1008 lines
27 KiB
C
1008 lines
27 KiB
C
/* $NetBSD: subr_disk.c,v 1.41 2002/07/23 14:00:16 hannken 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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: subr_disk.c,v 1.41 2002/07/23 14:00:16 hannken Exp $");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/buf.h>
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#include <sys/syslog.h>
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#include <sys/disklabel.h>
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#include <sys/disk.h>
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#include <sys/sysctl.h>
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/*
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* A global list of all disks attached to the system. May grow or
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* shrink over time.
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*/
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struct disklist_head disklist; /* TAILQ_HEAD */
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int disk_count; /* number of drives in global disklist */
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struct simplelock disklist_slock = SIMPLELOCK_INITIALIZER;
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/*
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* XXX This interface will be removed in the near future!
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*
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* Seek sort for disks. We depend on the driver which calls us using b_resid
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* as the current cylinder number.
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*
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* The argument bufq is an I/O queue for the device, on which there are
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* actually two queues, sorted in ascending cylinder order. The first
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* queue holds those requests which are positioned after the current
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* cylinder (in the first request); the second holds requests which came
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* in after their cylinder number was passed. Thus we implement a one-way
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* scan, retracting after reaching the end of the drive to the first request
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* on the second queue, at which time it becomes the first queue.
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*
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* A one-way scan is natural because of the way UNIX read-ahead blocks are
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* allocated.
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*
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* This is further adjusted by any `barriers' which may exist in the queue.
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* The bufq points to the last such ordered request.
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*/
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void
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disksort_cylinder(struct buf_queue *bufq, struct buf *bp)
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{
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struct buf *bq, *nbq;
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/*
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* If there are ordered requests on the queue, we must start
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* the elevator sort after the last of these.
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*/
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if ((bq = bufq->bq_barrier) == NULL)
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bq = BUFQ_FIRST(bufq);
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/*
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* If the queue is empty, of if it's an ordered request,
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* it's easy; we just go on the end.
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*/
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if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
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BUFQ_INSERT_TAIL(bufq, bp);
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return;
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}
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/*
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* If we lie after the first (currently active) request, then we
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* must locate the second request list and add ourselves to it.
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*/
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if (bp->b_cylinder < bq->b_cylinder ||
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(bp->b_cylinder == bq->b_cylinder &&
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bp->b_rawblkno < bq->b_rawblkno)) {
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while ((nbq = BUFQ_NEXT(bq)) != NULL) {
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/*
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* Check for an ``inversion'' in the normally ascending
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* cylinder numbers, indicating the start of the second
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* request list.
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*/
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if (nbq->b_cylinder < bq->b_cylinder) {
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/*
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* Search the second request list for the first
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* request at a larger cylinder number. We go
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* before that; if there is no such request, we
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* go at end.
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*/
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do {
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if (bp->b_cylinder < nbq->b_cylinder)
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goto insert;
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if (bp->b_cylinder == nbq->b_cylinder &&
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bp->b_rawblkno < nbq->b_rawblkno)
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goto insert;
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bq = nbq;
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} while ((nbq = BUFQ_NEXT(bq)) != NULL);
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goto insert; /* after last */
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}
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bq = nbq;
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}
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/*
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* No inversions... we will go after the last, and
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* be the first request in the second request list.
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*/
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goto insert;
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}
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/*
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* Request is at/after the current request...
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* sort in the first request list.
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*/
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while ((nbq = BUFQ_NEXT(bq)) != NULL) {
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/*
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* We want to go after the current request if there is an
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* inversion after it (i.e. it is the end of the first
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* request list), or if the next request is a larger cylinder
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* than our request.
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*/
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if (nbq->b_cylinder < bq->b_cylinder ||
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bp->b_cylinder < nbq->b_cylinder ||
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(bp->b_cylinder == nbq->b_cylinder &&
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bp->b_rawblkno < nbq->b_rawblkno))
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goto insert;
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bq = nbq;
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}
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/*
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* Neither a second list nor a larger request... we go at the end of
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* the first list, which is the same as the end of the whole schebang.
