/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/**************************************************************************
 *
 * Copyright (c) 2006-2009 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.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#define pr_fmt(fmt) "[TTM] " fmt

#include <drm/ttm/ttm_module.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
#include <linux/jiffies.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/atomic.h>
#include <linux/dma-resv.h>

static void ttm_bo_global_kobj_release(struct kobject *kobj);

/**
 * ttm_global_mutex - protecting the global BO state
 */
DEFINE_MUTEX(ttm_global_mutex);
unsigned ttm_bo_glob_use_count;
struct ttm_bo_global ttm_bo_glob;

static struct attribute ttm_bo_count = {
        .name = "bo_count",
        .mode = S_IRUGO
};

/* default destructor */
static void ttm_bo_default_destroy(struct ttm_buffer_object *bo)
{
        kfree(bo);
}

static inline int ttm_mem_type_from_place(const struct ttm_place *place,
                                          uint32_t *mem_type)
{
        int pos;

        pos = ffs(place->flags & TTM_PL_MASK_MEM);
        if (unlikely(!pos))
                return -EINVAL;

        *mem_type = pos - 1;
        return 0;
}

static void ttm_mem_type_debug(struct ttm_bo_device *bdev, struct drm_printer *p,
                               int mem_type)
{
        struct ttm_mem_type_manager *man = &bdev->man[mem_type];

        drm_printf(p, "    has_type: %d\n", man->has_type);
        drm_printf(p, "    use_type: %d\n", man->use_type);
        drm_printf(p, "    flags: 0x%08X\n", man->flags);
        drm_printf(p, "    gpu_offset: 0x%08llX\n", man->gpu_offset);
        drm_printf(p, "    size: %llu\n", man->size);
        drm_printf(p, "    available_caching: 0x%08X\n", man->available_caching);
        drm_printf(p, "    default_caching: 0x%08X\n", man->default_caching);
        if (mem_type != TTM_PL_SYSTEM)
                (*man->func->debug)(man, p);
}

static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
                                        struct ttm_placement *placement)
{
        struct drm_printer p = drm_debug_printer(TTM_PFX);
        int i, ret, mem_type;

        drm_printf(&p, "No space for %p (%lu pages, %luK, %luM)\n",
                   bo, bo->mem.num_pages, bo->mem.size >> 10,
                   bo->mem.size >> 20);
        for (i = 0; i < placement->num_placement; i++) {
                ret = ttm_mem_type_from_place(&placement->placement[i],
                                                &mem_type);
                if (ret)
                        return;
                drm_printf(&p, "  placement[%d]=0x%08X (%d)\n",
                           i, placement->placement[i].flags, mem_type);
                ttm_mem_type_debug(bo->bdev, &p, mem_type);
        }
}

static ssize_t ttm_bo_global_show(struct kobject *kobj,
                                  struct attribute *attr,
                                  char *buffer)
{
        struct ttm_bo_global *glob =
                container_of(kobj, struct ttm_bo_global, kobj);

        return snprintf(buffer, PAGE_SIZE, "%d\n",
                                atomic_read(&glob->bo_count));
}

static struct attribute *ttm_bo_global_attrs[] = {
        &ttm_bo_count,
        NULL
};

static const struct sysfs_ops ttm_bo_global_ops = {
        .show = &ttm_bo_global_show
};

static struct kobj_type ttm_bo_glob_kobj_type  = {
        .release = &ttm_bo_global_kobj_release,
        .sysfs_ops = &ttm_bo_global_ops,
        .default_attrs = ttm_bo_global_attrs
};


static inline uint32_t ttm_bo_type_flags(unsigned type)
{
        return 1 << (type);
}

static void ttm_bo_release_list(struct kref *list_kref)
{
        struct ttm_buffer_object *bo =
            container_of(list_kref, struct ttm_buffer_object, list_kref);
        struct ttm_bo_device *bdev = bo->bdev;
        size_t acc_size = bo->acc_size;

        BUG_ON(kref_read(&bo->list_kref));
        BUG_ON(kref_read(&bo->kref));
        BUG_ON(atomic_read(&bo->cpu_writers));
        BUG_ON(bo->mem.mm_node != NULL);
        BUG_ON(!list_empty(&bo->lru));
        BUG_ON(!list_empty(&bo->ddestroy));
        ttm_tt_destroy(bo->ttm);
        atomic_dec(&bo->bdev->glob->bo_count);
        dma_fence_put(bo->moving);
        if (!ttm_bo_uses_embedded_gem_object(bo))
                dma_resv_fini(&bo->base._resv);
        mutex_destroy(&bo->wu_mutex);
        bo->destroy(bo);
        ttm_mem_global_free(bdev->glob->mem_glob, acc_size);
}

static void ttm_bo_add_mem_to_lru(struct ttm_buffer_object *bo,
                                  struct ttm_mem_reg *mem)
{
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_type_manager *man;

        dma_resv_assert_held(bo->base.resv);

        if (!list_empty(&bo->lru))
                return;

        if (mem->placement & TTM_PL_FLAG_NO_EVICT)
                return;

        man = &bdev->man[mem->mem_type];
        list_add_tail(&bo->lru, &man->lru[bo->priority]);
        kref_get(&bo->list_kref);

        if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED) && bo->ttm &&
            !(bo->ttm->page_flags & (TTM_PAGE_FLAG_SG |
                                     TTM_PAGE_FLAG_SWAPPED))) {
                list_add_tail(&bo->swap, &bdev->glob->swap_lru[bo->priority]);
                kref_get(&bo->list_kref);
        }
}

void ttm_bo_add_to_lru(struct ttm_buffer_object *bo)
{
        ttm_bo_add_mem_to_lru(bo, &bo->mem);
}
EXPORT_SYMBOL(ttm_bo_add_to_lru);

static void ttm_bo_ref_bug(struct kref *list_kref)
{
        BUG();
}

void ttm_bo_del_from_lru(struct ttm_buffer_object *bo)
{
        struct ttm_bo_device *bdev = bo->bdev;
        bool notify = false;

        if (!list_empty(&bo->swap)) {
                list_del_init(&bo->swap);
                kref_put(&bo->list_kref, ttm_bo_ref_bug);
                notify = true;
        }
        if (!list_empty(&bo->lru)) {
                list_del_init(&bo->lru);
                kref_put(&bo->list_kref, ttm_bo_ref_bug);
                notify = true;
        }

        if (notify && bdev->driver->del_from_lru_notify)
                bdev->driver->del_from_lru_notify(bo);
}

void ttm_bo_del_sub_from_lru(struct ttm_buffer_object *bo)
{
        struct ttm_bo_global *glob = bo->bdev->glob;

        spin_lock(&glob->lru_lock);
        ttm_bo_del_from_lru(bo);
        spin_unlock(&glob->lru_lock);
}
EXPORT_SYMBOL(ttm_bo_del_sub_from_lru);

static void ttm_bo_bulk_move_set_pos(struct ttm_lru_bulk_move_pos *pos,
                                     struct ttm_buffer_object *bo)
{
        if (!pos->first)
                pos->first = bo;
        pos->last = bo;
}

void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
                             struct ttm_lru_bulk_move *bulk)
{
        dma_resv_assert_held(bo->base.resv);

        ttm_bo_del_from_lru(bo);
        ttm_bo_add_to_lru(bo);

        if (bulk && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
                switch (bo->mem.mem_type) {
                case TTM_PL_TT:
                        ttm_bo_bulk_move_set_pos(&bulk->tt[bo->priority], bo);
                        break;

                case TTM_PL_VRAM:
                        ttm_bo_bulk_move_set_pos(&bulk->vram[bo->priority], bo);
                        break;
                }
                if (bo->ttm && !(bo->ttm->page_flags &
                                 (TTM_PAGE_FLAG_SG | TTM_PAGE_FLAG_SWAPPED)))
                        ttm_bo_bulk_move_set_pos(&bulk->swap[bo->priority], bo);
        }
}
EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);

void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
{
        unsigned i;

