l2tpv3: Drop l2tpv3_can_send

This callback is called by main loop before polling s->fd, if it returns
false, the fd will not be polled in this iteration.

This is redundant with checks inside read callback. After this patch,
the data will be copied from s->fd to s->msgvec when it arrives. If the
device can't receive, it will be queued to incoming_queue, and when the
device status changes, this queue will be flushed.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1433400324-7358-4-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

net/l2tpv3.c

@@ -133,14 +133,12 @@ typedef struct NetL2TPV3State {
 
 } NetL2TPV3State;
 
-static int l2tpv3_can_send(void *opaque);
 static void net_l2tpv3_send(void *opaque);
 static void l2tpv3_writable(void *opaque);
 
 static void l2tpv3_update_fd_handler(NetL2TPV3State *s)
 {
-    qemu_set_fd_handler2(s->fd,
-                         s->read_poll ? l2tpv3_can_send : NULL,
+    qemu_set_fd_handler2(s->fd, NULL,
                          s->read_poll ? net_l2tpv3_send     : NULL,
                          s->write_poll ? l2tpv3_writable : NULL,
                          s);
@@ -169,13 +167,6 @@ static void l2tpv3_writable(void *opaque)
     qemu_flush_queued_packets(&s->nc);
 }
 
-static int l2tpv3_can_send(void *opaque)
-{
-    NetL2TPV3State *s = opaque;
-
-    return qemu_can_send_packet(&s->nc);
-}
-
 static void l2tpv3_send_completed(NetClientState *nc, ssize_t len)
 {
     NetL2TPV3State *s = DO_UPCAST(NetL2TPV3State, nc, nc);