| 1 | |
| 2 | * Generic Timer-queue
|
| 3 | *
|
| 4 | * Manages a simple queue of timers, ordered by expiration time.
|
| 5 | * Uses rbtrees for quick list adds and expiration.
|
| 6 | *
|
| 7 | * NOTE: All of the following functions need to be serialized
|
| 8 | * to avoid races. No locking is done by this library code.
|
| 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 |
|
| 25 | #include <linux/bug.h>
|
| 26 | #include <linux/timerqueue.h>
|
| 27 | #include <linux/rbtree.h>
|
| 28 | #include <linux/export.h>
|
| 29 |
|
| 30 | |
| 31 | * timerqueue_add - Adds timer to timerqueue.
|
| 32 | *
|
| 33 | * @head: head of timerqueue
|
| 34 | * @node: timer node to be added
|
| 35 | *
|
| 36 | * Adds the timer node to the timerqueue, sorted by the
|
| 37 | * node's expires value.
|
| 38 |
|
| 39 | bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
|
| 40 | {
|
| 41 | struct rb_node **p = &head->head.rb_node;
|
| 42 | struct rb_node *parent = NULL;
|
| 43 | struct timerqueue_node *ptr;
|
| 44 |
|
| 45 |
|
| 46 | WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
|
| 47 |
|
| 48 | while (*p) {
|
| 49 | parent = *p;
|
| 50 | ptr = rb_entry(parent, struct timerqueue_node, node);
|
| 51 | if (node->expires.tv64 < ptr->expires.tv64)
|
| 52 | p = &(*p)->rb_left;
|
| 53 | else
|
| 54 | p = &(*p)->rb_right;
|
| 55 | }
|
| 56 | rb_link_node(&node->node, parent, p);
|
| 57 | rb_insert_color(&node->node, &head->head);
|
| 58 |
|
| 59 | if (!head->next || node->expires.tv64 < head->next->expires.tv64) {
|
| 60 | head->next = node;
|
| 61 | return true;
|
| 62 | }
|
| 63 | return false;
|
| 64 | }
|
| 65 | EXPORT_SYMBOL_GPL(timerqueue_add);
|
| 66 |
|
| 67 | |
| 68 | * timerqueue_del - Removes a timer from the timerqueue.
|
| 69 | *
|
| 70 | * @head: head of timerqueue
|
| 71 | * @node: timer node to be removed
|
| 72 | *
|
| 73 | * Removes the timer node from the timerqueue.
|
| 74 |
|
| 75 | bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
|
| 76 | {
|
| 77 | WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
|
| 78 |
|
| 79 |
|
| 80 | if (head->next == node) {
|
| 81 | struct rb_node *rbn = rb_next(&node->node);
|
| 82 |
|
| 83 | head->next = rbn ?
|
| 84 | rb_entry(rbn, struct timerqueue_node, node) : NULL;
|
| 85 | }
|
| 86 | rb_erase(&node->node, &head->head);
|
| 87 | RB_CLEAR_NODE(&node->node);
|
| 88 | return head->next != NULL;
|
| 89 | }
|
| 90 | EXPORT_SYMBOL_GPL(timerqueue_del);
|
| 91 |
|
| 92 | |
| 93 | * timerqueue_iterate_next - Returns the timer after the provided timer
|
| 94 | *
|
| 95 | * @node: Pointer to a timer.
|
| 96 | *
|
| 97 | * Provides the timer that is after the given node. This is used, when
|
| 98 | * necessary, to iterate through the list of timers in a timer list
|
| 99 | * without modifying the list.
|
| 100 |
|
| 101 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
|
| 102 | {
|
| 103 | struct rb_node *next;
|
| 104 |
|
| 105 | if (!node)
|
| 106 | return NULL;
|
| 107 | next = rb_next(&node->node);
|
| 108 | if (!next)
|
| 109 | return NULL;
|
| 110 | return container_of(next, struct timerqueue_node, node);
|
| 111 | }
|
| 112 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next);
|