ixgbe: Fix handling of FDIR_HASH flag

This change makes it so that we can use the atr_sample_rate to determine if
we are capable of supporting ATR. The advantage to this approach is that it
allows us to now determine the setting of the IXGBE_FLAG_FDIR_HASH_CAPABLE
based on the queueing scheme, instead of the queueing scheme being based on
the flag.

Using this approach there are essentially 5 conditions that must be checked
prior to trying to enable ATR:
1.  Is SR-IOV disabled?
2.  Are the number of TCs <= 1?
3.  Is RSS queueing limit greater than 1?
4.  Is atr_sample_rate set?
5.  Is Flow Director perfect filtering disabled?

If any of these conditions are enabled they should disable ATR filtering.
Note that in the case of conditions 1 through 4 being met we will set
things up for ATR queueing, however if test 5 fails we will still leave the
queues allocated for use by perfect filters.  The reason for this is to
allow for us to switch back and forth between ntuple and ATR without
needing to reallocate the descriptor rings.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 32 insertions, 16 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 9c42679ad83e..7be35043b751 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2688,8 +2688,7 @@ void ixgbe_configure_tx_ring(struct ixgbe_adapter *adapter,
                    32;          /* PTHRESH = 32 */
 
         /* reinitialize flowdirector state */
-        if ((adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) &&
-            adapter->atr_sample_rate) {
+        if (adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) {
                 ring->atr_sample_rate = adapter->atr_sample_rate;
                 ring->atr_count = 0;
                 set_bit(__IXGBE_TX_FDIR_INIT_DONE, &ring->state);
@@ -4419,7 +4418,6 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
                 if (hw->device_id == IXGBE_DEV_ID_82599_T3_LOM)
                         adapter->flags2 |= IXGBE_FLAG2_TEMP_SENSOR_CAPABLE;
                 /* Flow Director hash filters enabled */
-                adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;
                 adapter->atr_sample_rate = 20;
                 adapter->ring_feature[RING_F_FDIR].limit =
                                                          IXGBE_MAX_FDIR_INDICES;
@@ -6726,7 +6724,6 @@ int ixgbe_setup_tc(struct net_device *dev, u8 tc)
                 ixgbe_set_prio_tc_map(adapter);
 
                 adapter->flags |= IXGBE_FLAG_DCB_ENABLED;
-                adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
 
                 if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
                         adapter->last_lfc_mode = adapter->hw.fc.requested_mode;
@@ -6739,7 +6736,6 @@ int ixgbe_setup_tc(struct net_device *dev, u8 tc)
                         adapter->hw.fc.requested_mode = adapter->last_lfc_mode;
 
                 adapter->flags &= ~IXGBE_FLAG_DCB_ENABLED;
-                adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;
 
                 adapter->temp_dcb_cfg.pfc_mode_enable = false;
                 adapter->dcb_cfg.pfc_mode_enable = false;
@@ -6808,20 +6804,40 @@ static int ixgbe_set_features(struct net_device *netdev,
          * Check if Flow Director n-tuple support was enabled or disabled.  If
          * the state changed, we need to reset.
          */
-        if (!(features & NETIF_F_NTUPLE)) {
-                if (adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE) {
-                        /* turn off Flow Director, set ATR and reset */
-                        if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) &&
-                            !(adapter->flags & IXGBE_FLAG_DCB_ENABLED))
-                                adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;
-                        need_reset = true;
-                }
-                adapter->flags &= ~IXGBE_FLAG_FDIR_PERFECT_CAPABLE;
-        } else if (!(adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE)) {
+        switch (features & NETIF_F_NTUPLE) {
+        case NETIF_F_NTUPLE:
                 /* turn off ATR, enable perfect filters and reset */
+                if (!(adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE))
+                        need_reset = true;
+
                 adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
                 adapter->flags |= IXGBE_FLAG_FDIR_PERFECT_CAPABLE;
-                need_reset = true;
+                break;
+        default:
+                /* turn off perfect filters, enable ATR and reset */
+                if (adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE)
+                        need_reset = true;
+
+                adapter->flags &= ~IXGBE_FLAG_FDIR_PERFECT_CAPABLE;
+
+                /* We cannot enable ATR if SR-IOV is enabled */
+                if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
+                        break;
+
+                /* We cannot enable ATR if we have 2 or more traffic classes */
+                if (netdev_get_num_tc(netdev) > 1)
+                        break;
+
+                /* We cannot enable ATR if RSS is disabled */
+                if (adapter->ring_feature[RING_F_RSS].limit <= 1)
+                        break;
+
+                /* A sample rate of 0 indicates ATR disabled */
+                if (!adapter->atr_sample_rate)
+                        break;
+
+                adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;
+                break;
         }
 
         if (features & NETIF_F_HW_VLAN_RX)