drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c - third_party/linux - Git at Google

 /**************************************************************************
  *
  * Copyright © 2011-2015 VMware, Inc., Palo Alto, CA., USA
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sub license, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial portions
  * of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  **************************************************************************/

 #include <drm/ttm/ttm_placement.h>

 #include <drm/drmP.h>
 #include "vmwgfx_drv.h"


 /**
  * vmw_dmabuf_pin_in_placement - Validate a buffer to placement.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
  * @placement:  The placement to pin it.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  *  -ERESTARTSYS if interrupted by a signal.
  */
 int vmw_dmabuf_pin_in_placement(struct vmw_private *dev_priv,
 				struct vmw_dma_buffer *buf,
 				struct ttm_placement *placement,
 				bool interruptible)
 {
 	struct ttm_operation_ctx ctx = {interruptible, false };
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
 	uint32_t new_flags;

 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
 		return ret;

 	vmw_execbuf_release_pinned_bo(dev_priv);

 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
 		goto err;

 	if (buf->pin_count > 0)
 		ret = ttm_bo_mem_compat(placement, &bo->mem,
 					&new_flags) == true ? 0 : -EINVAL;
 	else
 		ret = ttm_bo_validate(bo, placement, &ctx);

 	if (!ret)
 		vmw_bo_pin_reserved(buf, true);

 	ttm_bo_unreserve(bo);

 err:
 	ttm_write_unlock(&dev_priv->reservation_sem);
 	return ret;
 }

 /**
  * vmw_dmabuf_pin_in_vram_or_gmr - Move a buffer to vram or gmr.
  *
  * This function takes the reservation_sem in write mode.
  * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
  * @pin:  Pin buffer if true.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
 int vmw_dmabuf_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
 				  struct vmw_dma_buffer *buf,
 				  bool interruptible)
 {
 	struct ttm_operation_ctx ctx = {interruptible, false };
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;
 	uint32_t new_flags;

 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
 		return ret;

 	vmw_execbuf_release_pinned_bo(dev_priv);

 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
 		goto err;

 	if (buf->pin_count > 0) {
 		ret = ttm_bo_mem_compat(&vmw_vram_gmr_placement, &bo->mem,
 					&new_flags) == true ? 0 : -EINVAL;
 		goto out_unreserve;
 	}

 	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, &ctx);
 	if (likely(ret == 0) || ret == -ERESTARTSYS)
 		goto out_unreserve;

 	ret = ttm_bo_validate(bo, &vmw_vram_placement, &ctx);

 out_unreserve:
 	if (!ret)
 		vmw_bo_pin_reserved(buf, true);

 	ttm_bo_unreserve(bo);
 err:
 	ttm_write_unlock(&dev_priv->reservation_sem);
 	return ret;
 }

 /**
  * vmw_dmabuf_pin_in_vram - Move a buffer to vram.
  *
  * This function takes the reservation_sem in write mode.
  * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to move.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
 int vmw_dmabuf_pin_in_vram(struct vmw_private *dev_priv,
 			   struct vmw_dma_buffer *buf,
 			   bool interruptible)
 {
 	return vmw_dmabuf_pin_in_placement(dev_priv, buf, &vmw_vram_placement,
 					   interruptible);
 }

 /**
  * vmw_dmabuf_pin_in_start_of_vram - Move a buffer to start of vram.
  *
  * This function takes the reservation_sem in write mode.
  * Flushes and unpins the query bo to avoid failures.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to pin.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
 int vmw_dmabuf_pin_in_start_of_vram(struct vmw_private *dev_priv,
 				    struct vmw_dma_buffer *buf,
 				    bool interruptible)
 {
 	struct ttm_operation_ctx ctx = {interruptible, false };
 	struct ttm_buffer_object *bo = &buf->base;
 	struct ttm_placement placement;
 	struct ttm_place place;
 	int ret = 0;
 	uint32_t new_flags;

 	place = vmw_vram_placement.placement[0];
 	place.lpfn = bo->num_pages;
 	placement.num_placement = 1;
 	placement.placement = &place;
 	placement.num_busy_placement = 1;
 	placement.busy_placement = &place;

 	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
 		return ret;

 	vmw_execbuf_release_pinned_bo(dev_priv);
 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
 		goto err_unlock;

