drivers/gpu/drm/drm_gem.c

   1 /*
   2  * Copyright © 2008 Intel Corporation
   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  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 #include <linux/types.h>
  29 #include <linux/slab.h>
  30 #include <linux/mm.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/fs.h>
  33 #include <linux/file.h>
  34 #include <linux/module.h>
  35 #include <linux/mman.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/shmem_fs.h>
  38 #include <linux/dma-buf.h>
  39 #include <drm/drmP.h>
  40
  41 /** @file drm_gem.c
  42  *
  43  * This file provides some of the base ioctls and library routines for
  44  * the graphics memory manager implemented by each device driver.
  45  *
  46  * Because various devices have different requirements in terms of
  47  * synchronization and migration strategies, implementing that is left up to
  48  * the driver, and all that the general API provides should be generic --
  49  * allocating objects, reading/writing data with the cpu, freeing objects.
  50  * Even there, platform-dependent optimizations for reading/writing data with
  51  * the CPU mean we'll likely hook those out to driver-specific calls.  However,
  52  * the DRI2 implementation wants to have at least allocate/mmap be generic.
  53  *
  54  * The goal was to have swap-backed object allocation managed through
  55  * struct file.  However, file descriptors as handles to a struct file have
  56  * two major failings:
  57  * - Process limits prevent more than 1024 or so being used at a time by
  58  *   default.
  59  * - Inability to allocate high fds will aggravate the X Server's select()
  60  *   handling, and likely that of many GL client applications as well.
  61  *
  62  * This led to a plan of using our own integer IDs (called handles, following
  63  * DRM terminology) to mimic fds, and implement the fd syscalls we need as
  64  * ioctls.  The objects themselves will still include the struct file so
  65  * that we can transition to fds if the required kernel infrastructure shows
  66  * up at a later date, and as our interface with shmfs for memory allocation.
  67  */
  68
  69 /*
  70  * We make up offsets for buffer objects so we can recognize them at
  71  * mmap time.
  72  */
  73
  74 /* pgoff in mmap is an unsigned long, so we need to make sure that
  75  * the faked up offset will fit
  76  */
  77
  78 #if BITS_PER_LONG == 64
  79 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
  80 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
  81 #else
  82 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
  83 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
  84 #endif
  85
  86 /**
  87  * Initialize the GEM device fields
  88  */
  89
  90 int
  91 drm_gem_init(struct drm_device *dev)
  92 {
  93         struct drm_gem_mm *mm;
  94
  95         spin_lock_init(&dev->object_name_lock);
  96         idr_init(&dev->object_name_idr);
  97
  98         mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
  99         if (!mm) {
 100                 DRM_ERROR("out of memory\n");
 101                 return -ENOMEM;
 102         }
 103
 104         dev->mm_private = mm;
 105
 106         if (drm_ht_create(&mm->offset_hash, 12)) {
 107                 kfree(mm);
 108                 return -ENOMEM;
 109         }
 110
 111         if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
 112                         DRM_FILE_PAGE_OFFSET_SIZE)) {
 113                 drm_ht_remove(&mm->offset_hash);
 114                 kfree(mm);
 115                 return -ENOMEM;
 116         }
 117
 118         return 0;
 119 }
 120
 121 void
 122 drm_gem_destroy(struct drm_device *dev)
 123 {
 124         struct drm_gem_mm *mm = dev->mm_private;
 125
 126         drm_mm_takedown(&mm->offset_manager);
 127         drm_ht_remove(&mm->offset_hash);
 128         kfree(mm);
 129         dev->mm_private = NULL;
 130 }
 131
 132 /**
 133  * Initialize an already allocated GEM object of the specified size with
 134  * shmfs backing store.
 135  */
 136 int drm_gem_object_init(struct drm_device *dev,
 137                         struct drm_gem_object *obj, size_t size)
 138 {
 139         BUG_ON((size & (PAGE_SIZE - 1)) != 0);
 140
 141         obj->dev = dev;
 142         obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
 143         if (IS_ERR(obj->filp))
 144                 return PTR_ERR(obj->filp);
 145
 146         kref_init(&obj->refcount);
 147         atomic_set(&obj->handle_count, 0);
 148         obj->size = size;
 149
 150         return 0;
 151 }
 152 EXPORT_SYMBOL(drm_gem_object_init);
 153
 154 /**
 155  * Initialize an already allocated GEM object of the specified size with
 156  * no GEM provided backing store. Instead the caller is responsible for
 157  * backing the object and handling it.
