1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /**************************************************************************
3  *
4  * Copyright © 2018 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 #include <linux/slab.h>
29 #include "vmwgfx_validation.h"
30 #include "vmwgfx_drv.h"
31 
32 /**
33  * struct vmw_validation_bo_node - Buffer object validation metadata.
34  * @base: Metadata used for TTM reservation- and validation.
35  * @hash: A hash entry used for the duplicate detection hash table.
36  * @coherent_count: If switching backup buffers, number of new coherent
37  * resources that will have this buffer as a backup buffer.
38  * @as_mob: Validate as mob.
39  * @cpu_blit: Validate for cpu blit access.
40  *
41  * Bit fields are used since these structures are allocated and freed in
42  * large numbers and space conservation is desired.
43  */
44 struct vmw_validation_bo_node {
45 	struct ttm_validate_buffer base;
46 	struct drm_hash_item hash;
47 	unsigned int coherent_count;
48 	u32 as_mob : 1;
49 	u32 cpu_blit : 1;
50 };
51 /**
52  * struct vmw_validation_res_node - Resource validation metadata.
53  * @head: List head for the resource validation list.
54  * @hash: A hash entry used for the duplicate detection hash table.
55  * @res: Reference counted resource pointer.
56  * @new_backup: Non ref-counted pointer to new backup buffer to be assigned
57  * to a resource.
58  * @new_backup_offset: Offset into the new backup mob for resources that can
59  * share MOBs.
60  * @no_buffer_needed: Kernel does not need to allocate a MOB during validation,
61  * the command stream provides a mob bind operation.
62  * @switching_backup: The validation process is switching backup MOB.
63  * @first_usage: True iff the resource has been seen only once in the current
64  * validation batch.
65  * @reserved: Whether the resource is currently reserved by this process.
66  * @dirty_set: Change dirty status of the resource.
67  * @dirty: Dirty information VMW_RES_DIRTY_XX.
68  * @private: Optionally additional memory for caller-private data.
69  *
70  * Bit fields are used since these structures are allocated and freed in
71  * large numbers and space conservation is desired.
72  */
73 struct vmw_validation_res_node {
74 	struct list_head head;
75 	struct drm_hash_item hash;
76 	struct vmw_resource *res;
77 	struct vmw_buffer_object *new_backup;
78 	unsigned long new_backup_offset;
79 	u32 no_buffer_needed : 1;
80 	u32 switching_backup : 1;
81 	u32 first_usage : 1;
82 	u32 reserved : 1;
83 	u32 dirty : 1;
84 	u32 dirty_set : 1;
85 	unsigned long private[];
86 };
87 
88 /**
89  * vmw_validation_mem_alloc - Allocate kernel memory from the validation
90  * context based allocator
91  * @ctx: The validation context
92  * @size: The number of bytes to allocated.
93  *
94  * The memory allocated may not exceed PAGE_SIZE, and the returned
95  * address is aligned to sizeof(long). All memory allocated this way is
96  * reclaimed after validation when calling any of the exported functions:
97  * vmw_validation_unref_lists()
98  * vmw_validation_revert()
99  * vmw_validation_done()
100  *
101  * Return: Pointer to the allocated memory on success. NULL on failure.