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*/
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insert: BUFQ_INSERT_AFTER(bufq, bq, bp);
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}
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/*
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* Seek sort for disks. This version sorts based on b_rawblkno, which
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* indicates the block number.
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*
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* As before, there are actually two queues, sorted in ascendening block
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* order. The first queue holds those requests which are positioned after
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* the current block (in the first request); the second holds requests which
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* came in after their block number was passed. Thus we implement a one-way
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* scan, retracting after reaching the end of the driver to the first request
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* on the second queue, at which time it becomes the first queue.
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*
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* A one-way scan is natural because of the way UNIX read-ahead blocks are
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* allocated.
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*
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* This is further adjusted by any `barriers' which may exist in the queue.
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* The bufq points to the last such ordered request.
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*/
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void
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disksort_blkno(struct buf_queue *bufq, struct buf *bp)
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{
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struct buf *bq, *nbq;
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/*
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* If there are ordered requests on the queue, we must start
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* the elevator sort after the last of these.
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*/
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if ((bq = bufq->bq_barrier) == NULL)
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bq = BUFQ_FIRST(bufq);
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/*
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* If the queue is empty, or if it's an ordered request,
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* it's easy; we just go on the end.
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*/
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if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
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BUFQ_INSERT_TAIL(bufq, bp);
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return;
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}
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/*
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* If we lie after the first (currently active) request, then we
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* must locate the second request list and add ourselves to it.
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*/
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if (bp->b_rawblkno < bq->b_rawblkno) {
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while ((nbq = BUFQ_NEXT(bq)) != NULL) {
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/*
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* Check for an ``inversion'' in the normally ascending
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* block numbers, indicating the start of the second
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* request list.
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*/
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if (nbq->b_rawblkno < bq->b_rawblkno) {
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/*
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* Search the second request list for the first
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* request at a larger block number. We go
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* after that; if there is no such request, we
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* go at the end.
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*/
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do {
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if (bp->b_rawblkno < nbq->b_rawblkno)
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goto insert;
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bq = nbq;
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} while ((nbq = BUFQ_NEXT(bq)) != NULL);
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goto insert; /* after last */
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}
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bq = nbq;
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}
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/*
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* No inversions... we will go after the last, and
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* be the first request in the second request list.
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*/
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goto insert;
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}
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/*
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* Request is at/after the current request...
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* sort in the first request list.
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*/
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while ((nbq = BUFQ_NEXT(bq)) != NULL) {
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/*
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* We want to go after the current request if there is an
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* inversion after it (i.e. it is the end of the first
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* request list), or if the next request is a larger cylinder
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* than our request.
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*/
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if (nbq->b_rawblkno < bq->b_rawblkno ||
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bp->b_rawblkno < nbq->b_rawblkno)
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goto insert;
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bq = nbq;
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}
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/*
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* Neither a second list nor a larger request... we go at the end of
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* the first list, which is the same as the end of the whole schebang.
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*/
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insert: BUFQ_INSERT_AFTER(bufq, bq, bp);
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}
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/*
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* Seek non-sort for disks. This version simply inserts requests at
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* the tail of the queue.
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*/
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void
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disksort_tail(struct buf_queue *bufq, struct buf *bp)
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{
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BUFQ_INSERT_TAIL(bufq, bp);
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}
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/*
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* XXX End of to be removed interface!
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*/
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/*
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* Compute checksum for disk label.
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*/
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u_int
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dkcksum(struct disklabel *lp)
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{
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u_short *start, *end;
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u_short sum = 0;
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start = (u_short *)lp;
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end = (u_short *)&lp->d_partitions[lp->d_npartitions];
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while (start < end)
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sum ^= *start++;
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return (sum);
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}
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/*
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* Disk error is the preface to plaintive error messages
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* about failing disk transfers. It prints messages of the form
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hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
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* if the offset of the error in the transfer and a disk label
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* are both available. blkdone should be -1 if the position of the error
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* is unknown; the disklabel pointer may be null from drivers that have not
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* been converted to use them. The message is printed with printf
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* if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
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* The message should be completed (with at least a newline) with printf
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* or addlog, respectively. There is no trailing space.
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*/
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void
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diskerr(const struct buf *bp, const char *dname, const char *what, int pri,
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int blkdone, const struct disklabel *lp)
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{
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int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
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void (*pr)(const char *, ...);
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char partname = 'a' + part;
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int sn;
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if (pri != LOG_PRINTF) {
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static const char fmt[] = "";
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log(pri, fmt);
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pr = addlog;
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} else
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pr = printf;
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(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
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bp->b_flags & B_READ ? "read" : "writ");
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sn = bp->b_blkno;
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if (bp->b_bcount <= DEV_BSIZE)
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(*pr)("%d", sn);
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else {
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if (blkdone >= 0) {
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sn += blkdone;
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(*pr)("%d of ", sn);
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}
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(*pr)("%d-%d", bp->b_blkno,
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bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
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}
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if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
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sn += lp->d_partitions[part].p_offset;
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(*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
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sn / lp->d_secpercyl);
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sn %= lp->d_secpercyl;
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(*pr)(" tn %d sn %d)", sn / lp->d_nsectors,
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sn % lp->d_nsectors);
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}
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}
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/*
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* Initialize the disklist. Called by main() before autoconfiguration.
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*/
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void
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disk_init(void)
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{
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TAILQ_INIT(&disklist);
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disk_count = 0;
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}
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/*
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* Searches the disklist for the disk corresponding to the
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* name provided.
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*/
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struct disk *
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disk_find(char *name)
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{
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struct disk *diskp;
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if ((name == NULL) || (disk_count <= 0))
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return (NULL);
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simple_lock(&disklist_slock);
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for (diskp = TAILQ_FIRST(&disklist); diskp != NULL;
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diskp = TAILQ_NEXT(diskp, dk_link))
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if (strcmp(diskp->dk_name, name) == 0) {
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simple_unlock(&disklist_slock);
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return (diskp);
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}
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simple_unlock(&disklist_slock);
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return (NULL);
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}
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/*
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* Attach a disk.
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*/
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void
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disk_attach(struct disk *diskp)
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{
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int s;
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/*
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* Allocate and initialize the disklabel structures. Note that
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* it's not safe to sleep here, since we're probably going to be
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* called during autoconfiguration.
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*/
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diskp->dk_label = malloc(sizeof(struct disklabel), M_DEVBUF, M_NOWAIT);
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diskp->dk_cpulabel = malloc(sizeof(struct cpu_disklabel), M_DEVBUF,
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M_NOWAIT);
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if ((diskp->dk_label == NULL) || (diskp->dk_cpulabel == NULL))
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panic("disk_attach: can't allocate storage for disklabel");
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memset(diskp->dk_label, 0, sizeof(struct disklabel));
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memset(diskp->dk_cpulabel, 0, sizeof(struct cpu_disklabel));
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/*
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* Set the attached timestamp.
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*/
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s = splclock();
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diskp->dk_attachtime = mono_time;
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splx(s);
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/*
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* Link into the disklist.
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*/
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simple_lock(&disklist_slock);
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TAILQ_INSERT_TAIL(&disklist, diskp, dk_link);
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simple_unlock(&disklist_slock);
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++disk_count;
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}
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/*
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* Detach a disk.
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*/
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void
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disk_detach(struct disk *diskp)
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{
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/*
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* Remove from the disklist.
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*/
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if (--disk_count < 0)
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panic("disk_detach: disk_count < 0");
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simple_lock(&disklist_slock);
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TAILQ_REMOVE(&disklist, diskp, dk_link);
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simple_unlock(&disklist_slock);
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/*
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* Free the space used by the disklabel structures.
