xref: /linux/drivers/gpu/drm/vmwgfx/vmwgfx_cotable.c (revision bfd5bb6f90af092aa345b15cd78143956a13c2a8)
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27 /*
28  * Treat context OTables as resources to make use of the resource
29  * backing MOB eviction mechanism, that is used to read back the COTable
30  * whenever the backing MOB is evicted.
31  */
32 
33 #include <drm/ttm/ttm_placement.h>
34 
35 #include "vmwgfx_drv.h"
36 #include "vmwgfx_resource_priv.h"
37 #include "vmwgfx_so.h"
38 
39 /**
40  * struct vmw_cotable - Context Object Table resource
41  *
42  * @res: struct vmw_resource we are deriving from.
43  * @ctx: non-refcounted pointer to the owning context.
44  * @size_read_back: Size of data read back during eviction.
45  * @seen_entries: Seen entries in command stream for this cotable.
46  * @type: The cotable type.
47  * @scrubbed: Whether the cotable has been scrubbed.
48  * @resource_list: List of resources in the cotable.
49  */
50 struct vmw_cotable {
51 	struct vmw_resource res;
52 	struct vmw_resource *ctx;
53 	size_t size_read_back;
54 	int seen_entries;
55 	u32 type;
56 	bool scrubbed;
57 	struct list_head resource_list;
58 };
59 
60 /**
61  * struct vmw_cotable_info - Static info about cotable types
62  *
63  * @min_initial_entries: Min number of initial intries at cotable allocation
64  * for this cotable type.
65  * @size: Size of each entry.
66  */
67 struct vmw_cotable_info {
68 	u32 min_initial_entries;
69 	u32 size;
70 	void (*unbind_func)(struct vmw_private *, struct list_head *,
71 			    bool);
72 };
73 
74 static const struct vmw_cotable_info co_info[] = {
75 	{1, sizeof(SVGACOTableDXRTViewEntry), &vmw_view_cotable_list_destroy},
76 	{1, sizeof(SVGACOTableDXDSViewEntry), &vmw_view_cotable_list_destroy},
77 	{1, sizeof(SVGACOTableDXSRViewEntry), &vmw_view_cotable_list_destroy},
78 	{1, sizeof(SVGACOTableDXElementLayoutEntry), NULL},
79 	{1, sizeof(SVGACOTableDXBlendStateEntry), NULL},
80 	{1, sizeof(SVGACOTableDXDepthStencilEntry), NULL},
81 	{1, sizeof(SVGACOTableDXRasterizerStateEntry), NULL},
82 	{1, sizeof(SVGACOTableDXSamplerEntry), NULL},
83 	{1, sizeof(SVGACOTableDXStreamOutputEntry), NULL},
84 	{1, sizeof(SVGACOTableDXQueryEntry), NULL},
85 	{1, sizeof(SVGACOTableDXShaderEntry), &vmw_dx_shader_cotable_list_scrub}
86 };
87 
88 /*
89  * Cotables with bindings that we remove must be scrubbed first,
90  * otherwise, the device will swap in an invalid context when we remove
91  * bindings before scrubbing a cotable...
92  */
93 const SVGACOTableType vmw_cotable_scrub_order[] = {
94 	SVGA_COTABLE_RTVIEW,
95 	SVGA_COTABLE_DSVIEW,
96 	SVGA_COTABLE_SRVIEW,
97 	SVGA_COTABLE_DXSHADER,
98 	SVGA_COTABLE_ELEMENTLAYOUT,
99 	SVGA_COTABLE_BLENDSTATE,
100 	SVGA_COTABLE_DEPTHSTENCIL,
101 	SVGA_COTABLE_RASTERIZERSTATE,
102 	SVGA_COTABLE_SAMPLER,
103 	SVGA_COTABLE_STREAMOUTPUT,
104 	SVGA_COTABLE_DXQUERY,
105 };
106 
107 static int vmw_cotable_bind(struct vmw_resource *res,
108 			    struct ttm_validate_buffer *val_buf);
109 static int vmw_cotable_unbind(struct vmw_resource *res,
110 			      bool readback,
111 			      struct ttm_validate_buffer *val_buf);
112 static int vmw_cotable_create(struct vmw_resource *res);
113 static int vmw_cotable_destroy(struct vmw_resource *res);
114 
115 static const struct vmw_res_func vmw_cotable_func = {
116 	.res_type = vmw_res_cotable,
117 	.needs_backup = true,
118 	.may_evict = true,
119 	.type_name = "context guest backed object tables",
120 	.backup_placement = &vmw_mob_placement,
121 	.create = vmw_cotable_create,
122 	.destroy = vmw_cotable_destroy,
123 	.bind = vmw_cotable_bind,
124 	.unbind = vmw_cotable_unbind,
125 };
126 
127 /**
128  * vmw_cotable - Convert a struct vmw_resource pointer to a struct
129  * vmw_cotable pointer
130  *
131  * @res: Pointer to the resource.
