2 * Copyright © 2008 Intel Corporation
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:
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
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
24 * Eric Anholt <eric@anholt.net>
28 * Copyright (c) 2011 The FreeBSD Foundation
29 * All rights reserved.
31 * This software was developed by Konstantin Belousov under sponsorship from
32 * the FreeBSD Foundation.
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
37 * 1. Redistributions of source code must retain the above copyright
38 * notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 * notice, this list of conditions and the following disclaimer in the
41 * documentation and/or other materials provided with the distribution.
43 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/limits.h>
62 #include <sys/mutex.h>
66 #include <vm/vm_page.h>
68 #include <linux/types.h>
70 #include <linux/module.h>
72 #include <drm/drm_vma_manager.h>
73 #include <drm/drm_gem.h>
74 #include "drm_internal.h"
78 * This file provides some of the base ioctls and library routines for
79 * the graphics memory manager implemented by each device driver.
81 * Because various devices have different requirements in terms of
82 * synchronization and migration strategies, implementing that is left up to
83 * the driver, and all that the general API provides should be generic --
84 * allocating objects, reading/writing data with the cpu, freeing objects.
85 * Even there, platform-dependent optimizations for reading/writing data with
86 * the CPU mean we'll likely hook those out to driver-specific calls. However,
87 * the DRI2 implementation wants to have at least allocate/mmap be generic.
89 * The goal was to have swap-backed object allocation managed through
90 * struct file. However, file descriptors as handles to a struct file have
92 * - Process limits prevent more than 1024 or so being used at a time by
94 * - Inability to allocate high fds will aggravate the X Server's select()
95 * handling, and likely that of many GL client applications as well.
97 * This led to a plan of using our own integer IDs (called handles, following
98 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
99 * ioctls. The objects themselves will still include the struct file so
100 * that we can transition to fds if the required kernel infrastructure shows
101 * up at a later date, and as our interface with shmfs for memory allocation.
105 * We make up offsets for buffer objects so we can recognize them at
109 /* pgoff in mmap is an unsigned long, so we need to make sure that
110 * the faked up offset will fit
113 #if BITS_PER_LONG == 64
114 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
115 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
117 #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
118 #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
122 * drm_gem_init - Initialize the GEM device fields
123 * @dev: drm_devic structure to initialize
126 drm_gem_init(struct drm_device
*dev
)
128 struct drm_gem_mm
*mm
;
130 lockinit(&dev
->object_name_lock
, "objnam", 0, LK_CANRECURSE
);
131 idr_init(&dev
->object_name_idr
);
133 mm
= kzalloc(sizeof(struct drm_gem_mm
), GFP_KERNEL
);
135 DRM_ERROR("out of memory\n");
139 dev
->mm_private
= mm
;
141 if (drm_ht_create(&mm
->offset_hash
, 12)) {
146 mm
->idxunr
= new_unrhdr(0, DRM_GEM_MAX_IDX
, NULL
);
147 drm_mm_init(&mm
->offset_manager
, DRM_FILE_PAGE_OFFSET_START
,
148 DRM_FILE_PAGE_OFFSET_SIZE
);
149 drm_vma_offset_manager_init(&mm
->vma_manager
,
150 DRM_FILE_PAGE_OFFSET_START
,
151 DRM_FILE_PAGE_OFFSET_SIZE
);
157 drm_gem_destroy(struct drm_device
*dev
)
159 struct drm_gem_mm
*mm
= dev
->mm_private
;
161 drm_mm_takedown(&mm
->offset_manager
);
162 drm_ht_remove(&mm
->offset_hash
);
164 drm_vma_offset_manager_destroy(&mm
->vma_manager
);
165 delete_unrhdr(mm
->idxunr
);
167 dev
->mm_private
= NULL
;
171 * Initialize an already allocated GEM object of the specified size with
172 * shmfs backing store.
174 int drm_gem_object_init(struct drm_device
*dev
,
175 struct drm_gem_object
*obj
, size_t size
)
177 drm_gem_private_object_init(dev
, obj
, size
);
179 obj
->vm_obj
= default_pager_alloc(NULL
, size
,
180 VM_PROT_READ
| VM_PROT_WRITE
, 0);
184 EXPORT_SYMBOL(drm_gem_object_init
);
187 * drm_gem_object_init - initialize an allocated private GEM object
188 * @dev: drm_device the object should be initialized for
189 * @obj: drm_gem_object to initialize
192 * Initialize an already allocated GEM object of the specified size with
193 * no GEM provided backing store. Instead the caller is responsible for
194 * backing the object and handling it.
