On 11/11/2019 17:38, Arthur Fabre wrote: > On Mon, Nov 11, 2019 at 5:27 PM Edward Cree <ecree@xxxxxxxxxxxxxx> wrote: >> >> On 11/11/2019 10:51, Arthur Fabre wrote: >>> diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c >>> index a7d9841105d8..5bfe1f6112a1 100644 >>> --- a/drivers/net/ethernet/sfc/rx.c >>> +++ b/drivers/net/ethernet/sfc/rx.c >>> @@ -678,6 +678,7 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel, >>> "XDP is not possible with multiple receive fragments (%d)\n", >>> channel->rx_pkt_n_frags); >>> channel->n_rx_xdp_bad_drops++; >>> + trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act); >>> return false; >>> } >> AIUI trace_xdp_exception() is improper here as we have not run >> the XDP program (and xdp_act is thus uninitialised). >> >> The other three, below, appear to be correct. >> -Ed >> > > Good point. Do you know under what conditions we'd end up with > "fragmented" packets? As far as I can tell this isn't IP > fragmentation? Fragments in this case means that the packet data are spread across multiple RX buffers (~= memory pages). This should only happen if the RX packet is too big to fit in a single buffer, and when enabling XDP we ensure that the MTU is small enough to prevent that. So in theory this can't happen if the NIC is functioning correctly. -Ed