132  */
133 static struct vmw_cotable *vmw_cotable(struct vmw_resource *res)
134 {
135 	return container_of(res, struct vmw_cotable, res);
136 }
137 
138 /**
139  * vmw_cotable_destroy - Cotable resource destroy callback
140  *
141  * @res: Pointer to the cotable resource.
142  *
143  * There is no device cotable destroy command, so this function only
144  * makes sure that the resource id is set to invalid.
145  */
146 static int vmw_cotable_destroy(struct vmw_resource *res)
147 {
148 	res->id = -1;
149 	return 0;
150 }
151 
152 /**
153  * vmw_cotable_unscrub - Undo a cotable unscrub operation
154  *
155  * @res: Pointer to the cotable resource
156  *
157  * This function issues commands to (re)bind the cotable to
158  * its backing mob, which needs to be validated and reserved at this point.
159  * This is identical to bind() except the function interface looks different.
160  */
161 static int vmw_cotable_unscrub(struct vmw_resource *res)
162 {
163 	struct vmw_cotable *vcotbl = vmw_cotable(res);
164 	struct vmw_private *dev_priv = res->dev_priv;
165 	struct ttm_buffer_object *bo = &res->backup->base;
166 	struct {
167 		SVGA3dCmdHeader header;
168 		SVGA3dCmdDXSetCOTable body;
169 	} *cmd;
170 
171 	WARN_ON_ONCE(bo->mem.mem_type != VMW_PL_MOB);
172 	lockdep_assert_held(&bo->resv->lock.base);
173 
174 	cmd = vmw_fifo_reserve_dx(dev_priv, sizeof(*cmd), SVGA3D_INVALID_ID);
175 	if (!cmd) {
176 		DRM_ERROR("Failed reserving FIFO space for cotable "
177 			  "binding.\n");
178 		return -ENOMEM;
179 	}
180 
181 	WARN_ON(vcotbl->ctx->id == SVGA3D_INVALID_ID);
182 	WARN_ON(bo->mem.mem_type != VMW_PL_MOB);
183 	cmd->header.id = SVGA_3D_CMD_DX_SET_COTABLE;
184 	cmd->header.size = sizeof(cmd->body);
185 	cmd->body.cid = vcotbl->ctx->id;
186 	cmd->body.type = vcotbl->type;
187 	cmd->body.mobid = bo->mem.start;
188 	cmd->body.validSizeInBytes = vcotbl->size_read_back;
189 
190 	vmw_fifo_commit_flush(dev_priv, sizeof(*cmd));
191 	vcotbl->scrubbed = false;
192 
193 	return 0;
194 }
195 
196 /**
197  * vmw_cotable_bind - Undo a cotable unscrub operation
198  *
199  * @res: Pointer to the cotable resource
200  * @val_buf: Pointer to a struct ttm_validate_buffer prepared by the caller
201  * for convenience / fencing.
202  *
203  * This function issues commands to (re)bind the cotable to
204  * its backing mob, which needs to be validated and reserved at this point.
205  */
206 static int vmw_cotable_bind(struct vmw_resource *res,
207 			    struct ttm_validate_buffer *val_buf)
208 {
209 	/*
210 	 * The create() callback may have changed @res->backup without
211 	 * the caller noticing, and with val_buf->bo still pointing to
212 	 * the old backup buffer. Although hackish, and not used currently,
213 	 * take the opportunity to correct the value here so that it's not
214 	 * misused in the future.
215 	 */
216 	val_buf->bo = &res->backup->base;
217 
218 	return vmw_cotable_unscrub(res);
219 }
220 
221 /**
222  * vmw_cotable_scrub - Scrub the cotable from the device.
223  *
224  * @res: Pointer to the cotable resource.
225  * @readback: Whether initiate a readback of the cotable data to the backup
226  * buffer.
