Merge tag 'drm-misc-next-fixes-2020-08-05' of git://anongit.freedesktop.org/drm/drm...
[linux-2.6-microblaze.git] / drivers / gpu / drm / ttm / ttm_bo_vm.c
1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
2 /**************************************************************************
3  *
4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
5  * All Rights Reserved.
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a
8  * copy of this software and associated documentation files (the
9  * "Software"), to deal in the Software without restriction, including
10  * without limitation the rights to use, copy, modify, merge, publish,
11  * distribute, sub license, and/or sell copies of the Software, and to
12  * permit persons to whom the Software is furnished to do so, subject to
13  * the following conditions:
14  *
15  * The above copyright notice and this permission notice (including the
16  * next paragraph) shall be included in all copies or substantial portions
17  * of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
26  *
27  **************************************************************************/
28 /*
29  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
30  */
31
32 #define pr_fmt(fmt) "[TTM] " fmt
33
34 #include <drm/ttm/ttm_module.h>
35 #include <drm/ttm/ttm_bo_driver.h>
36 #include <drm/ttm/ttm_placement.h>
37 #include <drm/drm_vma_manager.h>
38 #include <linux/mm.h>
39 #include <linux/pfn_t.h>
40 #include <linux/rbtree.h>
41 #include <linux/module.h>
42 #include <linux/uaccess.h>
43 #include <linux/mem_encrypt.h>
44
45 static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo,
46                                 struct vm_fault *vmf)
47 {
48         vm_fault_t ret = 0;
49         int err = 0;
50
51         if (likely(!bo->moving))
52                 goto out_unlock;
53
54         /*
55          * Quick non-stalling check for idle.
56          */
57         if (dma_fence_is_signaled(bo->moving))
58                 goto out_clear;
59
60         /*
61          * If possible, avoid waiting for GPU with mmap_lock
62          * held.  We only do this if the fault allows retry and this
63          * is the first attempt.
64          */
65         if (fault_flag_allow_retry_first(vmf->flags)) {
66                 ret = VM_FAULT_RETRY;
67                 if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
68                         goto out_unlock;
69
70                 ttm_bo_get(bo);
71                 mmap_read_unlock(vmf->vma->vm_mm);
72                 (void) dma_fence_wait(bo->moving, true);
73                 dma_resv_unlock(bo->base.resv);
74                 ttm_bo_put(bo);
75                 goto out_unlock;
76         }
77
78         /*
79          * Ordinary wait.
80          */
81         err = dma_fence_wait(bo->moving, true);
82         if (unlikely(err != 0)) {
83                 ret = (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS :
84                         VM_FAULT_NOPAGE;
85                 goto out_unlock;
86         }
87
88 out_clear:
89         dma_fence_put(bo->moving);
90         bo->moving = NULL;
91
92 out_unlock:
93         return ret;
94 }
95
96 static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
97                                        unsigned long page_offset)
98 {
99         struct ttm_bo_device *bdev = bo->bdev;
100
101         if (bdev->driver->io_mem_pfn)
102                 return bdev->driver->io_mem_pfn(bo, page_offset);
103
104         return ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT)
105                 + page_offset;
106 }
107
108 /**
109  * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback
110  * @bo: The buffer object
111  * @vmf: The fault structure handed to the callback
112  *
113  * vm callbacks like fault() and *_mkwrite() allow for the mm_sem to be dropped
114  * during long waits, and after the wait the callback will be restarted. This
115  * is to allow other threads using the same virtual memory space concurrent
116  * access to map(), unmap() completely unrelated buffer objects. TTM buffer
117  * object reservations sometimes wait for GPU and should therefore be
118  * considered long waits. This function reserves the buffer object interruptibly
119  * taking this into account. Starvation is avoided by the vm system not
120  * allowing too many repeated restarts.
121  * This function is intended to be used in customized fault() and _mkwrite()
122  * handlers.
123  *
124  * Return:
125  *    0 on success and the bo was reserved.
126  *    VM_FAULT_RETRY if blocking wait.
127  *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed.
128  */
129 vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
130                              struct vm_fault *vmf)
131 {
132         /*
133          * Work around locking order reversal in fault / nopfn
134          * between mmap_lock and bo_reserve: Perform a trylock operation
135          * for reserve, and if it fails, retry the fault after waiting
136          * for the buffer to become unreserved.
