On Thu, Mar 15, 2018 at 04:39:25PM +0800, Jason Wang wrote: > > > On 2018年03月14日 11:37, Michael S. Tsirkin wrote: > > > return NULL; > > > case XDP_TX: > > > - xdp_xmit = true; > > > - /* fall through */ > > > + get_page(alloc_frag->page); > > > + alloc_frag->offset += buflen; > > > + if (tun_xdp_xmit(tun->dev, &xdp)) > > > + goto err_redirect; > > > + tun_xdp_flush(tun->dev); > > Why do we have to flush here though? > > It might be a good idea to document the reason in a code comment. > > > > ndo_xdp_xmit() does not touch doorbell, so we need a ndo_xdp_flush() here. > It's the assumption of XDP API I think, so not sure it's worth to mention it > here. > > Thanks
Can't one flush we called after multiple xmit calls?
