/**************************************************************************
*
* 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>
*/
/** @file ttm_ref_object.c
*
* Base- and reference object implementation for the various
* ttm objects. Implements reference counting, minimal security checks
* and release on file close.
*/
/**
* struct ttm_object_file
*
* @tdev: Pointer to the ttm_object_device.
*
* @lock: Lock that protects the ref_list list and the
* ref_hash hash tables.
*
* @ref_list: List of ttm_ref_objects to be destroyed at
* file release.
*
* @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
* for fast lookup of ref objects given a base object.
*/
#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>
static inline int __must_check kref_get_unless_zero(struct kref *kref)
{
return atomic_add_unless(&kref->refcount, 1, 0);
}
#define pr_err(fmt, ...) \
printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
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
*
* @object_lock: lock that protects the object_hash hash table.
*
* @object_hash: hash table for fast lookup of object global names.
*
* @object_count: Per device object count.
*
* This is the per-device data structure needed for ttm object management.
*/
struct ttm_object_device {
spinlock_t object_lock;
struct drm_open_hash object_hash;
atomic_t object_count;
struct ttm_mem_global *mem_glob;
};
/**
* struct ttm_ref_object
*
* @hash: Hash entry for the per-file object reference hash.
*
* @head: List entry for the per-file list of ref-objects.
*
* @kref: Ref count.
*
* @obj: Base object this ref object is referencing.
*
* @ref_type: Type of ref object.
*
* This is similar to an idr object, but it also has a hash table entry
* that allows lookup with a pointer to the referenced object as a key. In
* that way, one can easily detect whether a base object is referenced by
* a particular ttm_object_file. It also carries a ref count to avoid creating
* multiple ref objects if a ttm_object_file references the same base
* object more than once.
*/
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;
kref_init(&base->refcount);
spin_lock(&tdev->object_lock);
ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
&base->hash,
(unsigned long)base, 31, 0, 0);
spin_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:
spin_lock(&tdev->object_lock);
(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
spin_unlock(&tdev->object_lock);
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;
spin_lock(&tdev->object_lock);
(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
spin_unlock(&tdev->object_lock);
/*
* Note: We don't use synchronize_rcu() here because it's far
* too slow. It's up to the user to free the object using
* call_rcu() or ttm_base_object_kfree().
*/
if (base->refcount_release) {
ttm_object_file_unref(&base->tfile);
base->refcount_release(&base);
}
}
void ttm_base_object_unref(struct ttm_base_object **p_base)
{
struct ttm_base_object *base = *p_base;
*p_base = NULL;
kref_put(&base->refcount, ttm_release_base);
}
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;
// rcu_read_lock();
ret = drm_ht_find_item_rcu(&tdev->object_hash, key, &hash);
if (likely(ret == 0)) {
base = drm_hash_entry(hash, struct ttm_base_object, hash);
ret = kref_get_unless_zero(&base->refcount) ? 0 : -EINVAL;
}
// rcu_read_unlock();
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;
spin_lock_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;
spin_lock(&tdev->object_lock);
drm_ht_remove(&tdev->object_hash);
spin_unlock(&tdev->object_lock);
kfree(tdev);
}
EXPORT_SYMBOL(ttm_object_device_release);