1 /* $NetBSD: pgfs_waitq.c,v 1.1 2011/10/12 01:05:00 yamt Exp $ */
2
3 /*-
4 * Copyright (c)2010,2011 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 /*
30 * a dumb wait queue on puffs_cc
31 */
32
33 #include <sys/cdefs.h>
34 #ifndef lint
35 __RCSID("$NetBSD: pgfs_waitq.c,v 1.1 2011/10/12 01:05:00 yamt Exp $");
36 #endif /* not lint */
37
38 #include <assert.h>
39 #include <puffs.h>
40
41 #include "pgfs_waitq.h"
42 #include "pgfs_debug.h"
43
44 struct waiter {
45 TAILQ_ENTRY(waiter) list;
46 struct puffs_cc *cc;
47 };
48
49 void
waitq_init(struct waitq * wq)50 waitq_init(struct waitq *wq)
51 {
52
53 TAILQ_INIT(wq);
54 }
55
56 void
waiton(struct waitq * wq,struct puffs_cc * cc)57 waiton(struct waitq *wq, struct puffs_cc *cc)
58 {
59 struct waiter w;
60
61 /*
62 * insert to the tail of the queue.
63 * some users rely on the FIFO behaviour.
64 */
65 w.cc = cc;
66 TAILQ_INSERT_TAIL(wq, &w, list);
67 puffs_cc_yield(cc);
68 }
69
70 struct puffs_cc *
wakeup_one(struct waitq * wq)71 wakeup_one(struct waitq *wq)
72 {
73
74 struct waiter *w;
75
76 w = TAILQ_FIRST(wq);
77 if (w != NULL) {
78 TAILQ_REMOVE(wq, w, list);
79 puffs_cc_schedule(w->cc);
80 DPRINTF("waking up %p\n", w->cc);
81 return w->cc;
82 }
83 return NULL;
84 }
85
86 #if 0
87 static void
88 wakeup(struct waitq *wq)
89 {
90
91 struct waiter *w;
92
93 TAILQ_FOREACH(w, wq, list) {
94 puffs_cc_schedule(w->cc);
95 DPRINTF("waking up %p\n", w->cc);
96 }
97 TAILQ_INIT(wq);
98 }
99 #endif
100