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