[patch 13/39] timerqueue: Let timerqueue_add/del return information

From: Thomas Gleixner
Date: Tue Apr 14 2015 - 17:09:05 EST


The hrtimer code is interested whether the added timer is the first
one to expire and whether the removed timer was the last one in the
tree. The add/del routines have that information already. So we can
return it right away instead of reevaluating it at the call site.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
---
include/linux/timerqueue.h | 8 ++++----
lib/timerqueue.c | 10 +++++++---
2 files changed, 11 insertions(+), 7 deletions(-)

Index: linux/include/linux/timerqueue.h
===================================================================
--- linux.orig/include/linux/timerqueue.h
+++ linux/include/linux/timerqueue.h
@@ -16,10 +16,10 @@ struct timerqueue_head {
};


-extern void timerqueue_add(struct timerqueue_head *head,
- struct timerqueue_node *node);
-extern void timerqueue_del(struct timerqueue_head *head,
- struct timerqueue_node *node);
+extern bool timerqueue_add(struct timerqueue_head *head,
+ struct timerqueue_node *node);
+extern bool timerqueue_del(struct timerqueue_head *head,
+ struct timerqueue_node *node);
extern struct timerqueue_node *timerqueue_iterate_next(
struct timerqueue_node *node);

Index: linux/lib/timerqueue.c
===================================================================
--- linux.orig/lib/timerqueue.c
+++ linux/lib/timerqueue.c
@@ -36,7 +36,7 @@
* 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)
+bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
{
struct rb_node **p = &head->head.rb_node;
struct rb_node *parent = NULL;
@@ -56,8 +56,11 @@ void timerqueue_add(struct timerqueue_he
rb_link_node(&node->node, parent, p);
rb_insert_color(&node->node, &head->head);

- if (!head->next || node->expires.tv64 < head->next->expires.tv64)
+ if (!head->next || node->expires.tv64 < head->next->expires.tv64) {
head->next = node;
+ return true;
+ }
+ return false;
}
EXPORT_SYMBOL_GPL(timerqueue_add);

@@ -69,7 +72,7 @@ EXPORT_SYMBOL_GPL(timerqueue_add);
*
* Removes the timer node from the timerqueue.
*/
-void timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
+bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
{
WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));

@@ -82,6 +85,7 @@ void timerqueue_del(struct timerqueue_he
}
rb_erase(&node->node, &head->head);
RB_CLEAR_NODE(&node->node);
+ return head->next != NULL;
}
EXPORT_SYMBOL_GPL(timerqueue_del);



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