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 #include <drm/drm_gem.h>
  33
  34 #include "drm_internal.h"
  35
  36 /*
  37  * DMA-BUF/GEM Object references and lifetime overview:
  38  *
  39  * On the export the dma_buf holds a reference to the exporting GEM
  40  * object. It takes this reference in handle_to_fd_ioctl, when it
  41  * first calls .prime_export and stores the exporting GEM object in
  42  * the dma_buf priv. This reference is released when the dma_buf
  43  * object goes away in the driver .release function.
  44  *
  45  * On the import the importing GEM object holds a reference to the
  46  * dma_buf (which in turn holds a ref to the exporting GEM object).
  47  * It takes that reference in the fd_to_handle ioctl.
  48  * It calls dma_buf_get, creates an attachment to it and stores the
  49  * attachment in the GEM object. When this attachment is destroyed
  50  * when the imported object is destroyed, we remove the attachment
  51  * and drop the reference to the dma_buf.
  52  *
  53  * Thus the chain of references always flows in one direction
  54  * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
  55  *
  56  * Self-importing: if userspace is using PRIME as a replacement for flink
  57  * then it will get a fd->handle request for a GEM object that it created.
  58  * Drivers should detect this situation and return back the gem object
  59  * from the dma-buf private.  Prime will do this automatically for drivers that
  60  * use the drm_gem_prime_{import,export} helpers.
  61  */
  62
  63 struct drm_prime_member {
  64         struct list_head entry;
  65         struct dma_buf *dma_buf;
  66         uint32_t handle;
  67 };
  68
  69 struct drm_prime_attachment {
  70         struct sg_table *sgt;
  71         enum dma_data_direction dir;
  72 };
  73
  74 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
  75                                     struct dma_buf *dma_buf, uint32_t handle)
  76 {
  77         struct drm_prime_member *member;
  78
  79         member = kmalloc(sizeof(*member), GFP_KERNEL);
  80         if (!member)
  81                 return -ENOMEM;
  82
  83         get_dma_buf(dma_buf);
  84         member->dma_buf = dma_buf;
  85         member->handle = handle;
  86         list_add(&member->entry, &prime_fpriv->head);
  87         return 0;
  88 }
  89
  90 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
  91                                                       uint32_t handle)
  92 {
  93         struct drm_prime_member *member;
  94
  95         list_for_each_entry(member, &prime_fpriv->head, entry) {
  96                 if (member->handle == handle)
  97                         return member->dma_buf;
  98         }
  99
 100         return NULL;
 101 }
 102
 103 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 104                                        struct dma_buf *dma_buf,
 105                                        uint32_t *handle)
 106 {
 107         struct drm_prime_member *member;
 108
 109         list_for_each_entry(member, &prime_fpriv->head, entry) {
 110                 if (member->dma_buf == dma_buf) {
 111                         *handle = member->handle;
 112                         return 0;
 113                 }
 114         }
 115         return -ENOENT;
 116 }
 117
 118 static int drm_gem_map_attach(struct dma_buf *dma_buf,
 119                               struct device *target_dev,
 120                               struct dma_buf_attachment *attach)
 121 {
 122         struct drm_prime_attachment *prime_attach;
 123         struct drm_gem_object *obj = dma_buf->priv;
 124         struct drm_device *dev = obj->dev;
 125
 126         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
 127         if (!prime_attach)
 128                 return -ENOMEM;
 129
 130         prime_attach->dir = DMA_NONE;
 131         attach->priv = prime_attach;
 132
 133         if (!dev->driver->gem_prime_pin)
 134                 return 0;
 135
 136         return dev->driver->gem_prime_pin(obj);
 137 }
 138
 139 static void drm_gem_map_detach(struct dma_buf *dma_buf,
 140                                struct dma_buf_attachment *attach)
 141 {
 142         struct drm_prime_attachment *prime_attach = attach->priv;
 143         struct drm_gem_object *obj = dma_buf->priv;
 144         struct drm_device *dev = obj->dev;
 145         struct sg_table *sgt;
 146
 147         if (dev->driver->gem_prime_unpin)
