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 <drm/drmP.h>
 36#include <drm/drm_hashtab.h>
 37#include <linux/hash.h>
 38#include <linux/slab.h>
 39#include <linux/export.h>
 40
 41int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
 42{
 43	unsigned int size = 1 << order;
 44
 45	ht->order = order;
 46	ht->table = NULL;
 47	if (size <= PAGE_SIZE / sizeof(*ht->table))
 48		ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
 49	else
 50		ht->table = vzalloc(size*sizeof(*ht->table));
 51	if (!ht->table) {
 52		DRM_ERROR("Out of memory for hash table\n");
 53		return -ENOMEM;
 54	}
 55	return 0;
 56}
 57EXPORT_SYMBOL(drm_ht_create);
 58
 59void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
 60{
 61	struct drm_hash_item *entry;
 62	struct hlist_head *h_list;
 63	unsigned int hashed_key;
 64	int count = 0;
 65
 66	hashed_key = hash_long(key, ht->order);
 67	DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
 68	h_list = &ht->table[hashed_key];
 69	hlist_for_each_entry(entry, h_list, head)
 70		DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
 71}
 72
 73static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
 74					  unsigned long key)
 75{
 76	struct drm_hash_item *entry;
 77	struct hlist_head *h_list;
 78	unsigned int hashed_key;
 79
 80	hashed_key = hash_long(key, ht->order);
 81	h_list = &ht->table[hashed_key];
 82	hlist_for_each_entry(entry, h_list, head) {
 83		if (entry->key == key)
 84			return &entry->head;
 85		if (entry->key > key)
 86			break;
 87	}
 88	return NULL;
 89}
 90
 91static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
 92					      unsigned long key)
 93{
 94	struct drm_hash_item *entry;
 95	struct hlist_head *h_list;
 96	unsigned int hashed_key;
 97
 98	hashed_key = hash_long(key, ht->order);
 99	h_list = &ht->table[hashed_key];
100	hlist_for_each_entry_rcu(entry, h_list, head) {
101		if (entry->key == key)
102			return &entry->head;
103		if (entry->key > key)
104			break;
105	}
106	return NULL;
107}
108
109int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
110{
111	struct drm_hash_item *entry;
112	struct hlist_head *h_list;
113	struct hlist_node *parent;
114	unsigned int hashed_key;
115	unsigned long key = item->key;
116
117	hashed_key = hash_long(key, ht->order);
118	h_list = &ht->table[hashed_key];
119	parent = NULL;
120	hlist_for_each_entry(entry, h_list, head) {
121		if (entry->key == key)
122			return -EINVAL;
123		if (entry->key > key)
124			break;
125		parent = &entry->head;
126	}
127	if (parent) {
128		hlist_add_behind_rcu(&item->head, parent);
129	} else {
130		hlist_add_head_rcu(&item->head, h_list);
131	}
132	return 0;
133}
134EXPORT_SYMBOL(drm_ht_insert_item);
135
136/*
137 * Just insert an item and return any "bits" bit key that hasn't been
138 * used before.
139 */
140int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
141			      unsigned long seed, int bits, int shift,
142			      unsigned long add)
143{
144	int ret;
145	unsigned long mask = (1 << bits) - 1;
146	unsigned long first, unshifted_key;
147
148	unshifted_key = hash_long(seed, bits);
149	first = unshifted_key;
150	do {
151		item->key = (unshifted_key << shift) + add;
152		ret = drm_ht_insert_item(ht, item);
153		if (ret)
154			unshifted_key = (unshifted_key + 1) & mask;
155	} while(ret && (unshifted_key != first));
156
157	if (ret) {
158		DRM_ERROR("Available key bit space exhausted\n");
159		return -EINVAL;
160	}
161	return 0;
162}
163EXPORT_SYMBOL(drm_ht_just_insert_please);
164
165int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
166		     struct drm_hash_item **item)
167{
168	struct hlist_node *list;
169
170	list = drm_ht_find_key_rcu(ht, key);
171	if (!list)
172		return -EINVAL;
173
174	*item = hlist_entry(list, struct drm_hash_item, head);
175	return 0;
176}
177EXPORT_SYMBOL(drm_ht_find_item);
178
179int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
180{
181	struct hlist_node *list;
182
183	list = drm_ht_find_key(ht, key);
184	if (list) {
185		hlist_del_init_rcu(list);
186		return 0;
187	}
188	return -EINVAL;
189}
190
191int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
192{
193	hlist_del_init_rcu(&item->head);
194	return 0;
195}
196EXPORT_SYMBOL(drm_ht_remove_item);
197
198void drm_ht_remove(struct drm_open_hash *ht)
199{
200	if (ht->table) {
201		kvfree(ht->table);
202		ht->table = NULL;
203	}
204}
205EXPORT_SYMBOL(drm_ht_remove);