        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
                struct ttm_mem_type_manager *man;

                if (!pos->first)
                        continue;

                dma_resv_assert_held(pos->first->base.resv);
                dma_resv_assert_held(pos->last->base.resv);

                man = &pos->first->bdev->man[TTM_PL_TT];
                list_bulk_move_tail(&man->lru[i], &pos->first->lru,
                                    &pos->last->lru);
        }

        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
                struct ttm_mem_type_manager *man;

                if (!pos->first)
                        continue;

                dma_resv_assert_held(pos->first->base.resv);
                dma_resv_assert_held(pos->last->base.resv);

                man = &pos->first->bdev->man[TTM_PL_VRAM];
                list_bulk_move_tail(&man->lru[i], &pos->first->lru,
                                    &pos->last->lru);
        }

        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                struct ttm_lru_bulk_move_pos *pos = &bulk->swap[i];
                struct list_head *lru;

                if (!pos->first)
                        continue;

                dma_resv_assert_held(pos->first->base.resv);
                dma_resv_assert_held(pos->last->base.resv);

                lru = &pos->first->bdev->glob->swap_lru[i];
                list_bulk_move_tail(lru, &pos->first->swap, &pos->last->swap);
        }
}
EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);

static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
                                  struct ttm_mem_reg *mem, bool evict,
                                  struct ttm_operation_ctx *ctx)
{
        struct ttm_bo_device *bdev = bo->bdev;
        bool old_is_pci = ttm_mem_reg_is_pci(bdev, &bo->mem);
        bool new_is_pci = ttm_mem_reg_is_pci(bdev, mem);
        struct ttm_mem_type_manager *old_man = &bdev->man[bo->mem.mem_type];
        struct ttm_mem_type_manager *new_man = &bdev->man[mem->mem_type];
        int ret = 0;

        if (old_is_pci || new_is_pci ||
            ((mem->placement & bo->mem.placement & TTM_PL_MASK_CACHING) == 0)) {
                ret = ttm_mem_io_lock(old_man, true);
                if (unlikely(ret != 0))
                        goto out_err;
                ttm_bo_unmap_virtual_locked(bo);
                ttm_mem_io_unlock(old_man);
        }

        /*
         * Create and bind a ttm if required.
         */

        if (!(new_man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
                if (bo->ttm == NULL) {
                        bool zero = !(old_man->flags & TTM_MEMTYPE_FLAG_FIXED);
                        ret = ttm_tt_create(bo, zero);
                        if (ret)
                                goto out_err;
                }

                ret = ttm_tt_set_placement_caching(bo->ttm, mem->placement);
                if (ret)
                        goto out_err;

                if (mem->mem_type != TTM_PL_SYSTEM) {
                        ret = ttm_tt_bind(bo->ttm, mem, ctx);
                        if (ret)
                                goto out_err;
                }

                if (bo->mem.mem_type == TTM_PL_SYSTEM) {
                        if (bdev->driver->move_notify)
                                bdev->driver->move_notify(bo, evict, mem);
                        bo->mem = *mem;
                        mem->mm_node = NULL;
                        goto moved;
                }
        }

        if (bdev->driver->move_notify)
                bdev->driver->move_notify(bo, evict, mem);

        if (!(old_man->flags & TTM_MEMTYPE_FLAG_FIXED) &&
            !(new_man->flags & TTM_MEMTYPE_FLAG_FIXED))
                ret = ttm_bo_move_ttm(bo, ctx, mem);
        else if (bdev->driver->move)
                ret = bdev->driver->move(bo, evict, ctx, mem);
        else
                ret = ttm_bo_move_memcpy(bo, ctx, mem);

        if (ret) {
                if (bdev->driver->move_notify) {
                        swap(*mem, bo->mem);
                        bdev->driver->move_notify(bo, false, mem);
                        swap(*mem, bo->mem);
                }

                goto out_err;
        }

moved:
        if (bo->evicted) {
                if (bdev->driver->invalidate_caches) {
                        ret = bdev->driver->invalidate_caches(bdev, bo->mem.placement);
                        if (ret)
                                pr_err("Can not flush read caches\n");
                }
                bo->evicted = false;
        }

        if (bo->mem.mm_node)
                bo->offset = (bo->mem.start << PAGE_SHIFT) +
                    bdev->man[bo->mem.mem_type].gpu_offset;
        else
                bo->offset = 0;

        ctx->bytes_moved += bo->num_pages << PAGE_SHIFT;
        return 0;

out_err:
        new_man = &bdev->man[bo->mem.mem_type];
        if (new_man->flags & TTM_MEMTYPE_FLAG_FIXED) {
                ttm_tt_destroy(bo->ttm);
                bo->ttm = NULL;
        }

        return ret;
}

/**
 * Call bo::reserved.
 * Will release GPU memory type usage on destruction.
 * This is the place to put in driver specific hooks to release
 * driver private resources.
 * Will release the bo::reserved lock.
 */

static void ttm_bo_cleanup_memtype_use(struct ttm_buffer_object *bo)
{
        if (bo->bdev->driver->move_notify)
                bo->bdev->driver->move_notify(bo, false, NULL);

        ttm_tt_destroy(bo->ttm);
        bo->ttm = NULL;
        ttm_bo_mem_put(bo, &bo->mem);
}

static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo)
{
        int r;

        if (bo->base.resv == &bo->base._resv)
                return 0;

        BUG_ON(!dma_resv_trylock(&bo->base._resv));

        r = dma_resv_copy_fences(&bo->base._resv, bo->base.resv);
        if (r)
                dma_resv_unlock(&bo->base._resv);

        return r;
}

static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo)
{
        struct dma_resv_list *fobj;
        struct dma_fence *fence;
        int i;

        fobj = dma_resv_get_list(&bo->base._resv);
        fence = dma_resv_get_excl(&bo->base._resv);
        if (fence && !fence->ops->signaled)
                dma_fence_enable_sw_signaling(fence);

        for (i = 0; fobj && i < fobj->shared_count; ++i) {
                fence = rcu_dereference_protected(fobj->shared[i],
                                        dma_resv_held(bo->base.resv));

                if (!fence->ops->signaled)
                        dma_fence_enable_sw_signaling(fence);
        }
}

static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
{
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_bo_global *glob = bdev->glob;
        int ret;

        ret = ttm_bo_individualize_resv(bo);
        if (ret) {
                /* Last resort, if we fail to allocate memory for the
                 * fences block for the BO to become idle
                 */
                dma_resv_wait_timeout_rcu(bo->base.resv, true, false,
                                                    30 * HZ);
                spin_lock(&glob->lru_lock);
                goto error;
        }

        spin_lock(&glob->lru_lock);
        ret = dma_resv_trylock(bo->base.resv) ? 0 : -EBUSY;
        if (!ret) {
                if (dma_resv_test_signaled_rcu(&bo->base._resv, true)) {
                        ttm_bo_del_from_lru(bo);
                        spin_unlock(&glob->lru_lock);
                        if (bo->base.resv != &bo->base._resv)
                                dma_resv_unlock(&bo->base._resv);