 148                 dev->driver->gem_prime_unpin(obj);
 149
 150         if (!prime_attach)
 151                 return;
 152
 153         sgt = prime_attach->sgt;
 154         if (sgt) {
 155                 if (prime_attach->dir != DMA_NONE)
 156                         dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 157                                         prime_attach->dir);
 158                 sg_free_table(sgt);
 159         }
 160
 161         kfree(sgt);
 162         kfree(prime_attach);
 163         attach->priv = NULL;
 164 }
 165
 166 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 167                                         struct dma_buf *dma_buf)
 168 {
 169         struct drm_prime_member *member, *safe;
 170
 171         list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
 172                 if (member->dma_buf == dma_buf) {
 173                         dma_buf_put(dma_buf);
 174                         list_del(&member->entry);
 175                         kfree(member);
 176                 }
 177         }
 178 }
 179
 180 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 181                                             enum dma_data_direction dir)
 182 {
 183         struct drm_prime_attachment *prime_attach = attach->priv;
 184         struct drm_gem_object *obj = attach->dmabuf->priv;
 185         struct sg_table *sgt;
 186
 187         if (WARN_ON(dir == DMA_NONE || !prime_attach))
 188                 return ERR_PTR(-EINVAL);
 189
 190         /* return the cached mapping when possible */
 191         if (prime_attach->dir == dir)
 192                 return prime_attach->sgt;
 193
 194         /*
 195          * two mappings with different directions for the same attachment are
 196          * not allowed
 197          */
 198         if (WARN_ON(prime_attach->dir != DMA_NONE))
 199                 return ERR_PTR(-EBUSY);
 200
 201         sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 202
 203         if (!IS_ERR(sgt)) {
 204                 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
 205                         sg_free_table(sgt);
 206                         kfree(sgt);
 207                         sgt = ERR_PTR(-ENOMEM);
 208                 } else {
 209                         prime_attach->sgt = sgt;
 210                         prime_attach->dir = dir;
 211                 }
 212         }
 213
 214         return sgt;
 215 }
 216
 217 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 218                                   struct sg_table *sgt,
 219                                   enum dma_data_direction dir)
 220 {
 221         /* nothing to be done here */
 222 }
 223
 224 /**
 225  * drm_gem_dmabuf_release - dma_buf release implementation for GEM
 226  * @dma_buf: buffer to be released
 227  *
 228  * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
 229  * must use this in their dma_buf ops structure as the release callback.
 230  */
 231 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 232 {
 233         struct drm_gem_object *obj = dma_buf->priv;
 234
 235         /* drop the reference on the export fd holds */
 236         drm_gem_object_unreference_unlocked(obj);
 237 }
 238 EXPORT_SYMBOL(drm_gem_dmabuf_release);
 239
 240 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 241 {
 242         struct drm_gem_object *obj = dma_buf->priv;
 243         struct drm_device *dev = obj->dev;
 244
 245         return dev->driver->gem_prime_vmap(obj);
 246 }
 247
 248 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 249 {
 250         struct drm_gem_object *obj = dma_buf->priv;
 251         struct drm_device *dev = obj->dev;
 252
 253         dev->driver->gem_prime_vunmap(obj, vaddr);
 254 }
 255
 256 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
 257                                         unsigned long page_num)
 258 {
 259         return NULL;
 260 }
 261
 262 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 263                                          unsigned long page_num, void *addr)
 264 {
 265
 266 }
 267 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 268                                  unsigned long page_num)
 269 {
 270         return NULL;
 271 }
 272
 273 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 274                                   unsigned long page_num, void *addr)
 275 {
 276
 277 }
 278
 279 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 280                                struct vm_area_struct *vma)
