[src/trunk]: src/share/man/man9 Fix example code and emphasize it doesn't han...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c20950f41a66
branches:  trunk
changeset: 337029:c20950f41a66
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Mar 30 13:58:03 2015 +0000

description:
Fix example code and emphasize it doesn't handle holes.

diffstat:

 share/man/man9/bufferio.9 |  8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diffs (29 lines):

diff -r 48cabf7b9323 -r c20950f41a66 share/man/man9/bufferio.9
--- a/share/man/man9/bufferio.9 Mon Mar 30 13:51:42 2015 +0000
+++ b/share/man/man9/bufferio.9 Mon Mar 30 13:58:03 2015 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: bufferio.9,v 1.12 2015/03/30 13:40:01 riastradh Exp $
+.\"    $NetBSD: bufferio.9,v 1.13 2015/03/30 13:58:03 riastradh Exp $
 .\"
 .\" Copyright (c) 2015 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -235,7 +235,8 @@
 mbp->b_resid = mbp->b_bcount = datalen;
 mbp->b_flags = B_WRITE;
 
-KASSERT(i < nsegs);
+KASSERT(0 < nsegs);
+KASSERT(datalen == nsegs*segsz);
 for (i = 0; i < nsegs; i++) {
        struct vnode *devvp;
        daddr_t blkno;
@@ -246,7 +247,8 @@
        if (error == 0 && nbn == -1)
                error = EIO;
        if (error) {
-               skipped += segsz;
+               /* Give up early, don't try to handle holes.  */
+               skipped += datalen - i*segsz;
                break;
        }