1 /* $NetBSD: drm_hashtab.c,v 1.2 2018/08/27 04:58:19 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 1.2 2018/08/27 04:58:19 riastradh Exp $"); 39 40 #include <drm/drmP.h> 41 #include <drm/drm_hashtab.h> 42 #include <linux/hash.h> 43 #include <linux/slab.h> 44 #include <linux/export.h> 45 46 int drm_ht_create(struct drm_open_hash *ht, unsigned int order) 47 { 48 unsigned int size = 1 << order; 49 50 ht->order = order; 51 ht->table = NULL; 52 if (size <= PAGE_SIZE / sizeof(*ht->table)) 53 ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL); 54 else 55 ht->table = vzalloc(size*sizeof(*ht->table)); 56 if (!ht->table) { 57 DRM_ERROR("Out of memory for hash table\n"); 58 return -ENOMEM; 59 } 60 return 0; 61 } 62 EXPORT_SYMBOL(drm_ht_create); 63 64 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) 65 { 66 struct drm_hash_item *entry; 67 struct hlist_head *h_list; 68 unsigned int hashed_key; 69 int count = 0; 70 71 hashed_key = hash_long(key, ht->order); 72 DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); 73 h_list = &ht->table[hashed_key]; 74 hlist_for_each_entry(entry, h_list, head) 75 DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); 76 } 77 78 static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, 79 unsigned long key) 80 { 81 struct drm_hash_item *entry; 82 struct hlist_head *h_list; 83 unsigned int hashed_key; 84 85 hashed_key = hash_long(key, ht->order); 86 h_list = &ht->table[hashed_key]; 87 hlist_for_each_entry(entry, h_list, head) { 88 if (entry->key == key) 89 return &entry->head; 90 if (entry->key > key) 91 break; 92 } 93 return NULL; 94 } 95 96 static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, 97 unsigned long key) 98 { 99 struct drm_hash_item *entry; 100 struct hlist_head *h_list; 101 unsigned int hashed_key; 102 103 hashed_key = hash_long(key, ht->order); 104 h_list = &ht->table[hashed_key]; 105 hlist_for_each_entry_rcu(entry, h_list, head) { 106 if (entry->key == key) 107 return &entry->head; 108 if (entry->key > key) 109 break; 110 } 111 return NULL; 112 } 113 114 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) 115 { 116 struct drm_hash_item *entry; 117 struct hlist_head *h_list; 118 struct hlist_node *parent; 119 unsigned int hashed_key; 120 unsigned long key = item->key; 121 122 hashed_key = hash_long(key, ht->order); 123 h_list = &ht->table[hashed_key]; 124 parent = NULL; 125 hlist_for_each_entry(entry, h_list, head) { 126 if (entry->key == key) 127 return -EINVAL; 128 if (entry->key > key) 129 break; 130 parent = &entry->head; 131 } 132 if (parent) { 133 hlist_add_behind_rcu(&item->head, parent); 134 } else { 135 hlist_add_head_rcu(&item->head, h_list); 136 } 137 return 0; 138 } 139 EXPORT_SYMBOL(drm_ht_insert_item); 140 141 /* 142 * Just insert an item and return any "bits" bit key that hasn't been 143 * used before. 144 */ 145 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, 146 unsigned long seed, int bits, int shift, 147 unsigned long add) 148 { 149 int ret; 150 unsigned long mask = (1 << bits) - 1; 151 unsigned long first, unshifted_key; 152 153 unshifted_key = hash_long(seed, bits); 154 first = unshifted_key; 155 do { 156 item->key = (unshifted_key << shift) + add; 157 ret = drm_ht_insert_item(ht, item); 158 if (ret) 159 unshifted_key = (unshifted_key + 1) & mask; 160 } while(ret && (unshifted_key != first)); 161 162 if (ret) { 163 DRM_ERROR("Available key bit space exhausted\n"); 164 return -EINVAL; 165 } 166 return 0; 167 } 168 EXPORT_SYMBOL(drm_ht_just_insert_please); 169 170 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, 171 struct drm_hash_item **item) 172 { 173 struct hlist_node *list; 174 175 list = drm_ht_find_key_rcu(ht, key); 176 if (!list) 177 return -EINVAL; 178 179 *item = hlist_entry(list, struct drm_hash_item, head); 180 return 0; 181 } 182 EXPORT_SYMBOL(drm_ht_find_item); 183 184 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) 185 { 186 struct hlist_node *list; 187 188 list = drm_ht_find_key(ht, key); 189 if (list) { 190 hlist_del_init_rcu(list); 191 return 0; 192 } 193 return -EINVAL; 194 } 195 196 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) 197 { 198 hlist_del_init_rcu(&item->head); 199 return 0; 200 } 201 EXPORT_SYMBOL(drm_ht_remove_item); 202 203 void drm_ht_remove(struct drm_open_hash *ht) 204 { 205 if (ht->table) { 206 if ((PAGE_SIZE / sizeof(*ht->table)) >> ht->order) 207 kfree(ht->table); 208 else 209 vfree(ht->table); 210 ht->table = NULL; 211 } 212 } 213 EXPORT_SYMBOL(drm_ht_remove); 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