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_vma_manager.h>
35 #include <linux/io.h>
36 #include <linux/highmem.h>
37 #include <linux/wait.h>
38 #include <linux/slab.h>
39 #include <linux/vmalloc.h>
40 #include <linux/module.h>
41 #include <linux/dma-resv.h>
42
43 struct ttm_transfer_obj {
44 struct ttm_buffer_object base;
45 struct ttm_buffer_object *bo;
46 };
47
ttm_bo_free_old_node(struct ttm_buffer_object * bo)48 void ttm_bo_free_old_node(struct ttm_buffer_object *bo)
49 {
50 ttm_resource_free(bo, &bo->mem);
51 }
52
ttm_bo_move_ttm(struct ttm_buffer_object * bo,struct ttm_operation_ctx * ctx,struct ttm_resource * new_mem)53 int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
54 struct ttm_operation_ctx *ctx,
55 struct ttm_resource *new_mem)
56 {
57 struct ttm_tt *ttm = bo->ttm;
58 struct ttm_resource *old_mem = &bo->mem;
59 int ret;
60
61 if (old_mem->mem_type != TTM_PL_SYSTEM) {
62 ret = ttm_bo_wait(bo, ctx->interruptible, ctx->no_wait_gpu);
63
64 if (unlikely(ret != 0)) {
65 if (ret != -ERESTARTSYS)
66 pr_err("Failed to expire sync object before unbinding TTM\n");
67 return ret;
68 }
69
70 ttm_bo_tt_unbind(bo);
71 ttm_bo_free_old_node(bo);
72 old_mem->mem_type = TTM_PL_SYSTEM;
73 }
74
75 ret = ttm_tt_set_placement_caching(ttm, new_mem->placement);
76 if (unlikely(ret != 0))
77 return ret;
78
79 if (new_mem->mem_type != TTM_PL_SYSTEM) {
80
81 ret = ttm_tt_populate(bo->bdev, ttm, ctx);
82 if (unlikely(ret != 0))
83 return ret;
84
85 ret = ttm_bo_tt_bind(bo, new_mem);
86 if (unlikely(ret != 0))
87 return ret;
88 }
89
90 ttm_bo_assign_mem(bo, new_mem);
91 return 0;
92 }
93 EXPORT_SYMBOL(ttm_bo_move_ttm);
94
ttm_mem_io_reserve(struct ttm_bo_device * bdev,struct ttm_resource * mem)95 int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
96 struct ttm_resource *mem)
97 {
98 if (mem->bus.offset || mem->bus.addr)
99 return 0;
100
101 mem->bus.is_iomem = false;
102 if (!bdev->driver->io_mem_reserve)
103 return 0;
104
105 return bdev->driver->io_mem_reserve(bdev, mem);
106 }
107
ttm_mem_io_free(struct ttm_bo_device * bdev,struct ttm_resource * mem)108 void ttm_mem_io_free(struct ttm_bo_device *bdev,
109 struct ttm_resource *mem)
110 {
111 if (!mem->bus.offset && !mem->bus.addr)
112 return;
113
114 if (bdev->driver->io_mem_free)
115 bdev->driver->io_mem_free(bdev, mem);
116
117 mem->bus.offset = 0;
118 mem->bus.addr = NULL;
119 }
120
ttm_resource_ioremap(struct ttm_bo_device * bdev,struct ttm_resource * mem,void ** virtual)121 static int ttm_resource_ioremap(struct ttm_bo_device *bdev,
122 struct ttm_resource *mem,
123 void **virtual)
124 {
125 int ret;
126 void *addr;
127
128 *virtual = NULL;
129 ret = ttm_mem_io_reserve(bdev, mem);
130 if (ret || !mem->bus.is_iomem)
131 return ret;
132
133 if (mem->bus.addr) {
134 addr = mem->bus.addr;
135 } else {
136 size_t bus_size = (size_t)mem->num_pages << PAGE_SHIFT;
137
138 if (mem->placement & TTM_PL_FLAG_WC)
139 addr = ioremap_wc(mem->bus.offset, bus_size);
140 else
141 addr = ioremap(mem->bus.offset, bus_size);
142 if (!addr) {
143 ttm_mem_io_free(bdev, mem);
144 return -ENOMEM;
145 }
146 }
147 *virtual = addr;
148 return 0;
149 }
150