 281 {
 282         struct drm_gem_object *obj = dma_buf->priv;
 283         struct drm_device *dev = obj->dev;
 284
 285         if (!dev->driver->gem_prime_mmap)
 286                 return -ENOSYS;
 287
 288         return dev->driver->gem_prime_mmap(obj, vma);
 289 }
 290
 291 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 292         .attach = drm_gem_map_attach,
 293         .detach = drm_gem_map_detach,
 294         .map_dma_buf = drm_gem_map_dma_buf,
 295         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 296         .release = drm_gem_dmabuf_release,
 297         .kmap = drm_gem_dmabuf_kmap,
 298         .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
 299         .kunmap = drm_gem_dmabuf_kunmap,
 300         .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 301         .mmap = drm_gem_dmabuf_mmap,
 302         .vmap = drm_gem_dmabuf_vmap,
 303         .vunmap = drm_gem_dmabuf_vunmap,
 304 };
 305
 306 /**
 307  * DOC: PRIME Helpers
 308  *
 309  * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 310  * simpler APIs by using the helper functions @drm_gem_prime_export and
 311  * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 312  * five lower-level driver callbacks:
 313  *
 314  * Export callbacks:
 315  *
 316  *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 317  *
 318  *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 319  *
 320  *  - @gem_prime_vmap: vmap a buffer exported by your driver
 321  *
 322  *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 323  *
 324  * Import callback:
 325  *
 326  *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 327  *    driver's scatter/gather table
 328  */
 329
 330 /**
 331  * drm_gem_prime_export - helper library implementation of the export callback
 332  * @dev: drm_device to export from
 333  * @obj: GEM object to export
 334  * @flags: flags like DRM_CLOEXEC
 335  *
 336  * This is the implementation of the gem_prime_export functions for GEM drivers
 337  * using the PRIME helpers.
 338  */
 339 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 340                                      struct drm_gem_object *obj, int flags)
 341 {
 342         struct reservation_object *robj = NULL;
 343
 344         if (dev->driver->gem_prime_res_obj)
 345                 robj = dev->driver->gem_prime_res_obj(obj);
 346
 347         return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
 348                               flags, robj);
 349 }
 350 EXPORT_SYMBOL(drm_gem_prime_export);
 351
 352 static struct dma_buf *export_and_register_object(struct drm_device *dev,
 353                                                   struct drm_gem_object *obj,
 354                                                   uint32_t flags)
 355 {
 356         struct dma_buf *dmabuf;
 357
 358         /* prevent races with concurrent gem_close. */
 359         if (obj->handle_count == 0) {
 360                 dmabuf = ERR_PTR(-ENOENT);
 361                 return dmabuf;
 362         }
 363
 364         dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
 365         if (IS_ERR(dmabuf)) {
 366                 /* normally the created dma-buf takes ownership of the ref,
 367                  * but if that fails then drop the ref
 368                  */
 369                 return dmabuf;
 370         }
 371
 372         /*
 373          * Note that callers do not need to clean up the export cache
 374          * since the check for obj->handle_count guarantees that someone
 375          * will clean it up.
 376          */
 377         obj->dma_buf = dmabuf;
 378         get_dma_buf(obj->dma_buf);
 379         /* Grab a new ref since the callers is now used by the dma-buf */
 380         drm_gem_object_reference(obj);
 381
 382         return dmabuf;
 383 }
 384
 385 /**
 386  * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
 387  * @dev: dev to export the buffer from
 388  * @file_priv: drm file-private structure
 389  * @handle: buffer handle to export
 390  * @flags: flags like DRM_CLOEXEC
 391  * @prime_fd: pointer to storage for the fd id of the create dma-buf
 392  *
 393  * This is the PRIME export function which must be used mandatorily by GEM
 394  * drivers to ensure correct lifetime management of the underlying GEM object.
 395  * The actual exporting from GEM object to a dma-buf is done through the
 396  * gem_prime_export driver callback.
