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authorPaul Mundt <lethal@linux-sh.org>2011-01-13 15:06:28 +0900
committerPaul Mundt <lethal@linux-sh.org>2011-01-13 15:06:28 +0900
commitf43dc23d5ea91fca257be02138a255f02d98e806 (patch)
treeb29722f6e965316e90ac97abf79923ced250dc21 /lib/timerqueue.c
parentf8e53553f452dcbf67cb89c8cba63a1cd6eb4cc0 (diff)
parent4162cf64973df51fc885825bc9ca4d055891c49f (diff)
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6 into common/serial-rework
Conflicts: arch/sh/kernel/cpu/sh2/setup-sh7619.c arch/sh/kernel/cpu/sh2a/setup-mxg.c arch/sh/kernel/cpu/sh2a/setup-sh7201.c arch/sh/kernel/cpu/sh2a/setup-sh7203.c arch/sh/kernel/cpu/sh2a/setup-sh7206.c arch/sh/kernel/cpu/sh3/setup-sh7705.c arch/sh/kernel/cpu/sh3/setup-sh770x.c arch/sh/kernel/cpu/sh3/setup-sh7710.c arch/sh/kernel/cpu/sh3/setup-sh7720.c arch/sh/kernel/cpu/sh4/setup-sh4-202.c arch/sh/kernel/cpu/sh4/setup-sh7750.c arch/sh/kernel/cpu/sh4/setup-sh7760.c arch/sh/kernel/cpu/sh4a/setup-sh7343.c arch/sh/kernel/cpu/sh4a/setup-sh7366.c arch/sh/kernel/cpu/sh4a/setup-sh7722.c arch/sh/kernel/cpu/sh4a/setup-sh7723.c arch/sh/kernel/cpu/sh4a/setup-sh7724.c arch/sh/kernel/cpu/sh4a/setup-sh7763.c arch/sh/kernel/cpu/sh4a/setup-sh7770.c arch/sh/kernel/cpu/sh4a/setup-sh7780.c arch/sh/kernel/cpu/sh4a/setup-sh7785.c arch/sh/kernel/cpu/sh4a/setup-sh7786.c arch/sh/kernel/cpu/sh4a/setup-shx3.c arch/sh/kernel/cpu/sh5/setup-sh5.c drivers/serial/sh-sci.c drivers/serial/sh-sci.h include/linux/serial_sci.h
Diffstat (limited to 'lib/timerqueue.c')
-rw-r--r--lib/timerqueue.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/lib/timerqueue.c b/lib/timerqueue.c
new file mode 100644
index 00000000000..e3a1050e682
--- /dev/null
+++ b/lib/timerqueue.c
@@ -0,0 +1,107 @@
+/*
+ * Generic Timer-queue
+ *
+ * Manages a simple queue of timers, ordered by expiration time.
+ * Uses rbtrees for quick list adds and expiration.
+ *
+ * NOTE: All of the following functions need to be serialized
+ * to avoid races. No locking is done by this libary code.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/timerqueue.h>
+#include <linux/rbtree.h>
+#include <linux/module.h>
+
+/**
+ * timerqueue_add - Adds timer to timerqueue.
+ *
+ * @head: head of timerqueue
+ * @node: timer node to be added
+ *
+ * Adds the timer node to the timerqueue, sorted by the
+ * node's expires value.
+ */
+void timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
+{
+ struct rb_node **p = &head->head.rb_node;
+ struct rb_node *parent = NULL;
+ struct timerqueue_node *ptr;
+
+ /* Make sure we don't add nodes that are already added */
+ WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
+
+ while (*p) {
+ parent = *p;
+ ptr = rb_entry(parent, struct timerqueue_node, node);
+ if (node->expires.tv64 < ptr->expires.tv64)
+ p = &(*p)->rb_left;
+ else
+ p = &(*p)->rb_right;
+ }
+ rb_link_node(&node->node, parent, p);
+ rb_insert_color(&node->node, &head->head);
+
+ if (!head->next || node->expires.tv64 < head->next->expires.tv64)
+ head->next = node;
+}
+EXPORT_SYMBOL_GPL(timerqueue_add);
+
+/**
+ * timerqueue_del - Removes a timer from the timerqueue.
+ *
+ * @head: head of timerqueue
+ * @node: timer node to be removed
+ *
+ * Removes the timer node from the timerqueue.
+ */
+void timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
+{
+ WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
+
+ /* update next pointer */
+ if (head->next == node) {
+ struct rb_node *rbn = rb_next(&node->node);
+
+ head->next = rbn ?
+ rb_entry(rbn, struct timerqueue_node, node) : NULL;
+ }
+ rb_erase(&node->node, &head->head);
+ RB_CLEAR_NODE(&node->node);
+}
+EXPORT_SYMBOL_GPL(timerqueue_del);
+
+/**
+ * timerqueue_iterate_next - Returns the timer after the provided timer
+ *
+ * @node: Pointer to a timer.
+ *
+ * Provides the timer that is after the given node. This is used, when
+ * necessary, to iterate through the list of timers in a timer list
+ * without modifying the list.
+ */
+struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
+{
+ struct rb_node *next;
+
+ if (!node)
+ return NULL;
+ next = rb_next(&node->node);
+ if (!next)
+ return NULL;
+ return container_of(next, struct timerqueue_node, node);
+}
+EXPORT_SYMBOL_GPL(timerqueue_iterate_next);