227  *
228  * In some situations (context swapouts) it might be desirable to make the
229  * device forget about the cotable without performing a full unbind. A full
230  * unbind requires reserved backup buffers and it might not be possible to
231  * reserve them due to locking order violation issues. The vmw_cotable_scrub
232  * function implements a partial unbind() without that requirement but with the
233  * following restrictions.
234  * 1) Before the cotable is again used by the GPU, vmw_cotable_unscrub() must
235  *    be called.
236  * 2) Before the cotable backing buffer is used by the CPU, or during the
237  *    resource destruction, vmw_cotable_unbind() must be called.
238  */
239 int vmw_cotable_scrub(struct vmw_resource *res, bool readback)
240 {
241 	struct vmw_cotable *vcotbl = vmw_cotable(res);
242 	struct vmw_private *dev_priv = res->dev_priv;
243 	size_t submit_size;
244 
245 	struct {
246 		SVGA3dCmdHeader header;
247 		SVGA3dCmdDXReadbackCOTable body;
248 	} *cmd0;
249 	struct {
250 		SVGA3dCmdHeader header;
251 		SVGA3dCmdDXSetCOTable body;
252 	} *cmd1;
253 
254 	if (vcotbl->scrubbed)
255 		return 0;
256 
257 	if (co_info[vcotbl->type].unbind_func)
258 		co_info[vcotbl->type].unbind_func(dev_priv,
259 						  &vcotbl->resource_list,
260 						  readback);
261 	submit_size = sizeof(*cmd1);
262 	if (readback)
263 		submit_size += sizeof(*cmd0);
264 
265 	cmd1 = vmw_fifo_reserve_dx(dev_priv, submit_size, SVGA3D_INVALID_ID);
266 	if (!cmd1) {
267 		DRM_ERROR("Failed reserving FIFO space for cotable "
268 			  "unbinding.\n");
269 		return -ENOMEM;
270 	}
271 
272 	vcotbl->size_read_back = 0;
273 	if (readback) {
274 		cmd0 = (void *) cmd1;
275 		cmd0->header.id = SVGA_3D_CMD_DX_READBACK_COTABLE;
276 		cmd0->header.size = sizeof(cmd0->body);
277 		cmd0->body.cid = vcotbl->ctx->id;
278 		cmd0->body.type = vcotbl->type;
279 		cmd1 = (void *) &cmd0[1];
280 		vcotbl->size_read_back = res->backup_size;
281 	}
282 	cmd1->header.id = SVGA_3D_CMD_DX_SET_COTABLE;
283 	cmd1->header.size = sizeof(cmd1->body);
284 	cmd1->body.cid = vcotbl->ctx->id;
285 	cmd1->body.type = vcotbl->type;
286 	cmd1->body.mobid = SVGA3D_INVALID_ID;
287 	cmd1->body.validSizeInBytes = 0;
288 	vmw_fifo_commit_flush(dev_priv, submit_size);
289 	vcotbl->scrubbed = true;
290 
291 	/* Trigger a create() on next validate. */
292 	res->id = -1;
293 
294 	return 0;
295 }
296 
297 /**
298  * vmw_cotable_unbind - Cotable resource unbind callback
299  *
300  * @res: Pointer to the cotable resource.
301  * @readback: Whether to read back cotable data to the backup buffer.
302  * val_buf: Pointer to a struct ttm_validate_buffer prepared by the caller
303  * for convenience / fencing.
304  *
305  * Unbinds the cotable from the device and fences the backup buffer.
306  */
307 static int vmw_cotable_unbind(struct vmw_resource *res,
308 			      bool readback,
309 			      struct ttm_validate_buffer *val_buf)
310 {
311 	struct vmw_cotable *vcotbl = vmw_cotable(res);
312 	struct vmw_private *dev_priv = res->dev_priv;
313 	struct ttm_buffer_object *bo = val_buf->bo;
314 	struct vmw_fence_obj *fence;
315 
316 	if (list_empty(&res->mob_head))
317 		return 0;
318 
319 	WARN_ON_ONCE(bo->mem.mem_type != VMW_PL_MOB);
320 	lockdep_assert_held(&bo->resv->lock.base);
321 
322 	mutex_lock(&dev_priv->binding_mutex);
323 	if (!vcotbl->scrubbed)
324 		vmw_dx_context_scrub_cotables(vcotbl->ctx, readback);
325 	mutex_unlock(&dev_priv->binding_mutex);
326 	(void) vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
327 	vmw_fence_single_bo(bo, fence);
328 	if (likely(fence != NULL))
329 		vmw_fence_obj_unreference(&fence);
330 
331 	return 0;
332 }
333 
334 /**
335  * vmw_cotable_readback - Read back a cotable without unbinding.
