/* * 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){	if (n->prev != p || p->next != n) {		printk("top: %p, n: %p, p: %p\n", t, t->next, t->prev);		printk("prev: %p, n: %p, p: %p\n", p, p->next, p->prev);		printk("next: %p, n: %p, p: %p\n", n, n->next, n->prev);		WARN_ON(1);	}} 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->lock);	if (head->lock)		WARN_ON_SMP(!spin_is_locked(head->lock));	plist_check_list(&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 *iter; 	plist_check_head(head);	WARN_ON(!plist_node_empty(node)); 	list_for_each_entry(iter, &head->prio_list, plist.prio_list) {		if (node->prio < iter->prio)			goto lt_prio;		else if (node->prio == iter->prio) {			iter = list_entry(iter->plist.prio_list.next,					struct plist_node, plist.prio_list);			goto eq_prio;		}	} lt_prio:	list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);eq_prio:	list_add_tail(&node->plist.node_list, &iter->plist.node_list); 	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->plist.prio_list)) {		struct plist_node *next = plist_first(&node->plist); 		list_move_tail(&next->plist.prio_list, &node->plist.prio_list);		list_del_init(&node->plist.prio_list);	} 	list_del_init(&node->plist.node_list); 	plist_check_head(head);}