net: ethernet: mtk_eth_soc: Reset prog ptr to old_prog in case of error in mtk_xdp_setup()

Reset eBPF program pointer to old_prog and do not decrease its ref-count
if mtk_open routine in mtk_xdp_setup() fails.

Fixes: 7c26c20 ("net: ethernet: mtk_eth_soc: add basic XDP support")
Suggested-by: Paolo Valerio <[email protected]>
Signed-off-by: Lorenzo Bianconi <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: LorenzoBianconi

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -3748,12 +3748,21 @@ static int mtk_xdp_setup(struct net_device *dev, struct bpf_prog *prog,
 		mtk_stop(dev);
 
 	old_prog = rcu_replace_pointer(eth->prog, prog, lockdep_rtnl_is_held());
+
+	if (netif_running(dev) && need_update) {
+		int err;
+
+		err = mtk_open(dev);
+		if (err) {
+			rcu_assign_pointer(eth->prog, old_prog);
+
+			return err;
+		}
+	}
+
 	if (old_prog)
 		bpf_prog_put(old_prog);
 
-	if (netif_running(dev) && need_update)
-		return mtk_open(dev);
-
 	return 0;
 }