196 void drm_gem_private_object_init(struct drm_device
*dev
,
197 struct drm_gem_object
*obj
, size_t size
)
199 BUG_ON((size
& (PAGE_SIZE
- 1)) != 0);
204 kref_init(&obj
->refcount
);
205 obj
->handle_count
= 0;
207 drm_vma_node_reset(&obj
->vma_node
);
209 EXPORT_SYMBOL(drm_gem_private_object_init
);
212 drm_gem_remove_prime_handles(struct drm_gem_object
*obj
, struct drm_file
*filp
)
215 if (obj
->import_attach
) {
216 drm_prime_remove_buf_handle(&filp
->prime
,
217 obj
->import_attach
->dmabuf
);
219 if (obj
->export_dma_buf
) {
220 drm_prime_remove_buf_handle(&filp
->prime
,
221 obj
->export_dma_buf
);
226 static void drm_gem_object_ref_bug(struct kref
*list_kref
)
232 * drm_gem_object_free - release resources bound to userspace handles
233 * @obj: GEM object to clean up.
235 * Called after the last handle to the object has been closed
237 * Removes any name for the object. Note that this must be
238 * called before drm_gem_object_free or we'll be touching
241 static void drm_gem_object_handle_free(struct drm_gem_object
*obj
)
243 struct drm_device
*dev
= obj
->dev
;
245 /* Remove any name for this object */
247 idr_remove(&dev
->object_name_idr
, obj
->name
);
250 * The object name held a reference to this object, drop
253 * This cannot be the last reference, since the handle holds one too.
255 kref_put(&obj
->refcount
, drm_gem_object_ref_bug
);
260 static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object
*obj
)
262 /* Unbreak the reference cycle if we have an exported dma_buf. */
264 dma_buf_put(obj
->dma_buf
);
271 drm_gem_object_handle_unreference_unlocked(struct drm_gem_object
*obj
)
273 if (WARN_ON(obj
->handle_count
== 0))
277 * Must bump handle count first as this may be the last
278 * ref, in which case the object would disappear before we
282 mutex_lock(&obj
->dev
->object_name_lock
);
283 if (--obj
->handle_count
== 0)
284 drm_gem_object_handle_free(obj
);
285 mutex_unlock(&obj
->dev
->object_name_lock
);
287 drm_gem_object_unreference_unlocked(obj
);
291 * Called at device close to release the file's
292 * handle references on objects.
295 drm_gem_object_release_handle(int id
, void *ptr
, void *data
)
297 struct drm_file
*file_priv
= data
;
298 struct drm_gem_object
*obj
= ptr
;
299 struct drm_device
*dev
= obj
->dev
;
301 drm_gem_remove_prime_handles(obj
, file_priv
);
303 if (dev
->driver
->gem_close_object
)
304 dev
->driver
->gem_close_object(obj
, file_priv
);
306 drm_gem_object_handle_unreference_unlocked(obj
);
312 * drm_gem_handle_delete - deletes the given file-private handle
313 * @filp: drm file-private structure to use for the handle look up
314 * @handle: userspace handle to delete
316 * Removes the GEM handle from the @filp lookup table which has been added with
317 * drm_gem_handle_create(). If this is the last handle also cleans up linked
318 * resources like GEM names.
321 drm_gem_handle_delete(struct drm_file
*filp
, u32 handle
)
323 struct drm_device
*dev
;
324 struct drm_gem_object
*obj
;
326 /* This is gross. The idr system doesn't let us try a delete and
327 * return an error code. It just spews if you fail at deleting.
328 * So, we have to grab a lock around finding the object and then
329 * doing the delete on it and dropping the refcount, or the user
330 * could race us to double-decrement the refcount and cause a
331 * use-after-free later. Given the frequency of our handle lookups,
332 * we may want to use ida for number allocation and a hash table
333 * for the pointers, anyway.
