d016bf0d48
at physical block 0. Note that this will show up in pstat -s and swapinfo as space "in use". In reality, the space is simply never made available.
426 lines
11 KiB
C
426 lines
11 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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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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* @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
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* $Id: vm_swap.c,v 1.11 1994/10/22 17:53:35 phk Exp $
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*/
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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/conf.h>
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#include <sys/proc.h>
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#include <sys/namei.h>
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#include <sys/dmap.h> /* XXX */
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/rlist.h>
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#include <miscfs/specfs/specdev.h>
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/*
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* Indirect driver for multi-controller paging.
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*/
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int nswap, nswdev;
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int vm_swap_size;
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#ifdef SEQSWAP
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int niswdev; /* number of interleaved swap devices */
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int niswap; /* size of interleaved swap area */
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#endif
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int bswneeded;
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vm_offset_t swapbkva; /* swap buffers kva */
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/*
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* Set up swap devices.
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* Initialize linked list of free swap
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* headers. These do not actually point
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* to buffers, but rather to pages that
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* are being swapped in and out.
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*/
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void
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swapinit()
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{
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register struct proc *p = &proc0; /* XXX */
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struct swdevt *swp;
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int error;
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/*
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* Count swap devices, and adjust total swap space available.
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* Some of the space will not be countable until later (dynamically
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* configurable devices) and some of the counted space will not be
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* available until a swapon() system call is issued, both usually
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* happen when the system goes multi-user.
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*
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* If using NFS for swap, swdevt[0] will already be bdevvp'd. XXX
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*/
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#ifdef SEQSWAP
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nswdev = niswdev = 0;
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nswap = niswap = 0;
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/*
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* All interleaved devices must come first
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*/
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for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
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if (swp->sw_flags & SW_SEQUENTIAL)
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break;
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niswdev++;
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if (swp->sw_nblks > niswap)
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niswap = swp->sw_nblks;
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}
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niswap = roundup(niswap, dmmax);
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niswap *= niswdev;
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if (swdevt[0].sw_vp == NULL &&
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bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
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panic("swapvp");
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/*
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* The remainder must be sequential
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*/
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for ( ; swp->sw_dev != NODEV; swp++) {
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if ((swp->sw_flags & SW_SEQUENTIAL) == 0)
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panic("binit: mis-ordered swap devices");
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nswdev++;
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if (swp->sw_nblks > 0) {
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if (swp->sw_nblks % dmmax)
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swp->sw_nblks -= (swp->sw_nblks % dmmax);
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nswap += swp->sw_nblks;
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}
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}
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nswdev += niswdev;
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if (nswdev == 0)
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panic("swapinit");
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nswap += niswap;
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#else
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nswdev = 0;
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nswap = 0;
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for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
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nswdev++;
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if (swp->sw_nblks > nswap)
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nswap = swp->sw_nblks;
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}
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if (nswdev == 0)
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panic("swapinit");
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if (nswdev > 1)
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nswap = ((nswap + dmmax - 1) / dmmax) * dmmax;
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nswap *= nswdev;
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if (swdevt[0].sw_vp == NULL &&
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bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
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panic("swapvp");
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#endif
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/*
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* If there is no swap configured, tell the user. We don't automatically
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* activate any swapspaces in the kernel; the user must explicitly use
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* swapon to enable swaping on a device.
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*/
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if (nswap == 0)
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printf("WARNING: no swap space found\n");
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for (swp = swdevt; ;swp++) {
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if (swp->sw_dev == NODEV) {
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if (swp->sw_vp == NULL)
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break;
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/* We DO enable NFS swapspaces */
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error = swfree(p, swp - swdevt);
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if (error) {
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printf(
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"Couldn't enable swapspace %d, error = %d",
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swp-swdevt,error);
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}
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}
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}
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}
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void
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swstrategy(bp)
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register struct buf *bp;
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{
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int sz, off, seg, index;
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register struct swdevt *sp;
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struct vnode *vp;
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#ifdef GENERIC
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/*
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* A mini-root gets copied into the front of the swap
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* and we run over top of the swap area just long
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* enough for us to do a mkfs and restor of the real
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* root (sure beats rewriting standalone restor).
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*/
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#define MINIROOTSIZE 4096
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if (rootdev == dumpdev)
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bp->b_blkno += MINIROOTSIZE;
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#endif
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sz = howmany(bp->b_bcount, DEV_BSIZE);
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if (bp->b_blkno + sz > nswap) {
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bp->b_error = EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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if (nswdev > 1) {
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#ifdef SEQSWAP
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if (bp->b_blkno < niswap) {
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if (niswdev > 1) {
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off = bp->b_blkno % dmmax;
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if (off+sz > dmmax) {
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bp->b_error = EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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seg = bp->b_blkno / dmmax;
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index = seg % niswdev;
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seg /= niswdev;
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bp->b_blkno = seg*dmmax + off;
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} else
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index = 0;
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} else {
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register struct swdevt *swp;
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bp->b_blkno -= niswap;
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for (index = niswdev, swp = &swdevt[niswdev];
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swp->sw_dev != NODEV;
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swp++, index++) {
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if (bp->b_blkno < swp->sw_nblks)
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break;
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bp->b_blkno -= swp->sw_nblks;
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}
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if (swp->sw_dev == NODEV ||
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bp->b_blkno+sz > swp->sw_nblks) {
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bp->b_error = swp->sw_dev == NODEV ?
