/**************************************************************************
*
* Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. 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.
*
*
**************************************************************************/
/*
* Simple open hash tab implementation.
*
* Authors:
* Thomas Hellström <thomas-at-tungstengraphics-dot-com>
*/
#include <drm/drmP.h>
#include <drm/drm_hashtab.h>
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/rculist.h>
#define hlist_for_each_entry_rcu(pos, head, member) \
for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\
typeof(*(pos)), member); \
pos; \
pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
&(pos)->member)), typeof(*(pos)), member))
int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
{
unsigned int size = 1 << order;
ht->order = order;
ht->table = NULL;
ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
if (!ht->table) {
DRM_ERROR("Out of memory for hash table\n");
return -ENOMEM;
}
return 0;
}
EXPORT_SYMBOL(drm_ht_create);
void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
{
struct drm_hash_item *entry;
struct hlist_head *h_list;
unsigned int hashed_key;
int count = 0;
hashed_key = hash_long(key, ht->order);
DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
h_list = &ht->table[hashed_key];
hlist_for_each_entry(entry, h_list, head)
DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
}
static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
unsigned long key)
{
struct drm_hash_item *entry;
struct hlist_head *h_list;
unsigned int hashed_key;
hashed_key = hash_long(key, ht->order);
h_list = &ht->table[hashed_key];
hlist_for_each_entry(entry, h_list, head) {
if (entry->key == key)
return &entry->head;
if (entry->key > key)
break;
}
return NULL;
}
static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
unsigned long key)
{
struct drm_hash_item *entry;
struct hlist_head *h_list;
unsigned int hashed_key;
hashed_key = hash_long(key, ht->order);
h_list = &ht->table[hashed_key];
hlist_for_each_entry_rcu(entry, h_list, head) {
if (entry->key == key)
return &entry->head;
if (entry->key > key)
break;
}
return NULL;
}
int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
{
struct drm_hash_item *entry;
struct hlist_head *h_list;
struct hlist_node *parent;
unsigned int hashed_key;
unsigned long key = item->key;
hashed_key = hash_long(key, ht->order);
h_list = &ht->table[hashed_key];
parent = NULL;
hlist_for_each_entry(entry, h_list, head) {
if (entry->key == key)
return -EINVAL;
if (entry->key > key)
break;
parent = &entry->head;
}
if (parent) {
hlist_add_after_rcu(parent, &item->head);
} else {
hlist_add_head_rcu(&item->head, h_list);
}
return 0;
}
EXPORT_SYMBOL(drm_ht_insert_item);
/*
* Just insert an item and return any "bits" bit key that hasn't been
* used before.
*/
int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
unsigned long seed, int bits, int shift,
unsigned long add)
{
int ret;
unsigned long mask = (1 << bits) - 1;
unsigned long first, unshifted_key;
unshifted_key = hash_long(seed, bits);
first = unshifted_key;
do {
item->key = (unshifted_key << shift) + add;
ret = drm_ht_insert_item(ht, item);
if (ret)
unshifted_key = (unshifted_key + 1) & mask;
} while(ret && (unshifted_key != first));
if (ret) {
DRM_ERROR("Available key bit space exhausted\n");
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL(drm_ht_just_insert_please);
int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
struct drm_hash_item **item)
{
struct hlist_node *list;
list = drm_ht_find_key_rcu(ht, key);
if (!list)
return -EINVAL;
*item = hlist_entry(list, struct drm_hash_item, head);
return 0;
}
EXPORT_SYMBOL(drm_ht_find_item);
int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
{
struct hlist_node *list;
list = drm_ht_find_key(ht, key);
if (list) {
hlist_del_init_rcu(list);
return 0;
}
return -EINVAL;
}
int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
{
hlist_del_init_rcu(&item->head);
return 0;
}
EXPORT_SYMBOL(drm_ht_remove_item);
void drm_ht_remove(struct drm_open_hash *ht)
{
if (ht->table) {
kfree(ht->table);
ht->table = NULL;
}
}
EXPORT_SYMBOL(drm_ht_remove);