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 <drm/drmP.h>
  36 #include <drm/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_entry(entry, list, h_list, head)
  71                 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
  72 }
  73
  74 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht,
  75                                           unsigned long key)
  76 {
  77         struct drm_hash_item *entry;
  78         struct hlist_head *h_list;
  79         struct hlist_node *list;
  80         unsigned int hashed_key;
  81
  82         hashed_key = hash_long(key, ht->order);
  83         h_list = &ht->table[hashed_key];
  84         hlist_for_each_entry(entry, list, h_list, head) {
  85                 if (entry->key == key)
  86                         return list;
  87                 if (entry->key > key)
  88                         break;
  89         }
  90         return NULL;
  91 }
  92
  93 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht,
  94                                               unsigned long key)
  95 {
  96         struct drm_hash_item *entry;
  97         struct hlist_head *h_list;
  98         struct hlist_node *list;
  99         unsigned int hashed_key;
 100
 101         hashed_key = hash_long(key, ht->order);
 102         h_list = &ht->table[hashed_key];
 103         hlist_for_each_entry_rcu(entry, list, h_list, head) {
 104                 if (entry->key == key)
 105                         return list;
 106                 if (entry->key > key)
 107                         break;
 108         }
 109         return NULL;
 110 }
 111
 112 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 113 {
 114         struct drm_hash_item *entry;
 115         struct hlist_head *h_list;
 116         struct hlist_node *list, *parent;
 117         unsigned int hashed_key;
 118         unsigned long key = item->key;
 119
 120         hashed_key = hash_long(key, ht->order);
 121         h_list = &ht->table[hashed_key];
 122         parent = NULL;
 123         hlist_for_each_entry(entry, list, h_list, head) {
 124                 if (entry->key == key)
 125                         return -EINVAL;
 126                 if (entry->key > key)
 127                         break;
 128                 parent = list;
 129         }
 130         if (parent) {
 131                 hlist_add_after_rcu(parent, &item->head);
 132         } else {
 133                 hlist_add_head_rcu(&item->head, h_list);
 134         }
 135         return 0;
 136 }
 137 EXPORT_SYMBOL(drm_ht_insert_item);
 138
 139 /*
 140  * Just insert an item and return any "bits" bit key that hasn't been
 141  * used before.
 142  */
 143 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
 144                               unsigned long seed, int bits, int shift,
 145                               unsigned long add)
 146 {
 147         int ret;
 148         unsigned long mask = (1 << bits) - 1;
 149         unsigned long first, unshifted_key;
 150
 151         unshifted_key = hash_long(seed, bits);
 152         first = unshifted_key;
 153         do {
 154                 item->key = (unshifted_key << shift) + add;
 155                 ret = drm_ht_insert_item(ht, item);
 156                 if (ret)
 157                         unshifted_key = (unshifted_key + 1) & mask;
 158         } while(ret && (unshifted_key != first));
 159
 160         if (ret) {
 161                 DRM_ERROR("Available key bit space exhausted\n");
 162                 return -EINVAL;
 163         }
 164         return 0;
 165 }
 166 EXPORT_SYMBOL(drm_ht_just_insert_please);
 167
 168 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 169                      struct drm_hash_item **item)
 170 {
 171         struct hlist_node *list;
 172
 173         list = drm_ht_find_key_rcu(ht, key);
 174         if (!list)
 175                 return -EINVAL;
 176
 177         *item = hlist_entry(list, struct drm_hash_item, head);
 178         return 0;
 179 }
 180 EXPORT_SYMBOL(drm_ht_find_item);
 181
 182 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
 183 {
 184         struct hlist_node *list;
 185
 186         list = drm_ht_find_key(ht, key);
 187         if (list) {
 188                 hlist_del_init_rcu(list);
 189                 return 0;
 190         }
 191         return -EINVAL;
 192 }
 193
 194 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 195 {
 196         hlist_del_init_rcu(&item->head);
 197         return 0;
 198 }
 199 EXPORT_SYMBOL(drm_ht_remove_item);
 200
 201 void drm_ht_remove(struct drm_open_hash *ht)
 202 {
 203         if (ht->table) {
 204                 if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order)
 205                         kfree(ht->table);
 206                 else
 207                         vfree(ht->table);
 208                 ht->table = NULL;
 209         }
 210 }
 211 EXPORT_SYMBOL(drm_ht_remove);