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-rw-r--r--sys/vm/vm_swap.c480
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diff --git a/sys/vm/vm_swap.c b/sys/vm/vm_swap.c
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+/* $NetBSD: vm_swap.c,v 1.31 1995/10/07 06:29:02 mycroft Exp $ */
+
+/*
+ * 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
+ */
+
+#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/map.h>
+#include <sys/file.h>
+
+#include <sys/mount.h>
+#include <sys/syscallargs.h>
+
+#include <miscfs/specfs/specdev.h>
+
+/*
+ * Indirect driver for multi-controller paging.
+ */
+
+int nswap, nswdev;
+#ifdef SEQSWAP
+int niswdev; /* number of interleaved swap devices */
+int niswap; /* size of interleaved swap area */
+#endif
+
+/*
+ * Set up swap devices.
+ * Initialize linked list of free swap
+ * headers. These do not actually point
+ * to buffers, but rather to pages that
+ * are being swapped in and out.
+ */
+void
+swapinit()
+{
+ register int i;
+ register struct buf *sp = swbuf;
+ register struct proc *p = &proc0; /* XXX */
+ struct swdevt *swp;
+ int error;
+
+ /*
+ * Count swap devices, and adjust total swap space available.
+ * Some of the space will not be countable until later (dynamically
+ * configurable devices) and some of the counted space will not be
+ * available until a swapon() system call is issued, both usually
+ * happen when the system goes multi-user.
+ *
+ * If using NFS for swap, swdevt[0] will already be bdevvp'd. XXX
+ */
+#ifdef SEQSWAP
+ nswdev = niswdev = 0;
+ nswap = niswap = 0;
+ /*
+ * All interleaved devices must come first
+ */
+ for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
+ if (swp->sw_flags & SW_SEQUENTIAL)
+ break;
+ niswdev++;
+ if (swp->sw_nblks > niswap)
+ niswap = swp->sw_nblks;
+ }
+ niswap = roundup(niswap, dmmax);
+ niswap *= niswdev;
+ if (swdevt[0].sw_vp == NULL &&
+ bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
+ panic("swapvp");
+ /*
+ * The remainder must be sequential
+ */
+ for ( ; swp->sw_dev != NODEV; swp++) {
+ if ((swp->sw_flags & SW_SEQUENTIAL) == 0)
+ panic("binit: mis-ordered swap devices");
+ nswdev++;
+ if (swp->sw_nblks > 0) {
+ if (swp->sw_nblks % dmmax)
+ swp->sw_nblks -= (swp->sw_nblks % dmmax);
+ nswap += swp->sw_nblks;
+ }
+ }
+ nswdev += niswdev;
+ if (nswdev == 0)
+ panic("swapinit");
+ nswap += niswap;
+#else
+ nswdev = 0;
+ nswap = 0;
+ for (swp = swdevt; swp->sw_dev != NODEV || swp->sw_vp != NULL; swp++) {
+ nswdev++;
+ if (swp->sw_nblks > nswap)
+ nswap = swp->sw_nblks;
+ }
+ if (nswdev == 0)
+ panic("swapinit");
+ if (nswdev > 1)
+ nswap = ((nswap + dmmax - 1) / dmmax) * dmmax;
+ nswap *= nswdev;
+ if (swdevt[0].sw_vp == NULL &&
+ bdevvp(swdevt[0].sw_dev, &swdevt[0].sw_vp))
+ panic("swapvp");
+#endif
+ if (nswap == 0)
+ printf("WARNING: no swap space found\n");
+ else if ((error = swfree(p, 0)) == ENXIO)
+ printf("WARNING: primary swap device not configured\n");
+ else if (error) {
+ printf("swfree errno %d\n", error); /* XXX */
+ panic("swapinit swfree 0");
+ }
+
+ /*
+ * Now set up swap buffer headers.
