drm/vmwgfx/vmwgfx_resource.c

/**************************************************************************
 *
 * Copyright © 2009-2015 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 "vmwgfx_drv.h"
#include <drm/vmwgfx_drm.h>
#include <drm/ttm/ttm_object.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/drmP.h>
#include "vmwgfx_resource_priv.h"
#include "vmwgfx_binding.h"

#define VMW_RES_EVICT_ERR_COUNT 10

struct vmw_user_dma_buffer {
	struct ttm_prime_object prime;
	struct vmw_dma_buffer dma;
};

struct vmw_bo_user_rep {
	uint32_t handle;
	uint64_t map_handle;
};

static inline struct vmw_dma_buffer *
vmw_dma_buffer(struct ttm_buffer_object *bo)
{
	return container_of(bo, struct vmw_dma_buffer, base);
}

static inline struct vmw_user_dma_buffer *
vmw_user_dma_buffer(struct ttm_buffer_object *bo)
{
	struct vmw_dma_buffer *vmw_bo = vmw_dma_buffer(bo);
	return container_of(vmw_bo, struct vmw_user_dma_buffer, dma);
}

struct vmw_resource *vmw_resource_reference(struct vmw_resource *res)
{
	kref_get(&res->kref);
	return res;
}

struct vmw_resource *
vmw_resource_reference_unless_doomed(struct vmw_resource *res)
{
	return kref_get_unless_zero(&res->kref) ? res : NULL;
}

/**
 * vmw_resource_release_id - release a resource id to the id manager.
 *
 * @res: Pointer to the resource.
 *
 * Release the resource id to the resource id manager and set it to -1
 */
void vmw_resource_release_id(struct vmw_resource *res)
{
	struct vmw_private *dev_priv = res->dev_priv;
	struct idr *idr = &dev_priv->res_idr[res->func->res_type];

	write_lock(&dev_priv->resource_lock);
	if (res->id != -1)
		idr_remove(idr, res->id);
	res->id = -1;
	write_unlock(&dev_priv->resource_lock);
}

static void vmw_resource_release(struct kref *kref)
{
	struct vmw_resource *res =
	    container_of(kref, struct vmw_resource, kref);
	struct vmw_private *dev_priv = res->dev_priv;
	int id;
	struct idr *idr = &dev_priv->res_idr[res->func->res_type];

	write_lock(&dev_priv->resource_lock);
	res->avail = false;
	list_del_init(&res->lru_head);
	write_unlock(&dev_priv->resource_lock);
	if (res->backup) {
		struct ttm_buffer_object *bo = &res->backup->base;

		ttm_bo_reserve(bo, false, false, NULL);
		if (!list_empty(&res->mob_head) &&
		    res->func->unbind != NULL) {
			struct ttm_validate_buffer val_buf;

			val_buf.bo = bo;
			val_buf.shared = false;
			res->func->unbind(res, false, &val_buf);
		}
		res->backup_dirty = false;
		list_del_init(&res->mob_head);
		ttm_bo_unreserve(bo);
		vmw_dmabuf_unreference(&res->backup);
	}

	if (likely(res->hw_destroy != NULL)) {
		mutex_lock(&dev_priv->binding_mutex);
		vmw_binding_res_list_kill(&res->binding_head);
		mutex_unlock(&dev_priv->binding_mutex);
		res->hw_destroy(res);
	}

	id = res->id;
	if (res->res_free != NULL)
		res->res_free(res);
	else
		kfree(res);

	write_lock(&dev_priv->resource_lock);
	if (id != -1)
		idr_remove(idr, id);
	write_unlock(&dev_priv->resource_lock);
}

void vmw_resource_unreference(struct vmw_resource **p_res)
{
	struct vmw_resource *res = *p_res;

	*p_res = NULL;
	kref_put(&res->kref, vmw_resource_release);
}


/**
 * vmw_resource_alloc_id - release a resource id to the id manager.
 *
 * @res: Pointer to the resource.
 *
 * Allocate the lowest free resource from the resource manager, and set
 * @res->id to that id. Returns 0 on success and -ENOMEM on failure.
 */
int vmw_resource_alloc_id(struct vmw_resource *res)
{
	struct vmw_private *dev_priv = res->dev_priv;
	int ret;
	struct idr *idr = &dev_priv->res_idr[res->func->res_type];

	BUG_ON(res->id != -1);

	idr_preload(GFP_KERNEL);
	write_lock(&dev_priv->resource_lock);

	ret = idr_alloc(idr, res, 1, 0, GFP_NOWAIT);
	if (ret >= 0)
		res->id = ret;

	write_unlock(&dev_priv->resource_lock);
	idr_preload_end();
	return ret < 0 ? ret : 0;
}

/**
 * vmw_resource_init - initialize a struct vmw_resource
 *
 * @dev_priv:       Pointer to a device private struct.
 * @res:            The struct vmw_resource to initialize.
 * @obj_type:       Resource object type.
 * @delay_id:       Boolean whether to defer device id allocation until
 *                  the first validation.
 * @res_free:       Resource destructor.
 * @func:           Resource function table.
 */
int vmw_resource_init(struct vmw_private *dev_priv, struct vmw_resource *res,
		      bool delay_id,
		      void (*res_free) (struct vmw_resource *res),
		      const struct vmw_res_func *func)
{
	kref_init(&res->kref);
	res->hw_destroy = NULL;
	res->res_free = res_free;
	res->avail = false;
	res->dev_priv = dev_priv;
	res->func = func;
	INIT_LIST_HEAD(&res->lru_head);
	INIT_LIST_HEAD(&res->mob_head);
	INIT_LIST_HEAD(&res->binding_head);
	res->id = -1;
	res->backup = NULL;
	res->backup_offset = 0;
	res->backup_dirty = false;
	res->res_dirty = false;
	if (delay_id)
		return 0;
	else
		return vmw_resource_alloc_id(res);
}

