[thirdparty/linux.git] / lib / plist.c

/*
 * lib/plist.c
 *
 * Descending-priority-sorted double-linked list
 *
 * (C) 2002-2003 Intel Corp
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
 *
 * 2001-2005 (c) MontaVista Software, Inc.
 * Daniel Walker <dwalker@mvista.com>
 *
 * (C) 2005 Thomas Gleixner <tglx@linutronix.de>
 *
 * Simplifications of the original code by
 * Oleg Nesterov <oleg@tv-sign.ru>
 *
 * Licensed under the FSF's GNU Public License v2 or later.
 *
 * 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/plist.h>
#include <linux/spinlock.h>

#ifdef CONFIG_DEBUG_PI_LIST

static void plist_check_prev_next(struct list_head *t, struct list_head *p,
				  struct list_head *n)
{
	WARN(n->prev != p || p->next != n,
			"top: %p, n: %p, p: %p\n"
			"prev: %p, n: %p, p: %p\n"
			"next: %p, n: %p, p: %p\n",
			 t, t->next, t->prev,
			p, p->next, p->prev,
			n, n->next, n->prev);
}

static void plist_check_list(struct list_head *top)
{
	struct list_head *prev = top, *next = top->next;

	plist_check_prev_next(top, prev, next);
	while (next != top) {
		prev = next;
		next = prev->next;
		plist_check_prev_next(top, prev, next);
	}
}

static void plist_check_head(struct plist_head *head)
{
	WARN_ON(!head->rawlock && !head->spinlock);
	if (head->rawlock)
		WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));
	if (head->spinlock)
		WARN_ON_SMP(!spin_is_locked(head->spinlock));
	if (!plist_head_empty(head))
		plist_check_list(&plist_first(head)->prio_list);
	plist_check_list(&head->node_list);
}

#else
# define plist_check_head(h)	do { } while (0)
#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)
{
	struct plist_node *first, *iter, *prev = NULL;
	struct list_head *node_next = &head->node_list;

	plist_check_head(head);
	WARN_ON(!plist_node_empty(node));
	WARN_ON(!list_empty(&node->prio_list));

	if (plist_head_empty(head))
		goto ins_node;

	first = iter = plist_first(head);

	do {
		if (node->prio < iter->prio) {
			node_next = &iter->node_list;
			break;
		}

		prev = iter;
		iter = list_entry(iter->prio_list.next,
				struct plist_node, prio_list);
	} while (iter != first);

	if (!prev || prev->prio != node->prio)
		list_add_tail(&node->prio_list, &iter->prio_list);
ins_node:
	list_add_tail(&node->node_list, node_next);

	plist_check_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_check_head(head);

	if (!list_empty(&node->prio_list)) {
		if (node->node_list.next != &head->node_list) {
			struct plist_node *next;

			next = list_entry(node->node_list.next,
					struct plist_node, node_list);

			/* add the next plist_node into prio_list */
			if (list_empty(&next->prio_list))
				list_add(&next->prio_list, &node->prio_list);
		}
		list_del_init(&node->prio_list);
	}

	list_del_init(&node->node_list);

