// SPDX-License-Identifier: GPL-2.0-or-later/* *  Generic Timer-queue * *  Manages a simple queue of timers, ordered by expiration time. *  Uses rbtrees for quick list adds and expiration. * *  NOTE: All of the following functions need to be serialized *  to avoid races. No locking is done by this library code. */ #include <linux/bug.h>#include <linux/timerqueue.h>#include <linux/rbtree.h>#include <linux/export.h> #define __node_2_tq(_n) \	rb_entry((_n), struct timerqueue_node, node) static inline bool __timerqueue_less(struct rb_node *a, const struct rb_node *b){	return __node_2_tq(a)->expires < __node_2_tq(b)->expires;} /** * timerqueue_add - Adds timer to timerqueue. * * @head: head of timerqueue * @node: timer node to be added * * Adds the timer node to the timerqueue, sorted by the node's expires * value. Returns true if the newly added timer is the first expiring timer in * the queue. */bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node){	/* Make sure we don't add nodes that are already added */	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node)); 	return rb_add_cached(&node->node, &head->rb_root, __timerqueue_less);}EXPORT_SYMBOL_GPL(timerqueue_add); /** * timerqueue_del - Removes a timer from the timerqueue. * * @head: head of timerqueue * @node: timer node to be removed * * Removes the timer node from the timerqueue. Returns true if the queue is * not empty after the remove. */bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node){	WARN_ON_ONCE(RB_EMPTY_NODE(&node->node)); 	rb_erase_cached(&node->node, &head->rb_root);	RB_CLEAR_NODE(&node->node); 	return !RB_EMPTY_ROOT(&head->rb_root.rb_root);}EXPORT_SYMBOL_GPL(timerqueue_del); /** * timerqueue_iterate_next - Returns the timer after the provided timer * * @node: Pointer to a timer. * * Provides the timer that is after the given node. This is used, when * necessary, to iterate through the list of timers in a timer list * without modifying the list. */struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node){	struct rb_node *next; 	if (!node)		return NULL;	next = rb_next(&node->node);	if (!next)		return NULL;	return container_of(next, struct timerqueue_node, node);}EXPORT_SYMBOL_GPL(timerqueue_iterate_next); #define __node_2_tq_linked(_n) \	container_of(rb_entry((_n), struct rb_node_linked, node), struct timerqueue_linked_node, node) static __always_inline bool __tq_linked_less(struct rb_node *a, const struct rb_node *b){	return __node_2_tq_linked(a)->expires < __node_2_tq_linked(b)->expires;} bool timerqueue_linked_add(struct timerqueue_linked_head *head, struct timerqueue_linked_node *node){	return rb_add_linked(&node->node, &head->rb_root, __tq_linked_less);}EXPORT_SYMBOL_GPL(timerqueue_linked_add);