1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
2 /**************************************************************************
3 *
4 * Copyright (c) 2007-2009 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 #include <drm/ttm/ttm_bo_driver.h>
33 #include <drm/ttm/ttm_placement.h>
34 #include <drm/drm_cache.h>
35 #include <drm/drm_vma_manager.h>
36 #include <linux/dma-buf-map.h>
37 #include <linux/io.h>
38 #include <linux/highmem.h>
39 #include <linux/wait.h>
40 #include <linux/slab.h>
41 #include <linux/vmalloc.h>
42 #include <linux/module.h>
43 #include <linux/dma-resv.h>
44
45 struct ttm_transfer_obj {
46 struct ttm_buffer_object base;
47 struct ttm_buffer_object *bo;
48 };
49
ttm_mem_io_reserve(struct ttm_device * bdev,struct ttm_resource * mem)50 int ttm_mem_io_reserve(struct ttm_device *bdev,
51 struct ttm_resource *mem)
52 {
53 if (mem->bus.offset || mem->bus.addr)
54 return 0;
55
56 mem->bus.is_iomem = false;
57 if (!bdev->funcs->io_mem_reserve)
58 return 0;
59
60 return bdev->funcs->io_mem_reserve(bdev, mem);
61 }
62
ttm_mem_io_free(struct ttm_device * bdev,struct ttm_resource * mem)63 void ttm_mem_io_free(struct ttm_device *bdev,
64 struct ttm_resource *mem)
65 {
66 if (!mem)
67 return;
68
69 if (!mem->bus.offset && !mem->bus.addr)
70 return;
71
72 if (bdev->funcs->io_mem_free)
73 bdev->funcs->io_mem_free(bdev, mem);
74
75 mem->bus.offset = 0;
76 mem->bus.addr = NULL;
77 }
78
79 /**
80 * ttm_move_memcpy - Helper to perform a memcpy ttm move operation.
81 * @clear: Whether to clear rather than copy.
82 * @num_pages: Number of pages of the operation.
83 * @dst_iter: A struct ttm_kmap_iter representing the destination resource.
84 * @src_iter: A struct ttm_kmap_iter representing the source resource.
85 *
86 * This function is intended to be able to move out async under a
87 * dma-fence if desired.
88 */
ttm_move_memcpy(bool clear,u32 num_pages,struct ttm_kmap_iter * dst_iter,struct ttm_kmap_iter * src_iter)89 void ttm_move_memcpy(bool clear,
90 u32 num_pages,
91 struct ttm_kmap_iter *dst_iter,
92 struct ttm_kmap_iter *src_iter)
93 {
94 const struct ttm_kmap_iter_ops *dst_ops = dst_iter->ops;
95 const struct ttm_kmap_iter_ops *src_ops = src_iter->ops;
96 struct dma_buf_map src_map, dst_map;
97 pgoff_t i;
98
99 /* Single TTM move. NOP */
100 if (dst_ops->maps_tt && src_ops->maps_tt)
101 return;
102
103 /* Don't move nonexistent data. Clear destination instead. */
104 if (clear) {
105 for (i = 0; i < num_pages; ++i) {
106 dst_ops->map_local(dst_iter, &dst_map, i);
107 if (dst_map.is_iomem)
108 memset_io(dst_map.vaddr_iomem, 0, PAGE_SIZE);
109 else
110 memset(dst_map.vaddr, 0, PAGE_SIZE);
111 if (dst_ops->unmap_local)
112 dst_ops->unmap_local(dst_iter, &dst_map);
113 }
114 return;
115 }
116
117 for (i = 0; i < num_pages; ++i) {
118 dst_ops->map_local(dst_iter, &dst_map, i);
119 src_ops->map_local(src_iter, &src_map, i);
120
121 drm_memcpy_from_wc(&dst_map, &src_map, PAGE_SIZE);
122
123 if (src_ops->unmap_local)
124 src_ops->unmap_local(src_iter, &src_map);
