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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 "drmP.h" | |
36 | #include "drm_hashtab.h" | |
37 | #include <linux/hash.h> | |
38 | #include <linux/slab.h> | |
39 | ||
40 | int drm_ht_create(struct drm_open_hash *ht, unsigned int order) | |
41 | { | |
42 | unsigned int size = 1 << order; | |
43 | ||
44 | ht->order = order; | |
45 | ht->table = NULL; | |
46 | if (size <= PAGE_SIZE / sizeof(*ht->table)) | |
47 | ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL); | |
48 | else | |
49 | ht->table = vzalloc(size*sizeof(*ht->table)); | |
50 | if (!ht->table) { | |
51 | DRM_ERROR("Out of memory for hash table\n"); | |
52 | return -ENOMEM; | |
53 | } | |
54 | return 0; | |
55 | } | |
56 | EXPORT_SYMBOL(drm_ht_create); | |
57 | ||
58 | void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) | |
59 | { | |
60 | struct drm_hash_item *entry; | |
61 | struct hlist_head *h_list; | |
62 | struct hlist_node *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(list, h_list) { | |
70 | entry = hlist_entry(list, struct drm_hash_item, head); | |
71 | DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); | |
72 | } | |
73 | } | |
74 | ||
75 | static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, | |
76 | unsigned long key) | |
77 | { | |
78 | struct drm_hash_item *entry; | |
79 | struct hlist_head *h_list; | |
80 | struct hlist_node *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(list, h_list) { | |
86 | entry = hlist_entry(list, struct drm_hash_item, head); | |
87 | if (entry->key == key) | |
88 | return list; | |
89 | if (entry->key > key) | |
90 | break; | |
91 | } | |
92 | return NULL; | |
93 | } | |
94 | ||
95 | ||
96 | int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) | |
97 | { | |
98 | struct drm_hash_item *entry; | |
99 | struct hlist_head *h_list; | |
100 | struct hlist_node *list, *parent; | |
101 | unsigned int hashed_key; | |
102 | unsigned long key = item->key; | |
103 | ||
104 | hashed_key = hash_long(key, ht->order); | |
105 | h_list = &ht->table[hashed_key]; | |
106 | parent = NULL; | |
107 | hlist_for_each(list, h_list) { | |
108 | entry = hlist_entry(list, struct drm_hash_item, head); | |
109 | if (entry->key == key) | |
110 | return -EINVAL; | |
111 | if (entry->key > key) | |
112 | break; | |
113 | parent = list; | |
114 | } | |
115 | if (parent) { | |
116 | hlist_add_after(parent, &item->head); | |
117 | } else { | |
118 | hlist_add_head(&item->head, h_list); | |
119 | } | |
120 | return 0; | |
121 | } | |
122 | EXPORT_SYMBOL(drm_ht_insert_item); | |
123 | ||
124 | /* | |
125 | * Just insert an item and return any "bits" bit key that hasn't been | |
126 | * used before. | |
127 | */ | |
128 | int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, | |
129 | unsigned long seed, int bits, int shift, | |
130 | unsigned long add) | |
131 | { | |
132 | int ret; | |
133 | unsigned long mask = (1 << bits) - 1; | |
134 | unsigned long first, unshifted_key; | |
135 | ||
136 | unshifted_key = hash_long(seed, bits); | |
137 | first = unshifted_key; | |
138 | do { | |
139 | item->key = (unshifted_key << shift) + add; | |
140 | ret = drm_ht_insert_item(ht, item); | |
141 | if (ret) | |
142 | unshifted_key = (unshifted_key + 1) & mask; | |
143 | } while(ret && (unshifted_key != first)); | |
144 | ||
145 | if (ret) { | |
146 | DRM_ERROR("Available key bit space exhausted\n"); | |
147 | return -EINVAL; | |
148 | } | |
149 | return 0; | |
150 | } | |
151 | EXPORT_SYMBOL(drm_ht_just_insert_please); | |
152 | ||
153 | int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, | |
154 | struct drm_hash_item **item) | |
155 | { | |
156 | struct hlist_node *list; | |
157 | ||
158 | list = drm_ht_find_key(ht, key); | |
159 | if (!list) | |
160 | return -EINVAL; | |
161 | ||
162 | *item = hlist_entry(list, struct drm_hash_item, head); | |
163 | return 0; | |
164 | } | |
165 | EXPORT_SYMBOL(drm_ht_find_item); | |
166 | ||
167 | int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) | |
168 | { | |
169 | struct hlist_node *list; | |
170 | ||
171 | list = drm_ht_find_key(ht, key); | |
172 | if (list) { | |
173 | hlist_del_init(list); | |
174 | return 0; | |
175 | } | |
176 | return -EINVAL; | |
177 | } | |
178 | ||
179 | int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) | |
180 | { | |
181 | hlist_del_init(&item->head); | |
182 | return 0; | |
183 | } | |
184 | EXPORT_SYMBOL(drm_ht_remove_item); | |
185 | ||
186 | void drm_ht_remove(struct drm_open_hash *ht) | |
187 | { | |
188 | if (ht->table) { | |
189 | if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order) | |
190 | kfree(ht->table); | |
191 | else | |
192 | vfree(ht->table); | |
193 | ht->table = NULL; | |
194 | } | |
195 | } | |
196 | EXPORT_SYMBOL(drm_ht_remove); |