0e5b52868f
changes. The check for nswap was bogus, but the code was so convoluted that it was difficult to tell. It's better now. :-) Reviewed by: David Greenman (extensively), and John Dyson Submitted by: Poul-Henning Kamp, w/tweaks by me.
254 lines
6.2 KiB
C
254 lines
6.2 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 1.17 1995/05/14 03:00:10 davidg 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 <vm/vm.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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#ifndef NSWAPDEV
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#define NSWAPDEV 4
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#endif
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static struct swdevt should_be_malloced[NSWAPDEV];
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struct swdevt *swdevt = should_be_malloced;
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int nswap; /* first block after the interleaved devs */
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int nswdev = NSWAPDEV;
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int vm_swap_size;
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int bswneeded;
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vm_offset_t swapbkva; /* swap buffers kva */
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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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sz = howmany(bp->b_bcount, DEV_BSIZE);
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if (nswdev > 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 % nswdev;
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seg /= nswdev;
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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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sp = &swdevt[index];
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if (bp->b_blkno + sz > sp->sw_nblks) {
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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 ((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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pbrelvp(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,i;
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struct nameidata nd;
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struct vattr attr;
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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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switch (vp->v_type) {
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case VBLK:
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dev = (dev_t) vp->v_rdev;
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if (major(dev) >= nblkdev) {
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error = ENXIO;
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break;
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}
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error = swaponvp(p, vp, dev, 0);
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break;
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case VCHR:
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/*
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* For now, we disallow swapping to regular files.
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* It requires logical->physcal block translation
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* support in the swap pager before it will work.
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*/
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error = ENOTBLK;
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break;
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#if 0
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error = VOP_GETATTR(vp, &attr, p->p_ucred, p);
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if (!error)
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error = swaponvp(p, vp, NODEV, attr.va_size / DEV_BSIZE);
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break;
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#endif
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default:
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error = EINVAL;
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break;
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}
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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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/*
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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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swaponvp(p, vp, dev, nblks)
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struct proc *p;
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struct vnode *vp;
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dev_t dev;
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u_long nblks;
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{
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int index;
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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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swblk_t dvbase;
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struct swdevt *swp;
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int error;
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int perdev;
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for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
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if (sp->sw_vp == vp)
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return EBUSY;
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if (!sp->sw_vp)
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goto found;
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}
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return EINVAL;
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found:
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if (dev != NODEV && (major(dev) >= nblkdev))
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return (ENXIO);
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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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if (nblks == 0 && (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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return (ENXIO);
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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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return (ENXIO);
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}
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sp->sw_vp = vp;
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sp->sw_dev = dev;
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sp->sw_flags |= SW_FREED;
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sp->sw_nblks = nblks;
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if (nblks * nswdev > nswap)
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nswap = (nblks+1) * nswdev;
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for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
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blk = min(nblks - dvbase,dmmax);
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vsbase = index * dmmax + dvbase * nswdev;
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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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