125 if (dst_ops->unmap_local)
126 dst_ops->unmap_local(dst_iter, &dst_map);
127 }
128 }
129 EXPORT_SYMBOL(ttm_move_memcpy);
130
ttm_bo_move_memcpy(struct ttm_buffer_object * bo,struct ttm_operation_ctx * ctx,struct ttm_resource * dst_mem)131 int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
132 struct ttm_operation_ctx *ctx,
133 struct ttm_resource *dst_mem)
134 {
135 struct ttm_device *bdev = bo->bdev;
136 struct ttm_resource_manager *dst_man =
137 ttm_manager_type(bo->bdev, dst_mem->mem_type);
138 struct ttm_tt *ttm = bo->ttm;
139 struct ttm_resource *src_mem = bo->resource;
140 struct ttm_resource_manager *src_man =
141 ttm_manager_type(bdev, src_mem->mem_type);
142 union {
143 struct ttm_kmap_iter_tt tt;
144 struct ttm_kmap_iter_linear_io io;
145 } _dst_iter, _src_iter;
146 struct ttm_kmap_iter *dst_iter, *src_iter;
147 bool clear;
148 int ret = 0;
149
150 if (ttm && ((ttm->page_flags & TTM_TT_FLAG_SWAPPED) ||
151 dst_man->use_tt)) {
152 ret = ttm_tt_populate(bdev, ttm, ctx);
153 if (ret)
154 return ret;
155 }
156
157 dst_iter = ttm_kmap_iter_linear_io_init(&_dst_iter.io, bdev, dst_mem);
158 if (PTR_ERR(dst_iter) == -EINVAL && dst_man->use_tt)
159 dst_iter = ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm);
160 if (IS_ERR(dst_iter))
161 return PTR_ERR(dst_iter);
162
163 src_iter = ttm_kmap_iter_linear_io_init(&_src_iter.io, bdev, src_mem);
164 if (PTR_ERR(src_iter) == -EINVAL && src_man->use_tt)
165 src_iter = ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm);
166 if (IS_ERR(src_iter)) {
167 ret = PTR_ERR(src_iter);
168 goto out_src_iter;
169 }
170
171 clear = src_iter->ops->maps_tt && (!ttm || !ttm_tt_is_populated(ttm));
172 if (!(clear && ttm && !(ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC)))
173 ttm_move_memcpy(clear, dst_mem->num_pages, dst_iter, src_iter);
174
175 if (!src_iter->ops->maps_tt)
176 ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, src_mem);
177 ttm_bo_move_sync_cleanup(bo, dst_mem);
178
179 out_src_iter:
180 if (!dst_iter->ops->maps_tt)
181 ttm_kmap_iter_linear_io_fini(&_dst_iter.io, bdev, dst_mem);
182
183 return ret;
184 }
185 EXPORT_SYMBOL(ttm_bo_move_memcpy);
186
ttm_transfered_destroy(struct ttm_buffer_object * bo)187 static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
188 {
189 struct ttm_transfer_obj *fbo;
190
191 fbo = container_of(bo, struct ttm_transfer_obj, base);
192 dma_resv_fini(&fbo->base.base._resv);
193 ttm_bo_put(fbo->bo);
194 kfree(fbo);
195 }
196
197 /**
198 * ttm_buffer_object_transfer
199 *
200 * @bo: A pointer to a struct ttm_buffer_object.
201 * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
202 * holding the data of @bo with the old placement.
203 *
204 * This is a utility function that may be called after an accelerated move
205 * has been scheduled. A new buffer object is created as a placeholder for
206 * the old data while it's being copied. When that buffer object is idle,
207 * it can be destroyed, releasing the space of the old placement.
208 * Returns:
209 * !0: Failure.
