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 2012-2013 - 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 <urcu/compiler.h>
  29 #include <urcu-call-rcu.h>
  30 #include <urcu-flavor.h>
  31 #include <stdint.h>
  32
  33 #ifdef __cplusplus
  34 extern "C" {
  35 #endif
  36
  37 /*
  38  * Duplicate nodes with the same key are chained into a singly-linked
  39  * list. The last item of this list has a NULL next pointer.
  40  */
  41 struct cds_ja_node {
  42         struct cds_ja_node *next;
  43 };
  44
  45 struct cds_ja;
  46
  47 /*
  48  * cds_ja_node_init - initialize a judy array node
  49  * @node: the node to initialize.
  50  *
  51  * This function is kept to be eventually used for debugging purposes
  52  * (detection of memory corruption).
  53  */
  54 static inline
  55 void cds_ja_node_init(struct cds_ja_node *node)
  56 {
  57 }
  58
  59 /*
  60  * cds_ja_lookup - look up by key.
  61  * @ja: the Judy array.
  62  * @key: key to look up.
  63  *
  64  * Returns the first node of a duplicate chain if a match is found, else
  65  * returns NULL.
  66  * A RCU read-side lock should be held across call to this function and
  67  * use of its return value.
  68  */
  69 struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key);
  70
  71 /*
  72  * cds_ja_lookup_below_equal - look up first node with key <= @key.
  73  * @ja: the Judy array.
  74  * @key: key to look up.
  75  * @result_key: key found.
  76  *
  77  * Returns the first node of a duplicate chain if a node is present in
  78  * the tree which has a key below or equal to @key, else returns NULL.
  79  * A RCU read-side lock should be held across call to this function and
  80  * use of its return value.
  81  */
  82 struct cds_ja_node *cds_ja_lookup_below_equal(struct cds_ja *ja,
  83                 uint64_t key, uint64_t *result_key);
  84
  85 /*
  86  * cds_ja_lookup_above_equal - look up first node with key >= @key.
  87  * @ja: the Judy array.
  88  * @key: key to look up.
  89  * @result_key: key found.
  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, uint64_t *result_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  *
 157  * Returns 0 on success, negative error value on error.
 158  * There should be no more concurrent add, delete, nor look-up performed
 159  * on the Judy array while it is being destroyed (ensured by the caller).
 160  * RCU read-side lock should _not_ be held when calling this function,
 161  * however, QSBR threads need to be online.
 162  */
 163 int cds_ja_destroy(struct cds_ja *ja);
 164
 165 /*
 166  * cds_ja_for_each_duplicate_rcu: Iterate through duplicates.
 167  * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
 168  *
 169  * Iterate through duplicates returned by cds_ja_lookup*()
 170  * This must be done while rcu_read_lock() is held.
 171  * Receives a struct cds_ja_node * as parameter, which is used as start
 172  * of duplicate list and loop cursor.
 173  * _NOT_ safe against node removal within iteration.
 174  */
 175 #define cds_ja_for_each_duplicate_rcu(pos)                                      \
 176         for (; (pos) != NULL; (pos) = rcu_dereference((pos)->next))
 177
 178 /*
 179  * cds_ja_for_each_duplicate_safe: Iterate through duplicates.
 180  * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
 181  * @p: struct cds_ja_node *, temporary pointer to next.
 182  *
 183  * Iterate through duplicates returned by cds_ja_lookup*().
 184  * Safe against node removal within iteration.
 185  * This must be done while rcu_read_lock() is held.
 186  */
 187 #define cds_ja_for_each_duplicate_safe_rcu(pos, p)                      \
 188         for (; (pos) != NULL ?                                          \
 189                         ((p) = rcu_dereference((pos)->next), 1) : 0;    \
 190                         (pos) = (p))
 191
 192 /*
 193  * cds_ja_for_each_key_rcu: Iterate over all keys in ascending order.
 194  * @ja: Judy array on which iteration should be done.
 195  * @key: Key cursor, needs to be a uint64_t.
 196  * @pos: struct cds_ja_node *, used as loop cursor.
 197  *
 198  * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
 199  * ascending order.
 200  * This must be done while rcu_read_lock() is held.
 201  * Safe against node removal during iteration.
 202  */
 203 #define cds_ja_for_each_key_rcu(ja, key, pos)                           \
 204         for ((key) = 0;                                                 \
 205                 ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))); )
 206
 207 /*
 208  * cds_ja_for_each_key_prev_rcu: Iterate over all keys in descending order.
 209  * @ja: Judy array on which iteration should be done.
 210  * @key: Key cursor, needs to be a uint64_t.
 211  * @pos: struct cds_ja_node *, used as loop cursor.
 212  *
 213  * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
 214  * descending order.
 215  * This must be done while rcu_read_lock() is held.
 216  * Safe against node removal during iteration.
 217  */
 218 #define cds_ja_for_each_key_prev_rcu(ja, key, pos)                      \
 219         for ((key) = UINT64_MAX;                                        \
 220                 ((pos) = cds_ja_lookup_below_equal(ja, key, &(key))); )
 221
 222 #ifdef __cplusplus
 223 }
 224 #endif
 225
 226 #endif /* _URCU_RCUJA_H */