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 "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 /**
 205  * Removes the mapping from handle to filp for this object.
 206  */
 207 int
 208 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
 209 {
 210         struct drm_device *dev;
 211         struct drm_gem_object *obj;
 212
 213         /* This is gross. The idr system doesn't let us try a delete and
 214          * return an error code.  It just spews if you fail at deleting.
 215          * So, we have to grab a lock around finding the object and then
 216          * doing the delete on it and dropping the refcount, or the user
 217          * could race us to double-decrement the refcount and cause a
 218          * use-after-free later.  Given the frequency of our handle lookups,
 219          * we may want to use ida for number allocation and a hash table
 220          * for the pointers, anyway.
 221          */
 222         spin_lock(&filp->table_lock);
 223
 224         /* Check if we currently have a reference on the object */
 225         obj = idr_find(&filp->object_idr, handle);
 226         if (obj == NULL) {
 227                 spin_unlock(&filp->table_lock);
 228                 return -EINVAL;
 229         }
 230         dev = obj->dev;
 231
 232         /* Release reference and decrement refcount. */
 233         idr_remove(&filp->object_idr, handle);
 234         spin_unlock(&filp->table_lock);
 235
 236         if (obj->import_attach)
 237                 drm_prime_remove_imported_buf_handle(&filp->prime,
 238                                 obj->import_attach->dmabuf);
 239
 240         if (dev->driver->gem_close_object)
 241                 dev->driver->gem_close_object(obj, filp);
 242         drm_gem_object_handle_unreference_unlocked(obj);
 243
 244         return 0;
 245 }
 246 EXPORT_SYMBOL(drm_gem_handle_delete);
 247
 248 /**
 249  * Create a handle for this object. This adds a handle reference
 250  * to the object, which includes a regular reference count. Callers
 251  * will likely want to dereference the object afterwards.
 252  */
 253 int
 254 drm_gem_handle_create(struct drm_file *file_priv,
 255                        struct drm_gem_object *obj,
 256                        u32 *handlep)
 257 {
 258         struct drm_device *dev = obj->dev;
 259         int ret;
 260
 261         /*
 262          * Get the user-visible handle using idr.
 263          */
 264 again:
 265         /* ensure there is space available to allocate a handle */
 266         if (idr_pre_get(&file_priv->object_idr, GFP_KERNEL) == 0)
 267                 return -ENOMEM;
 268
 269         /* do the allocation under our spinlock */
 270         spin_lock(&file_priv->table_lock);
 271         ret = idr_get_new_above(&file_priv->object_idr, obj, 1, (int *)handlep);
 272         spin_unlock(&file_priv->table_lock);
 273         if (ret == -EAGAIN)
 274                 goto again;
 275         else if (ret)
 276                 return ret;
 277
 278         drm_gem_object_handle_reference(obj);
 279
 280         if (dev->driver->gem_open_object) {
 281                 ret = dev->driver->gem_open_object(obj, file_priv);
 282                 if (ret) {
 283                         drm_gem_handle_delete(file_priv, *handlep);
 284                         return ret;
 285                 }
 286         }
 287
 288         return 0;
 289 }
 290 EXPORT_SYMBOL(drm_gem_handle_create);
 291
 292
 293 /**
 294  * drm_gem_free_mmap_offset - release a fake mmap offset for an object
 295  * @obj: obj in question
 296  *
 297  * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
 298  */
 299 void
 300 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
 301 {
 302         struct drm_device *dev = obj->dev;
 303         struct drm_gem_mm *mm = dev->mm_private;
 304         struct drm_map_list *list = &obj->map_list;
 305
 306         drm_ht_remove_item(&mm->offset_hash, &list->hash);
 307         drm_mm_put_block(list->file_offset_node);
 308         kfree(list->map);
 309         list->map = NULL;
 310 }
 311 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
 312
 313 /**
 314  * drm_gem_create_mmap_offset - create a fake mmap offset for an object
 315  * @obj: obj in question
 316  *
 317  * GEM memory mapping works by handing back to userspace a fake mmap offset
 318  * it can use in a subsequent mmap(2) call.  The DRM core code then looks
 319  * up the object based on the offset and sets up the various memory mapping
 320  * structures.
 321  *
 322  * This routine allocates and attaches a fake offset for @obj.
