John Stultz | 87de5ac7 | 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 | 87de5ac7 | 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 | 87de5ac7 | 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 |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 8 | * to avoid races. No locking is done by this library code. |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 | |
Paul Gortmaker | 50af5ea | 2012-01-20 18:35:53 -0500 | [diff] [blame] | 25 | #include <linux/bug.h> |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 26 | #include <linux/timerqueue.h> |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 27 | #include <linux/rbtree.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 28 | #include <linux/export.h> |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 29 | |
| 30 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 31 | * timerqueue_add - Adds timer to timerqueue. |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 32 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 33 | * @head: head of timerqueue |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 34 | * @node: timer node to be added |
| 35 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 36 | * Adds the timer node to the timerqueue, sorted by the |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 37 | * node's expires value. |
| 38 | */ |
Thomas Gleixner | c320642 | 2015-04-14 21:08:46 +0000 | [diff] [blame] | 39 | bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node) |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 40 | { |
| 41 | struct rb_node **p = &head->head.rb_node; |
| 42 | struct rb_node *parent = NULL; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 43 | struct timerqueue_node *ptr; |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 44 | |
| 45 | /* Make sure we don't add nodes that are already added */ |
| 46 | WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node)); |
| 47 | |
| 48 | while (*p) { |
| 49 | parent = *p; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 50 | ptr = rb_entry(parent, struct timerqueue_node, node); |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 | |
Thomas Gleixner | c320642 | 2015-04-14 21:08:46 +0000 | [diff] [blame] | 59 | if (!head->next || node->expires.tv64 < head->next->expires.tv64) { |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 60 | head->next = node; |
Thomas Gleixner | c320642 | 2015-04-14 21:08:46 +0000 | [diff] [blame] | 61 | return true; |
| 62 | } |
| 63 | return false; |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 64 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 65 | EXPORT_SYMBOL_GPL(timerqueue_add); |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 66 | |
| 67 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 68 | * timerqueue_del - Removes a timer from the timerqueue. |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 69 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 70 | * @head: head of timerqueue |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 71 | * @node: timer node to be removed |
| 72 | * |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 73 | * Removes the timer node from the timerqueue. |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 74 | */ |
Thomas Gleixner | c320642 | 2015-04-14 21:08:46 +0000 | [diff] [blame] | 75 | bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 76 | { |
| 77 | WARN_ON_ONCE(RB_EMPTY_NODE(&node->node)); |
| 78 | |
| 79 | /* update next pointer */ |
| 80 | if (head->next == node) { |
| 81 | struct rb_node *rbn = rb_next(&node->node); |
| 82 | |
| 83 | head->next = rbn ? |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 84 | rb_entry(rbn, struct timerqueue_node, node) : NULL; |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 85 | } |
| 86 | rb_erase(&node->node, &head->head); |
| 87 | RB_CLEAR_NODE(&node->node); |
Thomas Gleixner | c320642 | 2015-04-14 21:08:46 +0000 | [diff] [blame] | 88 | return head->next != NULL; |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 89 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 90 | EXPORT_SYMBOL_GPL(timerqueue_del); |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 91 | |
| 92 | /** |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 93 | * timerqueue_iterate_next - Returns the timer after the provided timer |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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 | */ |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 101 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node) |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 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; |
John Stultz | 1f5a247 | 2010-12-09 12:02:18 -0800 | [diff] [blame] | 110 | return container_of(next, struct timerqueue_node, node); |
John Stultz | 87de5ac7 | 2010-09-20 17:42:46 -0700 | [diff] [blame] | 111 | } |
John Stultz | 9bb99b1 | 2010-12-06 13:32:12 -0800 | [diff] [blame] | 112 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next); |