 158  */
 159 int drm_gem_private_object_init(struct drm_device *dev,
 160                         struct drm_gem_object *obj, size_t size)
 161 {
 162         BUG_ON((size & (PAGE_SIZE - 1)) != 0);
 163
 164         obj->dev = dev;
 165         obj->filp = NULL;
 166
 167         kref_init(&obj->refcount);
 168         atomic_set(&obj->handle_count, 0);
 169         obj->size = size;
 170
 171         return 0;
 172 }
 173 EXPORT_SYMBOL(drm_gem_private_object_init);
 174
 175 /**
 176  * Allocate a GEM object of the specified size with shmfs backing store
 177  */
 178 struct drm_gem_object *
 179 drm_gem_object_alloc(struct drm_device *dev, size_t size)
 180 {
 181         struct drm_gem_object *obj;
 182
 183         obj = kzalloc(sizeof(*obj), GFP_KERNEL);
 184         if (!obj)
 185                 goto free;
 186
 187         if (drm_gem_object_init(dev, obj, size) != 0)
 188                 goto free;
 189
 190         if (dev->driver->gem_init_object != NULL &&
 191             dev->driver->gem_init_object(obj) != 0) {
 192                 goto fput;
 193         }
 194         return obj;
 195 fput:
 196         /* Object_init mangles the global counters - readjust them. */
 197         fput(obj->filp);
 198 free:
 199         kfree(obj);
 200         return NULL;
 201 }
 202 EXPORT_SYMBOL(drm_gem_object_alloc);
 203
 204 static void
 205 drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
 206 {
 207         if (obj->import_attach) {
 208                 drm_prime_remove_buf_handle(&filp->prime,
 209                                 obj->import_attach->dmabuf);
 210         }
 211         if (obj->export_dma_buf) {
 212                 drm_prime_remove_buf_handle(&filp->prime,
 213                                 obj->export_dma_buf);
 214         }
 215 }
 216
 217 /**
 218  * Removes the mapping from handle to filp for this object.
 219  */
 220 int
 221 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
 222 {
 223         struct drm_device *dev;
 224         struct drm_gem_object *obj;
 225
 226         /* This is gross. The idr system doesn't let us try a delete and
 227          * return an error code.  It just spews if you fail at deleting.
 228          * So, we have to grab a lock around finding the object and then
 229          * doing the delete on it and dropping the refcount, or the user
 230          * could race us to double-decrement the refcount and cause a
 231          * use-after-free later.  Given the frequency of our handle lookups,
 232          * we may want to use ida for number allocation and a hash table
 233          * for the pointers, anyway.
 234          */
 235         spin_lock(&filp->table_lock);
 236
 237         /* Check if we currently have a reference on the object */
 238         obj = idr_find(&filp->object_idr, handle);
 239         if (obj == NULL) {
 240                 spin_unlock(&filp->table_lock);
 241                 return -EINVAL;
 242         }
 243         dev = obj->dev;
 244
 245         /* Release reference and decrement refcount. */
 246         idr_remove(&filp->object_idr, handle);
 247         spin_unlock(&filp->table_lock);
 248
 249         drm_gem_remove_prime_handles(obj, filp);
 250
 251         if (dev->driver->gem_close_object)
 252                 dev->driver->gem_close_object(obj, filp);
 253         drm_gem_object_handle_unreference_unlocked(obj);
 254
 255         return 0;
 256 }
 257 EXPORT_SYMBOL(drm_gem_handle_delete);
 258
 259 /**
 260  * Create a handle for this object. This adds a handle reference
 261  * to the object, which includes a regular reference count. Callers
 262  * will likely want to dereference the object afterwards.
 263  */
 264 int
 265 drm_gem_handle_create(struct drm_file *file_priv,
 266                        struct drm_gem_object *obj,
 267                        u32 *handlep)
 268 {
 269         struct drm_device *dev = obj->dev;
 270         int ret;
 271
 272         /*
 273          * Get the user-visible handle using idr.  Preload and perform
 274          * allocation under our spinlock.