102  */
103 void *vmw_validation_mem_alloc(struct vmw_validation_context *ctx,
104 			       unsigned int size)
105 {
106 	void *addr;
107 
108 	size = vmw_validation_align(size);
109 	if (size > PAGE_SIZE)
110 		return NULL;
111 
112 	if (ctx->mem_size_left < size) {
113 		struct page *page;
114 
115 		if (ctx->vm && ctx->vm_size_left < PAGE_SIZE) {
116 			int ret = ctx->vm->reserve_mem(ctx->vm, ctx->vm->gran);
117 
118 			if (ret)
119 				return NULL;
120 
121 			ctx->vm_size_left += ctx->vm->gran;
122 			ctx->total_mem += ctx->vm->gran;
123 		}
124 
125 		page = alloc_page(GFP_KERNEL | __GFP_ZERO);
126 		if (!page)
127 			return NULL;
128 
129 		if (ctx->vm)
130 			ctx->vm_size_left -= PAGE_SIZE;
131 
132 		list_add_tail(&page->lru, &ctx->page_list);
133 		ctx->page_address = page_address(page);
134 		ctx->mem_size_left = PAGE_SIZE;
135 	}
136 
137 	addr = (void *) (ctx->page_address + (PAGE_SIZE - ctx->mem_size_left));
138 	ctx->mem_size_left -= size;
139 
140 	return addr;
141 }
142 
143 /**
144  * vmw_validation_mem_free - Free all memory allocated using
145  * vmw_validation_mem_alloc()
146  * @ctx: The validation context
147  *
148  * All memory previously allocated for this context using
149  * vmw_validation_mem_alloc() is freed.
150  */
151 static void vmw_validation_mem_free(struct vmw_validation_context *ctx)
152 {
153 	struct page *entry, *next;
154 
155 	list_for_each_entry_safe(entry, next, &ctx->page_list, lru) {
156 		list_del_init(&entry->lru);
157 		__free_page(entry);
158 	}
159 
160 	ctx->mem_size_left = 0;
161 	if (ctx->vm && ctx->total_mem) {
162 		ctx->vm->unreserve_mem(ctx->vm, ctx->total_mem);
163 		ctx->total_mem = 0;
164 		ctx->vm_size_left = 0;
165 	}
166 }
167 
168 /**
169  * vmw_validation_find_bo_dup - Find a duplicate buffer object entry in the
170  * validation context's lists.
171  * @ctx: The validation context to search.
172  * @vbo: The buffer object to search for.
173  *
174  * Return: Pointer to the struct vmw_validation_bo_node referencing the
175  * duplicate, or NULL if none found.
176  */
177 static struct vmw_validation_bo_node *
178 vmw_validation_find_bo_dup(struct vmw_validation_context *ctx,
179 			   struct vmw_buffer_object *vbo)
180 {
181 	struct  vmw_validation_bo_node *bo_node = NULL;
182 
183 	if (!ctx->merge_dups)
184 		return NULL;
185 
186 	if (ctx->ht) {
187 		struct drm_hash_item *hash;
188 
189 		if (!drm_ht_find_item(ctx->ht, (unsigned long) vbo, &hash))
190 			bo_node = container_of(hash, typeof(*bo_node), hash);
191 	} else {
192 		struct  vmw_validation_bo_node *entry;
193 
194 		list_for_each_entry(entry, &ctx->bo_list, base.head) {
195 			if (entry->base.bo == &vbo->base) {
196 				bo_node = entry;
197 				break;
198 			}
199 		}
200 	}
201 
202 	return bo_node;
203 }
204 
205 /**
206  * vmw_validation_find_res_dup - Find a duplicate resource entry in the
207  * validation context's lists.
208  * @ctx: The validation context to search.
209  * @res: Reference counted resource pointer.
210  *
211  * Return: Pointer to the struct vmw_validation_bo_node referencing the
212  * duplicate, or NULL if none found.
213  */
214 static struct vmw_validation_res_node *
215 vmw_validation_find_res_dup(struct vmw_validation_context *ctx,
216 			    struct vmw_resource *res)
217 {
218 	struct  vmw_validation_res_node *res_node = NULL;
219 
220 	if (!ctx->merge_dups)
221 		return NULL;
222 
223 	if (ctx->ht) {
224 		struct drm_hash_item *hash;
225 
226 		if (!drm_ht_find_item(ctx->ht, (unsigned long) res, &hash))
227 			res_node = container_of(hash, typeof(*res_node), hash);
228 	} else {
229 		struct  vmw_validation_res_node *entry;
230 
231 		list_for_each_entry(entry, &ctx->resource_ctx_list, head) {
232 			if (entry->res == res) {
233 				res_node = entry;
234 				goto out;
235 			}
236 		}
237 
238 		list_for_each_entry(entry, &ctx->resource_list, head) {
239 			if (entry->res == res) {
240 				res_node = entry;
241 				break;
242 			}
243 		}
244 
245 	}
246 out:
247 	return res_node;
248 }
249 
250 /**
251  * vmw_validation_add_bo - Add a buffer object to the validation context.
