sys/dev/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  * __FBSDID("$FreeBSD: src/sys/dev/drm/drm_hashtab.c,v 1.1 2010/01/31 14:25:29 rnoland Exp $");
  28  **************************************************************************/
  29
  30 /*
  31  * Simple open hash tab implementation.
  32  *
  33  * Authors:
  34  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  35  */
  36
  37 #include "dev/drm/drmP.h"
  38 #include "dev/drm/drm_hashtab.h"
  39
  40 #if defined(__DragonFly__)
  41 #include "dev/drm/drm_priv_hash.h"
  42 #else
  43 #include <sys/hash.h>
  44 #endif
  45
  46 int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
  47 {
  48         ht->size = 1 << order;
  49         ht->order = order;
  50         ht->table = NULL;
  51         ht->table = drm_hashinit(ht->size, DRM_MEM_HASHTAB, &ht->mask);
  52         if (!ht->table) {
  53                 DRM_ERROR("Out of memory for hash table\n");
  54                 return -ENOMEM;
  55         }
  56         return 0;
  57 }
  58
  59 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
  60 {
  61         struct drm_hash_item *entry;
  62         struct drm_hash_item_list *h_list;
  63         unsigned int hashed_key;
  64         int count = 0;
  65
  66         hashed_key = hash32_buf(&key, sizeof(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 & ht->mask];
  69         LIST_FOREACH(entry, h_list, head)
  70                 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
  71 }
  72
  73 static struct drm_hash_item *
  74 drm_ht_find_key(struct drm_open_hash *ht, unsigned long key)
  75 {
  76         struct drm_hash_item *entry;
  77         struct drm_hash_item_list *h_list;
  78         unsigned int hashed_key;
  79
  80         hashed_key = hash32_buf(&key, sizeof(key), ht->order);
  81         h_list = &ht->table[hashed_key & ht->mask];
  82         LIST_FOREACH(entry, h_list, head) {
  83                 if (entry->key == key)
  84                         return entry;
  85                 if (entry->key > key)
  86                         break;
  87         }
  88         return NULL;
  89 }
  90
  91
  92 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
  93 {
  94         struct drm_hash_item *entry, *parent;
  95         struct drm_hash_item_list *h_list;
  96         unsigned int hashed_key;
  97         unsigned long key = item->key;
  98
  99         hashed_key = hash32_buf(&key, sizeof(key), ht->order);
 100         h_list = &ht->table[hashed_key & ht->mask];
 101         parent = NULL;
 102         LIST_FOREACH(entry, h_list, head) {
 103                 if (entry->key == key)
 104                         return -EINVAL;
 105                 if (entry->key > key)
 106                         break;
 107                 parent = entry;
 108         }
 109         if (parent) {
 110                 LIST_INSERT_AFTER(parent, item, head);
 111         } else {
 112                 LIST_INSERT_HEAD(h_list, item, head);
 113         }
 114         return 0;
 115 }
 116
 117 /*
 118  * Just insert an item and return any "bits" bit key that hasn't been
 119  * used before.
 120  */
 121 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
 122                               unsigned long seed, int bits, int shift,
 123                               unsigned long add)
 124 {
 125         int ret;
 126         unsigned long mask = (1 << bits) - 1;
 127         unsigned long first, unshifted_key = 0;
 128
 129         unshifted_key = hash32_buf(&seed, sizeof(seed), unshifted_key);
 130         first = unshifted_key;
 131         do {
 132                 item->key = (unshifted_key << shift) + add;
 133                 ret = drm_ht_insert_item(ht, item);
 134                 if (ret)
 135                         unshifted_key = (unshifted_key + 1) & mask;
 136         } while(ret && (unshifted_key != first));
 137
 138         if (ret) {
 139                 DRM_ERROR("Available key bit space exhausted\n");
 140                 return -EINVAL;
 141         }
 142         return 0;
 143 }
 144
 145 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
 146                      struct drm_hash_item **item)
 147 {
 148         struct drm_hash_item *entry;
 149
 150         entry = drm_ht_find_key(ht, key);
 151         if (!entry)
 152                 return -EINVAL;
 153
 154         *item = entry;
 155         return 0;
 156 }
 157
 158 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
 159 {
 160         struct drm_hash_item *entry;
 161
 162         entry = drm_ht_find_key(ht, key);
 163         if (entry) {
 164                 LIST_REMOVE(entry, head);
 165                 return 0;
 166         }
 167         return -EINVAL;
 168 }
 169
 170 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
 171 {
 172         LIST_REMOVE(item, head);
 173         return 0;
 174 }
 175
 176 void drm_ht_remove(struct drm_open_hash *ht)
 177 {
 178         if (ht->table) {
 179                 drm_hashdestroy(ht->table, DRM_MEM_HASHTAB, ht->mask);
 180                 ht->table = NULL;
 181         }
 182 }