ixgbe: Prevent unsupported configurations with XDP

These changes address comments by Jakub Kicinski on
commit 38b7e7f8 ("ixgbe: Do not allow LRO or MTU change with XDP").

Change the MTU check with XDP to allow any supported value and only
reject those outside of the range as opposed to rejecting any change
when XDP is active. In situations where MTU size is not supported,
return -EINVAL instead of -EPERM.

Add checks when enabling SRIOV, DCB, or adding L2FW offloaded device
as they are not supported with XDP.

CC: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -6620,8 +6620,18 @@ static int ixgbe_change_mtu(struct net_device *netdev, int new_mtu)
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 
 	if (adapter->xdp_prog) {
-		e_warn(probe, "MTU cannot be changed while XDP program is loaded\n");
-		return -EPERM;
+		int new_frame_size = new_mtu + ETH_HLEN + ETH_FCS_LEN +
+				     VLAN_HLEN;
+		int i;
+
+		for (i = 0; i < adapter->num_rx_queues; i++) {
+			struct ixgbe_ring *ring = adapter->rx_ring[i];
+
+			if (new_frame_size > ixgbe_rx_bufsz(ring)) {
+				e_warn(probe, "Requested MTU size is not supported with XDP\n");
+				return -EINVAL;
+			}
+		}
 	}
 
 	/*
@@ -8983,6 +8993,15 @@ int ixgbe_setup_tc(struct net_device *dev, u8 tc)
 
 #ifdef CONFIG_IXGBE_DCB
 	if (tc) {
+		if (adapter->xdp_prog) {
+			e_warn(probe, "DCB is not supported with XDP\n");
+
+			ixgbe_init_interrupt_scheme(adapter);
+			if (netif_running(dev))
+				ixgbe_open(dev);
+			return -EINVAL;
+		}
+
 		netdev_set_num_tc(dev, tc);
 		ixgbe_set_prio_tc_map(adapter);
 
@@ -9934,6 +9953,11 @@ static void *ixgbe_fwd_add(struct net_device *pdev, struct net_device *vdev)
 	int tcs = adapter->hw_tcs ? : 1;
 	int pool, err;
 
+	if (adapter->xdp_prog) {
+		e_warn(probe, "L2FW offload is not supported with XDP\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	/* The hardware supported by ixgbe only filters on the destination MAC
 	 * address. In order to avoid issues we only support offloading modes
 	 * where the hardware can actually provide the functionality.

drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c

@@ -53,6 +53,11 @@ static int __ixgbe_enable_sriov(struct ixgbe_adapter *adapter,
 	struct ixgbe_hw *hw = &adapter->hw;
 	int i;
 
+	if (adapter->xdp_prog) {
+		e_warn(probe, "SRIOV is not supported with XDP\n");
+		return -EINVAL;
+	}
+
 	/* Enable VMDq flag so device will be set in VM mode */
 	adapter->flags |= IXGBE_FLAG_SRIOV_ENABLED |
 			  IXGBE_FLAG_VMDQ_ENABLED;