diff options
Diffstat (limited to 'lib/plist.c')
| -rw-r--r-- | lib/plist.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/lib/plist.c b/lib/plist.c new file mode 100644 index 00000000..6ab0e521 --- /dev/null +++ b/lib/plist.c @@ -0,0 +1,212 @@ +/* + * 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/bug.h> +#include <linux/plist.h> +#include <linux/spinlock.h> + +#ifdef CONFIG_DEBUG_PI_LIST + +static struct plist_head test_head; + +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) +{ + 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); +} + +#ifdef CONFIG_DEBUG_PI_LIST +#include <linux/sched.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) +{ + struct plist_node *first, *prio_pos, *node_pos; + + if (plist_head_empty(&test_head)) { + BUG_ON(nr_expect != 0); + return; + } + + prio_pos = first = plist_first(&test_head); + plist_for_each(node_pos, &test_head) { + if (nr_expect-- < 0) + break; + if (node_pos == first) + continue; + if (node_pos->prio == prio_pos->prio) { + BUG_ON(!list_empty(&node_pos->prio_list)); + continue; + } + + BUG_ON(prio_pos->prio > node_pos->prio); + BUG_ON(prio_pos->prio_list.next != &node_pos->prio_list); + prio_pos = node_pos; + } + + BUG_ON(nr_expect != 0); + BUG_ON(prio_pos->prio_list.next != &first->prio_list); +} + +static int __init plist_test(void) +{ + int nr_expect = 0, i, loop; + unsigned int r = local_clock(); + + printk(KERN_INFO "start plist test\n"); + plist_head_init(&test_head); + for (i = 0; i < ARRAY_SIZE(test_node); i++) + plist_node_init(test_node + i, 0); + + for (loop = 0; loop < 1000; loop++) { + r = r * 193939 % 47629; + i = r % ARRAY_SIZE(test_node); + if (plist_node_empty(test_node + i)) { + r = r * 193939 % 47629; + test_node[i].prio = r % 99; + plist_add(test_node + i, &test_head); + nr_expect++; + } else { + plist_del(test_node + i, &test_head); + nr_expect--; + } + plist_test_check(nr_expect); + } + + for (i = 0; i < ARRAY_SIZE(test_node); i++) { + if (plist_node_empty(test_node + i)) + continue; + plist_del(test_node + i, &test_head); + nr_expect--; + plist_test_check(nr_expect); + } + + printk(KERN_INFO "end plist test\n"); + return 0; +} + +module_init(plist_test); + +#endif |