/**
 * vmw_resource_activate
 *
 * @res:        Pointer to the newly created resource
 * @hw_destroy: Destroy function. NULL if none.
 *
 * Activate a resource after the hardware has been made aware of it.
 * Set tye destroy function to @destroy. Typically this frees the
 * resource and destroys the hardware resources associated with it.
 * Activate basically means that the function vmw_resource_lookup will
 * find it.
 */
void vmw_resource_activate(struct vmw_resource *res,
			   void (*hw_destroy) (struct vmw_resource *))
{
	struct vmw_private *dev_priv = res->dev_priv;

	write_lock(&dev_priv->resource_lock);
	res->avail = true;
	res->hw_destroy = hw_destroy;
	write_unlock(&dev_priv->resource_lock);
}

/**
 * vmw_user_resource_lookup_handle - lookup a struct resource from a
 * TTM user-space handle and perform basic type checks
 *
 * @dev_priv:     Pointer to a device private struct
 * @tfile:        Pointer to a struct ttm_object_file identifying the caller
 * @handle:       The TTM user-space handle
 * @converter:    Pointer to an object describing the resource type
 * @p_res:        On successful return the location pointed to will contain
 *                a pointer to a refcounted struct vmw_resource.
 *
 * If the handle can't be found or is associated with an incorrect resource
 * type, -EINVAL will be returned.
 */
int vmw_user_resource_lookup_handle(struct vmw_private *dev_priv,
				    struct ttm_object_file *tfile,
				    uint32_t handle,
				    const struct vmw_user_resource_conv
				    *converter,
				    struct vmw_resource **p_res)
{
	struct ttm_base_object *base;
	struct vmw_resource *res;
	int ret = -EINVAL;

	base = ttm_base_object_lookup(tfile, handle);
	if (unlikely(base == NULL))
		return -EINVAL;

	if (unlikely(ttm_base_object_type(base) != converter->object_type))
		goto out_bad_resource;

	res = converter->base_obj_to_res(base);

	read_lock(&dev_priv->resource_lock);
	if (!res->avail || res->res_free != converter->res_free) {
		read_unlock(&dev_priv->resource_lock);
		goto out_bad_resource;
	}

	kref_get(&res->kref);
	read_unlock(&dev_priv->resource_lock);

	*p_res = res;
	ret = 0;

out_bad_resource:
	ttm_base_object_unref(&base);

	return ret;
}

/**
 * Helper function that looks either a surface or dmabuf.
 *
 * The pointer this pointed at by out_surf and out_buf needs to be null.
 */
int vmw_user_lookup_handle(struct vmw_private *dev_priv,
			   struct ttm_object_file *tfile,
			   uint32_t handle,
			   struct vmw_surface **out_surf,
			   struct vmw_dma_buffer **out_buf)
{
	struct vmw_resource *res;
	int ret;

	BUG_ON(*out_surf || *out_buf);

	ret = vmw_user_resource_lookup_handle(dev_priv, tfile, handle,
					      user_surface_converter,
					      &res);
	if (!ret) {
		*out_surf = vmw_res_to_srf(res);
		return 0;
	}

	*out_surf = NULL;
	ret = vmw_user_dmabuf_lookup(tfile, handle, out_buf, NULL);
	return ret;
}

/**
 * Buffer management.
 */

/**
 * vmw_dmabuf_acc_size - Calculate the pinned memory usage of buffers
 *
 * @dev_priv: Pointer to a struct vmw_private identifying the device.
 * @size: The requested buffer size.
 * @user: Whether this is an ordinary dma buffer or a user dma buffer.
 */
static size_t vmw_dmabuf_acc_size(struct vmw_private *dev_priv, size_t size,
				  bool user)
{
	static size_t struct_size, user_struct_size;
	size_t num_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
	size_t page_array_size = ttm_round_pot(num_pages * sizeof(void *));

	if (unlikely(struct_size == 0)) {
		size_t backend_size = ttm_round_pot(vmw_tt_size);

		struct_size = backend_size +
			ttm_round_pot(sizeof(struct vmw_dma_buffer));
		user_struct_size = backend_size +
			ttm_round_pot(sizeof(struct vmw_user_dma_buffer));
	}

	if (dev_priv->map_mode == vmw_dma_alloc_coherent)
		page_array_size +=
			ttm_round_pot(num_pages * sizeof(dma_addr_t));

	return ((user) ? user_struct_size : struct_size) +
		page_array_size;
}

void vmw_dmabuf_bo_free(struct ttm_buffer_object *bo)
{
	struct vmw_dma_buffer *vmw_bo = vmw_dma_buffer(bo);

	vmw_dma_buffer_unmap(vmw_bo);
	kfree(vmw_bo);
}

static void vmw_user_dmabuf_destroy(struct ttm_buffer_object *bo)
{
	struct vmw_user_dma_buffer *vmw_user_bo = vmw_user_dma_buffer(bo);

	vmw_dma_buffer_unmap(&vmw_user_bo->dma);
	ttm_prime_object_kfree(vmw_user_bo, prime);
}

int vmw_dmabuf_init(struct vmw_private *dev_priv,
		    struct vmw_dma_buffer *vmw_bo,
		    size_t size, struct ttm_placement *placement,
		    bool interruptible,
		    void (*bo_free) (struct ttm_buffer_object *bo))
{
	struct ttm_bo_device *bdev = &dev_priv->bdev;
	size_t acc_size;
	int ret;
	bool user = (bo_free == &vmw_user_dmabuf_destroy);

	BUG_ON(!bo_free && (!user && (bo_free != vmw_dmabuf_bo_free)));

	acc_size = vmw_dmabuf_acc_size(dev_priv, size, user);
	memset(vmw_bo, 0, sizeof(*vmw_bo));

	INIT_LIST_HEAD(&vmw_bo->res_list);

	ret = ttm_bo_init(bdev, &vmw_bo->base, size,
			  ttm_bo_type_device, placement,
			  0, interruptible, acc_size,
			  NULL, NULL, bo_free);
	return ret;
}

static void vmw_user_dmabuf_release(struct ttm_base_object **p_base)
{
	struct vmw_user_dma_buffer *vmw_user_bo;
	struct ttm_base_object *base = *p_base;
	struct ttm_buffer_object *bo;

