netdev-linux: Do not log a warning if the device is down.

In the userspace datapath we use tap devices as internal netdev.  The
datapath doesn't consider whether a device is up or down before sending
to it, and so far this hasn't been a problem.

Since Linux upstream commit 1bd4978a88ac("tun: honor IFF_UP in
tun_get_user()"), included in 4.4, writing to a tap device that is not
up sets errno to EIO.  This commit avoids printing a warning in this
case.

This fixes a failures in the system-userspace-testsuites.

Reported-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: Ben Pfaff <blp@ovn.org>

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index ef11d12..486910a 100644 (file)
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -1223,15 +1223,20 @@ netdev_linux_send(struct netdev *netdev_, int qid OVS_UNUSED,
         }
 
         if (retval < 0) {
-            /* The Linux AF_PACKET implementation never blocks waiting for room
-             * for packets, instead returning ENOBUFS.  Translate this into
-             * EAGAIN for the caller. */
-            error = errno == ENOBUFS ? EAGAIN : errno;
-            if (error == EINTR) {
-                /* continue without incrementing 'i', i.e. retry this packet */
+            if (errno == EINTR) {
+                /* The send was interrupted by a signal.  Retry the packet by
+                 * continuing without incrementing 'i'.*/
                 continue;
+            } else if (errno == EIO && is_tap_netdev(netdev_)) {
+                /* The Linux tap driver returns EIO if the device is not up.
+                 * From the OVS side this is not an error, so ignore it. */
+            } else {
+                /* The Linux AF_PACKET implementation never blocks waiting for
+                 * room for packets, instead returning ENOBUFS.  Translate this
+                 * into EAGAIN for the caller. */
+                error = errno == ENOBUFS ? EAGAIN : errno;
+                break;
             }
-            break;
         } else if (retval != size) {
             VLOG_WARN_RL(&rl, "sent partial Ethernet packet (%"PRIuSIZE" bytes"
                               " of %"PRIuSIZE") on %s", retval, size,