From: Brenden Blanco <bbla...@plumgrid.com>
Date: Mon, 11 Jul 2016 14:29:49 -0700
> + if (fd >= 0) {
> + prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
> + if (IS_ERR(prog))
> + return PTR_ERR(prog);
> + }
> +
> + xdp.command = XDP_SETUP_PROG;
> + xdp.prog = prog;
> + err = ops->ndo_xdp(dev, &xdp);
> + if (err < 0 && prog)
> + bpf_prog_put(prog);
I don't understand the reference counting on 'prog' here.
The enumeration documentation states that no matter what, the passed
in prog doesn't need to be mangaged by the ->ndo_xdp() method.
Therefore, if that is true, we must always put the 'prog' here if it
is non-NULL. Regardless of the 'err' value.