                        ttm_bo_cleanup_memtype_use(bo);
                        dma_resv_unlock(bo->base.resv);
                        return;
                }

                ttm_bo_flush_all_fences(bo);

                /*
                 * Make NO_EVICT bos immediately available to
                 * shrinkers, now that they are queued for
                 * destruction.
                 */
                if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) {
                        bo->mem.placement &= ~TTM_PL_FLAG_NO_EVICT;
                        ttm_bo_add_to_lru(bo);
                }

                dma_resv_unlock(bo->base.resv);
        }
        if (bo->base.resv != &bo->base._resv)
                dma_resv_unlock(&bo->base._resv);

error:
        kref_get(&bo->list_kref);
        list_add_tail(&bo->ddestroy, &bdev->ddestroy);
        spin_unlock(&glob->lru_lock);

        schedule_delayed_work(&bdev->wq,
                              ((HZ / 100) < 1) ? 1 : HZ / 100);
}

/**
 * function ttm_bo_cleanup_refs
 * If bo idle, remove from delayed- and lru lists, and unref.
 * If not idle, do nothing.
 *
 * Must be called with lru_lock and reservation held, this function
 * will drop the lru lock and optionally the reservation lock before returning.
 *
 * @interruptible         Any sleeps should occur interruptibly.
 * @no_wait_gpu           Never wait for gpu. Return -EBUSY instead.
 * @unlock_resv           Unlock the reservation lock as well.
 */

static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
                               bool interruptible, bool no_wait_gpu,
                               bool unlock_resv)
{
        struct ttm_bo_global *glob = bo->bdev->glob;
        struct dma_resv *resv;
        int ret;

        if (unlikely(list_empty(&bo->ddestroy)))
                resv = bo->base.resv;
        else
                resv = &bo->base._resv;

        if (dma_resv_test_signaled_rcu(resv, true))
                ret = 0;
        else
                ret = -EBUSY;

        if (ret && !no_wait_gpu) {
                long lret;

                if (unlock_resv)
                        dma_resv_unlock(bo->base.resv);
                spin_unlock(&glob->lru_lock);

                lret = dma_resv_wait_timeout_rcu(resv, true,
                                                           interruptible,
                                                           30 * HZ);

                if (lret < 0)
                        return lret;
                else if (lret == 0)
                        return -EBUSY;

                spin_lock(&glob->lru_lock);
                if (unlock_resv && !dma_resv_trylock(bo->base.resv)) {
                        /*
                         * We raced, and lost, someone else holds the reservation now,
                         * and is probably busy in ttm_bo_cleanup_memtype_use.
                         *
                         * Even if it's not the case, because we finished waiting any
                         * delayed destruction would succeed, so just return success
                         * here.
                         */
                        spin_unlock(&glob->lru_lock);
                        return 0;
                }
                ret = 0;
        }

        if (ret || unlikely(list_empty(&bo->ddestroy))) {
                if (unlock_resv)
                        dma_resv_unlock(bo->base.resv);
                spin_unlock(&glob->lru_lock);
                return ret;
        }

        ttm_bo_del_from_lru(bo);
        list_del_init(&bo->ddestroy);
        kref_put(&bo->list_kref, ttm_bo_ref_bug);

        spin_unlock(&glob->lru_lock);
        ttm_bo_cleanup_memtype_use(bo);

        if (unlock_resv)
                dma_resv_unlock(bo->base.resv);

        return 0;
}

/**
 * Traverse the delayed list, and call ttm_bo_cleanup_refs on all
 * encountered buffers.
 */
static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
{
        struct ttm_bo_global *glob = bdev->glob;
        struct list_head removed;
        bool empty;

        INIT_LIST_HEAD(&removed);

        spin_lock(&glob->lru_lock);
        while (!list_empty(&bdev->ddestroy)) {
                struct ttm_buffer_object *bo;

                bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object,
                                      ddestroy);
                kref_get(&bo->list_kref);
                list_move_tail(&bo->ddestroy, &removed);

                if (remove_all || bo->base.resv != &bo->base._resv) {
                        spin_unlock(&glob->lru_lock);
                        dma_resv_lock(bo->base.resv, NULL);

                        spin_lock(&glob->lru_lock);
                        ttm_bo_cleanup_refs(bo, false, !remove_all, true);

                } else if (dma_resv_trylock(bo->base.resv)) {
                        ttm_bo_cleanup_refs(bo, false, !remove_all, true);
                } else {
                        spin_unlock(&glob->lru_lock);
                }

                kref_put(&bo->list_kref, ttm_bo_release_list);
                spin_lock(&glob->lru_lock);
        }
        list_splice_tail(&removed, &bdev->ddestroy);
        empty = list_empty(&bdev->ddestroy);
        spin_unlock(&glob->lru_lock);

        return empty;
}

static void ttm_bo_delayed_workqueue(struct work_struct *work)
{
        struct ttm_bo_device *bdev =
            container_of(work, struct ttm_bo_device, wq.work);

        if (!ttm_bo_delayed_delete(bdev, false))
                schedule_delayed_work(&bdev->wq,
                                      ((HZ / 100) < 1) ? 1 : HZ / 100);
}

static void ttm_bo_release(struct kref *kref)
{
        struct ttm_buffer_object *bo =
            container_of(kref, struct ttm_buffer_object, kref);
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];

        if (bo->bdev->driver->release_notify)
                bo->bdev->driver->release_notify(bo);

        drm_vma_offset_remove(&bdev->vma_manager, &bo->base.vma_node);
        ttm_mem_io_lock(man, false);
        ttm_mem_io_free_vm(bo);
        ttm_mem_io_unlock(man);
        ttm_bo_cleanup_refs_or_queue(bo);
        kref_put(&bo->list_kref, ttm_bo_release_list);
}

void ttm_bo_put(struct ttm_buffer_object *bo)
{
        kref_put(&bo->kref, ttm_bo_release);
}
EXPORT_SYMBOL(ttm_bo_put);

int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev)
{
        return cancel_delayed_work_sync(&bdev->wq);
}
EXPORT_SYMBOL(ttm_bo_lock_delayed_workqueue);

void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev, int resched)
{
        if (resched)
                schedule_delayed_work(&bdev->wq,
                                      ((HZ / 100) < 1) ? 1 : HZ / 100);
}
EXPORT_SYMBOL(ttm_bo_unlock_delayed_workqueue);

static int ttm_bo_evict(struct ttm_buffer_object *bo,
                        struct ttm_operation_ctx *ctx)
{
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_reg evict_mem;
        struct ttm_placement placement;
        int ret = 0;

        dma_resv_assert_held(bo->base.resv);

        placement.num_placement = 0;
        placement.num_busy_placement = 0;
        bdev->driver->evict_flags(bo, &placement);

        if (!placement.num_placement && !placement.num_busy_placement) {
                ret = ttm_bo_pipeline_gutting(bo);
                if (ret)
                        return ret;

                return ttm_tt_create(bo, false);
        }

        evict_mem = bo->mem;
        evict_mem.mm_node = NULL;
        evict_mem.bus.io_reserved_vm = false;
        evict_mem.bus.io_reserved_count = 0;

        ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx);
        if (ret) {
                if (ret != -ERESTARTSYS) {
                        pr_err("Failed to find memory space for buffer 0x%p eviction\n",
                               bo);
                        ttm_bo_mem_space_debug(bo, &placement);
                }
                goto out;
        }

        ret = ttm_bo_handle_move_mem(bo, &evict_mem, true, ctx);
        if (unlikely(ret)) {
                if (ret != -ERESTARTSYS)
                        pr_err("Buffer eviction failed\n");
                ttm_bo_mem_put(bo, &evict_mem);
                goto out;
        }
        bo->evicted = true;
out:
        return ret;
}

bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
                              const struct ttm_place *place)
{
        /* Don't evict this BO if it's outside of the
         * requested placement range
         */
        if (place->fpfn >= (bo->mem.start + bo->mem.size) ||
            (place->lpfn && place->lpfn <= bo->mem.start))
                return false;

        return true;
}
EXPORT_SYMBOL(ttm_bo_eviction_valuable);

/**
 * Check the target bo is allowable to be evicted or swapout, including cases:
 *
 * a. if share same reservation object with ctx->resv, have assumption
 * reservation objects should already be locked, so not lock again and
 * return true directly when either the opreation allow_reserved_eviction
 * or the target bo already is in delayed free list;
 *
 * b. Otherwise, trylock it.
 */
static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
                        struct ttm_operation_ctx *ctx, bool *locked, bool *busy)
{
        bool ret = false;

        if (bo->base.resv == ctx->resv) {
                dma_resv_assert_held(bo->base.resv);
                if (ctx->flags & TTM_OPT_FLAG_ALLOW_RES_EVICT
                    || !list_empty(&bo->ddestroy))
                        ret = true;
                *locked = false;
                if (busy)
                        *busy = false;
        } else {
                ret = dma_resv_trylock(bo->base.resv);
                *locked = ret;
                if (busy)
                        *busy = !ret;
        }

        return ret;
}

/**
 * ttm_mem_evict_wait_busy - wait for a busy BO to become available
 *
 * @busy_bo: BO which couldn't be locked with trylock
 * @ctx: operation context
 * @ticket: acquire ticket
 *
 * Try to lock a busy buffer object to avoid failing eviction.
 */
static int ttm_mem_evict_wait_busy(struct ttm_buffer_object *busy_bo,
                                   struct ttm_operation_ctx *ctx,
                                   struct ww_acquire_ctx *ticket)
{
        int r;

        if (!busy_bo || !ticket)
                return -EBUSY;

        if (ctx->interruptible)
                r = dma_resv_lock_interruptible(busy_bo->base.resv,
                                                          ticket);
        else
                r = dma_resv_lock(busy_bo->base.resv, ticket);

        /*
         * TODO: It would be better to keep the BO locked until allocation is at
         * least tried one more time, but that would mean a much larger rework
         * of TTM.
         */
        if (!r)
                dma_resv_unlock(busy_bo->base.resv);

        return r == -EDEADLK ? -EBUSY : r;
}

static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
                               uint32_t mem_type,
                               const struct ttm_place *place,
                               struct ttm_operation_ctx *ctx,
                               struct ww_acquire_ctx *ticket)
{
        struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
        struct ttm_bo_global *glob = bdev->glob;
        struct ttm_mem_type_manager *man = &bdev->man[mem_type];
        bool locked = false;
        unsigned i;
        int ret;

        spin_lock(&glob->lru_lock);
        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                list_for_each_entry(bo, &man->lru[i], lru) {
                        bool busy;

                        if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
                                                            &busy)) {
                                if (busy && !busy_bo && ticket !=
                                    dma_resv_locking_ctx(bo->base.resv))
                                        busy_bo = bo;
                                continue;
                        }

                        if (place && !bdev->driver->eviction_valuable(bo,
                                                                      place)) {
                                if (locked)
                                        dma_resv_unlock(bo->base.resv);
                                continue;
                        }
                        break;
                }

                /* If the inner loop terminated early, we have our candidate */
                if (&bo->lru != &man->lru[i])
                        break;

                bo = NULL;
        }

        if (!bo) {
                if (busy_bo)
                        kref_get(&busy_bo->list_kref);
                spin_unlock(&glob->lru_lock);
                ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket);
                if (busy_bo)
                        kref_put(&busy_bo->list_kref, ttm_bo_release_list);
                return ret;
        }

        kref_get(&bo->list_kref);

        if (!list_empty(&bo->ddestroy)) {
                ret = ttm_bo_cleanup_refs(bo, ctx->interruptible,
                                          ctx->no_wait_gpu, locked);
                kref_put(&bo->list_kref, ttm_bo_release_list);
                return ret;
        }

        ttm_bo_del_from_lru(bo);
        spin_unlock(&glob->lru_lock);

        ret = ttm_bo_evict(bo, ctx);
        if (locked) {
                ttm_bo_unreserve(bo);
        } else {
                spin_lock(&glob->lru_lock);
                ttm_bo_add_to_lru(bo);
                spin_unlock(&glob->lru_lock);
        }

        kref_put(&bo->list_kref, ttm_bo_release_list);
        return ret;
}

void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem)
{
        struct ttm_mem_type_manager *man = &bo->bdev->man[mem->mem_type];

        if (mem->mm_node)
                (*man->func->put_node)(man, mem);
}
EXPORT_SYMBOL(ttm_bo_mem_put);

/**
 * Add the last move fence to the BO and reserve a new shared slot.
 */
static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
                                 struct ttm_mem_type_manager *man,
                                 struct ttm_mem_reg *mem)
{
        struct dma_fence *fence;
        int ret;

        spin_lock(&man->move_lock);
        fence = dma_fence_get(man->move);
        spin_unlock(&man->move_lock);

        if (fence) {
                dma_resv_add_shared_fence(bo->base.resv, fence);

                ret = dma_resv_reserve_shared(bo->base.resv, 1);
                if (unlikely(ret)) {
                        dma_fence_put(fence);
                        return ret;
                }

                dma_fence_put(bo->moving);
                bo->moving = fence;
        }

        return 0;
}

/**
 * Repeatedly evict memory from the LRU for @mem_type until we create enough
 * space, or we've evicted everything and there isn't enough space.
 */
static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
                                  const struct ttm_place *place,
                                  struct ttm_mem_reg *mem,
                                  struct ttm_operation_ctx *ctx)
{
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
        struct ww_acquire_ctx *ticket;
        int ret;

        ticket = dma_resv_locking_ctx(bo->base.resv);
        do {
                ret = (*man->func->get_node)(man, bo, place, mem);
                if (unlikely(ret != 0))
                        return ret;
                if (mem->mm_node)
                        break;
                ret = ttm_mem_evict_first(bdev, mem->mem_type, place, ctx,
                                          ticket);
                if (unlikely(ret != 0))
                        return ret;
        } while (1);

        return ttm_bo_add_move_fence(bo, man, mem);
}

static uint32_t ttm_bo_select_caching(struct ttm_mem_type_manager *man,
                                      uint32_t cur_placement,
                                      uint32_t proposed_placement)
{
        uint32_t caching = proposed_placement & TTM_PL_MASK_CACHING;
        uint32_t result = proposed_placement & ~TTM_PL_MASK_CACHING;

