On Tue, 29 Jan 2019 09:00:00 +0100 Jesper Dangaard Brouer <bro...@redhat.com> wrote:
> On Mon, 28 Jan 2019 20:16:11 +0100 > Maciej Fijalkowski <maciejromanfijalkow...@gmail.com> wrote: > > > From: Maciej Fijalkowski <maciej.fijalkow...@intel.com> > > > > Make xdp samples consistent with iproute2 behavior and set the > > XDP_FLAGS_UPDATE_IF_NOEXIST by default when setting the xdp program on > > interface. Provide an option for user to force the program loading, > > which as a result will not include the mentioned flag in > > bpf_set_link_xdp_fd call. > > I like the idea, but what is the error message users get after this > change? $ sudo ./xdp1 mlx5p1 & [1] 9768 $ sudo ./xdp1 mlx5p1 link set xdp fd failed This error message is a little too generic to be a good user experience. The kernel (in dev_change_xdp_fd) will return errno -EBUSY (-16), but we don't use or report the return value in these sample programs. If my QA see this error message, I will still get an error report bugzilla that I need to spend time on investigating. Can we please improve this error message? If you are really cool you get inspired by (or use) libbpf_strerror() code avail in tools/lib/bpf/libbpf_errno.c. Default strerror(EBUSY) will return "Device or resource busy", but maybe we can do slightly better and report something more meaningful for this XDP context. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