335 lockmgr(&filp
->table_lock
, LK_EXCLUSIVE
);
337 /* Check if we currently have a reference on the object */
338 obj
= idr_find(&filp
->object_idr
, handle
);
340 lockmgr(&filp
->table_lock
, LK_RELEASE
);
345 /* Release reference and decrement refcount. */
346 idr_remove(&filp
->object_idr
, handle
);
347 lockmgr(&filp
->table_lock
, LK_RELEASE
);
349 drm_gem_remove_prime_handles(obj
, filp
);
351 if (dev
->driver
->gem_close_object
)
352 dev
->driver
->gem_close_object(obj
, filp
);
353 drm_gem_object_handle_unreference_unlocked(obj
);
357 EXPORT_SYMBOL(drm_gem_handle_delete
);
360 * drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
361 * @file: drm file-private structure to remove the dumb handle from
362 * @dev: corresponding drm_device
363 * @handle: the dumb handle to remove
365 * This implements the ->dumb_destroy kms driver callback for drivers which use
366 * gem to manage their backing storage.
368 int drm_gem_dumb_destroy(struct drm_file
*file
,
369 struct drm_device
*dev
,
372 return drm_gem_handle_delete(file
, handle
);
374 EXPORT_SYMBOL(drm_gem_dumb_destroy
);
377 * drm_gem_handle_create_tail - internal functions to create a handle
378 * @file_priv: drm file-private structure to register the handle for
379 * @obj: object to register
380 * @handlep: pointer to return the created handle to the caller
382 * This expects the dev->object_name_lock to be held already and will drop it
383 * before returning. Used to avoid races in establishing new handles when
384 * importing an object from either an flink name or a dma-buf.
386 * Handles must be release again through drm_gem_handle_delete(). This is done
387 * when userspace closes @file_priv for all attached handles, or through the
388 * GEM_CLOSE ioctl for individual handles.
391 drm_gem_handle_create_tail(struct drm_file
*file_priv
,
392 struct drm_gem_object
*obj
,
395 struct drm_device
*dev
= obj
->dev
;
398 *handlep
= 0; /* whack gcc warning */
399 WARN_ON(!mutex_is_locked(&dev
->object_name_lock
));
402 * Get the user-visible handle using idr. Preload and perform
403 * allocation under our spinlock.
405 idr_preload(GFP_KERNEL
);
406 lockmgr(&file_priv
->table_lock
, LK_EXCLUSIVE
);
408 ret
= idr_alloc(&file_priv
->object_idr
, obj
, 1, 0, GFP_NOWAIT
);
409 drm_gem_object_reference(obj
);
411 lockmgr(&file_priv
->table_lock
, LK_RELEASE
);
413 mutex_unlock(&dev
->object_name_lock
);
415 drm_gem_object_handle_unreference_unlocked(obj
);
421 ret
= drm_vma_node_allow(&obj
->vma_node
, file_priv
->filp
);
423 drm_gem_handle_delete(file_priv
, *handlep
);
428 if (dev
->driver
->gem_open_object
) {
429 ret
= dev
->driver
->gem_open_object(obj
, file_priv
);
431 drm_gem_handle_delete(file_priv
, *handlep
);
440 * drm_gem_handle_create - create a gem handle for an object
441 * @file_priv: drm file-private structure to register the handle for
442 * @obj: object to register
443 * @handlep: pionter to return the created handle to the caller
445 * Create a handle for this object. This adds a handle reference
446 * to the object, which includes a regular reference count. Callers
447 * will likely want to dereference the object afterwards.
449 int drm_gem_handle_create(struct drm_file
*file_priv
,
450 struct drm_gem_object
*obj
,
453 mutex_lock(&obj
->dev
->object_name_lock
);
455 return drm_gem_handle_create_tail(file_priv
, obj
, handlep
);
457 EXPORT_SYMBOL(drm_gem_handle_create
);
460 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
461 * @obj: obj in question
463 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
465 * Note that drm_gem_object_release() already calls this function, so drivers
466 * don't have to take care of releasing the mmap offset themselves when freeing
470 drm_gem_free_mmap_offset(struct drm_gem_object
*obj
)
472 struct drm_device
*dev
= obj
->dev
;
473 struct drm_gem_mm
*mm
= dev
->mm_private
;
474 struct drm_hash_item
*list
;
478 list
= &obj
->map_list
;
480 drm_ht_remove_item(&mm
->offset_hash
, list
);
481 free_unr(mm
->idxunr
, list
->key
);
484 drm_vma_offset_remove(&mm
->vma_manager
, &obj
->vma_node
);
486 EXPORT_SYMBOL(drm_gem_free_mmap_offset
);
489 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
490 * @obj: obj in question
491 * @size: the virtual size
493 * GEM memory mapping works by handing back to userspace a fake mmap offset
494 * it can use in a subsequent mmap(2) call. The DRM core code then looks
495 * up the object based on the offset and sets up the various memory mapping
498 * This routine allocates and attaches a fake offset for @obj, in cases where
499 * the virtual size differs from the physical size (ie. obj->size). Otherwise
500 * just use drm_gem_create_mmap_offset().
