7 * Userspace RCU library - RCU Judy Array
9 * Copyright 2012-2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
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
25 * Include this file _after_ including your URCU flavor.
28 #include <urcu/compiler.h>
29 #include <urcu-call-rcu.h>
30 #include <urcu-flavor.h>
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.
42 struct cds_ja_node
*next
;
48 * cds_ja_node_init - initialize a judy array node
49 * @node: the node to initialize.
51 * This function is kept to be eventually used for debugging purposes
52 * (detection of memory corruption).
55 void cds_ja_node_init(struct cds_ja_node
*node
)
60 * Note: key UINT64_MAX is reserved internally for iteration.
64 * cds_ja_lookup - look up by key.
65 * @ja: the Judy array.
66 * @key: key to look up.
68 * Returns the first node of a duplicate chain if a match is found, else
70 * A RCU read-side lock should be held across call to this function and
71 * use of its return value.
73 struct cds_ja_node
*cds_ja_lookup(struct cds_ja
*ja
, uint64_t key
);
76 * cds_ja_lookup_below_equal - look up first node with key <= @key.
77 * @ja: the Judy array.
78 * @key: key to look up.
79 * @result_key: key found.
81 * Returns the first node of a duplicate chain if a node is present in
82 * the tree which has a key below or equal to @key, else returns NULL.
83 * A RCU read-side lock should be held across call to this function and
84 * use of its return value.
86 struct cds_ja_node
*cds_ja_lookup_below_equal(struct cds_ja
*ja
,
87 uint64_t key
, uint64_t *result_key
);
90 * cds_ja_lookup_above_equal - look up first node with key >= @key.
91 * @ja: the Judy array.
92 * @key: key to look up.
93 * @result_key: key found.
95 * Returns the first node of a duplicate chain if a node is present in
96 * the tree which has a key above or equal to @key, else returns NULL.
97 * A RCU read-side lock should be held across call to this function and
98 * use of its return value.
100 struct cds_ja_node
*cds_ja_lookup_above_equal(struct cds_ja
*ja
,
101 uint64_t key
, uint64_t *result_key
);
104 * cds_ja_add - Add @node at @key, allowing duplicates.
105 * @ja: the Judy array.
106 * @key: key at which @node should be added.
107 * @node: node to add.
109 * Returns 0 on success, negative error value on error.
110 * A RCU read-side lock should be held across call to this function.
112 int cds_ja_add(struct cds_ja
*ja
, uint64_t key
,
113 struct cds_ja_node
*node
);
116 * cds_ja_add_unique - Add @node at @key, without duplicates.
117 * @ja: the Judy array.
118 * @key: key at which @node should be added.
119 * @node: node to add.
121 * Returns @node if successfully added, else returns the already
122 * existing node (acts as a RCU lookup).
123 * A RCU read-side lock should be held across call to this function and
124 * use of its return value.
126 struct cds_ja_node
*cds_ja_add_unique(struct cds_ja
*ja
, uint64_t key
,
127 struct cds_ja_node
*node
);
130 * cds_ja_del - Remove @node at @key.
131 * @ja: the Judy array.
132 * @key: key at which @node is expected.
133 * @node: node to remove.
135 * Returns 0 on success, negative error value on error.
136 * A RCU read-side lock should be held across call to this function.
138 int cds_ja_del(struct cds_ja
*ja
, uint64_t key
,
139 struct cds_ja_node
*node
);
141 struct cds_ja
*_cds_ja_new(unsigned int key_bits
,
142 const struct rcu_flavor_struct
*flavor
);
145 * cds_ja_new - Create a Judy array.
146 * @key_bits: Number of bits for key.
148 * Returns non-NULL pointer on success, else NULL on error. @key_bits
149 * needs to be multiple of 8, either: 8, 16, 24, 32, 40, 48, 56, or 64.
152 struct cds_ja
*cds_ja_new(unsigned int key_bits
)
154 return _cds_ja_new(key_bits
, &rcu_flavor
);
158 * cds_ja_destroy - Destroy a Judy array.
159 * @ja: the Judy array.
161 * Returns 0 on success, negative error value on error.
162 * There should be no more concurrent add, delete, nor look-up performed
163 * on the Judy array while it is being destroyed (ensured by the caller).
164 * RCU read-side lock should _not_ be held when calling this function,
165 * however, QSBR threads need to be online.
167 int cds_ja_destroy(struct cds_ja
*ja
);
170 * cds_ja_for_each_duplicate_rcu: Iterate through duplicates.
171 * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
173 * Iterate through duplicates returned by cds_ja_lookup*()
174 * This must be done while rcu_read_lock() is held.
175 * Receives a struct cds_ja_node * as parameter, which is used as start
176 * of duplicate list and loop cursor.
177 * _NOT_ safe against node removal within iteration.
179 #define cds_ja_for_each_duplicate_rcu(pos) \
180 for (; (pos) != NULL; (pos) = rcu_dereference((pos)->next))
183 * cds_ja_for_each_duplicate_safe: Iterate through duplicates.
184 * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
185 * @p: struct cds_ja_node *, temporary pointer to next.
187 * Iterate through duplicates returned by cds_ja_lookup*().
188 * Safe against node removal within iteration.
189 * This must be done while rcu_read_lock() is held.
191 #define cds_ja_for_each_duplicate_safe_rcu(pos, p) \
192 for (; (pos) != NULL ? \
193 ((p) = rcu_dereference((pos)->next), 1) : 0; \
197 * cds_ja_for_each_key_rcu: Iterate over all keys in ascending order.
198 * @ja: Judy array on which iteration should be done.
199 * @key: Key cursor, needs to be a uint64_t.
200 * @pos: struct cds_ja_node *, used as loop cursor.
202 * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
204 * This must be done while rcu_read_lock() is held.
205 * Safe against node removal during iteration.
207 #define cds_ja_for_each_key_rcu(ja, key, pos) \
209 ((key) != UINT64_MAX ? \
210 ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))) : 0); \
214 * cds_ja_for_each_key_prev_rcu: Iterate over all keys in descending order.
215 * @ja: Judy array on which iteration should be done.
216 * @key: Key cursor, needs to be a uint64_t.
217 * @pos: struct cds_ja_node *, used as loop cursor.
219 * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
221 * This must be done while rcu_read_lock() is held.
222 * Safe against node removal during iteration.
224 #define cds_ja_for_each_key_prev_rcu(ja, key, pos) \
225 for ((key) = UINT64_MAX - 1; \
226 ((key) != UINT64_MAX ? \
227 ((pos) = cds_ja_lookup_below_equal(ja, key, &(key))) : 0); \
234 #endif /* _URCU_RCUJA_H */
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