[RFC 2/6] ixgbe: use extack for xdp errors

[Stephen Hemminger]

From: Stephen Hemminger <step...@networkplumber.org>

Give a reason for returning error for bpf setup.

Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 25 +++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index a4e7584a50cb..9a81123074ca 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -10224,18 +10224,23 @@ ixgbe_features_check(struct sk_buff *skb, struct 
net_device *dev,
        return features;
 }
 
-static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog)
+static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog,
+                          struct netlink_ext_ack *extack)
 {
        int i, frame_size = dev->mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
        struct ixgbe_adapter *adapter = netdev_priv(dev);
        struct bpf_prog *old_prog;
        bool need_reset;
 
-       if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
+       if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) {
+               NL_SET_ERR_MSG(extack, "XDP not support with SRIOV enabled");
                return -EINVAL;
+       }
 
-       if (adapter->flags & IXGBE_FLAG_DCB_ENABLED)
+       if (adapter->flags & IXGBE_FLAG_DCB_ENABLED) {
+               NL_SET_ERR_MSG(extack, "XDP not supported with DCB enabled");
                return -EINVAL;
+       }
 
        /* verify ixgbe ring attributes are sufficient for XDP */
        for (i = 0; i < adapter->num_rx_queues; i++) {
@@ -10244,12 +10249,17 @@ static int ixgbe_xdp_setup(struct net_device *dev, 
struct bpf_prog *prog)
                if (ring_is_rsc_enabled(ring))
                        return -EINVAL;
 
-               if (frame_size > ixgbe_rx_bufsz(ring))
+               if (frame_size > ixgbe_rx_bufsz(ring)) {
+                       NL_SET_ERR_MSG(extack,
+                                      "XDP does not support multiple buffers");
                        return -EINVAL;
+               }
        }
 
-       if (nr_cpu_ids > MAX_XDP_QUEUES)
+       if (nr_cpu_ids > MAX_XDP_QUEUES) {
+               NL_SET_ERR_MSG(extack, "number of cpus > MAX_XDP_QUEUES");
                return -ENOMEM;
+       }
 
        old_prog = xchg(&adapter->xdp_prog, prog);
        need_reset = (!!prog != !!old_prog);
@@ -10260,7 +10270,7 @@ static int ixgbe_xdp_setup(struct net_device *dev, 
struct bpf_prog *prog)
 
                if (err) {
                        rcu_assign_pointer(adapter->xdp_prog, old_prog);
-                       return -EINVAL;
+                       return err;
                }
        } else {
                for (i = 0; i < adapter->num_rx_queues; i++)
@@ -10288,7 +10298,7 @@ static int ixgbe_xdp(struct net_device *dev, struct 
netdev_bpf *xdp)
 
        switch (xdp->command) {
        case XDP_SETUP_PROG:
-               return ixgbe_xdp_setup(dev, xdp->prog);
+               return ixgbe_xdp_setup(dev, xdp->prog, xdp->extack);
        case XDP_QUERY_PROG:
                xdp->prog_id = adapter->xdp_prog ?
                        adapter->xdp_prog->aux->id : 0;
@@ -10298,6 +10308,7 @@ static int ixgbe_xdp(struct net_device *dev, struct 
netdev_bpf *xdp)
                                            xdp->xsk.queue_id);
 
        default:
+               NL_SET_ERR_MSG(xdp->extack, "Unknown XDP command");
                return -EINVAL;
        }
 }
-- 
2.17.1