502 * This function is idempotent and handles an already allocated mmap offset
503 * transparently. Drivers do not need to check for this case.
506 drm_gem_create_mmap_offset_size(struct drm_gem_object
*obj
, size_t size
)
508 struct drm_device
*dev
= obj
->dev
;
509 struct drm_gem_mm
*mm
= dev
->mm_private
;
515 obj
->map_list
.key
= alloc_unr(mm
->idxunr
);
516 ret
= drm_ht_insert_item(&mm
->offset_hash
, &obj
->map_list
);
518 DRM_ERROR("failed to add to map hash\n");
519 free_unr(mm
->idxunr
, obj
->map_list
.key
);
525 return drm_vma_offset_add(&mm
->vma_manager
, &obj
->vma_node
,
528 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size
);
531 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
532 * @obj: obj in question
534 * GEM memory mapping works by handing back to userspace a fake mmap offset
535 * it can use in a subsequent mmap(2) call. The DRM core code then looks
536 * up the object based on the offset and sets up the various memory mapping
539 * This routine allocates and attaches a fake offset for @obj.
541 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
542 * the fake offset again.
544 int drm_gem_create_mmap_offset(struct drm_gem_object
*obj
)
546 return drm_gem_create_mmap_offset_size(obj
, obj
->size
);
548 EXPORT_SYMBOL(drm_gem_create_mmap_offset
);
551 * drm_gem_object_lookup - look up a GEM object from it's handle
553 * @filp: DRM file private date
554 * @handle: userspace handle
558 * A reference to the object named by the handle if such exists on @filp, NULL
561 struct drm_gem_object
*
562 drm_gem_object_lookup(struct drm_file
*filp
, u32 handle
)
564 struct drm_gem_object
*obj
;
566 lockmgr(&filp
->table_lock
, LK_EXCLUSIVE
);
568 /* Check if we currently have a reference on the object */
569 obj
= idr_find(&filp
->object_idr
, handle
);
571 lockmgr(&filp
->table_lock
, LK_RELEASE
);
575 drm_gem_object_reference(obj
);
577 lockmgr(&filp
->table_lock
, LK_RELEASE
);
581 EXPORT_SYMBOL(drm_gem_object_lookup
);
584 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
587 * @file_priv: drm file-private structure
589 * Releases the handle to an mm object.
592 drm_gem_close_ioctl(struct drm_device
*dev
, void *data
,
593 struct drm_file
*file_priv
)
595 struct drm_gem_close
*args
= data
;
598 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
601 ret
= drm_gem_handle_delete(file_priv
, args
->handle
);
607 * Create a global name for an object, returning the name.
609 * Note that the name does not hold a reference; when the object
610 * is freed, the name goes away.
613 drm_gem_flink_ioctl(struct drm_device
*dev
, void *data
,
614 struct drm_file
*file_priv
)
616 struct drm_gem_flink
*args
= data
;
617 struct drm_gem_object
*obj
;
620 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
623 obj
= drm_gem_object_lookup(file_priv
, args
->handle
);
627 idr_preload(GFP_KERNEL
);
628 lockmgr(&dev
->object_name_lock
, LK_EXCLUSIVE
);
629 /* prevent races with concurrent gem_close. */
630 if (obj
->handle_count
== 0) {
636 ret
= idr_alloc(&dev
->object_name_idr
, obj
, 1, 0, GFP_NOWAIT
);
642 /* Allocate a reference for the name table. */
643 drm_gem_object_reference(obj
);
646 args
->name
= (uint64_t) obj
->name
;
650 lockmgr(&dev
->object_name_lock
, LK_RELEASE
);
652 drm_gem_object_unreference_unlocked(obj
);
657 * drm_gem_open - implementation of the GEM_OPEN ioctl
660 * @file_priv: drm file-private structure
662 * Open an object using the global name, returning a handle and the size.
664 * This handle (of course) holds a reference to the object, so the object
665 * will not go away until the handle is deleted.
