| 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 | |