X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=doc%2Fexamples%2Flist%2Fcds_list_for_each_entry_rcu.c;fp=doc%2Fexamples%2Flist%2Fcds_list_for_each_entry_rcu.c;h=b0aff29c1d012d2162724955fd84e89fe7cbdfed;hp=0000000000000000000000000000000000000000;hb=d427bff9f837b32b4f7cd000078ed43cc0929a73;hpb=7eba9f8868d01401bc9b09ab2764bd371b783ad1 diff --git a/doc/examples/list/cds_list_for_each_entry_rcu.c b/doc/examples/list/cds_list_for_each_entry_rcu.c new file mode 100644 index 0000000..b0aff29 --- /dev/null +++ b/doc/examples/list/cds_list_for_each_entry_rcu.c @@ -0,0 +1,84 @@ +/* + * Copyright (C) 2013 Mathieu Desnoyers + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program for any + * purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is + * granted, provided the above notices are retained, and a notice that + * the code was modified is included with the above copyright notice. + * + * This example shows how to to a RCU linked list traversal, safely + * against concurrent RCU updates. + */ + +#include + +#include /* Userspace RCU flavor */ +#include /* RCU list */ +#include /* For CAA_ARRAY_SIZE */ + +/* + * Nodes populated into the list. + */ +struct mynode { + int value; /* Node content */ + struct cds_list_head node; /* Linked-list chaining */ +}; + +int main(int argc, char **argv) +{ + int values[] = { -5, 42, 36, 24, }; + CDS_LIST_HEAD(mylist); /* Defines an empty list head */ + unsigned int i; + int ret = 0; + struct mynode *node; + + /* + * Each thread need using RCU read-side need to be explicitely + * registered. + */ + rcu_register_thread(); + + /* + * Adding nodes to the linked-list. Safe against concurrent + * RCU traversals, require mutual exclusion with list updates. + */ + for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { + node = malloc(sizeof(*node)); + if (!node) { + ret = -1; + goto end; + } + node->value = values[i]; + cds_list_add_tail_rcu(&node->node, &mylist); + } + + /* + * RCU-safe iteration on the list. + */ + printf("mylist content:"); + + /* + * Surround the RCU read-side critical section with rcu_read_lock() + * and rcu_read_unlock(). + */ + rcu_read_lock(); + + /* + * This traversal can be performed concurrently with RCU + * updates. + */ + cds_list_for_each_entry_rcu(node, &mylist, node) { + printf(" %d", node->value); + } + + rcu_read_unlock(); + + printf("\n"); +end: + rcu_unregister_thread(); + return ret; +}