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