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 <linux/export.h>
  36 #include <linux/hash.h>
  37 #include <linux/mm.h>
  38 #include <linux/rculist.h>
  39 #include <linux/slab.h>
  40 #include <linux/vmalloc.h>
  41
  42 #include <drm/drm_hashtab.h>
  43 #include <drm/drm_print.h>
  44
  45 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
  46 {
  47         unsigned int size = 1 << order;
  48
  49         ht->order = order;
  50         ht->table = NULL;
  51         if (size <= PAGE_SIZE / sizeof(*ht->table))
  52                 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL);
  53         else
  54                 ht->table = vzalloc(array_size(size, sizeof(*ht->table)));
  55         if (!ht->table) {
  56                 DRM_ERROR("Out of memory for hash table\n");
  57                 return -ENOMEM;
  58         }
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(drm_ht_create);
  62
  63 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
  64 {
  65         struct drm_hash_item *entry;
  66         struct hlist_head *h_list;
  67         unsigned int hashed_key;
  68         int count = 0;
  69
  70         hashed_key = hash_long(key, ht->order);
  71         DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
  72         h_list = &ht->table[hashed_key];
  73         hlist_for_each_entry(entry, h_list, head)
  74                 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
  75 }
  76
  77 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
  78                                           unsigned long key)
  79 {
  80         struct drm_hash_item *entry;
  81         struct hlist_head *h_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_entry(entry, h_list, head) {
  87                 if (entry->key == key)
  88                         return &entry->head;
  89                 if (entry->key > key)
  90                         break;
  91         }
  92         return NULL;
  93 }
  94
  95 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
  96                                               unsigned long key)
  97 {
  98         struct drm_hash_item *entry;
  99         struct hlist_head *h_list;
 100         unsigned int hashed_key;
 101
 102         hashed_key = hash_long(key, ht->order);
 103         h_list = &ht->table[hashed_key];
 104         hlist_for_each_entry_rcu(entry, h_list, head) {
 105                 if (entry->key == key)
 106                         return &entry->head;
 107                 if (entry->key > key)
 108                         break;
 109         }
 110         return NULL;
 111 }
 112
 113 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 114 {
 115         struct drm_hash_item *entry;
 116         struct hlist_head *h_list;
 117         struct hlist_node *parent;
 118         unsigned int hashed_key;
 119         unsigned long key = item->key;
 120
 121         hashed_key = hash_long(key, ht->order);
 122         h_list = &ht->table[hashed_key];
 123         parent = NULL;
 124         hlist_for_each_entry(entry, h_list, head) {
 125                 if (entry->key == key)
 126                         return -EINVAL;
 127                 if (entry->key > key)
 128                         break;
 129                 parent = &entry->head;
 130         }
 131         if (parent) {
 132                 hlist_add_behind_rcu(&item->head, parent);
 133         } else {
 134                 hlist_add_head_rcu(&item->head, h_list);
 135         }
 136         return 0;
 137 }
 138 EXPORT_SYMBOL(drm_ht_insert_item);
 139
 140 /*
 141  * Just insert an item and return any "bits" bit key that hasn't been
 142  * used before.
 143  */
 144 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
 145                               unsigned long seed, int bits, int shift,
 146                               unsigned long add)
 147 {
 148         int ret;
 149         unsigned long mask = (1UL << bits) - 1;
 150         unsigned long first, unshifted_key;
 151
 152         unshifted_key = hash_long(seed, bits);
 153         first = unshifted_key;
 154         do {
 155                 item->key = (unshifted_key << shift) + add;
 156                 ret = drm_ht_insert_item(ht, item);
 157                 if (ret)
 158                         unshifted_key = (unshifted_key + 1) & mask;
 159         } while(ret && (unshifted_key != first));
 160
 161         if (ret) {
 162                 DRM_ERROR("Available key bit space exhausted\n");
 163                 return -EINVAL;
 164         }
 165         return 0;
 166 }
 167 EXPORT_SYMBOL(drm_ht_just_insert_please);
 168
 169 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 170                      struct drm_hash_item **item)
 171 {
 172         struct hlist_node *list;
 173
 174         list = drm_ht_find_key_rcu(ht, key);
 175         if (!list)
 176                 return -EINVAL;
 177
 178         *item = hlist_entry(list, struct drm_hash_item, head);
 179         return 0;
 180 }
 181 EXPORT_SYMBOL(drm_ht_find_item);
 182
 183 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
 184 {
 185         struct hlist_node *list;
 186
 187         list = drm_ht_find_key(ht, key);
 188         if (list) {
 189                 hlist_del_init_rcu(list);
 190                 return 0;
 191         }
 192         return -EINVAL;
 193 }
 194
 195 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 196 {
 197         hlist_del_init_rcu(&item->head);
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(drm_ht_remove_item);
 201
 202 void drm_ht_remove(struct drm_open_hash *ht)
 203 {
 204         if (ht->table) {
 205                 kvfree(ht->table);
 206                 ht->table = NULL;
 207         }
 208 }
 209 EXPORT_SYMBOL(drm_ht_remove);