1 /**************************************************************************
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
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:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
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.
27 **************************************************************************/
29 * Simple open hash tab implementation.
32 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
36 #include <drm/drm_hashtab.h>
37 #include <linux/hash.h>
38 #include <linux/slab.h>
39 #include <linux/export.h>
41 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
43 unsigned int size = 1 << order;
47 if (size <= PAGE_SIZE / sizeof(*ht->table))
48 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
50 ht->table = vzalloc(size*sizeof(*ht->table));
52 DRM_ERROR("Out of memory for hash table\n");
57 EXPORT_SYMBOL(drm_ht_create);
59 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
61 struct drm_hash_item *entry;
62 struct hlist_head *h_list;
63 struct hlist_node *list;
64 unsigned int hashed_key;
67 hashed_key = hash_long(key, ht->order);
68 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
69 h_list = &ht->table[hashed_key];
70 hlist_for_each_entry(entry, list, h_list, head)
71 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
74 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
77 struct drm_hash_item *entry;
78 struct hlist_head *h_list;
79 struct hlist_node *list;
80 unsigned int hashed_key;
82 hashed_key = hash_long(key, ht->order);
83 h_list = &ht->table[hashed_key];
84 hlist_for_each_entry(entry, list, h_list, head) {
85 if (entry->key == key)
93 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
96 struct drm_hash_item *entry;
97 struct hlist_head *h_list;
98 struct hlist_node *list;
99 unsigned int hashed_key;
101 hashed_key = hash_long(key, ht->order);
102 h_list = &ht->table[hashed_key];
103 hlist_for_each_entry_rcu(entry, list, h_list, head) {
104 if (entry->key == key)
106 if (entry->key > key)
112 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
114 struct drm_hash_item *entry;
115 struct hlist_head *h_list;
116 struct hlist_node *list, *parent;
117 unsigned int hashed_key;
118 unsigned long key = item->key;
120 hashed_key = hash_long(key, ht->order);
121 h_list = &ht->table[hashed_key];
123 hlist_for_each_entry(entry, list, h_list, head) {
124 if (entry->key == key)
126 if (entry->key > key)
131 hlist_add_after_rcu(parent, &item->head);
133 hlist_add_head_rcu(&item->head, h_list);
137 EXPORT_SYMBOL(drm_ht_insert_item);
140 * Just insert an item and return any "bits" bit key that hasn't been
143 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
144 unsigned long seed, int bits, int shift,
148 unsigned long mask = (1 << bits) - 1;
149 unsigned long first, unshifted_key;
151 unshifted_key = hash_long(seed, bits);
152 first = unshifted_key;
154 item->key = (unshifted_key << shift) + add;
155 ret = drm_ht_insert_item(ht, item);
157 unshifted_key = (unshifted_key + 1) & mask;
158 } while(ret && (unshifted_key != first));
161 DRM_ERROR("Available key bit space exhausted\n");
166 EXPORT_SYMBOL(drm_ht_just_insert_please);
168 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
169 struct drm_hash_item **item)
171 struct hlist_node *list;
173 list = drm_ht_find_key_rcu(ht, key);
177 *item = hlist_entry(list, struct drm_hash_item, head);
180 EXPORT_SYMBOL(drm_ht_find_item);
182 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
184 struct hlist_node *list;
186 list = drm_ht_find_key(ht, key);
188 hlist_del_init_rcu(list);
194 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
196 hlist_del_init_rcu(&item->head);
199 EXPORT_SYMBOL(drm_ht_remove_item);
201 void drm_ht_remove(struct drm_open_hash *ht)
204 if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order)
211 EXPORT_SYMBOL(drm_ht_remove);