        /**
         * Keep current caching if possible.
         */

        if ((cur_placement & caching) != 0)
                result |= (cur_placement & caching);
        else if ((man->default_caching & caching) != 0)
                result |= man->default_caching;
        else if ((TTM_PL_FLAG_CACHED & caching) != 0)
                result |= TTM_PL_FLAG_CACHED;

        else if ((TTM_PL_FLAG_WC & caching) != 0)
                result |= TTM_PL_FLAG_WC;
        else if ((TTM_PL_FLAG_UNCACHED & caching) != 0)
                result |= TTM_PL_FLAG_UNCACHED;

        return result;
}

static bool ttm_bo_mt_compatible(struct ttm_mem_type_manager *man,
                                 uint32_t mem_type,
                                 const struct ttm_place *place,
                                 uint32_t *masked_placement)
{
        uint32_t cur_flags = ttm_bo_type_flags(mem_type);

        if ((cur_flags & place->flags & TTM_PL_MASK_MEM) == 0)
                return false;

        if ((place->flags & man->available_caching) == 0)
                return false;

        cur_flags |= (place->flags & man->available_caching);

        *masked_placement = cur_flags;
        return true;
}

/**
 * ttm_bo_mem_placement - check if placement is compatible
 * @bo: BO to find memory for
 * @place: where to search
 * @mem: the memory object to fill in
 * @ctx: operation context
 *
 * Check if placement is compatible and fill in mem structure.
 * Returns -EBUSY if placement won't work or negative error code.
 * 0 when placement can be used.
 */
static int ttm_bo_mem_placement(struct ttm_buffer_object *bo,
                                const struct ttm_place *place,
                                struct ttm_mem_reg *mem,
                                struct ttm_operation_ctx *ctx)
{
        struct ttm_bo_device *bdev = bo->bdev;
        uint32_t mem_type = TTM_PL_SYSTEM;
        struct ttm_mem_type_manager *man;
        uint32_t cur_flags = 0;
        int ret;

        ret = ttm_mem_type_from_place(place, &mem_type);
        if (ret)
                return ret;

        man = &bdev->man[mem_type];
        if (!man->has_type || !man->use_type)
                return -EBUSY;

        if (!ttm_bo_mt_compatible(man, mem_type, place, &cur_flags))
                return -EBUSY;

        cur_flags = ttm_bo_select_caching(man, bo->mem.placement, cur_flags);
        /*
         * Use the access and other non-mapping-related flag bits from
         * the memory placement flags to the current flags
         */
        ttm_flag_masked(&cur_flags, place->flags, ~TTM_PL_MASK_MEMTYPE);

        mem->mem_type = mem_type;
        mem->placement = cur_flags;

        if (bo->mem.mem_type < mem_type && !list_empty(&bo->lru)) {
                spin_lock(&bo->bdev->glob->lru_lock);
                ttm_bo_del_from_lru(bo);
                ttm_bo_add_mem_to_lru(bo, mem);
                spin_unlock(&bo->bdev->glob->lru_lock);
        }

        return 0;
}

/**
 * Creates space for memory region @mem according to its type.
 *
 * This function first searches for free space in compatible memory types in
 * the priority order defined by the driver.  If free space isn't found, then
 * ttm_bo_mem_force_space is attempted in priority order to evict and find
 * space.
 */
int ttm_bo_mem_space(struct ttm_buffer_object *bo,
                        struct ttm_placement *placement,
                        struct ttm_mem_reg *mem,
                        struct ttm_operation_ctx *ctx)
{
        struct ttm_bo_device *bdev = bo->bdev;
        bool type_found = false;
        int i, ret;

        ret = dma_resv_reserve_shared(bo->base.resv, 1);
        if (unlikely(ret))
                return ret;

        mem->mm_node = NULL;
        for (i = 0; i < placement->num_placement; ++i) {
                const struct ttm_place *place = &placement->placement[i];
                struct ttm_mem_type_manager *man;

                ret = ttm_bo_mem_placement(bo, place, mem, ctx);
                if (ret == -EBUSY)
                        continue;
                if (ret)
                        goto error;

                type_found = true;
                mem->mm_node = NULL;
                if (mem->mem_type == TTM_PL_SYSTEM)
                        return 0;

                man = &bdev->man[mem->mem_type];
                ret = (*man->func->get_node)(man, bo, place, mem);
                if (unlikely(ret))
                        goto error;

                if (mem->mm_node) {
                        ret = ttm_bo_add_move_fence(bo, man, mem);
                        if (unlikely(ret)) {
                                (*man->func->put_node)(man, mem);
                                goto error;
                        }
                        return 0;
                }
        }

        for (i = 0; i < placement->num_busy_placement; ++i) {
                const struct ttm_place *place = &placement->busy_placement[i];

                ret = ttm_bo_mem_placement(bo, place, mem, ctx);
                if (ret == -EBUSY)
                        continue;
                if (ret)
                        goto error;

                type_found = true;
                mem->mm_node = NULL;
                if (mem->mem_type == TTM_PL_SYSTEM)
                        return 0;

                ret = ttm_bo_mem_force_space(bo, place, mem, ctx);
                if (ret == 0 && mem->mm_node)
                        return 0;

                if (ret && ret != -EBUSY)
                        goto error;
        }

        ret = -ENOMEM;
        if (!type_found) {
                pr_err(TTM_PFX "No compatible memory type found\n");
                ret = -EINVAL;
        }

error:
        if (bo->mem.mem_type == TTM_PL_SYSTEM && !list_empty(&bo->lru)) {
                spin_lock(&bo->bdev->glob->lru_lock);
                ttm_bo_move_to_lru_tail(bo, NULL);
                spin_unlock(&bo->bdev->glob->lru_lock);
        }

        return ret;
}
EXPORT_SYMBOL(ttm_bo_mem_space);

static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
                              struct ttm_placement *placement,
                              struct ttm_operation_ctx *ctx)
{
        int ret = 0;
        struct ttm_mem_reg mem;

        dma_resv_assert_held(bo->base.resv);

        mem.num_pages = bo->num_pages;
        mem.size = mem.num_pages << PAGE_SHIFT;
        mem.page_alignment = bo->mem.page_alignment;
        mem.bus.io_reserved_vm = false;
        mem.bus.io_reserved_count = 0;
        /*
         * Determine where to move the buffer.
         */
        ret = ttm_bo_mem_space(bo, placement, &mem, ctx);
        if (ret)
                goto out_unlock;
        ret = ttm_bo_handle_move_mem(bo, &mem, false, ctx);
out_unlock:
        if (ret && mem.mm_node)
                ttm_bo_mem_put(bo, &mem);
        return ret;
}

static bool ttm_bo_places_compat(const struct ttm_place *places,
                                 unsigned num_placement,
                                 struct ttm_mem_reg *mem,
                                 uint32_t *new_flags)
{
        unsigned i;

        for (i = 0; i < num_placement; i++) {
                const struct ttm_place *heap = &places[i];

                if (mem->mm_node && (mem->start < heap->fpfn ||
                     (heap->lpfn != 0 && (mem->start + mem->num_pages) > heap->lpfn)))
                        continue;

