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263 lines
5.9 KiB
263 lines
5.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* lib/plist.c |
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* |
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* Descending-priority-sorted double-linked list |
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* |
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* (C) 2002-2003 Intel Corp |
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* Inaky Perez-Gonzalez <[email protected]>. |
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* |
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* 2001-2005 (c) MontaVista Software, Inc. |
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* Daniel Walker <[email protected]> |
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* |
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* (C) 2005 Thomas Gleixner <[email protected]> |
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* |
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* Simplifications of the original code by |
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* Oleg Nesterov <[email protected]> |
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* |
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* Based on simple lists (include/linux/list.h). |
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* |
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* This file contains the add / del functions which are considered to |
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* be too large to inline. See include/linux/plist.h for further |
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* information. |
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*/ |
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#include <linux/bug.h> |
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#include <linux/plist.h> |
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#ifdef CONFIG_DEBUG_PLIST |
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static struct plist_head test_head; |
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static void plist_check_prev_next(struct list_head *t, struct list_head *p, |
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struct list_head *n) |
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{ |
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WARN(n->prev != p || p->next != n, |
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"top: %p, n: %p, p: %p\n" |
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"prev: %p, n: %p, p: %p\n" |
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"next: %p, n: %p, p: %p\n", |
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t, t->next, t->prev, |
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p, p->next, p->prev, |
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n, n->next, n->prev); |
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} |
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static void plist_check_list(struct list_head *top) |
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{ |
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struct list_head *prev = top, *next = top->next; |
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plist_check_prev_next(top, prev, next); |
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while (next != top) { |
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prev = next; |
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next = prev->next; |
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plist_check_prev_next(top, prev, next); |
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} |
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} |
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static void plist_check_head(struct plist_head *head) |
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{ |
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if (!plist_head_empty(head)) |
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plist_check_list(&plist_first(head)->prio_list); |
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plist_check_list(&head->node_list); |
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} |
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#else |
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# define plist_check_head(h) do { } while (0) |
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#endif |
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/** |
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* plist_add - add @node to @head |
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* |
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* @node: &struct plist_node pointer |
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* @head: &struct plist_head pointer |
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*/ |
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void plist_add(struct plist_node *node, struct plist_head *head) |
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{ |
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struct plist_node *first, *iter, *prev = NULL; |
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struct list_head *node_next = &head->node_list; |
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plist_check_head(head); |
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WARN_ON(!plist_node_empty(node)); |
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WARN_ON(!list_empty(&node->prio_list)); |
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if (plist_head_empty(head)) |
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goto ins_node; |
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first = iter = plist_first(head); |
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do { |
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if (node->prio < iter->prio) { |
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node_next = &iter->node_list; |
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break; |
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} |
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prev = iter; |
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iter = list_entry(iter->prio_list.next, |
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struct plist_node, prio_list); |
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} while (iter != first); |
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if (!prev || prev->prio != node->prio) |
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list_add_tail(&node->prio_list, &iter->prio_list); |
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ins_node: |
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list_add_tail(&node->node_list, node_next); |
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plist_check_head(head); |
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} |
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/** |
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* plist_del - Remove a @node from plist. |
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* |
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* @node: &struct plist_node pointer - entry to be removed |
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* @head: &struct plist_head pointer - list head |
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*/ |
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void plist_del(struct plist_node *node, struct plist_head *head) |
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{ |
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plist_check_head(head); |
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if (!list_empty(&node->prio_list)) { |
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if (node->node_list.next != &head->node_list) { |
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struct plist_node *next; |
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next = list_entry(node->node_list.next, |
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struct plist_node, node_list); |
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/* add the next plist_node into prio_list */ |
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if (list_empty(&next->prio_list)) |
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list_add(&next->prio_list, &node->prio_list); |
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} |
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list_del_init(&node->prio_list); |
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} |
