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      1 /*	$NetBSD: callback.h,v 1.3 2007/07/09 21:11:32 ad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c)2006 YAMAMOTO Takashi,
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #ifndef _SYS_CALLBACK_H_
     30 #define	_SYS_CALLBACK_H_
     31 
     32 #include <sys/queue.h>
     33 #include <sys/mutex.h>
     34 #include <sys/condvar.h>
     35 
     36 struct callback_entry {
     37 	TAILQ_ENTRY(callback_entry) ce_q;
     38 	int (*ce_func)(struct callback_entry *, void *, void *);
     39 	void *ce_obj;
     40 };
     41 
     42 struct callback_head {
     43 	kmutex_t ch_lock;
     44 	kcondvar_t ch_cv;
     45 	TAILQ_HEAD(, callback_entry) ch_q;
     46 	struct callback_entry *ch_next;
     47 	int ch_nentries;
     48 	int ch_running;
     49 	int ch_flags;
     50 };
     51 
     52 /* return values of ce_func */
     53 #define	CALLBACK_CHAIN_CONTINUE	0
     54 #define	CALLBACK_CHAIN_ABORT	1
     55 
     56 int callback_run_roundrobin(struct callback_head *, void *);
     57 void callback_register(struct callback_head *, struct callback_entry *,
     58     void *, int (*)(struct callback_entry *, void *, void *));
     59 void callback_unregister(struct callback_head *, struct callback_entry *);
     60 void callback_head_init(struct callback_head *, int);
     61 void callback_head_destroy(struct callback_head *);
     62 
     63 #endif /* !_SYS_CALLBACK_H_ */
     64