rocker: don't queue receive pkts when port is disabled

Commit 6e99c63 ("net/socket: Drop net_socket_can_send") changed the
semantics around .can_receive for sockets to now require the device to
flush queued pkts when transitioning to a .can_receive=true state.  Rocker
device was not flushing the queue on .can_receive=true transition, so the
receiver was stuck.

But, turns out we really don't want any queuing at all on the port when the
port is disabled, otherwise when the port transitions to enabled, we'd
receive and forward stale pkts that really should have been dropped.  So,
let's remove .can_receive so avoid queuing and drop the pkt in .receive if
the port is disabled.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1435717553-36187-1-git-send-email-sfeldma@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/hw/net/rocker/rocker_fp.c b/hw/net/rocker/rocker_fp.c
index d8d934c396288bf901ba2ff8e797d265949417b3..c693ae5081397d566c88097ecd9fe76f22501fe5 100644 (file)
--- a/hw/net/rocker/rocker_fp.c
+++ b/hw/net/rocker/rocker_fp.c
@@ -125,18 +125,21 @@ int fp_port_eg(FpPort *port, const struct iovec *iov, int iovcnt)
     return ROCKER_OK;
 }
 
-static int fp_port_can_receive(NetClientState *nc)
-{
-    FpPort *port = qemu_get_nic_opaque(nc);
-
-    return port->enabled;
-}
-
 static ssize_t fp_port_receive_iov(NetClientState *nc, const struct iovec *iov,
                                    int iovcnt)
 {
     FpPort *port = qemu_get_nic_opaque(nc);
 
+    /* If the port is disabled, we want to drop this pkt
+     * now rather than queing it for later.  We don't want
+     * any stale pkts getting into the device when the port
+     * transitions to enabled.
+     */
+
+    if (!port->enabled) {
+        return -1;
+    }
+
     return world_ingress(port->world, port->pport, iov, iovcnt);
 }
 
@@ -165,7 +168,6 @@ static void fp_port_set_link_status(NetClientState *nc)
 static NetClientInfo fp_port_info = {
     .type = NET_CLIENT_OPTIONS_KIND_NIC,
     .size = sizeof(NICState),
-    .can_receive = fp_port_can_receive,
     .receive = fp_port_receive,
     .receive_iov = fp_port_receive_iov,
     .cleanup = fp_port_cleanup,