From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: xfrm, ip tunnel: non released device reference upon device unregistration Date: Sun, 11 Feb 2018 16:46:48 +0100 Message-ID: <20180211154648.GA24719@breakpoint.cc> References: <20180204132118.6fef9bf0@jimi> <20180206125624.GE15427@breakpoint.cc> <20180206130937.blxbrhmkpe3kt6lh@gauss3.secunet.de> <20180206131509.GA14261@breakpoint.cc> <20180206211946.217783da@jimi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Westphal , Steffen Klassert , netdev@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net, shmulik@metanetworks.com To: Eyal Birger Return-path: Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:57724 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751077AbeBKPuG (ORCPT ); Sun, 11 Feb 2018 10:50:06 -0500 Content-Disposition: inline In-Reply-To: <20180206211946.217783da@jimi> Sender: netdev-owner@vger.kernel.org List-ID: Eyal Birger wrote: Sorry for taking so long to respond. > On Tue, 6 Feb 2018 14:15:09 +0100 > Florian Westphal wrote: > > > Steffen Klassert wrote: > > > I gave the patch a quick try, but still I get this: > > > > > > unregister_netdevice: waiting for dummy1 to become free. Usage > > > count = 2 > > > > Was that with Eyals setup or the bridge one I posted? > > > > If it was Eyals setup, its possible the patch missed hookup > > to whatever tunnel infra is used (the setup I used has ipip tunnel, > > everything is ipv4). > > > > Thanks! > > Indeed the setup I'm testing uses ip6_tunnel. > I have tested a fix in the spirit of the patch and it looks valid > for ip6_tunnel as well. > > It looks though that this change would need to be added to any tunnel > device using dst_cache (vxlan, geneve, gre, ...). Yes. Meanwhile I tested your patch and it works for me too. As your patch is shorter and ipv4/ipv6 seem to take care of refcount put just fine I think your patch is the right way to go. The xfrm_dst size incrase isn't much of a big deal, there is ample of padding at the end so it will still be allocated from same slab. We could reduce num_pols and num_xfrms to u8, which creates a 16 bit hole, then store the cpu number instead of a list pointer. This would limit growth to 16 instead of 24. But, as I said, i do not think its a big deal. > I'm wondering - non-xfrm dsts are already correctly invalidated, > so do you think it makes sense to invalidate caches for devices that > have no xfrm dsts? or maybe I didn't understand the suggestion? See above, I think your patch is the way to go.