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*/
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free(diskp->dk_label, M_DEVBUF);
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free(diskp->dk_cpulabel, M_DEVBUF);
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}
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/*
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* Increment a disk's busy counter. If the counter is going from
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* 0 to 1, set the timestamp.
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*/
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void
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disk_busy(struct disk *diskp)
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{
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int s;
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/*
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* XXX We'd like to use something as accurate as microtime(),
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* but that doesn't depend on the system TOD clock.
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*/
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if (diskp->dk_busy++ == 0) {
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s = splclock();
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diskp->dk_timestamp = mono_time;
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splx(s);
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}
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}
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/*
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* Decrement a disk's busy counter, increment the byte count, total busy
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* time, and reset the timestamp.
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*/
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void
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disk_unbusy(struct disk *diskp, long bcount)
|
|
{
|
|
int s;
|
|
struct timeval dv_time, diff_time;
|
|
|
|
if (diskp->dk_busy-- == 0) {
|
|
printf("%s: dk_busy < 0\n", diskp->dk_name);
|
|
panic("disk_unbusy");
|
|
}
|
|
|
|
s = splclock();
|
|
dv_time = mono_time;
|
|
splx(s);
|
|
|
|
timersub(&dv_time, &diskp->dk_timestamp, &diff_time);
|
|
timeradd(&diskp->dk_time, &diff_time, &diskp->dk_time);
|
|
|
|
diskp->dk_timestamp = dv_time;
|
|
if (bcount > 0) {
|
|
diskp->dk_bytes += bcount;
|
|
diskp->dk_xfer++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Reset the metrics counters on the given disk. Note that we cannot
|
|
* reset the busy counter, as it may case a panic in disk_unbusy().
|
|
* We also must avoid playing with the timestamp information, as it
|
|
* may skew any pending transfer results.
|
|
*/
|
|
void
|
|
disk_resetstat(struct disk *diskp)
|
|
{
|
|
int s = splbio(), t;
|
|
|
|
diskp->dk_xfer = 0;
|
|
diskp->dk_bytes = 0;
|
|
|
|
t = splclock();
|
|
diskp->dk_attachtime = mono_time;
|
|
splx(t);
|
|
|
|
timerclear(&diskp->dk_time);
|
|
|
|
splx(s);
|
|
}
|
|
|
|
int
|
|
sysctl_disknames(void *vwhere, size_t *sizep)
|
|
{
|
|
char buf[DK_DISKNAMELEN + 1];
|
|
char *where = vwhere;
|
|
struct disk *diskp;
|
|
size_t needed, left, slen;
|
|
int error, first;
|
|
|
|