 397  */
 398 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 399                                struct drm_file *file_priv, uint32_t handle,
 400                                uint32_t flags,
 401                                int *prime_fd)
 402 {
 403         struct drm_gem_object *obj;
 404         int ret = 0;
 405         struct dma_buf *dmabuf;
 406
 407         mutex_lock(&file_priv->prime.lock);
 408         obj = drm_gem_object_lookup(dev, file_priv, handle);
 409         if (!obj)  {
 410                 ret = -ENOENT;
 411                 goto out_unlock;
 412         }
 413
 414         dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
 415         if (dmabuf) {
 416                 get_dma_buf(dmabuf);
 417                 goto out_have_handle;
 418         }
 419
 420         mutex_lock(&dev->object_name_lock);
 421         /* re-export the original imported object */
 422         if (obj->import_attach) {
 423                 dmabuf = obj->import_attach->dmabuf;
 424                 get_dma_buf(dmabuf);
 425                 goto out_have_obj;
 426         }
 427
 428         if (obj->dma_buf) {
 429                 get_dma_buf(obj->dma_buf);
 430                 dmabuf = obj->dma_buf;
 431                 goto out_have_obj;
 432         }
 433
 434         dmabuf = export_and_register_object(dev, obj, flags);
 435         if (IS_ERR(dmabuf)) {
 436                 /* normally the created dma-buf takes ownership of the ref,
 437                  * but if that fails then drop the ref
 438                  */
 439                 ret = PTR_ERR(dmabuf);
 440                 mutex_unlock(&dev->object_name_lock);
 441                 goto out;
 442         }
 443
 444 out_have_obj:
 445         /*
 446          * If we've exported this buffer then cheat and add it to the import list
 447          * so we get the correct handle back. We must do this under the
 448          * protection of dev->object_name_lock to ensure that a racing gem close
 449          * ioctl doesn't miss to remove this buffer handle from the cache.
 450          */
 451         ret = drm_prime_add_buf_handle(&file_priv->prime,
 452                                        dmabuf, handle);
 453         mutex_unlock(&dev->object_name_lock);
 454         if (ret)
 455                 goto fail_put_dmabuf;
 456
 457 out_have_handle:
 458         ret = dma_buf_fd(dmabuf, flags);
 459         /*
 460          * We must _not_ remove the buffer from the handle cache since the newly
 461          * created dma buf is already linked in the global obj->dma_buf pointer,
 462          * and that is invariant as long as a userspace gem handle exists.
 463          * Closing the handle will clean out the cache anyway, so we don't leak.
 464          */
 465         if (ret < 0) {
 466                 goto fail_put_dmabuf;
 467         } else {
 468                 *prime_fd = ret;
 469                 ret = 0;
 470         }
 471
 472         goto out;
 473
 474 fail_put_dmabuf:
 475         dma_buf_put(dmabuf);
 476 out:
 477         drm_gem_object_unreference_unlocked(obj);
 478 out_unlock:
 479         mutex_unlock(&file_priv->prime.lock);
 480
 481         return ret;
 482 }
 483 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 484
 485 /**
 486  * drm_gem_prime_import - helper library implementation of the import callback
 487  * @dev: drm_device to import into
 488  * @dma_buf: dma-buf object to import
 489  *
 490  * This is the implementation of the gem_prime_import functions for GEM drivers
 491  * using the PRIME helpers.
 492  */
 493 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 494                                             struct dma_buf *dma_buf)
 495 {
 496         struct dma_buf_attachment *attach;
 497         struct sg_table *sgt;
 498         struct drm_gem_object *obj;
 499         int ret;
 500
 501         if (!dev->driver->gem_prime_import_sg_table)
 502                 return ERR_PTR(-EINVAL);
 503
 504         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 505                 obj = dma_buf->priv;
 506                 if (obj->dev == dev) {
 507                         /*
 508                          * Importing dmabuf exported from out own gem increases
 509                          * refcount on gem itself instead of f_count of dmabuf.
