[src/trunk]: src/sys/rump/net/lib/libvirtif * improve diagnostic print

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

details:   https://anonhg.NetBSD.org/src/rev/79384010c010
branches:  trunk
changeset: 757011:79384010c010
user:      pooka <pooka%NetBSD.org@localhost>
date:      Tue Aug 10 18:06:10 2010 +0000

description:
* improve diagnostic print
* deal with a tap quirk when it returns 0 bytes

diffstat:

 sys/rump/net/lib/libvirtif/if_virt.c |  15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diffs (53 lines):

diff -r 9d25cdcff413 -r 79384010c010 sys/rump/net/lib/libvirtif/if_virt.c
--- a/sys/rump/net/lib/libvirtif/if_virt.c      Tue Aug 10 17:53:08 2010 +0000
+++ b/sys/rump/net/lib/libvirtif/if_virt.c      Tue Aug 10 18:06:10 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_virt.c,v 1.18 2010/04/05 16:35:30 joerg Exp $       */
+/*     $NetBSD: if_virt.c,v 1.19 2010/08/10 18:06:10 pooka Exp $       */
 
 /*
  * Copyright (c) 2008 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_virt.c,v 1.18 2010/04/05 16:35:30 joerg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_virt.c,v 1.19 2010/08/10 18:06:10 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/condvar.h>
@@ -110,7 +110,8 @@
        snprintf(tapdev, sizeof(tapdev), "/dev/tap%d", num);
        fd = rumpuser_open(tapdev, O_RDWR, &error);
        if (fd == -1) {
-               printf("virtif_create: can't open /dev/tap %d\n", error);
+               printf("virtif_create: can't open /dev/tap%d: %d\n",
+                   num, error);
                return error;
        }
        KASSERT(num < 0x100);
@@ -212,7 +213,7 @@
  again:
                n = rumpuser_read(sc->sc_tapfd, mtod(m, void *), plen, &error);
                KASSERT(n < ETHER_MAX_LEN_JUMBO);
-               if (n <= 0) {
+               if (__predict_false(n < 0)) {
                        /*
                         * work around tap bug: /dev/tap is opened in
                         * non-blocking mode if it previously was
@@ -227,9 +228,15 @@
                                rumpuser_poll(&pfd, 1, INFTIM, &error);
                                goto again;
                        }
+
                        m_freem(m);
                        break;
                }
+
+               /* tap sometimes returns EOF.  don't sweat it and plow on */
+               if (__predict_false(n == 0))
+                       goto again;
+
                m->m_len = m->m_pkthdr.len = n;
                m->m_pkthdr.rcvif = ifp;
                bpf_mtap(ifp, m);