                *new_flags = heap->flags;
                if ((*new_flags & mem->placement & TTM_PL_MASK_CACHING) &&
                    (*new_flags & mem->placement & TTM_PL_MASK_MEM) &&
                    (!(*new_flags & TTM_PL_FLAG_CONTIGUOUS) ||
                     (mem->placement & TTM_PL_FLAG_CONTIGUOUS)))
                        return true;
        }
        return false;
}

bool ttm_bo_mem_compat(struct ttm_placement *placement,
                       struct ttm_mem_reg *mem,
                       uint32_t *new_flags)
{
        if (ttm_bo_places_compat(placement->placement, placement->num_placement,
                                 mem, new_flags))
                return true;

        if ((placement->busy_placement != placement->placement ||
             placement->num_busy_placement > placement->num_placement) &&
            ttm_bo_places_compat(placement->busy_placement,
                                 placement->num_busy_placement,
                                 mem, new_flags))
                return true;

        return false;
}
EXPORT_SYMBOL(ttm_bo_mem_compat);

int ttm_bo_validate(struct ttm_buffer_object *bo,
                    struct ttm_placement *placement,
                    struct ttm_operation_ctx *ctx)
{
        int ret;
        uint32_t new_flags;

        dma_resv_assert_held(bo->base.resv);
        /*
         * Check whether we need to move buffer.
         */
        if (!ttm_bo_mem_compat(placement, &bo->mem, &new_flags)) {
                ret = ttm_bo_move_buffer(bo, placement, ctx);
                if (ret)
                        return ret;
        } else {
                /*
                 * Use the access and other non-mapping-related flag bits from
                 * the compatible memory placement flags to the active flags
                 */
                ttm_flag_masked(&bo->mem.placement, new_flags,
                                ~TTM_PL_MASK_MEMTYPE);
        }
        /*
         * We might need to add a TTM.
         */
        if (bo->mem.mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
                ret = ttm_tt_create(bo, true);
                if (ret)
                        return ret;
        }
        return 0;
}
EXPORT_SYMBOL(ttm_bo_validate);

int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
                         struct ttm_buffer_object *bo,
                         unsigned long size,
                         enum ttm_bo_type type,
                         struct ttm_placement *placement,
                         uint32_t page_alignment,
                         struct ttm_operation_ctx *ctx,
                         size_t acc_size,
                         struct sg_table *sg,
                         struct dma_resv *resv,
                         void (*destroy) (struct ttm_buffer_object *))
{
        int ret = 0;
        unsigned long num_pages;
        struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
        bool locked;

        ret = ttm_mem_global_alloc(mem_glob, acc_size, ctx);
        if (ret) {
                pr_err("Out of kernel memory\n");
                if (destroy)
                        (*destroy)(bo);
                else
                        kfree(bo);
                return -ENOMEM;
        }

        num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
        if (num_pages == 0) {
                pr_err("Illegal buffer object size\n");
                if (destroy)
                        (*destroy)(bo);
                else
                        kfree(bo);
                ttm_mem_global_free(mem_glob, acc_size);
                return -EINVAL;
        }
        bo->destroy = destroy ? destroy : ttm_bo_default_destroy;

        kref_init(&bo->kref);
        kref_init(&bo->list_kref);
        atomic_set(&bo->cpu_writers, 0);
        INIT_LIST_HEAD(&bo->lru);
        INIT_LIST_HEAD(&bo->ddestroy);
        INIT_LIST_HEAD(&bo->swap);
        INIT_LIST_HEAD(&bo->io_reserve_lru);
        mutex_init(&bo->wu_mutex);
        bo->bdev = bdev;
        bo->type = type;
        bo->num_pages = num_pages;
        bo->mem.size = num_pages << PAGE_SHIFT;
        bo->mem.mem_type = TTM_PL_SYSTEM;
        bo->mem.num_pages = bo->num_pages;
        bo->mem.mm_node = NULL;
        bo->mem.page_alignment = page_alignment;
        bo->mem.bus.io_reserved_vm = false;
        bo->mem.bus.io_reserved_count = 0;
        bo->moving = NULL;
        bo->mem.placement = (TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED);
        bo->acc_size = acc_size;
        bo->sg = sg;
        if (resv) {
                bo->base.resv = resv;
                dma_resv_assert_held(bo->base.resv);
        } else {
                bo->base.resv = &bo->base._resv;
        }
        if (!ttm_bo_uses_embedded_gem_object(bo)) {
                /*
                 * bo.gem is not initialized, so we have to setup the
                 * struct elements we want use regardless.
                 */
                dma_resv_init(&bo->base._resv);
                drm_vma_node_reset(&bo->base.vma_node);
        }
        atomic_inc(&bo->bdev->glob->bo_count);

        /*
         * For ttm_bo_type_device buffers, allocate
         * address space from the device.
         */
        if (bo->type == ttm_bo_type_device ||
            bo->type == ttm_bo_type_sg)
                ret = drm_vma_offset_add(&bdev->vma_manager, &bo->base.vma_node,
                                         bo->mem.num_pages);

        /* passed reservation objects should already be locked,
         * since otherwise lockdep will be angered in radeon.
         */
        if (!resv) {
                locked = dma_resv_trylock(bo->base.resv);
                WARN_ON(!locked);
        }

        if (likely(!ret))
                ret = ttm_bo_validate(bo, placement, ctx);

        if (unlikely(ret)) {
                if (!resv)
                        ttm_bo_unreserve(bo);

                ttm_bo_put(bo);
                return ret;
        }

        if (resv && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
                spin_lock(&bdev->glob->lru_lock);
                ttm_bo_add_to_lru(bo);
                spin_unlock(&bdev->glob->lru_lock);
        }

        return ret;
}
EXPORT_SYMBOL(ttm_bo_init_reserved);

int ttm_bo_init(struct ttm_bo_device *bdev,
                struct ttm_buffer_object *bo,
                unsigned long size,
                enum ttm_bo_type type,
                struct ttm_placement *placement,
                uint32_t page_alignment,
                bool interruptible,
                size_t acc_size,
                struct sg_table *sg,
                struct dma_resv *resv,
                void (*destroy) (struct ttm_buffer_object *))
{
        struct ttm_operation_ctx ctx = { interruptible, false };
        int ret;

        ret = ttm_bo_init_reserved(bdev, bo, size, type, placement,
                                   page_alignment, &ctx, acc_size,
                                   sg, resv, destroy);
        if (ret)
                return ret;

        if (!resv)
                ttm_bo_unreserve(bo);

        return 0;
}
EXPORT_SYMBOL(ttm_bo_init);

size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
                       unsigned long bo_size,
                       unsigned struct_size)
{
        unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
        size_t size = 0;

        size += ttm_round_pot(struct_size);
        size += ttm_round_pot(npages * sizeof(void *));
        size += ttm_round_pot(sizeof(struct ttm_tt));
        return size;
}
EXPORT_SYMBOL(ttm_bo_acc_size);

size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
                           unsigned long bo_size,
                           unsigned struct_size)
{
        unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
        size_t size = 0;

        size += ttm_round_pot(struct_size);
        size += ttm_round_pot(npages * (2*sizeof(void *) + sizeof(dma_addr_t)));
        size += ttm_round_pot(sizeof(struct ttm_dma_tt));
        return size;
}
EXPORT_SYMBOL(ttm_bo_dma_acc_size);

int ttm_bo_create(struct ttm_bo_device *bdev,
                        unsigned long size,
                        enum ttm_bo_type type,
                        struct ttm_placement *placement,
                        uint32_t page_alignment,
                        bool interruptible,
                        struct ttm_buffer_object **p_bo)
{
        struct ttm_buffer_object *bo;
        size_t acc_size;
        int ret;

