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 | |
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(n: size, 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 | |
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 | 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 | |
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 | |
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(n: &item->head, prev: parent); |
132 | } else { |
133 | hlist_add_head_rcu(n: &item->head, h: 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 | */ |
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 | |
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 | |
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(n: list); |
186 | return 0; |
187 | } |
188 | return -EINVAL; |
189 | } |
190 | |
191 | int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) |
192 | { |
193 | hlist_del_init_rcu(n: &item->head); |
194 | return 0; |
195 | } |
196 | |
197 | void drm_ht_remove(struct drm_open_hash *ht) |
198 | { |
199 | if (ht->table) { |
200 | kvfree(addr: ht->table); |
201 | ht->table = NULL; |
202 | } |
203 | } |
204 | |