// SPDX-License-Identifier: GPL-2.0 OR MIT
/**************************************************************************
 *
 * Copyright 2009-2015 VMware, Inc., Palo Alto, CA., USA
 *
 * 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_placement.h>
#include <drm/drmP.h>
#include "vmwgfx_resource_priv.h"
#include "vmwgfx_binding.h"

#define VMW_RES_EVICT_ERR_COUNT 10

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_bo_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 bo.
 *
 * 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_buffer_object **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_bo_lookup(tfile, handle, out_buf, NULL);
        return ret;
}

/**
 * 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_buffer_object *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_bo_init(res->dev_priv, backup, res->backup_size,
                              res->func->backup_placement,
                              interruptible,
                              &vmw_bo_bo_free);
        if (unlikely(ret != 0))
                goto out_no_bo;

        res->backup = backup;

out_no_bo:
        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_buffer_object *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_bo_unreference(&res->backup);
                }

                if (new_backup) {
                        res->backup = vmw_bo_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.
 *
 * @ticket:         The ww aqcquire context to use, or NULL if trylocking.
 * @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 ww_acquire_ctx *ticket,
                          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(ticket, &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(ticket, &val_list);
out_no_reserve:
        ttm_bo_unref(&val_buf->bo);
        if (backup_dirty)
                vmw_bo_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
 *.
 * @ticket:         The ww acquire ctx used for reservation.
 * @val_buf:        Backup buffer information.
 */
static void
vmw_resource_backoff_reservation(struct ww_acquire_ctx *ticket,
                                 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(ticket, &val_list);
        ttm_bo_unref(&val_buf->bo);
}

/**
 * vmw_resource_do_evict - Evict a resource, and transfer its data
 *                         to a backup buffer.
 *
 * @ticket:         The ww acquire ticket to use, or NULL if trylocking.
 * @res:            The resource to evict.
 * @interruptible:  Whether to wait interruptible.
 */
static int vmw_resource_do_evict(struct ww_acquire_ctx *ticket,
                                 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(ticket, 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(ticket, &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);

                /* Trylock backup buffers with a NULL ticket. */
                ret = vmw_resource_do_evict(NULL, 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_bo_unreference(&res->backup);
        }

        return 0;

out_no_validate:
        return ret;
}


/**
 * vmw_resource_unbind_list
 *
 * @vbo: Pointer to the current backing MOB.
 *
 * Evicts the Guest Backed hardware resource if the backup
 * buffer is being moved out of MOB memory.
 * Note that this function will not race with the resource
 * validation code, since resource validation and eviction
 * both require the backup buffer to be reserved.
 */
void vmw_resource_unbind_list(struct vmw_buffer_object *vbo)
{

        struct vmw_resource *res, *next;
        struct ttm_validate_buffer val_buf = {
                .bo = &vbo->base,
                .shared = false
        };

        lockdep_assert_held(&vbo->base.resv->lock.base);
        list_for_each_entry_safe(res, next, &vbo->res_list, mob_head) {
                if (!res->func->unbind)
                        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(&vbo->base, false, false);
}


/**
 * 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_buffer_object *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_buffer_object *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_buffer_object, 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_bo_fence_single(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;
        struct ww_acquire_ctx ticket;

        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);

                /* Wait lock backup buffers with a ticket. */
                ret = vmw_resource_do_evict(&ticket, 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_buffer_object *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_buffer_object *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;
}