xref: /freebsd/sys/dev/drm2/ttm/ttm_bo_util.c (revision 595e514d0df2bac5b813d35f83e32875dbf16a83)
1 /**************************************************************************
2  *
3  * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
26  **************************************************************************/
27 /*
28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <dev/drm2/drmP.h>
35 #include <dev/drm2/ttm/ttm_bo_driver.h>
36 #include <dev/drm2/ttm/ttm_placement.h>
37 #include <sys/sf_buf.h>
38 
39 void ttm_bo_free_old_node(struct ttm_buffer_object *bo)
40 {
41 	ttm_bo_mem_put(bo, &bo->mem);
42 }
43 
44 int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
45 		    bool evict,
46 		    bool no_wait_gpu, struct ttm_mem_reg *new_mem)
47 {
48 	struct ttm_tt *ttm = bo->ttm;
49 	struct ttm_mem_reg *old_mem = &bo->mem;
50 	int ret;
51 
52 	if (old_mem->mem_type != TTM_PL_SYSTEM) {
53 		ttm_tt_unbind(ttm);
54 		ttm_bo_free_old_node(bo);
55 		ttm_flag_masked(&old_mem->placement, TTM_PL_FLAG_SYSTEM,
56 				TTM_PL_MASK_MEM);
57 		old_mem->mem_type = TTM_PL_SYSTEM;
58 	}
59 
60 	ret = ttm_tt_set_placement_caching(ttm, new_mem->placement);
61 	if (unlikely(ret != 0))
62 		return ret;
63 
64 	if (new_mem->mem_type != TTM_PL_SYSTEM) {
65 		ret = ttm_tt_bind(ttm, new_mem);
66 		if (unlikely(ret != 0))
67 			return ret;
68 	}
69 
70 	*old_mem = *new_mem;
71 	new_mem->mm_node = NULL;
72 
73 	return 0;
74 }
75 
76 int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible)
77 {
78 	if (likely(man->io_reserve_fastpath))
79 		return 0;
80 
81 	if (interruptible) {
82 		if (sx_xlock_sig(&man->io_reserve_mutex))
83 			return (-EINTR);
84 		else
85 			return (0);
86 	}
87 
88 	sx_xlock(&man->io_reserve_mutex);
89 	return 0;
90 }
91 
92 void ttm_mem_io_unlock(struct ttm_mem_type_manager *man)
93 {
94 	if (likely(man->io_reserve_fastpath))
95 		return;
96 
97 	sx_xunlock(&man->io_reserve_mutex);
98 }
99 
100 static int ttm_mem_io_evict(struct ttm_mem_type_manager *man)
101 {
102 	struct ttm_buffer_object *bo;
103 
104 	if (!man->use_io_reserve_lru || list_empty(&man->io_reserve_lru))
105 		return -EAGAIN;
106 
107 	bo = list_first_entry(&man->io_reserve_lru,
108 			      struct ttm_buffer_object,
109 			      io_reserve_lru);
110 	list_del_init(&bo->io_reserve_lru);
111 	ttm_bo_unmap_virtual_locked(bo);
112 
113 	return 0;
114 }
115 
116 static int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
117 			      struct ttm_mem_reg *mem)
118 {
119 	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
120 	int ret = 0;
121 
122 	if (!bdev->driver->io_mem_reserve)
123 		return 0;
124 	if (likely(man->io_reserve_fastpath))
125 		return bdev->driver->io_mem_reserve(bdev, mem);
126 
127 	if (bdev->driver->io_mem_reserve &&
128 	    mem->bus.io_reserved_count++ == 0) {
129 retry:
130 		ret = bdev->driver->io_mem_reserve(bdev, mem);
131 		if (ret == -EAGAIN) {
132 			ret = ttm_mem_io_evict(man);
133 			if (ret == 0)
134 				goto retry;
135 		}
136 	}
137 	return ret;
138 }
139 
140 static void ttm_mem_io_free(struct ttm_bo_device *bdev,
141 			    struct ttm_mem_reg *mem)
142 {
143 	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