+ */
+ bswlist.b_actf = sp;
+ for (i = 0; i < nswbuf - 1; i++, sp++) {
+ sp->b_actf = sp + 1;
+ sp->b_rcred = sp->b_wcred = p->p_ucred;
+ sp->b_vnbufs.le_next = NOLIST;
+ }
+ sp->b_rcred = sp->b_wcred = p->p_ucred;
+ sp->b_vnbufs.le_next = NOLIST;
+ sp->b_actf = NULL;
+}
+
+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 (bp->b_blkno + sz > nswap) {
+ bp->b_error = EINVAL;
+ bp->b_flags |= B_ERROR;
+ biodone(bp);
+ return;
+ }
+ if (nswdev > 1) {
+#ifdef SEQSWAP
+ if (bp->b_blkno < niswap) {
+ if (niswdev > 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 % niswdev;
+ seg /= niswdev;
+ bp->b_blkno = seg*dmmax + off;
+ } else
+ index = 0;
+ } else {
+ register struct swdevt *swp;
+
+ bp->b_blkno -= niswap;
+ for (index = niswdev, swp = &swdevt[niswdev];
+ swp->sw_dev != NODEV;
+ swp++, index++) {
+ if (bp->b_blkno < swp->sw_nblks)
+ break;
+ bp->b_blkno -= swp->sw_nblks;
+ }
+ if (swp->sw_dev == NODEV ||
+ bp->b_blkno+sz > swp->sw_nblks) {
+ bp->b_error = swp->sw_dev == NODEV ?
+ ENODEV : EINVAL;
+ bp->b_flags |= B_ERROR;
+ biodone(bp);
+ return;
+ }
+ }
+#else
+ 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;
+#endif
+ } else
+ index = 0;
+ sp = &swdevt[index];
+ if (sp->sw_vp == NULL) {
+ bp->b_error = ENODEV;
+ bp->b_flags |= B_ERROR;
+ biodone(bp);
+ return;
+ }
+ if ((bp->b_dev = sp->sw_dev) == NODEV && sp->sw_vp->v_type != VREG)
+ panic("swstrategy");
+ VHOLD(sp->sw_vp);
+ if ((bp->b_flags & B_READ) == 0) {
+ if (vp = bp->b_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)
+ brelvp(bp);
+ bp->b_vp = sp->sw_vp;
+ VOP_STRATEGY(bp);
+}
+
+int
+swread(dev, uio)
+ dev_t dev;
+ struct uio *uio;
+{
+
+ return (physio(swstrategy, NULL, dev, B_READ, minphys, uio));
+}
+
+int
+swwrite(dev, uio)
+ dev_t dev;
+ struct uio *uio;
+{
+
+ return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio));
+}
+
+/*
+ * System call swapon(name) enables swapping on device name,
+ * which must be in the swdevsw. Return EBUSY
+ * if already swapping on this device.
+ */
+/* ARGSUSED */
+int
+sys_swapon(p, v, retval)
+ struct proc *p;
+ void *v;
+ register_t *retval;
+{
+ struct sys_swapon_args /* {
+ syscallarg(char *) name;
+ } */ *uap = v;
+ register struct vnode *vp;
+ register struct swdevt *sp;
+ dev_t dev;
+ int error;
+ struct nameidata nd;
+
+ if (error = suser(p->p_ucred, &p->p_acflag))
+ return (error);
+ NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, name), p);
+ if (error = namei(&nd))
+ return (error);
+ vp = nd.ni_vp;
+ if (vp->v_type != VBLK) {
+ vrele(vp);
+ return (ENOTBLK);
+ }
+ dev = (dev_t)vp->v_rdev;
+ if (major(dev) >= nblkdev) {
+ vrele(vp);
+ return (ENXIO);
+ }
+ for (sp = &swdevt[0]; sp->sw_dev != NODEV; sp++) {
+ if (sp->sw_dev == dev) {
+ if (sp->sw_flags & SW_FREED) {
+ vrele(vp);
+ return (EBUSY);
+ }
+ sp->sw_vp = vp;
+ if (error = swfree(p, sp - swdevt)) {
+ vrele(vp);
+ return (error);
+ }
+ return (0);
+ }
+#ifdef SEQSWAP
+ /*
+ * If we have reached a non-freed sequential device without
+ * finding what we are looking for, it is an error.
+ * That is because all interleaved devices must come first
+ * and sequential devices must be freed in order.
+ */
+ if ((sp->sw_flags & (SW_SEQUENTIAL|SW_FREED)) == SW_SEQUENTIAL)
+ break;
+#endif
+ }
+ vrele(vp);
+ return (EINVAL);
+}
+
+/*
+ * 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
+swfree(p, index)
+ struct proc *p;
+ int index;
+{
+ register struct swdevt *sp;
+ register swblk_t vsbase;
+ register long blk;
+ struct vnode *vp;
+ register swblk_t dvbase;
+ register int nblks;
+ int error;
+
+ sp = &swdevt[index];
+ vp = sp->sw_vp;
+ /* If root on swap, then the skip open/close operations. */
+ if (vp != rootvp) {
+ if (error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p))
+ return (error);
+ }
+ sp->sw_flags |= SW_FREED;
+ nblks = sp->sw_nblks;
+ /*
+ * Some devices may not exist til after boot time.