first = 1;
|
|
error = 0;
|
|
needed = 0;
|
|
left = *sizep;
|
|
|
|
simple_lock(&disklist_slock);
|
|
for (diskp = TAILQ_FIRST(&disklist); diskp != NULL;
|
|
diskp = TAILQ_NEXT(diskp, dk_link)) {
|
|
if (where == NULL)
|
|
needed += strlen(diskp->dk_name) + 1;
|
|
else {
|
|
memset(buf, 0, sizeof(buf));
|
|
if (first) {
|
|
strncpy(buf, diskp->dk_name, sizeof(buf));
|
|
first = 0;
|
|
} else {
|
|
buf[0] = ' ';
|
|
strncpy(buf + 1, diskp->dk_name,
|
|
sizeof(buf) - 1);
|
|
}
|
|
buf[DK_DISKNAMELEN] = '\0';
|
|
slen = strlen(buf);
|
|
if (left < slen + 1)
|
|
break;
|
|
/* +1 to copy out the trailing NUL byte */
|
|
error = copyout(buf, where, slen + 1);
|
|
if (error)
|
|
break;
|
|
where += slen;
|
|
needed += slen;
|
|
left -= slen;
|
|
}
|
|
}
|
|
simple_unlock(&disklist_slock);
|
|
*sizep = needed;
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
sysctl_diskstats(int *name, u_int namelen, void *vwhere, size_t *sizep)
|
|
{
|
|
struct disk_sysctl sdisk;
|
|
struct disk *diskp;
|
|
char *where = vwhere;
|
|
size_t tocopy, left;
|
|
int error;
|
|
|
|
if (where == NULL) {
|
|
*sizep = disk_count * sizeof(struct disk_sysctl);
|
|
return (0);
|
|
}
|
|
|
|
if (namelen == 0)
|
|
tocopy = sizeof(sdisk);
|
|
else
|
|
tocopy = name[0];
|
|
|
|
error = 0;
|
|
left = *sizep;
|
|
memset(&sdisk, 0, sizeof(sdisk));
|
|
*sizep = 0;
|
|
|
|
simple_lock(&disklist_slock);
|
|
TAILQ_FOREACH(diskp, &disklist, dk_link) {
|
|
if (left < sizeof(struct disk_sysctl))
|
|
break;
|
|
strncpy(sdisk.dk_name, diskp->dk_name, sizeof(sdisk.dk_name));
|
|
sdisk.dk_xfer = diskp->dk_xfer;
|
|
sdisk.dk_seek = diskp->dk_seek;
|
|
sdisk.dk_bytes = diskp->dk_bytes;
|
|
sdisk.dk_attachtime_sec = diskp->dk_attachtime.tv_sec;
|
|
sdisk.dk_attachtime_usec = diskp->dk_attachtime.tv_usec;
|
|
sdisk.dk_timestamp_sec = diskp->dk_timestamp.tv_sec;
|
|
sdisk.dk_timestamp_usec = diskp->dk_timestamp.tv_usec;
|
|
sdisk.dk_time_sec = diskp->dk_time.tv_sec;
|
|
sdisk.dk_time_usec = diskp->dk_time.tv_usec;
|
|
sdisk.dk_busy = diskp->dk_busy;
|
|
|
|
error = copyout(&sdisk, where, min(tocopy, sizeof(sdisk)));
|
|
if (error)
|
|
break;
|
|
where += tocopy;
|
|
*sizep += tocopy;
|
|
left -= tocopy;
|
|
}
|
|
simple_unlock(&disklist_slock);
|
|
return (error);
|
|
}
|
|
|
|
|
|
struct bufq_fcfs {
|
|
TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
|
|
};
|
|
|
|
struct bufq_disksort {
|
|
TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
|
|
};
|
|
|
|
#define PRIO_READ_BURST 48
|
|
#define PRIO_WRITE_REQ 16
|
|
|
|
struct bufq_prio {
|
|
TAILQ_HEAD(, buf) bq_read, bq_write; /* actual list of buffers */
|
|
struct buf *bq_write_next; /* next request in bq_write */
|
|
struct buf *bq_next; /* current request */
|
|
int bq_read_burst; /* # of consecutive reads */
|
|
};
|
|
|
|
|
|
/*
|
|
* Check if two buf's are in ascending order.
|
|
*/
|
|
static __inline int
|
|
buf_inorder(struct buf *bp, struct buf *bq, int sortby)
|
|
{
|
|
int r;
|
|
|
|
if (bp == NULL || bq == NULL)
|
|
return(bq == NULL);
|
|
|
|
if (sortby == BUFQ_SORT_CYLINDER)
|
|
r = bp->b_cylinder - bq->b_cylinder;
|
|
else
|
|
r = 0;
|
|
|
|
if (r == 0)
|
|
r = bp->b_rawblkno - bq->b_rawblkno;
|
|
|
|
return(r <= 0);
|
|
}
|
|
|
|
|
|
/*
|
|
* First-come first-served sort for disks.
|
|
*
|
|
* Requests are appended to the queue without any reordering.
