ttm_object.c

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/**************************************************************************
 *
 * Copyright (c) 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_object.h>
#include <drm/ttm/ttm_module.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/atomic.h>

struct ttm_object_file {
    struct ttm_object_device *tdev;
    rwlock_t lock;
    struct list_head ref_list;
    struct drm_open_hash ref_hash[TTM_REF_NUM];
    struct kref refcount;
};

struct ttm_object_device {
    rwlock_t object_lock;
    struct drm_open_hash object_hash;
    atomic_t object_count;
    struct ttm_mem_global *mem_glob;
};

struct ttm_ref_object {
    struct drm_hash_item hash;
    struct list_head head;
    struct kref kref;
    enum ttm_ref_type ref_type;
    struct ttm_base_object *obj;
    struct ttm_object_file *tfile;
};

static inline struct ttm_object_file *
ttm_object_file_ref(struct ttm_object_file *tfile)
{
    kref_get(&tfile->refcount);
    return tfile;
}

static void ttm_object_file_destroy(struct kref *kref)
{
    struct ttm_object_file *tfile =
        container_of(kref, struct ttm_object_file, refcount);

    kfree(tfile);
}


static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
{
    struct ttm_object_file *tfile = *p_tfile;

    *p_tfile = NULL;
    kref_put(&tfile->refcount, ttm_object_file_destroy);
}


int ttm_base_object_init(struct ttm_object_file *tfile,
             struct ttm_base_object *base,
             bool shareable,
             enum ttm_object_type object_type,
             void (*refcount_release) (struct ttm_base_object **),
             void (*ref_obj_release) (struct ttm_base_object *,
                          enum ttm_ref_type ref_type))
{
    struct ttm_object_device *tdev = tfile->tdev;
    int ret;

    base->shareable = shareable;
    base->tfile = ttm_object_file_ref(tfile);
    base->refcount_release = refcount_release;
    base->ref_obj_release = ref_obj_release;
    base->object_type = object_type;
    write_lock(&tdev->object_lock);
    kref_init(&base->refcount);
    ret = drm_ht_just_insert_please(&tdev->object_hash,
                    &base->hash,
                    (unsigned long)base, 31, 0, 0);
    write_unlock(&tdev->object_lock);
    if (unlikely(ret != 0))
        goto out_err0;

    ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
    if (unlikely(ret != 0))
        goto out_err1;

    ttm_base_object_unref(&base);

    return 0;
out_err1:
    (void)drm_ht_remove_item(&tdev->object_hash, &base->hash);
out_err0:
    return ret;
}
EXPORT_SYMBOL(ttm_base_object_init);

static void ttm_release_base(struct kref *kref)
{
    struct ttm_base_object *base =
        container_of(kref, struct ttm_base_object, refcount);
    struct ttm_object_device *tdev = base->tfile->tdev;

    (void)drm_ht_remove_item(&tdev->object_hash, &base->hash);
    write_unlock(&tdev->object_lock);
    if (base->refcount_release) {
        ttm_object_file_unref(&base->tfile);
        base->refcount_release(&base);
    }
    write_lock(&tdev->object_lock);
}

void ttm_base_object_unref(struct ttm_base_object **p_base)
{
    struct ttm_base_object *base = *p_base;
    struct ttm_object_device *tdev = base->tfile->tdev;

    *p_base = NULL;

    /*
     * Need to take the lock here to avoid racing with
     * users trying to look up the object.
     */

    write_lock(&tdev->object_lock);
    kref_put(&base->refcount, ttm_release_base);
    write_unlock(&tdev->object_lock);
}
EXPORT_SYMBOL(ttm_base_object_unref);

struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
                           uint32_t key)
{
    struct ttm_object_device *tdev = tfile->tdev;
    struct ttm_base_object *base;
    struct drm_hash_item *hash;
    int ret;

    read_lock(&tdev->object_lock);
    ret = drm_ht_find_item(&tdev->object_hash, key, &hash);

    if (likely(ret == 0)) {
        base = drm_hash_entry(hash, struct ttm_base_object, hash);
        kref_get(&base->refcount);
    }
    read_unlock(&tdev->object_lock);

    if (unlikely(ret != 0))
        return NULL;

    if (tfile != base->tfile && !base->shareable) {
        pr_err("Attempted access of non-shareable object\n");
        ttm_base_object_unref(&base);
        return NULL;
    }

    return base;
}
EXPORT_SYMBOL(ttm_base_object_lookup);

int ttm_ref_object_add(struct ttm_object_file *tfile,
               struct ttm_base_object *base,
               enum ttm_ref_type ref_type, bool *existed)
{
    struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
    struct ttm_ref_object *ref;
    struct drm_hash_item *hash;
    struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
    int ret = -EINVAL;

    if (existed != NULL)
        *existed = true;

    while (ret == -EINVAL) {
        read_lock(&tfile->lock);
        ret = drm_ht_find_item(ht, base->hash.key, &hash);

        if (ret == 0) {
            ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
            kref_get(&ref->kref);
            read_unlock(&tfile->lock);
            break;
        }

