268 lines
6.8 KiB
C
268 lines
6.8 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
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* 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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* from: @(#)vm_swap.c 7.18 (Berkeley) 5/6/91
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* $Id: vm_swap.c,v 1.7 1993/06/27 06:34:41 andrew Exp $
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*/
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#include "param.h"
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#include "systm.h"
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#include "buf.h"
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#include "conf.h"
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#include "proc.h"
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#include "namei.h"
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#include "dmap.h" /* XXX */
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#include "vnode.h"
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#include "specdev.h"
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#include "file.h"
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#include "rlist.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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struct rlist *swapmap = NULL;
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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 int i;
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register struct buf *sp = swbuf;
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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 this space will not be available until a swapon()
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* system is issued, usually when the system goes multi-user.
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*/
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nswdev = 0;
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nswap = 0;
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for (swp = swdevt; swp->sw_dev; 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 (bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
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panic("swapvp");
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if (error = swfree(&proc0, 0)) {
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printf("\nwarning: no swap space present (yet)\n");
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/* printf("(swfree (..., 0) -> %d)\n", error); /* XXX */
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/*panic("swapinit swfree 0");*/
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}
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/*
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* Now set up swap buffer headers.
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*/
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bswlist.av_forw = sp;
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for (i = 0; i < nswbuf - 1; i++, sp++)
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sp->av_forw = sp + 1;
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sp->av_forw = NULL;
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}
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int
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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_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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--bp->b_blkno;
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off = bp->b_blkno % dmmax;
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if (off+sz > dmmax) {
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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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++bp->b_blkno;
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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) == 0)
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panic("swstrategy");
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if (sp->sw_vp == NULL) {
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bp->b_error |= 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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if (vp = bp->b_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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/* ARGSUSED */
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swapon(p, uap, retval)
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struct proc *p;
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struct args {
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char *name;
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} *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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register struct nameidata *ndp;
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dev_t dev;
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int error;
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struct nameidata nd;
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if (error = suser(p->p_ucred, &p->p_acflag))
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return (error);
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ndp = &nd;
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ndp->ni_nameiop = LOOKUP | FOLLOW;
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ndp->ni_segflg = UIO_USERSPACE;
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ndp->ni_dirp = uap->name;
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if (error = namei(ndp, p))
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return (error);
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vp = ndp->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; sp++)
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if (sp->sw_dev == dev) {
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if (sp->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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if (error = swfree(p, sp - swdevt)) {
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printf("swapon: failed! (unchanged)\n");
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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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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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* We explicitly ignore the first block in each swap area to avoid
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* bashing a disk label and confusing the rest of the VM code.
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*/
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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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nblks = sp->sw_nblks - 1;
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if (nblks <= 0)
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return(ENXIO);
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vp = sp->sw_vp;
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if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p))
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return (error);
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sp->sw_freed = 1;
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/*printf("%d blocks from device %d/%d ",
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sp->sw_nblks, major(sp->sw_dev), minor(sp->sw_dev));*/
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for (dvbase = 0; dvbase < nblks; dvbase += dmmax) {
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blk = nblks - dvbase;
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if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap)
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panic("swfree");
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if (blk > dmmax)
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blk = dmmax;
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rlist_free(&swapmap, vsbase + 1, vsbase + blk);
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}
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return (0);
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}
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