1 | /* $NetBSD: bufq_fcfs.c,v 1.12 2016/11/16 10:42:14 pgoyette 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 1.12 2016/11/16 10:42:14 pgoyette 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 | #include <sys/module.h> |
80 | |
81 | /* |
82 | * First-come first-served sort for disks. |
83 | * |
84 | * Requests are appended to the queue without any reordering. |
85 | */ |
86 | |
87 | struct bufq_fcfs { |
88 | TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */ |
89 | }; |
90 | |
91 | static void bufq_fcfs_init(struct bufq_state *); |
92 | static void bufq_fcfs_put(struct bufq_state *, struct buf *); |
93 | static struct buf *bufq_fcfs_get(struct bufq_state *, int); |
94 | |
95 | BUFQ_DEFINE(fcfs, 10, bufq_fcfs_init); |
96 | |
97 | static void |
98 | bufq_fcfs_put(struct bufq_state *bufq, struct buf *bp) |
99 | { |
100 | struct bufq_fcfs *fcfs = bufq->bq_private; |
101 | |
102 | TAILQ_INSERT_TAIL(&fcfs->bq_head, bp, b_actq); |
103 | } |
104 | |
105 | static struct buf * |
106 | bufq_fcfs_get(struct bufq_state *bufq, int remove) |
107 | { |
108 | struct bufq_fcfs *fcfs = bufq->bq_private; |
109 | struct buf *bp; |
110 | |
111 | bp = TAILQ_FIRST(&fcfs->bq_head); |
112 | |
113 | if (bp != NULL && remove) |
114 | TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq); |
115 | |
116 | return (bp); |
117 | } |
118 | |
119 | static struct buf * |
120 | bufq_fcfs_cancel(struct bufq_state *bufq, struct buf *buf) |
121 | { |
122 | struct bufq_fcfs *fcfs = bufq->bq_private; |
123 | struct buf *bp; |
124 | |
125 | TAILQ_FOREACH(bp, &fcfs->bq_head, b_actq) { |
126 | if (bp == buf) { |
127 | TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq); |
128 | return buf; |
129 | } |
130 | } |
131 | return NULL; |
132 | } |
133 | |
134 | static void |
135 | bufq_fcfs_fini(struct bufq_state *bufq) |
136 | { |
137 | |
138 | KASSERT(bufq->bq_private != NULL); |
139 | kmem_free(bufq->bq_private, sizeof(struct bufq_fcfs)); |
140 | } |
141 | |
142 | static void |
143 | bufq_fcfs_init(struct bufq_state *bufq) |
144 | { |
145 | struct bufq_fcfs *fcfs; |
146 | |
147 | bufq->bq_get = bufq_fcfs_get; |
148 | bufq->bq_put = bufq_fcfs_put; |
149 | bufq->bq_cancel = bufq_fcfs_cancel; |
150 | bufq->bq_fini = bufq_fcfs_fini; |
151 | bufq->bq_private = kmem_zalloc(sizeof(struct bufq_fcfs), KM_SLEEP); |
152 | fcfs = (struct bufq_fcfs *)bufq->bq_private; |
153 | TAILQ_INIT(&fcfs->bq_head); |
154 | } |
155 | |
156 | MODULE(MODULE_CLASS_BUFQ, bufq_fcfs, NULL); |
157 | |
158 | static int |
159 | bufq_fcfs_modcmd(modcmd_t cmd, void *opaque) |
160 | { |
161 | |
162 | switch (cmd) { |
163 | case MODULE_CMD_INIT: |
164 | return bufq_register(&bufq_strat_fcfs); |
165 | case MODULE_CMD_FINI: |
166 | return bufq_unregister(&bufq_strat_fcfs); |
167 | default: |
168 | return ENOTTY; |
169 | } |
170 | } |
171 | |