1 files changed, 91 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/BLI_linklist_lockfree.c b/source/blender/blenlib/intern/BLI_linklist_lockfree.c
new file mode 100644
index 00000000000..c004ddb6b66
--- /dev/null
+++ b/source/blender/blenlib/intern/BLI_linklist_lockfree.c
@@ -0,0 +1,91 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2018 Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Sergey Sharybin.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/blenlib/intern/BLI_linklist_lockfree.c
+ *  \ingroup bli
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_linklist_lockfree.h"
+#include "BLI_strict_flags.h"
+
+#include "atomic_ops.h"
+
+void BLI_linklist_lockfree_init(LockfreeLinkList *list)
+{
+	list->dummy_node.next = NULL;
+	list->head = list->tail = &list->dummy_node;
+}
+
+void BLI_linklist_lockfree_free(LockfreeLinkList *list,
+                                LockfreeeLinkNodeFreeFP free_func)
+{
+	if (free_func != NULL) {
+		/* NOTE: We start from a first user-added node. */
+		LockfreeLinkNode *node = list->head->next;
+		while (node != NULL) {
+			LockfreeLinkNode *node_next = node->next;
+			free_func(node);
+			node = node_next;
+		}
+	}
+}
+
+void BLI_linklist_lockfree_clear(LockfreeLinkList *list,
+                                 LockfreeeLinkNodeFreeFP free_func)
+{
+	BLI_linklist_lockfree_free(list, free_func);
+	BLI_linklist_lockfree_init(list);
+}
+
+void BLI_linklist_lockfree_insert(LockfreeLinkList *list,
+                                  LockfreeLinkNode *node)
+{
+	/* Based on:
+	 *
+	 *   John D. Valois
+	 *   Implementing Lock-Free Queues
+	 *
+	 *   http://people.csail.mit.edu/bushl2/rpi/portfolio/lockfree-grape/documents/lock-free-linked-lists.pdf
+	 */
+	bool keep_working;
+	LockfreeLinkNode *tail_node;
+	node->next = NULL;
+	do {
+		tail_node = list->tail;
+		keep_working =
+			(atomic_cas_ptr((void**)&tail_node->next, NULL, node) != NULL);
+		if (keep_working) {
+			atomic_cas_ptr((void**)&list->tail, tail_node, tail_node->next);
+		}
+	} while (keep_working);
+	atomic_cas_ptr((void**)&list->tail, tail_node, node);
+}
+
+LockfreeLinkNode *BLI_linklist_lockfree_begin(LockfreeLinkList *list)
+{
+	return list->head->next;
+}