252  * @ctx: The validation context.
253  * @vbo: The buffer object.
254  * @as_mob: Validate as mob, otherwise suitable for GMR operations.
255  * @cpu_blit: Validate in a page-mappable location.
256  *
257  * Return: Zero on success, negative error code otherwise.
258  */
259 int vmw_validation_add_bo(struct vmw_validation_context *ctx,
260 			  struct vmw_buffer_object *vbo,
261 			  bool as_mob,
262 			  bool cpu_blit)
263 {
264 	struct vmw_validation_bo_node *bo_node;
265 
266 	bo_node = vmw_validation_find_bo_dup(ctx, vbo);
267 	if (bo_node) {
268 		if (bo_node->as_mob != as_mob ||
269 		    bo_node->cpu_blit != cpu_blit) {
270 			DRM_ERROR("Inconsistent buffer usage.\n");
271 			return -EINVAL;
272 		}
273 	} else {
274 		struct ttm_validate_buffer *val_buf;
275 		int ret;
276 
277 		bo_node = vmw_validation_mem_alloc(ctx, sizeof(*bo_node));
278 		if (!bo_node)
279 			return -ENOMEM;
280 
281 		if (ctx->ht) {
282 			bo_node->hash.key = (unsigned long) vbo;
283 			ret = drm_ht_insert_item(ctx->ht, &bo_node->hash);
284 			if (ret) {
285 				DRM_ERROR("Failed to initialize a buffer "
286 					  "validation entry.\n");
287 				return ret;
288 			}
289 		}
290 		val_buf = &bo_node->base;
291 		val_buf->bo = ttm_bo_get_unless_zero(&vbo->base);
292 		if (!val_buf->bo)
293 			return -ESRCH;
294 		val_buf->num_shared = 0;
295 		list_add_tail(&val_buf->head, &ctx->bo_list);
296 		bo_node->as_mob = as_mob;
297 		bo_node->cpu_blit = cpu_blit;
298 	}
299 
300 	return 0;
301 }
302 
303 /**
304  * vmw_validation_add_resource - Add a resource to the validation context.
305  * @ctx: The validation context.
306  * @res: The resource.
307  * @priv_size: Size of private, additional metadata.
308  * @dirty: Whether to change dirty status.
309  * @p_node: Output pointer of additional metadata address.
310  * @first_usage: Whether this was the first time this resource was seen.
311  *
312  * Return: Zero on success, negative error code otherwise.
