From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 10 Jan 2022 20:35:53 +0000 (-0500)
Subject: rculfhash: introduce cds_lfht_node_init_deleted
X-Git-Tag: v0.14.0~38
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=4c10e9af6fb29192621372ab9077860f3c1b179f;p=userspace-rcu.git

rculfhash: introduce cds_lfht_node_init_deleted

Allow initializing lfht node to "removed" state to allow querying
whether the node is published in a hash table before it is added to the
hash table and after it has been removed from the hash table.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I6e364a3ea076f33e34b4c63c7b23be22b35e9bb1
---

diff --git a/include/urcu/rculfhash.h b/include/urcu/rculfhash.h
index 29dd88f..8586e1d 100644
--- a/include/urcu/rculfhash.h
+++ b/include/urcu/rculfhash.h
@@ -109,6 +109,16 @@ void cds_lfht_node_init(struct cds_lfht_node *node __attribute__((unused)))
 {
 }
 
+/*
+ * cds_lfht_node_init_deleted - initialize a hash table node to "removed" state
+ * @node: the node to initialize.
+ *
+ * Initialize the node such that cds_lfht_is_node_deleted() can be used
+ * on the node before it is added to a hash table.
+ */
+extern
+void cds_lfht_node_init_deleted(struct cds_lfht_node *node);
+
 /*
  * Hash table creation flags.
  */
diff --git a/src/rculfhash.c b/src/rculfhash.c
index 04fd499..8046f3a 100644
--- a/src/rculfhash.c
+++ b/src/rculfhash.c
@@ -851,6 +851,12 @@ int is_removal_owner(struct cds_lfht_node *node)
 	return ((unsigned long) node) & REMOVAL_OWNER_FLAG;
 }
 
+static
+struct cds_lfht_node *flag_removed(struct cds_lfht_node *node)
+{
+	return (struct cds_lfht_node *) (((unsigned long) node) | REMOVED_FLAG);
+}
+
 static
 struct cds_lfht_node *flag_removal_owner(struct cds_lfht_node *node)
 {
@@ -1578,6 +1584,12 @@ const struct cds_lfht_mm_type *get_mm_type(
 }
 #endif
 
+void cds_lfht_node_init_deleted(struct cds_lfht_node *node)
+{
+	cds_lfht_node_init(node);
+	node->next = flag_removed(NULL);
+}
+
 struct cds_lfht *_cds_lfht_new(unsigned long init_size,
 			unsigned long min_nr_alloc_buckets,
 			unsigned long max_nr_buckets,