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
 276         if (ret != 0)
 277                 return ret;
 278
 279         drm_gem_object_handle_reference(obj);
 280
 281         if (dev->driver->gem_open_object) {
 282                 ret = dev->driver->gem_open_object(obj, file_priv);
 283                 if (ret) {
 284                         drm_gem_handle_delete(file_priv, *handlep);
 285                         return ret;
 286                 }
 287         }
 288
 289         return 0;
 290 }
 291 EXPORT_SYMBOL(drm_gem_handle_create);
 292
 293
 294 /**
 295  * drm_gem_free_mmap_offset - release a fake mmap offset for an object
 296  * @obj: obj in question
 297  *
 298  * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
 299  */
 300 void
 301 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
 302 {
 303         struct drm_device *dev = obj->dev;
 304         struct drm_gem_mm *mm = dev->mm_private;
 305         struct drm_map_list *list = &obj->map_list;
 306
 307         drm_ht_remove_item(&mm->offset_hash, &list->hash);
 308         drm_mm_put_block(list->file_offset_node);
 309         kfree(list->map);
 310         list->map = NULL;
 311 }
 312 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
 313
 314 /**
 315  * drm_gem_create_mmap_offset - create a fake mmap offset for an object
 316  * @obj: obj in question
 317  *
 318  * GEM memory mapping works by handing back to userspace a fake mmap offset
 319  * it can use in a subsequent mmap(2) call.  The DRM core code then looks
 320  * up the object based on the offset and sets up the various memory mapping
 321  * structures.
 322  *
 323  * This routine allocates and attaches a fake offset for @obj.
 324  */
 325 int
 326 drm_gem_create_mmap_offset(struct drm_gem_object *obj)
 327 {
 328         struct drm_device *dev = obj->dev;
 329         struct drm_gem_mm *mm = dev->mm_private;
 330         struct drm_map_list *list;
 331         struct drm_local_map *map;
 332         int ret = 0;
 333
 334         /* Set the object up for mmap'ing */
 335         list = &obj->map_list;
 336         list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL);
 337         if (!list->map)
 338                 return -ENOMEM;
 339
 340         map = list->map;
 341         map->type = _DRM_GEM;
 342         map->size = obj->size;
 343         map->handle = obj;
 344
 345         /* Get a DRM GEM mmap offset allocated... */
 346         list->file_offset_node = drm_mm_search_free(&mm->offset_manager,
 347                         obj->size / PAGE_SIZE, 0, 0);
 348
 349         if (!list->file_offset_node) {
 350                 DRM_ERROR("failed to allocate offset for bo %d\n", obj->name);
 351                 ret = -ENOSPC;
 352                 goto out_free_list;
 353         }
 354
 355         list->file_offset_node = drm_mm_get_block(list->file_offset_node,
 356                         obj->size / PAGE_SIZE, 0);
 357         if (!list->file_offset_node) {
 358                 ret = -ENOMEM;
 359                 goto out_free_list;
 360         }
 361
 362         list->hash.key = list->file_offset_node->start;
 363         ret = drm_ht_insert_item(&mm->offset_hash, &list->hash);
 364         if (ret) {
 365                 DRM_ERROR("failed to add to map hash\n");
 366                 goto out_free_mm;
 367         }
 368
 369         return 0;
 370
 371 out_free_mm:
 372         drm_mm_put_block(list->file_offset_node);
 373 out_free_list:
 374         kfree(list->map);
 375         list->map = NULL;
 376
 377         return ret;
 378 }
 379 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
 380
 381 /** Returns a reference to the object named by the handle. */
 382 struct drm_gem_object *
 383 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
 384                       u32 handle)
 385 {
 386         struct drm_gem_object *obj;
 387
 388         spin_lock(&filp->table_lock);
 389
 390         /* Check if we currently have a reference on the object */
 391         obj = idr_find(&filp->object_idr, handle);
 392         if (obj == NULL) {
 393                 spin_unlock(&filp->table_lock);
 394                 return NULL;
 395         }
 396
 397         drm_gem_object_reference(obj);
 398
 399         spin_unlock(&filp->table_lock);
 400
 401         return obj;
 402 }
 403 EXPORT_SYMBOL(drm_gem_object_lookup);
 404
 405 /**
 406  * Releases the handle to an mm object.
 407  */
 408 int
 409 drm_gem_close_ioctl(struct drm_device *dev, void *data,
 410                     struct drm_file *file_priv)
 411 {
 412         struct drm_gem_close *args = data;
 413         int ret;
 414
 415         if (!(dev->driver->driver_features & DRIVER_GEM))
 416                 return -ENODEV;
 417
 418         ret = drm_gem_handle_delete(file_priv, args->handle);
 419
 420         return ret;
 421 }
 422
 423 /**
 424  * Create a global name for an object, returning the name.
 425  *
 426  * Note that the name does not hold a reference; when the object
 427  * is freed, the name goes away.