313  */
314 int vmw_validation_add_resource(struct vmw_validation_context *ctx,
315 				struct vmw_resource *res,
316 				size_t priv_size,
317 				u32 dirty,
318 				void **p_node,
319 				bool *first_usage)
320 {
321 	struct vmw_validation_res_node *node;
322 	int ret;
323 
324 	node = vmw_validation_find_res_dup(ctx, res);
325 	if (node) {
326 		node->first_usage = 0;
327 		goto out_fill;
328 	}
329 
330 	node = vmw_validation_mem_alloc(ctx, sizeof(*node) + priv_size);
331 	if (!node) {
332 		VMW_DEBUG_USER("Failed to allocate a resource validation entry.\n");
333 		return -ENOMEM;
334 	}
335 
336 	if (ctx->ht) {
337 		node->hash.key = (unsigned long) res;
338 		ret = drm_ht_insert_item(ctx->ht, &node->hash);
339 		if (ret) {
340 			DRM_ERROR("Failed to initialize a resource validation "
341 				  "entry.\n");
342 			return ret;
343 		}
344 	}
345 	node->res = vmw_resource_reference_unless_doomed(res);
346 	if (!node->res)
347 		return -ESRCH;
348 
349 	node->first_usage = 1;
350 	if (!res->dev_priv->has_mob) {
351 		list_add_tail(&node->head, &ctx->resource_list);
352 	} else {
353 		switch (vmw_res_type(res)) {
354 		case vmw_res_context:
355 		case vmw_res_dx_context:
356 			list_add(&node->head, &ctx->resource_ctx_list);
357 			break;
358 		case vmw_res_cotable:
359 			list_add_tail(&node->head, &ctx->resource_ctx_list);
360 			break;
361 		default:
362 			list_add_tail(&node->head, &ctx->resource_list);
363 			break;
364 		}
365 	}
366 
367 out_fill:
368 	if (dirty) {
369 		node->dirty_set = 1;
370 		/* Overwriting previous information here is intentional! */
371 		node->dirty = (dirty & VMW_RES_DIRTY_SET) ? 1 : 0;
372 	}
373 	if (first_usage)
374 		*first_usage = node->first_usage;
375 	if (p_node)
376 		*p_node = &node->private;
377 
378 	return 0;
379 }
380 
381 /**
382  * vmw_validation_res_set_dirty - Register a resource dirty set or clear during
383  * validation.
384  * @ctx: The validation context.
385  * @val_private: The additional meta-data pointer returned when the
386  * resource was registered with the validation context. Used to identify
387  * the resource.
388  * @dirty: Dirty information VMW_RES_DIRTY_XX
389  */
390 void vmw_validation_res_set_dirty(struct vmw_validation_context *ctx,
391 				  void *val_private, u32 dirty)
392 {
393 	struct vmw_validation_res_node *val;
394 
395 	if (!dirty)
396 		return;
397 
398 	val = container_of(val_private, typeof(*val), private);
399 	val->dirty_set = 1;
400 	/* Overwriting previous information here is intentional! */
401 	val->dirty = (dirty & VMW_RES_DIRTY_SET) ? 1 : 0;
402 }
403 
404 /**
405  * vmw_validation_res_switch_backup - Register a backup MOB switch during
406  * validation.
407  * @ctx: The validation context.
408  * @val_private: The additional meta-data pointer returned when the
409  * resource was registered with the validation context. Used to identify
410  * the resource.
411  * @vbo: The new backup buffer object MOB. This buffer object needs to have
412  * already been registered with the validation context.
413  * @backup_offset: Offset into the new backup MOB.
414  */
415 void vmw_validation_res_switch_backup(struct vmw_validation_context *ctx,
416 				      void *val_private,
417 				      struct vmw_buffer_object *vbo,
418 				      unsigned long backup_offset)
419 {
420 	struct vmw_validation_res_node *val;
421 
422 	val = container_of(val_private, typeof(*val), private);
423 
424 	val->switching_backup = 1;
425 	if (val->first_usage)
426 		val->no_buffer_needed = 1;
427 
428 	val->new_backup = vbo;
429 	val->new_backup_offset = backup_offset;
430 }
431 
432 /**
433  * vmw_validation_res_reserve - Reserve all resources registered with this
434  * validation context.
435  * @ctx: The validation context.
436  * @intr: Use interruptible waits when possible.
437  *
438  * Return: Zero on success, -ERESTARTSYS if interrupted. Negative error
439  * code on failure.
