linux/lib/plist.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * lib/plist.c
 *
 * Descending-priority-sorted double-linked list
 *
 * (C) 2002-2003 Intel Corp
 * Inaky Perez-Gonzalez <[email protected]>.
 *
 * 2001-2005 (c) MontaVista Software, Inc.
 * Daniel Walker <[email protected]>
 *
 * (C) 2005 Thomas Gleixner <[email protected]>
 *
 * Simplifications of the original code by
 * Oleg Nesterov <[email protected]>
 *
 * Based on simple lists (include/linux/list.h).
 *
 * This file contains the add / del functions which are considered to
 * be too large to inline. See include/linux/plist.h for further
 * information.
 */

#include <linux/bug.h>
#include <linux/plist.h>

#ifdef CONFIG_DEBUG_PLIST

static struct plist_head test_head;

static void plist_check_prev_next(struct list_head *t, struct list_head *p,
				  struct list_head *n)
{ … }

static void plist_check_list(struct list_head *top)
{ … }

static void plist_check_head(struct plist_head *head)
{ … }

#else
#define plist_check_head …
#endif

/**
 * plist_add - add @node to @head
 *
 * @node:	&struct plist_node pointer
 * @head:	&struct plist_head pointer
 */
void plist_add(struct plist_node *node, struct plist_head *head)
{ … }

/**
 * plist_del - Remove a @node from plist.
 *
 * @node:	&struct plist_node pointer - entry to be removed
 * @head:	&struct plist_head pointer - list head
 */
void plist_del(struct plist_node *node, struct plist_head *head)
{ … }

/**
 * plist_requeue - Requeue @node at end of same-prio entries.
 *
 * This is essentially an optimized plist_del() followed by
 * plist_add().  It moves an entry already in the plist to
 * after any other same-priority entries.
 *
 * @node:	&struct plist_node pointer - entry to be moved
 * @head:	&struct plist_head pointer - list head
 */
void plist_requeue(struct plist_node *node, struct plist_head *head)
{ … }

#ifdef CONFIG_DEBUG_PLIST
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/module.h>
#include <linux/init.h>

static struct plist_node __initdata test_node[241];

static void __init plist_test_check(int nr_expect)
{ … }

static void __init plist_test_requeue(struct plist_node *node)
{ … }

static int  __init plist_test(void)
{ … }

module_init(…) …;

#endif