1 /* $NetBSD: drm_hashtab.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $ */
2
3 /**************************************************************************
4 *
5 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
6 * All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the
10 * "Software"), to deal in the Software without restriction, including
11 * without limitation the rights to use, copy, modify, merge, publish,
12 * distribute, sub license, and/or sell copies of the Software, and to
13 * permit persons to whom the Software is furnished to do so, subject to
14 * the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the
17 * next paragraph) shall be included in all copies or substantial portions
18 * of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
23 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
24 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
25 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
26 * USE OR OTHER DEALINGS IN THE SOFTWARE.
27 *
28 *
29 **************************************************************************/
30 /*
31 * Simple open hash tab implementation.
32 *
33 * Authors:
34 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
35 */
36
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: drm_hashtab.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $");
39
40 #include <linux/export.h>
41 #include <linux/hash.h>
42 #include <linux/mm.h>
43 #include <linux/rculist.h>
44 #include <linux/slab.h>
45 #include <linux/vmalloc.h>
46
47 #include <drm/drm_hashtab.h>
48 #include <drm/drm_print.h>
49
drm_ht_create(struct drm_open_hash * ht,unsigned int order)50 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
51 {
52 unsigned int size = 1 << order;
53
54 ht->order = order;
55 ht->table = NULL;
56 if (size <= PAGE_SIZE / sizeof(*ht->table))
57 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
58 else
59 ht->table = vzalloc(array_size(size, sizeof(*ht->table)));
60 if (!ht->table) {
61 DRM_ERROR("Out of memory for hash table\n");
62 return -ENOMEM;
63 }
64 return 0;
65 }
66 EXPORT_SYMBOL(drm_ht_create);
67
drm_ht_verbose_list(struct drm_open_hash * ht,unsigned long key)68 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
69 {
70 struct drm_hash_item *entry;
71 struct hlist_head *h_list;
72 unsigned int hashed_key;
73 int count = 0;
74
75 hashed_key = hash_long(key, ht->order);
76 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
77 h_list = &ht->table[hashed_key];
78 hlist_for_each_entry(entry, h_list, head)
79 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
80 }
81
drm_ht_find_key(struct drm_open_hash * ht,unsigned long key)82 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
83 unsigned long key)
84 {
85 struct drm_hash_item *entry;
86 struct hlist_head *h_list;
87 unsigned int hashed_key;
88
89 hashed_key = hash_long(key, ht->order);
90 h_list = &ht->table[hashed_key];
91 hlist_for_each_entry(entry, h_list, head) {
92 if (entry->key == key)
93 return &entry->head;
94 if (entry->key > key)
95 break;
96 }
97 return NULL;
98 }
99
drm_ht_find_key_rcu(struct drm_open_hash * ht,unsigned long key)100 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
101 unsigned long key)
102 {
103 struct drm_hash_item *entry;
104 struct hlist_head *h_list;
105 unsigned int hashed_key;
106
107 hashed_key = hash_long(key, ht->order);
108 h_list = &ht->table[hashed_key];
109 hlist_for_each_entry_rcu(entry, h_list, head) {
110 if (entry->key == key)
111 return &entry->head;
112 if (entry->key > key)
113 break;
114 }
115 return NULL;
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 struct drm_hash_item *entry;
121 struct hlist_head *h_list;
122 struct hlist_node *parent;
123 unsigned int hashed_key;
124 unsigned long key = item->key;
125
126 hashed_key = hash_long(key, ht->order);
127 h_list = &ht->table[hashed_key];
128 parent = NULL;
129 hlist_for_each_entry(entry, h_list, head) {
130 if (entry->key == key)
131 return -EINVAL;
132 if (entry->key > key)
133 break;
134 parent = &entry->head;
135 }
136 if (parent) {
137 hlist_add_behind_rcu(&item->head, parent);
138 } else {
139 hlist_add_head_rcu(&item->head, h_list);
140 }
141 return 0;
142 }
143 EXPORT_SYMBOL(drm_ht_insert_item);
144
145 /*
146 * Just insert an item and return any "bits" bit key that hasn't been
147 * used before.
148 */
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)149 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
150 unsigned long seed, int bits, int shift,
151 unsigned long add)
152 {
153 int ret;
154 unsigned long mask = (1UL << bits) - 1;
155 unsigned long first, unshifted_key;
156
157 unshifted_key = hash_long(seed, bits);
158 first = unshifted_key;
159 do {
160 item->key = (unshifted_key << shift) + add;
161 ret = drm_ht_insert_item(ht, item);
162 if (ret)
163 unshifted_key = (unshifted_key + 1) & mask;
164 } while(ret && (unshifted_key != first));
165
166 if (ret) {
167 DRM_ERROR("Available key bit space exhausted\n");
168 return -EINVAL;
169 }
170 return 0;
171 }
172 EXPORT_SYMBOL(drm_ht_just_insert_please);
173
drm_ht_find_item(struct drm_open_hash * ht,unsigned long key,struct drm_hash_item ** item)174 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
175 struct drm_hash_item **item)
176 {
177 struct hlist_node *list;
178
179 list = drm_ht_find_key_rcu(ht, key);
180 if (!list)
181 return -EINVAL;
182
183 *item = hlist_entry(list, struct drm_hash_item, head);
184 return 0;
185 }
186 EXPORT_SYMBOL(drm_ht_find_item);
187
drm_ht_remove_key(struct drm_open_hash * ht,unsigned long key)188 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
189 {
190 struct hlist_node *list;
191
192 list = drm_ht_find_key(ht, key);
193 if (list) {
194 hlist_del_init_rcu(list);
195 return 0;
196 }
197 return -EINVAL;
198 }
199
drm_ht_remove_item(struct drm_open_hash * ht,struct drm_hash_item * item)200 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
201 {
202 hlist_del_init_rcu(&item->head);
203 return 0;
204 }
205 EXPORT_SYMBOL(drm_ht_remove_item);
206
drm_ht_remove(struct drm_open_hash * ht)207 void drm_ht_remove(struct drm_open_hash *ht)
208 {
209 if (ht->table) {
210 kvfree(ht->table);
211 ht->table = NULL;
212 }
213 }
214 EXPORT_SYMBOL(drm_ht_remove);
215