668 drm_gem_open_ioctl(struct drm_device
*dev
, void *data
,
669 struct drm_file
*file_priv
)
671 struct drm_gem_open
*args
= data
;
672 struct drm_gem_object
*obj
;
676 if (!drm_core_check_feature(dev
, DRIVER_GEM
))
679 lockmgr(&dev
->object_name_lock
, LK_EXCLUSIVE
);
680 obj
= idr_find(&dev
->object_name_idr
, (int) args
->name
);
682 drm_gem_object_reference(obj
);
683 lockmgr(&dev
->object_name_lock
, LK_RELEASE
);
687 ret
= drm_gem_handle_create(file_priv
, obj
, &handle
);
688 drm_gem_object_unreference_unlocked(obj
);
692 args
->handle
= handle
;
693 args
->size
= obj
->size
;
699 * gem_gem_open - initalizes GEM file-private structures at devnode open time
700 * @dev: drm_device which is being opened by userspace
701 * @file_private: drm file-private structure to set up
703 * Called at device open time, sets up the structure for handling refcounting
707 drm_gem_open(struct drm_device
*dev
, struct drm_file
*file_private
)
709 idr_init(&file_private
->object_idr
);
710 lockinit(&file_private
->table_lock
, "fptab", 0, LK_CANRECURSE
);
714 * drm_gem_release - release file-private GEM resources
715 * @dev: drm_device which is being closed by userspace
716 * @file_private: drm file-private structure to clean up
718 * Called at close time when the filp is going away.
720 * Releases any remaining references on objects by this filp.
723 drm_gem_release(struct drm_device
*dev
, struct drm_file
*file_private
)
725 idr_for_each(&file_private
->object_idr
,
726 &drm_gem_object_release_handle
, file_private
);
727 idr_destroy(&file_private
->object_idr
);
731 * drm_gem_object_release - release GEM buffer object resources
732 * @obj: GEM buffer object
734 * This releases any structures and resources used by @obj and is the invers of
735 * drm_gem_object_init().
738 drm_gem_object_release(struct drm_gem_object
*obj
)
742 * obj->vm_obj can be NULL for private gem objects.
744 vm_object_deallocate(obj
->vm_obj
);
746 EXPORT_SYMBOL(drm_gem_object_release
);
749 * drm_gem_object_free - free a GEM object
750 * @kref: kref of the object to free
752 * Called after the last reference to the object has been lost.
753 * Must be called holding struct_ mutex
758 drm_gem_object_free(struct kref
*kref
)
760 struct drm_gem_object
*obj
=
761 container_of(kref
, struct drm_gem_object
, refcount
);
762 struct drm_device
*dev
= obj
->dev
;
764 WARN_ON(!mutex_is_locked(&dev
->struct_mutex
));
766 if (dev
->driver
->gem_free_object
!= NULL
)
767 dev
->driver
->gem_free_object(obj
);
769 EXPORT_SYMBOL(drm_gem_object_free
);
771 static struct drm_gem_object
*
772 drm_gem_object_from_offset(struct drm_device
*dev
, vm_ooffset_t offset
)
774 struct drm_gem_object
*obj
;
775 struct drm_gem_mm
*mm
= dev
->mm_private
;
776 struct drm_hash_item
*hash
;
778 if ((offset
& DRM_GEM_MAPPING_MASK
) != DRM_GEM_MAPPING_KEY
)
780 offset
&= ~DRM_GEM_MAPPING_KEY
;
782 if (drm_ht_find_item(&mm
->offset_hash
, DRM_GEM_MAPPING_IDX(offset
),
786 obj
= container_of(hash
, struct drm_gem_object
, map_list
);
791 drm_gem_mmap_single(struct drm_device
*dev
, vm_ooffset_t
*offset
, vm_size_t size
,
792 struct vm_object
**obj_res
, int nprot
)
794 struct drm_gem_object
*gem_obj
;
795 struct vm_object
*vm_obj
;
798 gem_obj
= drm_gem_object_from_offset(dev
, *offset
);
799 if (gem_obj
== NULL
) {
804 drm_gem_object_reference(gem_obj
);
806 vm_obj
= cdev_pager_allocate(gem_obj
, OBJT_MGTDEVICE
,
807 dev
->driver
->gem_pager_ops
, size
, nprot
,
808 DRM_GEM_MAPPING_MAPOFF(*offset
), curthread
->td_ucred
);
809 if (vm_obj
== NULL
) {
810 drm_gem_object_unreference_unlocked(gem_obj
);
813 *offset
= DRM_GEM_MAPPING_MAPOFF(*offset
);