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,
  72                                     struct dma_buf *dma_buf, uint32_t handle)
  73 {
  74         struct drm_prime_member *member;
  75
  76         member = kmalloc(sizeof(*member), GFP_KERNEL);
  77         if (!member)
  78                 return -ENOMEM;
  79
  80         get_dma_buf(dma_buf);
  81         member->dma_buf = dma_buf;
  82         member->handle = handle;
  83         list_add(&member->entry, &prime_fpriv->head);
  84         return 0;
  85 }
  86
  87 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
  88                                                       uint32_t handle)
  89 {
  90         struct drm_prime_member *member;
  91
  92         list_for_each_entry(member, &prime_fpriv->head, entry) {
  93                 if (member->handle == handle)
  94                         return member->dma_buf;
  95         }
  96
  97         return NULL;
  98 }
  99
 100 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 101                                        struct dma_buf *dma_buf,
 102                                        uint32_t *handle)
 103 {
 104         struct drm_prime_member *member;
 105
 106         list_for_each_entry(member, &prime_fpriv->head, entry) {
 107                 if (member->dma_buf == dma_buf) {
 108                         *handle = member->handle;
 109                         return 0;
 110                 }
 111         }
 112         return -ENOENT;
 113 }
 114
 115 static int drm_gem_map_attach(struct dma_buf *dma_buf,
 116                               struct device *target_dev,
 117                               struct dma_buf_attachment *attach)
 118 {
 119         struct drm_prime_attachment *prime_attach;
 120         struct drm_gem_object *obj = dma_buf->priv;
 121         struct drm_device *dev = obj->dev;
 122
 123         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
 124         if (!prime_attach)
 125                 return -ENOMEM;
 126
 127         prime_attach->dir = DMA_NONE;
 128         attach->priv = prime_attach;
 129
 130         if (!dev->driver->gem_prime_pin)
 131                 return 0;
 132
 133         return dev->driver->gem_prime_pin(obj);
 134 }
 135
 136 static void drm_gem_map_detach(struct dma_buf *dma_buf,
 137                                struct dma_buf_attachment *attach)
 138 {
 139         struct drm_prime_attachment *prime_attach = attach->priv;
 140         struct drm_gem_object *obj = dma_buf->priv;
 141         struct drm_device *dev = obj->dev;
 142         struct sg_table *sgt;
 143
 144         if (dev->driver->gem_prime_unpin)
 145                 dev->driver->gem_prime_unpin(obj);
 146
 147         if (!prime_attach)
 148                 return;
 149
 150         sgt = prime_attach->sgt;
 151         if (sgt) {
 152                 if (prime_attach->dir != DMA_NONE)
 153                         dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 154                                         prime_attach->dir);
 155                 sg_free_table(sgt);
 156         }
 157
 158         kfree(sgt);
 159         kfree(prime_attach);
 160         attach->priv = NULL;
 161 }
 162
 163 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 164                                         struct dma_buf *dma_buf)
 165 {
 166         struct drm_prime_member *member, *safe;
 167
 168         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 169                 if (member->dma_buf == dma_buf) {
 170                         dma_buf_put(dma_buf);
 171                         list_del(&member->entry);
 172                         kfree(member);
 173                 }
 174         }
 175 }
 176
 177 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 178                                             enum dma_data_direction dir)
 179 {
 180         struct drm_prime_attachment *prime_attach = attach->priv;
 181         struct drm_gem_object *obj = attach->dmabuf->priv;
 182         struct sg_table *sgt;
 183
 184         if (WARN_ON(dir == DMA_NONE || !prime_attach))
 185                 return ERR_PTR(-EINVAL);
 186
 187         /* return the cached mapping when possible */
 188         if (prime_attach->dir == dir)
 189                 return prime_attach->sgt;
 190
 191         /*
 192          * two mappings with different directions for the same attachment are
 193          * not allowed
 194          */
 195         if (WARN_ON(prime_attach->dir != DMA_NONE))
 196                 return ERR_PTR(-EBUSY);
 197
 198         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 199
 200         if (!IS_ERR(sgt)) {
 201                 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
 202                         sg_free_table(sgt);
 203                         kfree(sgt);
 204                         sgt = ERR_PTR(-ENOMEM);
 205                 } else {
 206                         prime_attach->sgt = sgt;
 207                         prime_attach->dir = dir;
 208                 }
 209         }
 210
 211         return sgt;
 212 }
 213
 214 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 215                                   struct sg_table *sgt,
 216                                   enum dma_data_direction dir)
 217 {
 218         /* nothing to be done here */
 219 }
 220
 221 /**
 222  * drm_gem_dmabuf_release - dma_buf release implementation for GEM
 223  * @dma_buf: buffer to be released
 224  *
 225  * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
 226  * must use this in their dma_buf ops structure as the release callback.