137          */
138         if (unlikely(!dma_resv_trylock(bo->base.resv))) {
139                 /*
140                  * If the fault allows retry and this is the first
141                  * fault attempt, we try to release the mmap_lock
142                  * before waiting
143                  */
144                 if (fault_flag_allow_retry_first(vmf->flags)) {
145                         if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
146                                 ttm_bo_get(bo);
147                                 mmap_read_unlock(vmf->vma->vm_mm);
148                                 if (!dma_resv_lock_interruptible(bo->base.resv,
149                                                                  NULL))
150                                         dma_resv_unlock(bo->base.resv);
151                                 ttm_bo_put(bo);
152                         }
153
154                         return VM_FAULT_RETRY;
155                 }
156
157                 if (dma_resv_lock_interruptible(bo->base.resv, NULL))
158                         return VM_FAULT_NOPAGE;
159         }
160
161         return 0;
162 }
163 EXPORT_SYMBOL(ttm_bo_vm_reserve);
164
165 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
166 /**
167  * ttm_bo_vm_insert_huge - Insert a pfn for PUD or PMD faults
168  * @vmf: Fault data
169  * @bo: The buffer object
170  * @page_offset: Page offset from bo start
171  * @fault_page_size: The size of the fault in pages.
172  * @pgprot: The page protections.
173  * Does additional checking whether it's possible to insert a PUD or PMD
174  * pfn and performs the insertion.
175  *
176  * Return: VM_FAULT_NOPAGE on successful insertion, VM_FAULT_FALLBACK if
177  * a huge fault was not possible, or on insertion error.
178  */
179 static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf,
180                                         struct ttm_buffer_object *bo,
181                                         pgoff_t page_offset,
182                                         pgoff_t fault_page_size,
183                                         pgprot_t pgprot)
184 {
185         pgoff_t i;
186         vm_fault_t ret;
187         unsigned long pfn;
188         pfn_t pfnt;
189         struct ttm_tt *ttm = bo->ttm;
190         bool write = vmf->flags & FAULT_FLAG_WRITE;
191
192         /* Fault should not cross bo boundary. */
193         page_offset &= ~(fault_page_size - 1);
194         if (page_offset + fault_page_size > bo->num_pages)
195                 goto out_fallback;
196
197         if (bo->mem.bus.is_iomem)
198                 pfn = ttm_bo_io_mem_pfn(bo, page_offset);
199         else
200                 pfn = page_to_pfn(ttm->pages[page_offset]);
201
202         /* pfn must be fault_page_size aligned. */
203         if ((pfn & (fault_page_size - 1)) != 0)
204                 goto out_fallback;
205
206         /* Check that memory is contiguous. */
207         if (!bo->mem.bus.is_iomem) {
208                 for (i = 1; i < fault_page_size; ++i) {
209                         if (page_to_pfn(ttm->pages[page_offset + i]) != pfn + i)
210                                 goto out_fallback;
211                 }
212         } else if (bo->bdev->driver->io_mem_pfn) {
213                 for (i = 1; i < fault_page_size; ++i) {
214                         if (ttm_bo_io_mem_pfn(bo, page_offset + i) != pfn + i)
215                                 goto out_fallback;
216                 }
217         }
218
219         pfnt = __pfn_to_pfn_t(pfn, PFN_DEV);
220         if (fault_page_size == (HPAGE_PMD_SIZE >> PAGE_SHIFT))
221                 ret = vmf_insert_pfn_pmd_prot(vmf, pfnt, pgprot, write);
222 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
223         else if (fault_page_size == (HPAGE_PUD_SIZE >> PAGE_SHIFT))
224                 ret = vmf_insert_pfn_pud_prot(vmf, pfnt, pgprot, write);
225 #endif
226         else
227                 WARN_ON_ONCE(ret = VM_FAULT_FALLBACK);
228
229         if (ret != VM_FAULT_NOPAGE)
230                 goto out_fallback;
231
232         return VM_FAULT_NOPAGE;
233 out_fallback:
234         count_vm_event(THP_FAULT_FALLBACK);
235         return VM_FAULT_FALLBACK;
236 }
237 #else
238 static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf,
239                                         struct ttm_buffer_object *bo,
240                                         pgoff_t page_offset,
241                                         pgoff_t fault_page_size,
242                                         pgprot_t pgprot)
243 {
244         return VM_FAULT_FALLBACK;
245 }
246 #endif
247
248 /**
249  * ttm_bo_vm_fault_reserved - TTM fault helper
250  * @vmf: The struct vm_fault given as argument to the fault callback
251  * @prot: The page protection to be used for this memory area.