440  */
441 int vmw_validation_res_reserve(struct vmw_validation_context *ctx,
442 			       bool intr)
443 {
444 	struct vmw_validation_res_node *val;
445 	int ret = 0;
446 
447 	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
448 
449 	list_for_each_entry(val, &ctx->resource_list, head) {
450 		struct vmw_resource *res = val->res;
451 
452 		ret = vmw_resource_reserve(res, intr, val->no_buffer_needed);
453 		if (ret)
454 			goto out_unreserve;
455 
456 		val->reserved = 1;
457 		if (res->backup) {
458 			struct vmw_buffer_object *vbo = res->backup;
459 
460 			ret = vmw_validation_add_bo
461 				(ctx, vbo, vmw_resource_needs_backup(res),
462 				 false);
463 			if (ret)
464 				goto out_unreserve;
465 		}
466 
467 		if (val->switching_backup && val->new_backup &&
468 		    res->coherent) {
469 			struct vmw_validation_bo_node *bo_node =
470 				vmw_validation_find_bo_dup(ctx,
471 							   val->new_backup);
472 
473 			if (WARN_ON(!bo_node)) {
474 				ret = -EINVAL;
475 				goto out_unreserve;
476 			}
477 			bo_node->coherent_count++;
478 		}
479 	}
480 
481 	return 0;
482 
483 out_unreserve:
484 	vmw_validation_res_unreserve(ctx, true);
485 	return ret;
486 }
487 
488 /**
489  * vmw_validation_res_unreserve - Unreserve all reserved resources
490  * registered with this validation context.
491  * @ctx: The validation context.
492  * @backoff: Whether this is a backoff- of a commit-type operation. This
493  * is used to determine whether to switch backup MOBs or not.
494  */
495 void vmw_validation_res_unreserve(struct vmw_validation_context *ctx,
496 				 bool backoff)
497 {
498 	struct vmw_validation_res_node *val;
499 
500 	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
501 	if (backoff)
502 		list_for_each_entry(val, &ctx->resource_list, head) {
503 			if (val->reserved)
504 				vmw_resource_unreserve(val->res,
505 						       false, false, false,
506 						       NULL, 0);
507 		}
508 	else
509 		list_for_each_entry(val, &ctx->resource_list, head) {
510 			if (val->reserved)
511 				vmw_resource_unreserve(val->res,
512 						       val->dirty_set,
513 						       val->dirty,
514 						       val->switching_backup,
515 						       val->new_backup,
516 						       val->new_backup_offset);
517 		}
518 }
519 
520 /**
521  * vmw_validation_bo_validate_single - Validate a single buffer object.
522  * @bo: The TTM buffer object base.
523  * @interruptible: Whether to perform waits interruptible if possible.
524  * @validate_as_mob: Whether to validate in MOB memory.
525  *
526  * Return: Zero on success, -ERESTARTSYS if interrupted. Negative error
527  * code on failure.
528  */
529 int vmw_validation_bo_validate_single(struct ttm_buffer_object *bo,
530 				      bool interruptible,
531 				      bool validate_as_mob)
532 {
533 	struct vmw_buffer_object *vbo =
534 		container_of(bo, struct vmw_buffer_object, base);
535 	struct ttm_operation_ctx ctx = {
536 		.interruptible = interruptible,
537 		.no_wait_gpu = false
538 	};
539 	int ret;
540 
541 	if (atomic_read(&vbo->cpu_writers))
542 		return -EBUSY;
543 
544 	if (vbo->base.pin_count > 0)
545 		return 0;
546 
547 	if (validate_as_mob)
548 		return ttm_bo_validate(bo, &vmw_mob_placement, &ctx);
549 
550 	/**
551 	 * Put BO in VRAM if there is space, otherwise as a GMR.
552 	 * If there is no space in VRAM and GMR ids are all used up,
553 	 * start evicting GMRs to make room. If the DMA buffer can't be
554 	 * used as a GMR, this will return -ENOMEM.
555 	 */
556 
557 	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, &ctx);
558 	if (ret == 0 || ret == -ERESTARTSYS)
559 		return ret;
560 
561 	/**
562 	 * If that failed, try VRAM again, this time evicting
563 	 * previous contents.
564 	 */
565 
566 	ret = ttm_bo_validate(bo, &vmw_vram_placement, &ctx);
567 	return ret;
568 }
569 
570 /**
571  * vmw_validation_bo_validate - Validate all buffer objects registered with
572  * the validation context.
573  * @ctx: The validation context.
574  * @intr: Whether to perform waits interruptible if possible.