210 */
211
ttm_buffer_object_transfer(struct ttm_buffer_object * bo,struct ttm_buffer_object ** new_obj)212 static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
213 struct ttm_buffer_object **new_obj)
214 {
215 struct ttm_transfer_obj *fbo;
216 int ret;
217
218 fbo = kmalloc(sizeof(*fbo), GFP_KERNEL);
219 if (!fbo)
220 return -ENOMEM;
221
222 fbo->base = *bo;
223
224 ttm_bo_get(bo);
225 fbo->bo = bo;
226
227 /**
228 * Fix up members that we shouldn't copy directly:
229 * TODO: Explicit member copy would probably be better here.
230 */
231
232 atomic_inc(&ttm_glob.bo_count);
233 INIT_LIST_HEAD(&fbo->base.ddestroy);
234 INIT_LIST_HEAD(&fbo->base.lru);
235 fbo->base.moving = NULL;
236 drm_vma_node_reset(&fbo->base.base.vma_node);
237
238 kref_init(&fbo->base.kref);
239 fbo->base.destroy = &ttm_transfered_destroy;
240 fbo->base.pin_count = 0;
241 if (bo->type != ttm_bo_type_sg)
242 fbo->base.base.resv = &fbo->base.base._resv;
243
244 dma_resv_init(&fbo->base.base._resv);
245 fbo->base.base.dev = NULL;
246 ret = dma_resv_trylock(&fbo->base.base._resv);
247 WARN_ON(!ret);
248
249 ttm_bo_move_to_lru_tail_unlocked(&fbo->base);
250
251 *new_obj = &fbo->base;
252 return 0;
253 }
254
ttm_io_prot(struct ttm_buffer_object * bo,struct ttm_resource * res,pgprot_t tmp)255 pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct ttm_resource *res,
256 pgprot_t tmp)
257 {
258 struct ttm_resource_manager *man;
259 enum ttm_caching caching;
260
261 man = ttm_manager_type(bo->bdev, res->mem_type);
262 caching = man->use_tt ? bo->ttm->caching : res->bus.caching;
263
264 return ttm_prot_from_caching(caching, tmp);
265 }
266 EXPORT_SYMBOL(ttm_io_prot);
267
ttm_bo_ioremap(struct ttm_buffer_object * bo,unsigned long offset,unsigned long size,struct ttm_bo_kmap_obj * map)268 static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
269 unsigned long offset,
270 unsigned long size,
271 struct ttm_bo_kmap_obj *map)
272 {
273 struct ttm_resource *mem = bo->resource;
274
275 if (bo->resource->bus.addr) {
276 map->bo_kmap_type = ttm_bo_map_premapped;
277 map->virtual = ((u8 *)bo->resource->bus.addr) + offset;
278 } else {
279 resource_size_t res = bo->resource->bus.offset + offset;
280
281 map->bo_kmap_type = ttm_bo_map_iomap;
282 if (mem->bus.caching == ttm_write_combined)
283 map->virtual = ioremap_wc(res, size);
284 #ifdef CONFIG_X86
285 else if (mem->bus.caching == ttm_cached)
286 map->virtual = ioremap_cache(res, size);
287 #endif
288 else
289 map->virtual = ioremap(res, size);
290 }
291 return (!map->virtual) ? -ENOMEM : 0;
292 }
293
ttm_bo_kmap_ttm(struct ttm_buffer_object * bo,unsigned long start_page,unsigned long num_pages,struct ttm_bo_kmap_obj * map)294 static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
295 unsigned long start_page,
296 unsigned long num_pages,
297 struct ttm_bo_kmap_obj *map)
298 {
299 struct ttm_resource *mem = bo->resource;
300 struct ttm_operation_ctx ctx = {
301 .interruptible = false,
302 .no_wait_gpu = false
303 };
304 struct ttm_tt *ttm = bo->ttm;
305 pgprot_t prot;
306 int ret;
307
308 BUG_ON(!ttm);
309
310 ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
311 if (ret)
312 return ret;
313
314 if (num_pages == 1 && ttm->caching == ttm_cached) {
315 /*
316 * We're mapping a single page, and the desired
317 * page protection is consistent with the bo.
