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
drm_ht_find_key(struct drm_open_hash * ht,unsigned long key)76 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
77 unsigned long key)
78 {
79 struct drm_hash_item *entry;
80 struct hlist_head *h_list;
81 unsigned int hashed_key;
82
83 hashed_key = hash_long(key, ht->order);
84 h_list = &ht->table[hashed_key];
85 hlist_for_each_entry(entry, h_list, head) {
86 if (entry->key == key)
87 return &entry->head;
88 if (entry->key > key)
89 break;
90 }
91 return NULL;
92 }
93
drm_ht_find_key_rcu(struct drm_open_hash * ht,unsigned long key)94 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
95 unsigned long key)
96 {
97 struct drm_hash_item *entry;
98 struct hlist_head *h_list;
99 unsigned int hashed_key;
100
101 hashed_key = hash_long(key, ht->order);
102 h_list = &ht->table[hashed_key];
103 hlist_for_each_entry_rcu(entry, h_list, head) {
104 if (entry->key == key)
105 return &entry->head;
106 if (entry->key > key)
107 break;
108 }
109 return NULL;
110 }
111
drm_ht_insert_item(struct drm_open_hash * ht,struct drm_hash_item * item)112 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
113 {
114 struct drm_hash_item *entry;
115 struct hlist_head *h_list;
116 struct hlist_node *parent;
117 unsigned int hashed_key;
118 unsigned long key = item->key;
119
120 hashed_key = hash_long(key, ht->order);
121 h_list = &ht->table[hashed_key];
122 parent = NULL;
123 hlist_for_each_entry(entry, h_list, head) {
124 if (entry->key == key)
125 return -EINVAL;
126 if (entry->key > key)
127 break;
128 parent = &entry->head;
129 }
130 if (parent) {
131 hlist_add_behind_rcu(&item->head, parent);
132 } else {
133 hlist_add_head_rcu(&item->head, h_list);
134 }
135 return 0;
136 }
137
138 /*
139 * Just insert an item and return any "bits" bit key that hasn't been
140 * used before.
141 */
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)142 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
143 unsigned long seed, int bits, int shift,
144 unsigned long add)
145 {
146 int ret;
147 unsigned long mask = (1UL << bits) - 1;
148 unsigned long first, unshifted_key;
149
150 unshifted_key = hash_long(seed, bits);
151 first = unshifted_key;
152 do {
153 item->key = (unshifted_key << shift) + add;
154 ret = drm_ht_insert_item(ht, item);
155 if (ret)
156 unshifted_key = (unshifted_key + 1) & mask;
157 } while(ret && (unshifted_key != first));
158
159 if (ret) {
160 DRM_ERROR("Available key bit space exhausted\n");
161 return -EINVAL;
162 }
163 return 0;
164 }
165
drm_ht_find_item(struct drm_open_hash * ht,unsigned long key,struct drm_hash_item ** item)166 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
167 struct drm_hash_item **item)
168 {
169 struct hlist_node *list;
170
171 list = drm_ht_find_key_rcu(ht, key);
172 if (!list)
173 return -EINVAL;
174
175 *item = hlist_entry(list, struct drm_hash_item, head);
176 return 0;
177 }
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
drm_ht_remove(struct drm_open_hash * ht)197 void drm_ht_remove(struct drm_open_hash *ht)
198 {
199 if (ht->table) {
200 kvfree(ht->table);
201 ht->table = NULL;
202 }
203 }
204