1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
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 library 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/bug.h>
#include <linux/timerqueue.h>
#include <linux/rbtree.h>
#include <linux/export.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. Returns true if the newly added timer is the first expiring timer in
* the queue.
*/
bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
{
struct rb_node **p = &head->rb_root.rb_root.rb_node;
struct rb_node *parent = NULL;
struct timerqueue_node *ptr;
bool leftmost = true;
/* 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 < ptr->expires) {
p = &(*p)->rb_left;
} else {
p = &(*p)->rb_right;
leftmost = false;
}
}
rb_link_node(&node->node, parent, p);
rb_insert_color_cached(&node->node, &head->rb_root, leftmost);
return leftmost;
}
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. Returns true if the queue is
* not empty after the remove.
*/
bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
{
WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
rb_erase_cached(&node->node, &head->rb_root);
RB_CLEAR_NODE(&node->node);
return !RB_EMPTY_ROOT(&head->rb_root.rb_root);
}
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);
|
