1a59d1b8e0
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
101 lines
2.6 KiB
C
101 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Generic Timer-queue
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*
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* Manages a simple queue of timers, ordered by expiration time.
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* Uses rbtrees for quick list adds and expiration.
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*
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* NOTE: All of the following functions need to be serialized
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* to avoid races. No locking is done by this library code.
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*/
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#include <linux/bug.h>
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#include <linux/timerqueue.h>
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#include <linux/rbtree.h>
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#include <linux/export.h>
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/**
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* timerqueue_add - Adds timer to timerqueue.
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*
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* @head: head of timerqueue
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* @node: timer node to be added
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*
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* Adds the timer node to the timerqueue, sorted by the node's expires
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* value. Returns true if the newly added timer is the first expiring timer in
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* the queue.
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*/
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bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
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{
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struct rb_node **p = &head->head.rb_node;
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struct rb_node *parent = NULL;
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struct timerqueue_node *ptr;
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/* Make sure we don't add nodes that are already added */
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WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
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while (*p) {
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parent = *p;
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ptr = rb_entry(parent, struct timerqueue_node, node);
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if (node->expires < ptr->expires)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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rb_link_node(&node->node, parent, p);
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rb_insert_color(&node->node, &head->head);
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if (!head->next || node->expires < head->next->expires) {
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head->next = node;
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return true;
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}
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return false;
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}
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EXPORT_SYMBOL_GPL(timerqueue_add);
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/**
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* timerqueue_del - Removes a timer from the timerqueue.
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*
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* @head: head of timerqueue
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* @node: timer node to be removed
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*
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* Removes the timer node from the timerqueue. Returns true if the queue is
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* not empty after the remove.
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*/
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bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
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{
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WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
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/* update next pointer */
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if (head->next == node) {
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struct rb_node *rbn = rb_next(&node->node);
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head->next = rb_entry_safe(rbn, struct timerqueue_node, node);
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}
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rb_erase(&node->node, &head->head);
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RB_CLEAR_NODE(&node->node);
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return head->next != NULL;
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}
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EXPORT_SYMBOL_GPL(timerqueue_del);
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/**
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* timerqueue_iterate_next - Returns the timer after the provided timer
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*
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* @node: Pointer to a timer.
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*
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* Provides the timer that is after the given node. This is used, when
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* necessary, to iterate through the list of timers in a timer list
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* without modifying the list.
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*/
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struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
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{
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struct rb_node *next;
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if (!node)
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return NULL;
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next = rb_next(&node->node);
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if (!next)
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return NULL;
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return container_of(next, struct timerqueue_node, node);
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}
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EXPORT_SYMBOL_GPL(timerqueue_iterate_next);
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