	*p_base = NULL;

	if (unlikely(base == NULL))
		return;

	vmw_user_bo = container_of(base, struct vmw_user_dma_buffer,
				   prime.base);
	bo = &vmw_user_bo->dma.base;
	ttm_bo_unref(&bo);
}

static void vmw_user_dmabuf_ref_obj_release(struct ttm_base_object *base,
					    enum ttm_ref_type ref_type)
{
	struct vmw_user_dma_buffer *user_bo;
	user_bo = container_of(base, struct vmw_user_dma_buffer, prime.base);

	switch (ref_type) {
	case TTM_REF_SYNCCPU_WRITE:
		ttm_bo_synccpu_write_release(&user_bo->dma.base);
		break;
	default:
		BUG();
	}
}

/**
 * vmw_user_dmabuf_alloc - Allocate a user dma buffer
 *
 * @dev_priv: Pointer to a struct device private.
 * @tfile: Pointer to a struct ttm_object_file on which to register the user
 * object.
 * @size: Size of the dma buffer.
 * @shareable: Boolean whether the buffer is shareable with other open files.
 * @handle: Pointer to where the handle value should be assigned.
 * @p_dma_buf: Pointer to where the refcounted struct vmw_dma_buffer pointer
 * should be assigned.
 */
int vmw_user_dmabuf_alloc(struct vmw_private *dev_priv,
			  struct ttm_object_file *tfile,
			  uint32_t size,
			  bool shareable,
			  uint32_t *handle,
			  struct vmw_dma_buffer **p_dma_buf,
			  struct ttm_base_object **p_base)
{
	struct vmw_user_dma_buffer *user_bo;
	struct ttm_buffer_object *tmp;
	int ret;

	user_bo = kzalloc(sizeof(*user_bo), GFP_KERNEL);
	if (unlikely(!user_bo)) {
		DRM_ERROR("Failed to allocate a buffer.\n");
		return -ENOMEM;
	}

	ret = vmw_dmabuf_init(dev_priv, &user_bo->dma, size,
			      (dev_priv->has_mob) ?
			      &vmw_sys_placement :
			      &vmw_vram_sys_placement, true,
			      &vmw_user_dmabuf_destroy);
	if (unlikely(ret != 0))
		return ret;

	tmp = ttm_bo_reference(&user_bo->dma.base);
	ret = ttm_prime_object_init(tfile,
				    size,
				    &user_bo->prime,
				    shareable,
				    ttm_buffer_type,
				    &vmw_user_dmabuf_release,
				    &vmw_user_dmabuf_ref_obj_release);
	if (unlikely(ret != 0)) {
		ttm_bo_unref(&tmp);
		goto out_no_base_object;
	}

	*p_dma_buf = &user_bo->dma;
	if (p_base) {
		*p_base = &user_bo->prime.base;
		kref_get(&(*p_base)->refcount);
	}
	*handle = user_bo->prime.base.hash.key;

out_no_base_object:
	return ret;
}

/**
 * vmw_user_dmabuf_verify_access - verify access permissions on this
 * buffer object.
 *
 * @bo: Pointer to the buffer object being accessed
 * @tfile: Identifying the caller.
 */
int vmw_user_dmabuf_verify_access(struct ttm_buffer_object *bo,
				  struct ttm_object_file *tfile)
{
	struct vmw_user_dma_buffer *vmw_user_bo;

	if (unlikely(bo->destroy != vmw_user_dmabuf_destroy))
		return -EPERM;

	vmw_user_bo = vmw_user_dma_buffer(bo);

	/* Check that the caller has opened the object. */
	if (likely(ttm_ref_object_exists(tfile, &vmw_user_bo->prime.base)))
		return 0;

	DRM_ERROR("Could not grant buffer access.\n");
	return -EPERM;
}

/**
 * vmw_user_dmabuf_synccpu_grab - Grab a struct vmw_user_dma_buffer for cpu
 * access, idling previous GPU operations on the buffer and optionally
 * blocking it for further command submissions.
 *
 * @user_bo: Pointer to the buffer object being grabbed for CPU access
 * @tfile: Identifying the caller.
 * @flags: Flags indicating how the grab should be performed.
 *
 * A blocking grab will be automatically released when @tfile is closed.
 */
static int vmw_user_dmabuf_synccpu_grab(struct vmw_user_dma_buffer *user_bo,
					struct ttm_object_file *tfile,
					uint32_t flags)
{
	struct ttm_buffer_object *bo = &user_bo->dma.base;
	bool existed;
	int ret;

	if (flags & drm_vmw_synccpu_allow_cs) {
		bool nonblock = !!(flags & drm_vmw_synccpu_dontblock);
		long lret;

		lret = reservation_object_wait_timeout_rcu(bo->resv, true, true,
							   nonblock ? 0 : MAX_SCHEDULE_TIMEOUT);
		if (!lret)
			return -EBUSY;
		else if (lret < 0)
			return lret;
		return 0;
	}

	ret = ttm_bo_synccpu_write_grab
		(bo, !!(flags & drm_vmw_synccpu_dontblock));
	if (unlikely(ret != 0))
		return ret;

	ret = ttm_ref_object_add(tfile, &user_bo->prime.base,
				 TTM_REF_SYNCCPU_WRITE, &existed, false);
	if (ret != 0 || existed)
		ttm_bo_synccpu_write_release(&user_bo->dma.base);

	return ret;
}

/**
 * vmw_user_dmabuf_synccpu_release - Release a previous grab for CPU access,
 * and unblock command submission on the buffer if blocked.
 *
 * @handle: Handle identifying the buffer object.
 * @tfile: Identifying the caller.
 * @flags: Flags indicating the type of release.
 */
static int vmw_user_dmabuf_synccpu_release(uint32_t handle,
					   struct ttm_object_file *tfile,
					   uint32_t flags)
{
	if (!(flags & drm_vmw_synccpu_allow_cs))
		return ttm_ref_object_base_unref(tfile, handle,
						 TTM_REF_SYNCCPU_WRITE);

	return 0;
}

/**
 * vmw_user_dmabuf_synccpu_release - ioctl function implementing the synccpu
 * functionality.
 *
 * @dev: Identifies the drm device.
 * @data: Pointer to the ioctl argument.
 * @file_priv: Identifies the caller.
 *
 * This function checks the ioctl arguments for validity and calls the
 * relevant synccpu functions.
 */
int vmw_user_dmabuf_synccpu_ioctl(struct drm_device *dev, void *data,
				  struct drm_file *file_priv)
{
	struct drm_vmw_synccpu_arg *arg =
		(struct drm_vmw_synccpu_arg *) data;
	struct vmw_dma_buffer *dma_buf;
	struct vmw_user_dma_buffer *user_bo;
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	struct ttm_base_object *buffer_base;
	int ret;

