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/hash.h> 36 #include <linux/mm.h> 37 #include <linux/rculist.h> 38 #include <linux/slab.h> 39 #include <linux/vmalloc.h> 40 41 #include <drm/drm_print.h> 42 43 #include "drm_legacy.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 62 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 63 { 64 struct drm_hash_item *entry; 65 struct hlist_head *h_list; 66 unsigned int hashed_key; 67 int count = 0; 68 69 hashed_key = hash_long(key, ht->order); 70 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 71 h_list = &ht->table[hashed_key]; 72 hlist_for_each_entry(entry, h_list, head) 73 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 74 } 75 76 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 77 unsigned long key) 78 { 79 struct drm_hash_item *entry; 80 struct hlist_head *h_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_entry(entry, h_list, head) { 86 if (entry->key == key) 87 return &entry->head; 88 if (entry->key > key) 89 break; 90 } 91 return NULL; 92 } 93 94 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 95 unsigned long key) 96 { 97 struct drm_hash_item *entry; 98 struct hlist_head *h_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, h_list, head) { 104 if (entry->key == key) 105 return &entry->head; 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 *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, h_list, head) { 124 if (entry->key == key) 125 return -EINVAL; 126 if (entry->key > key) 127 break; 128 parent = &entry->head; 129 } 130 if (parent) { 131 hlist_add_behind_rcu(&item->head, parent); 132 } else { 133 hlist_add_head_rcu(&item->head, h_list); 134 } 135 return 0; 136 } 137 138 /* 139 * Just insert an item and return any "bits" bit key that hasn't been 140 * used before. 141 */ 142 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 143 unsigned long seed, int bits, int shift, 144 unsigned long add) 145 { 146 int ret; 147 unsigned long mask = (1UL << bits) - 1; 148 unsigned long first, unshifted_key; 149 150 unshifted_key = hash_long(seed, bits); 151 first = unshifted_key; 152 do { 153 item->key = (unshifted_key << shift) + add; 154 ret = drm_ht_insert_item(ht, item); 155 if (ret) 156 unshifted_key = (unshifted_key + 1) & mask; 157 } while(ret && (unshifted_key != first)); 158 159 if (ret) { 160 DRM_ERROR("Available key bit space exhausted\n"); 161 return -EINVAL; 162 } 163 return 0; 164 } 165 166 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 167 struct drm_hash_item **item) 168 { 169 struct hlist_node *list; 170 171 list = drm_ht_find_key_rcu(ht, key); 172 if (!list) 173 return -EINVAL; 174 175 *item = hlist_entry(list, struct drm_hash_item, head); 176 return 0; 177 } 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 } 196 197 void drm_ht_remove(struct drm_open_hash *ht) 198 { 199 if (ht->table) { 200 kvfree(ht->table); 201 ht->table = NULL; 202 } 203 } 204