 428  */
 429 int
 430 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
 431                     struct drm_file *file_priv)
 432 {
 433         struct drm_gem_flink *args = data;
 434         struct drm_gem_object *obj;
 435         int ret;
 436
 437         if (!(dev->driver->driver_features & DRIVER_GEM))
 438                 return -ENODEV;
 439
 440         obj = drm_gem_object_lookup(dev, file_priv, args->handle);
 441         if (obj == NULL)
 442                 return -ENOENT;
 443
 444 again:
 445         if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0) {
 446                 ret = -ENOMEM;
 447                 goto err;
 448         }
 449
 450         spin_lock(&dev->object_name_lock);
 451         if (!obj->name) {
 452                 ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
 453                                         &obj->name);
 454                 args->name = (uint64_t) obj->name;
 455                 spin_unlock(&dev->object_name_lock);
 456
 457                 if (ret == -EAGAIN)
 458                         goto again;
 459
 460                 if (ret != 0)
 461                         goto err;
 462
 463                 /* Allocate a reference for the name table.  */
 464                 drm_gem_object_reference(obj);
 465         } else {
 466                 args->name = (uint64_t) obj->name;
 467                 spin_unlock(&dev->object_name_lock);
 468                 ret = 0;
 469         }
 470
 471 err:
 472         drm_gem_object_unreference_unlocked(obj);
 473         return ret;
 474 }
 475
 476 /**
 477  * Open an object using the global name, returning a handle and the size.
 478  *
 479  * This handle (of course) holds a reference to the object, so the object
 480  * will not go away until the handle is deleted.
 481  */
 482 int
 483 drm_gem_open_ioctl(struct drm_device *dev, void *data,
 484                    struct drm_file *file_priv)
 485 {
 486         struct drm_gem_open *args = data;
 487         struct drm_gem_object *obj;
 488         int ret;
 489         u32 handle;
 490
 491         if (!(dev->driver->driver_features & DRIVER_GEM))
 492                 return -ENODEV;
 493
 494         spin_lock(&dev->object_name_lock);
 495         obj = idr_find(&dev->object_name_idr, (int) args->name);
 496         if (obj)
 497                 drm_gem_object_reference(obj);
 498         spin_unlock(&dev->object_name_lock);
 499         if (!obj)
 500                 return -ENOENT;
 501
 502         ret = drm_gem_handle_create(file_priv, obj, &handle);
 503         drm_gem_object_unreference_unlocked(obj);
 504         if (ret)
 505                 return ret;
 506
 507         args->handle = handle;
 508         args->size = obj->size;
 509
 510         return 0;
 511 }
 512
 513 /**
 514  * Called at device open time, sets up the structure for handling refcounting
 515  * of mm objects.
 516  */
 517 void
 518 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
 519 {
 520         idr_init(&file_private->object_idr);
 521         spin_lock_init(&file_private->table_lock);
 522 }
 523
 524 /**
 525  * Called at device close to release the file's
 526  * handle references on objects.
 527  */
 528 static int
 529 drm_gem_object_release_handle(int id, void *ptr, void *data)
 530 {
 531         struct drm_file *file_priv = data;
 532         struct drm_gem_object *obj = ptr;
 533         struct drm_device *dev = obj->dev;
 534
 535         if (obj->import_attach)
 536                 drm_prime_remove_imported_buf_handle(&file_priv->prime,
 537                                 obj->import_attach->dmabuf);
 538
 539         if (dev->driver->gem_close_object)
 540                 dev->driver->gem_close_object(obj, file_priv);
 541
 542         drm_gem_object_handle_unreference_unlocked(obj);
 543
 544         return 0;
 545 }
 546
 547 /**
 548  * Called at close time when the filp is going away.
 549  *
 550  * Releases any remaining references on objects by this filp.
 551  */
 552 void
 553 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
 554 {
 555         idr_for_each(&file_private->object_idr,
 556                      &drm_gem_object_release_handle, file_private);
 557
 558         idr_remove_all(&file_private->object_idr);
 559         idr_destroy(&file_private->object_idr);
 560 }
 561
 562 void
 563 drm_gem_object_release(struct drm_gem_object *obj)
 564 {
 565         if (obj->filp)
 566             fput(obj->filp);
 567 }
 568 EXPORT_SYMBOL(drm_gem_object_release);
 569
 570 /**
 571  * Called after the last reference to the object has been lost.
