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freebsd/sys/vm/vm_swap.c
David Greenman 0e5b52868f Fixed a bug that managed to slip in during Poul's dynamic swap partition
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.
1995-05-18 05:09:54 +00:00

254 lines
6.2 KiB
C

/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
* $Id: vm_swap.c,v 1.17 1995/05/14 03:00:10 davidg Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/dmap.h> /* XXX */
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/rlist.h>
#include <vm/vm.h>
#include <miscfs/specfs/specdev.h>
/*
* Indirect driver for multi-controller paging.
*/
#ifndef NSWAPDEV
#define NSWAPDEV 4
#endif
static struct swdevt should_be_malloced[NSWAPDEV];
struct swdevt *swdevt = should_be_malloced;
int nswap; /* first block after the interleaved devs */
int nswdev = NSWAPDEV;
int vm_swap_size;
int bswneeded;
vm_offset_t swapbkva; /* swap buffers kva */
void
swstrategy(bp)
register struct buf *bp;
{
int sz, off, seg, index;
register struct swdevt *sp;
struct vnode *vp;
sz = howmany(bp->b_bcount, DEV_BSIZE);
if (nswdev > 1) {
off = bp->b_blkno % dmmax;
if (off + sz > dmmax) {
bp->b_error = EINVAL;
bp->b_flags |= B_ERROR;
biodone(bp);
return;
}
seg = bp->b_blkno / dmmax;
index = seg % nswdev;
seg /= nswdev;
bp->b_blkno = seg * dmmax + off;
} else
index = 0;
sp = &swdevt[index];
if (bp->b_blkno + sz > sp->sw_nblks) {
bp->b_error = EINVAL;
bp->b_flags |= B_ERROR;
biodone(bp);
return;
}
if ((bp->b_dev = sp->sw_dev) == NODEV)
panic("swstrategy");
if (sp->sw_vp == NULL) {
bp->b_error = ENODEV;
bp->b_flags |= B_ERROR;
biodone(bp);
return;
}
VHOLD(sp->sw_vp);
if ((bp->b_flags & B_READ) == 0) {
vp = bp->b_vp;
if (vp) {
vp->v_numoutput--;
if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) {
vp->v_flag &= ~VBWAIT;
wakeup((caddr_t) &vp->v_numoutput);
}
}
sp->sw_vp->v_numoutput++;
}
if (bp->b_vp != NULL)
pbrelvp(bp);
bp->b_vp = sp->sw_vp;
VOP_STRATEGY(bp);
}
/*
* System call swapon(name) enables swapping on device name,
* which must be in the swdevsw. Return EBUSY
* if already swapping on this device.
*/
struct swapon_args {
char *name;
};
/* ARGSUSED */
int
swapon(p, uap, retval)
struct proc *p;
struct swapon_args *uap;
int *retval;
{
register struct vnode *vp;
register struct swdevt *sp;
dev_t dev;
int error,i;
struct nameidata nd;
struct vattr attr;
error = suser(p->p_ucred, &p->p_acflag);
if (error)
return (error);
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, p);
error = namei(&nd);
if (error)
return (error);
vp = nd.ni_vp;
switch (vp->v_type) {
case VBLK:
dev = (dev_t) vp->v_rdev;
if (major(dev) >= nblkdev) {
error = ENXIO;
break;
}
error = swaponvp(p, vp, dev, 0);
break;
case VCHR:
/*
* For now, we disallow swapping to regular files.
* It requires logical->physcal block translation
* support in the swap pager before it will work.
*/
error = ENOTBLK;
break;
#if 0
error = VOP_GETATTR(vp, &attr, p->p_ucred, p);
if (!error)
error = swaponvp(p, vp, NODEV, attr.va_size / DEV_BSIZE);
break;
#endif
default:
error = EINVAL;
break;
}
if (error)
vrele(vp);
return (error);
}
/*
* Swfree(index) frees the index'th portion of the swap map.
* Each of the nswdev devices provides 1/nswdev'th of the swap
* space, which is laid out with blocks of dmmax pages circularly
* among the devices.
*/
int
swaponvp(p, vp, dev, nblks)
struct proc *p;
struct vnode *vp;
dev_t dev;
u_long nblks;
{
int index;
register struct swdevt *sp;
register swblk_t vsbase;
register long blk;
swblk_t dvbase;
struct swdevt *swp;
int error;
int perdev;
for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
if (sp->sw_vp == vp)
return EBUSY;
if (!sp->sw_vp)
goto found;
}
return EINVAL;
found:
if (dev != NODEV && (major(dev) >= nblkdev))
return (ENXIO);
error = VOP_OPEN(vp, FREAD | FWRITE, p->p_ucred, p);
if (error)
return (error);
if (nblks == 0 && (bdevsw[major(dev)].d_psize == 0 ||
(nblks = (*bdevsw[major(dev)].d_psize) (dev)) == -1)) {
(void) VOP_CLOSE(vp, FREAD | FWRITE, p->p_ucred, p);
return (ENXIO);
}
if (nblks == 0) {
(void) VOP_CLOSE(vp, FREAD | FWRITE, p->p_ucred, p);
return (ENXIO);
}
sp->sw_vp = vp;
sp->sw_dev = dev;
sp->sw_flags |= SW_FREED;
sp->sw_nblks = nblks;
if (nblks * nswdev > nswap)
nswap = (nblks+1) * nswdev;
for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
blk = min(nblks - dvbase,dmmax);
vsbase = index * dmmax + dvbase * nswdev;
rlist_free(&swaplist, vsbase, vsbase + blk - 1);
vm_swap_size += blk;
}
return (0);
}