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      1 // SPDX-FileCopyrightText: 2010 Mathieu Desnoyers <mathieu.desnoyers (at) efficios.com>
      2 //
      3 // SPDX-License-Identifier: LGPL-2.1-or-later
      4 
      5 #ifndef _URCU_RCULFQUEUE_H
      6 #define _URCU_RCULFQUEUE_H
      7 
      8 /*
      9  * Userspace RCU library - Lock-Free RCU Queue
     10  */
     11 
     12 
     13 #ifdef __cplusplus
     14 extern "C" {
     15 #endif
     16 
     17 struct cds_lfq_queue_rcu;
     18 struct rcu_head;
     19 
     20 struct cds_lfq_node_rcu {
     21 	struct cds_lfq_node_rcu *next;
     22 	int dummy;
     23 };
     24 
     25 struct cds_lfq_queue_rcu {
     26 	struct cds_lfq_node_rcu *head, *tail;
     27 	void (*queue_call_rcu)(struct rcu_head *head,
     28 		void (*func)(struct rcu_head *head));
     29 };
     30 
     31 #ifdef _LGPL_SOURCE
     32 
     33 #include <urcu/static/rculfqueue.h>
     34 
     35 #define cds_lfq_node_init_rcu		_cds_lfq_node_init_rcu
     36 #define cds_lfq_init_rcu		_cds_lfq_init_rcu
     37 #define cds_lfq_destroy_rcu		_cds_lfq_destroy_rcu
     38 #define cds_lfq_enqueue_rcu		_cds_lfq_enqueue_rcu
     39 #define cds_lfq_dequeue_rcu		_cds_lfq_dequeue_rcu
     40 
     41 #else /* !_LGPL_SOURCE */
     42 
     43 extern void cds_lfq_node_init_rcu(struct cds_lfq_node_rcu *node);
     44 extern void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q,
     45 			     void queue_call_rcu(struct rcu_head *head,
     46 					void (*func)(struct rcu_head *head)));
     47 /*
     48  * The queue should be emptied before calling destroy.
     49  *
     50  * Return 0 on success, -EPERM if queue is not empty.
     51  */
     52 extern int cds_lfq_destroy_rcu(struct cds_lfq_queue_rcu *q);
     53 
     54 /*
     55  * Should be called under rcu read lock critical section.
     56  */
     57 extern void cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
     58 				struct cds_lfq_node_rcu *node);
     59 
     60 /*
     61  * Should be called under rcu read lock critical section.
     62  *
     63  * The caller must wait for a grace period to pass before freeing the returned
     64  * node or modifying the cds_lfq_node_rcu structure.
     65  * Returns NULL if queue is empty.
     66  */
     67 extern
     68 struct cds_lfq_node_rcu *cds_lfq_dequeue_rcu(struct cds_lfq_queue_rcu *q);
     69 
     70 #endif /* !_LGPL_SOURCE */
     71 
     72 #ifdef __cplusplus
     73 }
     74 #endif
     75 
     76 #endif /* _URCU_RCULFQUEUE_H */
     77