        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
        if (unlikely(bo == NULL))
                return -ENOMEM;

        acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct ttm_buffer_object));
        ret = ttm_bo_init(bdev, bo, size, type, placement, page_alignment,
                          interruptible, acc_size,
                          NULL, NULL, NULL);
        if (likely(ret == 0))
                *p_bo = bo;

        return ret;
}
EXPORT_SYMBOL(ttm_bo_create);

static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
                                   unsigned mem_type)
{
        struct ttm_operation_ctx ctx = {
                .interruptible = false,
                .no_wait_gpu = false,
                .flags = TTM_OPT_FLAG_FORCE_ALLOC
        };
        struct ttm_mem_type_manager *man = &bdev->man[mem_type];
        struct ttm_bo_global *glob = bdev->glob;
        struct dma_fence *fence;
        int ret;
        unsigned i;

        /*
         * Can't use standard list traversal since we're unlocking.
         */

        spin_lock(&glob->lru_lock);
        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                while (!list_empty(&man->lru[i])) {
                        spin_unlock(&glob->lru_lock);
                        ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx,
                                                  NULL);
                        if (ret)
                                return ret;
                        spin_lock(&glob->lru_lock);
                }
        }
        spin_unlock(&glob->lru_lock);

        spin_lock(&man->move_lock);
        fence = dma_fence_get(man->move);
        spin_unlock(&man->move_lock);

        if (fence) {
                ret = dma_fence_wait(fence, false);
                dma_fence_put(fence);
                if (ret)
                        return ret;
        }

        return 0;
}

int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type)
{
        struct ttm_mem_type_manager *man;
        int ret = -EINVAL;

        if (mem_type >= TTM_NUM_MEM_TYPES) {
                pr_err("Illegal memory type %d\n", mem_type);
                return ret;
        }
        man = &bdev->man[mem_type];

        if (!man->has_type) {
                pr_err("Trying to take down uninitialized memory manager type %u\n",
                       mem_type);
                return ret;
        }

        man->use_type = false;
        man->has_type = false;

        ret = 0;
        if (mem_type > 0) {
                ret = ttm_bo_force_list_clean(bdev, mem_type);
                if (ret) {
                        pr_err("Cleanup eviction failed\n");
                        return ret;
                }

                ret = (*man->func->takedown)(man);
        }

        dma_fence_put(man->move);
        man->move = NULL;

        return ret;
}
EXPORT_SYMBOL(ttm_bo_clean_mm);

int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type)
{
        struct ttm_mem_type_manager *man = &bdev->man[mem_type];

        if (mem_type == 0 || mem_type >= TTM_NUM_MEM_TYPES) {
                pr_err("Illegal memory manager memory type %u\n", mem_type);
                return -EINVAL;
        }

        if (!man->has_type) {
                pr_err("Memory type %u has not been initialized\n", mem_type);
                return 0;
        }

        return ttm_bo_force_list_clean(bdev, mem_type);
}
EXPORT_SYMBOL(ttm_bo_evict_mm);

int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
                        unsigned long p_size)
{
        int ret;
        struct ttm_mem_type_manager *man;
        unsigned i;

        BUG_ON(type >= TTM_NUM_MEM_TYPES);
        man = &bdev->man[type];
        BUG_ON(man->has_type);
        man->io_reserve_fastpath = true;
        man->use_io_reserve_lru = false;
        mutex_init(&man->io_reserve_mutex);
        spin_lock_init(&man->move_lock);
        INIT_LIST_HEAD(&man->io_reserve_lru);

        ret = bdev->driver->init_mem_type(bdev, type, man);
        if (ret)
                return ret;
        man->bdev = bdev;

        if (type != TTM_PL_SYSTEM) {
                ret = (*man->func->init)(man, p_size);
                if (ret)
                        return ret;
        }
        man->has_type = true;
        man->use_type = true;
        man->size = p_size;

        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
                INIT_LIST_HEAD(&man->lru[i]);
        man->move = NULL;

        return 0;
}
EXPORT_SYMBOL(ttm_bo_init_mm);

static void ttm_bo_global_kobj_release(struct kobject *kobj)
{
        struct ttm_bo_global *glob =
                container_of(kobj, struct ttm_bo_global, kobj);

        __free_page(glob->dummy_read_page);
}

static void ttm_bo_global_release(void)
{
        struct ttm_bo_global *glob = &ttm_bo_glob;

        mutex_lock(&ttm_global_mutex);
        if (--ttm_bo_glob_use_count > 0)
                goto out;

        kobject_del(&glob->kobj);
        kobject_put(&glob->kobj);
        ttm_mem_global_release(&ttm_mem_glob);
        memset(glob, 0, sizeof(*glob));
out:
        mutex_unlock(&ttm_global_mutex);
}

static int ttm_bo_global_init(void)
{
        struct ttm_bo_global *glob = &ttm_bo_glob;
        int ret = 0;
        unsigned i;

        mutex_lock(&ttm_global_mutex);
        if (++ttm_bo_glob_use_count > 1)
                goto out;

        ret = ttm_mem_global_init(&ttm_mem_glob);
        if (ret)
                goto out;

        spin_lock_init(&glob->lru_lock);
        glob->mem_glob = &ttm_mem_glob;
        glob->mem_glob->bo_glob = glob;
        glob->dummy_read_page = alloc_page(__GFP_ZERO | GFP_DMA32);

        if (unlikely(glob->dummy_read_page == NULL)) {
                ret = -ENOMEM;
                goto out;
        }

        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
                INIT_LIST_HEAD(&glob->swap_lru[i]);
        INIT_LIST_HEAD(&glob->device_list);
        atomic_set(&glob->bo_count, 0);

        ret = kobject_init_and_add(
                &glob->kobj, &ttm_bo_glob_kobj_type, ttm_get_kobj(), "buffer_objects");
        if (unlikely(ret != 0))
                kobject_put(&glob->kobj);
out:
        mutex_unlock(&ttm_global_mutex);
        return ret;
}

int ttm_bo_device_release(struct ttm_bo_device *bdev)
{
        int ret = 0;
        unsigned i = TTM_NUM_MEM_TYPES;
        struct ttm_mem_type_manager *man;
        struct ttm_bo_global *glob = bdev->glob;

        while (i--) {
                man = &bdev->man[i];
                if (man->has_type) {
                        man->use_type = false;
                        if ((i != TTM_PL_SYSTEM) && ttm_bo_clean_mm(bdev, i)) {
                                ret = -EBUSY;
                                pr_err("DRM memory manager type %d is not clean\n",
                                       i);
                        }
                        man->has_type = false;
                }
        }

        mutex_lock(&ttm_global_mutex);
        list_del(&bdev->device_list);
        mutex_unlock(&ttm_global_mutex);

        cancel_delayed_work_sync(&bdev->wq);

        if (ttm_bo_delayed_delete(bdev, true))
                pr_debug("Delayed destroy list was clean\n");

        spin_lock(&glob->lru_lock);
        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i)
                if (list_empty(&bdev->man[0].lru[0]))
                        pr_debug("Swap list %d was clean\n", i);
        spin_unlock(&glob->lru_lock);

        drm_vma_offset_manager_destroy(&bdev->vma_manager);

        if (!ret)
                ttm_bo_global_release();

        return ret;
}
EXPORT_SYMBOL(ttm_bo_device_release);

int ttm_bo_device_init(struct ttm_bo_device *bdev,
                       struct ttm_bo_driver *driver,
                       struct address_space *mapping,
                       bool need_dma32)
{
        struct ttm_bo_global *glob = &ttm_bo_glob;
        int ret;

        ret = ttm_bo_global_init();
        if (ret)
                return ret;

        bdev->driver = driver;

        memset(bdev->man, 0, sizeof(bdev->man));

