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 = vzalloc(size*sizeof(*ht->table)); 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 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_entry(entry, h_list, head) 70 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 71 } 72 73 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 74 unsigned long key) 75 { 76 struct drm_hash_item *entry; 77 struct hlist_head *h_list; 78 unsigned int hashed_key; 79 80 hashed_key = hash_long(key, ht->order); 81 h_list = &ht->table[hashed_key]; 82 hlist_for_each_entry(entry, h_list, head) { 83 if (entry->key == key) 84 return &entry->head; 85 if (entry->key > key) 86 break; 87 } 88 return NULL; 89 } 90 91 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 92 unsigned long key) 93 { 94 struct drm_hash_item *entry; 95 struct hlist_head *h_list; 96 unsigned int hashed_key; 97 98 hashed_key = hash_long(key, ht->order); 99 h_list = &ht->table[hashed_key]; 100 hlist_for_each_entry_rcu(entry, h_list, head) { 101 if (entry->key == key) 102 return &entry->head; 103 if (entry->key > key) 104 break; 105 } 106 return NULL; 107 } 108 109 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 110 { 111 struct drm_hash_item *entry; 112 struct hlist_head *h_list; 113 struct hlist_node *parent; 114 unsigned int hashed_key; 115 unsigned long key = item->key; 116 117 hashed_key = hash_long(key, ht->order); 118 h_list = &ht->table[hashed_key]; 119 parent = NULL; 120 hlist_for_each_entry(entry, h_list, head) { 121 if (entry->key == key) 122 return -EINVAL; 123 if (entry->key > key) 124 break; 125 parent = &entry->head; 126 } 127 if (parent) { 128 hlist_add_behind_rcu(&item->head, parent); 129 } else { 130 hlist_add_head_rcu(&item->head, h_list); 131 } 132 return 0; 133 } 134 EXPORT_SYMBOL(drm_ht_insert_item); 135 136 /* 137 * Just insert an item and return any "bits" bit key that hasn't been 138 * used before. 139 */ 140 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 141 unsigned long seed, int bits, int shift, 142 unsigned long add) 143 { 144 int ret; 145 unsigned long mask = (1 << bits) - 1; 146 unsigned long first, unshifted_key; 147 148 unshifted_key = hash_long(seed, bits); 149 first = unshifted_key; 150 do { 151 item->key = (unshifted_key << shift) + add; 152 ret = drm_ht_insert_item(ht, item); 153 if (ret) 154 unshifted_key = (unshifted_key + 1) & mask; 155 } while(ret && (unshifted_key != first)); 156 157 if (ret) { 158 DRM_ERROR("Available key bit space exhausted\n"); 159 return -EINVAL; 160 } 161 return 0; 162 } 163 EXPORT_SYMBOL(drm_ht_just_insert_please); 164 165 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 166 struct drm_hash_item **item) 167 { 168 struct hlist_node *list; 169 170 list = drm_ht_find_key_rcu(ht, key); 171 if (!list) 172 return -EINVAL; 173 174 *item = hlist_entry(list, struct drm_hash_item, head); 175 return 0; 176 } 177 EXPORT_SYMBOL(drm_ht_find_item); 178 179 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 180 { 181 struct hlist_node *list; 182 183 list = drm_ht_find_key(ht, key); 184 if (list) { 185 hlist_del_init_rcu(list); 186 return 0; 187 } 188 return -EINVAL; 189 } 190 191 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 192 { 193 hlist_del_init_rcu(&item->head); 194 return 0; 195 } 196 EXPORT_SYMBOL(drm_ht_remove_item); 197 198 void drm_ht_remove(struct drm_open_hash *ht) 199 { 200 if (ht->table) { 201 if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order) 202 kfree(ht->table); 203 else 204 vfree(ht->table); 205 ht->table = NULL; 206 } 207 } 208 EXPORT_SYMBOL(drm_ht_remove); 209