336  *
337  * @res: The cotable resource.
338  *
339  * Reads back a cotable to its backing mob without scrubbing the MOB from
340  * the cotable. The MOB is fenced for subsequent CPU access.
341  */
342 static int vmw_cotable_readback(struct vmw_resource *res)
343 {
344 	struct vmw_cotable *vcotbl = vmw_cotable(res);
345 	struct vmw_private *dev_priv = res->dev_priv;
346 
347 	struct {
348 		SVGA3dCmdHeader header;
349 		SVGA3dCmdDXReadbackCOTable body;
350 	} *cmd;
351 	struct vmw_fence_obj *fence;
352 
353 	if (!vcotbl->scrubbed) {
354 		cmd = vmw_fifo_reserve_dx(dev_priv, sizeof(*cmd),
355 					  SVGA3D_INVALID_ID);
356 		if (!cmd) {
357 			DRM_ERROR("Failed reserving FIFO space for cotable "
358 				  "readback.\n");
359 			return -ENOMEM;
360 		}
361 		cmd->header.id = SVGA_3D_CMD_DX_READBACK_COTABLE;
362 		cmd->header.size = sizeof(cmd->body);
363 		cmd->body.cid = vcotbl->ctx->id;
364 		cmd->body.type = vcotbl->type;
365 		vcotbl->size_read_back = res->backup_size;
366 		vmw_fifo_commit(dev_priv, sizeof(*cmd));
367 	}
368 
369 	(void) vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
370 	vmw_fence_single_bo(&res->backup->base, fence);
371 	vmw_fence_obj_unreference(&fence);
372 
373 	return 0;
374 }
375 
376 /**
377  * vmw_cotable_resize - Resize a cotable.
378  *
379  * @res: The cotable resource.
380  * @new_size: The new size.
381  *
382  * Resizes a cotable and binds the new backup buffer.
383  * On failure the cotable is left intact.
384  * Important! This function may not fail once the MOB switch has been
385  * committed to hardware. That would put the device context in an
386  * invalid state which we can't currently recover from.
387  */
388 static int vmw_cotable_resize(struct vmw_resource *res, size_t new_size)
389 {
390 	struct ttm_operation_ctx ctx = { false, false };
391 	struct vmw_private *dev_priv = res->dev_priv;
392 	struct vmw_cotable *vcotbl = vmw_cotable(res);
393 	struct vmw_dma_buffer *buf, *old_buf = res->backup;
394 	struct ttm_buffer_object *bo, *old_bo = &res->backup->base;
395 	size_t old_size = res->backup_size;
396 	size_t old_size_read_back = vcotbl->size_read_back;
397 	size_t cur_size_read_back;
398 	struct ttm_bo_kmap_obj old_map, new_map;
399 	int ret;
400 	size_t i;
401 
402 	ret = vmw_cotable_readback(res);
403 	if (ret)
404 		return ret;
405 
406 	cur_size_read_back = vcotbl->size_read_back;
407 	vcotbl->size_read_back = old_size_read_back;
408 
409 	/*
410 	 * While device is processing, Allocate and reserve a buffer object
411 	 * for the new COTable. Initially pin the buffer object to make sure
412 	 * we can use tryreserve without failure.
413 	 */
414 	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
415 	if (!buf)
416 		return -ENOMEM;
417 
418 	ret = vmw_dmabuf_init(dev_priv, buf, new_size, &vmw_mob_ne_placement,
419 			      true, vmw_dmabuf_bo_free);
420 	if (ret) {
421 		DRM_ERROR("Failed initializing new cotable MOB.\n");
422 		return ret;
423 	}
424 
425 	bo = &buf->base;
426 	WARN_ON_ONCE(ttm_bo_reserve(bo, false, true, NULL));
427 
428 	ret = ttm_bo_wait(old_bo, false, false);
429 	if (unlikely(ret != 0)) {
430 		DRM_ERROR("Failed waiting for cotable unbind.\n");
431 		goto out_wait;
432 	}
433 
434 	/*
435 	 * Do a page by page copy of COTables. This eliminates slow vmap()s.