144 
145 	if (likely(man->io_reserve_fastpath))
146 		return;
147 
148 	if (bdev->driver->io_mem_reserve &&
149 	    --mem->bus.io_reserved_count == 0 &&
150 	    bdev->driver->io_mem_free)
151 		bdev->driver->io_mem_free(bdev, mem);
152 
153 }
154 
155 int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo)
156 {
157 	struct ttm_mem_reg *mem = &bo->mem;
158 	int ret;
159 
160 	if (!mem->bus.io_reserved_vm) {
161 		struct ttm_mem_type_manager *man =
162 			&bo->bdev->man[mem->mem_type];
163 
164 		ret = ttm_mem_io_reserve(bo->bdev, mem);
165 		if (unlikely(ret != 0))
166 			return ret;
167 		mem->bus.io_reserved_vm = true;
168 		if (man->use_io_reserve_lru)
169 			list_add_tail(&bo->io_reserve_lru,
170 				      &man->io_reserve_lru);
171 	}
172 	return 0;
173 }
174 
175 void ttm_mem_io_free_vm(struct ttm_buffer_object *bo)
176 {
177 	struct ttm_mem_reg *mem = &bo->mem;
178 
179 	if (mem->bus.io_reserved_vm) {
180 		mem->bus.io_reserved_vm = false;
181 		list_del_init(&bo->io_reserve_lru);
182 		ttm_mem_io_free(bo->bdev, mem);
183 	}
184 }
185 
186 static
187 int ttm_mem_reg_ioremap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
188 			void **virtual)
189 {
190 	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
191 	int ret;
192 	void *addr;
193 
194 	*virtual = NULL;
195 	(void) ttm_mem_io_lock(man, false);
196 	ret = ttm_mem_io_reserve(bdev, mem);
197 	ttm_mem_io_unlock(man);
198 	if (ret || !mem->bus.is_iomem)
199 		return ret;
200 
201 	if (mem->bus.addr) {
202 		addr = mem->bus.addr;
203 	} else {
204 		addr = pmap_mapdev_attr(mem->bus.base + mem->bus.offset,
205 		    mem->bus.size, (mem->placement & TTM_PL_FLAG_WC) ?
206 		    VM_MEMATTR_WRITE_COMBINING : VM_MEMATTR_UNCACHEABLE);
207 		if (!addr) {
208 			(void) ttm_mem_io_lock(man, false);
209 			ttm_mem_io_free(bdev, mem);
210 			ttm_mem_io_unlock(man);
211 			return -ENOMEM;
212 		}
213 	}
214 	*virtual = addr;
215 	return 0;
216 }
217 
218 static
219 void ttm_mem_reg_iounmap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,
220 			 void *virtual)
221 {
222 	struct ttm_mem_type_manager *man;
223 
224 	man = &bdev->man[mem->mem_type];
225 
226 	if (virtual && mem->bus.addr == NULL)
227 		pmap_unmapdev((vm_offset_t)virtual, mem->bus.size);
228 	(void) ttm_mem_io_lock(man, false);
229 	ttm_mem_io_free(bdev, mem);
230 	ttm_mem_io_unlock(man);
231 }
232 
233 static int ttm_copy_io_page(void *dst, void *src, unsigned long page)
234 {
235 	uint32_t *dstP =
236 	    (uint32_t *) ((unsigned long)dst + (page << PAGE_SHIFT));
237 	uint32_t *srcP =
238 	    (uint32_t *) ((unsigned long)src + (page << PAGE_SHIFT));
239 
240 	int i;
241 	for (i = 0; i < PAGE_SIZE / sizeof(uint32_t); ++i)
242 		/* iowrite32(ioread32(srcP++), dstP++); */
243 		*dstP++ = *srcP++;
244 	return 0;
245 }
246 
247 static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
248 				unsigned long page,
249 				vm_memattr_t prot)
250 {
251 	vm_page_t d = ttm->pages[page];
252 	void *dst;
253 
254 	if (!d)
255 		return -ENOMEM;
256 
257 	src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
258 
259 	/* XXXKIB can't sleep ? */
260 	dst = pmap_mapdev_attr(VM_PAGE_TO_PHYS(d), PAGE_SIZE, prot);