|
|
*/
|
|
static void
|
|
bufq_fcfs_put(struct bufq_state *bufq, struct buf *bp)
|
|
{
|
|
struct bufq_fcfs *fcfs = bufq->bq_private;
|
|
|
|
TAILQ_INSERT_TAIL(&fcfs->bq_head, bp, b_actq);
|
|
}
|
|
|
|
static struct buf *
|
|
bufq_fcfs_get(struct bufq_state *bufq, int remove)
|
|
{
|
|
struct bufq_fcfs *fcfs = bufq->bq_private;
|
|
struct buf *bp;
|
|
|
|
bp = TAILQ_FIRST(&fcfs->bq_head);
|
|
|
|
if (bp != NULL && remove)
|
|
TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
|
|
|
|
return(bp);
|
|
}
|
|
|
|
|
|
/*
|
|
* Seek sort for disks.
|
|
*
|
|
* There are actually two queues, sorted in ascendening order. The first
|
|
* queue holds those requests which are positioned after the current block;
|
|
* the second holds requests which came in after their position was passed.
|
|
* Thus we implement a one-way scan, retracting after reaching the end of
|
|
* the drive to the first request on the second queue, at which time it
|
|
* becomes the first queue.
|
|
*
|
|
* A one-way scan is natural because of the way UNIX read-ahead blocks are
|
|
* allocated.
|
|
*/
|
|
static void
|
|
bufq_disksort_put(struct bufq_state *bufq, struct buf *bp)
|
|
{
|
|
struct bufq_disksort *disksort = bufq->bq_private;
|
|
struct buf *bq, *nbq;
|
|
int sortby;
|
|
|
|
sortby = bufq->bq_flags & BUFQ_SORT_MASK;
|
|
|
|
bq = TAILQ_FIRST(&disksort->bq_head);
|
|
|
|
/*
|
|
* If the queue is empty it's easy; we just go on the end.
|
|
*/
|
|
if (bq == NULL) {
|
|
TAILQ_INSERT_TAIL(&disksort->bq_head, bp, b_actq);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If we lie before the currently active request, then we
|
|
* must locate the second request list and add ourselves to it.
|
|
*/
|
|
if (buf_inorder(bp, bq, sortby)) {
|
|
while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) {
|
|
/*
|
|
* Check for an ``inversion'' in the normally ascending
|
|
* block numbers, indicating the start of the second
|
|
* request list.
|
|
*/
|
|
if (buf_inorder(nbq, bq, sortby)) {
|
|
/*
|
|
* Search the second request list for the first
|
|
* request at a larger block number. We go
|
|
* after that; if there is no such request, we
|
|
* go at the end.
|
|
*/
|
|
do {
|
|
if (buf_inorder(bp, nbq, sortby))
|
|
goto insert;
|
|
bq = nbq;
|
|
} while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL);
|
|
goto insert; /* after last */
|
|
}
|
|
bq = nbq;
|
|
}
|
|
/*
|
|
* No inversions... we will go after the last, and
|
|
* be the first request in the second request list.
|
|
*/
|
|
goto insert;
|
|
}
|
|
/*
|
|
* Request is at/after the current request...
|
|
* sort in the first request list.
|
|
*/
|
|
while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) {
|
|
/*
|
|
* We want to go after the current request if there is an
|
|
* inversion after it (i.e. it is the end of the first
|
|
* request list), or if the next request is a larger cylinder
|
|
* than our request.
|
|
*/
|
|
if (buf_inorder(nbq, bq, sortby) ||
|
|
buf_inorder(bp, nbq, sortby))
|
|
goto insert;
|
|
bq = nbq;
|
|
}
|
|
/*
|
|
* Neither a second list nor a larger request... we go at the end of
|
|
* the first list, which is the same as the end of the whole schebang.
