sunvnet: add memory barrier before check for tx enable

In order to allow the underlying LDC and outstanding memory operations
to potentially catch up with the driver's Tx requests, add a memory
barrier before checking again for available tx descriptors.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c
index 0f940f0..623363b 100644 (file)
--- a/drivers/net/ethernet/sun/sunvnet_common.c
+++ b/drivers/net/ethernet/sun/sunvnet_common.c
@@ -1427,6 +1427,7 @@ ldc_start_done:
        dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
        if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
                netif_tx_stop_queue(txq);
+               smp_rmb();
                if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
                        netif_tx_wake_queue(txq);
        }