 572  * Must be called holding struct_ mutex
 573  *
 574  * Frees the object
 575  */
 576 void
 577 drm_gem_object_free(struct kref *kref)
 578 {
 579         struct drm_gem_object *obj = (struct drm_gem_object *) kref;
 580         struct drm_device *dev = obj->dev;
 581
 582         BUG_ON(!mutex_is_locked(&dev->struct_mutex));
 583
 584         if (dev->driver->gem_free_object != NULL)
 585                 dev->driver->gem_free_object(obj);
 586 }
 587 EXPORT_SYMBOL(drm_gem_object_free);
 588
 589 static void drm_gem_object_ref_bug(struct kref *list_kref)
 590 {
 591         BUG();
 592 }
 593
 594 /**
 595  * Called after the last handle to the object has been closed
 596  *
 597  * Removes any name for the object. Note that this must be
 598  * called before drm_gem_object_free or we'll be touching
 599  * freed memory
 600  */
 601 void drm_gem_object_handle_free(struct drm_gem_object *obj)
 602 {
 603         struct drm_device *dev = obj->dev;
 604
 605         /* Remove any name for this object */
 606         spin_lock(&dev->object_name_lock);
 607         if (obj->name) {
 608                 idr_remove(&dev->object_name_idr, obj->name);
 609                 obj->name = 0;
 610                 spin_unlock(&dev->object_name_lock);
 611                 /*
 612                  * The object name held a reference to this object, drop
 613                  * that now.
 614                 *
 615                 * This cannot be the last reference, since the handle holds one too.
 616                  */
 617                 kref_put(&obj->refcount, drm_gem_object_ref_bug);
 618         } else
 619                 spin_unlock(&dev->object_name_lock);
 620
 621 }
 622 EXPORT_SYMBOL(drm_gem_object_handle_free);
 623
 624 void drm_gem_vm_open(struct vm_area_struct *vma)
 625 {
 626         struct drm_gem_object *obj = vma->vm_private_data;
 627
 628         drm_gem_object_reference(obj);
 629
 630         mutex_lock(&obj->dev->struct_mutex);
 631         drm_vm_open_locked(vma);
 632         mutex_unlock(&obj->dev->struct_mutex);
 633 }
 634 EXPORT_SYMBOL(drm_gem_vm_open);
 635
 636 void drm_gem_vm_close(struct vm_area_struct *vma)
 637 {
 638         struct drm_gem_object *obj = vma->vm_private_data;
 639         struct drm_device *dev = obj->dev;
 640
 641         mutex_lock(&dev->struct_mutex);
 642         drm_vm_close_locked(vma);
 643         drm_gem_object_unreference(obj);
 644         mutex_unlock(&dev->struct_mutex);
 645 }
 646 EXPORT_SYMBOL(drm_gem_vm_close);
 647
 648
 649 /**
 650  * drm_gem_mmap - memory map routine for GEM objects
 651  * @filp: DRM file pointer
 652  * @vma: VMA for the area to be mapped
 653  *
 654  * If a driver supports GEM object mapping, mmap calls on the DRM file
 655  * descriptor will end up here.
 656  *
 657  * If we find the object based on the offset passed in (vma->vm_pgoff will
 658  * contain the fake offset we created when the GTT map ioctl was called on
 659  * the object), we set up the driver fault handler so that any accesses
 660  * to the object can be trapped, to perform migration, GTT binding, surface
 661  * register allocation, or performance monitoring.
 662  */
 663 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 664 {
 665         struct drm_file *priv = filp->private_data;
 666         struct drm_device *dev = priv->minor->dev;
 667         struct drm_gem_mm *mm = dev->mm_private;
 668         struct drm_local_map *map = NULL;
 669         struct drm_gem_object *obj;
 670         struct drm_hash_item *hash;
 671         int ret = 0;
 672
 673         if (drm_device_is_unplugged(dev))
 674                 return -ENODEV;
 675
 676         mutex_lock(&dev->struct_mutex);
 677
 678         if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
 679                 mutex_unlock(&dev->struct_mutex);
 680                 return drm_mmap(filp, vma);
 681         }
 682
 683         map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
 684         if (!map ||
 685             ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
 686                 ret =  -EPERM;
 687                 goto out_unlock;
 688         }
 689
 690         /* Check for valid size. */
 691         if (map->size < vma->vm_end - vma->vm_start) {
 692                 ret = -EINVAL;
 693                 goto out_unlock;
 694         }
 695
 696         obj = map->handle;
 697         if (!obj->dev->driver->gem_vm_ops) {
 698                 ret = -EINVAL;
 699                 goto out_unlock;
 700         }
 701
 702         vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
 703         vma->vm_ops = obj->dev->driver->gem_vm_ops;
 704         vma->vm_private_data = map->handle;
 705         vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 706
 707         /* Take a ref for this mapping of the object, so that the fault
 708          * handler can dereference the mmap offset's pointer to the object.
 709          * This reference is cleaned up by the corresponding vm_close
 710          * (which should happen whether the vma was created by this call, or
 711          * by a vm_open due to mremap or partial unmap or whatever).
 712          */
 713         drm_gem_object_reference(obj);
 714
 715         drm_vm_open_locked(vma);
 716
 717 out_unlock:
 718         mutex_unlock(&dev->struct_mutex);
 719
 720         return ret;
 721 }
 722 EXPORT_SYMBOL(drm_gem_mmap);