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.

1 files changed, 11 insertions, 17 deletions

diff --git a/sys/vm/vm_swap.c b/sys/vm/vm_swap.c
index 682d11a..d66fb01 100644
--- a/sys/vm/vm_swap.c
+++ b/sys/vm/vm_swap.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vm_swap.c	8.5 (Berkeley) 2/17/94
- * $Id: vm_swap.c,v 1.16 1995/05/12 03:54:59 phk Exp $
+ * $Id: vm_swap.c,v 1.17 1995/05/14 03:00:10 davidg Exp $
  */
 
 #include <sys/param.h>
@@ -58,7 +58,7 @@
 #endif
 static struct swdevt should_be_malloced[NSWAPDEV];
 struct swdevt *swdevt = should_be_malloced;
-int nswap;
+int nswap;			/* first block after the interleaved devs */
 int nswdev = NSWAPDEV;
 int vm_swap_size;
 int bswneeded;
@@ -73,12 +73,6 @@ swstrategy(bp)
 	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) {
 		off = bp->b_blkno % dmmax;
 		if (off + sz > dmmax) {
@@ -94,6 +88,12 @@ swstrategy(bp)
 	} 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) {
@@ -241,17 +241,11 @@ swaponvp(p, vp, dev, nblks)
 	sp->sw_nblks = nblks;
 
 	if (nblks * nswdev > nswap)
-		nswap = nblks * nswdev;
+		nswap = (nblks+1) * nswdev;
 
 	for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
-		blk = nblks - dvbase;
-
-		if ((vsbase = index * dmmax + dvbase * nswdev) >= nswap)
-			panic("swfree");
-		if (blk > dmmax)
-			blk = dmmax;
-		/* XXX -- we need to exclude the first cluster as above */
-		/* but for now, this will work fine... */
+		blk = min(nblks - dvbase,dmmax);
+		vsbase = index * dmmax + dvbase * nswdev;
 		rlist_free(&swaplist, vsbase, vsbase + blk - 1);
 		vm_swap_size += blk;
 	}