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 40 int drm_ht_create(struct drm_open_hash *ht, unsigned int order) 41 { 42 unsigned int i; 43 44 ht->size = 1 << order; 45 ht->order = order; 46 ht->fill = 0; 47 ht->table = NULL; 48 ht->use_vmalloc = ((ht->size * sizeof(*ht->table)) > PAGE_SIZE); 49 if (!ht->use_vmalloc) { 50 ht->table = kcalloc(ht->size, sizeof(*ht->table), GFP_KERNEL); 51 } 52 if (!ht->table) { 53 ht->use_vmalloc = 1; 54 ht->table = vmalloc(ht->size*sizeof(*ht->table)); 55 } 56 if (!ht->table) { 57 DRM_ERROR("Out of memory for hash table\n"); 58 return -ENOMEM; 59 } 60 for (i=0; i< ht->size; ++i) { 61 INIT_HLIST_HEAD(&ht->table[i]); 62 } 63 return 0; 64 } 65 EXPORT_SYMBOL(drm_ht_create); 66 67 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 68 { 69 struct drm_hash_item *entry; 70 struct hlist_head *h_list; 71 struct hlist_node *list; 72 unsigned int hashed_key; 73 int count = 0; 74 75 hashed_key = hash_long(key, ht->order); 76 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 77 h_list = &ht->table[hashed_key]; 78 hlist_for_each(list, h_list) { 79 entry = hlist_entry(list, struct drm_hash_item, head); 80 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 81 } 82 } 83 84 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 85 unsigned long key) 86 { 87 struct drm_hash_item *entry; 88 struct hlist_head *h_list; 89 struct hlist_node *list; 90 unsigned int hashed_key; 91 92 hashed_key = hash_long(key, ht->order); 93 h_list = &ht->table[hashed_key]; 94 hlist_for_each(list, h_list) { 95 entry = hlist_entry(list, struct drm_hash_item, head); 96 if (entry->key == key) 97 return list; 98 if (entry->key > key) 99 break; 100 } 101 return NULL; 102 } 103 104 105 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 106 { 107 struct drm_hash_item *entry; 108 struct hlist_head *h_list; 109 struct hlist_node *list, *parent; 110 unsigned int hashed_key; 111 unsigned long key = item->key; 112 113 hashed_key = hash_long(key, ht->order); 114 h_list = &ht->table[hashed_key]; 115 parent = NULL; 116 hlist_for_each(list, h_list) { 117 entry = hlist_entry(list, struct drm_hash_item, head); 118 if (entry->key == key) 119 return -EINVAL; 120 if (entry->key > key) 121 break; 122 parent = list; 123 } 124 if (parent) { 125 hlist_add_after(parent, &item->head); 126 } else { 127 hlist_add_head(&item->head, h_list); 128 } 129 return 0; 130 } 131 EXPORT_SYMBOL(drm_ht_insert_item); 132 133 /* 134 * Just insert an item and return any "bits" bit key that hasn't been 135 * used before. 136 */ 137 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 138 unsigned long seed, int bits, int shift, 139 unsigned long add) 140 { 141 int ret; 142 unsigned long mask = (1 << bits) - 1; 143 unsigned long first, unshifted_key; 144 145 unshifted_key = hash_long(seed, bits); 146 first = unshifted_key; 147 do { 148 item->key = (unshifted_key << shift) + add; 149 ret = drm_ht_insert_item(ht, item); 150 if (ret) 151 unshifted_key = (unshifted_key + 1) & mask; 152 } while(ret && (unshifted_key != first)); 153 154 if (ret) { 155 DRM_ERROR("Available key bit space exhausted\n"); 156 return -EINVAL; 157 } 158 return 0; 159 } 160 EXPORT_SYMBOL(drm_ht_just_insert_please); 161 162 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 163 struct drm_hash_item **item) 164 { 165 struct hlist_node *list; 166 167 list = drm_ht_find_key(ht, key); 168 if (!list) 169 return -EINVAL; 170 171 *item = hlist_entry(list, struct drm_hash_item, head); 172 return 0; 173 } 174 EXPORT_SYMBOL(drm_ht_find_item); 175 176 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 177 { 178 struct hlist_node *list; 179 180 list = drm_ht_find_key(ht, key); 181 if (list) { 182 hlist_del_init(list); 183 ht->fill--; 184 return 0; 185 } 186 return -EINVAL; 187 } 188 189 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 190 { 191 hlist_del_init(&item->head); 192 ht->fill--; 193 return 0; 194 } 195 EXPORT_SYMBOL(drm_ht_remove_item); 196 197 void drm_ht_remove(struct drm_open_hash *ht) 198 { 199 if (ht->table) { 200 if (ht->use_vmalloc) 201 vfree(ht->table); 202 else 203 kfree(ht->table); 204 ht->table = NULL; 205 } 206 } 207 EXPORT_SYMBOL(drm_ht_remove); 208