1 /* $NetBSD: drm_hashtab.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $ */ 2 3 /************************************************************************** 4 * 5 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA. 6 * All Rights Reserved. 7 * 8 * Permission is hereby granted, free of charge, to any person obtaining a 9 * copy of this software and associated documentation files (the 10 * "Software"), to deal in the Software without restriction, including 11 * without limitation the rights to use, copy, modify, merge, publish, 12 * distribute, sub license, and/or sell copies of the Software, and to 13 * permit persons to whom the Software is furnished to do so, subject to 14 * the following conditions: 15 * 16 * The above copyright notice and this permission notice (including the 17 * next paragraph) shall be included in all copies or substantial portions 18 * of the Software. 19 * 20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 23 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 24 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 25 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 26 * USE OR OTHER DEALINGS IN THE SOFTWARE. 27 * 28 * 29 **************************************************************************/ 30 /* 31 * Simple open hash tab implementation. 32 * 33 * Authors: 34 * Thomas Hellström <thomas-at-tungstengraphics-dot-com> 35 */ 36 37 #include <sys/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: drm_hashtab.c,v 1.3 2021/12/18 23:44:57 riastradh Exp $"); 39 40 #include <linux/export.h> 41 #include <linux/hash.h> 42 #include <linux/mm.h> 43 #include <linux/rculist.h> 44 #include <linux/slab.h> 45 #include <linux/vmalloc.h> 46 47 #include <drm/drm_hashtab.h> 48 #include <drm/drm_print.h> 49 50 int drm_ht_create(struct drm_open_hash *ht, unsigned int order) 51 { 52 unsigned int size = 1 << order; 53 54 ht->order = order; 55 ht->table = NULL; 56 if (size <= PAGE_SIZE / sizeof(*ht->table)) 57 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL); 58 else 59 ht->table = vzalloc(array_size(size, sizeof(*ht->table))); 60 if (!ht->table) { 61 DRM_ERROR("Out of memory for hash table\n"); 62 return -ENOMEM; 63 } 64 return 0; 65 } 66 EXPORT_SYMBOL(drm_ht_create); 67 68 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 69 { 70 struct drm_hash_item *entry; 71 struct hlist_head *h_list; 72 unsigned int hashed_key; 73 int count = 0; 74 75 hashed_key = hash_long(key, ht->order); 76 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 77 h_list = &ht->table[hashed_key]; 78 hlist_for_each_entry(entry, h_list, head) 79 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 80 } 81 82 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 83 unsigned long key) 84 { 85 struct drm_hash_item *entry; 86 struct hlist_head *h_list; 87 unsigned int hashed_key; 88 89 hashed_key = hash_long(key, ht->order); 90 h_list = &ht->table[hashed_key]; 91 hlist_for_each_entry(entry, h_list, head) { 92 if (entry->key == key) 93 return &entry->head; 94 if (entry->key > key) 95 break; 96 } 97 return NULL; 98 } 99 100 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 101 unsigned long key) 102 { 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 } 117 118 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 119 { 120 struct drm_hash_item *entry; 121 struct hlist_head *h_list; 122 struct hlist_node *parent; 123 unsigned int hashed_key; 124 unsigned long key = item->key; 125 126 hashed_key = hash_long(key, ht->order); 127 h_list = &ht->table[hashed_key]; 128 parent = NULL; 129 hlist_for_each_entry(entry, h_list, head) { 130 if (entry->key == key) 131 return -EINVAL; 132 if (entry->key > key) 133 break; 134 parent = &entry->head; 135 } 136 if (parent) { 137 hlist_add_behind_rcu(&item->head, parent); 138 } else { 139 hlist_add_head_rcu(&item->head, h_list); 140 } 141 return 0; 142 } 143 EXPORT_SYMBOL(drm_ht_insert_item); 144 145 /* 146 * Just insert an item and return any "bits" bit key that hasn't been 147 * used before. 148 */ 149 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 150 unsigned long seed, int bits, int shift, 151 unsigned long add) 152 { 153 int ret; 154 unsigned long mask = (1UL << bits) - 1; 155 unsigned long first, unshifted_key; 156 157 unshifted_key = hash_long(seed, bits); 158 first = unshifted_key; 159 do { 160 item->key = (unshifted_key << shift) + add; 161 ret = drm_ht_insert_item(ht, item); 162 if (ret) 163 unshifted_key = (unshifted_key + 1) & mask; 164 } while(ret && (unshifted_key != first)); 165 166 if (ret) { 167 DRM_ERROR("Available key bit space exhausted\n"); 168 return -EINVAL; 169 } 170 return 0; 171 } 172 EXPORT_SYMBOL(drm_ht_just_insert_please); 173 174 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 175 struct drm_hash_item **item) 176 { 177 struct hlist_node *list; 178 179 list = drm_ht_find_key_rcu(ht, key); 180 if (!list) 181 return -EINVAL; 182 183 *item = hlist_entry(list, struct drm_hash_item, head); 184 return 0; 185 } 186 EXPORT_SYMBOL(drm_ht_find_item); 187 188 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 189 { 190 struct hlist_node *list; 191 192 list = drm_ht_find_key(ht, key); 193 if (list) { 194 hlist_del_init_rcu(list); 195 return 0; 196 } 197 return -EINVAL; 198 } 199 200 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 201 { 202 hlist_del_init_rcu(&item->head); 203 return 0; 204 } 205 EXPORT_SYMBOL(drm_ht_remove_item); 206 207 void drm_ht_remove(struct drm_open_hash *ht) 208 { 209 if (ht->table) { 210 kvfree(ht->table); 211 ht->table = NULL; 212 } 213 } 214 EXPORT_SYMBOL(drm_ht_remove); 215