261 	if (!dst)
262 		return -ENOMEM;
263 
264 	memcpy(dst, src, PAGE_SIZE);
265 
266 	pmap_unmapdev((vm_offset_t)dst, PAGE_SIZE);
267 
268 	return 0;
269 }
270 
271 static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
272 				unsigned long page,
273 				vm_memattr_t prot)
274 {
275 	vm_page_t s = ttm->pages[page];
276 	void *src;
277 
278 	if (!s)
279 		return -ENOMEM;
280 
281 	dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
282 	src = pmap_mapdev_attr(VM_PAGE_TO_PHYS(s), PAGE_SIZE, prot);
283 	if (!src)
284 		return -ENOMEM;
285 
286 	memcpy(dst, src, PAGE_SIZE);
287 
288 	pmap_unmapdev((vm_offset_t)src, PAGE_SIZE);
289 
290 	return 0;
291 }
292 
293 int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
294 		       bool evict, bool no_wait_gpu,
295 		       struct ttm_mem_reg *new_mem)
296 {
297 	struct ttm_bo_device *bdev = bo->bdev;
298 	struct ttm_mem_type_manager *man = &bdev->man[new_mem->mem_type];
299 	struct ttm_tt *ttm = bo->ttm;
300 	struct ttm_mem_reg *old_mem = &bo->mem;
301 	struct ttm_mem_reg old_copy = *old_mem;
302 	void *old_iomap;
303 	void *new_iomap;
304 	int ret;
305 	unsigned long i;
306 	unsigned long page;
307 	unsigned long add = 0;
308 	int dir;
309 
310 	ret = ttm_mem_reg_ioremap(bdev, old_mem, &old_iomap);
311 	if (ret)
312 		return ret;
313 	ret = ttm_mem_reg_ioremap(bdev, new_mem, &new_iomap);
314 	if (ret)
315 		goto out;
316 
317 	if (old_iomap == NULL && new_iomap == NULL)
318 		goto out2;
319 	if (old_iomap == NULL && ttm == NULL)
320 		goto out2;
321 
322 	if (ttm->state == tt_unpopulated) {
323 		ret = ttm->bdev->driver->ttm_tt_populate(ttm);
324 		if (ret)
325 			goto out1;
326 	}
327 
328 	add = 0;
329 	dir = 1;
330 
331 	if ((old_mem->mem_type == new_mem->mem_type) &&
332 	    (new_mem->start < old_mem->start + old_mem->size)) {
333 		dir = -1;
334 		add = new_mem->num_pages - 1;
335 	}
336 
337 	for (i = 0; i < new_mem->num_pages; ++i) {
338 		page = i * dir + add;
339 		if (old_iomap == NULL) {
340 			vm_memattr_t prot = ttm_io_prot(old_mem->placement);
341 			ret = ttm_copy_ttm_io_page(ttm, new_iomap, page,
342 						   prot);
343 		} else if (new_iomap == NULL) {
344 			vm_memattr_t prot = ttm_io_prot(new_mem->placement);
345 			ret = ttm_copy_io_ttm_page(ttm, old_iomap, page,
346 						   prot);
347 		} else
348 			ret = ttm_copy_io_page(new_iomap, old_iomap, page);
349 		if (ret)
350 			goto out1;
351 	}
352 	mb();
353 out2:
354 	old_copy = *old_mem;
355 	*old_mem = *new_mem;
356 	new_mem->mm_node = NULL;
357 
358 	if ((man->flags & TTM_MEMTYPE_FLAG_FIXED) && (ttm != NULL)) {
359 		ttm_tt_unbind(ttm);
360 		ttm_tt_destroy(ttm);
361 		bo->ttm = NULL;
362 	}
363 
364 out1:
365 	ttm_mem_reg_iounmap(bdev, old_mem, new_iomap);
366 out:
367 	ttm_mem_reg_iounmap(bdev, &old_copy, old_iomap);
368 	ttm_bo_mem_put(bo, &old_copy);
369 	return ret;
370 }
371 
372 MALLOC_DEFINE(M_TTM_TRANSF_OBJ, "ttm_transf_obj", "TTM Transfer Objects");
373 
374 static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
375 {
376 	free(bo, M_TTM_TRANSF_OBJ);
377 }
378 
379 /**
380  * ttm_buffer_object_transfer
381  *
382  * @bo: A pointer to a struct ttm_buffer_object.
