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
  40 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
  41 {
  42         unsigned int i;
  43
  44         ht->size = 1 << order;
  45         ht->order = order;
  46         ht->fill = 0;
  47         ht->table = NULL;
  48         ht->use_vmalloc = ((ht->size * sizeof(*ht->table)) > PAGE_SIZE);
  49         if (!ht->use_vmalloc) {
  50                 ht->table = kcalloc(ht->size, sizeof(*ht->table), GFP_KERNEL);
  51         }
  52         if (!ht->table) {
  53                 ht->use_vmalloc = 1;
  54                 ht->table = vmalloc(ht->size*sizeof(*ht->table));
  55         }
  56         if (!ht->table) {
  57                 DRM_ERROR("Out of memory for hash table\n");
  58                 return -ENOMEM;
  59         }
  60         for (i=0; i< ht->size; ++i) {
  61                 INIT_HLIST_HEAD(&ht->table[i]);
  62         }
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(drm_ht_create);
  66
  67 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
  68 {
  69         struct drm_hash_item *entry;
  70         struct hlist_head *h_list;
  71         struct hlist_node *list;
  72         unsigned int hashed_key;
  73         int count = 0;
  74
  75         hashed_key = hash_long(key, ht->order);
  76         DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
  77         h_list = &ht->table[hashed_key];
  78         hlist_for_each(list, h_list) {
  79                 entry = hlist_entry(list, struct drm_hash_item, head);
  80                 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
  81         }
  82 }
  83
  84 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
  85                                           unsigned long key)
  86 {
  87         struct drm_hash_item *entry;
  88         struct hlist_head *h_list;
  89         struct hlist_node *list;
  90         unsigned int hashed_key;
  91
  92         hashed_key = hash_long(key, ht->order);
  93         h_list = &ht->table[hashed_key];
  94         hlist_for_each(list, h_list) {
  95                 entry = hlist_entry(list, struct drm_hash_item, head);
  96                 if (entry->key == key)
  97                         return list;
  98                 if (entry->key > key)
  99                         break;
 100         }
 101         return NULL;
 102 }
 103
 104
 105 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 106 {
 107         struct drm_hash_item *entry;
 108         struct hlist_head *h_list;
 109         struct hlist_node *list, *parent;
 110         unsigned int hashed_key;
 111         unsigned long key = item->key;
 112
 113         hashed_key = hash_long(key, ht->order);
 114         h_list = &ht->table[hashed_key];
 115         parent = NULL;
 116         hlist_for_each(list, h_list) {
 117                 entry = hlist_entry(list, struct drm_hash_item, head);
 118                 if (entry->key == key)
 119                         return -EINVAL;
 120                 if (entry->key > key)
 121                         break;
 122                 parent = list;
 123         }
 124         if (parent) {
 125                 hlist_add_after(parent, &item->head);
 126         } else {
 127                 hlist_add_head(&item->head, h_list);
 128         }
 129         return 0;
 130 }
 131 EXPORT_SYMBOL(drm_ht_insert_item);
 132
 133 /*
 134  * Just insert an item and return any "bits" bit key that hasn't been
 135  * used before.
 136  */
 137 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
 138                               unsigned long seed, int bits, int shift,
 139                               unsigned long add)
 140 {
 141         int ret;
 142         unsigned long mask = (1 << bits) - 1;
 143         unsigned long first, unshifted_key;
 144
 145         unshifted_key = hash_long(seed, bits);
 146         first = unshifted_key;
 147         do {
 148                 item->key = (unshifted_key << shift) + add;
 149                 ret = drm_ht_insert_item(ht, item);
 150                 if (ret)
 151                         unshifted_key = (unshifted_key + 1) & mask;
 152         } while(ret && (unshifted_key != first));
 153
 154         if (ret) {
 155                 DRM_ERROR("Available key bit space exhausted\n");
 156                 return -EINVAL;
 157         }
 158         return 0;
 159 }
 160 EXPORT_SYMBOL(drm_ht_just_insert_please);
 161
 162 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 163                      struct drm_hash_item **item)
 164 {
 165         struct hlist_node *list;
 166
 167         list = drm_ht_find_key(ht, key);
 168         if (!list)
 169                 return -EINVAL;
 170
 171         *item = hlist_entry(list, struct drm_hash_item, head);
 172         return 0;
 173 }
 174 EXPORT_SYMBOL(drm_ht_find_item);
 175
 176 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
 177 {
 178         struct hlist_node *list;
 179
 180         list = drm_ht_find_key(ht, key);
 181         if (list) {
 182                 hlist_del_init(list);
 183                 ht->fill--;
 184                 return 0;
 185         }
 186         return -EINVAL;
 187 }
 188
 189 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 190 {
 191         hlist_del_init(&item->head);
 192         ht->fill--;
 193         return 0;
 194 }
 195 EXPORT_SYMBOL(drm_ht_remove_item);
 196
 197 void drm_ht_remove(struct drm_open_hash *ht)
 198 {
 199         if (ht->table) {
 200                 if (ht->use_vmalloc)
 201                         vfree(ht->table);
 202                 else
 203                         kfree(ht->table);
 204                 ht->table = NULL;
 205         }
 206 }
 207 EXPORT_SYMBOL(drm_ht_remove);