	if ((arg->flags & (drm_vmw_synccpu_read | drm_vmw_synccpu_write)) == 0
	    || (arg->flags & ~(drm_vmw_synccpu_read | drm_vmw_synccpu_write |
			       drm_vmw_synccpu_dontblock |
			       drm_vmw_synccpu_allow_cs)) != 0) {
		DRM_ERROR("Illegal synccpu flags.\n");
		return -EINVAL;
	}

	switch (arg->op) {
	case drm_vmw_synccpu_grab:
		ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &dma_buf,
					     &buffer_base);
		if (unlikely(ret != 0))
			return ret;

		user_bo = container_of(dma_buf, struct vmw_user_dma_buffer,
				       dma);
		ret = vmw_user_dmabuf_synccpu_grab(user_bo, tfile, arg->flags);
		vmw_dmabuf_unreference(&dma_buf);
		ttm_base_object_unref(&buffer_base);
		if (unlikely(ret != 0 && ret != -ERESTARTSYS &&
			     ret != -EBUSY)) {
			DRM_ERROR("Failed synccpu grab on handle 0x%08x.\n",
				  (unsigned int) arg->handle);
			return ret;
		}
		break;
	case drm_vmw_synccpu_release:
		ret = vmw_user_dmabuf_synccpu_release(arg->handle, tfile,
						      arg->flags);
		if (unlikely(ret != 0)) {
			DRM_ERROR("Failed synccpu release on handle 0x%08x.\n",
				  (unsigned int) arg->handle);
			return ret;
		}
		break;
	default:
		DRM_ERROR("Invalid synccpu operation.\n");
		return -EINVAL;
	}

	return 0;
}

int vmw_dmabuf_alloc_ioctl(struct drm_device *dev, void *data,
			   struct drm_file *file_priv)
{
	struct vmw_private *dev_priv = vmw_priv(dev);
	union drm_vmw_alloc_dmabuf_arg *arg =
	    (union drm_vmw_alloc_dmabuf_arg *)data;
	struct drm_vmw_alloc_dmabuf_req *req = &arg->req;
	struct drm_vmw_dmabuf_rep *rep = &arg->rep;
	struct vmw_dma_buffer *dma_buf;
	uint32_t handle;
	int ret;

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

	ret = vmw_user_dmabuf_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
				    req->size, false, &handle, &dma_buf,
				    NULL);
	if (unlikely(ret != 0))
		goto out_no_dmabuf;

	rep->handle = handle;
	rep->map_handle = drm_vma_node_offset_addr(&dma_buf->base.vma_node);
	rep->cur_gmr_id = handle;
	rep->cur_gmr_offset = 0;

	vmw_dmabuf_unreference(&dma_buf);

out_no_dmabuf:
	ttm_read_unlock(&dev_priv->reservation_sem);

	return ret;
}

int vmw_dmabuf_unref_ioctl(struct drm_device *dev, void *data,
			   struct drm_file *file_priv)
{
	struct drm_vmw_unref_dmabuf_arg *arg =
	    (struct drm_vmw_unref_dmabuf_arg *)data;

	return ttm_ref_object_base_unref(vmw_fpriv(file_priv)->tfile,
					 arg->handle,
					 TTM_REF_USAGE);
}

int vmw_user_dmabuf_lookup(struct ttm_object_file *tfile,
			   uint32_t handle, struct vmw_dma_buffer **out,
			   struct ttm_base_object **p_base)
{
	struct vmw_user_dma_buffer *vmw_user_bo;
	struct ttm_base_object *base;

	base = ttm_base_object_lookup(tfile, handle);
	if (unlikely(base == NULL)) {
		pr_err("Invalid buffer object handle 0x%08lx\n",
		       (unsigned long)handle);
		return -ESRCH;
	}

	if (unlikely(ttm_base_object_type(base) != ttm_buffer_type)) {
		ttm_base_object_unref(&base);
		pr_err("Invalid buffer object handle 0x%08lx\n",
		       (unsigned long)handle);
		return -EINVAL;
	}

	vmw_user_bo = container_of(base, struct vmw_user_dma_buffer,
				   prime.base);
	(void)ttm_bo_reference(&vmw_user_bo->dma.base);
	if (p_base)
		*p_base = base;
	else
		ttm_base_object_unref(&base);
	*out = &vmw_user_bo->dma;

	return 0;
}

int vmw_user_dmabuf_reference(struct ttm_object_file *tfile,
			      struct vmw_dma_buffer *dma_buf,
			      uint32_t *handle)
{
	struct vmw_user_dma_buffer *user_bo;

	if (dma_buf->base.destroy != vmw_user_dmabuf_destroy)
		return -EINVAL;

	user_bo = container_of(dma_buf, struct vmw_user_dma_buffer, dma);

	*handle = user_bo->prime.base.hash.key;
	return ttm_ref_object_add(tfile, &user_bo->prime.base,
				  TTM_REF_USAGE, NULL, false);
}

/**
 * vmw_dumb_create - Create a dumb kms buffer
 *
 * @file_priv: Pointer to a struct drm_file identifying the caller.
 * @dev: Pointer to the drm device.
 * @args: Pointer to a struct drm_mode_create_dumb structure
 *
 * This is a driver callback for the core drm create_dumb functionality.
 * Note that this is very similar to the vmw_dmabuf_alloc ioctl, except
 * that the arguments have a different format.
 */
int vmw_dumb_create(struct drm_file *file_priv,
		    struct drm_device *dev,
		    struct drm_mode_create_dumb *args)
{
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct vmw_dma_buffer *dma_buf;
	int ret;

	args->pitch = args->width * ((args->bpp + 7) / 8);
	args->size = args->pitch * args->height;

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

	ret = vmw_user_dmabuf_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
				    args->size, false, &args->handle,
				    &dma_buf, NULL);
	if (unlikely(ret != 0))
		goto out_no_dmabuf;

	vmw_dmabuf_unreference(&dma_buf);
out_no_dmabuf:
	ttm_read_unlock(&dev_priv->reservation_sem);
	return ret;
}

