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