 510                          */
 511                         drm_gem_object_reference(obj);
 512                         return obj;
 513                 }
 514         }
 515
 516         attach = dma_buf_attach(dma_buf, dev->dev);
 517         if (IS_ERR(attach))
 518                 return ERR_CAST(attach);
 519
 520         get_dma_buf(dma_buf);
 521
 522         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 523         if (IS_ERR(sgt)) {
 524                 ret = PTR_ERR(sgt);
 525                 goto fail_detach;
 526         }
 527
 528         obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
 529         if (IS_ERR(obj)) {
 530                 ret = PTR_ERR(obj);
 531                 goto fail_unmap;
 532         }
 533
 534         obj->import_attach = attach;
 535
 536         return obj;
 537
 538 fail_unmap:
 539         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 540 fail_detach:
 541         dma_buf_detach(dma_buf, attach);
 542         dma_buf_put(dma_buf);
 543
 544         return ERR_PTR(ret);
 545 }
 546 EXPORT_SYMBOL(drm_gem_prime_import);
 547
 548 /**
 549  * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
 550  * @dev: dev to export the buffer from
 551  * @file_priv: drm file-private structure
 552  * @prime_fd: fd id of the dma-buf which should be imported
 553  * @handle: pointer to storage for the handle of the imported buffer object
 554  *
 555  * This is the PRIME import function which must be used mandatorily by GEM
 556  * drivers to ensure correct lifetime management of the underlying GEM object.
 557  * The actual importing of GEM object from the dma-buf is done through the
 558  * gem_import_export driver callback.
 559  */
 560 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 561                                struct drm_file *file_priv, int prime_fd,
 562                                uint32_t *handle)
 563 {
 564         struct dma_buf *dma_buf;
 565         struct drm_gem_object *obj;
 566         int ret;
 567
 568         dma_buf = dma_buf_get(prime_fd);
 569         if (IS_ERR(dma_buf))
 570                 return PTR_ERR(dma_buf);
 571
 572         mutex_lock(&file_priv->prime.lock);
 573
 574         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 575                         dma_buf, handle);
 576         if (ret == 0)
 577                 goto out_put;
 578
 579         /* never seen this one, need to import */
 580         mutex_lock(&dev->object_name_lock);
 581         obj = dev->driver->gem_prime_import(dev, dma_buf);
 582         if (IS_ERR(obj)) {
 583                 ret = PTR_ERR(obj);
 584                 goto out_unlock;
 585         }
 586
 587         if (obj->dma_buf) {
 588                 WARN_ON(obj->dma_buf != dma_buf);
 589         } else {
 590                 obj->dma_buf = dma_buf;
 591                 get_dma_buf(dma_buf);
 592         }
 593
 594         /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
 595         ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 596         drm_gem_object_unreference_unlocked(obj);
 597         if (ret)
 598                 goto out_put;
 599
 600         ret = drm_prime_add_buf_handle(&file_priv->prime,
 601                         dma_buf, *handle);
 602         if (ret)
 603                 goto fail;
 604
 605         mutex_unlock(&file_priv->prime.lock);
 606
 607         dma_buf_put(dma_buf);
 608
 609         return 0;
 610
 611 fail:
 612         /* hmm, if driver attached, we are relying on the free-object path
 613          * to detach.. which seems ok..