/**
 * vmw_dumb_map_offset - Return the address space offset of a dumb buffer
 *
 * @file_priv: Pointer to a struct drm_file identifying the caller.
 * @dev: Pointer to the drm device.
 * @handle: Handle identifying the dumb buffer.
 * @offset: The address space offset returned.
 *
 * This is a driver callback for the core drm dumb_map_offset functionality.
 */
int vmw_dumb_map_offset(struct drm_file *file_priv,
			struct drm_device *dev, uint32_t handle,
			uint64_t *offset)
{
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	struct vmw_dma_buffer *out_buf;
	int ret;

	ret = vmw_user_dmabuf_lookup(tfile, handle, &out_buf, NULL);
	if (ret != 0)
		return -EINVAL;

	*offset = drm_vma_node_offset_addr(&out_buf->base.vma_node);
	vmw_dmabuf_unreference(&out_buf);
	return 0;
}

/**
 * vmw_dumb_destroy - Destroy a dumb boffer
 *
 * @file_priv: Pointer to a struct drm_file identifying the caller.
 * @dev: Pointer to the drm device.
 * @handle: Handle identifying the dumb buffer.
 *
 * This is a driver callback for the core drm dumb_destroy functionality.
 */
int vmw_dumb_destroy(struct drm_file *file_priv,
		     struct drm_device *dev,
		     uint32_t handle)
{
	return ttm_ref_object_base_unref(vmw_fpriv(file_priv)->tfile,
					 handle, TTM_REF_USAGE);
}

/**
 * vmw_resource_buf_alloc - Allocate a backup buffer for a resource.
 *
 * @res:            The resource for which to allocate a backup buffer.
 * @interruptible:  Whether any sleeps during allocation should be
 *                  performed while interruptible.
 */
static int vmw_resource_buf_alloc(struct vmw_resource *res,
				  bool interruptible)
{
	unsigned long size =
		(res->backup_size + PAGE_SIZE - 1) & PAGE_MASK;
	struct vmw_dma_buffer *backup;
	int ret;

	if (likely(res->backup)) {
		BUG_ON(res->backup->base.num_pages * PAGE_SIZE < size);
		return 0;
	}

	backup = kzalloc(sizeof(*backup), GFP_KERNEL);
	if (unlikely(!backup))
		return -ENOMEM;

	ret = vmw_dmabuf_init(res->dev_priv, backup, res->backup_size,
			      res->func->backup_placement,
			      interruptible,
			      &vmw_dmabuf_bo_free);
	if (unlikely(ret != 0))
		goto out_no_dmabuf;

	res->backup = backup;

out_no_dmabuf:
	return ret;
}

/**
 * vmw_resource_do_validate - Make a resource up-to-date and visible
 *                            to the device.
 *
 * @res:            The resource to make visible to the device.
 * @val_buf:        Information about a buffer possibly
 *                  containing backup data if a bind operation is needed.
 *
 * On hardware resource shortage, this function returns -EBUSY and
 * should be retried once resources have been freed up.
 */
static int vmw_resource_do_validate(struct vmw_resource *res,
				    struct ttm_validate_buffer *val_buf)
{
	int ret = 0;
	const struct vmw_res_func *func = res->func;

	if (unlikely(res->id == -1)) {
		ret = func->create(res);
		if (unlikely(ret != 0))
			return ret;
	}

	if (func->bind &&
	    ((func->needs_backup && list_empty(&res->mob_head) &&
	      val_buf->bo != NULL) ||
	     (!func->needs_backup && val_buf->bo != NULL))) {
		ret = func->bind(res, val_buf);
		if (unlikely(ret != 0))
			goto out_bind_failed;
		if (func->needs_backup)
			list_add_tail(&res->mob_head, &res->backup->res_list);
	}

	/*
	 * Only do this on write operations, and move to
	 * vmw_resource_unreserve if it can be called after
	 * backup buffers have been unreserved. Otherwise
	 * sort out locking.
	 */
	res->res_dirty = true;

	return 0;

out_bind_failed:
	func->destroy(res);

	return ret;
}

/**
 * vmw_resource_unreserve - Unreserve a resource previously reserved for
 * command submission.
 *
 * @res:               Pointer to the struct vmw_resource to unreserve.
 * @switch_backup:     Backup buffer has been switched.
 * @new_backup:        Pointer to new backup buffer if command submission
 *                     switched. May be NULL.
 * @new_backup_offset: New backup offset if @switch_backup is true.
 *
 * Currently unreserving a resource means putting it back on the device's
 * resource lru list, so that it can be evicted if necessary.
 */
void vmw_resource_unreserve(struct vmw_resource *res,
			    bool switch_backup,
			    struct vmw_dma_buffer *new_backup,
			    unsigned long new_backup_offset)
{
	struct vmw_private *dev_priv = res->dev_priv;

	if (!list_empty(&res->lru_head))
		return;

	if (switch_backup && new_backup != res->backup) {
		if (res->backup) {
			lockdep_assert_held(&res->backup->base.resv->lock.base);
			list_del_init(&res->mob_head);
			vmw_dmabuf_unreference(&res->backup);
		}

		if (new_backup) {
			res->backup = vmw_dmabuf_reference(new_backup);
			lockdep_assert_held(&new_backup->base.resv->lock.base);
			list_add_tail(&res->mob_head, &new_backup->res_list);
		} else {
			res->backup = NULL;
		}
	}
	if (switch_backup)
		res->backup_offset = new_backup_offset;

	if (!res->func->may_evict || res->id == -1 || res->pin_count)
		return;

	write_lock(&dev_priv->resource_lock);
	list_add_tail(&res->lru_head,
		      &res->dev_priv->res_lru[res->func->res_type]);
	write_unlock(&dev_priv->resource_lock);
}

/**
 * vmw_resource_check_buffer - Check whether a backup buffer is needed
 *                             for a resource and in that case, allocate
 *                             one, reserve and validate it.
 *
 * @res:            The resource for which to allocate a backup buffer.
 * @interruptible:  Whether any sleeps during allocation should be
 *                  performed while interruptible.
 * @val_buf:        On successful return contains data about the
 *                  reserved and validated backup buffer.
 */
static int
vmw_resource_check_buffer(struct vmw_resource *res,
			  bool interruptible,
			  struct ttm_validate_buffer *val_buf)
{
	struct ttm_operation_ctx ctx = { true, false };
	struct list_head val_list;
	bool backup_dirty = false;
	int ret;

	if (unlikely(res->backup == NULL)) {
		ret = vmw_resource_buf_alloc(res, interruptible);
		if (unlikely(ret != 0))
			return ret;
	}

