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authorIngo Molnar <mingo@elte.hu>2006-06-27 02:54:51 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-27 17:32:46 -0700
commit77ba89c5cf28d5d98a3cae17f67a3e42b102cc25 (patch)
treed487b536522574ab183cc600b62008c60db85b59 /lib/plist.c
parent8eb94f80dd2da5977c35cd094f0802c1501a12cd (diff)
downloadlinux-linaro-stable-77ba89c5cf28d5d98a3cae17f67a3e42b102cc25.tar.gz
[PATCH] pi-futex: add plist implementation
Add the priority-sorted list (plist) implementation. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'lib/plist.c')
-rw-r--r--lib/plist.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/lib/plist.c b/lib/plist.c
new file mode 100644
index 000000000000..3074a02272f3
--- /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);
+}