 323  */
 324 int
 325 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
 326 {
 327         struct drm_device *dev = obj->dev;
 328         struct drm_gem_mm *mm = dev->mm_private;
 329         struct drm_map_list *list;
 330         struct drm_local_map *map;
 331         int ret;
 332
 333         /* Set the object up for mmap'ing */
 334         list = &obj->map_list;
 335         list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL);
 336         if (!list->map)
 337                 return -ENOMEM;
 338
 339         map = list->map;
 340         map->type = _DRM_GEM;
 341         map->size = obj->size;
 342         map->handle = obj;
 343
 344         /* Get a DRM GEM mmap offset allocated... */
 345         list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
 346                         obj->size / PAGE_SIZE, 0, 0);
 347
 348         if (!list->file_offset_node) {
 349                 DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
 350                 ret = -ENOSPC;
 351                 goto out_free_list;
 352         }
 353
 354         list->file_offset_node = drm_mm_get_block(list->file_offset_node,
 355                         obj->size / PAGE_SIZE, 0);
 356         if (!list->file_offset_node) {
 357                 ret = -ENOMEM;
 358                 goto out_free_list;
 359         }
 360
 361         list->hash.key = list->file_offset_node->start;
 362         ret = drm_ht_insert_item(&mm->offset_hash, &list->hash);
 363         if (ret) {
 364                 DRM_ERROR("failed to add to map hash\n");
 365                 goto out_free_mm;
 366         }
 367
 368         return 0;
 369
 370 out_free_mm:
 371         drm_mm_put_block(list->file_offset_node);
 372 out_free_list:
 373         kfree(list->map);
 374         list->map = NULL;
 375
 376         return ret;
 377 }
 378 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
 379
 380 /** Returns a reference to the object named by the handle. */
 381 struct drm_gem_object *
 382 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
 383                       u32 handle)
 384 {
 385         struct drm_gem_object *obj;
 386
 387         spin_lock(&filp->table_lock);
 388
 389         /* Check if we currently have a reference on the object */
 390         obj = idr_find(&filp->object_idr, handle);
 391         if (obj == NULL) {
 392                 spin_unlock(&filp->table_lock);
 393                 return NULL;
 394         }
 395
 396         drm_gem_object_reference(obj);
 397
 398         spin_unlock(&filp->table_lock);
 399
 400         return obj;
 401 }
 402 EXPORT_SYMBOL(drm_gem_object_lookup);
 403
 404 /**
 405  * Releases the handle to an mm object.
 406  */
 407 int
 408 drm_gem_close_ioctl(struct drm_device *dev, void *data,
 409                     struct drm_file *file_priv)
 410 {
 411         struct drm_gem_close *args = data;
 412         int ret;
 413
 414         if (!(dev->driver->driver_features & DRIVER_GEM))
 415                 return -ENODEV;
 416
 417         ret = drm_gem_handle_delete(file_priv, args->handle);
 418
 419         return ret;
 420 }
 421
 422 /**
 423  * Create a global name for an object, returning the name.
 424  *
 425  * Note that the name does not hold a reference; when the object
 426  * is freed, the name goes away.
 427  */
 428 int
 429 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
 430                     struct drm_file *file_priv)
 431 {
 432         struct drm_gem_flink *args = data;
 433         struct drm_gem_object *obj;
 434         int ret;
 435
 436         if (!(dev->driver->driver_features & DRIVER_GEM))
 437                 return -ENODEV;
 438
 439         obj = drm_gem_object_lookup(dev, file_priv, args->handle);
 440         if (obj == NULL)
 441                 return -ENOENT;
 442
 443 again:
 444         if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0) {
 445                 ret = -ENOMEM;
 446                 goto err;
 447         }
 448
 449         spin_lock(&dev->object_name_lock);
 450         if (!obj->name) {
 451                 ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
 452                                         &obj->name);
 453                 args->name = (uint64_t) obj->name;
 454                 spin_unlock(&dev->object_name_lock);
 455
 456                 if (ret == -EAGAIN)
 457                         goto again;
 458                 else if (ret)
 459                         goto err;
 460
 461                 /* Allocate a reference for the name table.  */
 462                 drm_gem_object_reference(obj);
 463         } else {
 464                 args->name = (uint64_t) obj->name;
 465                 spin_unlock(&dev->object_name_lock);
 466                 ret = 0;
 467         }
 468
 469 err:
 470         drm_gem_object_unreference_unlocked(obj);
 471         return ret;
 472 }
 473
 474 /**
 475  * Open an object using the global name, returning a handle and the size.
