/**
 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
 * @pos:        the type * to use as a start point
 * @head:       the head of the list
 * @member:     the name of the list_head within the struct.
 *
 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
 */
#define list_prepare_entry(pos, head, member) \
        ((pos) ? : list_entry(head, typeof(*pos), member))

/*
 * bindirect-list
 *
 * (C) 20179.04.25 <buddy.zhang@aliyun.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*
 * bidirect-list
 *
 * +-----------+<--o    +-----------+<--o    +-----------+<--o    +-----------+
 * |           |   |    |           |   |    |           |   |    |           |
 * |      prev |   o----| prev      |   o----| prev      |   o----| prev      |
 * | list_head |        | list_head |        | list_head |        | list_head |
 * |      next |---o    |      next |---o    |      next |---o    |      next |
 * |           |   |    |           |   |    |           |   |    |           |
 * +-----------+   o--->+-----------+   o--->+-----------+   o--->+-----------+
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>

/* header of list */
#include <linux/list.h>

/* private structure */
struct node {
    const char *name;
    struct list_head list;
};

/* Initialize a group node structure */
static struct node node0 = { .name = "BiscuitOS_node0", };
static struct node node1 = { .name = "BiscuitOS_node1", };
static struct node node2 = { .name = "BiscuitOS_node2", };
static struct node node3 = { .name = "BiscuitOS_node3", };
static struct node node4 = { .name = "BiscuitOS_node4", };
static struct node node5 = { .name = "BiscuitOS_node5", };
static struct node node6 = { .name = "BiscuitOS_node6", };

/* Declaration and implement a bindirect-list */
LIST_HEAD(BiscuitOS_list);

static __init int bindirect_demo_init(void)
{
	struct node *np;
	struct node *np2;

	/* add a new entry on special entry */
	list_add_tail(&node0.list, &BiscuitOS_list);
	list_add_tail(&node1.list, &BiscuitOS_list);
	list_add_tail(&node2.list, &BiscuitOS_list);
	list_add_tail(&node3.list, &BiscuitOS_list);
	list_add_tail(&node4.list, &BiscuitOS_list);
	list_add_tail(&node5.list, &BiscuitOS_list);
	list_add_tail(&node6.list, &BiscuitOS_list);

	printk("BiscuitOS_list:\n");
	/* Traverser all node on bindirect-list */
	list_for_each_entry(np, &BiscuitOS_list, list)
		printk("%s\n", np->name);

	np = NULL;
	/* prepare a pos entry */
	np2 = list_prepare_entry(np, &node0.list, list);
	printk("Prepare Null entry: %s\n", np2->name);

	np = &node2;
	/* prepare a pos exist entry. */
	np2 = list_prepare_entry(np, &node0.list, list);
	printk("Prepare exist entry: %s\n", np2->name);

	return 0;
}
device_initcall(bindirect_demo_init);

diff --git a/drivers/BiscuitOS/Kconfig b/drivers/BiscuitOS/Kconfig
index 4edc5a5..1a9abee 100644
--- a/drivers/BiscuitOS/Kconfig
+++ b/drivers/BiscuitOS/Kconfig
@@ -6,4 +6,14 @@ if BISCUITOS_DRV
config BISCUITOS_MISC
        bool "BiscuitOS misc driver"
+config BISCUITOS_LIST
+       bool "Bindirect-list"
+
+if BISCUITOS_LIST
+
+config DEBUG_BISCUITOS_LIST
+       bool "list_prepare_entry"
+
+endif # BISCUITOS_LIST
+
endif # BISCUITOS_DRV

diff --git a/drivers/BiscuitOS/Makefile b/drivers/BiscuitOS/Makefile
index 82004c9..9909149 100644
--- a/drivers/BiscuitOS/Makefile
+++ b/drivers/BiscuitOS/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_BISCUITOS_MISC)     += BiscuitOS_drv.o
+obj-$(CONFIG_BISCUITOS_LIST)    += list.o
--

Device Driver--->
    [*]BiscuitOS Driver--->
        [*]Bindirect-list
            [*]list_prepare_entry()