 227  */
 228 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 229 {
 230         struct drm_gem_object *obj = dma_buf->priv;
 231
 232         /* drop the reference on the export fd holds */
 233         drm_gem_object_unreference_unlocked(obj);
 234 }
 235 EXPORT_SYMBOL(drm_gem_dmabuf_release);
 236
 237 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 238 {
 239         struct drm_gem_object *obj = dma_buf->priv;
 240         struct drm_device *dev = obj->dev;
 241
 242         return dev->driver->gem_prime_vmap(obj);
 243 }
 244
 245 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 246 {
 247         struct drm_gem_object *obj = dma_buf->priv;
 248         struct drm_device *dev = obj->dev;
 249
 250         dev->driver->gem_prime_vunmap(obj, vaddr);
 251 }
 252
 253 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 254                                         unsigned long page_num)
 255 {
 256         return NULL;
 257 }
 258
 259 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 260                                          unsigned long page_num, void *addr)
 261 {
 262
 263 }
 264 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 265                                  unsigned long page_num)
 266 {
 267         return NULL;
 268 }
 269
 270 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 271                                   unsigned long page_num, void *addr)
 272 {
 273
 274 }
 275
 276 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 277                                struct vm_area_struct *vma)
 278 {
 279         struct drm_gem_object *obj = dma_buf->priv;
 280         struct drm_device *dev = obj->dev;
 281
 282         if (!dev->driver->gem_prime_mmap)
 283                 return -ENOSYS;
 284
 285         return dev->driver->gem_prime_mmap(obj, vma);
 286 }
 287
 288 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 289         .attach = drm_gem_map_attach,
 290         .detach = drm_gem_map_detach,
 291         .map_dma_buf = drm_gem_map_dma_buf,
 292         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 293         .release = drm_gem_dmabuf_release,
 294         .kmap = drm_gem_dmabuf_kmap,
 295         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 296         .kunmap = drm_gem_dmabuf_kunmap,
 297         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 298         .mmap = drm_gem_dmabuf_mmap,
 299         .vmap = drm_gem_dmabuf_vmap,
 300         .vunmap = drm_gem_dmabuf_vunmap,
 301 };
 302
 303 /**
 304  * DOC: PRIME Helpers
 305  *
 306  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 307  * simpler APIs by using the helper functions @drm_gem_prime_export and
 308  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 309  * five lower-level driver callbacks:
 310  *
 311  * Export callbacks:
 312  *
 313  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 314  *
 315  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 316  *
 317  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 318  *
 319  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 320  *
 321  * Import callback:
 322  *
 323  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 324  *    driver's scatter/gather table
 325  */
 326
 327 /**
 328  * drm_gem_prime_export - helper library implemention of the export callback
 329  * @dev: drm_device to export from
 330  * @obj: GEM object to export
 331  * @flags: flags like DRM_CLOEXEC
 332  *
 333  * This is the implementation of the gem_prime_export functions for GEM drivers
 334  * using the PRIME helpers.
 335  */
 336 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 337                                      struct drm_gem_object *obj, int flags)
 338 {
 339         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
 340 }
 341 EXPORT_SYMBOL(drm_gem_prime_export);
 342
 343 static struct dma_buf *export_and_register_object(struct drm_device *dev,
 344                                                   struct drm_gem_object *obj,
 345                                                   uint32_t flags)
 346 {
 347         struct dma_buf *dmabuf;
 348
 349         /* prevent races with concurrent gem_close. */
 350         if (obj->handle_count == 0) {
 351                 dmabuf = ERR_PTR(-ENOENT);
 352                 return dmabuf;
 353         }
 354
 355         dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
 356         if (IS_ERR(dmabuf)) {
 357                 /* normally the created dma-buf takes ownership of the ref,
 358                  * but if that fails then drop the ref
 359                  */
 360                 return dmabuf;
 361         }
 362
 363         /*
 364          * Note that callers do not need to clean up the export cache
 365          * since the check for obj->handle_count guarantees that someone
 366          * will clean it up.
