1 /* $NetBSD: subr_callback.c,v 1.7 2009/11/24 20:11:50 rmind 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 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: subr_callback.c,v 1.7 2009/11/24 20:11:50 rmind Exp $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/proc.h>
35 #include <sys/callback.h>
36
37 void
callback_head_init(struct callback_head * ch,int ipl)38 callback_head_init(struct callback_head *ch, int ipl)
39 {
40
41 memset(ch, 0, sizeof(struct callback_head));
42 mutex_init(&ch->ch_lock, MUTEX_DEFAULT, ipl);
43 cv_init(&ch->ch_cv, "callback");
44 TAILQ_INIT(&ch->ch_q);
45 #if 0 /* already zero-initialized */
46 ch->ch_next = NULL;
47 ch->ch_nentries = 0;
48 ch->ch_running = 0;
49 ch->ch_flags = 0;
50 #endif
51 }
52
53 void
callback_head_destroy(struct callback_head * ch)54 callback_head_destroy(struct callback_head *ch)
55 {
56
57 mutex_destroy(&ch->ch_lock);
58 cv_destroy(&ch->ch_cv);
59 }
60
61 void
callback_register(struct callback_head * ch,struct callback_entry * ce,void * obj,int (* fn)(struct callback_entry *,void *,void *))62 callback_register(struct callback_head *ch, struct callback_entry *ce,
63 void *obj, int (*fn)(struct callback_entry *, void *, void *))
64 {
65
66 KASSERT(fn != NULL);
67 ce->ce_func = fn;
68 ce->ce_obj = obj;
69 mutex_enter(&ch->ch_lock);
70 TAILQ_INSERT_TAIL(&ch->ch_q, ce, ce_q);
71 ch->ch_nentries++;
72 mutex_exit(&ch->ch_lock);
73 }
74
75 void
callback_unregister(struct callback_head * ch,struct callback_entry * ce)76 callback_unregister(struct callback_head *ch, struct callback_entry *ce)
77 {
78
79 mutex_enter(&ch->ch_lock);
80 while (ch->ch_running > 0)
81 cv_wait(&ch->ch_cv, &ch->ch_lock);
82 if (__predict_false(ch->ch_next == ce)) {
83 ch->ch_next = TAILQ_NEXT(ce, ce_q);
84 }
85 TAILQ_REMOVE(&ch->ch_q, ce, ce_q);
86 ch->ch_nentries--;
87 mutex_exit(&ch->ch_lock);
88 }
89
90 static int
callback_runone(struct callback_head * ch,void * arg)91 callback_runone(struct callback_head *ch, void *arg)
92 {
93 struct callback_entry *ce;
94 int result;
95
96 KASSERT(ch->ch_nentries > 0);
97 KASSERT(ch->ch_running > 0);
98
99 ce = ch->ch_next;
100 if (ce == NULL) {
101 ce = TAILQ_FIRST(&ch->ch_q);
102 }
103 KASSERT(ce != NULL);
104 KASSERT(ce->ce_func != NULL);
105 result = (*ce->ce_func)(ce, ce->ce_obj, arg);
106 ch->ch_next = TAILQ_NEXT(ce, ce_q);
107 return result;
108 }
109
110 static void
callback_run_enter(struct callback_head * ch)111 callback_run_enter(struct callback_head *ch)
112 {
113
114 mutex_enter(&ch->ch_lock);
115 ch->ch_running++;
116 mutex_exit(&ch->ch_lock);
117 }
118
119 static void
callback_run_leave(struct callback_head * ch)120 callback_run_leave(struct callback_head *ch)
121 {
122
123 mutex_enter(&ch->ch_lock);
124 KASSERT(ch->ch_running > 0);
125 ch->ch_running--;
126 if (ch->ch_running == 0)
127 cv_broadcast(&ch->ch_cv);
128 mutex_exit(&ch->ch_lock);
129 }
130
131 int
callback_run_roundrobin(struct callback_head * ch,void * arg)132 callback_run_roundrobin(struct callback_head *ch, void *arg)
133 {
134 int i;
135 int n;
136 int result = 0;
137
138 callback_run_enter(ch);
139 n = ch->ch_nentries;
140 for (i = 0; i < n; i++) {
141 result = callback_runone(ch, arg);
142 if (result != CALLBACK_CHAIN_CONTINUE) {
143 break;
144 }
145 }
146 callback_run_leave(ch);
147
148 return result;
149 }
150