[netdrvr] sfc: Add TSO support

The SFC4000 controller does not have hardware support for TSO, and the
core GSO code incurs a high cost in allocating and freeing skbs.  This
TSO implementation uses lightweight packet header structures and is
substantially faster.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index ad541badbd98..b756840e2a16 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -272,6 +272,22 @@ static void efx_ethtool_get_stats(struct net_device *net_dev,
         }
 }
 
+static int efx_ethtool_set_tso(struct net_device *net_dev, u32 enable)
+{
+        int rc;
+
+        /* Our TSO requires TX checksumming, so force TX checksumming
+         * on when TSO is enabled.
+         */
+        if (enable) {
+                rc = efx_ethtool_set_tx_csum(net_dev, 1);
+                if (rc)
+                        return rc;
+        }
+
+        return ethtool_op_set_tso(net_dev, enable);
+}
+
 static int efx_ethtool_set_tx_csum(struct net_device *net_dev, u32 enable)
 {
         struct efx_nic *efx = net_dev->priv;
@@ -283,6 +299,15 @@ static int efx_ethtool_set_tx_csum(struct net_device *net_dev, u32 enable)
 
         efx_flush_queues(efx);
 
+        /* Our TSO requires TX checksumming, so disable TSO when
+         * checksumming is disabled
+         */
+        if (!enable) {
+                rc = efx_ethtool_set_tso(net_dev, 0);
+                if (rc)
+                        return rc;
+        }
+
         return 0;
 }
 
@@ -451,6 +476,8 @@ struct ethtool_ops efx_ethtool_ops = {
         .set_tx_csum            = efx_ethtool_set_tx_csum,
         .get_sg                 = ethtool_op_get_sg,
         .set_sg                 = ethtool_op_set_sg,
+        .get_tso                = ethtool_op_get_tso,
+        .set_tso                = efx_ethtool_set_tso,
         .get_flags              = ethtool_op_get_flags,
         .set_flags              = ethtool_op_set_flags,
         .get_strings            = efx_ethtool_get_strings,