John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 1 | /* |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 2 | * Generic Timer-queue |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 3 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 4 | * Manages a simple queue of timers, ordered by expiration time. |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 libary 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 | |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 25 | #include <linux/timerqueue.h> |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 26 | #include <linux/rbtree.h> |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 27 | #include <linux/module.h> |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 28 | |
| 29 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 30 | * timerqueue_add - Adds timer to timerqueue. |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 31 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 32 | * @head: head of timerqueue |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 33 | * @node: timer node to be added |
| 34 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 35 | * Adds the timer node to the timerqueue, sorted by the |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 36 | * node's expires value. |
| 37 | */ |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 38 | void timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node) |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 39 | { |
| 40 | struct rb_node **p = &head->head.rb_node; |
| 41 | struct rb_node *parent = NULL; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 42 | struct timerqueue_node *ptr; |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 49 | ptr = rb_entry(parent, struct timerqueue_node, node); |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 61 | EXPORT_SYMBOL_GPL(timerqueue_add); |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 62 | |
| 63 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 64 | * timerqueue_del - Removes a timer from the timerqueue. |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 65 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 66 | * @head: head of timerqueue |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 67 | * @node: timer node to be removed |
| 68 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 69 | * Removes the timer node from the timerqueue. |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 70 | */ |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 71 | void timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 ? |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 80 | rb_entry(rbn, struct timerqueue_node, node) : NULL; |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 81 | } |
| 82 | rb_erase(&node->node, &head->head); |
| 83 | RB_CLEAR_NODE(&node->node); |
| 84 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 85 | EXPORT_SYMBOL_GPL(timerqueue_del); |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 86 | |
| 87 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 88 | * timerqueue_iterate_next - Returns the timer after the provided timer |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 | */ |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 96 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node) |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 105 | return container_of(next, struct timerqueue_node, node); |
John Stultz | 87de5ac | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 106 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 107 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next); |