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 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 78 unsigned long key) 79 { 80 struct drm_hash_item *entry; 81 struct hlist_head *h_list; 82 unsigned int hashed_key; 83 84 hashed_key = hash_long(key, ht->order); 85 h_list = &ht->table[hashed_key]; 86 hlist_for_each_entry(entry, h_list, head) { 87 if (entry->key == key) 88 return &entry->head; 89 if (entry->key > key) 90 break; 91 } 92 return NULL; 93 } 94 95 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 96 unsigned long key) 97 { 98 struct drm_hash_item *entry; 99 struct hlist_head *h_list; 100 unsigned int hashed_key; 101 102 hashed_key = hash_long(key, ht->order); 103 h_list = &ht->table[hashed_key]; 104 hlist_for_each_entry_rcu(entry, h_list, head) { 105 if (entry->key == key) 106 return &entry->head; 107 if (entry->key > key) 108 break; 109 } 110 return NULL; 111 } 112 113 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 114 { 115 struct drm_hash_item *entry; 116 struct hlist_head *h_list; 117 struct hlist_node *parent; 118 unsigned int hashed_key; 119 unsigned long key = item->key; 120 121 hashed_key = hash_long(key, ht->order); 122 h_list = &ht->table[hashed_key]; 123 parent = NULL; 124 hlist_for_each_entry(entry, h_list, head) { 125 if (entry->key == key) 126 return -EINVAL; 127 if (entry->key > key) 128 break; 129 parent = &entry->head; 130 } 131 if (parent) { 132 hlist_add_behind_rcu(&item->head, parent); 133 } else { 134 hlist_add_head_rcu(&item->head, h_list); 135 } 136 return 0; 137 } 138 EXPORT_SYMBOL(drm_ht_insert_item); 139 140 /* 141 * Just insert an item and return any "bits" bit key that hasn't been 142 * used before. 143 */ 144 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 145 unsigned long seed, int bits, int shift, 146 unsigned long add) 147 { 148 int ret; 149 unsigned long mask = (1UL << bits) - 1; 150 unsigned long first, unshifted_key; 151 152 unshifted_key = hash_long(seed, bits); 153 first = unshifted_key; 154 do { 155 item->key = (unshifted_key << shift) + add; 156 ret = drm_ht_insert_item(ht, item); 157 if (ret) 158 unshifted_key = (unshifted_key + 1) & mask; 159 } while(ret && (unshifted_key != first)); 160 161 if (ret) { 162 DRM_ERROR("Available key bit space exhausted\n"); 163 return -EINVAL; 164 } 165 return 0; 166 } 167 EXPORT_SYMBOL(drm_ht_just_insert_please); 168 169 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 170 struct drm_hash_item **item) 171 { 172 struct hlist_node *list; 173 174 list = drm_ht_find_key_rcu(ht, key); 175 if (!list) 176 return -EINVAL; 177 178 *item = hlist_entry(list, struct drm_hash_item, head); 179 return 0; 180 } 181 EXPORT_SYMBOL(drm_ht_find_item); 182 183 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 184 { 185 struct hlist_node *list; 186 187 list = drm_ht_find_key(ht, key); 188 if (list) { 189 hlist_del_init_rcu(list); 190 return 0; 191 } 192 return -EINVAL; 193 } 194 195 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 196 { 197 hlist_del_init_rcu(&item->head); 198 return 0; 199 } 200 EXPORT_SYMBOL(drm_ht_remove_item); 201 202 void drm_ht_remove(struct drm_open_hash *ht) 203 { 204 if (ht->table) { 205 kvfree(ht->table); 206 ht->table = NULL; 207 } 208 } 209 EXPORT_SYMBOL(drm_ht_remove); 210