383  * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
384  * holding the data of @bo with the old placement.
385  *
386  * This is a utility function that may be called after an accelerated move
387  * has been scheduled. A new buffer object is created as a placeholder for
388  * the old data while it's being copied. When that buffer object is idle,
389  * it can be destroyed, releasing the space of the old placement.
390  * Returns:
391  * !0: Failure.
392  */
393 
394 static int
395 ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
396     void *sync_obj, struct ttm_buffer_object **new_obj)
397 {
398 	struct ttm_buffer_object *fbo;
399 
400 	fbo = malloc(sizeof(*fbo), M_TTM_TRANSF_OBJ, M_ZERO | M_WAITOK);
401 	*fbo = *bo;
402 
403 	/**
404 	 * Fix up members that we shouldn't copy directly:
405 	 * TODO: Explicit member copy would probably be better here.
406 	 */
407 
408 	INIT_LIST_HEAD(&fbo->ddestroy);
409 	INIT_LIST_HEAD(&fbo->lru);
410 	INIT_LIST_HEAD(&fbo->swap);
411 	INIT_LIST_HEAD(&fbo->io_reserve_lru);
412 	fbo->vm_node = NULL;
413 	atomic_set(&fbo->cpu_writers, 0);
414 
415 	fbo->sync_obj = sync_obj;
416 	refcount_init(&fbo->list_kref, 1);
417 	refcount_init(&fbo->kref, 1);
418 	fbo->destroy = &ttm_transfered_destroy;
419 	fbo->acc_size = 0;
420 
421 	*new_obj = fbo;
422 	return 0;
423 }
424 
425 vm_memattr_t
426 ttm_io_prot(uint32_t caching_flags)
427 {
428 #if defined(__i386__) || defined(__amd64__)
429 	if (caching_flags & TTM_PL_FLAG_WC)
430 		return (VM_MEMATTR_WRITE_COMBINING);
431 	else
432 		/*
433 		 * We do not support i386, look at the linux source
434 		 * for the reason of the comment.
435 		 */
436 		return (VM_MEMATTR_UNCACHEABLE);
437 #else
438 #error Port me
439 #endif
440 }
441 
442 static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
443 			  unsigned long offset,
444 			  unsigned long size,
445 			  struct ttm_bo_kmap_obj *map)
446 {
447 	struct ttm_mem_reg *mem = &bo->mem;
448 
449 	if (bo->mem.bus.addr) {
450 		map->bo_kmap_type = ttm_bo_map_premapped;
451 		map->virtual = (void *)(((u8 *)bo->mem.bus.addr) + offset);
452 	} else {
453 		map->bo_kmap_type = ttm_bo_map_iomap;
454 		map->virtual = pmap_mapdev_attr(bo->mem.bus.base +
455 		    bo->mem.bus.offset + offset, size,
456 		    (mem->placement & TTM_PL_FLAG_WC) ?