 367          */
 368         obj->dma_buf = dmabuf;
 369         get_dma_buf(obj->dma_buf);
 370         /* Grab a new ref since the callers is now used by the dma-buf */
 371         drm_gem_object_reference(obj);
 372
 373         return dmabuf;
 374 }
 375
 376 /**
 377  * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
 378  * @dev: dev to export the buffer from
 379  * @file_priv: drm file-private structure
 380  * @handle: buffer handle to export
 381  * @flags: flags like DRM_CLOEXEC
 382  * @prime_fd: pointer to storage for the fd id of the create dma-buf
 383  *
 384  * This is the PRIME export function which must be used mandatorily by GEM
 385  * drivers to ensure correct lifetime management of the underlying GEM object.
 386  * The actual exporting from GEM object to a dma-buf is done through the
 387  * gem_prime_export driver callback.
 388  */
 389 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 390                                struct drm_file *file_priv, uint32_t handle,
 391                                uint32_t flags,
 392                                int *prime_fd)
 393 {
 394         struct drm_gem_object *obj;
 395         int ret = 0;
 396         struct dma_buf *dmabuf;
 397
 398         mutex_lock(&file_priv->prime.lock);
 399         obj = drm_gem_object_lookup(dev, file_priv, handle);
 400         if (!obj)  {
 401                 ret = -ENOENT;
 402                 goto out_unlock;
 403         }
 404
 405         dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
 406         if (dmabuf) {
 407                 get_dma_buf(dmabuf);
 408                 goto out_have_handle;
 409         }
 410
 411         mutex_lock(&dev->object_name_lock);
 412         /* re-export the original imported object */
 413         if (obj->import_attach) {
 414                 dmabuf = obj->import_attach->dmabuf;
 415                 get_dma_buf(dmabuf);
 416                 goto out_have_obj;
 417         }
 418
 419         if (obj->dma_buf) {
 420                 get_dma_buf(obj->dma_buf);
 421                 dmabuf = obj->dma_buf;
 422                 goto out_have_obj;
 423         }
 424
 425         dmabuf = export_and_register_object(dev, obj, flags);
 426         if (IS_ERR(dmabuf)) {
 427                 /* normally the created dma-buf takes ownership of the ref,
 428                  * but if that fails then drop the ref
 429                  */
 430                 ret = PTR_ERR(dmabuf);
 431                 mutex_unlock(&dev->object_name_lock);
 432                 goto out;
 433         }
 434
 435 out_have_obj:
 436         /*
 437          * If we've exported this buffer then cheat and add it to the import list
 438          * so we get the correct handle back. We must do this under the
 439          * protection of dev->object_name_lock to ensure that a racing gem close
 440          * ioctl doesn't miss to remove this buffer handle from the cache.
 441          */
 442         ret = drm_prime_add_buf_handle(&file_priv->prime,
 443                                        dmabuf, handle);
 444         mutex_unlock(&dev->object_name_lock);
 445         if (ret)
 446                 goto fail_put_dmabuf;
 447
 448 out_have_handle:
 449         ret = dma_buf_fd(dmabuf, flags);
 450         /*
 451          * We must _not_ remove the buffer from the handle cache since the newly
 452          * created dma buf is already linked in the global obj->dma_buf pointer,
 453          * and that is invariant as long as a userspace gem handle exists.
 454          * Closing the handle will clean out the cache anyway, so we don't leak.
 455          */
 456         if (ret < 0) {
 457                 goto fail_put_dmabuf;
 458         } else {
 459                 *prime_fd = ret;
 460                 ret = 0;
 461         }
 462
 463         goto out;
 464
 465 fail_put_dmabuf:
 466         dma_buf_put(dmabuf);
 467 out:
 468         drm_gem_object_unreference_unlocked(obj);
 469 out_unlock:
 470         mutex_unlock(&file_priv->prime.lock);
 471
 472         return ret;
 473 }
 474 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 475
 476 /**
 477  * drm_gem_prime_import - helper library implemention of the import callback
 478  * @dev: drm_device to import into
 479  * @dma_buf: dma-buf object to import
 480  *
 481  * This is the implementation of the gem_prime_import functions for GEM drivers
 482  * using the PRIME helpers.