 	/*
 	 * Is this buffer already in vram but not at the start of it?
 	 * In that case, evict it first because TTM isn't good at handling
 	 * that situation.
 	 */
 	if (bo->mem.mem_type == TTM_PL_VRAM &&
 	    bo->mem.start < bo->num_pages &&
 	    bo->mem.start > 0 &&
 	    buf->pin_count == 0) {
 		ctx.interruptible = false;
 		(void) ttm_bo_validate(bo, &vmw_sys_placement, &ctx);
 	}

 	if (buf->pin_count > 0)
 		ret = ttm_bo_mem_compat(&placement, &bo->mem,
 					&new_flags) == true ? 0 : -EINVAL;
 	else
 		ret = ttm_bo_validate(bo, &placement, &ctx);

 	/* For some reason we didn't end up at the start of vram */
 	WARN_ON(ret == 0 && bo->offset != 0);
 	if (!ret)
 		vmw_bo_pin_reserved(buf, true);

 	ttm_bo_unreserve(bo);
 err_unlock:
 	ttm_write_unlock(&dev_priv->reservation_sem);

 	return ret;
 }

 /**
  * vmw_dmabuf_unpin - Unpin the buffer given buffer, does not move the buffer.
  *
  * This function takes the reservation_sem in write mode.
  *
  * @dev_priv:  Driver private.
  * @buf:  DMA buffer to unpin.
  * @interruptible:  Use interruptible wait.
  *
  * Returns
  * -ERESTARTSYS if interrupted by a signal.
  */
 int vmw_dmabuf_unpin(struct vmw_private *dev_priv,
 		     struct vmw_dma_buffer *buf,
 		     bool interruptible)
 {
 	struct ttm_buffer_object *bo = &buf->base;
 	int ret;

 	ret = ttm_read_lock(&dev_priv->reservation_sem, interruptible);
 	if (unlikely(ret != 0))
 		return ret;

 	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
 	if (unlikely(ret != 0))
 		goto err;

 	vmw_bo_pin_reserved(buf, false);

 	ttm_bo_unreserve(bo);

 err:
 	ttm_read_unlock(&dev_priv->reservation_sem);
 	return ret;
 }

 /**
  * vmw_bo_get_guest_ptr - Get the guest ptr representing the current placement
  * of a buffer.
  *
  * @bo: Pointer to a struct ttm_buffer_object. Must be pinned or reserved.
  * @ptr: SVGAGuestPtr returning the result.
  */
 void vmw_bo_get_guest_ptr(const struct ttm_buffer_object *bo,
 			  SVGAGuestPtr *ptr)
 {
 	if (bo->mem.mem_type == TTM_PL_VRAM) {
 		ptr->gmrId = SVGA_GMR_FRAMEBUFFER;
 		ptr->offset = bo->offset;
 	} else {
 		ptr->gmrId = bo->mem.start;
 		ptr->offset = 0;
 	}
 }


 /**
  * vmw_bo_pin_reserved - Pin or unpin a buffer object without moving it.
  *
  * @vbo: The buffer object. Must be reserved.
  * @pin: Whether to pin or unpin.
  *
  */
 void vmw_bo_pin_reserved(struct vmw_dma_buffer *vbo, bool pin)
 {
 	struct ttm_operation_ctx ctx = { false, true };
 	struct ttm_place pl;
 	struct ttm_placement placement;
 	struct ttm_buffer_object *bo = &vbo->base;
 	uint32_t old_mem_type = bo->mem.mem_type;
 	int ret;

 	lockdep_assert_held(&bo->resv->lock.base);

 	if (pin) {
 		if (vbo->pin_count++ > 0)
 			return;
 	} else {
 		WARN_ON(vbo->pin_count <= 0);
 		if (--vbo->pin_count > 0)
 			return;
 	}

 	pl.fpfn = 0;
 	pl.lpfn = 0;
 	pl.flags = TTM_PL_FLAG_VRAM | VMW_PL_FLAG_GMR | VMW_PL_FLAG_MOB
 		| TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED;
 	if (pin)
 		pl.flags |= TTM_PL_FLAG_NO_EVICT;

 	memset(&placement, 0, sizeof(placement));
 	placement.num_placement = 1;
 	placement.placement = &pl;

 	ret = ttm_bo_validate(bo, &placement, &ctx);