252  * @num_prefault: Maximum number of prefault pages. The caller may want to
253  * specify this based on madvice settings and the size of the GPU object
254  * backed by the memory.
255  * @fault_page_size: The size of the fault in pages.
256  *
257  * This function inserts one or more page table entries pointing to the
258  * memory backing the buffer object, and then returns a return code
259  * instructing the caller to retry the page access.
260  *
261  * Return:
262  *   VM_FAULT_NOPAGE on success or pending signal
263  *   VM_FAULT_SIGBUS on unspecified error
264  *   VM_FAULT_OOM on out-of-memory
265  *   VM_FAULT_RETRY if retryable wait
266  */
267 vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
268                                     pgprot_t prot,
269                                     pgoff_t num_prefault,
270                                     pgoff_t fault_page_size)
271 {
272         struct vm_area_struct *vma = vmf->vma;
273         struct ttm_buffer_object *bo = vma->vm_private_data;
274         struct ttm_bo_device *bdev = bo->bdev;
275         unsigned long page_offset;
276         unsigned long page_last;
277         unsigned long pfn;
278         struct ttm_tt *ttm = NULL;
279         struct page *page;
280         int err;
281         pgoff_t i;
282         vm_fault_t ret = VM_FAULT_NOPAGE;
283         unsigned long address = vmf->address;
284         struct ttm_mem_type_manager *man =
285                 &bdev->man[bo->mem.mem_type];
286
287         /*
288          * Refuse to fault imported pages. This should be handled
289          * (if at all) by redirecting mmap to the exporter.
290          */
291         if (bo->ttm && (bo->ttm->page_flags & TTM_PAGE_FLAG_SG))
292                 return VM_FAULT_SIGBUS;
293
294         if (bdev->driver->fault_reserve_notify) {
295                 struct dma_fence *moving = dma_fence_get(bo->moving);
296
297                 err = bdev->driver->fault_reserve_notify(bo);
298                 switch (err) {
299                 case 0:
300                         break;
301                 case -EBUSY:
302                 case -ERESTARTSYS:
303                         dma_fence_put(moving);
304                         return VM_FAULT_NOPAGE;
305                 default:
306                         dma_fence_put(moving);
307                         return VM_FAULT_SIGBUS;
308                 }
309
310                 if (bo->moving != moving) {
311                         spin_lock(&ttm_bo_glob.lru_lock);
312                         ttm_bo_move_to_lru_tail(bo, NULL);
313                         spin_unlock(&ttm_bo_glob.lru_lock);
314                 }
315                 dma_fence_put(moving);
316         }
317
318         /*
319          * Wait for buffer data in transit, due to a pipelined
320          * move.
321          */
322         ret = ttm_bo_vm_fault_idle(bo, vmf);
323         if (unlikely(ret != 0))
324                 return ret;
325
326         err = ttm_mem_io_lock(man, true);
327         if (unlikely(err != 0))
328                 return VM_FAULT_NOPAGE;
329         err = ttm_mem_io_reserve_vm(bo);
330         if (unlikely(err != 0)) {
331                 ret = VM_FAULT_SIGBUS;
332                 goto out_io_unlock;
333         }
334
335         page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
336                 vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node);
337         page_last = vma_pages(vma) + vma->vm_pgoff -
338                 drm_vma_node_start(&bo->base.vma_node);
339
340         if (unlikely(page_offset >= bo->num_pages)) {
341                 ret = VM_FAULT_SIGBUS;
342                 goto out_io_unlock;
343         }
344
345         prot = ttm_io_prot(bo->mem.placement, prot);
346         if (!bo->mem.bus.is_iomem) {
347                 struct ttm_operation_ctx ctx = {
348                         .interruptible = false,
349                         .no_wait_gpu = false,
350                         .flags = TTM_OPT_FLAG_FORCE_ALLOC
351
352                 };
353
354                 if (ttm_tt_create(bo, true)) {
355                         ret = VM_FAULT_OOM;
356                         goto out_io_unlock;
357                 }
358
359                 ttm = bo->ttm;
360                 if (ttm_tt_populate(bo->ttm, &ctx)) {
361                         ret = VM_FAULT_OOM;
362                         goto out_io_unlock;
363                 }
364         } else {
365                 /* Iomem should not be marked encrypted */
366                 prot = pgprot_decrypted(prot);
367         }
368
369         /* We don't prefault on huge faults. Yet. */
370         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && fault_page_size != 1) {
371                 ret = ttm_bo_vm_insert_huge(vmf, bo, page_offset,
372                                             fault_page_size, prot);
373                 goto out_io_unlock;
374         }
375
376         /*
377          * Speculatively prefault a number of pages. Only error on
378          * first page.
