/* * 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); }