 483  */
 484 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 485                                             struct dma_buf *dma_buf)
 486 {
 487         struct dma_buf_attachment *attach;
 488         struct sg_table *sgt;
 489         struct drm_gem_object *obj;
 490         int ret;
 491
 492         if (!dev->driver->gem_prime_import_sg_table)
 493                 return ERR_PTR(-EINVAL);
 494
 495         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 496                 obj = dma_buf->priv;
 497                 if (obj->dev == dev) {
 498                         /*
 499                          * Importing dmabuf exported from out own gem increases
 500                          * refcount on gem itself instead of f_count of dmabuf.
 501                          */
 502                         drm_gem_object_reference(obj);
 503                         return obj;
 504                 }
 505         }
 506
 507         attach = dma_buf_attach(dma_buf, dev->dev);
 508         if (IS_ERR(attach))
 509                 return ERR_CAST(attach);
 510
 511         get_dma_buf(dma_buf);
 512
 513         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 514         if (IS_ERR_OR_NULL(sgt)) {
 515                 ret = PTR_ERR(sgt);
 516                 goto fail_detach;
 517         }
 518
 519         obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
 520         if (IS_ERR(obj)) {
 521                 ret = PTR_ERR(obj);
 522                 goto fail_unmap;
 523         }
 524
 525         obj->import_attach = attach;
 526
 527         return obj;
 528
 529 fail_unmap:
 530         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 531 fail_detach:
 532         dma_buf_detach(dma_buf, attach);
 533         dma_buf_put(dma_buf);
 534
 535         return ERR_PTR(ret);
 536 }
 537 EXPORT_SYMBOL(drm_gem_prime_import);
 538
 539 /**
 540  * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
 541  * @dev: dev to export the buffer from
 542  * @file_priv: drm file-private structure
 543  * @prime_fd: fd id of the dma-buf which should be imported
 544  * @handle: pointer to storage for the handle of the imported buffer object
 545  *
 546  * This is the PRIME import function which must be used mandatorily by GEM
 547  * drivers to ensure correct lifetime management of the underlying GEM object.
 548  * The actual importing of GEM object from the dma-buf is done through the
 549  * gem_import_export driver callback.
 550  */
 551 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 552                                struct drm_file *file_priv, int prime_fd,
 553                                uint32_t *handle)
 554 {
 555         struct dma_buf *dma_buf;
 556         struct drm_gem_object *obj;
 557         int ret;
 558
 559         dma_buf = dma_buf_get(prime_fd);
 560         if (IS_ERR(dma_buf))
 561                 return PTR_ERR(dma_buf);
 562
 563         mutex_lock(&file_priv->prime.lock);
 564
 565         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 566                         dma_buf, handle);
 567         if (ret == 0)
 568                 goto out_put;
 569
 570         /* never seen this one, need to import */
 571         mutex_lock(&dev->object_name_lock);
 572         obj = dev->driver->gem_prime_import(dev, dma_buf);
 573         if (IS_ERR(obj)) {
 574                 ret = PTR_ERR(obj);
 575                 goto out_unlock;
 576         }
 577
 578         if (obj->dma_buf) {
 579                 WARN_ON(obj->dma_buf != dma_buf);
 580         } else {
 581                 obj->dma_buf = dma_buf;
 582                 get_dma_buf(dma_buf);
 583         }
 584
 585         /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
 586         ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 587         drm_gem_object_unreference_unlocked(obj);
 588         if (ret)
 589                 goto out_put;
 590
 591         ret = drm_prime_add_buf_handle(&file_priv->prime,
 592                         dma_buf, *handle);
 593         if (ret)
 594                 goto fail;
 595
 596         mutex_unlock(&file_priv->prime.lock);
 597
 598         dma_buf_put(dma_buf);
 599
 600         return 0;
 601
 602 fail:
 603         /* hmm, if driver attached, we are relying on the free-object path
 604          * to detach.. which seems ok..
