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/hash.h>
36 #include <linux/mm.h>
37 #include <linux/rculist.h>
38 #include <linux/slab.h>
39 #include <linux/vmalloc.h>
40
41 #include <drm/drm_print.h>
42
43 #include "drm_legacy.h"
44
drm_ht_create(struct drm_open_hash * ht,unsigned int order)45 int 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 }
61
drm_ht_verbose_list(struct drm_open_hash * ht,unsigned long key)62 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
63 {
64 struct drm_hash_item *entry;
65 struct hlist_head *h_list;
66 unsigned int hashed_key;
67 int count = 0;
68
69 hashed_key = hash_long(key, ht->order);
70 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
71 h_list = &ht->table[hashed_key];
72 hlist_for_each_entry(entry, h_list, head)
73 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
74 }
75
76 #ifdef notyet
drm_ht_find_key(struct drm_open_hash * ht,unsigned long key)77 static 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 #endif
95
drm_ht_find_key_rcu(struct drm_open_hash * ht,unsigned long key)96 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
97 unsigned long key)
98 {
99 STUB();
100 return NULL;
101 #ifdef notyet
102 struct drm_hash_item *entry;
103 struct hlist_head *h_list;
104 unsigned int hashed_key;
105
106 hashed_key = hash_long(key, ht->order);
107 h_list = &ht->table[hashed_key];
108 hlist_for_each_entry_rcu(entry, h_list, head) {
109 if (entry->key == key)
110 return &entry->head;
111 if (entry->key > key)
112 break;
113 }
114 return NULL;
115 #endif
116 }
117
drm_ht_insert_item(struct drm_open_hash * ht,struct drm_hash_item * item)118 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
119 {
120 STUB();
121 return -ENOSYS;
122 #ifdef notyet
123 struct drm_hash_item *entry;
124 struct hlist_head *h_list;
125 struct hlist_node *parent;
126 unsigned int hashed_key;
127 unsigned long key = item->key;
128
129 hashed_key = hash_long(key, ht->order);
130 h_list = &ht->table[hashed_key];
131 parent = NULL;
132 hlist_for_each_entry(entry, h_list, head) {
133 if (entry->key == key)
134 return -EINVAL;
135 if (entry->key > key)
136 break;
137 parent = &entry->head;
138 }
139 if (parent) {
140 hlist_add_behind_rcu(&item->head, parent);
141 } else {
142 hlist_add_head_rcu(&item->head, h_list);
143 }
144 return 0;
145 #endif
146 }
147
148 /*
149 * Just insert an item and return any "bits" bit key that hasn't been
150 * used before.
151 */
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)152 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
153 unsigned long seed, int bits, int shift,
154 unsigned long add)
155 {
156 int ret;
157 unsigned long mask = (1UL << bits) - 1;
158 unsigned long first, unshifted_key;
159
160 unshifted_key = hash_long(seed, bits);
161 first = unshifted_key;
162 do {
163 item->key = (unshifted_key << shift) + add;
164 ret = drm_ht_insert_item(ht, item);
165 if (ret)
166 unshifted_key = (unshifted_key + 1) & mask;
167 } while(ret && (unshifted_key != first));
168
169 if (ret) {
170 DRM_ERROR("Available key bit space exhausted\n");
171 return -EINVAL;
172 }
173 return 0;
174 }
175
drm_ht_find_item(struct drm_open_hash * ht,unsigned long key,struct drm_hash_item ** item)176 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
177 struct drm_hash_item **item)
178 {
179 struct hlist_node *list;
180
181 list = drm_ht_find_key_rcu(ht, key);
182 if (!list)
183 return -EINVAL;
184
185 *item = hlist_entry(list, struct drm_hash_item, head);
186 return 0;
187 }
188
drm_ht_remove_key(struct drm_open_hash * ht,unsigned long key)189 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
190 {
191 STUB();
192 return -ENOSYS;
193 #ifdef notyet
194 struct hlist_node *list;
195
196 list = drm_ht_find_key(ht, key);
197 if (list) {
198 hlist_del_init_rcu(list);
199 return 0;
200 }
201 return -EINVAL;
202 #endif
203 }
204
drm_ht_remove_item(struct drm_open_hash * ht,struct drm_hash_item * item)205 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
206 {
207 STUB();
208 return -ENOSYS;
209 #ifdef notyet
210 hlist_del_init_rcu(&item->head);
211 return 0;
212 #endif
213 }
214
drm_ht_remove(struct drm_open_hash * ht)215 void drm_ht_remove(struct drm_open_hash *ht)
216 {
217 if (ht->table) {
218 kvfree(ht->table);
219 ht->table = NULL;
220 }
221 }
222