357 lines
8.5 KiB
C
357 lines
8.5 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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* $FreeBSD$
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*/
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#include "opt_swap.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/buf.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/fcntl.h>
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#include <sys/blist.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/conf.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/swap_pager.h>
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/*
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* "sw" is a fake device implemented
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* in vm_swap.c and used only internally to get to swstrategy.
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* It cannot be provided to the users, because the
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* swstrategy routine munches the b_dev and b_blkno entries
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* before calling the appropriate driver. This would horribly
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* confuse, e.g. the hashing routines. Instead, /dev/drum is
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* provided as a character (raw) device.
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*/
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static d_strategy_t swstrategy;
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#define CDEV_MAJOR 4
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#define BDEV_MAJOR 26
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static struct cdevsw sw_cdevsw = {
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/* open */ nullopen,
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/* close */ nullclose,
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/* read */ physread,
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/* write */ physwrite,
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/* ioctl */ noioctl,
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/* stop */ nostop,
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/* reset */ noreset,
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/* devtotty */ nodevtotty,
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/* poll */ nopoll,
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/* mmap */ nommap,
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/* strategy */ swstrategy,
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/* name */ "sw",
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/* parms */ noparms,
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/* maj */ CDEV_MAJOR,
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/* dump */ nodump,
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/* psize */ nopsize,
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/* flags */ 0,
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/* maxio */ 0,
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/* bmaj */ BDEV_MAJOR
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};
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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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static struct swdevt *swdevt = should_be_malloced;
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struct vnode *swapdev_vp;
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static int nswap; /* first block after the interleaved devs */
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static int nswdev = NSWAPDEV;
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int vm_swap_size;
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/*
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* swstrategy:
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*
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* Perform swap strategy interleave device selection
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*
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* The bp is expected to be locked and *not* B_DONE on call.
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*/
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static void
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swstrategy(bp)
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register struct buf *bp;
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{
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int s, 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, PAGE_SIZE);
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/*
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* Convert interleaved swap into per-device swap. Note that
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* the block size is left in PAGE_SIZE'd chunks (for the newswap)
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* here.
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*/
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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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}
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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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bp->b_dev = sp->sw_device;
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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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/*
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* Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O
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*/
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bp->b_blkno = ctodb(bp->b_blkno);
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vhold(sp->sw_vp);
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s = splvm();
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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(&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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pbreassignbuf(bp, sp->sw_vp);
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splx(s);
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VOP_STRATEGY(bp->b_vp, 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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#ifndef _SYS_SYSPROTO_H_
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struct swapon_args {
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char *name;
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};
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#endif
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/* ARGSUSED */
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int
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swapon(p, uap)
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struct proc *p;
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struct swapon_args *uap;
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{
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register struct vnode *vp;
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dev_t dev;
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struct nameidata nd;
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int error;
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static int once;
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if (!once) {
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cdevsw_add(&sw_cdevsw);
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make_dev(&sw_cdevsw, 0, UID_ROOT, GID_KMEM, 0640, "drum");
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once++;
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}
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error = suser(p);
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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 = vp->v_rdev;
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if (devsw(dev) == NULL) {
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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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* The new swap code uses page-sized blocks. The old swap code used
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* DEV_BSIZE'd chunks.
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*
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* XXX locking when multiple swapon's run in parallel
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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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int error;
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ASSERT_VOP_UNLOCKED(vp, "swaponvp");
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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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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
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error = VOP_OPEN(vp, FREAD | FWRITE, p->p_ucred, p);
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(void) VOP_UNLOCK(vp, 0, p);
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if (error)
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return (error);
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if (nblks == 0 && dev != NODEV && (devsw(dev)->d_psize == 0 ||
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(nblks = (*devsw(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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/*
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* nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
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* First chop nblks off to page-align it, then convert.
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*
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* sw->sw_nblks is in page-sized chunks now too.
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*/
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nblks &= ~(ctodb(1) - 1);
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nblks = dbtoc(nblks);
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sp->sw_vp = vp;
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sp->sw_dev = dev2budev(dev);
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sp->sw_device = dev;
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sp->sw_flags |= SW_FREED;
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sp->sw_nblks = nblks;
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/*
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* nblks, nswap, and dmmax are PAGE_SIZE'd parameters now, not
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* DEV_BSIZE'd.
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*/
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if (nblks * nswdev > nswap)
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nswap = (nblks+1) * nswdev;
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if (swapblist == NULL)
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swapblist = blist_create(nswap);
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else
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blist_resize(&swapblist, nswap, 0);
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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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blist_free(swapblist, vsbase, blk);
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vm_swap_size += blk;
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}
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if (!swapdev_vp) {
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struct vnode *vp1;
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struct vnode *nvp;
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error = getnewvnode(VT_NON, (struct mount *) 0,
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spec_vnodeop_p, &nvp);
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if (error)
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panic("Cannot get vnode for swapdev");
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vp1 = nvp;
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vp1->v_type = VBLK;
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addaliasu(vp1, makeudev(BDEV_MAJOR, 0));
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swapdev_vp = vp1;
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}
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return (0);
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}
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