        /*
         * Initialize the system memory buffer type.
         * Other types need to be driver / IOCTL initialized.
         */
        ret = ttm_bo_init_mm(bdev, TTM_PL_SYSTEM, 0);
        if (unlikely(ret != 0))
                goto out_no_sys;

        drm_vma_offset_manager_init(&bdev->vma_manager,
                                    DRM_FILE_PAGE_OFFSET_START,
                                    DRM_FILE_PAGE_OFFSET_SIZE);
        INIT_DELAYED_WORK(&bdev->wq, ttm_bo_delayed_workqueue);
        INIT_LIST_HEAD(&bdev->ddestroy);
        bdev->dev_mapping = mapping;
        bdev->glob = glob;
        bdev->need_dma32 = need_dma32;
        mutex_lock(&ttm_global_mutex);
        list_add_tail(&bdev->device_list, &glob->device_list);
        mutex_unlock(&ttm_global_mutex);

        return 0;
out_no_sys:
        ttm_bo_global_release();
        return ret;
}
EXPORT_SYMBOL(ttm_bo_device_init);

/*
 * buffer object vm functions.
 */

bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
{
        struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];

        if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
                if (mem->mem_type == TTM_PL_SYSTEM)
                        return false;

                if (man->flags & TTM_MEMTYPE_FLAG_CMA)
                        return false;

                if (mem->placement & TTM_PL_FLAG_CACHED)
                        return false;
        }
        return true;
}

void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo)
{
        struct ttm_bo_device *bdev = bo->bdev;

        drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping);
        ttm_mem_io_free_vm(bo);
}

void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo)
{
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];

        ttm_mem_io_lock(man, false);
        ttm_bo_unmap_virtual_locked(bo);
        ttm_mem_io_unlock(man);
}


EXPORT_SYMBOL(ttm_bo_unmap_virtual);

int ttm_bo_wait(struct ttm_buffer_object *bo,
                bool interruptible, bool no_wait)
{
        long timeout = 15 * HZ;

        if (no_wait) {
                if (dma_resv_test_signaled_rcu(bo->base.resv, true))
                        return 0;
                else
                        return -EBUSY;
        }

        timeout = dma_resv_wait_timeout_rcu(bo->base.resv, true,
                                                      interruptible, timeout);
        if (timeout < 0)
                return timeout;

        if (timeout == 0)
                return -EBUSY;

        dma_resv_add_excl_fence(bo->base.resv, NULL);
        return 0;
}
EXPORT_SYMBOL(ttm_bo_wait);

int ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait)
{
        int ret = 0;

        /*
         * Using ttm_bo_reserve makes sure the lru lists are updated.
         */

        ret = ttm_bo_reserve(bo, true, no_wait, NULL);
        if (unlikely(ret != 0))
                return ret;
        ret = ttm_bo_wait(bo, true, no_wait);
        if (likely(ret == 0))
                atomic_inc(&bo->cpu_writers);
        ttm_bo_unreserve(bo);
        return ret;
}
EXPORT_SYMBOL(ttm_bo_synccpu_write_grab);

void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo)
{
        atomic_dec(&bo->cpu_writers);
}
EXPORT_SYMBOL(ttm_bo_synccpu_write_release);

/**
 * A buffer object shrink method that tries to swap out the first
 * buffer object on the bo_global::swap_lru list.
 */
int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx)
{
        struct ttm_buffer_object *bo;
        int ret = -EBUSY;
        bool locked;
        unsigned i;

        spin_lock(&glob->lru_lock);
        for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
                list_for_each_entry(bo, &glob->swap_lru[i], swap) {
                        if (ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
                                                           NULL)) {
                                ret = 0;
                                break;
                        }
                }
                if (!ret)
                        break;
        }

        if (ret) {
                spin_unlock(&glob->lru_lock);
                return ret;
        }

        kref_get(&bo->list_kref);

        if (!list_empty(&bo->ddestroy)) {
                ret = ttm_bo_cleanup_refs(bo, false, false, locked);
                kref_put(&bo->list_kref, ttm_bo_release_list);
                return ret;
        }

        ttm_bo_del_from_lru(bo);
        spin_unlock(&glob->lru_lock);

        /**
         * Move to system cached
         */

        if (bo->mem.mem_type != TTM_PL_SYSTEM ||
            bo->ttm->caching_state != tt_cached) {
                struct ttm_operation_ctx ctx = { false, false };
                struct ttm_mem_reg evict_mem;

                evict_mem = bo->mem;
                evict_mem.mm_node = NULL;
                evict_mem.placement = TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED;
                evict_mem.mem_type = TTM_PL_SYSTEM;

                ret = ttm_bo_handle_move_mem(bo, &evict_mem, true, &ctx);
                if (unlikely(ret != 0))
                        goto out;
        }

        /**
         * Make sure BO is idle.
         */

        ret = ttm_bo_wait(bo, false, false);
        if (unlikely(ret != 0))
                goto out;

        ttm_bo_unmap_virtual(bo);

        /**
         * Swap out. Buffer will be swapped in again as soon as
         * anyone tries to access a ttm page.
         */

        if (bo->bdev->driver->swap_notify)
                bo->bdev->driver->swap_notify(bo);

        ret = ttm_tt_swapout(bo->ttm, bo->persistent_swap_storage);
out:

        /**
         *
         * Unreserve without putting on LRU to avoid swapping out an
         * already swapped buffer.
         */
        if (locked)
                dma_resv_unlock(bo->base.resv);
        kref_put(&bo->list_kref, ttm_bo_release_list);
        return ret;
}
EXPORT_SYMBOL(ttm_bo_swapout);

void ttm_bo_swapout_all(struct ttm_bo_device *bdev)
{
        struct ttm_operation_ctx ctx = {
                .interruptible = false,
                .no_wait_gpu = false
        };

        while (ttm_bo_swapout(bdev->glob, &ctx) == 0)
                ;
}
EXPORT_SYMBOL(ttm_bo_swapout_all);

/**
 * ttm_bo_wait_unreserved - interruptible wait for a buffer object to become
 * unreserved
 *
 * @bo: Pointer to buffer
 */
int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo)
{
        int ret;

        /*
         * In the absense of a wait_unlocked API,
         * Use the bo::wu_mutex to avoid triggering livelocks due to
         * concurrent use of this function. Note that this use of
         * bo::wu_mutex can go away if we change locking order to
         * mmap_sem -> bo::reserve.
         */
        ret = mutex_lock_interruptible(&bo->wu_mutex);
        if (unlikely(ret != 0))
                return -ERESTARTSYS;
        if (!dma_resv_is_locked(bo->base.resv))
                goto out_unlock;
        ret = dma_resv_lock_interruptible(bo->base.resv, NULL);
        if (ret == -EINTR)
                ret = -ERESTARTSYS;
        if (unlikely(ret != 0))
                goto out_unlock;
        dma_resv_unlock(bo->base.resv);

out_unlock:
        mutex_unlock(&bo->wu_mutex);
        return ret;
}