Merge branch 'nfsd-next' of git://linux-nfs.org/~bfields/linux

[~andy/linux] / drivers / gpu / drm / vmwgfx / vmwgfx_resource.c

/**************************************************************************
 *
 * Copyright © 2009 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"

#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;
};

struct vmw_stream {
        struct vmw_resource res;
        uint32_t stream_id;
};

struct vmw_user_stream {
        struct ttm_base_object base;
        struct vmw_stream stream;
};


static uint64_t vmw_user_stream_size;

static const struct vmw_res_func vmw_stream_func = {
        .res_type = vmw_res_stream,
        .needs_backup = false,
        .may_evict = false,
        .type_name = "video streams",
        .backup_placement = NULL,
        .create = NULL,
        .destroy = NULL,
        .bind = NULL,
        .unbind = NULL
};

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];

        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, false, 0);
                if (!list_empty(&res->mob_head) &&
                    res->func->unbind != NULL) {
                        struct ttm_validate_buffer val_buf;

                        val_buf.bo = bo;
                        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)) {
                res->hw_destroy(res);
                mutex_lock(&dev_priv->binding_mutex);
                vmw_context_binding_res_list_kill(&res->binding_head);
                mutex_unlock(&dev_priv->binding_mutex);
        }

        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);
}

void vmw_resource_unreference(struct vmw_resource **p_res)
{
        struct vmw_resource *res = *p_res;
        struct vmw_private *dev_priv = res->dev_priv;

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


/**
 * 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);
}

struct vmw_resource *vmw_resource_lookup(struct vmw_private *dev_priv,
                                         struct idr *idr, int id)
{
        struct vmw_resource *res;

        read_lock(&dev_priv->resource_lock);
        res = idr_find(idr, id);
        if (res && res->avail)
                kref_get(&res->kref);
        else
                res = NULL;
        read_unlock(&dev_priv->resource_lock);

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

        return res;
}

/**
 * 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);
        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);

        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);

        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,
                          NULL, acc_size, 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 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 == NULL)) {
                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;
        *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);
        return (vmw_user_bo->prime.base.tfile == tfile ||
                vmw_user_bo->prime.base.shareable) ? 0 : -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) {
                struct ttm_bo_device *bdev = bo->bdev;

                spin_lock(&bdev->fence_lock);
                ret = ttm_bo_wait(bo, false, true,
                                  !!(flags & drm_vmw_synccpu_dontblock));
                spin_unlock(&bdev->fence_lock);
                return ret;
        }

        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);
        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;
        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);
                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);
                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;
        struct vmw_master *vmaster = vmw_master(file_priv->master);
        int ret;

        ret = ttm_read_lock(&vmaster->lock, 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);
        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(&vmaster->lock);

        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 vmw_user_dma_buffer *vmw_user_bo;
        struct ttm_base_object *base;

        base = ttm_base_object_lookup(tfile, handle);
        if (unlikely(base == NULL)) {
                printk(KERN_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);
                printk(KERN_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);
        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);
}

/*
 * Stream management
 */

static void vmw_stream_destroy(struct vmw_resource *res)
{
        struct vmw_private *dev_priv = res->dev_priv;
        struct vmw_stream *stream;
        int ret;

        DRM_INFO("%s: unref\n", __func__);
        stream = container_of(res, struct vmw_stream, res);

        ret = vmw_overlay_unref(dev_priv, stream->stream_id);
        WARN_ON(ret != 0);
}

static int vmw_stream_init(struct vmw_private *dev_priv,
                           struct vmw_stream *stream,
                           void (*res_free) (struct vmw_resource *res))
{
        struct vmw_resource *res = &stream->res;
        int ret;

        ret = vmw_resource_init(dev_priv, res, false, res_free,
                                &vmw_stream_func);

        if (unlikely(ret != 0)) {
                if (res_free == NULL)
                        kfree(stream);
                else
                        res_free(&stream->res);
                return ret;
        }

        ret = vmw_overlay_claim(dev_priv, &stream->stream_id);
        if (ret) {
                vmw_resource_unreference(&res);
                return ret;
        }

        DRM_INFO("%s: claimed\n", __func__);

        vmw_resource_activate(&stream->res, vmw_stream_destroy);
        return 0;
}

static void vmw_user_stream_free(struct vmw_resource *res)
{
        struct vmw_user_stream *stream =
            container_of(res, struct vmw_user_stream, stream.res);
        struct vmw_private *dev_priv = res->dev_priv;

        ttm_base_object_kfree(stream, base);
        ttm_mem_global_free(vmw_mem_glob(dev_priv),
                            vmw_user_stream_size);
}

/**
 * This function is called when user space has no more references on the
 * base object. It releases the base-object's reference on the resource object.
 */

static void vmw_user_stream_base_release(struct ttm_base_object **p_base)
{
        struct ttm_base_object *base = *p_base;
        struct vmw_user_stream *stream =
            container_of(base, struct vmw_user_stream, base);
        struct vmw_resource *res = &stream->stream.res;