318 */
319
320 map->bo_kmap_type = ttm_bo_map_kmap;
321 map->page = ttm->pages[start_page];
322 map->virtual = kmap(map->page);
323 } else {
324 /*
325 * We need to use vmap to get the desired page protection
326 * or to make the buffer object look contiguous.
327 */
328 prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
329 map->bo_kmap_type = ttm_bo_map_vmap;
330 map->virtual = vmap(ttm->pages + start_page, num_pages,
331 0, prot);
332 }
333 return (!map->virtual) ? -ENOMEM : 0;
334 }
335
ttm_bo_kmap(struct ttm_buffer_object * bo,unsigned long start_page,unsigned long num_pages,struct ttm_bo_kmap_obj * map)336 int ttm_bo_kmap(struct ttm_buffer_object *bo,
337 unsigned long start_page, unsigned long num_pages,
338 struct ttm_bo_kmap_obj *map)
339 {
340 unsigned long offset, size;
341 int ret;
342
343 map->virtual = NULL;
344 map->bo = bo;
345 if (num_pages > bo->resource->num_pages)
346 return -EINVAL;
347 if ((start_page + num_pages) > bo->resource->num_pages)
348 return -EINVAL;
349
350 ret = ttm_mem_io_reserve(bo->bdev, bo->resource);
351 if (ret)
352 return ret;
353 if (!bo->resource->bus.is_iomem) {
354 return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
355 } else {
356 offset = start_page << PAGE_SHIFT;
357 size = num_pages << PAGE_SHIFT;
358 return ttm_bo_ioremap(bo, offset, size, map);
359 }
360 }
361 EXPORT_SYMBOL(ttm_bo_kmap);
362
ttm_bo_kunmap(struct ttm_bo_kmap_obj * map)363 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
364 {
365 if (!map->virtual)
366 return;
367 switch (map->bo_kmap_type) {
368 case ttm_bo_map_iomap:
369 iounmap(map->virtual);
370 break;
371 case ttm_bo_map_vmap:
372 vunmap(map->virtual);
373 break;
374 case ttm_bo_map_kmap:
375 kunmap(map->page);
376 break;
377 case ttm_bo_map_premapped:
378 break;
379 default:
380 BUG();
381 }
382 ttm_mem_io_free(map->bo->bdev, map->bo->resource);
383 map->virtual = NULL;
384 map->page = NULL;
385 }
386 EXPORT_SYMBOL(ttm_bo_kunmap);
387
ttm_bo_vmap(struct ttm_buffer_object * bo,struct dma_buf_map * map)388 int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
389 {
390 struct ttm_resource *mem = bo->resource;
391 int ret;
392
393 ret = ttm_mem_io_reserve(bo->bdev, mem);
394 if (ret)
395 return ret;
396
397 if (mem->bus.is_iomem) {
398 void __iomem *vaddr_iomem;
399
400 if (mem->bus.addr)
401 vaddr_iomem = (void __iomem *)mem->bus.addr;
402 else if (mem->bus.caching == ttm_write_combined)
403 vaddr_iomem = ioremap_wc(mem->bus.offset,
404 bo->base.size);
405 #ifdef CONFIG_X86
406 else if (mem->bus.caching == ttm_cached)
407 vaddr_iomem = ioremap_cache(mem->bus.offset,
408 bo->base.size);
409 #endif
410 else
411 vaddr_iomem = ioremap(mem->bus.offset, bo->base.size);
412
413 if (!vaddr_iomem)
414 return -ENOMEM;
415
416 dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
417
418 } else {
419 struct ttm_operation_ctx ctx = {
420 .interruptible = false,
421 .no_wait_gpu = false
422 };
423 struct ttm_tt *ttm = bo->ttm;
424 pgprot_t prot;
425 void *vaddr;
426
427 ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
428 if (ret)
429 return ret;
430
431 /*
432 * We need to use vmap to get the desired page protection
433 * or to make the buffer object look contiguous.