ttm_resource_iounmap(struct ttm_bo_device * bdev,struct ttm_resource * mem,void * virtual)151 static void ttm_resource_iounmap(struct ttm_bo_device *bdev,
152 struct ttm_resource *mem,
153 void *virtual)
154 {
155 if (virtual && mem->bus.addr == NULL)
156 iounmap(virtual);
157 ttm_mem_io_free(bdev, mem);
158 }
159
ttm_copy_io_page(void * dst,void * src,unsigned long page)160 static int ttm_copy_io_page(void *dst, void *src, unsigned long page)
161 {
162 uint32_t *dstP =
163 (uint32_t *) ((unsigned long)dst + (page << PAGE_SHIFT));
164 uint32_t *srcP =
165 (uint32_t *) ((unsigned long)src + (page << PAGE_SHIFT));
166
167 int i;
168 for (i = 0; i < PAGE_SIZE / sizeof(uint32_t); ++i)
169 iowrite32(ioread32(srcP++), dstP++);
170 return 0;
171 }
172
ttm_copy_io_ttm_page(struct ttm_tt * ttm,void * src,unsigned long page,pgprot_t prot)173 static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
174 unsigned long page,
175 pgprot_t prot)
176 {
177 struct page *d = ttm->pages[page];
178 void *dst;
179
180 if (!d)
181 return -ENOMEM;
182
183 src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
184 dst = kmap_atomic_prot(d, prot);
185 if (!dst)
186 return -ENOMEM;
187
188 memcpy_fromio(dst, src, PAGE_SIZE);
189
190 kunmap_atomic(dst);
191
192 return 0;
193 }
194
ttm_copy_ttm_io_page(struct ttm_tt * ttm,void * dst,unsigned long page,pgprot_t prot)195 static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
196 unsigned long page,
197 pgprot_t prot)
198 {
199 struct page *s = ttm->pages[page];
200 void *src;
201
202 if (!s)
203 return -ENOMEM;
204
205 dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
206 src = kmap_atomic_prot(s, prot);
207 if (!src)
208 return -ENOMEM;
209
210 memcpy_toio(dst, src, PAGE_SIZE);
211
212 kunmap_atomic(src);
213
214 return 0;
215 }
216
ttm_bo_move_memcpy(struct ttm_buffer_object * bo,struct ttm_operation_ctx * ctx,struct ttm_resource * new_mem)217 int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
218 struct ttm_operation_ctx *ctx,
219 struct ttm_resource *new_mem)
220 {
221 struct ttm_bo_device *bdev = bo->bdev;
222 struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
223 struct ttm_tt *ttm = bo->ttm;
224 struct ttm_resource *old_mem = &bo->mem;
225 struct ttm_resource old_copy = *old_mem;
226 void *old_iomap;
227 void *new_iomap;
228 int ret;
229 unsigned long i;
230 unsigned long page;
231 unsigned long add = 0;
232 int dir;
233
234 ret = ttm_bo_wait(bo, ctx->interruptible, ctx->no_wait_gpu);
235 if (ret)
236 return ret;
237
238 ret = ttm_resource_ioremap(bdev, old_mem, &old_iomap);
239 if (ret)
240 return ret;
241 ret = ttm_resource_ioremap(bdev, new_mem, &new_iomap);
242 if (ret)
243 goto out;
244
245 /*
246 * Single TTM move. NOP.
247 */
248 if (old_iomap == NULL && new_iomap == NULL)
249 goto out2;
250
251 /*
252 * Don't move nonexistent data. Clear destination instead.
253 */
254 if (old_iomap == NULL &&
255 (ttm == NULL || (!ttm_tt_is_populated(ttm) &&
256 !(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)))) {
257 memset_io(new_iomap, 0, new_mem->num_pages*PAGE_SIZE);
258 goto out2;
259 }
260
261 /*
262 * TTM might be null for moves within the same region.
