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
  41 int 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 }
  57 EXPORT_SYMBOL(drm_ht_create);
  58
  59 void 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
  76 static 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
  97 int 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 }
 123 EXPORT_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  */
 129 int 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 }
 152 EXPORT_SYMBOL(drm_ht_just_insert_please);
 153
 154 int 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 }
 166 EXPORT_SYMBOL(drm_ht_find_item);
 167
 168 int 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
 180 int 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 }
 185 EXPORT_SYMBOL(drm_ht_remove_item);
 186
 187 void 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 }
 197 EXPORT_SYMBOL(drm_ht_remove);