From 77ba89c5cf28d5d98a3cae17f67a3e42b102cc25 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 27 Jun 2006 02:54:51 -0700 Subject: [PATCH] pi-futex: add plist implementation Add the priority-sorted list (plist) implementation. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/plist.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 118 insertions(+) create mode 100644 lib/plist.c (limited to 'lib/plist.c') diff --git a/lib/plist.c b/lib/plist.c new file mode 100644 index 000000000000..3074a02272f3 --- /dev/null +++ b/lib/plist.c @@ -0,0 +1,118 @@ +/* + * lib/plist.c + * + * Descending-priority-sorted double-linked list + * + * (C) 2002-2003 Intel Corp + * Inaky Perez-Gonzalez . + * + * 2001-2005 (c) MontaVista Software, Inc. + * Daniel Walker + * + * (C) 2005 Thomas Gleixner + * + * Simplifications of the original code by + * Oleg Nesterov + * + * 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 +#include + +#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); +} -- cgit v1.2.3