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