 275          */
 276         idr_preload(GFP_KERNEL);
 277         spin_lock(&file_priv->table_lock);
 278
 279         ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
 280
 281         spin_unlock(&file_priv->table_lock);
 282         idr_preload_end();
 283         if (ret < 0)
 284                 return ret;
 285         *handlep = ret;
 286
 287         drm_gem_object_handle_reference(obj);
 288
 289         if (dev->driver->gem_open_object) {
 290                 ret = dev->driver->gem_open_object(obj, file_priv);
 291                 if (ret) {
 292                         drm_gem_handle_delete(file_priv, *handlep);
 293                         return ret;
 294                 }
 295         }
 296
 297         return 0;
 298 }
 299 EXPORT_SYMBOL(drm_gem_handle_create);
 300
 301
 302 /**
 303  * drm_gem_free_mmap_offset - release a fake mmap offset for an object
 304  * @obj: obj in question
 305  *
 306  * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
 307  */
 308 void
 309 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
 310 {
 311         struct drm_device *dev = obj->dev;
 312         struct drm_gem_mm *mm = dev->mm_private;
 313         struct drm_map_list *list = &obj->map_list;
 314
 315         drm_ht_remove_item(&mm->offset_hash, &list->hash);
 316         drm_mm_put_block(list->file_offset_node);
 317         kfree(list->map);
 318         list->map = NULL;
 319 }
 320 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
 321
 322 /**
 323  * drm_gem_create_mmap_offset - create a fake mmap offset for an object
 324  * @obj: obj in question
 325  *
 326  * GEM memory mapping works by handing back to userspace a fake mmap offset
 327  * it can use in a subsequent mmap(2) call.  The DRM core code then looks
 328  * up the object based on the offset and sets up the various memory mapping
 329  * structures.
 330  *
 331  * This routine allocates and attaches a fake offset for @obj.
 332  */
 333 int
 334 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
 335 {
 336         struct drm_device *dev = obj->dev;
 337         struct drm_gem_mm *mm = dev->mm_private;
 338         struct drm_map_list *list;
 339         struct drm_local_map *map;
 340         int ret;
 341
 342         /* Set the object up for mmap'ing */
 343         list = &obj->map_list;
 344         list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL);
 345         if (!list->map)
 346                 return -ENOMEM;
 347
 348         map = list->map;
 349         map->type = _DRM_GEM;
 350         map->size = obj->size;
 351         map->handle = obj;
 352
 353         /* Get a DRM GEM mmap offset allocated... */
 354         list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
 355                         obj->size / PAGE_SIZE, 0, false);
 356
 357         if (!list->file_offset_node) {
 358                 DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
 359                 ret = -ENOSPC;
 360                 goto out_free_list;
 361         }
 362
 363         list->file_offset_node = drm_mm_get_block(list->file_offset_node,
 364                         obj->size / PAGE_SIZE, 0);
 365         if (!list->file_offset_node) {
 366                 ret = -ENOMEM;
 367                 goto out_free_list;
 368         }
 369
 370         list->hash.key = list->file_offset_node->start;
 371         ret = drm_ht_insert_item(&mm->offset_hash, &list->hash);
 372         if (ret) {
 373                 DRM_ERROR("failed to add to map hash\n");
 374                 goto out_free_mm;
 375         }
 376
 377         return 0;
 378
 379 out_free_mm:
 380         drm_mm_put_block(list->file_offset_node);
 381 out_free_list:
 382         kfree(list->map);
 383         list->map = NULL;
 384
 385         return ret;
 386 }
 387 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
 388
 389 /** Returns a reference to the object named by the handle. */
 390 struct drm_gem_object *
 391 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
 392                       u32 handle)
 393 {
 394         struct drm_gem_object *obj;
 395
 396         spin_lock(&filp->table_lock);
 397
 398         /* Check if we currently have a reference on the object */
 399         obj = idr_find(&filp->object_idr, handle);
 400         if (obj == NULL) {
 401                 spin_unlock(&filp->table_lock);
 402                 return NULL;
 403         }
 404
 405         drm_gem_object_reference(obj);
 406
 407         spin_unlock(&filp->table_lock);
 408
 409         return obj;
 410 }
 411 EXPORT_SYMBOL(drm_gem_object_lookup);
 412
 413 /**
 414  * Releases the handle to an mm object.
 415  */
 416 int
 417 drm_gem_close_ioctl(struct drm_device *dev, void *data,
 418                     struct drm_file *file_priv)
 419 {
 420         struct drm_gem_close *args = data;
 421         int ret;
 422
 423         if (!(dev->driver->driver_features & DRIVER_GEM))
 424                 return -ENODEV;
 425
 426         ret = drm_gem_handle_delete(file_priv, args->handle);
 427
 428         return ret;
 429 }
 430
 431 /**
 432  * Create a global name for an object, returning the name.
 433  *
 434  * Note that the name does not hold a reference; when the object
 435  * is freed, the name goes away.