        *p_base = NULL;
        vmw_resource_unreference(&res);
}

int vmw_stream_unref_ioctl(struct drm_device *dev, void *data,
                           struct drm_file *file_priv)
{
        struct vmw_private *dev_priv = vmw_priv(dev);
        struct vmw_resource *res;
        struct vmw_user_stream *stream;
        struct drm_vmw_stream_arg *arg = (struct drm_vmw_stream_arg *)data;
        struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
        struct idr *idr = &dev_priv->res_idr[vmw_res_stream];
        int ret = 0;


        res = vmw_resource_lookup(dev_priv, idr, arg->stream_id);
        if (unlikely(res == NULL))
                return -EINVAL;

        if (res->res_free != &vmw_user_stream_free) {
                ret = -EINVAL;
                goto out;
        }

        stream = container_of(res, struct vmw_user_stream, stream.res);
        if (stream->base.tfile != tfile) {
                ret = -EINVAL;
                goto out;
        }

        ttm_ref_object_base_unref(tfile, stream->base.hash.key, TTM_REF_USAGE);
out:
        vmw_resource_unreference(&res);
        return ret;
}

int vmw_stream_claim_ioctl(struct drm_device *dev, void *data,
                           struct drm_file *file_priv)
{
        struct vmw_private *dev_priv = vmw_priv(dev);
        struct vmw_user_stream *stream;
        struct vmw_resource *res;
        struct vmw_resource *tmp;
        struct drm_vmw_stream_arg *arg = (struct drm_vmw_stream_arg *)data;
        struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
        struct vmw_master *vmaster = vmw_master(file_priv->master);
        int ret;

        /*
         * Approximate idr memory usage with 128 bytes. It will be limited
         * by maximum number_of streams anyway?
         */

        if (unlikely(vmw_user_stream_size == 0))
                vmw_user_stream_size = ttm_round_pot(sizeof(*stream)) + 128;

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

        ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv),
                                   vmw_user_stream_size,
                                   false, true);
        if (unlikely(ret != 0)) {
                if (ret != -ERESTARTSYS)
                        DRM_ERROR("Out of graphics memory for stream"
                                  " creation.\n");
                goto out_unlock;
        }


        stream = kmalloc(sizeof(*stream), GFP_KERNEL);
        if (unlikely(stream == NULL)) {
                ttm_mem_global_free(vmw_mem_glob(dev_priv),
                                    vmw_user_stream_size);
                ret = -ENOMEM;
                goto out_unlock;
        }

        res = &stream->stream.res;
        stream->base.shareable = false;
        stream->base.tfile = NULL;

        /*
         * From here on, the destructor takes over resource freeing.
         */

        ret = vmw_stream_init(dev_priv, &stream->stream, vmw_user_stream_free);
        if (unlikely(ret != 0))
                goto out_unlock;

        tmp = vmw_resource_reference(res);
        ret = ttm_base_object_init(tfile, &stream->base, false, VMW_RES_STREAM,
                                   &vmw_user_stream_base_release, NULL);

        if (unlikely(ret != 0)) {
                vmw_resource_unreference(&tmp);
                goto out_err;
        }

        arg->stream_id = res->id;
out_err:
        vmw_resource_unreference(&res);
out_unlock:
        ttm_read_unlock(&vmaster->lock);
        return ret;
}

int vmw_user_stream_lookup(struct vmw_private *dev_priv,
                           struct ttm_object_file *tfile,
                           uint32_t *inout_id, struct vmw_resource **out)
{
        struct vmw_user_stream *stream;
        struct vmw_resource *res;
        int ret;

        res = vmw_resource_lookup(dev_priv, &dev_priv->res_idr[vmw_res_stream],
                                  *inout_id);
        if (unlikely(res == NULL))
                return -EINVAL;

        if (res->res_free != &vmw_user_stream_free) {
                ret = -EINVAL;
                goto err_ref;
        }

        stream = container_of(res, struct vmw_user_stream, stream.res);
        if (stream->base.tfile != tfile) {
                ret = -EPERM;
                goto err_ref;
        }

        *inout_id = stream->stream.stream_id;
        *out = res;
        return 0;
err_ref:
        vmw_resource_unreference(&res);
        return ret;
}


/**
 * 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_master *vmaster = vmw_master(file_priv->master);
        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(&vmaster->lock, 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);
        if (unlikely(ret != 0))
                goto out_no_dmabuf;

        vmw_dmabuf_unreference(&dma_buf);
out_no_dmabuf:
        ttm_read_unlock(&vmaster->lock);
        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);
        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 == NULL))
                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.
 * @new_backup:        Pointer to new backup buffer if command submission
 *                     switched.
 * @new_backup_offset: New backup offset if @new_backup is !NULL.
 *
 * 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,
                            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 (new_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);
                }

                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);
        }
        if (new_backup)
                res->backup_offset = new_backup_offset;

        if (!res->func->may_evict || res->id == -1)
                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 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);
        list_add_tail(&val_buf->head, &val_list);
        ret = ttm_eu_reserve_buffers(NULL, &val_list);
        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,
                              true, false);

        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 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, true);
                if (unlikely(ret != 0))
                        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.
 */
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;
        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 (likely(!res->func->may_evict))
                return 0;

        val_buf.bo = NULL;
        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 ttm_bo_driver *driver = bdev->driver;
        struct vmw_fence_obj *old_fence_obj;
        struct vmw_private *dev_priv =
                container_of(bdev, struct vmw_private, bdev);

        if (fence == NULL)
                vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
        else
                driver->sync_obj_ref(fence);

        spin_lock(&bdev->fence_lock);

        old_fence_obj = bo->sync_obj;
        bo->sync_obj = fence;

        spin_unlock(&bdev->fence_lock);

        if (old_fence_obj)
                vmw_fence_obj_unreference(&old_fence_obj);
}

/**
 * vmw_resource_move_notify - TTM move_notify_callback
 *
 * @bo:             The TTM buffer object about to move.
 * @mem:            The truct 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);

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

                val_buf.bo = bo;

                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);
                }

                spin_lock(&bdev->fence_lock);
                (void) ttm_bo_wait(bo, false, false, false);
                spin_unlock(&bdev->fence_lock);
        }
}

/**
 * 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);
}