379          */
380         for (i = 0; i < num_prefault; ++i) {
381                 if (bo->mem.bus.is_iomem) {
382                         pfn = ttm_bo_io_mem_pfn(bo, page_offset);
383                 } else {
384                         page = ttm->pages[page_offset];
385                         if (unlikely(!page && i == 0)) {
386                                 ret = VM_FAULT_OOM;
387                                 goto out_io_unlock;
388                         } else if (unlikely(!page)) {
389                                 break;
390                         }
391                         page->index = drm_vma_node_start(&bo->base.vma_node) +
392                                 page_offset;
393                         pfn = page_to_pfn(page);
394                 }
395
396                 /*
397                  * Note that the value of @prot at this point may differ from
398                  * the value of @vma->vm_page_prot in the caching- and
399                  * encryption bits. This is because the exact location of the
400                  * data may not be known at mmap() time and may also change
401                  * at arbitrary times while the data is mmap'ed.
402                  * See vmf_insert_mixed_prot() for a discussion.
403                  */
404                 if (vma->vm_flags & VM_MIXEDMAP)
405                         ret = vmf_insert_mixed_prot(vma, address,
406                                                     __pfn_to_pfn_t(pfn, PFN_DEV),
407                                                     prot);
408                 else
409                         ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
410
411                 /* Never error on prefaulted PTEs */
412                 if (unlikely((ret & VM_FAULT_ERROR))) {
413                         if (i == 0)
414                                 goto out_io_unlock;
415                         else
416                                 break;
417                 }
418
419                 address += PAGE_SIZE;
420                 if (unlikely(++page_offset >= page_last))
421                         break;
422         }
423         ret = VM_FAULT_NOPAGE;
424 out_io_unlock:
425         ttm_mem_io_unlock(man);
426         return ret;
427 }
428 EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
429
430 vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
431 {
432         struct vm_area_struct *vma = vmf->vma;
433         pgprot_t prot;
434         struct ttm_buffer_object *bo = vma->vm_private_data;
435         vm_fault_t ret;
436
437         ret = ttm_bo_vm_reserve(bo, vmf);
438         if (ret)
439                 return ret;
440
441         prot = vma->vm_page_prot;
442         ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1);
443         if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
444                 return ret;
445
446         dma_resv_unlock(bo->base.resv);
447
448         return ret;
449 }
450 EXPORT_SYMBOL(ttm_bo_vm_fault);
451
452 void ttm_bo_vm_open(struct vm_area_struct *vma)
453 {
454         struct ttm_buffer_object *bo = vma->vm_private_data;
455
456         WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
457
458         ttm_bo_get(bo);
459 }
460 EXPORT_SYMBOL(ttm_bo_vm_open);
461
462 void ttm_bo_vm_close(struct vm_area_struct *vma)
463 {
464         struct ttm_buffer_object *bo = vma->vm_private_data;
465
466         ttm_bo_put(bo);
467         vma->vm_private_data = NULL;
468 }
469 EXPORT_SYMBOL(ttm_bo_vm_close);
470
471 static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
472                                  unsigned long offset,
473                                  uint8_t *buf, int len, int write)
474 {
475         unsigned long page = offset >> PAGE_SHIFT;
476         unsigned long bytes_left = len;
477         int ret;
478
479         /* Copy a page at a time, that way no extra virtual address
480          * mapping is needed
481          */
482         offset -= page << PAGE_SHIFT;
483         do {
484                 unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
485                 struct ttm_bo_kmap_obj map;
486                 void *ptr;
487                 bool is_iomem;
488
489                 ret = ttm_bo_kmap(bo, page, 1, &map);
490                 if (ret)
491                         return ret;
492
493                 ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
494                 WARN_ON_ONCE(is_iomem);
495                 if (write)
496                         memcpy(ptr, buf, bytes);
497                 else
498                         memcpy(buf, ptr, bytes);
499                 ttm_bo_kunmap(&map);
500
501                 page++;
