sunvnet: Return from vnet_napi_event() if no packets to read

vnet_event_napi() may be called as part of the NAPI ->poll,
to resume reading descriptor rings. When no data is available,
descriptor ring state (e.g., rcv_nxt) needs to be reset
carefully to stay in lock-step with ldc_read(). In the interest
of simplicity, the best way to do this is to return from
vnet_event_napi() when there are no more packets to read.
The next trip through ldc_rx will correctly set up the dring state.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: David Stevens <david.stevens@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index 2688b19a6e63..5c5fb59adf76 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -691,7 +691,6 @@ ldc_ctrl:
                         pkt->end_idx = -1;
                         goto napi_resume;
                 }
-ldc_read:
                 err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
                 if (unlikely(err < 0)) {
                         if (err == -ECONNRESET)
@@ -722,8 +721,8 @@ napi_resume:
                                 err = vnet_rx(port, &msgbuf, &npkts, budget);
                                 if (npkts >= budget)
                                         break;
-                                if (npkts == 0 && err != -ECONNRESET)
-                                        goto ldc_read;
+                                if (npkts == 0)
+                                        break;
                         } else if (msgbuf.tag.stype == VIO_SUBTYPE_ACK) {
                                 err = vnet_ack(port, &msgbuf);
                                 if (err > 0)