436 	 * This should really be a TTM utility.
437 	 */
438 	for (i = 0; i < old_bo->num_pages; ++i) {
439 		bool dummy;
440 
441 		ret = ttm_bo_kmap(old_bo, i, 1, &old_map);
442 		if (unlikely(ret != 0)) {
443 			DRM_ERROR("Failed mapping old COTable on resize.\n");
444 			goto out_wait;
445 		}
446 		ret = ttm_bo_kmap(bo, i, 1, &new_map);
447 		if (unlikely(ret != 0)) {
448 			DRM_ERROR("Failed mapping new COTable on resize.\n");
449 			goto out_map_new;
450 		}
451 		memcpy(ttm_kmap_obj_virtual(&new_map, &dummy),
452 		       ttm_kmap_obj_virtual(&old_map, &dummy),
453 		       PAGE_SIZE);
454 		ttm_bo_kunmap(&new_map);
455 		ttm_bo_kunmap(&old_map);
456 	}
457 
458 	/* Unpin new buffer, and switch backup buffers. */
459 	ret = ttm_bo_validate(bo, &vmw_mob_placement, &ctx);
460 	if (unlikely(ret != 0)) {
461 		DRM_ERROR("Failed validating new COTable backup buffer.\n");
462 		goto out_wait;
463 	}
464 
465 	res->backup = buf;
466 	res->backup_size = new_size;
467 	vcotbl->size_read_back = cur_size_read_back;
468 
469 	/*
470 	 * Now tell the device to switch. If this fails, then we need to
471 	 * revert the full resize.
472 	 */
473 	ret = vmw_cotable_unscrub(res);
474 	if (ret) {
475 		DRM_ERROR("Failed switching COTable backup buffer.\n");
476 		res->backup = old_buf;
477 		res->backup_size = old_size;
478 		vcotbl->size_read_back = old_size_read_back;
479 		goto out_wait;
480 	}
481 
482 	/* Let go of the old mob. */
483 	list_del(&res->mob_head);
484 	list_add_tail(&res->mob_head, &buf->res_list);
485 	vmw_dmabuf_unreference(&old_buf);
486 	res->id = vcotbl->type;
487 
488 	return 0;
489 
490 out_map_new:
491 	ttm_bo_kunmap(&old_map);
492 out_wait:
493 	ttm_bo_unreserve(bo);
494 	vmw_dmabuf_unreference(&buf);
495 
496 	return ret;
497 }
498 
499 /**
500  * vmw_cotable_create - Cotable resource create callback
501  *
502  * @res: Pointer to a cotable resource.
503  *
504  * There is no separate create command for cotables, so this callback, which
505  * is called before bind() in the validation sequence is instead used for two
506  * things.
507  * 1) Unscrub the cotable if it is scrubbed and still attached to a backup
508  *    buffer, that is, if @res->mob_head is non-empty.
509  * 2) Resize the cotable if needed.
510  */
511 static int vmw_cotable_create(struct vmw_resource *res)
512 {
513 	struct vmw_cotable *vcotbl = vmw_cotable(res);
514 	size_t new_size = res->backup_size;
515 	size_t needed_size;
516 	int ret;
517 
518 	/* Check whether we need to resize the cotable */
519 	needed_size = (vcotbl->seen_entries + 1) * co_info[vcotbl->type].size;
520 	while (needed_size > new_size)
521 		new_size *= 2;
522 
523 	if (likely(new_size <= res->backup_size)) {
524 		if (vcotbl->scrubbed && !list_empty(&res->mob_head)) {
525 			ret = vmw_cotable_unscrub(res);
526 			if (ret)
527 				return ret;
528 		}
529 		res->id = vcotbl->type;
530 		return 0;
531 	}
532 
533 	return vmw_cotable_resize(res, new_size);
534 }
535 
536 /**
537  * vmw_hw_cotable_destroy - Cotable hw_destroy callback
538  *
539  * @res: Pointer to a cotable resource.
540  *
541  * The final (part of resource destruction) destroy callback.
542  */
543 static void vmw_hw_cotable_destroy(struct vmw_resource *res)
544 {
545 	(void) vmw_cotable_destroy(res);
546 }
547 
548 static size_t cotable_acc_size;
549 
550 /**
551  * vmw_cotable_free - Cotable resource destructor
552  *
553  * @res: Pointer to a cotable resource.
