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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 |
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 | |