1 /* $NetBSD: bufq_fcfs.c,v 1.13 2017/05/04 11:03:27 kamil 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 1.13 2017/05/04 11:03:27 kamil 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_private(bufq); 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_private(bufq); 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_private(bufq); 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
Indexes created Thu Sep 25 16:09:42 GMT 2025