On Mon, May 21, 2018 at 11:47:42AM -0400, David Miller wrote: > From: Jason Wang <jasow...@redhat.com> > Date: Fri, 18 May 2018 21:00:43 +0800 > > > We return -EIO on device down but can not raise EPOLLOUT after it was > > up. This may confuse user like vhost which expects tuntap to raise > > EPOLLOUT to re-enable its TX routine after tuntap is down. This could > > be easily reproduced by transmitting packets from VM while down and up > > the tap device. Fixing this by set SOCKWQ_ASYNC_NOSPACE on -EIO. > > > > Cc: Hannes Frederic Sowa <han...@stressinduktion.org> > > Cc: Eric Dumazet <eduma...@google.com> > > Fixes: 1bd4978a88ac2 ("tun: honor IFF_UP in tun_get_user()") > > Signed-off-by: Jason Wang <jasow...@redhat.com> > > I'm no so sure what to do with this patch. > > Like Michael says, this flag bit is only checks upon transmit which > may or may not happen after this point. It doesn't seem to be > guaranteed.
Jason, can't we detect a link up transition and respond accordingly? What do you think? -- MST