 605          */
 606         drm_gem_handle_delete(file_priv, *handle);
 607 out_unlock:
 608         mutex_unlock(&dev->object_name_lock);
 609 out_put:
 610         dma_buf_put(dma_buf);
 611         mutex_unlock(&file_priv->prime.lock);
 612         return ret;
 613 }
 614 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 615
 616 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 617                                  struct drm_file *file_priv)
 618 {
 619         struct drm_prime_handle *args = data;
 620         uint32_t flags;
 621
 622         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 623                 return -EINVAL;
 624
 625         if (!dev->driver->prime_handle_to_fd)
 626                 return -ENOSYS;
 627
 628         /* check flags are valid */
 629         if (args->flags & ~DRM_CLOEXEC)
 630                 return -EINVAL;
 631
 632         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 633         flags = args->flags & DRM_CLOEXEC;
 634
 635         return dev->driver->prime_handle_to_fd(dev, file_priv,
 636                         args->handle, flags, &args->fd);
 637 }
 638
 639 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 640                                  struct drm_file *file_priv)
 641 {
 642         struct drm_prime_handle *args = data;
 643
 644         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 645                 return -EINVAL;
 646
 647         if (!dev->driver->prime_fd_to_handle)
 648                 return -ENOSYS;
 649
 650         return dev->driver->prime_fd_to_handle(dev, file_priv,
 651                         args->fd, &args->handle);
 652 }
 653
 654 /**
 655  * drm_prime_pages_to_sg - converts a page array into an sg list
 656  * @pages: pointer to the array of page pointers to convert
 657  * @nr_pages: length of the page vector
 658  *
 659  * This helper creates an sg table object from a set of pages
 660  * the driver is responsible for mapping the pages into the
 661  * importers address space for use with dma_buf itself.
 662  */
 663 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
 664 {
 665         struct sg_table *sg = NULL;
 666         int ret;
 667
 668         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 669         if (!sg) {
 670                 ret = -ENOMEM;
 671                 goto out;
 672         }
 673
 674         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 675                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 676         if (ret)
 677                 goto out;
 678
 679         return sg;
 680 out:
 681         kfree(sg);
 682         return ERR_PTR(ret);
 683 }
 684 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 685
 686 /**
 687  * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
 688  * @sgt: scatter-gather table to convert
 689  * @pages: array of page pointers to store the page array in
 690  * @addrs: optional array to store the dma bus address of each page
 691  * @max_pages: size of both the passed-in arrays
 692  *
 693  * Exports an sg table into an array of pages and addresses. This is currently
 694  * required by the TTM driver in order to do correct fault handling.
 695  */
 696 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 697                                      dma_addr_t *addrs, int max_pages)
 698 {
 699         unsigned count;
 700         struct scatterlist *sg;
 701         struct page *page;
 702         u32 len;
 703         int pg_index;
 704         dma_addr_t addr;
 705
 706         pg_index = 0;
 707         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 708                 len = sg->length;
 709                 page = sg_page(sg);
 710                 addr = sg_dma_address(sg);
 711
 712                 while (len > 0) {
 713                         if (WARN_ON(pg_index >= max_pages))
 714                                 return -1;
 715                         pages[pg_index] = page;
 716                         if (addrs)
 717                                 addrs[pg_index] = addr;
 718
 719                         page++;
 720                         addr += PAGE_SIZE;
 721                         len -= PAGE_SIZE;
 722                         pg_index++;
 723                 }
 724         }
 725         return 0;
 726 }
 727 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 728
 729 /**
 730  * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
 731  * @obj: GEM object which was created from a dma-buf
 732  * @sg: the sg-table which was pinned at import time
 733  *
 734  * This is the cleanup functions which GEM drivers need to call when they use
 735  * @drm_gem_prime_import to import dma-bufs.
 736  */
 737 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 738 {
 739         struct dma_buf_attachment *attach;
 740         struct dma_buf *dma_buf;
 741         attach = obj->import_attach;
 742         if (sg)
 743                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 744         dma_buf = attach->dmabuf;
 745         dma_buf_detach(attach->dmabuf, attach);
 746         /* remove the reference */
 747         dma_buf_put(dma_buf);
 748 }
 749 EXPORT_SYMBOL(drm_prime_gem_destroy);
 750
 751 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 752 {
 753         INIT_LIST_HEAD(&prime_fpriv->head);
 754         mutex_init(&prime_fpriv->lock);
 755 }
 756
 757 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 758 {
 759         /* by now drm_gem_release should've made sure the list is empty */
 760         WARN_ON(!list_empty(&prime_fpriv->head));
 761 }