 476  *
 477  * This handle (of course) holds a reference to the object, so the object
 478  * will not go away until the handle is deleted.
 479  */
 480 int
 481 drm_gem_open_ioctl(struct drm_device *dev, void *data,
 482                    struct drm_file *file_priv)
 483 {
 484         struct drm_gem_open *args = data;
 485         struct drm_gem_object *obj;
 486         int ret;
 487         u32 handle;
 488
 489         if (!(dev->driver->driver_features & DRIVER_GEM))
 490                 return -ENODEV;
 491
 492         spin_lock(&dev->object_name_lock);
 493         obj = idr_find(&dev->object_name_idr, (int) args->name);
 494         if (obj)
 495                 drm_gem_object_reference(obj);
 496         spin_unlock(&dev->object_name_lock);
 497         if (!obj)
 498                 return -ENOENT;
 499
 500         ret = drm_gem_handle_create(file_priv, obj, &handle);
 501         drm_gem_object_unreference_unlocked(obj);
 502         if (ret)
 503                 return ret;
 504
 505         args->handle = handle;
 506         args->size = obj->size;
 507
 508         return 0;
 509 }
 510
 511 /**
 512  * Called at device open time, sets up the structure for handling refcounting
 513  * of mm objects.
 514  */
 515 void
 516 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
 517 {
 518         idr_init(&file_private->object_idr);
 519         spin_lock_init(&file_private->table_lock);
 520 }
 521
 522 /**
 523  * Called at device close to release the file's
 524  * handle references on objects.
 525  */
 526 static int
 527 drm_gem_object_release_handle(int id, void *ptr, void *data)
 528 {
 529         struct drm_file *file_priv = data;
 530         struct drm_gem_object *obj = ptr;
 531         struct drm_device *dev = obj->dev;
 532
 533         if (obj->import_attach)
 534                 drm_prime_remove_imported_buf_handle(&file_priv->prime,
 535                                 obj->import_attach->dmabuf);
 536
 537         if (dev->driver->gem_close_object)
 538                 dev->driver->gem_close_object(obj, file_priv);
 539
 540         drm_gem_object_handle_unreference_unlocked(obj);
 541
 542         return 0;
 543 }
 544
 545 /**
 546  * Called at close time when the filp is going away.
 547  *
 548  * Releases any remaining references on objects by this filp.
 549  */
 550 void
 551 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
 552 {
 553         idr_for_each(&file_private->object_idr,
 554                      &drm_gem_object_release_handle, file_private);
 555
 556         idr_remove_all(&file_private->object_idr);
 557         idr_destroy(&file_private->object_idr);
 558 }
 559
 560 void
 561 drm_gem_object_release(struct drm_gem_object *obj)
 562 {
 563         if (obj->filp)
 564             fput(obj->filp);
 565 }
 566 EXPORT_SYMBOL(drm_gem_object_release);
 567
 568 /**
 569  * Called after the last reference to the object has been lost.
 570  * Must be called holding struct_ mutex
 571  *
 572  * Frees the object
 573  */
 574 void
 575 drm_gem_object_free(struct kref *kref)
 576 {
 577         struct drm_gem_object *obj = (struct drm_gem_object *) kref;
 578         struct drm_device *dev = obj->dev;
 579
 580         BUG_ON(!mutex_is_locked(&dev->struct_mutex));
 581
 582         if (dev->driver->gem_free_object != NULL)
 583                 dev->driver->gem_free_object(obj);
 584 }
 585 EXPORT_SYMBOL(drm_gem_object_free);
 586
 587 static void drm_gem_object_ref_bug(struct kref *list_kref)
 588 {
 589         BUG();
 590 }
 591
 592 /**
 593  * Called after the last handle to the object has been closed
 594  *
 595  * Removes any name for the object. Note that this must be
 596  * called before drm_gem_object_free or we'll be touching
 597  * freed memory
 598  */
 599 void drm_gem_object_handle_free(struct drm_gem_object *obj)
 600 {
 601         struct drm_device *dev = obj->dev;
 602
 603         /* Remove any name for this object */
 604         spin_lock(&dev->object_name_lock);
 605         if (obj->name) {
 606                 idr_remove(&dev->object_name_idr, obj->name);
 607                 obj->name = 0;
 608                 spin_unlock(&dev->object_name_lock);
 609                 /*
 610                  * The object name held a reference to this object, drop
 611                  * that now.