 614          */
 615         drm_gem_handle_delete(file_priv, *handle);
 616 out_unlock:
 617         mutex_unlock(&dev->object_name_lock);
 618 out_put:
 619         dma_buf_put(dma_buf);
 620         mutex_unlock(&file_priv->prime.lock);
 621         return ret;
 622 }
 623 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 624
 625 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 626                                  struct drm_file *file_priv)
 627 {
 628         struct drm_prime_handle *args = data;
 629         uint32_t flags;
 630
 631         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 632                 return -EINVAL;
 633
 634         if (!dev->driver->prime_handle_to_fd)
 635                 return -ENOSYS;
 636
 637         /* check flags are valid */
 638         if (args->flags & ~DRM_CLOEXEC)
 639                 return -EINVAL;
 640
 641         /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
 642         flags = args->flags & DRM_CLOEXEC;
 643
 644         return dev->driver->prime_handle_to_fd(dev, file_priv,
 645                         args->handle, flags, &args->fd);
 646 }
 647
 648 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 649                                  struct drm_file *file_priv)
 650 {
 651         struct drm_prime_handle *args = data;
 652
 653         if (!drm_core_check_feature(dev, DRIVER_PRIME))
 654                 return -EINVAL;
 655
 656         if (!dev->driver->prime_fd_to_handle)
 657                 return -ENOSYS;
 658
 659         return dev->driver->prime_fd_to_handle(dev, file_priv,
 660                         args->fd, &args->handle);
 661 }
 662
 663 /**
 664  * drm_prime_pages_to_sg - converts a page array into an sg list
 665  * @pages: pointer to the array of page pointers to convert
 666  * @nr_pages: length of the page vector
 667  *
 668  * This helper creates an sg table object from a set of pages
 669  * the driver is responsible for mapping the pages into the
 670  * importers address space for use with dma_buf itself.
 671  */
 672 struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
 673 {
 674         struct sg_table *sg = NULL;
 675         int ret;
 676
 677         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 678         if (!sg) {
 679                 ret = -ENOMEM;
 680                 goto out;
 681         }
 682
 683         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 684                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 685         if (ret)
 686                 goto out;
 687
 688         return sg;
 689 out:
 690         kfree(sg);
 691         return ERR_PTR(ret);
 692 }
 693 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 694
 695 /**
 696  * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
 697  * @sgt: scatter-gather table to convert
 698  * @pages: array of page pointers to store the page array in
 699  * @addrs: optional array to store the dma bus address of each page
 700  * @max_pages: size of both the passed-in arrays
 701  *
 702  * Exports an sg table into an array of pages and addresses. This is currently
 703  * required by the TTM driver in order to do correct fault handling.
 704  */
 705 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 706                                      dma_addr_t *addrs, int max_pages)
 707 {
 708         unsigned count;
 709         struct scatterlist *sg;
 710         struct page *page;
 711         u32 len;
 712         int pg_index;
 713         dma_addr_t addr;
 714
 715         pg_index = 0;
 716         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 717                 len = sg->length;
 718                 page = sg_page(sg);
 719                 addr = sg_dma_address(sg);
 720
 721                 while (len > 0) {
 722                         if (WARN_ON(pg_index >= max_pages))
 723                                 return -1;
 724                         pages[pg_index] = page;
 725                         if (addrs)
 726                                 addrs[pg_index] = addr;
 727
 728                         page++;
 729                         addr += PAGE_SIZE;
 730                         len -= PAGE_SIZE;
 731                         pg_index++;
 732                 }
 733         }
 734         return 0;
 735 }
 736 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 737
 738 /**
 739  * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
 740  * @obj: GEM object which was created from a dma-buf
 741  * @sg: the sg-table which was pinned at import time
 742  *
 743  * This is the cleanup functions which GEM drivers need to call when they use
 744  * @drm_gem_prime_import to import dma-bufs.
 745  */
 746 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 747 {
 748         struct dma_buf_attachment *attach;
 749         struct dma_buf *dma_buf;
 750         attach = obj->import_attach;
 751         if (sg)
 752                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 753         dma_buf = attach->dmabuf;
 754         dma_buf_detach(attach->dmabuf, attach);
 755         /* remove the reference */
 756         dma_buf_put(dma_buf);
 757 }
 758 EXPORT_SYMBOL(drm_prime_gem_destroy);
 759
 760 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 761 {
 762         INIT_LIST_HEAD(&prime_fpriv->head);
 763         mutex_init(&prime_fpriv->lock);
 764 }
 765
 766 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 767 {
 768         /* by now drm_gem_release should've made sure the list is empty */
 769         WARN_ON(!list_empty(&prime_fpriv->head));
 770 }