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Commit | Line | Data |
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87de5ac7 | 1 | /* |
1f5a2479 | 2 | * Generic Timer-queue |
87de5ac7 | 3 | * |
1f5a2479 | 4 | * Manages a simple queue of timers, ordered by expiration time. |
87de5ac7 JS |
5 | * Uses rbtrees for quick list adds and expiration. |
6 | * | |
7 | * NOTE: All of the following functions need to be serialized | |
25985edc | 8 | * to avoid races. No locking is done by this library code. |
87de5ac7 JS |
9 | * |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software | |
22 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
23 | */ | |
24 | ||
1f5a2479 | 25 | #include <linux/timerqueue.h> |
87de5ac7 | 26 | #include <linux/rbtree.h> |
9bb99b14 | 27 | #include <linux/module.h> |
87de5ac7 JS |
28 | |
29 | /** | |
1f5a2479 | 30 | * timerqueue_add - Adds timer to timerqueue. |
87de5ac7 | 31 | * |
1f5a2479 | 32 | * @head: head of timerqueue |
87de5ac7 JS |
33 | * @node: timer node to be added |
34 | * | |
1f5a2479 | 35 | * Adds the timer node to the timerqueue, sorted by the |
87de5ac7 JS |
36 | * node's expires value. |
37 | */ | |
1f5a2479 | 38 | void timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node) |
87de5ac7 JS |
39 | { |
40 | struct rb_node **p = &head->head.rb_node; | |
41 | struct rb_node *parent = NULL; | |
1f5a2479 | 42 | struct timerqueue_node *ptr; |
87de5ac7 JS |
43 | |
44 | /* Make sure we don't add nodes that are already added */ | |
45 | WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node)); | |
46 | ||
47 | while (*p) { | |
48 | parent = *p; | |
1f5a2479 | 49 | ptr = rb_entry(parent, struct timerqueue_node, node); |
87de5ac7 JS |
50 | if (node->expires.tv64 < ptr->expires.tv64) |
51 | p = &(*p)->rb_left; | |
52 | else | |
53 | p = &(*p)->rb_right; | |
54 | } | |
55 | rb_link_node(&node->node, parent, p); | |
56 | rb_insert_color(&node->node, &head->head); | |
57 | ||
58 | if (!head->next || node->expires.tv64 < head->next->expires.tv64) | |
59 | head->next = node; | |
60 | } | |
9bb99b14 | 61 | EXPORT_SYMBOL_GPL(timerqueue_add); |
87de5ac7 JS |
62 | |
63 | /** | |
1f5a2479 | 64 | * timerqueue_del - Removes a timer from the timerqueue. |
87de5ac7 | 65 | * |
1f5a2479 | 66 | * @head: head of timerqueue |
87de5ac7 JS |
67 | * @node: timer node to be removed |
68 | * | |
1f5a2479 | 69 | * Removes the timer node from the timerqueue. |
87de5ac7 | 70 | */ |
1f5a2479 | 71 | void timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) |
87de5ac7 JS |
72 | { |
73 | WARN_ON_ONCE(RB_EMPTY_NODE(&node->node)); | |
74 | ||
75 | /* update next pointer */ | |
76 | if (head->next == node) { | |
77 | struct rb_node *rbn = rb_next(&node->node); | |
78 | ||
79 | head->next = rbn ? | |
1f5a2479 | 80 | rb_entry(rbn, struct timerqueue_node, node) : NULL; |
87de5ac7 JS |
81 | } |
82 | rb_erase(&node->node, &head->head); | |
83 | RB_CLEAR_NODE(&node->node); | |
84 | } | |
9bb99b14 | 85 | EXPORT_SYMBOL_GPL(timerqueue_del); |
87de5ac7 | 86 | |
87de5ac7 | 87 | /** |
1f5a2479 | 88 | * timerqueue_iterate_next - Returns the timer after the provided timer |
87de5ac7 JS |
89 | * |
90 | * @node: Pointer to a timer. | |
91 | * | |
92 | * Provides the timer that is after the given node. This is used, when | |
93 | * necessary, to iterate through the list of timers in a timer list | |
94 | * without modifying the list. | |
95 | */ | |
1f5a2479 | 96 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node) |
87de5ac7 JS |
97 | { |
98 | struct rb_node *next; | |
99 | ||
100 | if (!node) | |
101 | return NULL; | |
102 | next = rb_next(&node->node); | |
103 | if (!next) | |
104 | return NULL; | |
1f5a2479 | 105 | return container_of(next, struct timerqueue_node, node); |
87de5ac7 | 106 | } |
9bb99b14 | 107 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next); |