        read_unlock(&tfile->lock);
        ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
                       false, false);
        if (unlikely(ret != 0))
            return ret;
        ref = kmalloc(sizeof(*ref), GFP_KERNEL);
        if (unlikely(ref == NULL)) {
            ttm_mem_global_free(mem_glob, sizeof(*ref));
            return -ENOMEM;
        }

        ref->hash.key = base->hash.key;
        ref->obj = base;
        ref->tfile = tfile;
        ref->ref_type = ref_type;
        kref_init(&ref->kref);

        write_lock(&tfile->lock);
        ret = drm_ht_insert_item(ht, &ref->hash);

        if (likely(ret == 0)) {
            list_add_tail(&ref->head, &tfile->ref_list);
            kref_get(&base->refcount);
            write_unlock(&tfile->lock);
            if (existed != NULL)
                *existed = false;
            break;
        }

        write_unlock(&tfile->lock);
        BUG_ON(ret != -EINVAL);

        ttm_mem_global_free(mem_glob, sizeof(*ref));
        kfree(ref);
    }

    return ret;
}
EXPORT_SYMBOL(ttm_ref_object_add);

static void ttm_ref_object_release(struct kref *kref)
{
    struct ttm_ref_object *ref =
        container_of(kref, struct ttm_ref_object, kref);
    struct ttm_base_object *base = ref->obj;
    struct ttm_object_file *tfile = ref->tfile;
    struct drm_open_hash *ht;
    struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;

    ht = &tfile->ref_hash[ref->ref_type];
    (void)drm_ht_remove_item(ht, &ref->hash);
    list_del(&ref->head);
    write_unlock(&tfile->lock);

    if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
        base->ref_obj_release(base, ref->ref_type);

    ttm_base_object_unref(&ref->obj);
    ttm_mem_global_free(mem_glob, sizeof(*ref));
    kfree(ref);
    write_lock(&tfile->lock);
}

int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
                  unsigned long key, enum ttm_ref_type ref_type)
{
    struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
    struct ttm_ref_object *ref;
    struct drm_hash_item *hash;
    int ret;

    write_lock(&tfile->lock);
    ret = drm_ht_find_item(ht, key, &hash);
    if (unlikely(ret != 0)) {
        write_unlock(&tfile->lock);
        return -EINVAL;
    }
    ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
    kref_put(&ref->kref, ttm_ref_object_release);
    write_unlock(&tfile->lock);
    return 0;
}
EXPORT_SYMBOL(ttm_ref_object_base_unref);

void ttm_object_file_release(struct ttm_object_file **p_tfile)
{
    struct ttm_ref_object *ref;
    struct list_head *list;
    unsigned int i;
    struct ttm_object_file *tfile = *p_tfile;

    *p_tfile = NULL;
    write_lock(&tfile->lock);

    /*
     * Since we release the lock within the loop, we have to
     * restart it from the beginning each time.
     */

    while (!list_empty(&tfile->ref_list)) {
        list = tfile->ref_list.next;
        ref = list_entry(list, struct ttm_ref_object, head);
        ttm_ref_object_release(&ref->kref);
    }

    for (i = 0; i < TTM_REF_NUM; ++i)
        drm_ht_remove(&tfile->ref_hash[i]);

    write_unlock(&tfile->lock);
    ttm_object_file_unref(&tfile);
}
EXPORT_SYMBOL(ttm_object_file_release);

struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
                         unsigned int hash_order)
{
    struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
    unsigned int i;
    unsigned int j = 0;
    int ret;

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

    rwlock_init(&tfile->lock);
    tfile->tdev = tdev;
    kref_init(&tfile->refcount);
    INIT_LIST_HEAD(&tfile->ref_list);

    for (i = 0; i < TTM_REF_NUM; ++i) {
        ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
        if (ret) {
            j = i;
            goto out_err;
        }
    }

    return tfile;
out_err:
    for (i = 0; i < j; ++i)
        drm_ht_remove(&tfile->ref_hash[i]);

    kfree(tfile);

    return NULL;
}
EXPORT_SYMBOL(ttm_object_file_init);

struct ttm_object_device *ttm_object_device_init(struct ttm_mem_global
                         *mem_glob,
                         unsigned int hash_order)
{
    struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
    int ret;

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

    tdev->mem_glob = mem_glob;
    rwlock_init(&tdev->object_lock);
    atomic_set(&tdev->object_count, 0);
    ret = drm_ht_create(&tdev->object_hash, hash_order);

    if (likely(ret == 0))
        return tdev;

    kfree(tdev);
    return NULL;
}
EXPORT_SYMBOL(ttm_object_device_init);

void ttm_object_device_release(struct ttm_object_device **p_tdev)
{
    struct ttm_object_device *tdev = *p_tdev;

    *p_tdev = NULL;

    write_lock(&tdev->object_lock);
    drm_ht_remove(&tdev->object_hash);
    write_unlock(&tdev->object_lock);

    kfree(tdev);
}
EXPORT_SYMBOL(ttm_object_device_release);