Root/drivers/gpu/drm/drm_hashtab.c

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#include <linux/export.h>
40
41int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
42{
43    unsigned int size = 1 << order;
44
45    ht->order = order;
46    ht->table = NULL;
47    if (size <= PAGE_SIZE / sizeof(*ht->table))
48        ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
49    else
50        ht->table = vzalloc(size*sizeof(*ht->table));
51    if (!ht->table) {
52        DRM_ERROR("Out of memory for hash table\n");
53        return -ENOMEM;
54    }
55    return 0;
56}
57EXPORT_SYMBOL(drm_ht_create);
58
59void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
60{
61    struct drm_hash_item *entry;
62    struct hlist_head *h_list;
63    struct hlist_node *list;
64    unsigned int hashed_key;
65    int count = 0;
66
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, struct drm_hash_item, head);
72        DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
73    }
74}
75
76static 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    struct hlist_node *list;
82    unsigned int hashed_key;
83
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, struct drm_hash_item, head);
88        if (entry->key == key)
89            return list;
90        if (entry->key > key)
91            break;
92    }
93    return NULL;
94}
95
96
97int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
98{
99    struct drm_hash_item *entry;
100    struct hlist_head *h_list;
101    struct hlist_node *list, *parent;
102    unsigned int hashed_key;
103    unsigned long key = item->key;
104
105    hashed_key = hash_long(key, ht->order);
106    h_list = &ht->table[hashed_key];
107    parent = NULL;
108    hlist_for_each(list, h_list) {
109        entry = hlist_entry(list, struct drm_hash_item, head);
110        if (entry->key == key)
111            return -EINVAL;
112        if (entry->key > key)
113            break;
114        parent = list;
115    }
116    if (parent) {
117        hlist_add_after(parent, &item->head);
118    } else {
119        hlist_add_head(&item->head, h_list);
120    }
121    return 0;
122}
123EXPORT_SYMBOL(drm_ht_insert_item);
124
125/*
126 * Just insert an item and return any "bits" bit key that hasn't been
127 * used before.
128 */
129int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
130                  unsigned long seed, int bits, int shift,
131                  unsigned long add)
132{
133    int ret;
134    unsigned long mask = (1 << bits) - 1;
135    unsigned long first, unshifted_key;
136
137    unshifted_key = hash_long(seed, bits);
138    first = unshifted_key;
139    do {
140        item->key = (unshifted_key << shift) + add;
141        ret = drm_ht_insert_item(ht, item);
142        if (ret)
143            unshifted_key = (unshifted_key + 1) & mask;
144    } while(ret && (unshifted_key != first));
145
146    if (ret) {
147        DRM_ERROR("Available key bit space exhausted\n");
148        return -EINVAL;
149    }
150    return 0;
151}
152EXPORT_SYMBOL(drm_ht_just_insert_please);
153
154int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
155             struct drm_hash_item **item)
156{
157    struct hlist_node *list;
158
159    list = drm_ht_find_key(ht, key);
160    if (!list)
161        return -EINVAL;
162
163    *item = hlist_entry(list, struct drm_hash_item, head);
164    return 0;
165}
166EXPORT_SYMBOL(drm_ht_find_item);
167
168int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
169{
170    struct hlist_node *list;
171
172    list = drm_ht_find_key(ht, key);
173    if (list) {
174        hlist_del_init(list);
175        return 0;
176    }
177    return -EINVAL;
178}
179
180int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
181{
182    hlist_del_init(&item->head);
183    return 0;
184}
185EXPORT_SYMBOL(drm_ht_remove_item);
186
187void drm_ht_remove(struct drm_open_hash *ht)
188{
189    if (ht->table) {
190        if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order)
191            kfree(ht->table);
192        else
193            vfree(ht->table);
194        ht->table = NULL;
195    }
196}
197EXPORT_SYMBOL(drm_ht_remove);
198

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