fm10k: use different name than FM10K_VLAN_CLEAR for override bit

Use a new #define FM10K_VLAN_OVERRIDE even though we're using the exact
same bit. The reason for this is clarity in the code, otherwise you can
read FM10K_VLAN_CLEAR and think it should be removed. Also add a comment
explaining why the FM10K_VLAN_OVERRIDE bit is set.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/fm10k/fm10k_pf.c

@@ -864,9 +864,13 @@ static s32 fm10k_iov_assign_default_mac_vlan_pf(struct fm10k_hw *hw,
 	fm10k_write_reg(hw, FM10K_TQMAP(qmap_idx), 0);
 	fm10k_write_reg(hw, FM10K_TXDCTL(vf_q_idx), 0);
 
-	/* determine correct default VLAN ID */
+	/* Determine correct default VLAN ID. The FM10K_VLAN_OVERRIDE bit is
+	 * used here to indicate to the VF that it will not have privilege to
+	 * write VLAN_TABLE. All policy is enforced on the PF but this allows
+	 * the VF to correctly report errors to userspace rqeuests.
+	 */
 	if (vf_info->pf_vid)
-		vf_vid = vf_info->pf_vid | FM10K_VLAN_CLEAR;
+		vf_vid = vf_info->pf_vid | FM10K_VLAN_OVERRIDE;
 	else
 		vf_vid = vf_info->sw_vid;
 

drivers/net/ethernet/intel/fm10k/fm10k_type.h

@@ -350,6 +350,7 @@ struct fm10k_hw;
 #define FM10K_VLAN_TABLE_VSI_MAX		64
 #define FM10K_VLAN_LENGTH_SHIFT			16
 #define FM10K_VLAN_CLEAR			BIT(15)
+#define FM10K_VLAN_OVERRIDE			FM10K_VLAN_CLEAR
 #define FM10K_VLAN_ALL \
 	((FM10K_VLAN_TABLE_VID_MAX - 1) << FM10K_VLAN_LENGTH_SHIFT)
 

drivers/net/ethernet/intel/fm10k/fm10k_vf.c

@@ -228,7 +228,7 @@ s32 fm10k_msg_mac_vlan_vf(struct fm10k_hw *hw, u32 **results,
 
 	ether_addr_copy(hw->mac.perm_addr, perm_addr);
 	hw->mac.default_vid = vid & (FM10K_VLAN_TABLE_VID_MAX - 1);
-	hw->mac.vlan_override = !!(vid & FM10K_VLAN_CLEAR);
+	hw->mac.vlan_override = !!(vid & FM10K_VLAN_OVERRIDE);
 
 	return 0;
 }