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 <stdint.h>
  29 #include <urcu/compiler.h>
  30 #include <urcu-call-rcu.h>
  31 #include <urcu-flavor.h>
  32 #include <stdint.h>
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 /*
  39  * Duplicate nodes with the same key are chained into a singly-linked
  40  * list. The last item of this list has a NULL next pointer.
  41  */
  42 struct cds_ja_node {
  43         struct cds_ja_node *next;
  44 };
  45
  46 struct cds_ja;
  47
  48 /*
  49  * cds_ja_node_init - initialize a judy array node
  50  * @node: the node to initialize.
  51  *
  52  * This function is kept to be eventually used for debugging purposes
  53  * (detection of memory corruption).
  54  */
  55 static inline
  56 void cds_ja_node_init(struct cds_ja_node *node)
  57 {
  58 }
  59
  60 /*
  61  * cds_ja_lookup - look up by key.
  62  * @ja: the Judy array.
  63  * @key: key to look up.
  64  *
  65  * Returns the first node of a duplicate chain if a match is found, else
  66  * returns NULL.
  67  * A RCU read-side lock should be held across call to this function and
  68  * use of its return value.
  69  */
  70 struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key);
  71
  72 /*
  73  * cds_ja_lookup_below_equal - look up first node with key <= @key.
  74  * @ja: the Judy array.
  75  * @key: key to look up.
  76  * @result_key: key found.
  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, uint64_t *result_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  * @result_key: key found.
  91  *
  92  * Returns the first node of a duplicate chain if a node is present in
  93  * the tree which has a key above or equal to @key, else returns NULL.
  94  * A RCU read-side lock should be held across call to this function and
  95  * use of its return value.
  96  */
  97 struct cds_ja_node *cds_ja_lookup_above_equal(struct cds_ja *ja,
  98                 uint64_t key, uint64_t *result_key);
  99
 100 /*
 101  * cds_ja_add - Add @node at @key, allowing duplicates.
 102  * @ja: the Judy array.
 103  * @key: key at which @node should be added.
 104  * @node: node to add.
 105  *
 106  * Returns 0 on success, negative error value on error.
 107  * A RCU read-side lock should be held across call to this function.
 108  */
 109 int cds_ja_add(struct cds_ja *ja, uint64_t key,
 110                 struct cds_ja_node *node);
 111
 112 /*
 113  * cds_ja_add_unique - Add @node at @key, without duplicates.
 114  * @ja: the Judy array.
 115  * @key: key at which @node should be added.
 116  * @node: node to add.
 117  *
 118  * Returns @node if successfully added, else returns the already
 119  * existing node (acts as a RCU lookup).
 120  * A RCU read-side lock should be held across call to this function and
 121  * use of its return value.
 122  */
 123 struct cds_ja_node *cds_ja_add_unique(struct cds_ja *ja, uint64_t key,
 124                 struct cds_ja_node *node);
 125
 126 /*
 127  * cds_ja_del - Remove @node at @key.
 128  * @ja: the Judy array.
 129  * @key: key at which @node is expected.
 130  * @node: node to remove.
 131  *
 132  * Returns 0 on success, negative error value on error.
 133  * A RCU read-side lock should be held across call to this function.
 134  */
 135 int cds_ja_del(struct cds_ja *ja, uint64_t key,
 136                 struct cds_ja_node *node);
 137
 138 struct cds_ja *_cds_ja_new(unsigned int key_bits,
 139                 const struct rcu_flavor_struct *flavor);
 140
 141 /*
 142  * cds_ja_new - Create a Judy array.
 143  * @key_bits: Number of bits for key.
 144  *
 145  * Returns non-NULL pointer on success, else NULL on error. @key_bits
 146  * needs to be multiple of 8, either: 8, 16, 24, 32, 40, 48, 56, or 64.
 147  */
 148 static inline
 149 struct cds_ja *cds_ja_new(unsigned int key_bits)
 150 {
 151         return _cds_ja_new(key_bits, &rcu_flavor);
 152 }
 153
 154 /*
 155  * cds_ja_destroy - Destroy a Judy array.
 156  * @ja: the Judy array.
 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  * RCU read-side lock should _not_ be held when calling this function,
 162  * however, QSBR threads need to be online.
 163  */
 164 int cds_ja_destroy(struct cds_ja *ja);
 165
 166 /*
 167  * cds_ja_for_each_duplicate_rcu: Iterate through duplicates.
 168  * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
 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  * _NOT_ safe against node removal within iteration.
 175  */
 176 #define cds_ja_for_each_duplicate_rcu(pos)                                      \
 177         for (; (pos) != NULL; (pos) = rcu_dereference((pos)->next))
 178
 179 /*
 180  * cds_ja_for_each_duplicate_safe: Iterate through duplicates.
 181  * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
 182  * @p: struct cds_ja_node *, temporary pointer to next.
 183  *
 184  * Iterate through duplicates returned by cds_ja_lookup*().
 185  * Safe against node removal within iteration.
 186  * This must be done while rcu_read_lock() is held.
 187  */
 188 #define cds_ja_for_each_duplicate_safe_rcu(pos, p)                      \
 189         for (; (pos) != NULL ?                                          \
 190                         ((p) = rcu_dereference((pos)->next), 1) : 0;    \
 191                         (pos) = (p))
 192
 193 /*
 194  * cds_ja_for_each_key_rcu: Iterate over all keys in ascending order.
 195  * @ja: Judy array on which iteration should be done.
 196  * @key: Key cursor, needs to be a uint64_t.
 197  * @pos: struct cds_ja_node *, used as loop cursor.
 198  *
 199  * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
 200  * ascending order.
 201  * This must be done while rcu_read_lock() is held.
 202  * Safe against node removal during iteration.
 203  */
 204 #define cds_ja_for_each_key_rcu(ja, key, pos)                           \
 205         for ((key) = 0;                                                 \
 206                 ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))); )
 207
 208 /*
 209  * cds_ja_for_each_key_prev_rcu: Iterate over all keys in descending order.
 210  * @ja: Judy array on which iteration should be done.
 211  * @key: Key cursor, needs to be a uint64_t.
 212  * @pos: struct cds_ja_node *, used as loop cursor.
 213  *
 214  * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
 215  * descending order.
 216  * This must be done while rcu_read_lock() is held.
 217  * Safe against node removal during iteration.
 218  */
 219 #define cds_ja_for_each_key_prev_rcu(ja, key, pos)                      \
 220         for ((key) = UINT64_MAX;                                        \
 221                 ((pos) = cds_ja_lookup_below_equal(ja, key, &(key))); )
 222
 223 #ifdef __cplusplus
 224 }
 225 #endif
 226
 227 #endif /* _URCU_RCUJA_H */