263 */
264 if (ttm) {
265 ret = ttm_tt_populate(bdev, ttm, ctx);
266 if (ret)
267 goto out1;
268 }
269
270 add = 0;
271 dir = 1;
272
273 if ((old_mem->mem_type == new_mem->mem_type) &&
274 (new_mem->start < old_mem->start + old_mem->size)) {
275 dir = -1;
276 add = new_mem->num_pages - 1;
277 }
278
279 for (i = 0; i < new_mem->num_pages; ++i) {
280 page = i * dir + add;
281 if (old_iomap == NULL) {
282 pgprot_t prot = ttm_io_prot(old_mem->placement,
283 PAGE_KERNEL);
284 ret = ttm_copy_ttm_io_page(ttm, new_iomap, page,
285 prot);
286 } else if (new_iomap == NULL) {
287 pgprot_t prot = ttm_io_prot(new_mem->placement,
288 PAGE_KERNEL);
289 ret = ttm_copy_io_ttm_page(ttm, old_iomap, page,
290 prot);
291 } else {
292 ret = ttm_copy_io_page(new_iomap, old_iomap, page);
293 }
294 if (ret)
295 goto out1;
296 }
297 mb();
298 out2:
299 old_copy = *old_mem;
300
301 ttm_bo_assign_mem(bo, new_mem);
302
303 if (!man->use_tt)
304 ttm_bo_tt_destroy(bo);
305
306 out1:
307 ttm_resource_iounmap(bdev, old_mem, new_iomap);
308 out:
309 ttm_resource_iounmap(bdev, &old_copy, old_iomap);
310
311 /*
312 * On error, keep the mm node!
313 */
314 if (!ret)
315 ttm_resource_free(bo, &old_copy);
316 return ret;
317 }
318 EXPORT_SYMBOL(ttm_bo_move_memcpy);
319
ttm_transfered_destroy(struct ttm_buffer_object * bo)320 static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
321 {
322 struct ttm_transfer_obj *fbo;
323
324 fbo = container_of(bo, struct ttm_transfer_obj, base);
325 ttm_bo_put(fbo->bo);
326 kfree(fbo);
327 }
328
329 /**
330 * ttm_buffer_object_transfer
331 *
332 * @bo: A pointer to a struct ttm_buffer_object.
333 * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
334 * holding the data of @bo with the old placement.
335 *
336 * This is a utility function that may be called after an accelerated move
337 * has been scheduled. A new buffer object is created as a placeholder for
338 * the old data while it's being copied. When that buffer object is idle,
339 * it can be destroyed, releasing the space of the old placement.
340 * Returns:
341 * !0: Failure.
342 */
343
ttm_buffer_object_transfer(struct ttm_buffer_object * bo,struct ttm_buffer_object ** new_obj)344 static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
345 struct ttm_buffer_object **new_obj)
346 {
347 struct ttm_transfer_obj *fbo;
348 int ret;
349
350 fbo = kmalloc(sizeof(*fbo), GFP_KERNEL);
351 if (!fbo)
352 return -ENOMEM;
353
354 fbo->base = *bo;
355
356 ttm_bo_get(bo);
357 fbo->bo = bo;
358
359 /**
360 * Fix up members that we shouldn't copy directly:
361 * TODO: Explicit member copy would probably be better here.
362 */
363
364 atomic_inc(&ttm_bo_glob.bo_count);
365 INIT_LIST_HEAD(&fbo->base.ddestroy);
366 INIT_LIST_HEAD(&fbo->base.lru);
367 INIT_LIST_HEAD(&fbo->base.swap);
368 fbo->base.moving = NULL;
369 drm_vma_node_reset(&fbo->base.base.vma_node);
370
371 kref_init(&fbo->base.kref);
372 fbo->base.destroy = &ttm_transfered_destroy;
373 fbo->base.acc_size = 0;
374 fbo->base.pin_count = 1;
375 if (bo->type != ttm_bo_type_sg)
376 fbo->base.base.resv = &fbo->base.base._resv;
377
378 dma_resv_init(&fbo->base.base._resv);
379 fbo->base.base.dev = NULL;
380 ret = dma_resv_trylock(&fbo->base.base._resv);
381 WARN_ON(!ret);
382
383 *new_obj = &fbo->base;
384 return 0;
385 }
386
ttm_io_prot(uint32_t caching_flags,pgprot_t tmp)387 pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
388 {
389 /* Cached mappings need no adjustment */
390 if (caching_flags & TTM_PL_FLAG_CACHED)
391 return tmp;
392
393 #if defined(__i386__) || defined(__x86_64__)
394 if (caching_flags & TTM_PL_FLAG_WC)
395 tmp = pgprot_writecombine(tmp);
396 else if (boot_cpu_data.x86 > 3)
397 tmp = pgprot_noncached(tmp);
398 #endif
399 #if defined(__ia64__) || defined(__arm__) || defined(__aarch64__) || \
400 defined(__powerpc__) || defined(__mips__)
401 if (caching_flags & TTM_PL_FLAG_WC)
402 tmp = pgprot_writecombine(tmp);
403 else
404 tmp = pgprot_noncached(tmp);
405 #endif
406 #if defined(__sparc__)
407 tmp = pgprot_noncached(tmp);
408 #endif
409 return tmp;
410 }
411 EXPORT_SYMBOL(ttm_io_prot);
412
