ixgbe: Simplify definitions for regidx and bit in set_vfta

This patch simplifies the logic for setting the VFTA register by removing
the number of conditional checks needed.  Instead we just use some boolean
logic to generate vfta_delta, and if that is set then we xor the vfta by
that value and write it back.

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

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
index daec6ae..027c1ad 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
@@ -3050,13 +3050,9 @@ static s32 ixgbe_find_vlvf_slot(struct ixgbe_hw *hw, u32 vlan)
 s32 ixgbe_set_vfta_generic(struct ixgbe_hw *hw, u32 vlan, u32 vind,
                           bool vlan_on)
 {
-       s32 regindex;
-       u32 bitindex;
-       u32 vfta;
+       u32 regidx, vfta_delta, vfta;
        u32 bits;
        u32 vt;
-       u32 targetbit;
-       bool vfta_changed = false;
 
        if (vlan > 4095)
                return IXGBE_ERR_PARAM;
@@ -3073,22 +3069,16 @@ s32 ixgbe_set_vfta_generic(struct ixgbe_hw *hw, u32 vlan, u32 vind,
         *    bits[11-5]: which register
         *    bits[4-0]:  which bit in the register
         */
-       regindex = (vlan >> 5) & 0x7F;
-       bitindex = vlan & 0x1F;
-       targetbit = (1 << bitindex);
-       vfta = IXGBE_READ_REG(hw, IXGBE_VFTA(regindex));
-
-       if (vlan_on) {
-               if (!(vfta & targetbit)) {
-                       vfta |= targetbit;
-                       vfta_changed = true;
-               }
-       } else {
-               if ((vfta & targetbit)) {
-                       vfta &= ~targetbit;
-                       vfta_changed = true;
-               }
-       }
+       regidx = vlan / 32;
+       vfta_delta = 1 << (vlan % 32);
+       vfta = IXGBE_READ_REG(hw, IXGBE_VFTA(regidx));
+
+       /* vfta_delta represents the difference between the current value
+        * of vfta and the value we want in the register.  Since the diff
+        * is an XOR mask we can just update vfta using an XOR.
+        */
+       vfta_delta &= vlan_on ? ~vfta : vfta;
+       vfta ^= vfta_delta;
 
        /* Part 2
         * If VT Mode is set
@@ -3164,19 +3154,19 @@ s32 ixgbe_set_vfta_generic(struct ixgbe_hw *hw, u32 vlan, u32 vind,
                if (bits) {
                        IXGBE_WRITE_REG(hw, IXGBE_VLVF(vlvf_index),
                                        (IXGBE_VLVF_VIEN | vlan));
-                       if (!vlan_on) {
-                               /* someone wants to clear the vfta entry
-                                * but some pools/VFs are still using it.
-                                * Ignore it. */
-                               vfta_changed = false;
-                       }
+
+                       /* if someone wants to clear the vfta entry but
+                        * some pools/VFs are still using it.  Ignore it.
+                        */
+                       if (!vlan_on)
+                               vfta_delta = 0;
                } else {
                        IXGBE_WRITE_REG(hw, IXGBE_VLVF(vlvf_index), 0);
                }
        }
 
-       if (vfta_changed)
-               IXGBE_WRITE_REG(hw, IXGBE_VFTA(regindex), vfta);
+       if (vfta_delta)
+               IXGBE_WRITE_REG(hw, IXGBE_VFTA(regidx), vfta);
 
        return 0;
 }