	INIT_LIST_HEAD(&val_list);
	val_buf->bo = ttm_bo_reference(&res->backup->base);
	val_buf->shared = false;
	list_add_tail(&val_buf->head, &val_list);
	ret = ttm_eu_reserve_buffers(NULL, &val_list, interruptible, NULL);
	if (unlikely(ret != 0))
		goto out_no_reserve;

	if (res->func->needs_backup && list_empty(&res->mob_head))
		return 0;

	backup_dirty = res->backup_dirty;
	ret = ttm_bo_validate(&res->backup->base,
			      res->func->backup_placement,
			      &ctx);

	if (unlikely(ret != 0))
		goto out_no_validate;

	return 0;

out_no_validate:
	ttm_eu_backoff_reservation(NULL, &val_list);
out_no_reserve:
	ttm_bo_unref(&val_buf->bo);
	if (backup_dirty)
		vmw_dmabuf_unreference(&res->backup);

	return ret;
}

/**
 * vmw_resource_reserve - Reserve a resource for command submission
 *
 * @res:            The resource to reserve.
 *
 * This function takes the resource off the LRU list and make sure
 * a backup buffer is present for guest-backed resources. However,
 * the buffer may not be bound to the resource at this point.
 *
 */
int vmw_resource_reserve(struct vmw_resource *res, bool interruptible,
			 bool no_backup)
{
	struct vmw_private *dev_priv = res->dev_priv;
	int ret;

	write_lock(&dev_priv->resource_lock);
	list_del_init(&res->lru_head);
	write_unlock(&dev_priv->resource_lock);

	if (res->func->needs_backup && res->backup == NULL &&
	    !no_backup) {
		ret = vmw_resource_buf_alloc(res, interruptible);
		if (unlikely(ret != 0)) {
			DRM_ERROR("Failed to allocate a backup buffer "
				  "of size %lu. bytes\n",
				  (unsigned long) res->backup_size);
			return ret;
		}
	}

	return 0;
}

/**
 * vmw_resource_backoff_reservation - Unreserve and unreference a
 *                                    backup buffer
 *.
 * @val_buf:        Backup buffer information.
 */
static void
vmw_resource_backoff_reservation(struct ttm_validate_buffer *val_buf)
{
	struct list_head val_list;

	if (likely(val_buf->bo == NULL))
		return;

	INIT_LIST_HEAD(&val_list);
	list_add_tail(&val_buf->head, &val_list);
	ttm_eu_backoff_reservation(NULL, &val_list);
	ttm_bo_unref(&val_buf->bo);
}

/**
 * vmw_resource_do_evict - Evict a resource, and transfer its data
 *                         to a backup buffer.
 *
 * @res:            The resource to evict.
 * @interruptible:  Whether to wait interruptible.
 */
static int vmw_resource_do_evict(struct vmw_resource *res, bool interruptible)
{
	struct ttm_validate_buffer val_buf;
	const struct vmw_res_func *func = res->func;
	int ret;

	BUG_ON(!func->may_evict);

	val_buf.bo = NULL;
	val_buf.shared = false;
	ret = vmw_resource_check_buffer(res, interruptible, &val_buf);
	if (unlikely(ret != 0))
		return ret;

	if (unlikely(func->unbind != NULL &&
		     (!func->needs_backup || !list_empty(&res->mob_head)))) {
		ret = func->unbind(res, res->res_dirty, &val_buf);
		if (unlikely(ret != 0))
			goto out_no_unbind;
		list_del_init(&res->mob_head);
	}
	ret = func->destroy(res);
	res->backup_dirty = true;
	res->res_dirty = false;
out_no_unbind:
	vmw_resource_backoff_reservation(&val_buf);

	return ret;
}


/**
 * vmw_resource_validate - Make a resource up-to-date and visible
 *                         to the device.
 *
 * @res:            The resource to make visible to the device.
 *
 * On succesful return, any backup DMA buffer pointed to by @res->backup will
 * be reserved and validated.
 * On hardware resource shortage, this function will repeatedly evict
 * resources of the same type until the validation succeeds.
 */
int vmw_resource_validate(struct vmw_resource *res)
{
	int ret;
	struct vmw_resource *evict_res;
	struct vmw_private *dev_priv = res->dev_priv;
	struct list_head *lru_list = &dev_priv->res_lru[res->func->res_type];
	struct ttm_validate_buffer val_buf;
	unsigned err_count = 0;

	if (!res->func->create)
		return 0;

	val_buf.bo = NULL;
	val_buf.shared = false;
	if (res->backup)
		val_buf.bo = &res->backup->base;
	do {
		ret = vmw_resource_do_validate(res, &val_buf);
		if (likely(ret != -EBUSY))
			break;

		write_lock(&dev_priv->resource_lock);
		if (list_empty(lru_list) || !res->func->may_evict) {
			DRM_ERROR("Out of device device resources "
				  "for %s.\n", res->func->type_name);
			ret = -EBUSY;
			write_unlock(&dev_priv->resource_lock);
			break;
		}

		evict_res = vmw_resource_reference
			(list_first_entry(lru_list, struct vmw_resource,
					  lru_head));
		list_del_init(&evict_res->lru_head);

		write_unlock(&dev_priv->resource_lock);

		ret = vmw_resource_do_evict(evict_res, true);
		if (unlikely(ret != 0)) {
			write_lock(&dev_priv->resource_lock);
			list_add_tail(&evict_res->lru_head, lru_list);
			write_unlock(&dev_priv->resource_lock);
			if (ret == -ERESTARTSYS ||
			    ++err_count > VMW_RES_EVICT_ERR_COUNT) {
				vmw_resource_unreference(&evict_res);
				goto out_no_validate;
			}
		}

		vmw_resource_unreference(&evict_res);
	} while (1);