ttm_bo_ioremap(struct ttm_buffer_object * bo,unsigned long offset,unsigned long size,struct ttm_bo_kmap_obj * map)413 static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
414 unsigned long offset,
415 unsigned long size,
416 struct ttm_bo_kmap_obj *map)
417 {
418 struct ttm_resource *mem = &bo->mem;
419
420 if (bo->mem.bus.addr) {
421 map->bo_kmap_type = ttm_bo_map_premapped;
422 map->virtual = (void *)(((u8 *)bo->mem.bus.addr) + offset);
423 } else {
424 map->bo_kmap_type = ttm_bo_map_iomap;
425 if (mem->placement & TTM_PL_FLAG_WC)
426 map->virtual = ioremap_wc(bo->mem.bus.offset + offset,
427 size);
428 else
429 map->virtual = ioremap(bo->mem.bus.offset + offset,
430 size);
431 }
432 return (!map->virtual) ? -ENOMEM : 0;
433 }
434
ttm_bo_kmap_ttm(struct ttm_buffer_object * bo,unsigned long start_page,unsigned long num_pages,struct ttm_bo_kmap_obj * map)435 static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
436 unsigned long start_page,
437 unsigned long num_pages,
438 struct ttm_bo_kmap_obj *map)
439 {
440 struct ttm_resource *mem = &bo->mem;
441 struct ttm_operation_ctx ctx = {
442 .interruptible = false,
443 .no_wait_gpu = false
444 };
445 struct ttm_tt *ttm = bo->ttm;
446 pgprot_t prot;
447 int ret;
448
449 BUG_ON(!ttm);
450
451 ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
452 if (ret)
453 return ret;
454
455 if (num_pages == 1 && (mem->placement & TTM_PL_FLAG_CACHED)) {
456 /*
457 * We're mapping a single page, and the desired
458 * page protection is consistent with the bo.
459 */
460
461 map->bo_kmap_type = ttm_bo_map_kmap;
462 map->page = ttm->pages[start_page];
463 map->virtual = kmap(map->page);
464 } else {
465 /*
466 * We need to use vmap to get the desired page protection
467 * or to make the buffer object look contiguous.
468 */
469 prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
470 map->bo_kmap_type = ttm_bo_map_vmap;
471 map->virtual = vmap(ttm->pages + start_page, num_pages,
472 0, prot);
473 }
474 return (!map->virtual) ? -ENOMEM : 0;
475 }
476
ttm_bo_kmap(struct ttm_buffer_object * bo,unsigned long start_page,unsigned long num_pages,struct ttm_bo_kmap_obj * map)477 int ttm_bo_kmap(struct ttm_buffer_object *bo,
478 unsigned long start_page, unsigned long num_pages,
479 struct ttm_bo_kmap_obj *map)
480 {
481 unsigned long offset, size;
482 int ret;
483
484 map->virtual = NULL;
485 map->bo = bo;
486 if (num_pages > bo->num_pages)
487 return -EINVAL;
488 if (start_page > bo->num_pages)
489 return -EINVAL;
490
491 ret = ttm_mem_io_reserve(bo->bdev, &bo->mem);
492 if (ret)
493 return ret;
494 if (!bo->mem.bus.is_iomem) {
495 return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
496 } else {
497 offset = start_page << PAGE_SHIFT;
498 size = num_pages << PAGE_SHIFT;
499 return ttm_bo_ioremap(bo, offset, size, map);
500 }
501 }
502 EXPORT_SYMBOL(ttm_bo_kmap);
503
ttm_bo_kunmap(struct ttm_bo_kmap_obj * map)504 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
505 {
506 if (!map->virtual)
507 return;
508 switch (map->bo_kmap_type) {
509 case ttm_bo_map_iomap:
510 iounmap(map->virtual);
511 break;
512 case ttm_bo_map_vmap:
513 vunmap(map->virtual);
514 break;
515 case ttm_bo_map_kmap:
516 kunmap(map->page);
517 break;
518 case ttm_bo_map_premapped:
519 break;
520 default:
521 BUG();
522 }
523 ttm_mem_io_free(map->bo->bdev, &map->bo->mem);
524 map->virtual = NULL;
525 map->page = NULL;
526 }
527 EXPORT_SYMBOL(ttm_bo_kunmap);
528
ttm_bo_wait_free_node(struct ttm_buffer_object * bo,bool dst_use_tt)529 static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
530 bool dst_use_tt)
531 {
532 int ret;
533 ret = ttm_bo_wait(bo, false, false);
534 if (ret)
535 return ret;
536
537 if (!dst_use_tt)
538 ttm_bo_tt_destroy(bo);
539 ttm_bo_free_old_node(bo);
540 return 0;
541 }
542
ttm_bo_move_to_ghost(struct ttm_buffer_object * bo,struct dma_fence * fence,bool dst_use_tt)543 static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
544 struct dma_fence *fence,
545 bool dst_use_tt)
546 {
547 struct ttm_buffer_object *ghost_obj;
548 int ret;
549
550 /**
551 * This should help pipeline ordinary buffer moves.
