1 /* $NetBSD: bufq_fcfs.c,v 1.10 2009/01/19 14:54:28 yamt Exp $ */
2 /* NetBSD: subr_disk.c,v 1.61 2004/09/25 03:30:44 thorpej Exp */
3
4 /*-
5 * Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
10 * NASA Ames Research Center.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 /*
35 * Copyright (c) 1982, 1986, 1988, 1993
36 * The Regents of the University of California. All rights reserved.
37 * (c) UNIX System Laboratories, Inc.
38 * All or some portions of this file are derived from material licensed
39 * to the University of California by American Telephone and Telegraph
40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
41 * the permission of UNIX System Laboratories, Inc.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. Neither the name of the University nor the names of its contributors
52 * may be used to endorse or promote products derived from this software
53 * without specific prior written permission.
54 *
55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65 * SUCH DAMAGE.
66 *
67 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
68 */
69
70 #include <sys/cdefs.h>
71 __KERNEL_RCSID(0, "$NetBSD: bufq_fcfs.c,v 1.10 2009/01/19 14:54:28 yamt Exp $");
72
73 #include <sys/param.h>
74 #include <sys/systm.h>
75 #include <sys/buf.h>
76 #include <sys/bufq.h>
77 #include <sys/bufq_impl.h>
78 #include <sys/kmem.h>
79
80 /*
81 * First-come first-served sort for disks.
82 *
83 * Requests are appended to the queue without any reordering.
84 */
85
86 struct bufq_fcfs {
87 TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
88 };
89
90 static void bufq_fcfs_init(struct bufq_state *);
91 static void bufq_fcfs_put(struct bufq_state *, struct buf *);
92 static struct buf *bufq_fcfs_get(struct bufq_state *, int);
93
94 BUFQ_DEFINE(fcfs, 10, bufq_fcfs_init);
95
96 static void
bufq_fcfs_put(struct bufq_state * bufq,struct buf * bp)97 bufq_fcfs_put(struct bufq_state *bufq, struct buf *bp)
98 {
99 struct bufq_fcfs *fcfs = bufq->bq_private;
100
101 TAILQ_INSERT_TAIL(&fcfs->bq_head, bp, b_actq);
102 }
103
104 static struct buf *
bufq_fcfs_get(struct bufq_state * bufq,int remove)105 bufq_fcfs_get(struct bufq_state *bufq, int remove)
106 {
107 struct bufq_fcfs *fcfs = bufq->bq_private;
108 struct buf *bp;
109
110 bp = TAILQ_FIRST(&fcfs->bq_head);
111
112 if (bp != NULL && remove)
113 TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
114
115 return (bp);
116 }
117
118 static struct buf *
bufq_fcfs_cancel(struct bufq_state * bufq,struct buf * buf)119 bufq_fcfs_cancel(struct bufq_state *bufq, struct buf *buf)
120 {
121 struct bufq_fcfs *fcfs = bufq->bq_private;
122 struct buf *bp;
123
124 TAILQ_FOREACH(bp, &fcfs->bq_head, b_actq) {
125 if (bp == buf) {
126 TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
127 return buf;
128 }
129 }
130 return NULL;
131 }
132
133 static void
bufq_fcfs_fini(struct bufq_state * bufq)134 bufq_fcfs_fini(struct bufq_state *bufq)
135 {
136
137 KASSERT(bufq->bq_private != NULL);
138 kmem_free(bufq->bq_private, sizeof(struct bufq_fcfs));
139 }
140
141 static void
bufq_fcfs_init(struct bufq_state * bufq)142 bufq_fcfs_init(struct bufq_state *bufq)
143 {
144 struct bufq_fcfs *fcfs;
145
146 bufq->bq_get = bufq_fcfs_get;
147 bufq->bq_put = bufq_fcfs_put;
148 bufq->bq_cancel = bufq_fcfs_cancel;
149 bufq->bq_fini = bufq_fcfs_fini;
150 bufq->bq_private = kmem_zalloc(sizeof(struct bufq_fcfs), KM_SLEEP);
151 fcfs = (struct bufq_fcfs *)bufq->bq_private;
152 TAILQ_INIT(&fcfs->bq_head);
153 }
154