1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 *  Generic Timer-queue
 4 *
 5 *  Manages a simple queue of timers, ordered by expiration time.
 6 *  Uses rbtrees for quick list adds and expiration.
 7 *
 8 *  NOTE: All of the following functions need to be serialized
 9 *  to avoid races. No locking is done by this library code.
10 */
11
12#include <linux/bug.h>
13#include <linux/timerqueue.h>
14#include <linux/rbtree.h>
15#include <linux/export.h>
16
 
 
 
 
 
 
 
 
17/**
18 * timerqueue_add - Adds timer to timerqueue.
19 *
20 * @head: head of timerqueue
21 * @node: timer node to be added
22 *
23 * Adds the timer node to the timerqueue, sorted by the node's expires
24 * value. Returns true if the newly added timer is the first expiring timer in
25 * the queue.
26 */
27bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
28{
29	struct rb_node **p = &head->rb_root.rb_root.rb_node;
30	struct rb_node *parent = NULL;
31	struct timerqueue_node *ptr;
32	bool leftmost = true;
33
34	/* Make sure we don't add nodes that are already added */
35	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
36
37	while (*p) {
38		parent = *p;
39		ptr = rb_entry(parent, struct timerqueue_node, node);
40		if (node->expires < ptr->expires) {
41			p = &(*p)->rb_left;
42		} else {
43			p = &(*p)->rb_right;
44			leftmost = false;
45		}
46	}
47	rb_link_node(&node->node, parent, p);
48	rb_insert_color_cached(&node->node, &head->rb_root, leftmost);
49
50	return leftmost;
51}
52EXPORT_SYMBOL_GPL(timerqueue_add);
53
54/**
55 * timerqueue_del - Removes a timer from the timerqueue.
56 *
57 * @head: head of timerqueue
58 * @node: timer node to be removed
59 *
60 * Removes the timer node from the timerqueue. Returns true if the queue is
61 * not empty after the remove.
62 */
63bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
64{
65	WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
66
67	rb_erase_cached(&node->node, &head->rb_root);
68	RB_CLEAR_NODE(&node->node);
69
70	return !RB_EMPTY_ROOT(&head->rb_root.rb_root);
71}
72EXPORT_SYMBOL_GPL(timerqueue_del);
73
74/**
75 * timerqueue_iterate_next - Returns the timer after the provided timer
76 *
77 * @node: Pointer to a timer.
78 *
79 * Provides the timer that is after the given node. This is used, when
80 * necessary, to iterate through the list of timers in a timer list
81 * without modifying the list.
82 */
83struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
84{
85	struct rb_node *next;
86
87	if (!node)
88		return NULL;
89	next = rb_next(&node->node);
90	if (!next)
91		return NULL;
92	return container_of(next, struct timerqueue_node, node);
93}
94EXPORT_SYMBOL_GPL(timerqueue_iterate_next);

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 *  Generic Timer-queue
 4 *
 5 *  Manages a simple queue of timers, ordered by expiration time.
 6 *  Uses rbtrees for quick list adds and expiration.
 7 *
 8 *  NOTE: All of the following functions need to be serialized
 9 *  to avoid races. No locking is done by this library code.
10 */
11
12#include <linux/bug.h>
13#include <linux/timerqueue.h>
14#include <linux/rbtree.h>
15#include <linux/export.h>
16
17#define __node_2_tq(_n) \
18	rb_entry((_n), struct timerqueue_node, node)
19
20static inline bool __timerqueue_less(struct rb_node *a, const struct rb_node *b)
21{
22	return __node_2_tq(a)->expires < __node_2_tq(b)->expires;
23}
24
25/**
26 * timerqueue_add - Adds timer to timerqueue.
27 *
28 * @head: head of timerqueue
29 * @node: timer node to be added
30 *
31 * Adds the timer node to the timerqueue, sorted by the node's expires
32 * value. Returns true if the newly added timer is the first expiring timer in
33 * the queue.
34 */
35bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
36{
 
 
 
 
 
37	/* Make sure we don't add nodes that are already added */
38	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
39
40	return rb_add_cached(&node->node, &head->rb_root, __timerqueue_less);
 
 
 
 
 
 
 
 
 
 
 
 
 
41}
42EXPORT_SYMBOL_GPL(timerqueue_add);
43
44/**
45 * timerqueue_del - Removes a timer from the timerqueue.
46 *
47 * @head: head of timerqueue
48 * @node: timer node to be removed
49 *
50 * Removes the timer node from the timerqueue. Returns true if the queue is
51 * not empty after the remove.
52 */
53bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
54{
55	WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
56
57	rb_erase_cached(&node->node, &head->rb_root);
58	RB_CLEAR_NODE(&node->node);
59
60	return !RB_EMPTY_ROOT(&head->rb_root.rb_root);
61}
62EXPORT_SYMBOL_GPL(timerqueue_del);
63
64/**
65 * timerqueue_iterate_next - Returns the timer after the provided timer
66 *
67 * @node: Pointer to a timer.
68 *
69 * Provides the timer that is after the given node. This is used, when
70 * necessary, to iterate through the list of timers in a timer list
71 * without modifying the list.
72 */
73struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
74{
75	struct rb_node *next;
76
77	if (!node)
78		return NULL;
79	next = rb_next(&node->node);
80	if (!next)
81		return NULL;
82	return container_of(next, struct timerqueue_node, node);
83}
84EXPORT_SYMBOL_GPL(timerqueue_iterate_next);