1 /**************************************************************************
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
6 * Permission is hereby granted, free of charge, to any person obtaining a
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11 * permit persons to whom the Software is furnished to do so, subject to
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14 * The above copyright notice and this permission notice (including the
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18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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27 **************************************************************************/
29 * Simple open hash tab implementation.
32 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
36 #include "drm_hashtab.h"
37 #include <linux/hash.h>
40 drm_ht_create(drm_open_hash_t *ht, unsigned int order)
44 ht->size = 1 << order;
47 ht->table = vmalloc(ht->size*sizeof(*ht->table));
49 DRM_ERROR("Out of memory for hash table\n");
52 for (i=0; i< ht->size; ++i) {
53 INIT_HLIST_HEAD(&ht->table[i]);
59 drm_ht_verbose_list(drm_open_hash_t *ht, unsigned long key)
61 drm_hash_item_t *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(list, h_list) {
71 entry = hlist_entry(list, drm_hash_item_t, head);
72 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
76 static struct hlist_node
77 *drm_ht_find_key(drm_open_hash_t *ht, unsigned long key)
79 drm_hash_item_t *entry;
80 struct hlist_head *h_list;
81 struct hlist_node *list;
82 unsigned int hashed_key;
84 hashed_key = hash_long(key, ht->order);
85 h_list = &ht->table[hashed_key];
86 hlist_for_each(list, h_list) {
87 entry = hlist_entry(list, drm_hash_item_t, head);
88 if (entry->key == key)
98 drm_ht_insert_item(drm_open_hash_t *ht, drm_hash_item_t *item)
100 drm_hash_item_t *entry;
101 struct hlist_head *h_list;
102 struct hlist_node *list, *parent;
103 unsigned int hashed_key;
104 unsigned long key = item->key;
106 hashed_key = hash_long(key, ht->order);
107 h_list = &ht->table[hashed_key];
109 hlist_for_each(list, h_list) {
110 entry = hlist_entry(list, drm_hash_item_t, head);
111 if (entry->key == key)
113 if (entry->key > key)
118 hlist_add_after(parent, &item->head);
120 hlist_add_head(&item->head, h_list);
126 * Just insert an item and return any "bits" bit key that hasn't been used before.
130 drm_ht_just_insert_please(drm_open_hash_t *ht, drm_hash_item_t *item,
131 unsigned long seed, int bits, int shift,
135 unsigned long mask = (1 << bits) - 1;
136 unsigned long first, unshifted_key;
138 unshifted_key = hash_long(seed, bits);
139 first = unshifted_key;
141 item->key = (unshifted_key << shift) + add;
142 ret = drm_ht_insert_item(ht, item);
144 unshifted_key = (unshifted_key + 1) & mask;
145 } while(ret && (unshifted_key != first));
148 DRM_ERROR("Available key bit space exhausted\n");
155 drm_ht_find_item(drm_open_hash_t *ht, unsigned long key, drm_hash_item_t **item)
157 struct hlist_node *list;
159 list = drm_ht_find_key(ht, key);
163 *item = hlist_entry(list, drm_hash_item_t, head);
168 drm_ht_remove_key(drm_open_hash_t *ht, unsigned long key)
170 struct hlist_node *list;
172 list = drm_ht_find_key(ht, key);
174 hlist_del_init(list);
182 drm_ht_remove_item(drm_open_hash_t *ht, drm_hash_item_t *item)
184 hlist_del_init(&item->head);
189 void drm_ht_remove(drm_open_hash_t *ht)