/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_TIMERQUEUE_H
  #define _LINUX_TIMERQUEUE_H
  
  #include <linux/rbtree.h>
  #include <linux/ktime.h>
  
  
  struct timerqueue_node {
  	struct rb_node node;
  	ktime_t expires;
  };
  
  struct timerqueue_head {

  	struct rb_root_cached rb_root;

  };

  extern bool timerqueue_add(struct timerqueue_head *head,
  			   struct timerqueue_node *node);
  extern bool timerqueue_del(struct timerqueue_head *head,
  			   struct timerqueue_node *node);

  extern struct timerqueue_node *timerqueue_iterate_next(
  						struct timerqueue_node *node);

  /**

   * timerqueue_getnext - Returns the timer with the earliest expiration time

   *
   * @head: head of timerqueue
   *

   * Returns a pointer to the timer node that has the earliest expiration time.

   */
  static inline
  struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head)
  {

  	struct rb_node *leftmost = rb_first_cached(&head->rb_root);
  
  	return rb_entry(leftmost, struct timerqueue_node, node);

  }

  static inline void timerqueue_init(struct timerqueue_node *node)
  {

  	RB_CLEAR_NODE(&node->node);

  }

  static inline bool timerqueue_node_queued(struct timerqueue_node *node)
  {
  	return !RB_EMPTY_NODE(&node->node);
  }
  
  static inline bool timerqueue_node_expires(struct timerqueue_node *node)
  {
  	return node->expires;
  }

  static inline void timerqueue_init_head(struct timerqueue_head *head)
  {

  	head->rb_root = RB_ROOT_CACHED;

  }
  #endif /* _LINUX_TIMERQUEUE_H */