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 <linux/export.h> 36 #include <linux/hash.h> 37 #include <linux/mm.h> 38 #include <linux/rculist.h> 39 #include <linux/slab.h> 40 #include <linux/vmalloc.h> 41 42 #include <drm/drm_hashtab.h> 43 #include <drm/drm_print.h> 44 45 int drm_ht_create(struct drm_open_hash *ht, unsigned int order) 46 { 47 unsigned int size = 1 << order; 48 49 ht->order = order; 50 ht->table = NULL; 51 if (size <= PAGE_SIZE / sizeof(*ht->table)) 52 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL); 53 else 54 ht->table = vzalloc(array_size(size, sizeof(*ht->table))); 55 if (!ht->table) { 56 DRM_ERROR("Out of memory for hash table\n"); 57 return -ENOMEM; 58 } 59 return 0; 60 } 61 EXPORT_SYMBOL(drm_ht_create); 62 63 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 64 { 65 struct drm_hash_item *entry; 66 struct hlist_head *h_list; 67 unsigned int hashed_key; 68 int count = 0; 69 70 hashed_key = hash_long(key, ht->order); 71 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 72 h_list = &ht->table[hashed_key]; 73 hlist_for_each_entry(entry, h_list, head) 74 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 75 } 76 77 #ifdef notyet 78 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 79 unsigned long key) 80 { 81 struct drm_hash_item *entry; 82 struct hlist_head *h_list; 83 unsigned int hashed_key; 84 85 hashed_key = hash_long(key, ht->order); 86 h_list = &ht->table[hashed_key]; 87 hlist_for_each_entry(entry, h_list, head) { 88 if (entry->key == key) 89 return &entry->head; 90 if (entry->key > key) 91 break; 92 } 93 return NULL; 94 } 95 #endif 96 97 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 98 unsigned long key) 99 { 100 STUB(); 101 return NULL; 102 #ifdef notyet 103 struct drm_hash_item *entry; 104 struct hlist_head *h_list; 105 unsigned int hashed_key; 106 107 hashed_key = hash_long(key, ht->order); 108 h_list = &ht->table[hashed_key]; 109 hlist_for_each_entry_rcu(entry, h_list, head) { 110 if (entry->key == key) 111 return &entry->head; 112 if (entry->key > key) 113 break; 114 } 115 return NULL; 116 #endif 117 } 118 119 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 120 { 121 STUB(); 122 return -ENOSYS; 123 #ifdef notyet 124 struct drm_hash_item *entry; 125 struct hlist_head *h_list; 126 struct hlist_node *parent; 127 unsigned int hashed_key; 128 unsigned long key = item->key; 129 130 hashed_key = hash_long(key, ht->order); 131 h_list = &ht->table[hashed_key]; 132 parent = NULL; 133 hlist_for_each_entry(entry, h_list, head) { 134 if (entry->key == key) 135 return -EINVAL; 136 if (entry->key > key) 137 break; 138 parent = &entry->head; 139 } 140 if (parent) { 141 hlist_add_behind_rcu(&item->head, parent); 142 } else { 143 hlist_add_head_rcu(&item->head, h_list); 144 } 145 return 0; 146 #endif 147 } 148 EXPORT_SYMBOL(drm_ht_insert_item); 149 150 /* 151 * Just insert an item and return any "bits" bit key that hasn't been 152 * used before. 153 */ 154 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 155 unsigned long seed, int bits, int shift, 156 unsigned long add) 157 { 158 int ret; 159 unsigned long mask = (1UL << bits) - 1; 160 unsigned long first, unshifted_key; 161 162 unshifted_key = hash_long(seed, bits); 163 first = unshifted_key; 164 do { 165 item->key = (unshifted_key << shift) + add; 166 ret = drm_ht_insert_item(ht, item); 167 if (ret) 168 unshifted_key = (unshifted_key + 1) & mask; 169 } while(ret && (unshifted_key != first)); 170 171 if (ret) { 172 DRM_ERROR("Available key bit space exhausted\n"); 173 return -EINVAL; 174 } 175 return 0; 176 } 177 EXPORT_SYMBOL(drm_ht_just_insert_please); 178 179 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 180 struct drm_hash_item **item) 181 { 182 struct hlist_node *list; 183 184 list = drm_ht_find_key_rcu(ht, key); 185 if (!list) 186 return -EINVAL; 187 188 *item = hlist_entry(list, struct drm_hash_item, head); 189 return 0; 190 } 191 EXPORT_SYMBOL(drm_ht_find_item); 192 193 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 194 { 195 STUB(); 196 return -ENOSYS; 197 #ifdef notyet 198 struct hlist_node *list; 199 200 list = drm_ht_find_key(ht, key); 201 if (list) { 202 hlist_del_init_rcu(list); 203 return 0; 204 } 205 return -EINVAL; 206 #endif 207 } 208 209 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 210 { 211 STUB(); 212 return -ENOSYS; 213 #ifdef notyet 214 hlist_del_init_rcu(&item->head); 215 return 0; 216 #endif 217 } 218 EXPORT_SYMBOL(drm_ht_remove_item); 219 220 void drm_ht_remove(struct drm_open_hash *ht) 221 { 222 if (ht->table) { 223 kvfree(ht->table); 224 ht->table = NULL; 225 } 226 } 227 EXPORT_SYMBOL(drm_ht_remove); 228