154 lines
5.4 KiB
C
154 lines
5.4 KiB
C
/* $NetBSD: bufq_fcfs.c,v 1.10 2009/01/19 14:54:28 yamt Exp $ */
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/* NetBSD: subr_disk.c,v 1.61 2004/09/25 03:30:44 thorpej Exp */
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/*-
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* Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: bufq_fcfs.c,v 1.10 2009/01/19 14:54:28 yamt Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/bufq.h>
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#include <sys/bufq_impl.h>
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#include <sys/kmem.h>
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/*
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* First-come first-served sort for disks.
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*
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* Requests are appended to the queue without any reordering.
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*/
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struct bufq_fcfs {
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TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
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};
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static void bufq_fcfs_init(struct bufq_state *);
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static void bufq_fcfs_put(struct bufq_state *, struct buf *);
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static struct buf *bufq_fcfs_get(struct bufq_state *, int);
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BUFQ_DEFINE(fcfs, 10, bufq_fcfs_init);
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static void
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bufq_fcfs_put(struct bufq_state *bufq, struct buf *bp)
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{
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struct bufq_fcfs *fcfs = bufq->bq_private;
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TAILQ_INSERT_TAIL(&fcfs->bq_head, bp, b_actq);
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}
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static struct buf *
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bufq_fcfs_get(struct bufq_state *bufq, int remove)
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{
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struct bufq_fcfs *fcfs = bufq->bq_private;
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struct buf *bp;
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bp = TAILQ_FIRST(&fcfs->bq_head);
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if (bp != NULL && remove)
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TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
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return (bp);
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}
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static struct buf *
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bufq_fcfs_cancel(struct bufq_state *bufq, struct buf *buf)
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{
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struct bufq_fcfs *fcfs = bufq->bq_private;
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struct buf *bp;
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TAILQ_FOREACH(bp, &fcfs->bq_head, b_actq) {
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if (bp == buf) {
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TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
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return buf;
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}
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}
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return NULL;
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}
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static void
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bufq_fcfs_fini(struct bufq_state *bufq)
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{
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KASSERT(bufq->bq_private != NULL);
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kmem_free(bufq->bq_private, sizeof(struct bufq_fcfs));
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}
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static void
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bufq_fcfs_init(struct bufq_state *bufq)
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{
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struct bufq_fcfs *fcfs;
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bufq->bq_get = bufq_fcfs_get;
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bufq->bq_put = bufq_fcfs_put;
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bufq->bq_cancel = bufq_fcfs_cancel;
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bufq->bq_fini = bufq_fcfs_fini;
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bufq->bq_private = kmem_zalloc(sizeof(struct bufq_fcfs), KM_SLEEP);
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fcfs = (struct bufq_fcfs *)bufq->bq_private;
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TAILQ_INIT(&fcfs->bq_head);
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}
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