457 		    VM_MEMATTR_WRITE_COMBINING : VM_MEMATTR_UNCACHEABLE);
458 		map->size = size;
459 	}
460 	return (!map->virtual) ? -ENOMEM : 0;
461 }
462 
463 static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
464 			   unsigned long start_page,
465 			   unsigned long num_pages,
466 			   struct ttm_bo_kmap_obj *map)
467 {
468 	struct ttm_mem_reg *mem = &bo->mem;
469 	vm_memattr_t prot;
470 	struct ttm_tt *ttm = bo->ttm;
471 	int i, ret;
472 
473 	MPASS(ttm != NULL);
474 
475 	if (ttm->state == tt_unpopulated) {
476 		ret = ttm->bdev->driver->ttm_tt_populate(ttm);
477 		if (ret)
478 			return ret;
479 	}
480 
481 	if (num_pages == 1 && (mem->placement & TTM_PL_FLAG_CACHED)) {
482 		/*
483 		 * We're mapping a single page, and the desired
484 		 * page protection is consistent with the bo.
485 		 */
486 
487 		map->bo_kmap_type = ttm_bo_map_kmap;
488 		map->page = ttm->pages[start_page];
489 		map->sf = sf_buf_alloc(map->page, 0);
490 		map->virtual = (void *)sf_buf_kva(map->sf);
491 	} else {
492 		/*
493 		 * We need to use vmap to get the desired page protection
494 		 * or to make the buffer object look contiguous.
495 		 */
496 		prot = (mem->placement & TTM_PL_FLAG_CACHED) ?
497 			VM_MEMATTR_WRITE_COMBINING :
498 			ttm_io_prot(mem->placement);
499 		map->bo_kmap_type = ttm_bo_map_vmap;
500 		map->num_pages = num_pages;
501 		map->virtual = (void *)kmem_alloc_nofault(kernel_map,
502 		    num_pages * PAGE_SIZE);
503 		if (map->virtual != NULL) {
504 			for (i = 0; i < num_pages; i++) {
505 				/* XXXKIB hack */
506 				pmap_page_set_memattr(ttm->pages[start_page +
507 				    i], prot);
508 			}
509 			pmap_qenter((vm_offset_t)map->virtual,
510 			    &ttm->pages[start_page], num_pages);
511 		}
512 	}
513 	return (!map->virtual) ? -ENOMEM : 0;
514 }
515 
516 int ttm_bo_kmap(struct ttm_buffer_object *bo,
517 		unsigned long start_page, unsigned long num_pages,
518 		struct ttm_bo_kmap_obj *map)
519 {
520 	struct ttm_mem_type_manager *man =
521 		&bo->bdev->man[bo->mem.mem_type];
522 	unsigned long offset, size;
523 	int ret;
524 
525 	MPASS(list_empty(&bo->swap));
526 	map->virtual = NULL;
527 	map->bo = bo;
528 	if (num_pages > bo->num_pages)
529 		return -EINVAL;
530 	if (start_page > bo->num_pages)
531 		return -EINVAL;
532 #if 0
533 	if (num_pages > 1 && !DRM_SUSER(DRM_CURPROC))
534 		return -EPERM;
535 #endif
536 	(void) ttm_mem_io_lock(man, false);
537 	ret = ttm_mem_io_reserve(bo->bdev, &bo->mem);
538 	ttm_mem_io_unlock(man);
539 	if (ret)
540 		return ret;
541 	if (!bo->mem.bus.is_iomem) {
542 		return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
543 	} else {
544 		offset = start_page << PAGE_SHIFT;
545 		size = num_pages << PAGE_SHIFT;
546 		return ttm_bo_ioremap(bo, offset, size, map);
547 	}
548 }
549 
550 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
551 {
552 	struct ttm_buffer_object *bo = map->bo;
553 	struct ttm_mem_type_manager *man =
554 		&bo->bdev->man[bo->mem.mem_type];
555 
