[Qemu-devel] [PATCH] do not send packet to nic if the packet will be dropped by nic

[Wen Congyang <wency@cn.fujitsu.com>]

If !s->clock_enabled or !rtl8139_receiver_enabled(s), it means that
the nic will drop all packets from host. So qemu will keep getting
packets from host and wasting CPU on dropping packets. This seems
worse than packets that should be dropped but aren't.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>

---
 hw/rtl8139.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index 2f8db58..9084678 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -810,9 +810,9 @@ static int rtl8139_can_receive(VLANClientState *nc)
 
     /* Receive (drop) packets if card is disabled.  */
     if (!s->clock_enabled)
-      return 1;
+      return 0;
     if (!rtl8139_receiver_enabled(s))
-      return 1;
+      return 0;
 
     if (rtl8139_cp_receiver_enabled(s)) {
         /* ??? Flow control not implemented in c+ mode.
-- 1.7.1