 	BUG_ON(ret != 0 || bo->mem.mem_type != old_mem_type);
 }


 /*
  * vmw_dma_buffer_unmap - Tear down a cached buffer object map.
  *
  * @vbo: The buffer object whose map we are tearing down.
  *
  * This function tears down a cached map set up using
  * vmw_dma_buffer_map_and_cache().
  */
 void vmw_dma_buffer_unmap(struct vmw_dma_buffer *vbo)
 {
 	if (vbo->map.bo == NULL)
 		return;

 	ttm_bo_kunmap(&vbo->map);
 }


 /*
  * vmw_dma_buffer_map_and_cache - Map a buffer object and cache the map
  *
  * @vbo: The buffer object to map
  * Return: A kernel virtual address or NULL if mapping failed.
  *
  * This function maps a buffer object into the kernel address space, or
  * returns the virtual kernel address of an already existing map. The virtual
  * address remains valid as long as the buffer object is pinned or reserved.
  * The cached map is torn down on either
  * 1) Buffer object move
  * 2) Buffer object swapout
  * 3) Buffer object destruction
  *
  */
 void *vmw_dma_buffer_map_and_cache(struct vmw_dma_buffer *vbo)
 {
 	struct ttm_buffer_object *bo = &vbo->base;
 	bool not_used;
 	void *virtual;
 	int ret;

 	virtual = ttm_kmap_obj_virtual(&vbo->map, &not_used);
 	if (virtual)
 		return virtual;

 	ret = ttm_bo_kmap(bo, 0, bo->num_pages, &vbo->map);
 	if (ret)
 		DRM_ERROR("Buffer object map failed: %d.\n", ret);

 	return ttm_kmap_obj_virtual(&vbo->map, &not_used);
 }
	/**************************************************************************
	*
	* Copyright © 2011-2015 VMware, Inc., Palo Alto, CA., USA
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sub license, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial portions
	* of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	*
	**************************************************************************/

	#include <drm/ttm/ttm_placement.h>

	#include <drm/drmP.h>
	#include "vmwgfx_drv.h"


	/**
	* vmw_dmabuf_pin_in_placement - Validate a buffer to placement.
	*
	* @dev_priv: Driver private.
	* @buf: DMA buffer to move.
	* @placement: The placement to pin it.
	* @interruptible: Use interruptible wait.
	*
	* Returns
	* -ERESTARTSYS if interrupted by a signal.
	*/
	int vmw_dmabuf_pin_in_placement(struct vmw_private *dev_priv,
	struct vmw_dma_buffer *buf,
	struct ttm_placement *placement,
	bool interruptible)
	{
	struct ttm_operation_ctx ctx = {interruptible, false };
	struct ttm_buffer_object *bo = &buf->base;
	int ret;
	uint32_t new_flags;

	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
	if (unlikely(ret != 0))
	return ret;

	vmw_execbuf_release_pinned_bo(dev_priv);

	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
	if (unlikely(ret != 0))
	goto err;

	if (buf->pin_count > 0)
	ret = ttm_bo_mem_compat(placement, &bo->mem,
	&new_flags) == true ? 0 : -EINVAL;
	else
	ret = ttm_bo_validate(bo, placement, &ctx);

	if (!ret)
	vmw_bo_pin_reserved(buf, true);

	ttm_bo_unreserve(bo);

	err:
	ttm_write_unlock(&dev_priv->reservation_sem);
	return ret;
	}

	/**
	* vmw_dmabuf_pin_in_vram_or_gmr - Move a buffer to vram or gmr.
	*
	* This function takes the reservation_sem in write mode.
	* Flushes and unpins the query bo to avoid failures.
	*
	* @dev_priv: Driver private.
	* @buf: DMA buffer to move.
	* @pin: Pin buffer if true.
	* @interruptible: Use interruptible wait.
	*
	* Returns
	* -ERESTARTSYS if interrupted by a signal.
	*/
	int vmw_dmabuf_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
	struct vmw_dma_buffer *buf,
	bool interruptible)
	{
	struct ttm_operation_ctx ctx = {interruptible, false };
	struct ttm_buffer_object *bo = &buf->base;
	int ret;
	uint32_t new_flags;

	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
	if (unlikely(ret != 0))
	return ret;

	vmw_execbuf_release_pinned_bo(dev_priv);