|
|
*/
|
|
insert: TAILQ_INSERT_AFTER(&disksort->bq_head, bq, bp, b_actq);
|
|
}
|
|
|
|
static struct buf *
|
|
bufq_disksort_get(struct bufq_state *bufq, int remove)
|
|
{
|
|
struct bufq_disksort *disksort = bufq->bq_private;
|
|
struct buf *bp;
|
|
|
|
bp = TAILQ_FIRST(&disksort->bq_head);
|
|
|
|
if (bp != NULL && remove)
|
|
TAILQ_REMOVE(&disksort->bq_head, bp, b_actq);
|
|
|
|
return(bp);
|
|
}
|
|
|
|
|
|
/*
|
|
* Seek sort for disks.
|
|
*
|
|
* There are two queues. The first queue holds read requests; the second
|
|
* holds write requests. The read queue is first-come first-served; the
|
|
* write queue is sorted in ascendening block order.
|
|
* The read queue is processed first. After PRIO_READ_BURST consecutive
|
|
* read requests with non-empty write queue PRIO_WRITE_REQ requests from
|
|
* the write queue will be processed.
|
|
*/
|
|
static void
|
|
bufq_prio_put(struct bufq_state *bufq, struct buf *bp)
|
|
{
|
|
struct bufq_prio *prio = bufq->bq_private;
|
|
struct buf *bq;
|
|
int sortby;
|
|
|
|
sortby = bufq->bq_flags & BUFQ_SORT_MASK;
|
|
|
|
/*
|
|
* If it's a read request append it to the list.
|
|
*/
|
|
if ((bp->b_flags & B_READ) == B_READ) {
|
|
TAILQ_INSERT_TAIL(&prio->bq_read, bp, b_actq);
|
|
return;
|
|
}
|
|
|
|
bq = TAILQ_FIRST(&prio->bq_write);
|
|
|
|
/*
|
|
* If the write list is empty, simply append it to the list.
|
|
*/
|
|
if (bq == NULL) {
|
|
TAILQ_INSERT_TAIL(&prio->bq_write, bp, b_actq);
|
|
prio->bq_write_next = bp;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If we lie after the next request, insert after this request.
|
|
*/
|
|
if (buf_inorder(prio->bq_write_next, bp, sortby))
|
|
bq = prio->bq_write_next;
|
|
|
|
/*
|
|
* Search for the first request at a larger block number.
|
|
* We go before this request if it exists.
|
|
*/
|
|
while (bq != NULL && buf_inorder(bq, bp, sortby))
|
|
bq = TAILQ_NEXT(bq, b_actq);
|
|
|
|
if (bq != NULL)
|
|
TAILQ_INSERT_BEFORE(bq, bp, b_actq);
|
|
else
|
|
TAILQ_INSERT_TAIL(&prio->bq_write, bp, b_actq);
|
|
}
|
|
|
|
static struct buf *
|
|
bufq_prio_get(struct bufq_state *bufq, int remove)
|
|
{
|
|
struct bufq_prio *prio = bufq->bq_private;
|
|
struct buf *bp;
|
|
|
|
/*
|
|
* If no current request, get next from the lists.
|
|
*/
|
|
if (prio->bq_next == NULL) {
|
|
/*
|
|
* If at least one list is empty, select the other.
|
|
*/
|
|
|
|
if (TAILQ_FIRST(&prio->bq_read) == NULL) {
|
|
prio->bq_next = prio->bq_write_next;
|
|
prio->bq_read_burst = 0;
|
|
} else if (prio->bq_write_next == NULL) {
|
|
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
|
|
prio->bq_read_burst = 0;
|
|
} else {
|
|
/*
|
|
* Both list have requests. Select the read list up
|
|
* to PRIO_READ_BURST times, then select the write
|
|
* list PRIO_WRITE_REQ times.
