3 files changed, 64 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index 425f86432f90..2262bf715b56 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -652,6 +652,7 @@ extern void ixgbe_atr_compute_perfect_hash_82599(union ixgbe_atr_input *input,
 						 union ixgbe_atr_input *mask);
 extern void ixgbe_set_rx_mode(struct net_device *netdev);
 #ifdef CONFIG_IXGBE_DCB
+extern void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter);
 extern int ixgbe_setup_tc(struct net_device *dev, u8 tc);
 #endif
 extern void ixgbe_tx_ctxtdesc(struct ixgbe_ring *, u32, u32, u32, u32);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c
index 7f2fa6992775..5164a21b13ca 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c
@@ -395,6 +395,9 @@ static u8 ixgbe_dcbnl_set_all(struct net_device *netdev)
 		} else {
 			hw->mac.ops.fc_enable(hw);
 		}
+
+		ixgbe_set_rx_drop_en(adapter);
+
 		ret = DCB_HW_CHG;
 	}
 
@@ -641,6 +644,8 @@ static int ixgbe_dcbnl_ieee_setpfc(struct net_device *dev,
 	else
 		err = hw->mac.ops.fc_enable(hw);
 
+	ixgbe_set_rx_drop_en(adapter);
+
 	return err;
 }
 
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 0915e77cf375..1693ec3d4046 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2771,6 +2771,61 @@ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter)
 		ixgbe_configure_tx_ring(adapter, adapter->tx_ring[i]);
 }
 
+static void ixgbe_enable_rx_drop(struct ixgbe_adapter *adapter,
+				 struct ixgbe_ring *ring)
+{
+	struct ixgbe_hw *hw = &adapter->hw;
+	u8 reg_idx = ring->reg_idx;
+	u32 srrctl = IXGBE_READ_REG(hw, IXGBE_SRRCTL(reg_idx));
+
+	srrctl |= IXGBE_SRRCTL_DROP_EN;
+
+	IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl);
+}
+
+static void ixgbe_disable_rx_drop(struct ixgbe_adapter *adapter,
+				  struct ixgbe_ring *ring)
+{
+	struct ixgbe_hw *hw = &adapter->hw;
+	u8 reg_idx = ring->reg_idx;
+	u32 srrctl = IXGBE_READ_REG(hw, IXGBE_SRRCTL(reg_idx));
+
+	srrctl &= ~IXGBE_SRRCTL_DROP_EN;
+
+	IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl);
+}
+
+#ifdef CONFIG_IXGBE_DCB
+void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter)
+#else
+static void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter)
+#endif
+{
+	int i;
+	bool pfc_en = adapter->dcb_cfg.pfc_mode_enable;
+
+	if (adapter->ixgbe_ieee_pfc)
+		pfc_en |= !!(adapter->ixgbe_ieee_pfc->pfc_en);
+
+	/*
+	 * We should set the drop enable bit if:
+	 *  SR-IOV is enabled
+	 *   or
+	 *  Number of Rx queues > 1 and flow control is disabled
+	 *
+	 *  This allows us to avoid head of line blocking for security
+	 *  and performance reasons.
+	 */
+	if (adapter->num_vfs || (adapter->num_rx_queues > 1 &&
+	    !(adapter->hw.fc.current_mode & ixgbe_fc_tx_pause) && !pfc_en)) {
+		for (i = 0; i < adapter->num_rx_queues; i++)
+			ixgbe_enable_rx_drop(adapter, adapter->rx_ring[i]);
+	} else {
+		for (i = 0; i < adapter->num_rx_queues; i++)
+			ixgbe_disable_rx_drop(adapter, adapter->rx_ring[i]);
+	}
+}
+
 #define IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT 2
 
 static void ixgbe_configure_srrctl(struct ixgbe_adapter *adapter,
@@ -5276,8 +5331,10 @@ static void ixgbe_watchdog_update_link(struct ixgbe_adapter *adapter)
 	if (adapter->ixgbe_ieee_pfc)
 		pfc_en |= !!(adapter->ixgbe_ieee_pfc->pfc_en);
 
-	if (link_up && !((adapter->flags & IXGBE_FLAG_DCB_ENABLED) && pfc_en))
+	if (link_up && !((adapter->flags & IXGBE_FLAG_DCB_ENABLED) && pfc_en)) {
 		hw->mac.ops.fc_enable(hw);
+		ixgbe_set_rx_drop_en(adapter);
+	}
 
 	if (link_up ||
 	    time_after(jiffies, (adapter->link_check_timeout +