502                 buf += bytes;
503                 bytes_left -= bytes;
504                 offset = 0;
505         } while (bytes_left);
506
507         return len;
508 }
509
510 int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
511                      void *buf, int len, int write)
512 {
513         unsigned long offset = (addr) - vma->vm_start;
514         struct ttm_buffer_object *bo = vma->vm_private_data;
515         int ret;
516
517         if (len < 1 || (offset + len) >> PAGE_SHIFT > bo->num_pages)
518                 return -EIO;
519
520         ret = ttm_bo_reserve(bo, true, false, NULL);
521         if (ret)
522                 return ret;
523
524         switch (bo->mem.mem_type) {
525         case TTM_PL_SYSTEM:
526                 if (unlikely(bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
527                         ret = ttm_tt_swapin(bo->ttm);
528                         if (unlikely(ret != 0))
529                                 return ret;
530                 }
531                 /* fall through */
532         case TTM_PL_TT:
533                 ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
534                 break;
535         default:
536                 if (bo->bdev->driver->access_memory)
537                         ret = bo->bdev->driver->access_memory(
538                                 bo, offset, buf, len, write);
539                 else
540                         ret = -EIO;
541         }
542
543         ttm_bo_unreserve(bo);
544
545         return ret;
546 }
547 EXPORT_SYMBOL(ttm_bo_vm_access);
548
549 static const struct vm_operations_struct ttm_bo_vm_ops = {
550         .fault = ttm_bo_vm_fault,
551         .open = ttm_bo_vm_open,
552         .close = ttm_bo_vm_close,
553         .access = ttm_bo_vm_access,
554 };
555
556 static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
557                                                   unsigned long offset,
558                                                   unsigned long pages)
559 {
560         struct drm_vma_offset_node *node;
561         struct ttm_buffer_object *bo = NULL;
562
563         drm_vma_offset_lock_lookup(bdev->vma_manager);
564
565         node = drm_vma_offset_lookup_locked(bdev->vma_manager, offset, pages);
566         if (likely(node)) {
567                 bo = container_of(node, struct ttm_buffer_object,
568                                   base.vma_node);
569                 bo = ttm_bo_get_unless_zero(bo);
570         }
571
572         drm_vma_offset_unlock_lookup(bdev->vma_manager);
573
574         if (!bo)
575                 pr_err("Could not find buffer object to map\n");
576
577         return bo;
578 }
579
580 static void ttm_bo_mmap_vma_setup(struct ttm_buffer_object *bo, struct vm_area_struct *vma)
581 {
582         vma->vm_ops = &ttm_bo_vm_ops;
583
584         /*
585          * Note: We're transferring the bo reference to
586          * vma->vm_private_data here.
587          */
588
589         vma->vm_private_data = bo;
590
591         /*
592          * We'd like to use VM_PFNMAP on shared mappings, where
593          * (vma->vm_flags & VM_SHARED) != 0, for performance reasons,
594          * but for some reason VM_PFNMAP + x86 PAT + write-combine is very
595          * bad for performance. Until that has been sorted out, use
596          * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719
597          */
598         vma->vm_flags |= VM_MIXEDMAP;
599         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
600 }
601
602 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
603                 struct ttm_bo_device *bdev)
604 {
605         struct ttm_bo_driver *driver;
606         struct ttm_buffer_object *bo;
607         int ret;
608
609         if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET_START))
610                 return -EINVAL;
611
612         bo = ttm_bo_vm_lookup(bdev, vma->vm_pgoff, vma_pages(vma));
613         if (unlikely(!bo))
614                 return -EINVAL;
615
616         driver = bo->bdev->driver;
617         if (unlikely(!driver->verify_access)) {
618                 ret = -EPERM;
619                 goto out_unref;
620         }
621         ret = driver->verify_access(bo, filp);
622         if (unlikely(ret != 0))
623                 goto out_unref;
624
625         ttm_bo_mmap_vma_setup(bo, vma);
626         return 0;
627 out_unref:
628         ttm_bo_put(bo);
629         return ret;
630 }
631 EXPORT_SYMBOL(ttm_bo_mmap);
632
633 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
634 {
635         ttm_bo_get(bo);
636         ttm_bo_mmap_vma_setup(bo, vma);
637         return 0;
638 }
639 EXPORT_SYMBOL(ttm_bo_mmap_obj);