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
drm_ht_create(struct drm_open_hash * ht,unsigned int order)41 int 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 = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
51 if (!ht->table) {
52 DRM_ERROR("Out of memory for hash table\n");
53 return -ENOMEM;
54 }
55 return 0;
56 }
57 EXPORT_SYMBOL(drm_ht_create);
58
drm_ht_verbose_list(struct drm_open_hash * ht,unsigned long key)59 void 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
drm_ht_find_key(struct drm_open_hash * ht,unsigned long key)73 static 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
drm_ht_find_key_rcu(struct drm_open_hash * ht,unsigned long key)91 static 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
drm_ht_insert_item(struct drm_open_hash * ht,struct drm_hash_item * item)109 int 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 }
134 EXPORT_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 */
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)140 int 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 = (1UL << 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 }
163 EXPORT_SYMBOL(drm_ht_just_insert_please);
164
drm_ht_find_item(struct drm_open_hash * ht,unsigned long key,struct drm_hash_item ** item)165 int 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 }
177 EXPORT_SYMBOL(drm_ht_find_item);
178
drm_ht_remove_key(struct drm_open_hash * ht,unsigned long key)179 int 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
drm_ht_remove_item(struct drm_open_hash * ht,struct drm_hash_item * item)191 int 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 }
196 EXPORT_SYMBOL(drm_ht_remove_item);
197
drm_ht_remove(struct drm_open_hash * ht)198 void drm_ht_remove(struct drm_open_hash *ht)
199 {
200 if (ht->table) {
201 if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order)
202 kfree(ht->table);
203 else
204 kfree(ht->table);
205 ht->table = NULL;
206 }
207 }
208 EXPORT_SYMBOL(drm_ht_remove);
209