ENOSYS;
 275
 276         return dev->driver->gem_prime_mmap(obj, vma);
 277 }
 278
 279 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 280         .attach = drm_gem_map_attach,
 281         .detach = drm_gem_map_detach,
 282         .map_dma_buf = drm_gem_map_dma_buf,
 283         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 284         .release = drm_gem_dmabuf_release,
 285         .kmap = drm_gem_dmabuf_kmap,
 286         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 287         .kunmap = drm_gem_dmabuf_kunmap,
 288         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 289         .mmap = drm_gem_dmabuf_mmap,
 290         .vmap = drm_gem_dmabuf_vmap,
 291         .vunmap = drm_gem_dmabuf_vunmap,
 292 };
 293
 294 /**
 295  * DOC: PRIME Helpers
 296  *
 297  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 298  * simpler APIs by using the helper functions @drm_gem_prime_export and
 299  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 300  * five lower-level driver callbacks:
 301  *
 302  * Export callbacks:
 303  *
 304  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 305  *
 306  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 307  *
 308  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 309  *
 310  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 311  *
 312  * Import callback:
 313  *
 314  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 315  *    driver's scatter/gather table
 316  */
 317
 318 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 319                                      struct drm_gem_object *obj, int flags)
 320 {
 321         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
 322 }
 323 EXPORT_SYMBOL(drm_gem_prime_export);
 324
 325 static struct dma_buf *export_and_register_object(struct drm_device *dev,
 326                                                   struct drm_gem_object *obj,
 327                                                   uint32_t flags)
 328 {
 329         struct dma_buf *dmabuf;
 330
 331         /* prevent races with concurrent gem_close. */
 332         if (obj->handle_count == 0) {
 333                 dmabuf = ERR_PTR(-ENOENT);
 334                 return dmabuf;
 335         }
 336
 337         dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
 338         if (IS_ERR(dmabuf)) {
 339                 /* normally the created dma-buf takes ownership of the ref,
 340                  * but if that fails then drop the ref
 341                  */
 342                 return dmabuf;
 343         }
 344
 345         /*
 346          * Note that callers do not need to clean up the export cache
 347          * since the check for obj->handle_count guarantees that someone
 348          * will clean it up.
 349          */
 350         obj->dma_buf = dmabuf;
 351         get_dma_buf(obj->dma_buf);
 352         /* Grab a new ref since the callers is now used by the dma-buf */
 353         drm_gem_object_reference(obj);
 354
 355         return dmabuf;
 356 }
 357
 358 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 359                 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
 360                 int *prime_fd)
 361 {
 362         struct drm_gem_object *obj;
 363         int ret = 0;
 364         struct dma_buf *dmabuf;
 365
 366         mutex_lock(&file_priv->prime.lock);
 367         obj = drm_gem_object_lookup(dev, file_priv, handle);
 368         if (!obj)  {
 369                 ret = -ENOENT;
 370                 goto out_unlock;
 371         }
 372
 373         dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
 374         if (dmabuf) {
 375                 get_dma_buf(dmabuf);
 376                 goto out_have_handle;
 377         }
 378
 379         mutex_lock(&dev->object_name_lock);
 380         /* re-export the original imported object */
 381         if (obj->import_attach) {
 382                 dmabuf = obj->import_attach->dmabuf;
 383                 get_dma_buf(dmabuf);
 384                 goto out_have_obj;
 385         }
 386
 387         if (obj->dma_buf) {
 388                 get_dma_buf(obj->dma_buf);
 389                 dmabuf = obj->dma_buf;
 390                 goto out_have_obj;
 391         }
 392
 393         dmabuf = export_and_register_object(dev, obj, flags);
 394         if (IS_ERR(dmabuf)) {
 395                 /* normally the created dma-buf takes ownership of the ref,
 396                  * but if that fails then drop the ref
 397                  */
 398                 ret = PTR_ERR(dmabuf);
 399                 mutex_unlock(&dev->object_name_lock);
 400                 goto out;
 401         }
 402
 403 out_have_obj:
 404         /*
 405          * If we've exported this buffer then cheat and add it to the import list
 406          * so we get the correct handle back. We must do this under the
 407          * protection of dev->object_name_lock to ensure that a racing gem close
 408          * ioctl doesn't miss to remove this buffer handle from the cache.
