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