	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
	if (unlikely(ret != 0))
	goto err;

	if (buf->pin_count > 0) {
	ret = ttm_bo_mem_compat(&vmw_vram_gmr_placement, &bo->mem,
	&new_flags) == true ? 0 : -EINVAL;
	goto out_unreserve;
	}

	ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, &ctx);
	if (likely(ret == 0) \|\| ret == -ERESTARTSYS)
	goto out_unreserve;

	ret = ttm_bo_validate(bo, &vmw_vram_placement, &ctx);

	out_unreserve:
	if (!ret)
	vmw_bo_pin_reserved(buf, true);

	ttm_bo_unreserve(bo);
	err:
	ttm_write_unlock(&dev_priv->reservation_sem);
	return ret;
	}

	/**
	* vmw_dmabuf_pin_in_vram - Move a buffer to vram.
	*
	* This function takes the reservation_sem in write mode.
	* Flushes and unpins the query bo to avoid failures.
	*
	* @dev_priv: Driver private.
	* @buf: DMA buffer to move.
	* @interruptible: Use interruptible wait.
	*
	* Returns
	* -ERESTARTSYS if interrupted by a signal.
	*/
	int vmw_dmabuf_pin_in_vram(struct vmw_private *dev_priv,
	struct vmw_dma_buffer *buf,
	bool interruptible)
	{
	return vmw_dmabuf_pin_in_placement(dev_priv, buf, &vmw_vram_placement,
	interruptible);
	}

	/**
	* vmw_dmabuf_pin_in_start_of_vram - Move a buffer to start of vram.
	*
	* This function takes the reservation_sem in write mode.
	* Flushes and unpins the query bo to avoid failures.
	*
	* @dev_priv: Driver private.
	* @buf: DMA buffer to pin.
	* @interruptible: Use interruptible wait.
	*
	* Returns
	* -ERESTARTSYS if interrupted by a signal.
	*/
	int vmw_dmabuf_pin_in_start_of_vram(struct vmw_private *dev_priv,
	struct vmw_dma_buffer *buf,
	bool interruptible)
	{
	struct ttm_operation_ctx ctx = {interruptible, false };
	struct ttm_buffer_object *bo = &buf->base;
	struct ttm_placement placement;
	struct ttm_place place;
	int ret = 0;
	uint32_t new_flags;

	place = vmw_vram_placement.placement[0];
	place.lpfn = bo->num_pages;
	placement.num_placement = 1;
	placement.placement = &place;
	placement.num_busy_placement = 1;
	placement.busy_placement = &place;

	ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
	if (unlikely(ret != 0))
	return ret;

	vmw_execbuf_release_pinned_bo(dev_priv);
	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
	if (unlikely(ret != 0))
	goto err_unlock;

	/*
	* Is this buffer already in vram but not at the start of it?
	* In that case, evict it first because TTM isn't good at handling
	* that situation.
	*/
	if (bo->mem.mem_type == TTM_PL_VRAM &&
	bo->mem.start < bo->num_pages &&
	bo->mem.start > 0 &&
	buf->pin_count == 0) {
	ctx.interruptible = false;
	(void) ttm_bo_validate(bo, &vmw_sys_placement, &ctx);
	}

	if (buf->pin_count > 0)
	ret = ttm_bo_mem_compat(&placement, &bo->mem,
	&new_flags) == true ? 0 : -EINVAL;
	else
	ret = ttm_bo_validate(bo, &placement, &ctx);

	/* For some reason we didn't end up at the start of vram */
	WARN_ON(ret == 0 && bo->offset != 0);
	if (!ret)
	vmw_bo_pin_reserved(buf, true);

	ttm_bo_unreserve(bo);
	err_unlock:
	ttm_write_unlock(&dev_priv->reservation_sem);

	return ret;
	}

	/**
	* vmw_dmabuf_unpin - Unpin the buffer given buffer, does not move the buffer.
	*
	* This function takes the reservation_sem in write mode.
	*
	* @dev_priv: Driver private.
	* @buf: DMA buffer to unpin.
	* @interruptible: Use interruptible wait.
	*
	* Returns
	* -ERESTARTSYS if interrupted by a signal.
	*/
	int vmw_dmabuf_unpin(struct vmw_private *dev_priv,
	struct vmw_dma_buffer *buf,
	bool interruptible)
	{
	struct ttm_buffer_object *bo = &buf->base;
	int ret;