575  *
576  * Return: Zero on success, -ERESTARTSYS if interrupted,
577  * negative error code on failure.
578  */
579 int vmw_validation_bo_validate(struct vmw_validation_context *ctx, bool intr)
580 {
581 	struct vmw_validation_bo_node *entry;
582 	int ret;
583 
584 	list_for_each_entry(entry, &ctx->bo_list, base.head) {
585 		struct vmw_buffer_object *vbo =
586 			container_of(entry->base.bo, typeof(*vbo), base);
587 
588 		if (entry->cpu_blit) {
589 			struct ttm_operation_ctx ctx = {
590 				.interruptible = intr,
591 				.no_wait_gpu = false
592 			};
593 
594 			ret = ttm_bo_validate(entry->base.bo,
595 					      &vmw_nonfixed_placement, &ctx);
596 		} else {
597 			ret = vmw_validation_bo_validate_single
598 			(entry->base.bo, intr, entry->as_mob);
599 		}
600 		if (ret)
601 			return ret;
602 
603 		/*
604 		 * Rather than having the resource code allocating the bo
605 		 * dirty tracker in resource_unreserve() where we can't fail,
606 		 * Do it here when validating the buffer object.
607 		 */
608 		if (entry->coherent_count) {
609 			unsigned int coherent_count = entry->coherent_count;
610 
611 			while (coherent_count) {
612 				ret = vmw_bo_dirty_add(vbo);
613 				if (ret)
614 					return ret;
615 
616 				coherent_count--;
617 			}
618 			entry->coherent_count -= coherent_count;
619 		}
620 
621 		if (vbo->dirty)
622 			vmw_bo_dirty_scan(vbo);
623 	}
624 	return 0;
625 }
626 
627 /**
628  * vmw_validation_res_validate - Validate all resources registered with the
629  * validation context.
630  * @ctx: The validation context.
631  * @intr: Whether to perform waits interruptible if possible.
632  *
633  * Before this function is called, all resource backup buffers must have
634  * been validated.
635  *
636  * Return: Zero on success, -ERESTARTSYS if interrupted,
637  * negative error code on failure.
638  */
639 int vmw_validation_res_validate(struct vmw_validation_context *ctx, bool intr)
640 {
641 	struct vmw_validation_res_node *val;
642 	int ret;
643 
644 	list_for_each_entry(val, &ctx->resource_list, head) {
645 		struct vmw_resource *res = val->res;
646 		struct vmw_buffer_object *backup = res->backup;
647 
648 		ret = vmw_resource_validate(res, intr, val->dirty_set &&
649 					    val->dirty);
650 		if (ret) {
651 			if (ret != -ERESTARTSYS)
652 				DRM_ERROR("Failed to validate resource.\n");
653 			return ret;
654 		}
655 
656 		/* Check if the resource switched backup buffer */
657 		if (backup && res->backup && (backup != res->backup)) {
658 			struct vmw_buffer_object *vbo = res->backup;
659 
660 			ret = vmw_validation_add_bo
661 				(ctx, vbo, vmw_resource_needs_backup(res),
662 				 false);
663 			if (ret)
664 				return ret;
665 		}
666 	}
667 	return 0;
668 }
669 
670 /**
671  * vmw_validation_drop_ht - Reset the hash table used for duplicate finding
672  * and unregister it from this validation context.
673  * @ctx: The validation context.
674  *
675  * The hash table used for duplicate finding is an expensive resource and
676  * may be protected by mutexes that may cause deadlocks during resource
677  * unreferencing if held. After resource- and buffer object registering,
678  * there is no longer any use for this hash table, so allow freeing it
679  * either to shorten any mutex locking time, or before resources- and
680  * buffer objects are freed during validation context cleanup.