554  */
555 static void vmw_cotable_free(struct vmw_resource *res)
556 {
557 	struct vmw_private *dev_priv = res->dev_priv;
558 
559 	kfree(res);
560 	ttm_mem_global_free(vmw_mem_glob(dev_priv), cotable_acc_size);
561 }
562 
563 /**
564  * vmw_cotable_alloc - Create a cotable resource
565  *
566  * @dev_priv: Pointer to a device private struct.
567  * @ctx: Pointer to the context resource.
568  * The cotable resource will not add a refcount.
569  * @type: The cotable type.
570  */
571 struct vmw_resource *vmw_cotable_alloc(struct vmw_private *dev_priv,
572 				       struct vmw_resource *ctx,
573 				       u32 type)
574 {
575 	struct vmw_cotable *vcotbl;
576 	struct ttm_operation_ctx ttm_opt_ctx = {
577 		.interruptible = true,
578 		.no_wait_gpu = false
579 	};
580 	int ret;
581 	u32 num_entries;
582 
583 	if (unlikely(cotable_acc_size == 0))
584 		cotable_acc_size = ttm_round_pot(sizeof(struct vmw_cotable));
585 
586 	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
587 				   cotable_acc_size, &ttm_opt_ctx);
588 	if (unlikely(ret))
589 		return ERR_PTR(ret);
590 
591 	vcotbl = kzalloc(sizeof(*vcotbl), GFP_KERNEL);
592 	if (unlikely(!vcotbl)) {
593 		ret = -ENOMEM;
594 		goto out_no_alloc;
595 	}
596 
597 	ret = vmw_resource_init(dev_priv, &vcotbl->res, true,
598 				vmw_cotable_free, &vmw_cotable_func);
599 	if (unlikely(ret != 0))
600 		goto out_no_init;
601 
602 	INIT_LIST_HEAD(&vcotbl->resource_list);
603 	vcotbl->res.id = type;
604 	vcotbl->res.backup_size = PAGE_SIZE;
605 	num_entries = PAGE_SIZE / co_info[type].size;
606 	if (num_entries < co_info[type].min_initial_entries) {
607 		vcotbl->res.backup_size = co_info[type].min_initial_entries *
608 			co_info[type].size;
609 		vcotbl->res.backup_size =
610 			(vcotbl->res.backup_size + PAGE_SIZE - 1) & PAGE_MASK;
611 	}
612 
613 	vcotbl->scrubbed = true;
614 	vcotbl->seen_entries = -1;
615 	vcotbl->type = type;
616 	vcotbl->ctx = ctx;
617 
618 	vmw_resource_activate(&vcotbl->res, vmw_hw_cotable_destroy);
619 
620 	return &vcotbl->res;
621 
622 out_no_init:
623 	kfree(vcotbl);
624 out_no_alloc:
625 	ttm_mem_global_free(vmw_mem_glob(dev_priv), cotable_acc_size);
626 	return ERR_PTR(ret);
627 }
628 
629 /**
630  * vmw_cotable_notify - Notify the cotable about an item creation
631  *
632  * @res: Pointer to a cotable resource.
633  * @id: Item id.
634  */
635 int vmw_cotable_notify(struct vmw_resource *res, int id)
636 {
637 	struct vmw_cotable *vcotbl = vmw_cotable(res);
638 
639 	if (id < 0 || id >= SVGA_COTABLE_MAX_IDS) {
640 		DRM_ERROR("Illegal COTable id. Type is %u. Id is %d\n",
641 			  (unsigned) vcotbl->type, id);
642 		return -EINVAL;
643 	}
644 
645 	if (vcotbl->seen_entries < id) {
646 		/* Trigger a call to create() on next validate */
647 		res->id = -1;
648 		vcotbl->seen_entries = id;
649 	}
650 
651 	return 0;
652 }
653 
654 /**
655  * vmw_cotable_add_view - add a view to the cotable's list of active views.
656  *
657  * @res: pointer struct vmw_resource representing the cotable.
658  * @head: pointer to the struct list_head member of the resource, dedicated
659  * to the cotable active resource list.
660  */
661 void vmw_cotable_add_resource(struct vmw_resource *res, struct list_head *head)
662 {
663 	struct vmw_cotable *vcotbl =
664 		container_of(res, struct vmw_cotable, res);
665 
666 	list_add_tail(head, &vcotbl->resource_list);
667 }
668