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ENODEV : EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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}
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#else
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off = bp->b_blkno % dmmax;
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if (off+sz > dmmax) {
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bp->b_error = EINVAL;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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seg = bp->b_blkno / dmmax;
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index = seg % nswdev;
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seg /= nswdev;
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bp->b_blkno = seg*dmmax + off;
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#endif
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} else
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index = 0;
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sp = &swdevt[index];
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if ((bp->b_dev = sp->sw_dev) == NODEV)
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panic("swstrategy");
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if (sp->sw_vp == NULL) {
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bp->b_error = ENODEV;
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bp->b_flags |= B_ERROR;
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biodone(bp);
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return;
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}
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VHOLD(sp->sw_vp);
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if ((bp->b_flags & B_READ) == 0) {
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vp = bp->b_vp;
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if (vp) {
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vp->v_numoutput--;
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if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) {
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vp->v_flag &= ~VBWAIT;
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wakeup((caddr_t)&vp->v_numoutput);
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}
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}
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sp->sw_vp->v_numoutput++;
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}
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if (bp->b_vp != NULL)
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brelvp(bp);
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bp->b_vp = sp->sw_vp;
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VOP_STRATEGY(bp);
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}
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/*
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* System call swapon(name) enables swapping on device name,
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* which must be in the swdevsw. Return EBUSY
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* if already swapping on this device.
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*/
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struct swapon_args {
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char *name;
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};
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/* ARGSUSED */
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int
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swapon(p, uap, retval)
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struct proc *p;
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struct swapon_args *uap;
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int *retval;
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{
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register struct vnode *vp;
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register struct swdevt *sp;
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dev_t dev;
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int error;
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struct nameidata nd;
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error = suser(p->p_ucred, &p->p_acflag);
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if (error)
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return (error);
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, p);
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error = namei(&nd);
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if (error)
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return (error);
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vp = nd.ni_vp;
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if (vp->v_type != VBLK) {
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vrele(vp);
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return (ENOTBLK);
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}
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dev = (dev_t)vp->v_rdev;
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if (major(dev) >= nblkdev) {
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vrele(vp);
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return (ENXIO);
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}
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for (sp = &swdevt[0]; sp->sw_dev != NODEV; sp++) {
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if (sp->sw_dev == dev) {
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if (sp->sw_flags & SW_FREED) {
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vrele(vp);
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return (EBUSY);
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}
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sp->sw_vp = vp;
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error = swfree(p, sp - swdevt);
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if (error) {
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vrele(vp);
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return (error);
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}
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return (0);
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}
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#ifdef SEQSWAP
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/*
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* If we have reached a non-freed sequential device without
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* finding what we are looking for, it is an error.
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* That is because all interleaved devices must come first
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* and sequential devices must be freed in order.
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*/
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if ((sp->sw_flags & (SW_SEQUENTIAL|SW_FREED)) == SW_SEQUENTIAL)
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break;
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#endif
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}
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vrele(vp);
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return (EINVAL);
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}
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/*
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* Swfree(index) frees the index'th portion of the swap map.
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* Each of the nswdev devices provides 1/nswdev'th of the swap
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* space, which is laid out with blocks of dmmax pages circularly
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* among the devices.
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*/
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int
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swfree(p, index)
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struct proc *p;
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int index;
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{
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register struct swdevt *sp;
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register swblk_t vsbase;
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register long blk;
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struct vnode *vp;
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register swblk_t dvbase;
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register int nblks;
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int error;
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sp = &swdevt[index];
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vp = sp->sw_vp;
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error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p);
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if (error)
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return (error);
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sp->sw_flags |= SW_FREED;
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nblks = sp->sw_nblks;
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/*
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* Some devices may not exist til after boot time.
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* If so, their nblk count will be 0.
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*/
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if (nblks <= 0) {
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int perdev;
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dev_t dev = sp->sw_dev;
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if (bdevsw[major(dev)].d_psize == 0 ||
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(nblks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) {
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(void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
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sp->sw_flags &= ~SW_FREED;
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return (ENXIO);
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}
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#ifdef SEQSWAP
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if (index < niswdev) {
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perdev = niswap / niswdev;
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if (nblks > perdev)
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nblks = perdev;
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} else {
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if (nblks % dmmax)
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nblks -= (nblks % dmmax);
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nswap += nblks;
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}
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#else
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perdev = nswap / nswdev;
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if (nblks > perdev)
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nblks = perdev;
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#endif
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sp->sw_nblks = nblks;
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}
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if (nblks == 0) {
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(void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
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sp->sw_flags &= ~SW_FREED;
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return (0); /* XXX error? */
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}
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#ifdef SEQSWAP
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if (sp->sw_flags & SW_SEQUENTIAL) {
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register struct swdevt *swp;
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blk = niswap;
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for (swp = &swdevt[niswdev]; swp != sp; swp++)
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blk += swp->sw_nblks;
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rlist_free(&swaplist, blk, blk + nblks - 1);
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vm_swap_size += nblks;
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return (0);
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}
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#endif
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for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
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blk = nblks - dvbase;
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#ifdef SEQSWAP
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if ((vsbase = index*dmmax + dvbase*niswdev) >= niswap)
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panic("swfree");
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#else
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if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap)
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panic("swfree");
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#endif
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if (blk > dmmax)
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blk = dmmax;
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/* XXX -- we need to exclude the first cluster as above */
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/* but for now, this will work fine... */
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rlist_free(&swaplist, vsbase, vsbase + blk - 1);
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vm_swap_size += blk;
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}
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return (0);
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}
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