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list_del_init(&node->node_list); |
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plist_check_head(head); |
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} |
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/** |
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* plist_requeue - Requeue @node at end of same-prio entries. |
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* |
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* This is essentially an optimized plist_del() followed by |
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* plist_add(). It moves an entry already in the plist to |
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* after any other same-priority entries. |
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* |
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* @node: &struct plist_node pointer - entry to be moved |
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* @head: &struct plist_head pointer - list head |
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*/ |
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void plist_requeue(struct plist_node *node, struct plist_head *head) |
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{ |
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struct plist_node *iter; |
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struct list_head *node_next = &head->node_list; |
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plist_check_head(head); |
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BUG_ON(plist_head_empty(head)); |
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BUG_ON(plist_node_empty(node)); |
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if (node == plist_last(head)) |
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return; |
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iter = plist_next(node); |
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if (node->prio != iter->prio) |
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return; |
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plist_del(node, head); |
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plist_for_each_continue(iter, head) { |
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if (node->prio != iter->prio) { |
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node_next = &iter->node_list; |
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break; |
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} |
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} |
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list_add_tail(&node->node_list, node_next); |
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plist_check_head(head); |
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} |
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#ifdef CONFIG_DEBUG_PLIST |
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#include <linux/sched.h> |
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#include <linux/sched/clock.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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static struct plist_node __initdata test_node[241]; |
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static void __init plist_test_check(int nr_expect) |
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{ |
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struct plist_node *first, *prio_pos, *node_pos; |
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if (plist_head_empty(&test_head)) { |
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BUG_ON(nr_expect != 0); |
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return; |
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} |
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prio_pos = first = plist_first(&test_head); |
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plist_for_each(node_pos, &test_head) { |
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if (nr_expect-- < 0) |
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break; |
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if (node_pos == first) |
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continue; |
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if (node_pos->prio == prio_pos->prio) { |
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BUG_ON(!list_empty(&node_pos->prio_list)); |
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continue; |
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} |
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BUG_ON(prio_pos->prio > node_pos->prio); |
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BUG_ON(prio_pos->prio_list.next != &node_pos->prio_list); |
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prio_pos = node_pos; |
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} |
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BUG_ON(nr_expect != 0); |
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BUG_ON(prio_pos->prio_list.next != &first->prio_list); |
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} |
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static void __init plist_test_requeue(struct plist_node *node) |
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{ |
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plist_requeue(node, &test_head); |
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if (node != plist_last(&test_head)) |
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BUG_ON(node->prio == plist_next(node)->prio); |
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} |
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static int __init plist_test(void) |
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{ |
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int nr_expect = 0, i, loop; |
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unsigned int r = local_clock(); |
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printk(KERN_DEBUG "start plist test\n"); |
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plist_head_init(&test_head); |
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for (i = 0; i < ARRAY_SIZE(test_node); i++) |
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plist_node_init(test_node + i, 0); |
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for (loop = 0; loop < 1000; loop++) { |
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r = r * 193939 % 47629; |
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i = r % ARRAY_SIZE(test_node); |
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if (plist_node_empty(test_node + i)) { |
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r = r * 193939 % 47629; |
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test_node[i].prio = r % 99; |
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plist_add(test_node + i, &test_head); |
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nr_expect++; |
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} else { |
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plist_del(test_node + i, &test_head); |
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nr_expect--; |
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} |
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plist_test_check(nr_expect); |
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if (!plist_node_empty(test_node + i)) { |
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plist_test_requeue(test_node + i); |
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plist_test_check(nr_expect); |
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} |
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} |
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for (i = 0; i < ARRAY_SIZE(test_node); i++) { |
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if (plist_node_empty(test_node + i)) |
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continue; |
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plist_del(test_node + i, &test_head); |
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nr_expect--; |
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plist_test_check(nr_expect); |
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} |
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printk(KERN_DEBUG "end plist test\n"); |
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return 0; |
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} |
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module_init(plist_test); |
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#endif
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