tests: use SPDX identifiers
[urcu.git] / doc / examples / hlist / cds_hlist_del_rcu.c
CommitLineData
474190bf
MD
1/*
2 * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
3 *
4 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
5 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
6 *
7 * Permission is hereby granted to use or copy this program for any
8 * purpose, provided the above notices are retained on all copies.
9 * Permission to modify the code and to distribute modified code is
10 * granted, provided the above notices are retained, and a notice that
11 * the code was modified is included with the above copyright notice.
12 *
13 * This example shows how to remove from a non-circular linked-list
14 * safely against concurrent RCU traversals.
15 */
16
17#include <stdio.h>
18
b9050d91 19#include <urcu/urcu-memb.h> /* Userspace RCU flavor */
474190bf
MD
20#include <urcu/rcuhlist.h> /* RCU hlist */
21#include <urcu/compiler.h> /* For CAA_ARRAY_SIZE */
22
23/*
24 * Nodes populated into the list.
25 */
26struct mynode {
27 int value; /* Node content */
28 struct cds_hlist_node node; /* Linked-list chaining */
29 struct rcu_head rcu_head; /* For call_rcu() */
30};
31
32static
33void free_node_rcu(struct rcu_head *head)
34{
35 struct mynode *node = caa_container_of(head, struct mynode, rcu_head);
36
37 free(node);
38}
39
70469b43 40int main(void)
474190bf
MD
41{
42 int values[] = { -5, 42, 36, 24, };
43 CDS_HLIST_HEAD(mylist); /* Defines an empty hlist head */
44 unsigned int i;
45 int ret = 0;
46 struct mynode *node, *n;
47
48 /*
49 * Adding nodes to the linked-list. Safe against concurrent
50 * RCU traversals, require mutual exclusion with list updates.
51 */
52 for (i = 0; i < CAA_ARRAY_SIZE(values); i++) {
53 node = malloc(sizeof(*node));
54 if (!node) {
55 ret = -1;
56 goto end;
57 }
58 node->value = values[i];
59 cds_hlist_add_head_rcu(&node->node, &mylist);
60 }
61
62 /*
63 * Removing all positive values. Safe against concurrent RCU
64 * traversals, require mutual exclusion with list updates.
65 * Notice the "safe" iteration: it is safe against removal of
66 * nodes as we iterate on the list.
67 */
68 cds_hlist_for_each_entry_safe_2(node, n, &mylist, node) {
69 if (node->value > 0) {
70 cds_hlist_del_rcu(&node->node);
71 /*
72 * We can only reclaim memory after a grace
73 * period has passed after cds_hlist_del_rcu().
74 */
b9050d91 75 urcu_memb_call_rcu(&node->rcu_head, free_node_rcu);
474190bf
MD
76 }
77 }
78
79 /*
80 * Just show the list content. This is _not_ an RCU-safe
81 * iteration on the list.
82 */
83 printf("mylist content:");
84 cds_hlist_for_each_entry_2(node, &mylist, node) {
85 printf(" %d", node->value);
86 }
87 printf("\n");
88end:
89 return ret;
90}
This page took 0.040086 seconds and 4 git commands to generate.