	plist_check_head(head);
}
Commit	Line	Data
77ba89c5 IM	1	/*
	2	* lib/plist.c
	3	*
	4	* Descending-priority-sorted double-linked list
	5	*
	6	* (C) 2002-2003 Intel Corp
	7	* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
	8	*
	9	* 2001-2005 (c) MontaVista Software, Inc.
	10	* Daniel Walker <dwalker@mvista.com>
	11	*
	12	* (C) 2005 Thomas Gleixner <tglx@linutronix.de>
	13	*
	14	* Simplifications of the original code by
	15	* Oleg Nesterov <oleg@tv-sign.ru>
	16	*
	17	* Licensed under the FSF's GNU Public License v2 or later.
	18	*
	19	* Based on simple lists (include/linux/list.h).
	20	*
	21	* This file contains the add / del functions which are considered to
	22	* be too large to inline. See include/linux/plist.h for further
	23	* information.
	24	*/
	25
	26	#include <linux/plist.h>
	27	#include <linux/spinlock.h>
	28
	29	#ifdef CONFIG_DEBUG_PI_LIST
	30
	31	static void plist_check_prev_next(struct list_head t, struct list_head p,
	32	struct list_head *n)
	33	{
5cd2b459 AV	34	WARN(n->prev != p \|\| p->next != n,
	35	"top: %p, n: %p, p: %p\n"
	36	"prev: %p, n: %p, p: %p\n"
	37	"next: %p, n: %p, p: %p\n",
	38	t, t->next, t->prev,
	39	p, p->next, p->prev,
	40	n, n->next, n->prev);
77ba89c5 IM	41	}
	42
	43	static void plist_check_list(struct list_head *top)
	44	{
	45	struct list_head prev = top, next = top->next;
	46
	47	plist_check_prev_next(top, prev, next);
	48	while (next != top) {
	49	prev = next;
	50	next = prev->next;
	51	plist_check_prev_next(top, prev, next);
	52	}
	53	}
	54
	55	static void plist_check_head(struct plist_head *head)
	56	{
a2672459 TG	57	WARN_ON(!head->rawlock && !head->spinlock);
	58	if (head->rawlock)
	59	WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));
	60	if (head->spinlock)
	61	WARN_ON_SMP(!spin_is_locked(head->spinlock));
bf6a9b83 LJ	62	if (!plist_head_empty(head))
bf6a9b83 LJ	63	plist_check_list(&plist_first(head)->prio_list);
77ba89c5 IM	64	plist_check_list(&head->node_list);
	65	}
	66
	67	#else
	68	# define plist_check_head(h) do { } while (0)
	69	#endif
	70
	71	/**
	72	* plist_add - add @node to @head
	73	*
	74	* @node: &struct plist_node pointer
	75	* @head: &struct plist_head pointer
	76	*/
	77	void plist_add(struct plist_node node, struct plist_head head)
	78	{
bf6a9b83 LJ	79	struct plist_node first, iter, *prev = NULL;
bf6a9b83 LJ	80	struct list_head *node_next = &head->node_list;
77ba89c5 IM	81
	82	plist_check_head(head);
	83	WARN_ON(!plist_node_empty(node));
bf6a9b83	84	WARN_ON(!list_empty(&node->prio_list));
77ba89c5	85
bf6a9b83 LJ	86	if (plist_head_empty(head))
	87	goto ins_node;
	88
	89	first = iter = plist_first(head);
	90
	91	do {
	92	if (node->prio < iter->prio) {
	93	node_next = &iter->node_list;
	94	break;
77ba89c5	95	}
77ba89c5	96
bf6a9b83 LJ	97	prev = iter;
	98	iter = list_entry(iter->prio_list.next,
	99	struct plist_node, prio_list);
	100	} while (iter != first);
	101
	102	if (!prev \|\| prev->prio != node->prio)
	103	list_add_tail(&node->prio_list, &iter->prio_list);
	104	ins_node:
	105	list_add_tail(&node->node_list, node_next);
77ba89c5 IM	106
	107	plist_check_head(head);
	108	}
	109
	110	/**
	111	* plist_del - Remove a @node from plist.
	112	*
	113	* @node: &struct plist_node pointer - entry to be removed
	114	* @head: &struct plist_head pointer - list head
	115	*/
	116	void plist_del(struct plist_node node, struct plist_head head)
	117	{
	118	plist_check_head(head);
	119
bf6a9b83 LJ	120	if (!list_empty(&node->prio_list)) {
	121	if (node->node_list.next != &head->node_list) {
	122	struct plist_node *next;
	123
	124	next = list_entry(node->node_list.next,
	125	struct plist_node, node_list);
77ba89c5	126
bf6a9b83 LJ	127	/* add the next plist_node into prio_list */
	128	if (list_empty(&next->prio_list))
	129	list_add(&next->prio_list, &node->prio_list);
	130	}
	131	list_del_init(&node->prio_list);
77ba89c5 IM	132	}
77ba89c5 IM	133
bf6a9b83	134	list_del_init(&node->node_list);
77ba89c5 IM	135
	136	plist_check_head(head);
	137	}