|
|
*/
|
|
|
|
if (prio->bq_read_burst++ < PRIO_READ_BURST)
|
|
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
|
|
else if (prio->bq_read_burst <
|
|
PRIO_READ_BURST + PRIO_WRITE_REQ)
|
|
prio->bq_next = prio->bq_write_next;
|
|
else {
|
|
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
|
|
prio->bq_read_burst = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
bp = prio->bq_next;
|
|
|
|
if (prio->bq_next != NULL && remove) {
|
|
if ((prio->bq_next->b_flags & B_READ) == B_READ)
|
|
TAILQ_REMOVE(&prio->bq_read, prio->bq_next, b_actq);
|
|
else {
|
|
TAILQ_REMOVE(&prio->bq_write, prio->bq_next, b_actq);
|
|
/*
|
|
* Advance the write pointer.
|
|
*/
|
|
prio->bq_write_next =
|
|
TAILQ_NEXT(prio->bq_write_next, b_actq);
|
|
if (prio->bq_write_next == NULL)
|
|
prio->bq_write_next =
|
|
TAILQ_FIRST(&prio->bq_write);
|
|
}
|
|
|
|
prio->bq_next = NULL;
|
|
}
|
|
|
|
return(bp);
|
|
}
|
|
|
|
/*
|
|
* Create a device buffer queue.
|
|
*/
|
|
void
|
|
bufq_alloc(struct bufq_state *bufq, int flags)
|
|
{
|
|
struct bufq_fcfs *fcfs;
|
|
struct bufq_disksort *disksort;
|
|
struct bufq_prio *prio;
|
|
|
|
bufq->bq_flags = flags;
|
|
|
|
switch (flags & BUFQ_SORT_MASK) {
|
|
case BUFQ_SORT_RAWBLOCK:
|
|
case BUFQ_SORT_CYLINDER:
|
|
break;
|
|
case 0:
|
|
if ((flags & BUFQ_METHOD_MASK) == BUFQ_FCFS)
|
|
break;
|
|
/* FALLTHROUGH */
|
|
default:
|
|
panic("bufq_alloc: sort out of range");
|
|
}
|
|
|
|
switch (flags & BUFQ_METHOD_MASK) {
|
|
case BUFQ_FCFS:
|
|
bufq->bq_get = bufq_fcfs_get;
|
|
bufq->bq_put = bufq_fcfs_put;
|
|
MALLOC(bufq->bq_private, struct bufq_fcfs *,
|
|
sizeof(struct bufq_fcfs), M_DEVBUF, M_ZERO);
|
|
fcfs = (struct bufq_fcfs *)bufq->bq_private;
|
|
TAILQ_INIT(&fcfs->bq_head);
|
|
break;
|
|
case BUFQ_DISKSORT:
|
|
bufq->bq_get = bufq_disksort_get;
|
|
bufq->bq_put = bufq_disksort_put;
|
|
MALLOC(bufq->bq_private, struct bufq_disksort *,
|
|
sizeof(struct bufq_disksort), M_DEVBUF, M_ZERO);
|
|
disksort = (struct bufq_disksort *)bufq->bq_private;
|
|
TAILQ_INIT(&disksort->bq_head);
|
|
break;
|
|
case BUFQ_READ_PRIO:
|
|
bufq->bq_get = bufq_prio_get;
|
|
bufq->bq_put = bufq_prio_put;
|
|
MALLOC(bufq->bq_private, struct bufq_prio *,
|
|
sizeof(struct bufq_prio), M_DEVBUF, M_ZERO);
|
|
prio = (struct bufq_prio *)bufq->bq_private;
|
|
TAILQ_INIT(&prio->bq_read);
|
|
TAILQ_INIT(&prio->bq_write);
|
|
break;
|
|
default:
|
|
panic("bufq_alloc: method out of range");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Destroy a device buffer queue.
|
|
*/
|
|
void
|
|
bufq_free(struct bufq_state *bufq)
|
|
{
|
|
KASSERT(bufq->bq_private != NULL);
|
|
KASSERT(BUFQ_PEEK(bufq) == NULL);
|
|
|
|
FREE(bufq->bq_private, M_DEVBUF);
|
|
bufq->bq_get = NULL;
|
|
bufq->bq_put = NULL;
|
|
}
|