| 1 | #ifndef _URCU_RCULFHASH_H |
| 2 | #define _URCU_RCULFHASH_H |
| 3 | |
| 4 | /* |
| 5 | * urcu/rculfhash.h |
| 6 | * |
| 7 | * Userspace RCU library - Lock-Free RCU Hash Table |
| 8 | * |
| 9 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 10 | * |
| 11 | * This library is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU Lesser General Public |
| 13 | * License as published by the Free Software Foundation; either |
| 14 | * version 2.1 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | * This library is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 19 | * Lesser General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU Lesser General Public |
| 22 | * License along with this library; if not, write to the Free Software |
| 23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 24 | */ |
| 25 | |
| 26 | #include <stdint.h> |
| 27 | #include <urcu-call-rcu.h> |
| 28 | |
| 29 | #ifdef __cplusplus |
| 30 | extern "C" { |
| 31 | #endif |
| 32 | |
| 33 | /* |
| 34 | * struct cds_lfht_node and struct _cds_lfht_node should be aligned on |
| 35 | * 4-bytes boundaries because the two lower bits are used as flags. |
| 36 | */ |
| 37 | |
| 38 | struct _cds_lfht_node { |
| 39 | struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ |
| 40 | unsigned long reverse_hash; |
| 41 | }; |
| 42 | |
| 43 | struct cds_lfht_node { |
| 44 | /* cache-hot for iteration */ |
| 45 | struct _cds_lfht_node p; /* needs to be first field */ |
| 46 | void *key; |
| 47 | unsigned int key_len; |
| 48 | /* cache-cold for iteration */ |
| 49 | struct rcu_head head; |
| 50 | }; |
| 51 | |
| 52 | struct cds_lfht; |
| 53 | |
| 54 | /* |
| 55 | * Caution ! |
| 56 | * Ensure reader and writer threads are registered as urcu readers. |
| 57 | */ |
| 58 | |
| 59 | typedef unsigned long (*cds_lfht_hash_fct)(void *key, size_t length, |
| 60 | unsigned long seed); |
| 61 | typedef unsigned long (*cds_lfht_compare_fct)(void *key1, size_t key1_len, |
| 62 | void *key2, size_t key2_len); |
| 63 | |
| 64 | /* |
| 65 | * cds_lfht_node_init - initialize a hash table node |
| 66 | */ |
| 67 | static inline |
| 68 | void cds_lfht_node_init(struct cds_lfht_node *node, void *key, |
| 69 | size_t key_len) |
| 70 | { |
| 71 | node->key = key; |
| 72 | node->key_len = key_len; |
| 73 | } |
| 74 | |
| 75 | /* |
| 76 | * Hash table creation flags. |
| 77 | */ |
| 78 | enum { |
| 79 | CDS_LFHT_AUTO_RESIZE = (1U << 0), |
| 80 | }; |
| 81 | |
| 82 | /* |
| 83 | * cds_lfht_new - allocate a hash table. |
| 84 | * |
| 85 | * init_size must be power of two. |
| 86 | * Return NULL on error. |
| 87 | */ |
| 88 | struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, |
| 89 | cds_lfht_compare_fct compare_fct, |
| 90 | unsigned long hash_seed, |
| 91 | unsigned long init_size, |
| 92 | int flags, |
| 93 | void (*cds_lfht_call_rcu)(struct rcu_head *head, |
| 94 | void (*func)(struct rcu_head *head)), |
| 95 | void (*cds_lfht_synchronize_rcu)(void), |
| 96 | void (*cds_lfht_rcu_read_lock)(void), |
| 97 | void (*cds_lfht_rcu_read_unlock)(void), |
| 98 | void (*cds_lfht_rcu_thread_offline)(void), |
| 99 | void (*cds_lfht_rcu_thread_online)(void)); |
| 100 | |
| 101 | /* |
| 102 | * cds_lfht_destroy - destroy a hash table. |
| 103 | * |
| 104 | * Return 0 on success, negative error value on error. |
| 105 | */ |
| 106 | int cds_lfht_destroy(struct cds_lfht *ht); |
| 107 | |
| 108 | /* |
| 109 | * cds_lfht_count_nodes - count the number of nodes in the hash table. |
| 110 | * |
| 111 | * Call with rcu_read_lock held. |
| 112 | */ |
| 113 | void cds_lfht_count_nodes(struct cds_lfht *ht, |
| 114 | unsigned long *count, |
| 115 | unsigned long *removed); |
| 116 | |
| 117 | /* |
| 118 | * cds_lfht_lookup - lookup a node by key. |
| 119 | * |
| 120 | * Return NULL if not found. |
| 121 | * Call with rcu_read_lock held. |
| 122 | */ |
| 123 | struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len); |
| 124 | |
| 125 | /* |
| 126 | * cds_lfht_next - get the next item with same key (after a lookup). |
| 127 | * |
| 128 | * Return NULL if no following node exists with same key. |
| 129 | * RCU read-side lock must be held across cds_lfht_lookup and cds_lfht_next calls, and also |
| 130 | * between cds_lfht_next calls using the node returned by a previous cds_lfht_next. |
| 131 | * Call with rcu_read_lock held. |
| 132 | */ |
| 133 | struct cds_lfht_node *cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_node *node); |
| 134 | |
| 135 | /* |
| 136 | * cds_lfht_add - add a node to the hash table. |
| 137 | * |
| 138 | * Call with rcu_read_lock held. |
| 139 | */ |
| 140 | void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node); |
| 141 | |
| 142 | /* |
| 143 | * cds_lfht_add_unique - add a node to hash table, if key is not present. |
| 144 | * |
| 145 | * Return the node added upon success. |
| 146 | * Return the unique node already present upon failure. If cds_lfht_add_unique fails, |
| 147 | * the node passed as parameter should be freed by the caller. |
| 148 | * Call with rcu_read_lock held. |
| 149 | */ |
| 150 | struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, struct cds_lfht_node *node); |
| 151 | |
| 152 | /* |
| 153 | * cds_lfht_remove - remove node from hash table. |
| 154 | * |
| 155 | * Node can be looked up with cds_lfht_lookup. RCU read-side lock must be held between |
| 156 | * lookup and removal. |
| 157 | * Call with rcu_read_lock held. |
| 158 | */ |
| 159 | int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node); |
| 160 | |
| 161 | /* |
| 162 | * cds_lfht_resize - Force a hash table resize |
| 163 | * @new_size: update to this hash table size. |
| 164 | */ |
| 165 | void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); |
| 166 | |
| 167 | #ifdef __cplusplus |
| 168 | } |
| 169 | #endif |
| 170 | |
| 171 | #endif /* _URCU_RCULFHASH_H */ |