 436  */
 437 int
 438 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
 439                     struct drm_file *file_priv)
 440 {
 441         struct drm_gem_flink *args = data;
 442         struct drm_gem_object *obj;
 443         int ret;
 444
 445         if (!(dev->driver->driver_features & DRIVER_GEM))
 446                 return -ENODEV;
 447
 448         obj = drm_gem_object_lookup(dev, file_priv, args->handle);
 449         if (obj == NULL)
 450                 return -ENOENT;
 451
 452         idr_preload(GFP_KERNEL);
 453         spin_lock(&dev->object_name_lock);
 454         if (!obj->name) {
 455                 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
 456                 obj->name = ret;
 457                 args->name = (uint64_t) obj->name;
 458                 spin_unlock(&dev->object_name_lock);
 459                 idr_preload_end();
 460
 461                 if (ret < 0)
 462                         goto err;
 463                 ret = 0;
 464
 465                 /* Allocate a reference for the name table.  */
 466                 drm_gem_object_reference(obj);
 467         } else {
 468                 args->name = (uint64_t) obj->name;
 469                 spin_unlock(&dev->object_name_lock);
 470                 idr_preload_end();
 471                 ret = 0;
 472         }
 473
 474 err:
 475         drm_gem_object_unreference_unlocked(obj);
 476         return ret;
 477 }
 478
 479 /**
 480  * Open an object using the global name, returning a handle and the size.
 481  *
 482  * This handle (of course) holds a reference to the object, so the object
 483  * will not go away until the handle is deleted.
 484  */
 485 int
 486 drm_gem_open_ioctl(struct drm_device *dev, void *data,
 487                    struct drm_file *file_priv)
 488 {
 489         struct drm_gem_open *args = data;
 490         struct drm_gem_object *obj;
 491         int ret;
 492         u32 handle;
 493
 494         if (!(dev->driver->driver_features & DRIVER_GEM))
 495                 return -ENODEV;
 496
 497         spin_lock(&dev->object_name_lock);
 498         obj = idr_find(&dev->object_name_idr, (int) args->name);
 499         if (obj)
 500                 drm_gem_object_reference(obj);
 501         spin_unlock(&dev->object_name_lock);
 502         if (!obj)
 503                 return -ENOENT;
 504
 505         ret = drm_gem_handle_create(file_priv, obj, &handle);
 506         drm_gem_object_unreference_unlocked(obj);
 507         if (ret)
 508                 return ret;
 509
 510         args->handle = handle;
 511         args->size = obj->size;
 512
 513         return 0;
 514 }
 515
 516 /**
 517  * Called at device open time, sets up the structure for handling refcounting
 518  * of mm objects.
 519  */
 520 void
 521 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
 522 {
 523         idr_init(&file_private->object_idr);
 524         spin_lock_init(&file_private->table_lock);
 525 }
 526
 527 /**
 528  * Called at device close to release the file's
 529  * handle references on objects.
 530  */
 531 static int
 532 drm_gem_object_release_handle(int id, void *ptr, void *data)
 533 {
 534         struct drm_file *file_priv = data;
 535         struct drm_gem_object *obj = ptr;
 536         struct drm_device *dev = obj->dev;
 537
 538         drm_gem_remove_prime_handles(obj, file_priv);
 539
 540         if (dev->driver->gem_close_object)
 541                 dev->driver->gem_close_object(obj, file_priv);
 542
 543         drm_gem_object_handle_unreference_unlocked(obj);
 544
 545         return 0;
 546 }
 547
 548 /**
 549  * Called at close time when the filp is going away.
 550  *
 551  * Releases any remaining references on objects by this filp.
 552  */
 553 void
 554 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
 555 {
 556         idr_for_each(&file_private->object_idr,
 557                      &drm_gem_object_release_handle, file_private);
 558         idr_destroy(&file_private->object_idr);
 559 }
 560
 561 void
 562 drm_gem_object_release(struct drm_gem_object *obj)
 563 {
 564         if (obj->filp)
 565             fput(obj->filp);
 566 }
 567 EXPORT_SYMBOL(drm_gem_object_release);
 568
 569 /**
 570  * Called after the last reference to the object has been lost.
 571  * Must be called holding struct_ mutex
 572  *
 573  * Frees the object
 574  */
 575 void
 576 drm_gem_object_free(struct kref *kref)
 577 {
 578         struct drm_gem_object *obj = (struct drm_gem_object *) kref;
 579         struct drm_device *dev = obj->dev;
 580
 581         BUG_ON(!mutex_is_locked(&dev->struct_mutex));
 582
 583         if (dev->driver->gem_free_object != NULL)
 584                 dev->driver->gem_free_object(obj);
 585 }
 586 EXPORT_SYMBOL(drm_gem_object_free);
 587
 588 static void drm_gem_object_ref_bug(struct kref *list_kref)
 589 {
 590         BUG();
 591 }
 592
 593 /**
 594  * Called after the last handle to the object has been closed
 595  *
 596  * Removes any name for the object. Note that this must be
 597  * called before drm_gem_object_free or we'll be touching
 598  * freed memory
 599  */
 600 void drm_gem_object_handle_free(struct drm_gem_object *obj)
 601 {
 602         struct drm_device *dev = obj->dev;
 603
 604         /* Remove any name for this object */
 605         spin_lock(&dev->object_name_lock);
 606         if (obj->name) {
 607                 idr_remove(&dev->object_name_idr, obj->name);
 608                 obj->name = 0;
 609                 spin_unlock(&dev->object_name_lock);
 610                 /*
 611                  * The object name held a reference to this object, drop
 612                  * that now.
