[PATCH AUTOSEL 4.14 29/35] net: thunderx: set xdp_prog to NULL if bpf_prog_add fails

Sasha Levin
2018-11-29T06:03:11Z

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

[ Upstream commit 6d0f60b0f8588fd4380ea5df9601e12fddd55ce2 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/cavium/thunder/nicvf_main.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 2237ef8e4344..f13256af8031 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -1691,6 +1691,7 @@ 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)) {
@@ -1724,8 +1725,12 @@ 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 */
@@ -1737,7 +1742,7 @@ 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_xdp *xdp)
--
2.17.1