[src/trunk]: src/sys/rump/net/lib/libvirtif work around tap bug: if /dev/tap<...

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

details:   https://anonhg.NetBSD.org/src/rev/dcf7a2a98231
branches:  trunk
changeset: 747463:dcf7a2a98231
user:      pooka <pooka%NetBSD.org@localhost>
date:      Wed Sep 16 13:29:42 2009 +0000

description:
work around tap bug: if /dev/tap<n> was previously non-blocking, newly
opened fd's will also be non-blocking.
(yeayea, i'll fix the kernel some day, but I don't want to reboot
my host OS now)

diffstat:

 sys/rump/net/lib/libvirtif/if_virt.c |  20 ++++++++++++++++++--
 1 files changed, 18 insertions(+), 2 deletions(-)

diffs (51 lines):

diff -r bde8d95a4140 -r dcf7a2a98231 sys/rump/net/lib/libvirtif/if_virt.c
--- a/sys/rump/net/lib/libvirtif/if_virt.c      Wed Sep 16 13:05:07 2009 +0000
+++ b/sys/rump/net/lib/libvirtif/if_virt.c      Wed Sep 16 13:29:42 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_virt.c,v 1.10 2009/05/27 23:41:20 pooka Exp $       */
+/*     $NetBSD: if_virt.c,v 1.11 2009/09/16 13:29:42 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 1.10 2009/05/27 23:41:20 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_virt.c,v 1.11 2009/09/16 13:29:42 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/condvar.h>
@@ -34,6 +34,7 @@
 #include <sys/kmem.h>
 #include <sys/kthread.h>
 #include <sys/mutex.h>
+#include <sys/poll.h>
 #include <sys/sockio.h>
 #include <sys/socketvar.h>
 
@@ -207,9 +208,24 @@
                m = m_gethdr(M_WAIT, MT_DATA);
                MEXTMALLOC(m, plen, M_WAIT);
 
+ again:
                n = rumpuser_read(sc->sc_tapfd, mtod(m, void *), plen, &error);
                KASSERT(n < ETHER_MAX_LEN_JUMBO);
                if (n <= 0) {
+                       /*
+                        * work around tap bug: /dev/tap is opened in
+                        * non-blocking mode if it previously was
+                        * non-blocking.
+                        */
+                       if (n == -1 && error == EAGAIN) {
+                               struct pollfd pfd;
+
+                               pfd.fd = sc->sc_tapfd;
+                               pfd.events = POLLIN;
+
+                               rumpuser_poll(&pfd, 1, INFTIM, &error);
+                               goto again;
+                       }
                        m_freem(m);
                        break;
                }