556 	if (!map->virtual)
557 		return;
558 	switch (map->bo_kmap_type) {
559 	case ttm_bo_map_iomap:
560 		pmap_unmapdev((vm_offset_t)map->virtual, map->size);
561 		break;
562 	case ttm_bo_map_vmap:
563 		pmap_qremove((vm_offset_t)(map->virtual), map->num_pages);
564 		kmem_free(kernel_map, (vm_offset_t)map->virtual,
565 		    map->num_pages * PAGE_SIZE);
566 		break;
567 	case ttm_bo_map_kmap:
568 		sf_buf_free(map->sf);
569 		break;
570 	case ttm_bo_map_premapped:
571 		break;
572 	default:
573 		MPASS(0);
574 	}
575 	(void) ttm_mem_io_lock(man, false);
576 	ttm_mem_io_free(map->bo->bdev, &map->bo->mem);
577 	ttm_mem_io_unlock(man);
578 	map->virtual = NULL;
579 	map->page = NULL;
580 	map->sf = NULL;
581 }
582 
583 int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
584 			      void *sync_obj,
585 			      bool evict,
586 			      bool no_wait_gpu,
587 			      struct ttm_mem_reg *new_mem)
588 {
589 	struct ttm_bo_device *bdev = bo->bdev;
590 	struct ttm_bo_driver *driver = bdev->driver;
591 	struct ttm_mem_type_manager *man = &bdev->man[new_mem->mem_type];
592 	struct ttm_mem_reg *old_mem = &bo->mem;
593 	int ret;
594 	struct ttm_buffer_object *ghost_obj;
595 	void *tmp_obj = NULL;
596 	void *sync_obj_ref;
597 
598 	mtx_lock(&bdev->fence_lock);
599 	if (bo->sync_obj) {
600 		tmp_obj = bo->sync_obj;
601 		bo->sync_obj = NULL;
602 	}
603 	bo->sync_obj = driver->sync_obj_ref(sync_obj);
604 	if (evict) {
605 		ret = ttm_bo_wait(bo, false, false, false);
606 		mtx_unlock(&bdev->fence_lock);
607 		if (tmp_obj)
608 			driver->sync_obj_unref(&tmp_obj);
609 		if (ret)
610 			return ret;
611 
612 		if ((man->flags & TTM_MEMTYPE_FLAG_FIXED) &&
613 		    (bo->ttm != NULL)) {
614 			ttm_tt_unbind(bo->ttm);
615 			ttm_tt_destroy(bo->ttm);
616 			bo->ttm = NULL;
617 		}
618 		ttm_bo_free_old_node(bo);
619 	} else {
620 		/**
621 		 * This should help pipeline ordinary buffer moves.
622 		 *
623 		 * Hang old buffer memory on a new buffer object,
624 		 * and leave it to be released when the GPU
625 		 * operation has completed.
626 		 */
627 
628 		set_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags);
629 
630 		sync_obj_ref = bo->bdev->driver->sync_obj_ref(bo->sync_obj);
631 		mtx_unlock(&bdev->fence_lock);
632 		/* ttm_buffer_object_transfer accesses bo->sync_obj */
633 		ret = ttm_buffer_object_transfer(bo, sync_obj_ref, &ghost_obj);
634 		if (tmp_obj)
635 			driver->sync_obj_unref(&tmp_obj);
636 
637 		if (ret)
638 			return ret;
639 
640 		/**
641 		 * If we're not moving to fixed memory, the TTM object
642 		 * needs to stay alive. Otherwhise hang it on the ghost
643 		 * bo to be unbound and destroyed.
644 		 */
645 
646 		if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED))
647 			ghost_obj->ttm = NULL;
648 		else
649 			bo->ttm = NULL;
650 
651 		ttm_bo_unreserve(ghost_obj);
652 		ttm_bo_unref(&ghost_obj);
653 	}
654 
655 	*old_mem = *new_mem;
656 	new_mem->mm_node = NULL;
657 
658 	return 0;
659 }
660