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