 612                 *
 613                 * This cannot be the last reference, since the handle holds one too.
 614                  */
 615                 kref_put(&obj->refcount, drm_gem_object_ref_bug);
 616         } else
 617                 spin_unlock(&dev->object_name_lock);
 618
 619 }
 620 EXPORT_SYMBOL(drm_gem_object_handle_free);
 621
 622 void drm_gem_vm_open(struct vm_area_struct *vma)
 623 {
 624         struct drm_gem_object *obj = vma->vm_private_data;
 625
 626         drm_gem_object_reference(obj);
 627
 628         mutex_lock(&obj->dev->struct_mutex);
 629         drm_vm_open_locked(obj->dev, vma);
 630         mutex_unlock(&obj->dev->struct_mutex);
 631 }
 632 EXPORT_SYMBOL(drm_gem_vm_open);
 633
 634 void drm_gem_vm_close(struct vm_area_struct *vma)
 635 {
 636         struct drm_gem_object *obj = vma->vm_private_data;
 637         struct drm_device *dev = obj->dev;
 638
 639         mutex_lock(&dev->struct_mutex);
 640         drm_vm_close_locked(obj->dev, vma);
 641         drm_gem_object_unreference(obj);
 642         mutex_unlock(&dev->struct_mutex);
 643 }
 644 EXPORT_SYMBOL(drm_gem_vm_close);
 645
 646
 647 /**
 648  * drm_gem_mmap - memory map routine for GEM objects
 649  * @filp: DRM file pointer
 650  * @vma: VMA for the area to be mapped
 651  *
 652  * If a driver supports GEM object mapping, mmap calls on the DRM file
 653  * descriptor will end up here.
 654  *
 655  * If we find the object based on the offset passed in (vma->vm_pgoff will
 656  * contain the fake offset we created when the GTT map ioctl was called on
 657  * the object), we set up the driver fault handler so that any accesses
 658  * to the object can be trapped, to perform migration, GTT binding, surface
 659  * register allocation, or performance monitoring.
 660  */
 661 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 662 {
 663         struct drm_file *priv = filp->private_data;
 664         struct drm_device *dev = priv->minor->dev;
 665         struct drm_gem_mm *mm = dev->mm_private;
 666         struct drm_local_map *map = NULL;
 667         struct drm_gem_object *obj;
 668         struct drm_hash_item *hash;
 669         int ret = 0;
 670
 671         if (drm_device_is_unplugged(dev))
 672                 return -ENODEV;
 673
 674         mutex_lock(&dev->struct_mutex);
 675
 676         if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
 677                 mutex_unlock(&dev->struct_mutex);
 678                 return drm_mmap(filp, vma);
 679         }
 680
 681         map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
 682         if (!map ||
 683             ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
 684                 ret =  -EPERM;
 685                 goto out_unlock;
 686         }
 687
 688         /* Check for valid size. */
 689         if (map->size < vma->vm_end - vma->vm_start) {
 690                 ret = -EINVAL;
 691                 goto out_unlock;
 692         }
 693
 694         obj = map->handle;
 695         if (!obj->dev->driver->gem_vm_ops) {
 696                 ret = -EINVAL;
 697                 goto out_unlock;
 698         }
 699
 700         vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
 701         vma->vm_ops = obj->dev->driver->gem_vm_ops;
 702         vma->vm_private_data = map->handle;
 703         vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 704
 705         /* Take a ref for this mapping of the object, so that the fault
 706          * handler can dereference the mmap offset's pointer to the object.
 707          * This reference is cleaned up by the corresponding vm_close
 708          * (which should happen whether the vma was created by this call, or
 709          * by a vm_open due to mremap or partial unmap or whatever).
 710          */
 711         drm_gem_object_reference(obj);
 712
 713         drm_vm_open_locked(dev, vma);
 714
 715 out_unlock:
 716         mutex_unlock(&dev->struct_mutex);
 717
 718         return ret;
 719 }
 720 EXPORT_SYMBOL(drm_gem_mmap);