From: Jason Wang <jasow...@redhat.com>
Date: Wed, 7 Feb 2018 17:14:46 +0800
> When using devmap to redirect packets between interfaces,
> xdp_do_flush() is usually a must to flush any batched
> packets. Unfortunately this is missed in current tuntap
> implementation.
>
> Unlike most hardware driver which did XDP inside NAPI loop and call
> xdp_do_flush() at then end of each round of poll. TAP did it in the
> context of process e.g tun_get_user(). So fix this by count the
> pending redirected packets and flush when it exceeds NAPI_POLL_WEIGHT
> or MSG_MORE was cleared by sendmsg() caller.
>
> With this fix, xdp_redirect_map works again between two TAPs.
>
> Fixes: 761876c857cb ("tap: XDP support")
> Signed-off-by: Jason Wang <jasow...@redhat.com>
Applied and queued up for -stable, thanks Jason.
