[RFC 3/6] i40e: use extack for bpf errors

[Stephen Hemminger <stephen@networkplumber.org>]

From: Stephen Hemminger <stephen@networkplumber.org>

If ndo_bpf fails fill in error string with reason.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index da62218eb70a..3de1f2590ca0 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -11831,7 +11831,8 @@ static netdev_features_t i40e_features_check(struct sk_buff *skb,
  * @prog: XDP program
  **/
 static int i40e_xdp_setup(struct i40e_vsi *vsi,
-			  struct bpf_prog *prog)
+			  struct bpf_prog *prog,
+			  struct netlink_ext_ack *extack)
 {
 	int frame_size = vsi->netdev->mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
 	struct i40e_pf *pf = vsi->back;
@@ -11840,8 +11841,10 @@ static int i40e_xdp_setup(struct i40e_vsi *vsi,
 	int i;
 
 	/* Don't allow frames that span over multiple buffers */
-	if (frame_size > vsi->rx_buf_len)
+	if (frame_size > vsi->rx_buf_len) {
+		NL_SET_ERR_MSG(extack, "XDP does not support multiple buffers");
 		return -EINVAL;
+	}
 
 	if (!i40e_enabled_xdp_vsi(vsi) && !prog)
 		return 0;
@@ -12140,12 +12143,14 @@ static int i40e_xdp(struct net_device *dev,
 	struct i40e_netdev_priv *np = netdev_priv(dev);
 	struct i40e_vsi *vsi = np->vsi;
 
-	if (vsi->type != I40E_VSI_MAIN)
+	if (vsi->type != I40E_VSI_MAIN) {
+		NL_SET_ERR_MSG(xdp->extack, "XDP not allowed on VF");
 		return -EINVAL;
+	}
 
 	switch (xdp->command) {
 	case XDP_SETUP_PROG:
-		return i40e_xdp_setup(vsi, xdp->prog);
+		return i40e_xdp_setup(vsi, xdp->prog, xdp->extack);
 	case XDP_QUERY_PROG:
 		xdp->prog_id = vsi->xdp_prog ? vsi->xdp_prog->aux->id : 0;
 		return 0;
@@ -12153,6 +12158,7 @@ static int i40e_xdp(struct net_device *dev,
 		return i40e_xsk_umem_setup(vsi, xdp->xsk.umem,
 					   xdp->xsk.queue_id);
 	default:
+		NL_SET_ERR_MSG(xdp->extack, "Unknown XDP command");
 		return -EINVAL;
 	}
 }
-- 
2.17.1