 613                 *
 614                 * This cannot be the last reference, since the handle holds one too.
 615                  */
 616                 kref_put(&obj->refcount, drm_gem_object_ref_bug);
 617         } else
 618                 spin_unlock(&dev->object_name_lock);
 619
 620 }
 621 EXPORT_SYMBOL(drm_gem_object_handle_free);
 622
 623 void drm_gem_vm_open(struct vm_area_struct *vma)
 624 {
 625         struct drm_gem_object *obj = vma->vm_private_data;
 626
 627         drm_gem_object_reference(obj);
 628
 629         mutex_lock(&obj->dev->struct_mutex);
 630         drm_vm_open_locked(obj->dev, vma);
 631         mutex_unlock(&obj->dev->struct_mutex);
 632 }
 633 EXPORT_SYMBOL(drm_gem_vm_open);
 634
 635 void drm_gem_vm_close(struct vm_area_struct *vma)
 636 {
 637         struct drm_gem_object *obj = vma->vm_private_data;
 638         struct drm_device *dev = obj->dev;
 639
 640         mutex_lock(&dev->struct_mutex);
 641         drm_vm_close_locked(obj->dev, vma);
 642         drm_gem_object_unreference(obj);
 643         mutex_unlock(&dev->struct_mutex);
 644 }
 645 EXPORT_SYMBOL(drm_gem_vm_close);
 646
 647
 648 /**
 649  * drm_gem_mmap - memory map routine for GEM objects
 650  * @filp: DRM file pointer
 651  * @vma: VMA for the area to be mapped
 652  *
 653  * If a driver supports GEM object mapping, mmap calls on the DRM file
 654  * descriptor will end up here.
 655  *
 656  * If we find the object based on the offset passed in (vma->vm_pgoff will
 657  * contain the fake offset we created when the GTT map ioctl was called on
 658  * the object), we set up the driver fault handler so that any accesses
 659  * to the object can be trapped, to perform migration, GTT binding, surface
 660  * register allocation, or performance monitoring.
 661  */
 662 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 663 {
 664         struct drm_file *priv = filp->private_data;
 665         struct drm_device *dev = priv->minor->dev;
 666         struct drm_gem_mm *mm = dev->mm_private;
 667         struct drm_local_map *map = NULL;
 668         struct drm_gem_object *obj;
 669         struct drm_hash_item *hash;
 670         int ret = 0;
 671
 672         if (drm_device_is_unplugged(dev))
 673                 return -ENODEV;
 674
 675         mutex_lock(&dev->struct_mutex);
 676
 677         if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
 678                 mutex_unlock(&dev->struct_mutex);
 679                 return drm_mmap(filp, vma);
 680         }
 681
 682         map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
 683         if (!map ||
 684             ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
 685                 ret =  -EPERM;
 686                 goto out_unlock;
 687         }
 688
 689         /* Check for valid size. */
 690         if (map->size < vma->vm_end - vma->vm_start) {
 691                 ret = -EINVAL;
 692                 goto out_unlock;
 693         }
 694
 695         obj = map->handle;
 696         if (!obj->dev->driver->gem_vm_ops) {
 697                 ret = -EINVAL;
 698                 goto out_unlock;
 699         }
 700
 701         vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
 702         vma->vm_ops = obj->dev->driver->gem_vm_ops;
 703         vma->vm_private_data = map->handle;
 704         vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 705
 706         /* Take a ref for this mapping of the object, so that the fault
 707          * handler can dereference the mmap offset's pointer to the object.
 708          * This reference is cleaned up by the corresponding vm_close
 709          * (which should happen whether the vma was created by this call, or
 710          * by a vm_open due to mremap or partial unmap or whatever).
 711          */
 712         drm_gem_object_reference(obj);
 713
 714         drm_vm_open_locked(dev, vma);
 715
 716 out_unlock:
 717         mutex_unlock(&dev->struct_mutex);
 718
 719         return ret;
 720 }
 721 EXPORT_SYMBOL(drm_gem_mmap);