urcu/rcuja.h

   1 #ifndef _URCU_RCUJA_H
   2 #define _URCU_RCUJA_H
   3
   4 /*
   5  * urcu/rcuja.h
   6  *
   7  * Userspace RCU library - RCU Judy Array
   8  *
   9  * Copyright 2012 - 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  * Include this file _after_ including your URCU flavor.
  26  */
  27
  28 #include <stdint.h>
  29 #include <urcu/compiler.h>
  30 #include <urcu-call-rcu.h>
  31 #include <urcu-flavor.h>
  32 #include <stdint.h>
  33 #include <urcu/rcuhlist.h>
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 /*
  40  * Duplicate nodes with the same key are chained into a singly-linked
  41  * list. The last item of this list has a NULL next pointer.
  42  */
  43 struct cds_ja_node {
  44         struct cds_ja_node *next;
  45 };
  46
  47 struct cds_ja;
  48
  49 /*
  50  * cds_ja_node_init - initialize a judy array node
  51  * @node: the node to initialize.
  52  *
  53  * This function is kept to be eventually used for debugging purposes
  54  * (detection of memory corruption).
  55  */
  56 static inline
  57 void cds_ja_node_init(struct cds_ja_node *node)
  58 {
  59 }
  60
  61 /*
  62  * cds_ja_lookup - look up by key.
  63  * @ja: the Judy array.
  64  * @key: key to look up.
  65  *
  66  * Returns the first node of a duplicate chain if a match is found, else
  67  * returns NULL.
  68  * A RCU read-side lock should be held across call to this function and
  69  * use of its return value.
  70  */
  71 struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key);
  72
  73 /*
  74  * cds_ja_lookup_below_equal - look up first node with key <= @key.
  75  * @ja: the Judy array.
  76  * @key: key to look up.
  77  *
  78  * Returns the first node of a duplicate chain if a node is present in
  79  * the tree which has a key below or equal to @key, else returns NULL.
  80  * A RCU read-side lock should be held across call to this function and
  81  * use of its return value.
  82  */
  83 struct cds_ja_node *cds_ja_lookup_below_equal(struct cds_ja *ja,
  84                 uint64_t key);
  85
  86 /*
  87  * cds_ja_lookup_above_equal - look up first node with key >= @key.
  88  * @ja: the Judy array.
  89  * @key: key to look up.
  90  *
  91  * Returns the first node of a duplicate chain if a node is present in
  92  * the tree which has a key above or equal to @key, else returns NULL.
  93  * A RCU read-side lock should be held across call to this function and
  94  * use of its return value.
  95  */
  96 struct cds_ja_node *cds_ja_lookup_above_equal(struct cds_ja *ja,
  97                 uint64_t key);
  98
  99 /*
 100  * cds_ja_add - Add @node at @key, allowing duplicates.
 101  * @ja: the Judy array.
 102  * @key: key at which @node should be added.
 103  * @node: node to add.
 104  *
 105  * Returns 0 on success, negative error value on error.
 106  * A RCU read-side lock should be held across call to this function.
 107  */
 108 int cds_ja_add(struct cds_ja *ja, uint64_t key,
 109                 struct cds_ja_node *node);
 110
 111 /*
 112  * cds_ja_add_unique - Add @node at @key, without duplicates.
 113  * @ja: the Judy array.
 114  * @key: key at which @node should be added.
 115  * @node: node to add.
 116  *
 117  * Returns @node if successfully added, else returns the already
 118  * existing node (acts as a RCU lookup).
 119  * A RCU read-side lock should be held across call to this function and
 120  * use of its return value.
 121  */
 122 struct cds_ja_node *cds_ja_add_unique(struct cds_ja *ja, uint64_t key,
 123                 struct cds_ja_node *node);
 124
 125 /*
 126  * cds_ja_del - Remove @node at @key.
 127  * @ja: the Judy array.
 128  * @key: key at which @node is expected.
 129  * @node: node to remove.
 130  *
 131  * Returns 0 on success, negative error value on error.
 132  * A RCU read-side lock should be held across call to this function.
 133  */
 134 int cds_ja_del(struct cds_ja *ja, uint64_t key,
 135                 struct cds_ja_node *node);
 136
 137 struct cds_ja *_cds_ja_new(unsigned int key_bits,
 138                 const struct rcu_flavor_struct *flavor);
 139
 140 /*
 141  * cds_ja_new - Create a Judy array.
 142  * @key_bits: Number of bits for key.
 143  *
 144  * Returns non-NULL pointer on success, else NULL on error. @key_bits
 145  * needs to be multiple of 8, either: 8, 16, 24, 32, 40, 48, 56, or 64.
 146  */
 147 static inline
 148 struct cds_ja *cds_ja_new(unsigned int key_bits)
 149 {
 150         return _cds_ja_new(key_bits, &rcu_flavor);
 151 }
 152
 153 /*
 154  * cds_ja_destroy - Destroy a Judy array.
 155  * @ja: the Judy array.
 156  * @rcu_free_node_cb: callback performing memory free of leftover nodes.
 157  *
 158  * Returns 0 on success, negative error value on error.
 159  * There should be no more concurrent add, delete, nor look-up performed
 160  * on the Judy array while it is being destroyed (ensured by the caller).
 161  * There is no need for the @rcu_free_node_cb callback to wait for grace
 162  * periods, since there are no more concurrent users of the Judy array.
 163  * RCU read-side lock should _not_ be held when calling this function,
 164  * however, QSBR threads need to be online.
 165  */
 166 int cds_ja_destroy(struct cds_ja *ja,
 167                 void (*free_node_cb)(struct cds_ja_node *node));
 168
 169 /*
 170  * Iterate through duplicates returned by cds_ja_lookup*()
 171  * This must be done while rcu_read_lock() is held.
 172  * Receives a struct cds_ja_node * as parameter, which is used as start
 173  * of duplicate list and loop cursor.
 174  */
 175 #define cds_ja_for_each_duplicate_rcu(pos)                              \
 176         for (; (pos) != NULL; (pos) = rcu_dereference((pos)->next))
 177
 178 #ifdef __cplusplus
 179 }
 180 #endif
 181
 182 #endif /* _URCU_RCUJA_H */