681  */
682 void vmw_validation_drop_ht(struct vmw_validation_context *ctx)
683 {
684 	struct vmw_validation_bo_node *entry;
685 	struct vmw_validation_res_node *val;
686 
687 	if (!ctx->ht)
688 		return;
689 
690 	list_for_each_entry(entry, &ctx->bo_list, base.head)
691 		(void) drm_ht_remove_item(ctx->ht, &entry->hash);
692 
693 	list_for_each_entry(val, &ctx->resource_list, head)
694 		(void) drm_ht_remove_item(ctx->ht, &val->hash);
695 
696 	list_for_each_entry(val, &ctx->resource_ctx_list, head)
697 		(void) drm_ht_remove_item(ctx->ht, &val->hash);
698 
699 	ctx->ht = NULL;
700 }
701 
702 /**
703  * vmw_validation_unref_lists - Unregister previously registered buffer
704  * object and resources.
705  * @ctx: The validation context.
706  *
707  * Note that this function may cause buffer object- and resource destructors
708  * to be invoked.
709  */
710 void vmw_validation_unref_lists(struct vmw_validation_context *ctx)
711 {
712 	struct vmw_validation_bo_node *entry;
713 	struct vmw_validation_res_node *val;
714 
715 	list_for_each_entry(entry, &ctx->bo_list, base.head) {
716 		ttm_bo_put(entry->base.bo);
717 		entry->base.bo = NULL;
718 	}
719 
720 	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
721 	list_for_each_entry(val, &ctx->resource_list, head)
722 		vmw_resource_unreference(&val->res);
723 
724 	/*
725 	 * No need to detach each list entry since they are all freed with
726 	 * vmw_validation_free_mem. Just make the inaccessible.
727 	 */
728 	INIT_LIST_HEAD(&ctx->bo_list);
729 	INIT_LIST_HEAD(&ctx->resource_list);
730 
731 	vmw_validation_mem_free(ctx);
732 }
733 
734 /**
735  * vmw_validation_prepare - Prepare a validation context for command
736  * submission.
737  * @ctx: The validation context.
738  * @mutex: The mutex used to protect resource reservation.
739  * @intr: Whether to perform waits interruptible if possible.
740  *
741  * Note that the single reservation mutex @mutex is an unfortunate
742  * construct. Ideally resource reservation should be moved to per-resource
743  * ww_mutexes.
744  * If this functions doesn't return Zero to indicate success, all resources
745  * are left unreserved but still referenced.
746  * Return: Zero on success, -ERESTARTSYS if interrupted, negative error code
747  * on error.
748  */
749 int vmw_validation_prepare(struct vmw_validation_context *ctx,
750 			   struct mutex *mutex,
751 			   bool intr)
752 {
753 	int ret = 0;
754 
755 	if (mutex) {
756 		if (intr)
757 			ret = mutex_lock_interruptible(mutex);
758 		else
759 			mutex_lock(mutex);
760 		if (ret)
761 			return -ERESTARTSYS;
762 	}
763 
764 	ctx->res_mutex = mutex;
765 	ret = vmw_validation_res_reserve(ctx, intr);
766 	if (ret)
767 		goto out_no_res_reserve;
768 
769 	ret = vmw_validation_bo_reserve(ctx, intr);
770 	if (ret)
771 		goto out_no_bo_reserve;
772 
773 	ret = vmw_validation_bo_validate(ctx, intr);
774 	if (ret)
775 		goto out_no_validate;
776 
777 	ret = vmw_validation_res_validate(ctx, intr);
778 	if (ret)
779 		goto out_no_validate;
780 
781 	return 0;
782 
783 out_no_validate:
784 	vmw_validation_bo_backoff(ctx);
785 out_no_bo_reserve:
786 	vmw_validation_res_unreserve(ctx, true);
787 out_no_res_reserve:
788 	if (mutex)
789 		mutex_unlock(mutex);
790 
791 	return ret;
792 }
793 
794 /**
795  * vmw_validation_revert - Revert validation actions if command submission
796  * failed.
797  *
798  * @ctx: The validation context.
799  *
800  * The caller still needs to unref resources after a call to this function.
