- Avoid overflowing the swap size counters in human-readable mode

by introducing the new CONVERT_BLOCKS macro which operates on
  sizes already converted to number of blocks.  With this macro
  it is not longer needed to perform needless multiplication by
  blocksize just to divide on it later in CONVERT macro.

Approved by:	re (kib)
MFC after:	1 week

usr.sbin/pstat/pstat.c

@@ -460,6 +460,7 @@ getfiles(struct xfile **abuf, size_t *alen)
  */
 
 #define CONVERT(v)	((int64_t)(v) * pagesize / blocksize)
+#define CONVERT_BLOCKS(v)	((int64_t)(v) * pagesize)
 static struct kvm_swap swtot;
 static int nswdev;
 
@@ -492,10 +493,10 @@ print_swap_line(const char *swdevname, intmax_t nblks, intmax_t bused,
 	printf("%-15s %*jd ", swdevname, hlen, CONVERT(nblks));
 	if (humanflag) {
 		humanize_number(usedbuf, sizeof(usedbuf),
-		    CONVERT(blocksize * bused), "",
+		    CONVERT_BLOCKS(bused), "",
 		    HN_AUTOSCALE, HN_B | HN_NOSPACE | HN_DECIMAL);
 		humanize_number(availbuf, sizeof(availbuf),
-		    CONVERT(blocksize * bavail), "",
+		    CONVERT_BLOCKS(bavail), "",
 		    HN_AUTOSCALE, HN_B | HN_NOSPACE | HN_DECIMAL);
 		printf("%8s %8s %5.0f%%\n", usedbuf, availbuf, bpercent);
 	} else {