1/**************************************************************************
  2 *
  3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
  4 * All Rights Reserved.
  5 *
  6 * Permission is hereby granted, free of charge, to any person obtaining a
  7 * copy of this software and associated documentation files (the
  8 * "Software"), to deal in the Software without restriction, including
  9 * without limitation the rights to use, copy, modify, merge, publish,
 10 * distribute, sub license, and/or sell copies of the Software, and to
 11 * permit persons to whom the Software is furnished to do so, subject to
 12 * the following conditions:
 13 *
 14 * The above copyright notice and this permission notice (including the
 15 * next paragraph) shall be included in all copies or substantial portions
 16 * of the Software.
 17 *
 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 25 *
 26 *
 27 **************************************************************************/
 28/*
 29 * Simple open hash tab implementation.
 30 *
 31 * Authors:
 32 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
 33 */
 34
 35#include <linux/export.h>
 36#include <linux/hash.h>
 37#include <linux/mm.h>
 38#include <linux/rculist.h>
 39#include <linux/slab.h>
 40#include <linux/vmalloc.h>
 41
 42#include <drm/drm_hashtab.h>
 43#include <drm/drm_print.h>
 44
 45int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
 46{
 47	unsigned int size = 1 << order;
 48
 49	ht->order = order;
 50	ht->table = NULL;
 51	if (size <= PAGE_SIZE / sizeof(*ht->table))
 52		ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
 53	else
 54		ht->table = vzalloc(array_size(size, sizeof(*ht->table)));
 55	if (!ht->table) {
 56		DRM_ERROR("Out of memory for hash table\n");
 57		return -ENOMEM;
 58	}
 59	return 0;
 60}
 61EXPORT_SYMBOL(drm_ht_create);
 62
 63void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
 64{
 65	struct drm_hash_item *entry;
 66	struct hlist_head *h_list;
 67	unsigned int hashed_key;
 68	int count = 0;
 69
 70	hashed_key = hash_long(key, ht->order);
 71	DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
 72	h_list = &ht->table[hashed_key];
 73	hlist_for_each_entry(entry, h_list, head)
 74		DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
 75}
 76
 77static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
 78					  unsigned long key)
 79{
 80	struct drm_hash_item *entry;
 81	struct hlist_head *h_list;
 82	unsigned int hashed_key;
 83
 84	hashed_key = hash_long(key, ht->order);
 85	h_list = &ht->table[hashed_key];
 86	hlist_for_each_entry(entry, h_list, head) {
 87		if (entry->key == key)
 88			return &entry->head;
 89		if (entry->key > key)
 90			break;
 91	}
 92	return NULL;
 93}
 94
 95static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
 96					      unsigned long key)
 97{
 98	struct drm_hash_item *entry;
 99	struct hlist_head *h_list;
100	unsigned int hashed_key;
101
102	hashed_key = hash_long(key, ht->order);
103	h_list = &ht->table[hashed_key];
104	hlist_for_each_entry_rcu(entry, h_list, head) {
105		if (entry->key == key)
106			return &entry->head;
107		if (entry->key > key)
108			break;
109	}
110	return NULL;
111}
112
113int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
114{
115	struct drm_hash_item *entry;
116	struct hlist_head *h_list;
117	struct hlist_node *parent;
118	unsigned int hashed_key;
119	unsigned long key = item->key;
120
121	hashed_key = hash_long(key, ht->order);
122	h_list = &ht->table[hashed_key];
123	parent = NULL;
124	hlist_for_each_entry(entry, h_list, head) {
125		if (entry->key == key)
126			return -EINVAL;
127		if (entry->key > key)
128			break;
129		parent = &entry->head;
130	}
131	if (parent) {
132		hlist_add_behind_rcu(&item->head, parent);
133	} else {
134		hlist_add_head_rcu(&item->head, h_list);
135	}
136	return 0;
137}
138EXPORT_SYMBOL(drm_ht_insert_item);
139
140/*
141 * Just insert an item and return any "bits" bit key that hasn't been
142 * used before.
143 */
144int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
145			      unsigned long seed, int bits, int shift,
146			      unsigned long add)
147{
148	int ret;
149	unsigned long mask = (1UL << bits) - 1;
150	unsigned long first, unshifted_key;
151
152	unshifted_key = hash_long(seed, bits);
153	first = unshifted_key;
154	do {
155		item->key = (unshifted_key << shift) + add;
156		ret = drm_ht_insert_item(ht, item);
157		if (ret)
158			unshifted_key = (unshifted_key + 1) & mask;
159	} while(ret && (unshifted_key != first));
160
161	if (ret) {
162		DRM_ERROR("Available key bit space exhausted\n");
163		return -EINVAL;
164	}
165	return 0;
166}
167EXPORT_SYMBOL(drm_ht_just_insert_please);
168
169int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
170		     struct drm_hash_item **item)
171{
172	struct hlist_node *list;
173
174	list = drm_ht_find_key_rcu(ht, key);
175	if (!list)
176		return -EINVAL;
177
178	*item = hlist_entry(list, struct drm_hash_item, head);
179	return 0;
180}
181EXPORT_SYMBOL(drm_ht_find_item);
182
183int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
184{
185	struct hlist_node *list;
186
187	list = drm_ht_find_key(ht, key);
188	if (list) {
189		hlist_del_init_rcu(list);
190		return 0;
191	}
192	return -EINVAL;
193}
194
195int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
196{
197	hlist_del_init_rcu(&item->head);
198	return 0;
199}
200EXPORT_SYMBOL(drm_ht_remove_item);
201
202void drm_ht_remove(struct drm_open_hash *ht)
203{
204	if (ht->table) {
205		kvfree(ht->table);
206		ht->table = NULL;
207	}
208}
209EXPORT_SYMBOL(drm_ht_remove);