net: thunderx: set xdp_prog to NULL if bpf_prog_add fails

Set xdp_prog pointer to NULL if bpf_prog_add fails since that routine
reports the error code instead of NULL in case of failure and xdp_prog
pointer value is used in the driver to verify if XDP is currently
enabled.
Moreover report the error code to userspace if nicvf_xdp_setup fails

Fixes: 05c773f52b96 ("net: thunderx: Add basic XDP support")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 768f584..88f8a8f 100644 (file)
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -1784,6 +1784,7 @@ static int nicvf_xdp_setup(struct nicvf *nic, struct bpf_prog *prog)
        bool if_up = netif_running(nic->netdev);
        struct bpf_prog *old_prog;
        bool bpf_attached = false;
+       int ret = 0;
 
        /* For now just support only the usual MTU sized frames */
        if (prog && (dev->mtu > 1500)) {
@@ -1817,8 +1818,12 @@ static int nicvf_xdp_setup(struct nicvf *nic, struct bpf_prog *prog)
        if (nic->xdp_prog) {
                /* Attach BPF program */
                nic->xdp_prog = bpf_prog_add(nic->xdp_prog, nic->rx_queues - 1);
-               if (!IS_ERR(nic->xdp_prog))
+               if (!IS_ERR(nic->xdp_prog)) {
                        bpf_attached = true;
+               } else {
+                       ret = PTR_ERR(nic->xdp_prog);
+                       nic->xdp_prog = NULL;
+               }
        }
 
        /* Calculate Tx queues needed for XDP and network stack */
@@ -1830,7 +1835,7 @@ static int nicvf_xdp_setup(struct nicvf *nic, struct bpf_prog *prog)
                netif_trans_update(nic->netdev);
        }
 
-       return 0;
+       return ret;
 }
 
 static int nicvf_xdp(struct net_device *netdev, struct netdev_bpf *xdp)