qcacmn: Add APIs to split/join lists

Add following APIs.

  1. Split a list into 2 lists
  2. Join two lists

Change-Id: I9eb5cdfeeef582ef0bebe108f08fac307494b59d
CRs-Fixed: 3071041

qdf/inc/qdf_list.h

@@ -188,4 +188,31 @@ bool qdf_list_has_node(qdf_list_t *list, qdf_list_node_t *node);
  */
 bool qdf_list_node_in_any_list(const qdf_list_node_t *node);
 
+/**
+ * qdf_list_join - Join two lists and reinitialize the emptied list
+ * @list1: Pointer to list 1
+ * @list2: Pointer to list 2
+ *
+ * This API joins list1 and list2 and writes the resultant list (list1 + list2)
+ * to list1. list2 is re initialized to an empty list.
+ *
+ * Return: QDF_STATUS of operation
+ */
+QDF_STATUS qdf_list_join(qdf_list_t *list1, qdf_list_t *list2);
+
+/**
+ * qdf_list_split - Split a list into two chunks
+ * @new: Pointer to the list to store one of the chunks after splitting.
+ * This list will be overwritten by the API and hence it should be
+ * an empty list to avoid data loss.
+ * @list: Pointer to the list to be split
+ * @node: Pointer to a node within the @list. If @node is not present in
+ * the @list, behaviour is undefined.
+ *
+ * This API splits @list after @node. The initial portion of the @list
+ * up to and including @node will be moved to @new. The remaining portion will
+ * be assigned to @list.
+ */
+QDF_STATUS qdf_list_split(qdf_list_t *new, qdf_list_t *list,
+			  qdf_list_node_t *node);
 #endif /* __QDF_LIST_H */

qdf/linux/src/qdf_list.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2018 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014-2018, 2021 The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for
  * any purpose with or without fee is hereby granted, provided that the
@@ -262,3 +262,33 @@ bool qdf_list_node_in_any_list(const qdf_list_node_t *node)
 	return true;
 }
 
+QDF_STATUS qdf_list_split(qdf_list_t *new, qdf_list_t *list,
+			  qdf_list_node_t *node)
+{
+	qdf_list_node_t *cur_node;
+	uint32_t new_list_count = 0;
+
+	list_cut_position(&new->anchor, &list->anchor, node);
+
+	list_for_each(cur_node, &new->anchor)
+		new_list_count++;
+
+	new->count = new_list_count;
+	list->count = list->count - new->count;
+
+	return QDF_STATUS_SUCCESS;
+}
+
+qdf_export_symbol(qdf_list_split);
+
+QDF_STATUS qdf_list_join(qdf_list_t *list1, qdf_list_t *list2)
+{
+	list_splice_tail_init(&list2->anchor, &list1->anchor);
+
+	list1->count = list1->count + list2->count;
+	list2->count = 0;
+
+	return QDF_STATUS_SUCCESS;
+}
+
+qdf_export_symbol(qdf_list_join);