434 */
435 prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
436 vaddr = vmap(ttm->pages, ttm->num_pages, 0, prot);
437 if (!vaddr)
438 return -ENOMEM;
439
440 dma_buf_map_set_vaddr(map, vaddr);
441 }
442
443 return 0;
444 }
445 EXPORT_SYMBOL(ttm_bo_vmap);
446
ttm_bo_vunmap(struct ttm_buffer_object * bo,struct dma_buf_map * map)447 void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
448 {
449 struct ttm_resource *mem = bo->resource;
450
451 if (dma_buf_map_is_null(map))
452 return;
453
454 if (!map->is_iomem)
455 vunmap(map->vaddr);
456 else if (!mem->bus.addr)
457 iounmap(map->vaddr_iomem);
458 dma_buf_map_clear(map);
459
460 ttm_mem_io_free(bo->bdev, bo->resource);
461 }
462 EXPORT_SYMBOL(ttm_bo_vunmap);
463
ttm_bo_wait_free_node(struct ttm_buffer_object * bo,bool dst_use_tt)464 static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
465 bool dst_use_tt)
466 {
467 int ret;
468 ret = ttm_bo_wait(bo, false, false);
469 if (ret)
470 return ret;
471
472 if (!dst_use_tt)
473 ttm_bo_tt_destroy(bo);
474 ttm_resource_free(bo, &bo->resource);
475 return 0;
476 }
477
ttm_bo_move_to_ghost(struct ttm_buffer_object * bo,struct dma_fence * fence,bool dst_use_tt)478 static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
479 struct dma_fence *fence,
480 bool dst_use_tt)
481 {
482 struct ttm_buffer_object *ghost_obj;
483 int ret;
484
485 /**
486 * This should help pipeline ordinary buffer moves.
487 *
488 * Hang old buffer memory on a new buffer object,
489 * and leave it to be released when the GPU
490 * operation has completed.
491 */
492
493 dma_fence_put(bo->moving);
494 bo->moving = dma_fence_get(fence);
495
496 ret = ttm_buffer_object_transfer(bo, &ghost_obj);
497 if (ret)
498 return ret;
499
500 dma_resv_add_excl_fence(&ghost_obj->base._resv, fence);
501
502 /**
503 * If we're not moving to fixed memory, the TTM object
504 * needs to stay alive. Otherwhise hang it on the ghost
505 * bo to be unbound and destroyed.
506 */
507
508 if (dst_use_tt)
509 ghost_obj->ttm = NULL;
510 else
511 bo->ttm = NULL;
512 bo->resource = NULL;
513
514 dma_resv_unlock(&ghost_obj->base._resv);
515 ttm_bo_put(ghost_obj);
516 return 0;
517 }
518
ttm_bo_move_pipeline_evict(struct ttm_buffer_object * bo,struct dma_fence * fence)519 static void ttm_bo_move_pipeline_evict(struct ttm_buffer_object *bo,
520 struct dma_fence *fence)
521 {
522 struct ttm_device *bdev = bo->bdev;
523 struct ttm_resource_manager *from;
524
525 from = ttm_manager_type(bdev, bo->resource->mem_type);
526
527 /**
528 * BO doesn't have a TTM we need to bind/unbind. Just remember
529 * this eviction and free up the allocation
530 */
531 spin_lock(&from->move_lock);
532 if (!from->move || dma_fence_is_later(fence, from->move)) {
533 dma_fence_put(from->move);
534 from->move = dma_fence_get(fence);
535 }
536 spin_unlock(&from->move_lock);
537
538 ttm_resource_free(bo, &bo->resource);
539
540 dma_fence_put(bo->moving);
541 bo->moving = dma_fence_get(fence);
542 }
543
ttm_bo_move_accel_cleanup(struct ttm_buffer_object * bo,struct dma_fence * fence,bool evict,bool pipeline,struct ttm_resource * new_mem)544 int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