	ret = ttm_read_lock(&dev_priv->reservation_sem, interruptible);
	if (unlikely(ret != 0))
	return ret;

	ret = ttm_bo_reserve(bo, interruptible, false, NULL);
	if (unlikely(ret != 0))
	goto err;

	vmw_bo_pin_reserved(buf, false);

	ttm_bo_unreserve(bo);

	err:
	ttm_read_unlock(&dev_priv->reservation_sem);
	return ret;
	}

	/**
	* vmw_bo_get_guest_ptr - Get the guest ptr representing the current placement
	* of a buffer.
	*
	* @bo: Pointer to a struct ttm_buffer_object. Must be pinned or reserved.
	* @ptr: SVGAGuestPtr returning the result.
	*/
	void vmw_bo_get_guest_ptr(const struct ttm_buffer_object *bo,
	SVGAGuestPtr *ptr)
	{
	if (bo->mem.mem_type == TTM_PL_VRAM) {
	ptr->gmrId = SVGA_GMR_FRAMEBUFFER;
	ptr->offset = bo->offset;
	} else {
	ptr->gmrId = bo->mem.start;
	ptr->offset = 0;
	}
	}


	/**
	* vmw_bo_pin_reserved - Pin or unpin a buffer object without moving it.
	*
	* @vbo: The buffer object. Must be reserved.
	* @pin: Whether to pin or unpin.
	*
	*/
	void vmw_bo_pin_reserved(struct vmw_dma_buffer *vbo, bool pin)
	{
	struct ttm_operation_ctx ctx = { false, true };
	struct ttm_place pl;
	struct ttm_placement placement;
	struct ttm_buffer_object *bo = &vbo->base;
	uint32_t old_mem_type = bo->mem.mem_type;
	int ret;

	lockdep_assert_held(&bo->resv->lock.base);

	if (pin) {
	if (vbo->pin_count++ > 0)
	return;
	} else {
	WARN_ON(vbo->pin_count <= 0);
	if (--vbo->pin_count > 0)
	return;
	}

	pl.fpfn = 0;
	pl.lpfn = 0;
	pl.flags = TTM_PL_FLAG_VRAM \| VMW_PL_FLAG_GMR \| VMW_PL_FLAG_MOB
	\| TTM_PL_FLAG_SYSTEM \| TTM_PL_FLAG_CACHED;
	if (pin)
	pl.flags \|= TTM_PL_FLAG_NO_EVICT;

	memset(&placement, 0, sizeof(placement));
	placement.num_placement = 1;
	placement.placement = &pl;

	ret = ttm_bo_validate(bo, &placement, &ctx);

	BUG_ON(ret != 0 \|\| bo->mem.mem_type != old_mem_type);
	}


	/*
	* vmw_dma_buffer_unmap - Tear down a cached buffer object map.
	*
	* @vbo: The buffer object whose map we are tearing down.
	*
	* This function tears down a cached map set up using
	* vmw_dma_buffer_map_and_cache().
	*/
	void vmw_dma_buffer_unmap(struct vmw_dma_buffer *vbo)
	{
	if (vbo->map.bo == NULL)
	return;

	ttm_bo_kunmap(&vbo->map);
	}


	/*
	* vmw_dma_buffer_map_and_cache - Map a buffer object and cache the map
	*
	* @vbo: The buffer object to map
	* Return: A kernel virtual address or NULL if mapping failed.
	*
	* This function maps a buffer object into the kernel address space, or
	* returns the virtual kernel address of an already existing map. The virtual
	* address remains valid as long as the buffer object is pinned or reserved.
	* The cached map is torn down on either
	* 1) Buffer object move
	* 2) Buffer object swapout
	* 3) Buffer object destruction
	*
	*/
	void vmw_dma_buffer_map_and_cache(struct vmw_dma_buffer vbo)
	{
	struct ttm_buffer_object *bo = &vbo->base;
	bool not_used;
	void *virtual;
	int ret;

	virtual = ttm_kmap_obj_virtual(&vbo->map, &not_used);
	if (virtual)
	return virtual;

	ret = ttm_bo_kmap(bo, 0, bo->num_pages, &vbo->map);
	if (ret)
	DRM_ERROR("Buffer object map failed: %d.\n", ret);

	return ttm_kmap_obj_virtual(&vbo->map, &not_used);
	}