	if (unlikely(ret != 0))
		goto out_no_validate;
	else if (!res->func->needs_backup && res->backup) {
		list_del_init(&res->mob_head);
		vmw_dmabuf_unreference(&res->backup);
	}

	return 0;

out_no_validate:
	return ret;
}

/**
 * vmw_fence_single_bo - Utility function to fence a single TTM buffer
 *                       object without unreserving it.
 *
 * @bo:             Pointer to the struct ttm_buffer_object to fence.
 * @fence:          Pointer to the fence. If NULL, this function will
 *                  insert a fence into the command stream..
 *
 * Contrary to the ttm_eu version of this function, it takes only
 * a single buffer object instead of a list, and it also doesn't
 * unreserve the buffer object, which needs to be done separately.
 */
void vmw_fence_single_bo(struct ttm_buffer_object *bo,
			 struct vmw_fence_obj *fence)
{
	struct ttm_bo_device *bdev = bo->bdev;

	struct vmw_private *dev_priv =
		container_of(bdev, struct vmw_private, bdev);

	if (fence == NULL) {
		vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
		reservation_object_add_excl_fence(bo->resv, &fence->base);
		dma_fence_put(&fence->base);
	} else
		reservation_object_add_excl_fence(bo->resv, &fence->base);
}

/**
 * vmw_resource_move_notify - TTM move_notify_callback
 *
 * @bo: The TTM buffer object about to move.
 * @mem: The struct ttm_mem_reg indicating to what memory
 *       region the move is taking place.
 *
 * Evicts the Guest Backed hardware resource if the backup
 * buffer is being moved out of MOB memory.
 * Note that this function should not race with the resource
 * validation code as long as it accesses only members of struct
 * resource that remain static while bo::res is !NULL and
 * while we have @bo reserved. struct resource::backup is *not* a
 * static member. The resource validation code will take care
 * to set @bo::res to NULL, while having @bo reserved when the
 * buffer is no longer bound to the resource, so @bo:res can be
 * used to determine whether there is a need to unbind and whether
 * it is safe to unbind.
 */
void vmw_resource_move_notify(struct ttm_buffer_object *bo,
			      struct ttm_mem_reg *mem)
{
	struct vmw_dma_buffer *dma_buf;

	if (mem == NULL)
		return;

	if (bo->destroy != vmw_dmabuf_bo_free &&
	    bo->destroy != vmw_user_dmabuf_destroy)
		return;

	dma_buf = container_of(bo, struct vmw_dma_buffer, base);

	/*
	 * Kill any cached kernel maps before move. An optimization could
	 * be to do this iff source or destination memory type is VRAM.
	 */
	vmw_dma_buffer_unmap(dma_buf);

	if (mem->mem_type != VMW_PL_MOB) {
		struct vmw_resource *res, *n;
		struct ttm_validate_buffer val_buf;

		val_buf.bo = bo;
		val_buf.shared = false;

		list_for_each_entry_safe(res, n, &dma_buf->res_list, mob_head) {

			if (unlikely(res->func->unbind == NULL))
				continue;

			(void) res->func->unbind(res, true, &val_buf);
			res->backup_dirty = true;
			res->res_dirty = false;
			list_del_init(&res->mob_head);
		}

		(void) ttm_bo_wait(bo, false, false);
	}
}


/**
 * vmw_resource_swap_notify - swapout notify callback.
 *
 * @bo: The buffer object to be swapped out.
 */
void vmw_resource_swap_notify(struct ttm_buffer_object *bo)
{
	if (bo->destroy != vmw_dmabuf_bo_free &&
	    bo->destroy != vmw_user_dmabuf_destroy)
		return;

	/* Kill any cached kernel maps before swapout */
	vmw_dma_buffer_unmap(vmw_dma_buffer(bo));
}


/**
 * vmw_query_readback_all - Read back cached query states
 *
 * @dx_query_mob: Buffer containing the DX query MOB
 *
 * Read back cached states from the device if they exist.  This function
 * assumings binding_mutex is held.
 */
int vmw_query_readback_all(struct vmw_dma_buffer *dx_query_mob)
{
	struct vmw_resource *dx_query_ctx;
	struct vmw_private *dev_priv;
	struct {
		SVGA3dCmdHeader header;
		SVGA3dCmdDXReadbackAllQuery body;
	} *cmd;


	/* No query bound, so do nothing */
	if (!dx_query_mob || !dx_query_mob->dx_query_ctx)
		return 0;

	dx_query_ctx = dx_query_mob->dx_query_ctx;
	dev_priv     = dx_query_ctx->dev_priv;

	cmd = vmw_fifo_reserve_dx(dev_priv, sizeof(*cmd), dx_query_ctx->id);
	if (unlikely(cmd == NULL)) {
		DRM_ERROR("Failed reserving FIFO space for "
			  "query MOB read back.\n");
		return -ENOMEM;
	}

	cmd->header.id   = SVGA_3D_CMD_DX_READBACK_ALL_QUERY;
	cmd->header.size = sizeof(cmd->body);
	cmd->body.cid    = dx_query_ctx->id;

	vmw_fifo_commit(dev_priv, sizeof(*cmd));

	/* Triggers a rebind the next time affected context is bound */
	dx_query_mob->dx_query_ctx = NULL;

	return 0;
}


/**
 * vmw_query_move_notify - Read back cached query states
 *
 * @bo: The TTM buffer object about to move.
 * @mem: The memory region @bo is moving to.
 *
 * Called before the query MOB is swapped out to read back cached query
 * states from the device.
 */
void vmw_query_move_notify(struct ttm_buffer_object *bo,
			   struct ttm_mem_reg *mem)
{
	struct vmw_dma_buffer *dx_query_mob;
	struct ttm_bo_device *bdev = bo->bdev;
	struct vmw_private *dev_priv;


	dev_priv = container_of(bdev, struct vmw_private, bdev);

	mutex_lock(&dev_priv->binding_mutex);

	dx_query_mob = container_of(bo, struct vmw_dma_buffer, base);
	if (mem == NULL || !dx_query_mob || !dx_query_mob->dx_query_ctx) {
		mutex_unlock(&dev_priv->binding_mutex);
		return;
	}