801  */
802 void vmw_validation_revert(struct vmw_validation_context *ctx)
803 {
804 	vmw_validation_bo_backoff(ctx);
805 	vmw_validation_res_unreserve(ctx, true);
806 	if (ctx->res_mutex)
807 		mutex_unlock(ctx->res_mutex);
808 	vmw_validation_unref_lists(ctx);
809 }
810 
811 /**
812  * vmw_validation_done - Commit validation actions after command submission
813  * success.
814  * @ctx: The validation context.
815  * @fence: Fence with which to fence all buffer objects taking part in the
816  * command submission.
817  *
818  * The caller does NOT need to unref resources after a call to this function.
819  */
820 void vmw_validation_done(struct vmw_validation_context *ctx,
821 			 struct vmw_fence_obj *fence)
822 {
823 	vmw_validation_bo_fence(ctx, fence);
824 	vmw_validation_res_unreserve(ctx, false);
825 	if (ctx->res_mutex)
826 		mutex_unlock(ctx->res_mutex);
827 	vmw_validation_unref_lists(ctx);
828 }
829 
830 /**
831  * vmw_validation_preload_bo - Preload the validation memory allocator for a
832  * call to vmw_validation_add_bo().
833  * @ctx: Pointer to the validation context.
834  *
835  * Iff this function returns successfully, the next call to
836  * vmw_validation_add_bo() is guaranteed not to sleep. An error is not fatal
837  * but voids the guarantee.
838  *
839  * Returns: Zero if successful, %-EINVAL otherwise.
840  */
841 int vmw_validation_preload_bo(struct vmw_validation_context *ctx)
842 {
843 	unsigned int size = sizeof(struct vmw_validation_bo_node);
844 
845 	if (!vmw_validation_mem_alloc(ctx, size))
846 		return -ENOMEM;
847 
848 	ctx->mem_size_left += size;
849 	return 0;
850 }
851 
852 /**
853  * vmw_validation_preload_res - Preload the validation memory allocator for a
854  * call to vmw_validation_add_res().
855  * @ctx: Pointer to the validation context.
856  * @size: Size of the validation node extra data. See below.
857  *
858  * Iff this function returns successfully, the next call to
859  * vmw_validation_add_res() with the same or smaller @size is guaranteed not to
860  * sleep. An error is not fatal but voids the guarantee.
861  *
862  * Returns: Zero if successful, %-EINVAL otherwise.
863  */
864 int vmw_validation_preload_res(struct vmw_validation_context *ctx,
865 			       unsigned int size)
866 {
867 	size = vmw_validation_align(sizeof(struct vmw_validation_res_node) +
868 				    size) +
869 		vmw_validation_align(sizeof(struct vmw_validation_bo_node));
870 	if (!vmw_validation_mem_alloc(ctx, size))
871 		return -ENOMEM;
872 
873 	ctx->mem_size_left += size;
874 	return 0;
875 }
876 
877 /**
878  * vmw_validation_bo_backoff - Unreserve buffer objects registered with a
879  * validation context
880  * @ctx: The validation context
881  *
882  * This function unreserves the buffer objects previously reserved using
883  * vmw_validation_bo_reserve. It's typically used as part of an error path
884  */
885 void vmw_validation_bo_backoff(struct vmw_validation_context *ctx)
886 {
887 	struct vmw_validation_bo_node *entry;
888 
889 	/*
890 	 * Switching coherent resource backup buffers failed.
891 	 * Release corresponding buffer object dirty trackers.
892 	 */
893 	list_for_each_entry(entry, &ctx->bo_list, base.head) {
894 		if (entry->coherent_count) {
895 			unsigned int coherent_count = entry->coherent_count;
896 			struct vmw_buffer_object *vbo =
897 				container_of(entry->base.bo, typeof(*vbo),
898 					     base);
899 
900 			while (coherent_count--)
901 				vmw_bo_dirty_release(vbo);
902 		}
903 	}
904 
905 	ttm_eu_backoff_reservation(&ctx->ticket, &ctx->bo_list);
906 }
907