On Thu, 8 Aug 2019 12:52:11 -0700, Y Song wrote: > > Ah ok. In this scenario if driver has a native xdp support we would be > > invoking > > its ndo_bpf even if there's no prog currently attached and it wouldn't > > return > > error value. > > > > Looking at dev_xdp_uninstall, setting driver's prog to NULL is being done > > only > > when prog is attached. Maybe we should consider querying the driver in > > dev_change_xdp_fd regardless of passed fd value? E.g. don't query only when > > prog >= 0. > > > > I don't recall whether this was brought up previously. > > Thanks for explanation. I think return an error is better in > such error cases. Otherwise, people mistakenly write wrong > device name and they may think xdp is detached and it is > actually not. > > But this probably should not prevent > this patch as it is more like a kernel issue.
Agreed, we'd probably need a flag here, similar to IF_NOEXIST to keep backward compat.