552 *
553 * Hang old buffer memory on a new buffer object,
554 * and leave it to be released when the GPU
555 * operation has completed.
556 */
557
558 dma_fence_put(bo->moving);
559 bo->moving = dma_fence_get(fence);
560
561 ret = ttm_buffer_object_transfer(bo, &ghost_obj);
562 if (ret)
563 return ret;
564
565 dma_resv_add_excl_fence(&ghost_obj->base._resv, fence);
566
567 /**
568 * If we're not moving to fixed memory, the TTM object
569 * needs to stay alive. Otherwhise hang it on the ghost
570 * bo to be unbound and destroyed.
571 */
572
573 if (dst_use_tt)
574 ghost_obj->ttm = NULL;
575 else
576 bo->ttm = NULL;
577
578 dma_resv_unlock(&ghost_obj->base._resv);
579 ttm_bo_put(ghost_obj);
580 return 0;
581 }
582
ttm_bo_move_pipeline_evict(struct ttm_buffer_object * bo,struct dma_fence * fence)583 static void ttm_bo_move_pipeline_evict(struct ttm_buffer_object *bo,
584 struct dma_fence *fence)
585 {
586 struct ttm_bo_device *bdev = bo->bdev;
587 struct ttm_resource_manager *from = ttm_manager_type(bdev, bo->mem.mem_type);
588
589 /**
590 * BO doesn't have a TTM we need to bind/unbind. Just remember
591 * this eviction and free up the allocation
592 */
593 spin_lock(&from->move_lock);
594 if (!from->move || dma_fence_is_later(fence, from->move)) {
595 dma_fence_put(from->move);
596 from->move = dma_fence_get(fence);
597 }
598 spin_unlock(&from->move_lock);
599
600 ttm_bo_free_old_node(bo);
601
602 dma_fence_put(bo->moving);
603 bo->moving = dma_fence_get(fence);
604 }
605
ttm_bo_move_accel_cleanup(struct ttm_buffer_object * bo,struct dma_fence * fence,bool evict,bool pipeline,struct ttm_resource * new_mem)606 int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
607 struct dma_fence *fence,
608 bool evict,
609 bool pipeline,
610 struct ttm_resource *new_mem)
611 {
612 struct ttm_bo_device *bdev = bo->bdev;
613 struct ttm_resource_manager *from = ttm_manager_type(bdev, bo->mem.mem_type);
614 struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
615 int ret = 0;
616
617 dma_resv_add_excl_fence(bo->base.resv, fence);
618 if (!evict)
619 ret = ttm_bo_move_to_ghost(bo, fence, man->use_tt);
620 else if (!from->use_tt && pipeline)
621 ttm_bo_move_pipeline_evict(bo, fence);
622 else
623 ret = ttm_bo_wait_free_node(bo, man->use_tt);
624
625 if (ret)
626 return ret;
627
628 ttm_bo_assign_mem(bo, new_mem);
629
630 return 0;
631 }
632 EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
633
ttm_bo_pipeline_gutting(struct ttm_buffer_object * bo)634 int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
635 {
636 struct ttm_buffer_object *ghost;
637 int ret;
638
639 ret = ttm_buffer_object_transfer(bo, &ghost);
640 if (ret)
641 return ret;
642
643 ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv);
644 /* Last resort, wait for the BO to be idle when we are OOM */
645 if (ret)
646 ttm_bo_wait(bo, false, false);
647
648 memset(&bo->mem, 0, sizeof(bo->mem));
649 bo->mem.mem_type = TTM_PL_SYSTEM;
650 bo->ttm = NULL;
651
652 dma_resv_unlock(&ghost->base._resv);
653 ttm_bo_put(ghost);
654
655 return 0;
656 }
657