--- /dev/null
+/*
+ * 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>
+
+#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);
+}
+
+/**
+ * plist_requeue - Requeue @node at end of same-prio entries.
+ *
+ * This is essentially an optimized plist_del() followed by
+ * plist_add(). It moves an entry already in the plist to
+ * after any other same-priority entries.
+ *
+ * @node: &struct plist_node pointer - entry to be moved
+ * @head: &struct plist_head pointer - list head
+ */
+void plist_requeue(struct plist_node *node, struct plist_head *head)
+{
+ struct plist_node *iter;
+ struct list_head *node_next = &head->node_list;
+
+ plist_check_head(head);
+ BUG_ON(plist_head_empty(head));
+ BUG_ON(plist_node_empty(node));
+
+ if (node == plist_last(head))
+ return;
+
+ iter = plist_next(node);
+
+ if (node->prio != iter->prio)
+ return;
+
+ plist_del(node, head);
+
+ plist_for_each_continue(iter, head) {
+ if (node->prio != iter->prio) {
+ node_next = &iter->node_list;
+ break;
+ }
+ }
+ list_add_tail(&node->node_list, node_next);
+
+ 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 void __init plist_test_requeue(struct plist_node *node)
+{
+ plist_requeue(node, &test_head);
+
+ if (node != plist_last(&test_head))
+ BUG_ON(node->prio == plist_next(node)->prio);
+}
+
+static int __init plist_test(void)
+{
+ int nr_expect = 0, i, loop;
+ unsigned int r = local_clock();
+
+ printk(KERN_DEBUG "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);
+ if (!plist_node_empty(test_node + i)) {
+ plist_test_requeue(test_node + i);
+ 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_DEBUG "end plist test\n");
+ return 0;
+}
+
+module_init(plist_test);
+
+#endif
Code Review / kvmfornfv.git / blobdiff