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 39 int drm_ht_create(struct drm_open_hash *ht, unsigned int order) 40 { 41 unsigned int i; 42 43 ht->size = 1 << order; 44 ht->order = order; 45 ht->fill = 0; 46 ht->table = NULL; 47 ht->use_vmalloc = ((ht->size * sizeof(*ht->table)) > PAGE_SIZE); 48 if (!ht->use_vmalloc) { 49 ht->table = kcalloc(ht->size, sizeof(*ht->table), GFP_KERNEL); 50 } 51 if (!ht->table) { 52 ht->use_vmalloc = 1; 53 ht->table = vmalloc(ht->size*sizeof(*ht->table)); 54 } 55 if (!ht->table) { 56 DRM_ERROR("Out of memory for hash table\n"); 57 return -ENOMEM; 58 } 59 for (i=0; i< ht->size; ++i) { 60 INIT_HLIST_HEAD(&ht->table[i]); 61 } 62 return 0; 63 } 64 EXPORT_SYMBOL(drm_ht_create); 65 66 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 67 { 68 struct drm_hash_item *entry; 69 struct hlist_head *h_list; 70 struct hlist_node *list; 71 unsigned int hashed_key; 72 int count = 0; 73 74 hashed_key = hash_long(key, ht->order); 75 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 76 h_list = &ht->table[hashed_key]; 77 hlist_for_each(list, h_list) { 78 entry = hlist_entry(list, struct drm_hash_item, head); 79 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 80 } 81 } 82 83 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 84 unsigned long key) 85 { 86 struct drm_hash_item *entry; 87 struct hlist_head *h_list; 88 struct hlist_node *list; 89 unsigned int hashed_key; 90 91 hashed_key = hash_long(key, ht->order); 92 h_list = &ht->table[hashed_key]; 93 hlist_for_each(list, h_list) { 94 entry = hlist_entry(list, struct drm_hash_item, head); 95 if (entry->key == key) 96 return list; 97 if (entry->key > key) 98 break; 99 } 100 return NULL; 101 } 102 103 104 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 105 { 106 struct drm_hash_item *entry; 107 struct hlist_head *h_list; 108 struct hlist_node *list, *parent; 109 unsigned int hashed_key; 110 unsigned long key = item->key; 111 112 hashed_key = hash_long(key, ht->order); 113 h_list = &ht->table[hashed_key]; 114 parent = NULL; 115 hlist_for_each(list, h_list) { 116 entry = hlist_entry(list, struct drm_hash_item, head); 117 if (entry->key == key) 118 return -EINVAL; 119 if (entry->key > key) 120 break; 121 parent = list; 122 } 123 if (parent) { 124 hlist_add_after(parent, &item->head); 125 } else { 126 hlist_add_head(&item->head, h_list); 127 } 128 return 0; 129 } 130 EXPORT_SYMBOL(drm_ht_insert_item); 131 132 /* 133 * Just insert an item and return any "bits" bit key that hasn't been 134 * used before. 135 */ 136 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 137 unsigned long seed, int bits, int shift, 138 unsigned long add) 139 { 140 int ret; 141 unsigned long mask = (1 << bits) - 1; 142 unsigned long first, unshifted_key; 143 144 unshifted_key = hash_long(seed, bits); 145 first = unshifted_key; 146 do { 147 item->key = (unshifted_key << shift) + add; 148 ret = drm_ht_insert_item(ht, item); 149 if (ret) 150 unshifted_key = (unshifted_key + 1) & mask; 151 } while(ret && (unshifted_key != first)); 152 153 if (ret) { 154 DRM_ERROR("Available key bit space exhausted\n"); 155 return -EINVAL; 156 } 157 return 0; 158 } 159 EXPORT_SYMBOL(drm_ht_just_insert_please); 160 161 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 162 struct drm_hash_item **item) 163 { 164 struct hlist_node *list; 165 166 list = drm_ht_find_key(ht, key); 167 if (!list) 168 return -EINVAL; 169 170 *item = hlist_entry(list, struct drm_hash_item, head); 171 return 0; 172 } 173 EXPORT_SYMBOL(drm_ht_find_item); 174 175 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 176 { 177 struct hlist_node *list; 178 179 list = drm_ht_find_key(ht, key); 180 if (list) { 181 hlist_del_init(list); 182 ht->fill--; 183 return 0; 184 } 185 return -EINVAL; 186 } 187 188 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 189 { 190 hlist_del_init(&item->head); 191 ht->fill--; 192 return 0; 193 } 194 EXPORT_SYMBOL(drm_ht_remove_item); 195 196 void drm_ht_remove(struct drm_open_hash *ht) 197 { 198 if (ht->table) { 199 if (ht->use_vmalloc) 200 vfree(ht->table); 201 else 202 kfree(ht->table); 203 ht->table = NULL; 204 } 205 } 206 EXPORT_SYMBOL(drm_ht_remove); 207