This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / lib / plist.c

diff --git a/lib/plist.c b/lib/plist.c
new file mode 100644 (file)
index 0000000..3074a02
--- /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 <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/plist.h>
+#include <linux/spinlock.h>
+
+#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);
+}