+ * If so, their nblk count will be 0.
+ */
+ if (nblks <= 0) {
+ int perdev;
+ dev_t dev = sp->sw_dev;
+
+ if (bdevsw[major(dev)].d_psize == 0 ||
+ (nblks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) {
+ if (vp != rootvp)
+ (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
+ sp->sw_flags &= ~SW_FREED;
+ return (ENXIO);
+ }
+#ifdef SEQSWAP
+ if (index < niswdev) {
+ perdev = niswap / niswdev;
+ if (nblks > perdev)
+ nblks = perdev;
+ } else {
+ if (nblks % dmmax)
+ nblks -= (nblks % dmmax);
+ nswap += nblks;
+ }
+#else
+ perdev = nswap / nswdev;
+ if (nblks > perdev)
+ nblks = perdev;
+#endif
+ sp->sw_nblks = nblks;
+ }
+ if (nblks == 0) {
+ if (vp != rootvp)
+ (void) VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
+ sp->sw_flags &= ~SW_FREED;
+ return (0); /* XXX error? */
+ }
+#ifdef SEQSWAP
+ if (sp->sw_flags & SW_SEQUENTIAL) {
+ register struct swdevt *swp;
+
+ blk = niswap;
+ for (swp = &swdevt[niswdev]; swp != sp; swp++)
+ blk += swp->sw_nblks;
+ rmfree(swapmap, nblks, blk);
+ return (0);
+ }
+#endif
+ for (dvbase = 0; dvbase < nblks; dvbase += dmmax) {
+ blk = nblks - dvbase;
+#ifdef SEQSWAP
+ if ((vsbase = index*dmmax + dvbase*niswdev) >= niswap)
+ panic("swfree");
+#else
+ if ((vsbase = index*dmmax + dvbase*nswdev) >= nswap)
+ panic("swfree");
+#endif
+ if (blk > dmmax)
+ blk = dmmax;
+ if (vsbase == 0) {
+ /*
+ * First of all chunks... initialize the swapmap.
+ * Don't use the first cluster of the device
+ * in case it starts with a label or boot block.
+ */
+ rminit(swapmap, blk - ctod(CLSIZE),
+ vsbase + ctod(CLSIZE), "swap", nswapmap);
+ } else if (dvbase == 0) {
+ /*
+ * Don't use the first cluster of the device
+ * in case it starts with a label or boot block.
+ */
+ rmfree(swapmap, blk - ctod(CLSIZE),
+ vsbase + ctod(CLSIZE));
+ } else
+ rmfree(swapmap, blk, vsbase);
+ }
+
+ /*
+ * Preserve the mini-root if appropriate:
+ * Note: this requires !SEQSWAP && nswdev==1
+ *
+ * A mini-root gets copied into the front of the swap
+ * and we run over top of the swap area just long
+ * enough for us to do a mkfs and restor of the real
+ * root (sure beats rewriting standalone restor).
+ */
+ if (vp == rootvp) {
+ struct mount *mp;
+ struct statfs *sp;
+ long firstblk;
+ int rootblks;
+
+#ifdef MINIROOTSIZE
+ rootblks = MINIROOTSIZE;
+#else
+ /* Get size from root FS (mountroot did statfs) */
+ mp = rootvnode->v_mount;
+ sp = &mp->mnt_stat;
+ rootblks = sp->f_blocks * (sp->f_bsize / DEV_BSIZE);
+#endif
+ if (rootblks > nblks)
+ panic("swfree miniroot size");
+ /* First ctod(CLSIZE) blocks are not in the map. */
+ firstblk = rmalloc(swapmap, rootblks - ctod(CLSIZE));
+ if (firstblk != ctod(CLSIZE))
+ panic("swfree miniroot save");
+ printf("Preserved %d blocks of miniroot leaving %d pages of swap\n",
+ rootblks, dtoc(nblks - rootblks));
+ }
+
+ return (0);
+}
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