 409          */
 410         ret = drm_prime_add_buf_handle(&file_priv->prime,
 411                                        dmabuf, handle);
 412         mutex_unlock(&dev->object_name_lock);
 413         if (ret)
 414                 goto fail_put_dmabuf;
 415
 416 out_have_handle:
 417         ret = dma_buf_fd(dmabuf, flags);
 418         /*
 419          * We must _not_ remove the buffer from the handle cache since the newly
 420          * created dma buf is already linked in the global obj->dma_buf pointer,
 421          * and that is invariant as long as a userspace gem handle exists.
 422          * Closing the handle will clean out the cache anyway, so we don't leak.
 423          */
 424         if (ret < 0) {
 425                 goto fail_put_dmabuf;
 426         } else {
 427                 *prime_fd = ret;
 428                 ret = 0;
 429         }
 430
 431         goto out;
 432
 433 fail_put_dmabuf:
 434         dma_buf_put(dmabuf);
 435 out:
 436         drm_gem_object_unreference_unlocked(obj);
 437 out_unlock:
 438         mutex_unlock(&file_priv->prime.lock);
 439
 440         return ret;
 441 }
 442 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 443
 444 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 445                                             struct dma_buf *dma_buf)
 446 {
 447         struct dma_buf_attachment *attach;
 448         struct sg_table *sgt;
 449         struct drm_gem_object *obj;
 450         int ret;
 451
 452         if (!dev->driver->gem_prime_import_sg_table)
 453                 return ERR_PTR(-EINVAL);
 454
 455         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 456                 obj = dma_buf->priv;
 457                 if (obj->dev == dev) {
 458                         /*
 459                          * Importing dmabuf exported from out own gem increases
 460                          * refcount on gem itself instead of f_count of dmabuf.
 461                          */
 462                         drm_gem_object_reference(obj);
 463                         return obj;
 464                 }
 465         }
 466
 467         attach = dma_buf_attach(dma_buf, dev->dev);
 468         if (IS_ERR(attach))
 469                 return ERR_CAST(attach);
 470
 471         get_dma_buf(dma_buf);
 472
 473         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 474         if (IS_ERR_OR_NULL(sgt)) {
 475                 ret = PTR_ERR(sgt);
 476                 goto fail_detach;
 477         }
 478
 479         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 480         if (IS_ERR(obj)) {
 481                 ret = PTR_ERR(obj);
 482                 goto fail_unmap;
 483         }
 484
 485         obj->import_attach = attach;
 486
 487         return obj;
 488
 489 fail_unmap:
 490         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 491 fail_detach:
 492         dma_buf_detach(dma_buf, attach);
 493         dma_buf_put(dma_buf);
 494
 495         return ERR_PTR(ret);
 496 }
 497 EXPORT_SYMBOL(drm_gem_prime_import);
 498
 499 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 500                 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
 501 {
 502         struct dma_buf *dma_buf;
 503         struct drm_gem_object *obj;
 504         int ret;
 505
 506         dma_buf = dma_buf_get(prime_fd);
 507         if (IS_ERR(dma_buf))
 508                 return PTR_ERR(dma_buf);
 509
 510         mutex_lock(&file_priv->prime.lock);
 511
 512         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 513                         dma_buf, handle);
 514         if (ret == 0)
 515                 goto out_put;
 516
 517         /* never seen this one, need to import */
 518         mutex_lock(&dev->object_name_lock);
 519         obj = dev->driver->gem_prime_import(dev, dma_buf);
 520         if (IS_ERR(obj)) {
 521                 ret = PTR_ERR(obj);
 522                 goto out_unlock;
 523         }
 524
 525         if (obj->dma_buf) {
 526                 WARN_ON(obj->dma_buf != dma_buf);
 527         } else {
 528                 obj->dma_buf = dma_buf;
 529                 get_dma_buf(dma_buf);
 530         }
 531
 532         /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
 533         ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 534         drm_gem_object_unreference_unlocked(obj);
 535         if (ret)
 536                 goto out_put;
 537
 538         ret = drm_prime_add_buf_handle(&file_priv->prime,
 539                         dma_buf, *handle);
 540         if (ret)
 541                 goto fail;
 542
 543         mutex_unlock(&file_priv->prime.lock);
 544
 545         dma_buf_put(dma_buf);
 546
 547         return 0;
 548
 549 fail:
 550         /* hmm, if driver attached, we are relying on the free-object path
 551          * to detach.. which seems ok..