545 struct dma_fence *fence,
546 bool evict,
547 bool pipeline,
548 struct ttm_resource *new_mem)
549 {
550 struct ttm_device *bdev = bo->bdev;
551 struct ttm_resource_manager *from = ttm_manager_type(bdev, bo->resource->mem_type);
552 struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
553 int ret = 0;
554
555 dma_resv_add_excl_fence(bo->base.resv, fence);
556 if (!evict)
557 ret = ttm_bo_move_to_ghost(bo, fence, man->use_tt);
558 else if (!from->use_tt && pipeline)
559 ttm_bo_move_pipeline_evict(bo, fence);
560 else
561 ret = ttm_bo_wait_free_node(bo, man->use_tt);
562
563 if (ret)
564 return ret;
565
566 ttm_bo_assign_mem(bo, new_mem);
567
568 return 0;
569 }
570 EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
571
572 /**
573 * ttm_bo_pipeline_gutting - purge the contents of a bo
574 * @bo: The buffer object
575 *
576 * Purge the contents of a bo, async if the bo is not idle.
577 * After a successful call, the bo is left unpopulated in
578 * system placement. The function may wait uninterruptible
579 * for idle on OOM.
580 *
581 * Return: 0 if successful, negative error code on failure.
582 */
ttm_bo_pipeline_gutting(struct ttm_buffer_object * bo)583 int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
584 {
585 static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
586 struct ttm_buffer_object *ghost;
587 struct ttm_resource *sys_res;
588 struct ttm_tt *ttm;
589 int ret;
590
591 ret = ttm_resource_alloc(bo, &sys_mem, &sys_res);
592 if (ret)
593 return ret;
594
595 /* If already idle, no need for ghost object dance. */
596 ret = ttm_bo_wait(bo, false, true);
597 if (ret != -EBUSY) {
598 if (!bo->ttm) {
599 /* See comment below about clearing. */
600 ret = ttm_tt_create(bo, true);
601 if (ret)
602 goto error_free_sys_mem;
603 } else {
604 ttm_tt_unpopulate(bo->bdev, bo->ttm);
605 if (bo->type == ttm_bo_type_device)
606 ttm_tt_mark_for_clear(bo->ttm);
607 }
608 ttm_resource_free(bo, &bo->resource);
609 ttm_bo_assign_mem(bo, sys_res);
610 return 0;
611 }
612
613 /*
614 * We need an unpopulated ttm_tt after giving our current one,
615 * if any, to the ghost object. And we can't afford to fail
616 * creating one *after* the operation. If the bo subsequently gets
617 * resurrected, make sure it's cleared (if ttm_bo_type_device)
618 * to avoid leaking sensitive information to user-space.
619 */
620
621 ttm = bo->ttm;
622 bo->ttm = NULL;
623 ret = ttm_tt_create(bo, true);
624 swap(bo->ttm, ttm);
625 if (ret)
626 goto error_free_sys_mem;
627
628 ret = ttm_buffer_object_transfer(bo, &ghost);
629 if (ret)
630 goto error_destroy_tt;
631
632 ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv);
633 /* Last resort, wait for the BO to be idle when we are OOM */
634 if (ret)
635 ttm_bo_wait(bo, false, false);
636
637 dma_resv_unlock(&ghost->base._resv);
638 ttm_bo_put(ghost);
639 bo->ttm = ttm;
640 bo->resource = NULL;
641 ttm_bo_assign_mem(bo, sys_res);
642 return 0;
643
644 error_destroy_tt:
645 ttm_tt_destroy(bo->bdev, ttm);
646
647 error_free_sys_mem:
648 ttm_resource_free(bo, &sys_res);
649 return ret;
650 }
651