TI DaVinci EMAC: Fix asymmetric handling of packets in NAPI Poll function.

The current implementation of NAPI poll function in the driver does not service
Rx packets, error condition even if a single Tx packet gets serviced in
the napi poll call. This behavior severely affects performance for specific use
cases. This patch modifies the poll function implementation to service tx/rx
packets in an identical manner.

Signed-off-by: Sriramakrishnan <srk@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 13 deletions

diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
index 28633761be21..2ebf1a1dd1e1 100644
--- a/drivers/net/davinci_emac.c
+++ b/drivers/net/davinci_emac.c
@@ -2266,7 +2266,7 @@ static int emac_poll(struct napi_struct *napi, int budget)
         struct net_device *ndev = priv->ndev;
         struct device *emac_dev = &ndev->dev;
         u32 status = 0;
-        u32 num_pkts = 0;
+        u32 num_tx_pkts = 0, num_rx_pkts = 0;
 
         /* Check interrupt vectors and call packet processing */
         status = emac_read(EMAC_MACINVECTOR);
@@ -2277,27 +2277,19 @@ static int emac_poll(struct napi_struct *napi, int budget)
                 mask = EMAC_DM646X_MAC_IN_VECTOR_TX_INT_VEC;
 
         if (status & mask) {
-                num_pkts = emac_tx_bdproc(priv, EMAC_DEF_TX_CH,
+                num_tx_pkts = emac_tx_bdproc(priv, EMAC_DEF_TX_CH,
                                           EMAC_DEF_TX_MAX_SERVICE);
         } /* TX processing */
 
-        if (num_pkts)
-                return budget;
-
         mask = EMAC_DM644X_MAC_IN_VECTOR_RX_INT_VEC;
 
         if (priv->version == EMAC_VERSION_2)
                 mask = EMAC_DM646X_MAC_IN_VECTOR_RX_INT_VEC;
 
         if (status & mask) {
-                num_pkts = emac_rx_bdproc(priv, EMAC_DEF_RX_CH, budget);
+                num_rx_pkts = emac_rx_bdproc(priv, EMAC_DEF_RX_CH, budget);
         } /* RX processing */
 
-        if (num_pkts < budget) {
-                napi_complete(napi);
-                emac_int_enable(priv);
-        }
-
         mask = EMAC_DM644X_MAC_IN_VECTOR_HOST_INT;
         if (priv->version == EMAC_VERSION_2)
                 mask = EMAC_DM646X_MAC_IN_VECTOR_HOST_INT;
@@ -2328,9 +2320,12 @@ static int emac_poll(struct napi_struct *napi, int budget)
                                 dev_err(emac_dev, "RX Host error %s on ch=%d\n",
                                         &emac_rxhost_errcodes[cause][0], ch);
                 }
-        } /* Host error processing */
+        } else if (num_rx_pkts < budget) {
+                napi_complete(napi);
+                emac_int_enable(priv);
+        }
 
-        return num_pkts;
+        return num_rx_pkts;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER