Root/lib/plist.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
1/*
2 * lib/plist.c
3 *
4 * Descending-priority-sorted double-linked list
5 *
6 * (C) 2002-2003 Intel Corp
7 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
8 *
9 * 2001-2005 (c) MontaVista Software, Inc.
10 * Daniel Walker <dwalker@mvista.com>
11 *
12 * (C) 2005 Thomas Gleixner <tglx@linutronix.de>
13 *
14 * Simplifications of the original code by
15 * Oleg Nesterov <oleg@tv-sign.ru>
16 *
17 * Licensed under the FSF's GNU Public License v2 or later.
18 *
19 * Based on simple lists (include/linux/list.h).
20 *
21 * This file contains the add / del functions which are considered to
22 * be too large to inline. See include/linux/plist.h for further
23 * information.
24 */
25
26#include <linux/plist.h>
27#include <linux/spinlock.h>
28
29#ifdef CONFIG_DEBUG_PI_LIST
30
31static struct plist_head test_head;
32
33static void plist_check_prev_next(struct list_head *t, struct list_head *p,
34                  struct list_head *n)
35{
36    WARN(n->prev != p || p->next != n,
37            "top: %p, n: %p, p: %p\n"
38            "prev: %p, n: %p, p: %p\n"
39            "next: %p, n: %p, p: %p\n",
40             t, t->next, t->prev,
41            p, p->next, p->prev,
42            n, n->next, n->prev);
43}
44
45static void plist_check_list(struct list_head *top)
46{
47    struct list_head *prev = top, *next = top->next;
48
49    plist_check_prev_next(top, prev, next);
50    while (next != top) {
51        prev = next;
52        next = prev->next;
53        plist_check_prev_next(top, prev, next);
54    }
55}
56
57static void plist_check_head(struct plist_head *head)
58{
59    if (!plist_head_empty(head))
60        plist_check_list(&plist_first(head)->prio_list);
61    plist_check_list(&head->node_list);
62}
63
64#else
65# define plist_check_head(h) do { } while (0)
66#endif
67
68/**
69 * plist_add - add @node to @head
70 *
71 * @node: &struct plist_node pointer
72 * @head: &struct plist_head pointer
73 */
74void plist_add(struct plist_node *node, struct plist_head *head)
75{
76    struct plist_node *first, *iter, *prev = NULL;
77    struct list_head *node_next = &head->node_list;
78
79    plist_check_head(head);
80    WARN_ON(!plist_node_empty(node));
81    WARN_ON(!list_empty(&node->prio_list));
82
83    if (plist_head_empty(head))
84        goto ins_node;
85
86    first = iter = plist_first(head);
87
88    do {
89        if (node->prio < iter->prio) {
90            node_next = &iter->node_list;
91            break;
92        }
93
94        prev = iter;
95        iter = list_entry(iter->prio_list.next,
96                struct plist_node, prio_list);
97    } while (iter != first);
98
99    if (!prev || prev->prio != node->prio)
100        list_add_tail(&node->prio_list, &iter->prio_list);
101ins_node:
102    list_add_tail(&node->node_list, node_next);
103
104    plist_check_head(head);
105}
106
107/**
108 * plist_del - Remove a @node from plist.
109 *
110 * @node: &struct plist_node pointer - entry to be removed
111 * @head: &struct plist_head pointer - list head
112 */
113void plist_del(struct plist_node *node, struct plist_head *head)
114{
115    plist_check_head(head);
116
117    if (!list_empty(&node->prio_list)) {
118        if (node->node_list.next != &head->node_list) {
119            struct plist_node *next;
120
121            next = list_entry(node->node_list.next,
122                    struct plist_node, node_list);
123
124            /* add the next plist_node into prio_list */
125            if (list_empty(&next->prio_list))
126                list_add(&next->prio_list, &node->prio_list);
127        }
128        list_del_init(&node->prio_list);
129    }
130
131    list_del_init(&node->node_list);
132
133    plist_check_head(head);
134}
135
136#ifdef CONFIG_DEBUG_PI_LIST
137#include <linux/sched.h>
138#include <linux/module.h>
139#include <linux/init.h>
140
141static struct plist_node __initdata test_node[241];
142
143static void __init plist_test_check(int nr_expect)
144{
145    struct plist_node *first, *prio_pos, *node_pos;
146
147    if (plist_head_empty(&test_head)) {
148        BUG_ON(nr_expect != 0);
149        return;
150    }
151
152    prio_pos = first = plist_first(&test_head);
153    plist_for_each(node_pos, &test_head) {
154        if (nr_expect-- < 0)
155            break;
156        if (node_pos == first)
157            continue;
158        if (node_pos->prio == prio_pos->prio) {
159            BUG_ON(!list_empty(&node_pos->prio_list));
160            continue;
161        }
162
163        BUG_ON(prio_pos->prio > node_pos->prio);
164        BUG_ON(prio_pos->prio_list.next != &node_pos->prio_list);
165        prio_pos = node_pos;
166    }
167
168    BUG_ON(nr_expect != 0);
169    BUG_ON(prio_pos->prio_list.next != &first->prio_list);
170}
171
172static int __init plist_test(void)
173{
174    int nr_expect = 0, i, loop;
175    unsigned int r = local_clock();
176
177    printk(KERN_INFO "start plist test\n");
178    plist_head_init(&test_head);
179    for (i = 0; i < ARRAY_SIZE(test_node); i++)
180        plist_node_init(test_node + i, 0);
181
182    for (loop = 0; loop < 1000; loop++) {
183        r = r * 193939 % 47629;
184        i = r % ARRAY_SIZE(test_node);
185        if (plist_node_empty(test_node + i)) {
186            r = r * 193939 % 47629;
187            test_node[i].prio = r % 99;
188            plist_add(test_node + i, &test_head);
189            nr_expect++;
190        } else {
191            plist_del(test_node + i, &test_head);
192            nr_expect--;
193        }
194        plist_test_check(nr_expect);
195    }
196
197    for (i = 0; i < ARRAY_SIZE(test_node); i++) {
198        if (plist_node_empty(test_node + i))
199            continue;
200        plist_del(test_node + i, &test_head);
201        nr_expect--;
202        plist_test_check(nr_expect);
203    }
204
205    printk(KERN_INFO "end plist test\n");
206    return 0;
207}
208
209module_init(plist_test);
210
211#endif
212

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