	/* If BO is being moved from MOB to system memory */
	if (mem->mem_type == TTM_PL_SYSTEM && bo->mem.mem_type == VMW_PL_MOB) {
		struct vmw_fence_obj *fence;

		(void) vmw_query_readback_all(dx_query_mob);
		mutex_unlock(&dev_priv->binding_mutex);

		/* Create a fence and attach the BO to it */
		(void) vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
		vmw_fence_single_bo(bo, fence);

		if (fence != NULL)
			vmw_fence_obj_unreference(&fence);

		(void) ttm_bo_wait(bo, false, false);
	} else
		mutex_unlock(&dev_priv->binding_mutex);

}

/**
 * vmw_resource_needs_backup - Return whether a resource needs a backup buffer.
 *
 * @res:            The resource being queried.
 */
bool vmw_resource_needs_backup(const struct vmw_resource *res)
{
	return res->func->needs_backup;
}

/**
 * vmw_resource_evict_type - Evict all resources of a specific type
 *
 * @dev_priv:       Pointer to a device private struct
 * @type:           The resource type to evict
 *
 * To avoid thrashing starvation or as part of the hibernation sequence,
 * try to evict all evictable resources of a specific type.
 */
static void vmw_resource_evict_type(struct vmw_private *dev_priv,
				    enum vmw_res_type type)
{
	struct list_head *lru_list = &dev_priv->res_lru[type];
	struct vmw_resource *evict_res;
	unsigned err_count = 0;
	int ret;

	do {
		write_lock(&dev_priv->resource_lock);

		if (list_empty(lru_list))
			goto out_unlock;

		evict_res = vmw_resource_reference(
			list_first_entry(lru_list, struct vmw_resource,
					 lru_head));
		list_del_init(&evict_res->lru_head);
		write_unlock(&dev_priv->resource_lock);

		ret = vmw_resource_do_evict(evict_res, false);
		if (unlikely(ret != 0)) {
			write_lock(&dev_priv->resource_lock);
			list_add_tail(&evict_res->lru_head, lru_list);
			write_unlock(&dev_priv->resource_lock);
			if (++err_count > VMW_RES_EVICT_ERR_COUNT) {
				vmw_resource_unreference(&evict_res);
				return;
			}
		}

		vmw_resource_unreference(&evict_res);
	} while (1);

out_unlock:
	write_unlock(&dev_priv->resource_lock);
}

/**
 * vmw_resource_evict_all - Evict all evictable resources
 *
 * @dev_priv:       Pointer to a device private struct
 *
 * To avoid thrashing starvation or as part of the hibernation sequence,
 * evict all evictable resources. In particular this means that all
 * guest-backed resources that are registered with the device are
 * evicted and the OTable becomes clean.
 */
void vmw_resource_evict_all(struct vmw_private *dev_priv)
{
	enum vmw_res_type type;

	mutex_lock(&dev_priv->cmdbuf_mutex);

	for (type = 0; type < vmw_res_max; ++type)
		vmw_resource_evict_type(dev_priv, type);

	mutex_unlock(&dev_priv->cmdbuf_mutex);
}

/**
 * vmw_resource_pin - Add a pin reference on a resource
 *
 * @res: The resource to add a pin reference on
 *
 * This function adds a pin reference, and if needed validates the resource.
 * Having a pin reference means that the resource can never be evicted, and
 * its id will never change as long as there is a pin reference.
 * This function returns 0 on success and a negative error code on failure.
 */
int vmw_resource_pin(struct vmw_resource *res, bool interruptible)
{
	struct ttm_operation_ctx ctx = { interruptible, false };
	struct vmw_private *dev_priv = res->dev_priv;
	int ret;

	ttm_write_lock(&dev_priv->reservation_sem, interruptible);
	mutex_lock(&dev_priv->cmdbuf_mutex);
	ret = vmw_resource_reserve(res, interruptible, false);
	if (ret)
		goto out_no_reserve;

	if (res->pin_count == 0) {
		struct vmw_dma_buffer *vbo = NULL;

		if (res->backup) {
			vbo = res->backup;

			ttm_bo_reserve(&vbo->base, interruptible, false, NULL);
			if (!vbo->pin_count) {
				ret = ttm_bo_validate
					(&vbo->base,
					 res->func->backup_placement,
					 &ctx);
				if (ret) {
					ttm_bo_unreserve(&vbo->base);
					goto out_no_validate;
				}
			}

			/* Do we really need to pin the MOB as well? */
			vmw_bo_pin_reserved(vbo, true);
		}
		ret = vmw_resource_validate(res);
		if (vbo)
			ttm_bo_unreserve(&vbo->base);
		if (ret)
			goto out_no_validate;
	}
	res->pin_count++;

out_no_validate:
	vmw_resource_unreserve(res, false, NULL, 0UL);
out_no_reserve:
	mutex_unlock(&dev_priv->cmdbuf_mutex);
	ttm_write_unlock(&dev_priv->reservation_sem);

	return ret;
}

/**
 * vmw_resource_unpin - Remove a pin reference from a resource
 *
 * @res: The resource to remove a pin reference from
 *
 * Having a pin reference means that the resource can never be evicted, and
 * its id will never change as long as there is a pin reference.
 */
void vmw_resource_unpin(struct vmw_resource *res)
{
	struct vmw_private *dev_priv = res->dev_priv;
	int ret;

	(void) ttm_read_lock(&dev_priv->reservation_sem, false);
	mutex_lock(&dev_priv->cmdbuf_mutex);

	ret = vmw_resource_reserve(res, false, true);
	WARN_ON(ret);

	WARN_ON(res->pin_count == 0);
	if (--res->pin_count == 0 && res->backup) {
		struct vmw_dma_buffer *vbo = res->backup;

		(void) ttm_bo_reserve(&vbo->base, false, false, NULL);
		vmw_bo_pin_reserved(vbo, false);
		ttm_bo_unreserve(&vbo->base);
	}

	vmw_resource_unreserve(res, false, NULL, 0UL);

	mutex_unlock(&dev_priv->cmdbuf_mutex);
	ttm_read_unlock(&dev_priv->reservation_sem);
}

/**
 * vmw_res_type - Return the resource type
 *
 * @res: Pointer to the resource
 */
enum vmw_res_type vmw_res_type(const struct vmw_resource *res)
{
	return res->func->res_type;
}