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 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: drm_hashtab.c,v 1.1 2011/02/18 14:26:09 jmcneill Exp $");
31
32 /*
33 * Simple open hash tab implementation.
34 *
35 * Authors:
36 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
37 */
38
39 #include "drmP.h"
40 #include "drm_hashtab.h"
41
42 #include <sys/hash.h>
43
drm_ht_create(struct drm_open_hash * ht,unsigned int order)44 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
45 {
46 ht->size = 1 << order;
47 ht->order = order;
48 ht->table = NULL;
49 ht->table = hashinit(ht->size, HASH_LIST, false, &ht->mask);
50 if (!ht->table) {
51 DRM_ERROR("Out of memory for hash table\n");
52 return -ENOMEM;
53 }
54 return 0;
55 }
56
drm_ht_verbose_list(struct drm_open_hash * ht,unsigned long key)57 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
58 {
59 struct drm_hash_item *entry;
60 struct drm_hash_item_list *h_list;
61 unsigned int hashed_key;
62 int count = 0;
63
64 hashed_key = hash32_buf(&key, sizeof(key), ht->order);
65 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
66 h_list = &ht->table[hashed_key & ht->mask];
67 LIST_FOREACH(entry, h_list, head)
68 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
69 }
70
71 static struct drm_hash_item *
drm_ht_find_key(struct drm_open_hash * ht,unsigned long key)72 drm_ht_find_key(struct drm_open_hash *ht, unsigned long key)
73 {
74 struct drm_hash_item *entry;
75 struct drm_hash_item_list *h_list;
76 unsigned int hashed_key;
77
78 hashed_key = hash32_buf(&key, sizeof(key), ht->order);
79 h_list = &ht->table[hashed_key & ht->mask];
80 LIST_FOREACH(entry, h_list, head) {
81 if (entry->key == key)
82 return entry;
83 if (entry->key > key)
84 break;
85 }
86 return NULL;
87 }
88
89
drm_ht_insert_item(struct drm_open_hash * ht,struct drm_hash_item * item)90 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
91 {
92 struct drm_hash_item *entry, *parent;
93 struct drm_hash_item_list *h_list;
94 unsigned int hashed_key;
95 unsigned long key = item->key;
96
97 hashed_key = hash32_buf(&key, sizeof(key), ht->order);
98 h_list = &ht->table[hashed_key & ht->mask];
99 parent = NULL;
100 LIST_FOREACH(entry, h_list, head) {
101 if (entry->key == key)
102 return -EINVAL;
103 if (entry->key > key)
104 break;
105 parent = entry;
106 }
107 if (parent) {
108 LIST_INSERT_AFTER(parent, item, head);
109 } else {
110 LIST_INSERT_HEAD(h_list, item, head);
111 }
112 return 0;
113 }
114
115 /*
116 * Just insert an item and return any "bits" bit key that hasn't been
117 * used before.
118 */
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)119 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
120 unsigned long seed, int bits, int shift,
121 unsigned long add)
122 {
123 int ret;
124 unsigned long mask = (1 << bits) - 1;
125 unsigned long first, unshifted_key = 0;
126
127 unshifted_key = hash32_buf(&seed, sizeof(seed), unshifted_key);
128 first = unshifted_key;
129 do {
130 item->key = (unshifted_key << shift) + add;
131 ret = drm_ht_insert_item(ht, item);
132 if (ret)
133 unshifted_key = (unshifted_key + 1) & mask;
134 } while(ret && (unshifted_key != first));
135
136 if (ret) {
137 DRM_ERROR("Available key bit space exhausted\n");
138 return -EINVAL;
139 }
140 return 0;
141 }
142
drm_ht_find_item(struct drm_open_hash * ht,unsigned long key,struct drm_hash_item ** item)143 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
144 struct drm_hash_item **item)
145 {
146 struct drm_hash_item *entry;
147
148 entry = drm_ht_find_key(ht, key);
149 if (!entry)
150 return -EINVAL;
151
152 *item = entry;
153 return 0;
154 }
155
drm_ht_remove_key(struct drm_open_hash * ht,unsigned long key)156 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
157 {
158 struct drm_hash_item *entry;
159
160 entry = drm_ht_find_key(ht, key);
161 if (entry) {
162 LIST_REMOVE(entry, head);
163 return 0;
164 }
165 return -EINVAL;
166 }
167
drm_ht_remove_item(struct drm_open_hash * ht,struct drm_hash_item * item)168 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
169 {
170 LIST_REMOVE(item, head);
171 return 0;
172 }
173
drm_ht_remove(struct drm_open_hash * ht)174 void drm_ht_remove(struct drm_open_hash *ht)
175 {
176 if (ht->table) {
177 hashdone(ht->table, HASH_LIST, ht->mask);
178 ht->table = NULL;
179 }
180 }
181