 552          */
 553         drm_gem_handle_delete(file_priv, *handle);
 554 out_unlock:
 555         mutex_unlock(&dev->object_name_lock);
 556 out_put:
 557         dma_buf_put(dma_buf);
 558         mutex_unlock(&file_priv->prime.lock);
 559         return ret;
 560 }
 561 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 562
 563 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 564                                  struct drm_file *file_priv)
 565 {
 566         struct drm_prime_handle *args = data;
 567         uint32_t flags;
 568
 569         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 570                 return -EINVAL;
 571
 572         if (!dev->driver->prime_handle_to_fd)
 573                 return -ENOSYS;
 574
 575         /* check flags are valid */
 576         if (args->flags & ~DRM_CLOEXEC)
 577                 return -EINVAL;
 578
 579         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 580         flags = args->flags & DRM_CLOEXEC;
 581
 582         return dev->driver->prime_handle_to_fd(dev, file_priv,
 583                         args->handle, flags, &args->fd);
 584 }
 585
 586 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 587                                  struct drm_file *file_priv)
 588 {
 589         struct drm_prime_handle *args = data;
 590
 591         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 592                 return -EINVAL;
 593
 594         if (!dev->driver->prime_fd_to_handle)
 595                 return -ENOSYS;
 596
 597         return dev->driver->prime_fd_to_handle(dev, file_priv,
 598                         args->fd, &args->handle);
 599 }
 600
 601 /*
 602  * drm_prime_pages_to_sg
 603  *
 604  * this helper creates an sg table object from a set of pages
 605  * the driver is responsible for mapping the pages into the
 606  * importers address space
 607  */
 608 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 609 {
 610         struct sg_table *sg = NULL;
 611         int ret;
 612
 613         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 614         if (!sg) {
 615                 ret = -ENOMEM;
 616                 goto out;
 617         }
 618
 619         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 620                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 621         if (ret)
 622                 goto out;
 623
 624         return sg;
 625 out:
 626         kfree(sg);
 627         return ERR_PTR(ret);
 628 }
 629 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 630
 631 /* export an sg table into an array of pages and addresses
 632    this is currently required by the TTM driver in order to do correct fault
 633    handling */
 634 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 635                                      dma_addr_t *addrs, int max_pages)
 636 {
 637         unsigned count;
 638         struct scatterlist *sg;
 639         struct page *page;
 640         u32 len;
 641         int pg_index;
 642         dma_addr_t addr;
 643
 644         pg_index = 0;
 645         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 646                 len = sg->length;
 647                 page = sg_page(sg);
 648                 addr = sg_dma_address(sg);
 649
 650                 while (len > 0) {
 651                         if (WARN_ON(pg_index >= max_pages))
 652                                 return -1;
 653                         pages[pg_index] = page;
 654                         if (addrs)
 655                                 addrs[pg_index] = addr;
 656
 657                         page++;
 658                         addr += PAGE_SIZE;
 659                         len -= PAGE_SIZE;
 660                         pg_index++;
 661                 }
 662         }
 663         return 0;
 664 }
 665 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 666 /* helper function to cleanup a GEM/prime object */
 667 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 668 {
 669         struct dma_buf_attachment *attach;
 670         struct dma_buf *dma_buf;
 671         attach = obj->import_attach;
 672         if (sg)
 673                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 674         dma_buf = attach->dmabuf;
 675         dma_buf_detach(attach->dmabuf, attach);
 676         /* remove the reference */
 677         dma_buf_put(dma_buf);
 678 }
 679 EXPORT_SYMBOL(drm_prime_gem_destroy);
 680
 681 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 682 {
 683         INIT_LIST_HEAD(&prime_fpriv->head);
 684         mutex_init(&prime_fpriv->lock);
 685 }
 686 EXPORT_SYMBOL(drm_prime_init_file_private);
 687
 688 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 689 {
 690         /* by now drm_gem_release should've made sure the list is empty */
 691         WARN_ON(!list_empty(&prime_fpriv->head));
 692 }
 693 EXPORT_SYMBOL(drm_prime_destroy_file_private);